CN113261091A - Composite sheet for forming protective film and method for manufacturing semiconductor chip - Google Patents

Composite sheet for forming protective film and method for manufacturing semiconductor chip Download PDF

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Publication number
CN113261091A
CN113261091A CN201980079821.XA CN201980079821A CN113261091A CN 113261091 A CN113261091 A CN 113261091A CN 201980079821 A CN201980079821 A CN 201980079821A CN 113261091 A CN113261091 A CN 113261091A
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China
Prior art keywords
protective film
forming
film
composite sheet
meth
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CN201980079821.XA
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Chinese (zh)
Inventor
古野健太
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Lintec Corp
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Lintec Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/025—Electric or magnetic properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L21/6835—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
    • H01L21/6836—Wafer tapes, e.g. grinding or dicing support tapes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
    • H01L21/77—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate
    • H01L21/78—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/28—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection
    • H01L23/29—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection characterised by the material, e.g. carbon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2221/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof covered by H01L21/00
    • H01L2221/67—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere
    • H01L2221/683—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L2221/68304—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
    • H01L2221/68327—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support used during dicing or grinding
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2221/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof covered by H01L21/00
    • H01L2221/67—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere
    • H01L2221/683—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L2221/68304—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
    • H01L2221/68377—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support with parts of the auxiliary support remaining in the finished device

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Optics & Photonics (AREA)
  • Plasma & Fusion (AREA)
  • Mechanical Engineering (AREA)
  • Dicing (AREA)
  • Laser Beam Processing (AREA)
  • Adhesive Tapes (AREA)

Abstract

The present invention provides a composite sheet (101) for forming a protective film, which comprises a support sheet (10) and a film (13) for forming a protective film formed on one surface of the support sheet (10), wherein the support sheet (10) comprises a base material (11) and an antistatic layer (17) formed on one surface or both surfaces of the base material, the total light transmittance of the support sheet (10) of the composite sheet (101) for forming a protective film is set to be more than 85%, or the haze is set to be less than 43%, and the surface resistivity of the composite sheet (101) for forming a protective film is set to be 1.0 x 1011Omega/□ or less.

Description

Composite sheet for forming protective film and method for manufacturing semiconductor chip
Technical Field
The present invention relates to a composite sheet for forming a protective film and a method for manufacturing a semiconductor chip.
The present application claims priority based on japanese patent application No. 2018-228529 filed in japan on 12/5/2018, and the contents thereof are incorporated herein.
Background
In recent years, semiconductor devices have been manufactured using a mounting method called a flip-chip (face down) method. In the flip chip system, a semiconductor chip having electrodes such as bumps (bumps) on a circuit formation surface is used, and the electrodes are bonded to a substrate. Therefore, a surface (back surface) of the semiconductor chip opposite to the circuit formation surface may be exposed.
A resin film containing an organic material may be formed as a protective film on the back surface of the exposed semiconductor chip, and the semiconductor chip with the protective film may be incorporated into a semiconductor device.
The protective film is used to prevent cracks from being generated on the semiconductor chip after a dicing process or encapsulation.
Such a protective film can be formed by curing a curable protective film-forming film, for example. In addition, a non-curable film for forming a protective film, the physical properties of which have been adjusted, may be used as the protective film as it is. The protective film forming film is attached to the back surface of the semiconductor wafer. The protective film-forming film may be attached to the back surface of the semiconductor wafer in a state of a composite sheet for protective film formation which is integrated with a support sheet used when the semiconductor wafer is processed, or may be attached to the back surface of the semiconductor wafer in a state of not being integrated with the support sheet.
After the composite sheet for forming a protective film is attached to the back surface of the semiconductor chip through the protective film forming film, operations such as forming a protective film by curing the protective film forming film, cutting the protective film forming film or the protective film, dividing (dicing) the semiconductor wafer into semiconductor chips, picking up the semiconductor chips (semiconductor chips with protective film forming film or semiconductor chips with protective film) having the cut protective film forming film or protective film on the back surface from the support sheet, and the like are performed at appropriate timings. When picking up the semiconductor chip with the film for forming a protective film, the film for forming a protective film is cured to produce a semiconductor chip with a protective film, and finally the semiconductor chip with a protective film is used to manufacture a semiconductor device. In this manner, the support sheet in the composite sheet for forming a protective film can be used as a dicing sheet. In the case where the protective film-forming film is non-curable, the protective film-forming film is regarded as a protective film in each of the above steps.
On the other hand, after the protective film forming film is attached to the back surface of the semiconductor wafer in a state where the protective film forming film is not integrated with the support sheet, the support sheet is attached to an exposed surface of the protective film forming film on the opposite side to the attachment surface of the semiconductor wafer. Then, a semiconductor chip with a protective film or a semiconductor chip with a film for forming a protective film is obtained in the same manner as in the case of using the composite sheet for forming a protective film, and a semiconductor device is manufactured. In this case, the film for forming a protective film is attached to the back surface of the semiconductor wafer in a state of not being integrated with the support sheet, but is integrated with the support sheet after attachment to constitute the composite sheet for forming a protective film.
When the composite sheet for forming a protective film is wound into a roll, the exposed surface of the base material of the composite sheet for forming a protective film has a surface having irregularities (uneven surface) in order to prevent adhesion between the contact surfaces of the roll. The contact surface refers to an exposed surface of a base material as a lowermost layer of the composite sheet for forming a protective film and an exposed surface of an uppermost layer such as a release film. In particular, if blocking occurs in the protective film-forming composite sheet, wrinkles occur in the sheet, and when the sheet is taken out from a roll, the uppermost layer (usually, a release film) is peeled off from the sheet.
On the other hand, if one contact surface of the roll is an uneven surface, the contact area of the roll is reduced, and therefore blocking is suppressed.
On the other hand, laser light is irradiated to print a surface of the protective film attached to the semiconductor wafer or the semiconductor chip on the support sheet side (in this specification, the protective film may be referred to as "laser printing"). In this case, if the exposed surface of the support sheet (base material) has irregularities, the visibility of laser printing of the protective film through the base material is reduced.
As such a protective film-forming composite sheet capable of preventing visibility by laser printing, for example, a protective film-forming composite sheet is disclosed which uses a base material having only one surface having irregularities and which is disposed so as to face the protective film-forming film side without the irregularities being an exposed surface (dicing tape-integrated semiconductor back surface protective film) (see patent document 1). In the composite sheet for forming a protective film, the haze of a laminated sheet (dicing tape) in which a base material and an adhesive layer are laminated is 45% or less.
However, the composite sheet for forming a protective film disclosed in patent document 1 has a problem that the above blocking cannot be suppressed when wound into a roll because the exposed surface of the base material is a smooth surface.
On the other hand, when the release film is removed from the protective film forming film in the protective film forming composite sheet before the protective film forming composite sheet is attached to the back surface of the semiconductor wafer, the protective film forming composite sheet may be electrically charged. In the stage before the electrically charged composite sheet for forming a protective film is attached to a semiconductor wafer, small foreign matters are easily adsorbed on the film for forming a protective film, and therefore, foreign matters are easily mixed between the film for forming a protective film and the semiconductor wafer.
In the process of manufacturing a semiconductor chip having a protective film on the back surface thereof using a semiconductor wafer and the protective film-forming composite sheet, a laminate is produced which is formed by sequentially laminating a support sheet, a cut protective film or a protective film-forming film, and a semiconductor chip. In addition, when the laminate is handled, the laminate is fixed to the table, and then the laminate is separated from the fixing surface on the table, but when the laminate is separated from the table, the laminate is easily electrified. If the laminate is electrified, the circuit may be broken. In this specification, a phenomenon in which layers in contact with each other are electrified due to peeling between the layers is collectively referred to as "peeling electrification", and includes: a phenomenon that the composite sheet for forming a protective film is electrified when a release film is removed from the film for forming a protective film in the composite sheet for forming a protective film, or a phenomenon that the laminate is electrified when the laminate is separated from a table.
On the other hand, as a semiconductor processing sheet for suppressing peeling electrification, a dicing tape-integrated adhesive sheet is disclosed which comprises a dicing tape (corresponding to the support sheet) having an adhesive layer laminated on a substrate and an adhesive sheet formed on the adhesive layer, wherein when the adhesive layer and the adhesive sheet are peeled at a peeling speed of 10 m/min and a peeling angle of 150 °, the absolute value of peeling static voltage is 0.5kV or less (see patent document 2). According to patent document 2, by using the dicing tape-integrated adhesive sheet, when the semiconductor element to which the adhesive sheet is attached is peeled from the dicing tape in the pickup step, peeling electrification between the adhesive sheet and the dicing tape is suppressed, generation of static electricity is suppressed, and destruction of a circuit on the semiconductor element due to the static electricity is suppressed.
Documents of the prior art
Patent document
Patent document 1: japanese patent No. 5432853
Patent document 2: japanese patent No. 6077922
Disclosure of Invention
Technical problem to be solved by the invention
However, even though the dicing tape-integrated adhesive sheet disclosed in patent document 2 can suppress peeling electrification, it is not certain whether or not it can suppress a decrease in laser printing visibility of the protective film through the substrate due to the exposed surface of the substrate being uneven.
The purpose of the present invention is to provide a composite sheet for forming a protective film, which is provided with a support sheet and a film for forming a protective film, can suppress peeling electrification, and has excellent visibility of laser printing of the protective film through a substrate, and a method for manufacturing a semiconductor chip using the composite sheet for forming a protective film.
Means for solving the problems
A first aspect of the present invention provides a protective film forming methodComposite sheet, it possesses the backing sheet and forms and is in film for protective film formation on one side of backing sheet, wherein, the backing sheet possesses the substrate and forms the antistatic layer on the one side or the two sides of substrate, the total luminousness of backing sheet is more than 85%, the surface resistivity of composite sheet for protective film formation is 1.0 x 1011Omega/□ or less.
In the composite sheet for forming a protective film according to the first aspect of the present invention, the haze of the support sheet is preferably 43% or less, more preferably 41% or less, and still more preferably 40% or less.
In addition, a second aspect of the present invention provides a composite sheet for forming a protective film, comprising a support sheet and a film for forming a protective film formed on one surface of the support sheet, wherein the support sheet comprises a base material and an antistatic layer formed on one surface or both surfaces of the base material, the support sheet has a haze of 43% or less, and the composite sheet for forming a protective film has a surface resistivity of 1.0 × 1011Omega/□ or less.
In the composite sheet for forming a protective film according to the first and second aspects of the present invention, the thickness of the antistatic layer may be 200nm or less.
Further, a third aspect of the present invention provides a method for manufacturing a semiconductor chip, including: a step of attaching a film for forming a protective film in the composite sheet for forming a protective film to a semiconductor wafer; forming a protective film by curing the protective film-forming film attached to the semiconductor wafer; cutting the semiconductor wafer and cutting the protective film or the film for forming the protective film to obtain a plurality of semiconductor chips each including the cut protective film or the film for forming the protective film; and a step of separating and picking up the semiconductor chip provided with the cut protective film or the film for forming the protective film from the support sheet, wherein the manufacturing method further comprises a step of irradiating the film for forming the protective film or the protective film with laser light and printing the printed matter between the step of attaching and the step of picking up.
Effects of the invention
According to the present invention, there can be provided a protective film-forming composite sheet which is capable of suppressing peeling electrification and which is excellent in visibility of laser printing of a protective film via a base material, and a method for manufacturing a semiconductor chip using the protective film-forming composite sheet.
Drawings
Fig. 1 is a sectional view schematically showing a composite sheet for forming a protective film according to an embodiment of the present invention.
Fig. 2 is a sectional view schematically showing a composite sheet for forming a protective film according to an embodiment of the present invention.
Fig. 3 is a sectional view schematically showing a composite sheet for forming a protective film according to an embodiment of the present invention.
Fig. 4 is a sectional view schematically showing a composite sheet for forming a protective film according to an embodiment of the present invention.
Fig. 5 is a sectional view schematically showing a composite sheet for forming a protective film according to an embodiment of the present invention.
Fig. 6 is a sectional view schematically showing a composite sheet for forming a protective film according to an embodiment of the present invention.
Fig. 7A is a sectional view for schematically illustrating a method of manufacturing a semiconductor chip of one embodiment of the present invention.
Fig. 7B is a sectional view for schematically illustrating a method of manufacturing a semiconductor chip of one embodiment of the present invention.
Fig. 7C is a sectional view for schematically illustrating a method of manufacturing a semiconductor chip of one embodiment of the present invention.
Fig. 7D is a sectional view for schematically illustrating a method of manufacturing a semiconductor chip of one embodiment of the present invention.
Fig. 7E is a sectional view for schematically illustrating a method of manufacturing a semiconductor chip of one embodiment of the present invention.
Fig. 8A is a sectional view for schematically illustrating a method of manufacturing a semiconductor chip of one embodiment of the present invention.
Fig. 8B is a sectional view for schematically illustrating a method of manufacturing a semiconductor chip of one embodiment of the present invention.
Fig. 8C is a sectional view for schematically illustrating a method of manufacturing a semiconductor chip of one embodiment of the present invention.
Fig. 8D is a sectional view for schematically illustrating a method of manufacturing a semiconductor chip of one embodiment of the present invention.
Fig. 8E is a sectional view for schematically illustrating a method of manufacturing a semiconductor chip of one embodiment of the present invention.
Fig. 9A is a sectional view for schematically illustrating a method of manufacturing a semiconductor chip of one embodiment of the present invention.
Fig. 9B is a sectional view for schematically illustrating a method of manufacturing a semiconductor chip of one embodiment of the present invention.
Fig. 9C is a sectional view for schematically illustrating a method of manufacturing a semiconductor chip of one embodiment of the present invention.
Fig. 9D is a sectional view for schematically illustrating a method of manufacturing a semiconductor chip of one embodiment of the present invention.
Fig. 9E is a sectional view for schematically illustrating a method of manufacturing a semiconductor chip of one embodiment of the present invention.
Detailed Description
Diamond compact for forming protective film
A composite sheet for forming a protective film according to one embodiment of the present invention comprises a support sheet and a film for forming a protective film formed on one surface of the support sheet, wherein the support sheet comprises a base material and an antistatic layer formed on one surface or both surfaces of the base material, the support sheet has a total light transmittance of 85% or more, and the composite sheet for forming a protective film has a surface resistivity of 1.0X 1011Omega/□ or less.
As described above, the surface resistivity of the composite sheet for forming a protective film was 1.0X 1011Omega/□ or less, the usual electrification can be suppressed (in this specification, sometimes referred to as "usual electrification").
The composite sheet for forming a protective film of the present embodiment has an effect of suppressing electrification at ordinary times by having a layer containing an antistatic agent (in this specification, sometimes collectively referred to as "antistatic layer").
In the composite sheet for forming a protective film, the degree of the effect of suppressing electrification in the ordinary period, in other words, the level of the surface resistivity can be adjusted by adjusting the content of the antistatic agent of the antistatic layer, for example.
On the other hand, in the manufacturing process of a semiconductor device, laser printing is performed by irradiating a surface of a protective film or a protective film forming film attached to a semiconductor wafer or a semiconductor chip on the support sheet side with laser light. The laser-printed protective film-forming film becomes a printed protective film by curing. In the composite sheet for forming a protective film, the total light transmittance of the support sheet is 85% or more, whereby the laser printing visibility of the protective film is increased.
< Total light transmittance of support sheet >
The total light transmittance of the support sheet in the composite sheet for forming a protective film is 85% or more, preferably 90% or more. When the total light transmittance of the support sheet is not less than the lower limit value, the laser printing visibility of the protective film is improved.
The upper limit of the total light transmittance of the support sheet in the composite sheet for forming a protective film is not particularly limited, but is preferably higher. The total light transmittance of the support sheet is preferably 99% or less in consideration of the ease of manufacturing the support sheet, the degree of freedom of the support sheet structure, and the like.
As described in examples hereinafter, the total light transmittance of the support sheet can be measured according to JIS K7361: 1997 using a white LED (5V, 3W) as a light source.
< haze of support sheet >
The haze of the support sheet in the composite sheet for forming a protective film is not particularly limited, but is preferably 43% or less, more preferably 41% or less, and particularly preferably 40% or less. When the total light transmittance of the support sheet is not less than the lower limit value and the haze of the support sheet is not more than the upper limit value, the visibility of the protective film through the support sheet by laser printing is further increased.
The lower limit of the haze of the support sheet in the composite sheet for forming a protective film is not particularly limited, and is preferably lower. The haze of the support sheet may be 30% or more in consideration of ease of manufacturing the support sheet, the degree of freedom of the support sheet structure, and the like.
The haze of the support sheet was measured according to JIS K7136: 2000 using a white LED (5V, 3W) as a light source.
In addition, the composite sheet for forming a protective film according to one embodiment of the present invention includes a support sheet and a film for forming a protective film formed on one surface of the support sheet, the support sheet includes a base material and an antistatic layer formed on one surface or both surfaces of the base material, the support sheet has a haze of 43% or less, and the composite sheet for forming a protective film has a surface resistivity of 1.0 × 1011Omega/□ or less.
When the haze of the protective film-forming composite sheet is 43% or less, preferably 41% or less, and more preferably 40% or less, the laser printing visibility of the protective film is increased.
< surface resistivity of outermost layer on the support sheet side in composite sheet for forming protective film >
The surface resistivity of the composite sheet for forming a protective film is 1.0X 1011Omega/□ or less, preferably 9.5X 1010Omega/□ or less, for example, 5.0X 1010Omega/□ below, 6.0X 109Omega/□ or less and 1.0X 109Any range below Ω/□. By setting the surface resistivity to the upper limit or less, the electrification of the composite sheet for forming a protective film can be suppressed at ordinary times.
The lower limit of the surface resistivity of the composite sheet for forming a protective film is preferably smaller, and is not particularly limited. For example, the surface resistivity is 1.0X 105The composite sheet for forming a protective film having a Ω/□ or more can be produced more easily.
The surface resistivity of the composite sheet for forming a protective film may be adjusted within a range set by arbitrarily combining the preferable lower limit and upper limitWhen adjusted. For example, in one embodiment, the surface resistivity is preferably 1.0 × 105～1.0×1011Omega/□, more preferably 1.0X 105～9.5×1010Omega/□, for example, may be 1.0X 105～5.0×1010Ω/□、1.0×105～6.0×109Omega/□ and 1.0X 105～1.0×109Any range of Ω/□. These ranges are but one example of the surface resistivity.
When the film for forming a protective film in the composite sheet for forming a protective film has curability, the surface resistivity of the composite sheet for forming a protective film described above may be the surface resistivity of the film for forming a protective film before curing or the surface resistivity of the film for forming a protective film after curing, regardless of the thermosetting property or the energy ray curability described later.
As described in examples below, the surface resistivity of the composite sheet for forming a protective film can be measured by using a surface resistance tester with the outermost layer on the support sheet side in the composite sheet for forming a protective film as a measurement target and setting an applied voltage to 100V.
< the surface resistivity of the film for forming a thermosetting protective film after thermal curing >
When the film for forming the protective film is thermosetting as described later, it is preferable that the surface resistivity of the composite sheet for forming the protective film after the film for forming the protective film in the composite sheet for forming the protective film is thermally cured satisfies the above-mentioned condition of the surface resistivity (for example, 1.0 × 1011Upper limit value or lower limit value of Ω/□ or the like), in which case the protective film forming film in the protective film forming composite sheet is preferably heat-cured at 130 ℃ for 2 hours. That is, one embodiment of the composite sheet for forming a protective film includes a composite sheet for forming a protective film in which the surface resistivity after heat curing at 130 ℃ for 2 hours of a film for forming a protective film is 1.0 × 1011The protective film having a thickness of not more than omega/□ is formed into a composite sheet. However, this is only one example of the composite sheet for forming a protective film that satisfies the above-described condition of surface resistivity.
< the surface resistivity of the film for forming a thermosetting protective film before thermal curing >
When the film for forming the protective film is thermosetting as described later, the surface resistivity of the composite sheet for forming the protective film before the film for forming the protective film in the composite sheet for forming the protective film is thermally cured may satisfy the above-mentioned condition of the surface resistivity (for example, 1.0 × 1011Upper limit or lower limit of Ω/□ or the like).
However, in the present embodiment, the surface resistivity of the composite sheet for forming a protective film before the film for forming a protective film in the composite sheet for forming a protective film is thermally cured is preferably 5.0 × 1010Omega/□ or less, for example, 6.0X 109Omega/□ below, 5.0X 108Omega/□ or less and 3.0X 108Any range below Ω/□. By setting the surface resistivity before heat curing to the upper limit or less, electrification of the composite sheet for forming a protective film after heat curing of the film for forming a protective film can be further suppressed at ordinary times.
The lower limit of the surface resistivity of the composite sheet for forming a protective film before the film for forming a protective film is thermally cured is preferably smaller, and is not particularly limited. For example, the surface resistivity before heat curing is 1.0X 105The composite sheet for forming a protective film having a Ω/□ or more can be produced more easily.
The surface resistivity of the composite sheet for forming a protective film before the film for forming a protective film is thermally cured may be appropriately adjusted within a range set by arbitrarily combining the preferable lower limit and upper limit. For example, in one embodiment, the surface resistivity before thermal curing is preferably 1.0X 105～5.0×1010Omega/□, for example, may be 1.0X 105～6.0×109Ω/□、1.0×105～5.0×108Omega/□ and 1.0X 105～3.0×108Any range of Ω/□. These ranges are but one example of the surface resistivity prior to thermal curing.
When the protective film-forming film is thermosetting, the composite sheet for forming a protective film of the present embodiment preferably satisfies both the condition of the surface resistivity after the thermosetting protective film-forming film is thermally cured and the condition of the surface resistivity before the thermosetting protective film-forming film is thermally cured.
The layers constituting the composite sheet for forming a protective film will be described in detail below.
Supporting piece
The support sheet may be formed of one layer (single layer) or may be formed of a plurality of layers of two or more layers. When the support sheet is composed of a plurality of layers, the constituent materials and thicknesses of the plurality of layers may be the same as or different from each other, and the combination of the plurality of layers is not particularly limited as long as the effect of the present invention is not impaired.
In the present specification, the phrase "a plurality of layers may be the same or different from each other" means "all the layers may be the same or all the layers may be different from each other, and only a part of the layers may be the same" and "a plurality of layers are different from each other" means "at least one of the constituent material and the thickness of each layer is different from each other" in the case of not being limited to the support sheet.
The support sheet may be transparent or opaque, and may be colored according to the purpose.
For example, when the protective film-forming film has energy ray curability, the support sheet preferably transmits energy rays.
For example, in order to optically inspect the film for forming the protective film in the composite sheet for forming the protective film through the support sheet, the support sheet is preferably transparent.
In the present specification, "energy ray" refers to a ray having an energy quantum in an electromagnetic wave or a charged particle beam. Examples of the energy ray include ultraviolet rays, radiation, and electron beams. For example, the ultraviolet rays can be irradiated by using a high-pressure mercury lamp, a fusion lamp (fusion lamp), a xenon lamp, a black light lamp, an LED lamp, or the like as an ultraviolet ray source. The electron beam can be irradiated with an electron beam generated by an electron beam accelerator or the like.
In the present specification, "energy ray-curable property" refers to a property of curing by irradiation with an energy ray, and "non-energy ray-curable property" refers to a property of not curing even by irradiation with an energy ray
Examples of the support sheet include a support sheet having a base material and an adhesive layer formed on the base material, and a support sheet composed of only a base material.
On the other hand, as described above, in the composite sheet for forming a protective film, any one of the layers may be an antistatic layer.
In this case, preferable examples of the support sheet include: a support sheet that is provided with a base material, and in which an antistatic layer (in this specification, sometimes abbreviated as "back antistatic layer") is provided on a surface of the base material on the side opposite to the protective film-forming film side; the support sheet is provided with a base material, and the protective film-forming composite sheet is provided with an antistatic layer (in this specification, sometimes abbreviated as "surface antistatic layer") formed on the surface of the base material on the protective film-forming film side. The antistatic layers (back antistatic layer and surface antistatic layer) contain an antistatic agent.
That is, preferable examples of the composite sheet for forming a protective film include: the support sheet is provided with a base material and a protective film-forming composite sheet comprising antistatic layers formed on one or both surfaces of the base material.
In the present specification, the "antistatic layer formed on one side of the substrate" means "the back antistatic layer or the surface antistatic layer". And, the "antistatic layers formed on both sides of the base material" means "a combination of the back surface antistatic layer and the surface antistatic layer".
Among these, the support sheet is more preferably a protective film-forming composite sheet comprising the base material and the back surface antistatic layer.
The protective film-forming composite sheet may include: and a protective film forming composite sheet having, as an antistatic layer, a layer that does not belong to either the back antistatic layer or the front antistatic layer.
For example, the antistatic layer may be provided on the surface of the protective film-forming film opposite to the support sheet side, and the protective film-forming film may have antistatic properties. However, although the use of such a protective film-forming composite sheet can sufficiently suppress electrification, in the production of a semiconductor device, the antistatic layer is attached to the semiconductor chip via the antistatic layer (i.e., the antistatic layer provided on the surface of the protective film-forming film opposite to the support sheet) and incorporated into the semiconductor device. In this case, in the process of manufacturing a semiconductor device, a state in which the protective film-forming film or the protective film is attached to the semiconductor wafer or the semiconductor chip via the antistatic layer may not be stably maintained. In addition, in the semiconductor device, the antistatic layer may adversely affect the structural stability of the semiconductor device or the performance of the semiconductor device.
Further, for example, an antistatic layer may be provided on the face of the protective film forming film on the support sheet side. However, when a semiconductor device is manufactured using such a protective film forming composite sheet, a semiconductor chip having a protective film forming film or a protective film attached thereto is separated from an antistatic layer on a support sheet and picked up, and a process abnormality may occur due to the presence of the antistatic layer in the middle.
On the other hand, by using the back surface antistatic layer or the surface antistatic layer as the antistatic layer, not only electrification at the time of removing the laminate but also occurrence of troubles due to electrification can be suppressed under more situations in the production process or the storage process of the composite sheet for forming a protective film.
From the above viewpoint, the composite sheet for forming a protective film preferably includes the back surface antistatic layer or the surface antistatic layer as an antistatic layer.
Hereinafter, an example of the overall configuration of the composite sheet for forming a protective film will be described with reference to the drawings for each arrangement of antistatic layers. For convenience, important parts may be enlarged and shown in the drawings used in the following description, and the dimensional ratios of the respective components are not necessarily the same as those in actual cases.
First, a composite sheet for forming a protective film, which is provided with the back surface antistatic layer as an antistatic layer, will be described.
Fig. 1 is a sectional view schematically showing a composite sheet for forming a protective film according to an embodiment of the present invention.
The composite sheet 101 for forming a protective film shown here includes a support sheet 10 and a film 13 for forming a protective film formed on one surface (in this specification, may be referred to as a "first surface") 10a of the support sheet 10.
The support sheet 10 includes a base material 11, an adhesive layer 12 formed on one surface (in this specification, sometimes referred to as a "first surface") 11a of the base material 11, and a back surface antistatic layer 17 formed on the other surface (in this specification, sometimes referred to as a "second surface") 11b of the base material 11. That is, the support sheet 10 is configured by sequentially laminating the back surface antistatic layer 17, the base material 11, and the adhesive layer 12 in the thickness direction thereof. In other words, the first surface 10a of the support sheet 10 is a surface (in this specification, may be referred to as "first surface") 12a of the adhesive layer 12 on the side opposite to the base material 11.
That is, the composite sheet 101 for forming a protective film is configured by laminating the back surface antistatic layer 17, the base material 11, the adhesive layer 12, and the film 13 for forming a protective film in this order in the thickness direction thereof. The composite sheet 101 for forming a protective film further includes a release film 15 on the film 13 for forming a protective film.
In the composite sheet 101 for forming a protective film, the film 13 for forming a protective film is laminated over the entire surface or almost the entire surface of the first surface 12a of the adhesive layer 12, the adhesive layer 16 for a jig is laminated on a part of the surface 13a of the film 13 for forming a protective film opposite to the adhesive layer 12 (in this specification, sometimes referred to as "first surface"), that is, a region near the peripheral edge, and the release film 15 is laminated on the surface of the first surface 13a of the film 13 for forming a protective film, on which the adhesive layer 16 for a jig is not laminated, and the surface (in this specification, sometimes referred to as "first surface") 16a of the adhesive layer 16 for a jig opposite to the adhesive layer 12.
In the composite sheet 101 for forming a protective film, a part of a gap may be generated between the release film 15 and a layer directly contacting the release film 15.
For example, although the release film 15 is shown in a state of being in contact with (laminated on) the side surface 16c of the pressure-sensitive adhesive layer 16 for a jig, the release film 15 may not be in contact with the side surface 16 c. Here, although the release film 15 is shown in a state of being in contact with (laminated on) the region near the jig pressure-sensitive adhesive layer 16 on the first surface 13a of the protective film forming film 13, the release film 15 may not be in contact with the region.
In addition, the boundary between the first surface 16a and the side surface 16c of the pressure-sensitive adhesive layer 16 for a jig may not be clearly distinguished. This is also the same for the composite sheet for forming a protective film of the other embodiment having the pressure-sensitive adhesive layer for a jig.
The base material before processing used for the support sheet is generally a concave-convex surface having a concave-convex shape on one surface or both surfaces thereof. This is because, if the substrate does not have such an uneven surface, the contact surfaces of the substrates stick to each other and block when the substrate is wound into a roll, and it becomes difficult to use the roll. If at least one of the contact surfaces of the substrates is a concave-convex surface, the contact surface area is reduced, and therefore blocking can be suppressed.
Therefore, in the composite sheet 101 for forming a protective film, either one or both of the first surface 11a and the second surface 11b of the base material 11 may be an uneven surface. When only one of the first surface 11a and the second surface 11b of the substrate 11 is a concave-convex surface, either surface may be a concave-convex surface. At this time, the other surface is a smooth surface having a low degree of unevenness.
The conditions of the uneven surface and the smooth surface are the same in the composite sheet for forming another protective film provided with the substrate 11.
The jig adhesive layer 16 is used to fix the composite sheet 101 for forming a protective film to a jig such as a ring frame.
The pressure-sensitive adhesive layer 16 for a jig may have, for example, a single-layer structure containing a pressure-sensitive adhesive component, or may have a multilayer structure in which layers containing a pressure-sensitive adhesive component are laminated on both surfaces of a sheet as a core material.
The back antistatic layer 17 contains an antistatic agent. Thus, the back surface of the outermost layer on the side of the support sheet 10 in the composite sheet 101 for forming a protective film is made antistaticThe surface resistivity of the electrical layer 17 was 1.0X 1011Omega/□ or less. Further, electrification of the composite sheet 101 for forming a protective film is suppressed at ordinary times.
The composite sheet 101 for forming a protective film is used in the following manner: in a state where the release film 15 is removed, the back surface of the semiconductor wafer (not shown) is attached to the first surface 13a of the protective film forming film 13, and the first surface 16a of the jig adhesive layer 16 is further attached to a jig such as a ring frame.
Fig. 2 is a sectional view schematically showing a composite sheet for forming a protective film according to another embodiment of the present invention.
In the drawings in fig. 2 and subsequent figures, the same reference numerals as in the already-described figures are assigned to the same constituent elements as those shown in the already-described figures, and detailed description thereof will be omitted.
The composite sheet 102 for forming a protective film shown here is the same as the composite sheet 101 for forming a protective film shown in fig. 1, except that the shape and size of the film for forming a protective film are different, and the adhesive layer for a jig is laminated on the first surface of the adhesive layer instead of the first surface of the film for forming a protective film.
More specifically, in the composite sheet for forming a protective film 102, the film 23 for forming a protective film is laminated on a partial region of the first surface 12a of the adhesive layer 12, that is, a region on the center side in the width direction (the left-right direction in fig. 2) of the adhesive layer 12. Further, the pressure-sensitive adhesive layer 16 for a jig is laminated on a surface of the first surface 12a of the adhesive layer 12 on which the protective film-forming film 23 is not laminated, that is, on a region in the vicinity of the peripheral edge portion. The release film 15 is laminated on a surface (in this specification, it may be referred to as a "first surface") 23a of the protective film forming film 23 opposite to the adhesive layer 12 side and a first surface 16a of the jig adhesive layer 16.
When the composite sheet for forming a protective film 102 is viewed from above in a downward direction, the surface area of the first surface 23a of the protective film 23 is smaller than the surface area of the first surface 12a of the adhesive layer 12 (i.e., the region in which the protective film 23 is laminated and the region in which the protective film 23 is not laminated), and has a planar shape such as a circle.
In the composite sheet 102 for forming a protective film, a part of a gap may be generated between the release film 15 and a layer in direct contact with the release film 15.
For example, although the release film 15 is shown in a state of being in contact with (laminated on) the side surface 23c of the protective film forming film 23, the release film 15 may not be in contact with the side surface 23 c. Here, although the release film 15 is shown in a state of being in contact with (laminated on) a region of the surface 12a of the adhesive agent layer 12 where the protective film forming film 23 and the jig pressure-sensitive adhesive layer 16 are not laminated, the release film 15 may not be in contact with the region.
In addition, the boundary between the first surface 23a and the side surface 23c of the protective film forming film 23 may not be clearly defined. This is the same for the composite sheet for forming a protective film of the other embodiments having the same shape and size of the film for forming a protective film.
The surface resistivity of the back antistatic layer 17 as the outermost layer on the support sheet 10 side in the protective film forming composite sheet 102 was 1.0 × 1011The composite sheet 102 for forming a protective film is suppressed in electrification at ordinary times at a value of Ω/□ or less.
The clad sheet 102 for forming a protective film is used in the following manner: in a state where the release film 15 is removed, the back surface of the semiconductor wafer (not shown) is attached to the first surface 23a of the protective film forming film 23, and the first surface 16a of the jig adhesive layer 16 is further attached to a jig such as a ring frame.
Fig. 3 is a sectional view schematically showing a composite sheet for forming a protective film according to still another embodiment of the present invention.
The composite sheet 103 for forming a protective film shown here is the same as the composite sheet 102 for forming a protective film shown in fig. 2, except that it does not include the pressure-sensitive adhesive layer 16 for a jig.
The surface resistivity of the back antistatic layer 17 as the outermost layer on the support sheet 10 side in the composite sheet 103 for forming a protective film was 1.0 × 1011The electrification of the composite sheet 103 for forming a protective film is suppressed at ordinary times at Ω/□ or less.
The protective film-forming composite sheet 103 is used in the following manner: in a state where the release film 15 is removed, the back surface of the semiconductor wafer (not shown) is attached to the first surface 23a of the protective film forming film 23, and further, a region where the protective film forming film 23 is not laminated in the first surface 12a of the adhesive layer 12 is attached to a jig such as a ring frame.
Fig. 4 is a sectional view schematically showing a composite sheet for forming a protective film according to still another embodiment of the present invention.
The composite sheet 104 for forming a protective film shown here is the same as the composite sheet 103 for forming a protective film shown in fig. 3, except that an intermediate layer 18 is further provided between the adhesive layer 12 and the film 23 for forming a protective film. The composite sheet 104 for forming a protective film includes the intermediate layer 18 on the first surface 12a of the adhesive layer 12. A surface (in this specification, sometimes referred to as "first surface") 18a of the intermediate layer 18 opposite to the adhesive layer 12 side is a lamination surface of the protective film-forming film 23.
That is, the composite sheet 104 for forming a protective film is configured by sequentially laminating the back antistatic layer 17, the base material 11, the adhesive layer 12, the intermediate layer 18, and the film 23 for forming a protective film in the thickness direction thereof. The composite sheet for forming a protective film 104 further includes a release film 15 on the film for forming a protective film 23.
In the protective film forming composite sheet 104, the intermediate layer 18 is disposed between the protective film forming film 23 and the adhesive layer 12, and is disposed at an intermediate position that does not become the outermost layer.
The intermediate layer 18 is not particularly limited as long as it functions at such a position.
More specifically, the intermediate layer 18 is, for example, a release property improving layer having one surface subjected to a release treatment. The peelability improving layer has a function of improving peelability when a semiconductor chip provided with a protective film forming film or a protective film is peeled (peeled) from a support sheet and picked up, the peelability when the semiconductor chip is peeled from the support sheet.
The first surface 18a of the intermediate layer 18 is in contact with a surface (in this specification, sometimes referred to as "second surface") 23b of the protective film-forming film 23 on the adhesive agent layer 12 side.
The shape (i.e., planar shape) and size of the intermediate layer 18 when the composite sheet for forming a protective film 104 is viewed from above in a plan view are not particularly limited as long as the intermediate layer 18 can exert its function. However, in order to sufficiently exhibit the function of the intermediate layer 18, the first surface 18a of the intermediate layer 18 is preferably in contact with the entire surface of the second surface 23b of the protective film-forming film 23. For this reason, the first surface 18a of the intermediate layer 18 preferably has the same or larger area as the second surface 23b of the protective film-forming film 23. On the other hand, the surface (in this specification, sometimes referred to as "second surface") 18b of the intermediate layer 18 on the adhesive agent layer 12 side may be in contact with the entire surface of the first surface 12a of the adhesive agent layer 12, or may be in contact with only a partial region of the first surface 12a of the adhesive agent layer 12. However, in order to sufficiently exhibit the function of the intermediate layer 18, the first surface 12a of the adhesive layer 12 is preferably in contact with the entire surface of the second surface 18b of the intermediate layer 18.
A preferable example of the intermediate layer 18 is an intermediate layer in which the area and shape of the first surface 18a of the intermediate layer 18 are the same as those of the second surface 23b of the protective film-forming film 23.
In the composite sheet 104 for forming a protective film, a part of a gap may be generated between the release film 15 and a layer directly contacting the release film 15.
For example, although the release film 15 is shown in a state of being in contact with (laminated on) the side surface 18c of the intermediate layer 18, the release film 15 may not be in contact with the side surface 18 c. Here, although the release film 15 is shown in a state of being in contact with (laminated on) a region where the intermediate layer 18 is not laminated in the first surface 12a of the adhesive agent layer 12 including a region in the vicinity of the intermediate layer 18, the release film 15 may not be in contact with a region in the vicinity of the intermediate layer 18 in the first surface 12 a.
In addition, the boundary between the first surface 18a and the side surface 18c of the intermediate layer 18 may not be clearly distinguished.
The surface resistivity of the back antistatic layer 17 as the outermost layer on the support sheet 10 side in the protective film forming composite sheet 104 was 1.0 × 1011Omega/□ or less, electrification of the composite sheet 104 for forming a protective film is suppressed at ordinary times.
The clad sheet 104 for forming a protective film is used in the following manner: in a state where the release film 15 is removed, the back surface of the semiconductor wafer (not shown) is attached to the first surface 23a of the protective film forming film 23, and further, a region where the intermediate layer 18 is not laminated in the first surface 12a of the adhesive layer 12 is attached to a jig such as a ring frame.
Fig. 5 is a sectional view schematically showing a composite sheet for forming a protective film according to still another embodiment of the present invention.
The composite sheet 105 for forming a protective film shown here is the same as the composite sheet 101 for forming a protective film shown in fig. 1, except that it does not include the adhesive layer 12. In other words, the composite sheet 105 for forming a protective film is the same as the composite sheet 101 for forming a protective film except that the backup sheet 20 is provided instead of the backup sheet 10, and the backup sheet 20 does not have the adhesive agent layer 12. In other words, the first surface 11a of the base material 11 is a surface (in this specification, may be referred to as "first surface") 20a of the support sheet 20 on the side of the protective film forming film 13.
The surface resistivity of the back antistatic layer 17 as the outermost layer on the support sheet 20 side in the composite sheet 105 for forming a protective film was 1.0 × 1011The composite sheet 105 for forming a protective film is suppressed in electrification at ordinary times at Ω/□ or less.
The protective film-forming composite sheet 105 is used in the following manner: in a state where the release film 15 is removed, the back surface of the semiconductor wafer (not shown) is attached to the first surface 13a of the protective film forming film 13, and the first surface 16a of the jig adhesive layer 16 is further attached to a jig such as a ring frame.
The composite sheet for forming a protective film provided with the back surface antistatic layer as an antistatic layer is not limited to the composite sheet for forming a protective film shown in fig. 1 to 5. For example, the composite sheet for forming a protective film of the present embodiment may be a composite sheet for forming a protective film obtained by modifying or deleting a part of the composition of the composite sheet for forming a protective film shown in fig. 1 to 5, or a composite sheet for forming a protective film obtained by further adding another composition to the composite sheet for forming a protective film shown in fig. 1 to 5, within a range not to impair the effects of the present invention.
The composite sheet for forming a protective film shown in fig. 5 does not have an adhesive layer. As the composite sheet for forming a protective film of the present embodiment having no adhesive layer, for example, a composite sheet for forming a protective film in which an adhesive layer is omitted in the composite sheet for forming a protective film shown in fig. 2 to 4 can be cited in addition to the composite sheet for forming a protective film of the present embodiment having no adhesive layer.
The composite sheet for forming a protective film shown in fig. 1,2, and 5 includes a pressure-sensitive adhesive layer for a jig. As the composite sheet for forming a protective film of the present embodiment including the pressure-sensitive adhesive layer for a jig, for example, a composite sheet for forming a protective film in which a pressure-sensitive adhesive layer for a jig is newly provided on the first surface of the pressure-sensitive adhesive layer in the composite sheet for forming a protective film shown in fig. 4 can be cited. In this case, the position of the adhesive layer for a jig on the first surface may be the same as the composite sheet for forming a protective film shown in fig. 1,2 and 5.
The composite sheet for forming a protective film shown in fig. 3 to 4 does not have a pressure-sensitive adhesive layer for a jig. As the composite sheet for forming a protective film of the present embodiment which does not include a pressure-sensitive adhesive layer for a jig, for example, a composite sheet for forming a protective film in which a pressure-sensitive adhesive layer for a jig is omitted in the composite sheet for forming a protective film shown in fig. 1 and 5 can be cited.
The composite sheet for forming a protective film shown in fig. 4 includes an intermediate layer. As the composite sheet for forming a protective film of the present embodiment having an intermediate layer, for example, a composite sheet for forming a protective film in which an intermediate layer is newly provided on the second surface side of a film for forming a protective film in the composite sheet for forming a protective film shown in fig. 1,2, and 5 can be cited. In this case, the arrangement of the intermediate layer on the second surface may be the same as that described with reference to fig. 4.
The composite sheet for forming a protective film shown in fig. 1 to 5 does not have any layer except for the back antistatic layer, the base material, the film for forming a protective film, and the release film; or only an adhesive layer in addition to the back antistatic layer, the base material, the protective film-forming film and the release film; or only an adhesive layer and an intermediate layer in addition to the back antistatic layer, the base material, the protective film-forming film and the release film. As the composite sheet for forming a protective film of the present embodiment, in addition to the composite sheet for forming a protective film shown in fig. 1 to 5, for example, there can be mentioned a composite sheet for forming a protective film comprising other layers not belonging to any of the back antistatic layer, the base material, the adhesive agent layer, the intermediate layer, the film for forming a protective film and the release film.
In the composite sheet for forming a protective film of the present embodiment, the size and shape of each layer can be arbitrarily adjusted according to the purpose.
In addition, in the composite sheet for forming a protective film of the present embodiment, a part of a gap may be generated between the release film and a layer in direct contact with the release film.
In the composite sheet for forming a protective film of the present embodiment, the size and shape of each layer can be arbitrarily adjusted according to the purpose.
Next, a composite sheet for forming a protective film, which comprises the surface antistatic layer as an antistatic layer, will be described.
Fig. 6 is a sectional view schematically showing a composite sheet for forming a protective film according to an embodiment of the present invention.
The composite sheet 301 for forming a protective film shown here includes a support sheet 50 and a film 13 for forming a protective film formed on one surface (in this specification, may be referred to as a "first surface") 50a of the support sheet 50.
The support sheet 50 includes a base material 11, a surface antistatic layer 19 formed on a first surface 11a of the base material 11, and an adhesive layer 12 formed on a surface (in this specification, sometimes referred to as "first surface") 19a of the surface antistatic layer 19 opposite to the base material 11 side. That is, the support sheet 50 is configured by sequentially laminating the base material 11, the surface antistatic layer 19, and the adhesive layer 12 in the thickness direction thereof. In other words, the first surface 50a of the support sheet 50 is the first surface 12a of the adhesive layer 12.
Further, reference numeral 19b denotes a surface (in this specification, may be referred to as "second surface") of the surface antistatic layer 19 on the substrate 11 side.
That is, the composite sheet 301 for forming a protective film is configured by laminating the base material 11, the surface antistatic layer 19, the adhesive layer 12, and the film 13 for forming a protective film in this order in the thickness direction thereof. The composite sheet for forming a protective film 301 further includes a release film 15 on the film for forming a protective film 13.
In the composite sheet 301 for forming a protective film, the film 13 for forming a protective film is laminated on the entire surface or almost the entire surface of the first surface 12a of the adhesive agent layer 12, the adhesive layer 16 for a jig is laminated on a part of the first surface 13a of the film 13 for forming a protective film, that is, a region near the peripheral edge, and the release film 15 is laminated on the surface of the first surface 13a of the film 13 for forming a protective film, on which the adhesive layer 16 for a jig is not laminated, and on the first surface 16a of the adhesive layer 16 for a jig.
The protective film forming composite sheet 301 is the same as the protective film forming composite sheet 101 shown in fig. 1, except that the back surface antistatic layer 17 is not provided on the second surface 11b of the base material 11, and the surface antistatic layer 19 is provided on the first surface 11a of the base material 11, more specifically, between the base material 11 and the adhesive layer 12.
The surface antistatic layer 19 is the same as the back antistatic layer 17 described previously.
That is, the composite sheet 301 for forming a protective film can be regarded as a composite sheet for forming a protective film in which the position of the antistatic layer in the composite sheet 101 for forming a protective film is changed from the second surface 11b of the base material 11 to a position between the base material 11 and the adhesive layer 12.
The surface antistatic layer 19 contains an antistatic agent. Thus, the surface resistivity of the base material 11, which is the outermost layer on the support sheet 50 side in the composite sheet 301 for forming a protective film, is 1.0 × 1011Omega/□ or less. Further, the electrification of the composite sheet 301 for forming a protective film is suppressed at ordinary times.
The protective film-forming composite sheet 301 is used in the following manner: in a state where the release film 15 is removed, the back surface of the semiconductor wafer (not shown) is attached to the first surface 13a of the protective film forming film 13, and the first surface 16a of the jig adhesive layer 16 is further attached to a jig such as a ring frame.
The composite sheet for forming a protective film provided with the surface antistatic layer as an antistatic layer is not limited to the composite sheet for forming a protective film shown in fig. 6. For example, the composite sheet for forming a protective film of the present embodiment may be a composite sheet for forming a protective film (in other words, a composite sheet for forming a protective film in which the position of the antistatic layer is changed from the second surface of the base material to the first surface of the base material) configured such that the composite sheet for forming a protective film shown in fig. 2 to 5 does not have a back surface antistatic layer and has a front surface antistatic layer on the first surface of the base material.
Further, the protective film-forming composite sheet provided with the surface antistatic layer as the antistatic layer is not limited to the above protective film-forming composite sheet, and any of the protective film-forming composite sheets provided with the back antistatic layer described above may be used in which the position of the antistatic layer is changed from the second surface of the base material to the first surface of the base material.
In the composite sheet for forming a protective film of the present embodiment, the size and shape of each layer can be arbitrarily adjusted according to the purpose.
The composite sheet for forming a protective film according to one embodiment of the present invention may also be provided with both a back surface antistatic layer and a surface antistatic layer as antistatic layers.
As the protective film-forming composite sheet provided with both a back surface antistatic layer and a surface antistatic layer, for example, there is a protective film-forming composite sheet provided with a support sheet and a protective film-forming film formed on one surface (i.e., a first surface) of the support sheet, wherein the support sheet is formed by sequentially laminating a back surface antistatic layer, a base material, a surface antistatic layer, and an adhesive layer in the thickness direction thereof, and the adhesive layer is disposed so as to face the protective film-forming film side.
More specifically, such a composite sheet for forming a protective film is exemplified by a composite sheet 101 for forming a protective film shown in fig. 1, in which a surface antistatic layer (for example, a surface antistatic layer 19 shown in fig. 6) is further provided between the base material 11 and the adhesive agent layer 12.
Further, as a protective film-forming composite sheet provided with both a back surface antistatic layer and a surface antistatic layer, for example, there is a protective film-forming composite sheet provided with a support sheet and a protective film-forming film formed on one surface (i.e., a first surface) of the support sheet, wherein the support sheet is formed by sequentially laminating a back surface antistatic layer, a base material, and a surface antistatic layer in the thickness direction thereof, and the surface antistatic layer is disposed so as to face the protective film-forming film side.
More specifically, this composite sheet for forming a protective film includes a composite sheet for forming a protective film in which a surface antistatic layer (for example, the surface antistatic layer 19 shown in fig. 6) is provided in place of the adhesive layer 12 in the composite sheet 101 for forming a protective film shown in fig. 1.
However, these are just examples of composite sheets for forming protective films, which are provided with a back surface antistatic layer, an antistatic base material, and a surface antistatic layer at the same time.
The overall structure of the protective film-forming composite sheet has been described for each arrangement of antistatic layers, and the layers constituting the support sheet will be described next.
O base material
The substrate is in the form of a sheet or a film, and examples of the constituent material include various resins.
Examples of the resin include polyethylene such as Low Density Polyethylene (LDPE), Linear Low Density Polyethylene (LLDPE), and High Density Polyethylene (HDPE); polyolefins other than polyethylene, such as polypropylene, polybutene, polybutadiene, polymethylpentene, and norbornene resins; ethylene copolymers (copolymers obtained using ethylene as a monomer) such as ethylene-vinyl acetate copolymers, ethylene- (meth) acrylic acid ester copolymers, and ethylene-norbornene copolymers; vinyl chloride-based resins (resins obtained using vinyl chloride as a monomer) such as polyvinyl chloride and vinyl chloride copolymers; polystyrene; a polycycloolefin; polyesters such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyethylene isophthalate, polyethylene 2, 6-naphthalate, and wholly aromatic polyesters having an aromatic ring group in all the structural units; copolymers of two or more of said polyesters; poly (meth) acrylates; a polyurethane; a urethane acrylate; a polyimide; a polyamide; a polycarbonate; a fluororesin; a polyacetal; modified polyphenylene ether; polyphenylene sulfide; polysulfones; polyether ketones, and the like.
Examples of the resin include polymer alloys (polymer alloys) such as a mixture of the polyester and a resin other than the polyester. It is preferable that the amount of the resin other than polyester in the polymer alloy of the polyester and the resin other than polyester is smaller.
Examples of the resin include crosslinked resins obtained by crosslinking one or two or more of the above-exemplified resins; modified resins such as ionomers using one or more of the resins exemplified above.
The resin constituting the base material may be one kind only, or two or more kinds, and in the case of two or more kinds, the combination and ratio thereof may be arbitrarily selected.
The substrate may be composed of one layer (single layer) or a plurality of layers of two or more layers, and when composed of a plurality of layers, these plurality of layers may be the same as or different from each other, and the combination of these plurality of layers is not particularly limited.
The thickness of the base material is preferably 30 to 300 μm, and more preferably 50 to 140 μm. When the thickness of the base material is within the above range, the flexibility and adhesiveness to a semiconductor wafer or a semiconductor chip of the composite sheet for forming a protective film are further improved.
Here, the "thickness of the substrate" refers to the thickness of the entire substrate, and for example, the thickness of the substrate composed of a plurality of layers refers to the total thickness of all the layers constituting the substrate.
The substrate is preferably a substrate having high thickness accuracy, that is, a substrate in which variation in thickness is suppressed at any position. Among the above-mentioned constituent materials, examples of materials that can be used to form such a base material with high thickness accuracy include polyethylene, polyolefins other than polyethylene, polyethylene terephthalate, and ethylene-vinyl acetate copolymers.
The base material may contain various known additives such as a filler, a colorant, an antioxidant, an organic lubricant, a catalyst, and a softener (plasticizer), in addition to the main constituent material such as the resin.
The base material can be transparent or opaque, can be colored according to the purpose, and can also be vapor-plated with other layers.
For example, when the protective film-forming film has energy ray curability, the substrate preferably transmits energy rays.
For example, in order to optically inspect the film for forming the protective film in the composite sheet for forming the protective film through the substrate, the substrate is preferably transparent.
In order to improve the adhesion between the substrate and a layer (for example, an adhesive layer, an intermediate layer, or a film for forming a protective film) provided on the substrate, the surface may be subjected to a roughening treatment by sandblasting, solvent treatment, or the like; corona discharge treatment, electron beam irradiation treatment, plasma treatment, ozone-ultraviolet irradiation treatment, flame treatment, chromic acid treatment, hot air treatment, and other oxidation treatments. In addition, the surface of the substrate may be subjected to primer treatment (primer treatment).
The substrate can be manufactured by a known method. For example, a resin-containing substrate can be produced by molding a resin composition containing the resin.
Adhesive layer
The adhesive layer is in a sheet or film shape and contains an adhesive.
Examples of the adhesive include adhesive resins such as acrylic resins, urethane resins, rubber resins, silicone resins, epoxy resins, polyvinyl ethers, polycarbonates, and ester resins, and acrylic resins are preferred.
In addition, in the present specification, the "adhesive resin" includes a resin having adhesiveness and a resin having adhesiveness. For example, the adhesive resin includes not only a resin having self-adhesiveness but also a resin exhibiting adhesiveness by being used together with other components such as an additive, a resin exhibiting adhesiveness due to the presence of a trigger (trigger) such as heat or water, and the like.
The adhesive layer may be composed of one layer (single layer) or a plurality of layers of two or more layers, and in the case of being composed of a plurality of layers, these plurality of layers may be the same as or different from each other, and the combination of these plurality of layers is not particularly limited.
The thickness of the adhesive layer is preferably 1 to 100 μm, more preferably 1 to 60 μm, and particularly preferably 1 to 30 μm.
The "thickness of the adhesive agent layer" refers to the thickness of the entire adhesive agent layer, and for example, the thickness of the adhesive agent layer composed of a plurality of layers refers to the total thickness of all the layers constituting the adhesive agent layer.
The adhesive layer may be transparent or opaque, and may be colored according to the purpose.
For example, when the protective film-forming film has energy ray curability, the adhesive layer preferably transmits energy rays.
For example, in order to optically inspect a film for forming a protective film in the composite sheet for forming a protective film through the adhesive layer, the adhesive layer is preferably transparent.
The adhesive layer may be formed using an energy ray-curable adhesive, or may be formed using a non-energy ray-curable adhesive. That is, the adhesive layer may be either energy ray-curable or non-energy ray-curable. The energy ray-curable adhesive agent layer can be easily adjusted in physical properties before and after curing.
Adhesive composition
The adhesive layer can be formed using an adhesive composition containing an adhesive. For example, an adhesive composition is applied to a surface of an adhesive layer to be formed, and dried as necessary, whereby the adhesive layer can be formed at a target site. The ratio of the contents of the components that do not vaporize at ordinary temperature to each other in the adhesive composition is generally the same as the ratio of the contents of the components to each other in the adhesive layer. In the present specification, "normal temperature" means a temperature at which cooling or heating is not particularly performed, that is, a normal temperature, and includes, for example, a temperature of 15 to 25 ℃.
A more specific method for forming the adhesive layer will be described in detail later together with a method for forming another layer.
The adhesive composition may be applied by a known method, and examples thereof include a method using various coating machines such as a knife coater, a blade coater, a bar coater, a gravure coater, a roll coater, a curtain coater, a die coater, a knife coater, a screen coater, a meyer bar coater, and a kiss coater.
When the adhesive layer is provided on the substrate, for example, the adhesive composition is applied to the substrate and dried as necessary, whereby the adhesive layer may be laminated on the substrate. In addition, when the adhesive layer is provided on the substrate, for example, the adhesive layer may be laminated on the substrate by applying an adhesive composition on a release film and drying it as necessary to form the adhesive layer on the release film and bonding an exposed surface of the adhesive layer to one surface of the substrate. The release film in this case may be removed at any time during the production process or the use process of the composite sheet for forming a protective film.
The drying conditions of the adhesive composition are not particularly limited, but when the adhesive composition contains a solvent described later, it is preferable to perform heat drying. The adhesive composition containing a solvent is preferably dried at 70 to 130 ℃ for 10 seconds to 5 minutes, for example.
When the adhesive layer is energy ray-curable, examples of the adhesive composition containing an energy ray-curable adhesive, that is, an energy ray-curable adhesive composition, include: an adhesive composition (I-1) comprising an adhesive resin (I-1a) which is not curable by energy rays (hereinafter, sometimes abbreviated as "adhesive resin (I-1 a)") and an energy ray-curable compound; an adhesive composition (I-2) comprising an energy ray-curable adhesive resin (I-2a) (hereinafter, sometimes abbreviated as "adhesive resin (I-2 a)") having an unsaturated group introduced into a side chain of a non-energy ray-curable adhesive resin (I-1 a); and an adhesive composition (I-3) comprising the adhesive resin (I-2a) and an energy ray-curable compound.
< adhesive composition (I-1) >
As described above, the adhesive composition (I-1) contains the non-energy ray-curable adhesive resin (I-1a) and the energy ray-curable compound.
[ adhesive resin (I-1a) ]
The adhesive resin (I-1a) is preferably an acrylic resin.
Examples of the acrylic resin include an acrylic polymer having at least a structural unit derived from an alkyl (meth) acrylate.
The acrylic resin may have only one kind of structural unit, or two or more kinds of structural units, and when two or more kinds of structural units are present, the combination and ratio thereof may be arbitrarily selected.
Examples of the alkyl (meth) acrylate include alkyl (meth) acrylates in which the alkyl group constituting the alkyl ester has 1 to 20 carbon atoms, and the alkyl group is preferably linear or branched.
More specific examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-octyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, dodecyl (meth) acrylate, and the like, Tetradecyl (meth) acrylate (myristyl (meth) acrylate), pentadecyl (meth) acrylate, hexadecyl (meth) acrylate (palmityl (meth) acrylate), heptadecyl (meth) acrylate, octadecyl (meth) acrylate (stearate (meth) acrylate), nonadecyl (meth) acrylate, eicosyl (meth) acrylate, and the like.
Preferably, the acrylic polymer has a structural unit derived from an alkyl (meth) acrylate having 4 or more carbon atoms in the alkyl group, from the viewpoint of improving the adhesive force of the adhesive agent layer. Further, the number of carbon atoms of the alkyl group is preferably 4 to 12, more preferably 4 to 8, from the point of further improving the adhesive force of the adhesive agent layer. The alkyl (meth) acrylate in which the alkyl group has 4 or more carbon atoms is preferably an alkyl acrylate.
The acrylic polymer preferably has a structural unit derived from a functional group-containing monomer in addition to a structural unit derived from an alkyl (meth) acrylate.
Examples of the functional group-containing monomer include a functional group-containing monomer which becomes a crosslinking starting point by a reaction of the functional group with a crosslinking agent described later, and a functional group-containing monomer which can introduce an unsaturated group into a side chain of an acrylic polymer by a reaction of the functional group with an unsaturated group in an unsaturated group-containing compound described later.
Examples of the functional group in the functional group-containing monomer include a hydroxyl group, a carboxyl group, an amino group, and an epoxy group.
That is, examples of the functional group-containing monomer include a hydroxyl group-containing monomer, a carboxyl group-containing monomer, an amino group-containing monomer, and an epoxy group-containing monomer.
Examples of the hydroxyl group-containing monomer include hydroxyalkyl (meth) acrylates such as hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate; and non (meth) acrylic unsaturated alcohols (unsaturated alcohols having no (meth) acryloyl skeleton) such as vinyl alcohol and allyl alcohol.
Examples of the carboxyl group-containing monomer include ethylenically unsaturated monocarboxylic acids (monocarboxylic acids having an ethylenically unsaturated bond) such as (meth) acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids (dicarboxylic acids having an ethylenically unsaturated bond) such as fumaric acid, itaconic acid, maleic acid, and citraconic acid; anhydrides of said ethylenically unsaturated dicarboxylic acids; and carboxyalkyl (meth) acrylates such as 2-carboxyethyl methacrylate.
The functional group-containing monomer is preferably a hydroxyl group-containing monomer or a carboxyl group-containing monomer, and more preferably a hydroxyl group-containing monomer.
The functional group-containing monomer constituting the acrylic polymer may be one kind only, or two or more kinds, and in the case of two or more kinds, the combination and ratio thereof may be arbitrarily selected.
In the acrylic polymer, the content of the structural unit derived from the functional group-containing monomer is preferably 1 to 35% by mass, more preferably 2 to 32% by mass, and particularly preferably 3 to 30% by mass, based on the total amount of the structural units.
The acrylic polymer may further have a structural unit derived from another monomer in addition to the structural unit derived from the alkyl (meth) acrylate and the structural unit derived from the functional group-containing monomer.
The other monomer is not particularly limited as long as it can be copolymerized with an alkyl (meth) acrylate or the like.
Examples of the other monomer include styrene, α -methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile, and acrylamide.
The other monomer constituting the acrylic polymer may be only one type, or two or more types, and in the case of two or more types, the combination and ratio thereof may be arbitrarily selected.
The acrylic polymer can be used as the above-mentioned non-energy ray-curable adhesive resin (I-1 a).
On the other hand, a product produced by reacting an unsaturated group-containing compound having an energy ray-polymerizable unsaturated group (energy ray-polymerizable group) with a functional group in the acrylic polymer can be used as the energy ray-curable adhesive resin (I-2 a).
The adhesive resin (I-1a) contained in the adhesive composition (I-1) may be one type or two or more types, and when two or more types are used, the combination and ratio thereof may be arbitrarily selected.
In the adhesive composition (I-1), the content of the adhesive resin (I-1a) is preferably 5 to 99% by mass, more preferably 10 to 95% by mass, and particularly preferably 15 to 90% by mass, based on the total mass of the adhesive composition (I-1).
[ energy ray-curable Compound ]
Examples of the energy ray-curable compound contained in the adhesive composition (I-1) include a monomer or oligomer having an energy ray-polymerizable unsaturated group and curable by irradiation with an energy ray.
Examples of the monomer in the energy ray-curable compound include polyvalent (meth) acrylates such as trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1, 4-butanediol di (meth) acrylate, and 1, 6-hexanediol (meth) acrylate; urethane (meth) acrylate; polyester (meth) acrylates; polyether (meth) acrylates; epoxy (meth) acrylates, and the like.
Examples of the oligomer in the energy ray-curable compound include oligomers obtained by polymerizing the monomers exemplified above.
The energy ray-curable compound is preferably a urethane (meth) acrylate or a urethane (meth) acrylate oligomer in terms of a large molecular weight and a low tendency to decrease the storage modulus of the adhesive layer.
The energy ray-curable compound contained in the adhesive composition (I-1) may be only one kind, or two or more kinds, and when two or more kinds are contained, the combination and ratio thereof may be arbitrarily selected.
In the adhesive composition (I-1), the content of the energy ray-curable compound is preferably 1 to 95% by mass, more preferably 5 to 90% by mass, and particularly preferably 10 to 85% by mass, based on the total mass of the adhesive composition (I-1).
[ crosslinking agent ]
When the acrylic polymer having a structural unit derived from a functional group-containing monomer in addition to a structural unit derived from an alkyl (meth) acrylate is used as the adhesive resin (I-1a), it is preferable that the adhesive composition (I-1) further contains a crosslinking agent.
The crosslinking agent crosslinks the adhesive resins (I-1a) to each other, for example, by reacting with the functional groups.
Examples of the crosslinking agent include isocyanate-based crosslinking agents (crosslinking agents having an isocyanate group) such as toluene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, and adducts of these diisocyanates; epoxy crosslinking agents (crosslinking agents having a glycidyl group) such as ethylene glycol glycidyl ether; aziridine crosslinking agents (crosslinking agents having an aziridinyl group) such as hexa [1- (2-methyl) -azidinyl ] triphosphazine (hexa [1- (2-methyl) -azidinyl ] triphosphatriazine); metal chelate crosslinking agents (crosslinking agents having a metal chelate structure) such as aluminum chelates; an isocyanurate-based crosslinking agent (a crosslinking agent having an isocyanurate skeleton), and the like.
The crosslinking agent is preferably an isocyanate-based crosslinking agent in terms of improving the cohesive force of the adhesive agent to improve the adhesive force of the adhesive agent layer, and in terms of easy availability.
The crosslinking agent contained in the adhesive composition (I-1) may be one kind only, or two or more kinds, and in the case of two or more kinds, the combination and ratio thereof may be arbitrarily selected.
The content of the crosslinking agent in the adhesive composition (I-1) is preferably 0.01 to 50 parts by mass, more preferably 0.1 to 20 parts by mass, and particularly preferably 0.3 to 15 parts by mass, relative to 100 parts by mass of the content of the adhesive resin (I-1 a).
[ photopolymerization initiator ]
The adhesive composition (I-1) may further contain a photopolymerization initiator. The adhesive composition (I-1) containing a photopolymerization initiator is sufficiently cured even when irradiated with relatively low-energy radiation such as ultraviolet light.
Examples of the photopolymerization initiator include benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, and benzoin dimethyl ketal; acetophenone compounds such as acetophenone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, and 2, 2-dimethoxy-1, 2-diphenylethan-1-one; acylphosphine oxide compounds such as phenylbis (2,4, 6-trimethylbenzoyl) phosphine oxide and 2,4, 6-trimethylbenzoyl diphenylphosphine oxide; sulfides such as benzyl phenyl sulfide and tetramethylthiuram monosulfide; α -ketol compounds such as 1-hydroxycyclohexyl phenyl ketone; azo compounds such as azobisisobutyronitrile; titanocene compounds such as titanocene; thioxanthone compounds such as thioxanthone; a peroxide compound; diketone compounds such as diacetyl; benzil (benzil); dibenzoyl; benzophenone; 2, 4-diethylthioxanthone; 1, 2-diphenylmethane; 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl ] propanone; 2-chloroanthraquinone, and the like.
Further, as the photopolymerization initiator, for example, quinone compounds such as 1-chloroanthraquinone; photosensitizers such as amines, and the like.
The photopolymerization initiator contained in the pressure-sensitive adhesive composition (I-1) may be only one kind, or two or more kinds, and in the case of two or more kinds, the combination and ratio thereof may be arbitrarily selected.
In the adhesive composition (I-1), the content of the photopolymerization initiator is preferably 0.01 to 20 parts by mass, more preferably 0.03 to 10 parts by mass, and particularly preferably 0.05 to 5 parts by mass, relative to 100 parts by mass of the content of the energy ray-curable compound.
[ other additives ]
The adhesive composition (I-1) may contain other additives not belonging to any of the above-mentioned components within a range not impairing the effects of the present invention.
Examples of the other additives include known additives such as antistatic agents, antioxidants, softeners (plasticizers), fillers (fillers), rust inhibitors, colorants (pigments and dyes), sensitizers, tackifiers, reaction retarders, crosslinking accelerators (catalysts), and interlayer migration inhibitors.
The reaction retarder is, for example, a component for suppressing the unintended crosslinking reaction of the adhesive composition (I-1) during storage due to the action of the catalyst mixed in the adhesive composition (I-1). Examples of the reaction retarder include a reaction retarder which forms a chelate complex (chelate complex) by a chelate compound corresponding to a catalyst, and more specifically, a reaction retarder having two or more carbonyl groups (-C (═ O) -) in one molecule.
The interlayer migration inhibitor is a component for inhibiting migration of a component contained in a layer adjacent to the adhesive agent layer, such as a film for forming a protective film, to the adhesive agent layer. The interlayer migration inhibitor may be the same component as the migration inhibitor, and for example, when the migration inhibitor is an epoxy resin in the film for forming the protective film, the same epoxy resin may be used.
The adhesive composition (I-1) may contain only one other additive, or may contain two or more other additives, and when two or more other additives are contained, the combination and ratio of these additives may be arbitrarily selected.
The content of the other additives in the adhesive composition (I-1) is not particularly limited, and may be appropriately selected depending on the kind thereof.
[ solvent ]
The adhesive composition (I-1) may contain a solvent. By containing the solvent, the applicability of the adhesive composition (I-1) to the surface to be coated is improved.
The solvent is preferably an organic solvent, and examples of the organic solvent include ketones such as methyl ethyl ketone and acetone; esters (carboxylic acid esters) such as ethyl acetate; ethers such as tetrahydrofuran and dioxane; aliphatic hydrocarbons such as cyclohexane and n-hexane; aromatic hydrocarbons such as toluene and xylene; alcohols such as 1-propanol and 2-propanol.
The solvent may be used as it is in the adhesive composition (I-1) without removing the solvent used in the production of the adhesive resin (I-1a) from the adhesive resin (I-1a), or a solvent which is the same as or different from the solvent used in the production of the adhesive resin (I-1a) may be added separately in the production of the adhesive composition (I-1).
The adhesive composition (I-1) may contain only one solvent, or may contain two or more solvents, and when two or more solvents are contained, the combination and ratio of the two or more solvents can be arbitrarily selected.
The content of the solvent in the adhesive composition (I-1) is not particularly limited, and may be appropriately adjusted.
< adhesive composition (I-2) >
As described above, the adhesive composition (I-2) contains the energy ray-curable adhesive resin (I-2a) in which an unsaturated group is introduced into the side chain of the non-energy ray-curable adhesive resin (I-1 a).
[ adhesive resin (I-2a) ]
The adhesive resin (I-2a) can be obtained, for example, by reacting an unsaturated group-containing compound having an energy ray-polymerizable unsaturated group with a functional group in the adhesive resin (I-1 a).
The unsaturated group-containing compound is a compound having a group capable of bonding to the adhesive resin (I-1a) by reacting with a functional group in the adhesive resin (I-1a), in addition to the energy ray-polymerizable unsaturated group.
Examples of the energy ray-polymerizable unsaturated group include a (meth) acryloyl group, a vinyl group (ethylene group), and an allyl group (2-propenyl group), and a (meth) acryloyl group is preferable.
Examples of the group capable of bonding to the functional group in the adhesive resin (I-1a) include an isocyanate group and a glycidyl group capable of bonding to a hydroxyl group or an amino group, and a hydroxyl group and an amino group capable of bonding to a carboxyl group or an epoxy group.
Examples of the unsaturated group-containing compound include (meth) acryloyloxyethyl isocyanate, (meth) acryloyl isocyanate, and glycidyl (meth) acrylate.
The adhesive resin (I-2a) contained in the adhesive composition (I-2) may be one type or two or more types, and when two or more types are used, the combination and ratio thereof may be arbitrarily selected.
In the adhesive composition (I-2), the content of the adhesive resin (I-2a) is preferably 5 to 99% by mass, more preferably 10 to 95% by mass, and particularly preferably 10 to 90% by mass, based on the total mass of the adhesive composition (I-2).
[ crosslinking agent ]
For example, when the acrylic polymer having a structural unit derived from a functional group-containing monomer, which is the same as that in the adhesive resin (I-1a), is used as the adhesive resin (I-2a), it is preferable that the adhesive composition (I-2) further contains a crosslinking agent.
The crosslinking agent in the adhesive composition (I-2) may be the same crosslinking agent as that in the adhesive composition (I-1).
The crosslinking agent contained in the adhesive composition (I-2) may be one kind only, or two or more kinds, and in the case of two or more kinds, the combination and ratio thereof may be arbitrarily selected.
In the adhesive composition (I-2), the content of the crosslinking agent is preferably 0.01 to 50 parts by mass, more preferably 0.1 to 20 parts by mass, and particularly preferably 0.3 to 15 parts by mass, relative to 100 parts by mass of the content of the adhesive resin (I-2 a).
[ photopolymerization initiator ]
The adhesive composition (I-2) may further contain a photopolymerization initiator. The adhesive composition (I-2) containing a photopolymerization initiator sufficiently undergoes a curing reaction even when irradiated with relatively low-energy radiation such as ultraviolet light.
The photopolymerization initiator in the adhesive composition (I-2) may be the same photopolymerization initiator as that in the adhesive composition (I-1).
The photopolymerization initiator contained in the pressure-sensitive adhesive composition (I-2) may be only one kind, or two or more kinds, and in the case of two or more kinds, the combination and ratio thereof may be arbitrarily selected.
The content of the photopolymerization initiator in the adhesive composition (I-2) is preferably 0.01 to 20 parts by mass, more preferably 0.03 to 10 parts by mass, and particularly preferably 0.05 to 5 parts by mass, relative to 100 parts by mass of the content of the adhesive resin (I-2 a).
[ other additives and solvents ]
The adhesive composition (I-2) may contain other additives not belonging to any of the above-mentioned components within a range not impairing the effects of the present invention.
Further, the adhesive composition (I-2) may also contain a solvent for the same purpose as in the case of the adhesive composition (I-1).
Examples of the other additive and the solvent in the adhesive composition (I-2) include other additives and solvents similar to those in the adhesive composition (I-1).
The other additives and solvents contained in the adhesive composition (I-2) may be one type or two or more types, and when two or more types are contained, the combination and ratio thereof may be arbitrarily selected.
The content of each of the other additives and the solvent in the adhesive composition (I-2) is not particularly limited, and may be appropriately selected depending on the kind thereof.
< adhesive composition (I-3) >
As described above, the adhesive composition (I-3) contains the adhesive resin (I-2a) and an energy ray-curable compound.
In the adhesive composition (I-3), the content of the adhesive resin (I-2a) is preferably 5 to 99% by mass, more preferably 10 to 95% by mass, and particularly preferably 15 to 90% by mass, based on the total mass of the adhesive composition (I-3).
[ energy ray-curable Compound ]
Examples of the energy ray-curable compound contained in the adhesive composition (I-3) include a monomer or oligomer having an energy ray-polymerizable unsaturated group and curable by irradiation with an energy ray, and examples of the energy ray-curable compound include the same energy ray-curable compounds as those contained in the adhesive composition (I-1).
The energy ray-curable compound contained in the adhesive composition (I-3) may be only one kind, or two or more kinds, and when two or more kinds are contained, the combination and ratio thereof may be arbitrarily selected.
The content of the energy ray-curable compound in the adhesive composition (I-3) is preferably 0.01 to 300 parts by mass, more preferably 0.03 to 200 parts by mass, and particularly preferably 0.05 to 100 parts by mass, relative to 100 parts by mass of the content of the adhesive resin (I-2 a).
[ photopolymerization initiator ]
The adhesive composition (I-3) may further contain a photopolymerization initiator. The adhesive composition (I-3) containing a photopolymerization initiator is sufficiently cured even when irradiated with relatively low-energy radiation such as ultraviolet light.
The photopolymerization initiator in the adhesive composition (I-3) may be the same photopolymerization initiator as that in the adhesive composition (I-1).
The photopolymerization initiator contained in the pressure-sensitive adhesive composition (I-3) may be only one kind, or two or more kinds, and in the case of two or more kinds, the combination and ratio thereof may be arbitrarily selected.
In the adhesive composition (I-3), the content of the photopolymerization initiator is preferably 0.01 to 20 parts by mass, more preferably 0.03 to 10 parts by mass, and particularly preferably 0.05 to 5 parts by mass, based on 100 parts by mass of the total content of the adhesive resin (I-2a) and the energy ray-curable compound.
[ other additives and solvents ]
The adhesive composition (I-3) may contain other additives not belonging to any of the above-mentioned components within a range not impairing the effects of the present invention.
Further, the adhesive composition (I-3) may also contain a solvent for the same purpose as in the case of the adhesive composition (I-1).
Examples of the other additive and the solvent in the adhesive composition (I-3) include other additives and solvents similar to those in the adhesive composition (I-1).
The adhesive composition (I-3) may contain only one type of other additive and solvent, or two or more types of other additives and solvents, and when two or more types are contained, the combination and ratio of these may be arbitrarily selected.
The content of each of the other additives and the solvent in the adhesive composition (I-3) is not particularly limited, and may be appropriately selected depending on the kind thereof.
< adhesive compositions other than the adhesive compositions (I-1) to (I-3) >
The adhesive composition (I-1), the adhesive composition (I-2) and the adhesive composition (I-3) have been mainly described so far, and the components described as the components contained therein can be similarly used for all adhesive compositions other than the three adhesive compositions (in the present specification, referred to as "adhesive compositions other than the adhesive compositions (I-1) to (I-3)").
Examples of the adhesive compositions other than the adhesive compositions (I-1) to (I-3) include energy ray-curable adhesive compositions and non-energy ray-curable adhesive compositions.
Examples of the non-energy ray-curable adhesive composition include an adhesive composition (I-4) containing a non-energy ray-curable adhesive resin (I-1a) such as an acrylic resin, a urethane resin, a rubber resin, a silicone resin, an epoxy resin, a polyvinyl ether, a polycarbonate, or an ester resin, and a non-energy ray-curable adhesive composition containing an acrylic resin is preferable.
The adhesive compositions other than the adhesive compositions (I-1) to (I-3) preferably contain one or more kinds of crosslinking agents, and the content thereof may be set to the same content as in the case of the adhesive composition (I-1) or the like.
< adhesive composition (I-4) >
A preferable adhesive composition (I-4) includes, for example, an adhesive composition containing the adhesive resin (I-1a) and a crosslinking agent.
[ adhesive resin (I-1a) ]
The adhesive resin (I-1a) in the adhesive composition (I-4) may be the same adhesive resin as the adhesive resin (I-1a) in the adhesive composition (I-1).
The adhesive resin (I-1a) contained in the adhesive composition (I-4) may be one type or two or more types, and when two or more types are used, the combination and ratio thereof may be arbitrarily selected.
In the adhesive composition (I-4), the content of the adhesive resin (I-1a) is preferably 5 to 99% by mass, more preferably 10 to 95% by mass, and particularly preferably 15 to 90% by mass, based on the total mass of the adhesive composition (I-4).
[ crosslinking agent ]
When the acrylic polymer having a structural unit derived from a functional group-containing monomer in addition to a structural unit derived from an alkyl (meth) acrylate is used as the adhesive resin (I-1a), the adhesive composition (I-4) preferably further contains a crosslinking agent.
The crosslinking agent in the adhesive composition (I-4) may be the same crosslinking agent as that in the adhesive composition (I-1).
The crosslinking agent contained in the adhesive composition (I-4) may be one kind only, or two or more kinds, and in the case of two or more kinds, the combination and ratio thereof may be arbitrarily selected.
The content of the crosslinking agent in the adhesive composition (I-4) is preferably 0.01 to 50 parts by mass, more preferably 0.1 to 47 parts by mass, and particularly preferably 0.3 to 44 parts by mass, relative to 100 parts by mass of the content of the adhesive resin (I-1 a).
[ other additives and solvents ]
The adhesive composition (I-4) may contain other additives not belonging to any of the above-mentioned components within a range not impairing the effects of the present invention.
Further, the adhesive composition (I-4) may also contain a solvent for the same purpose as in the case of the adhesive composition (I-1).
Examples of the other additive and the solvent in the adhesive composition (I-4) include other additives and solvents similar to those in the adhesive composition (I-1).
The adhesive composition (I-4) may contain only one type of other additive and solvent, or two or more types of other additives and solvents, and when two or more types are contained, the combination and ratio of these additives and solvents can be arbitrarily selected.
The content of each of the other additives and the solvent in the adhesive composition (I-4) is not particularly limited, and may be appropriately selected depending on the kind thereof.
When the protective film-forming film described later is energy ray-curable, the adhesive layer is preferably non-energy ray-curable. This is because, if the adhesive layer is energy ray-curable, simultaneous curing of the adhesive layer cannot be suppressed when the protective film-forming film is cured by irradiation with an energy ray. If the adhesive layer and the protective film-forming film are cured simultaneously, a cured product of the protective film-forming film and the adhesive layer may stick to each other to such an extent that they cannot be peeled off from each other at the interface therebetween. In this case, it is difficult to peel the semiconductor chip having the protective film (i.e., the semiconductor chip with the protective film) which is a cured product having the film for forming the protective film on the back surface from the support sheet having the cured product of the adhesive layer, and the semiconductor chip having the protective film cannot be picked up normally. If the adhesive layer is non-energy ray curable, such a problem can be avoided reliably, and the semiconductor chip with the protective film can be picked up more easily.
Here, although the effect when the adhesive agent layer is non-energy ray-curable is described, even if the layer of the support sheet that is in direct contact with the film for forming a protective film is a layer other than the adhesive agent layer, the same effect is exhibited as long as the layer is non-energy ray-curable.
Preparation method of adhesive composition
The adhesive compositions other than the adhesive compositions (I-1) to (I-3), such as the adhesive compositions (I-1) to (I-3) and the adhesive composition (I-4), can be obtained by blending the components constituting the adhesive composition, that is, the adhesive and, if necessary, the components other than the adhesive.
The order of addition of the components in blending is not particularly limited, and two or more components may be added simultaneously.
When the solvent is used, the solvent may be mixed with any of the components other than the solvent to dilute the components in advance, or the solvent may be mixed with the components without diluting any of the components other than the solvent to use.
When blending, the method for mixing the components is not particularly limited, and may be appropriately selected from the following known methods: a method of mixing by rotating a stirrer, a stirring blade, or the like; a method of mixing using a mixer; a method of mixing by applying ultrasonic waves, and the like.
The temperature and time for adding and mixing the components are not particularly limited and may be appropriately adjusted as long as the components are not deteriorated, but the temperature is preferably 15 to 30 ℃.
O back antistatic layer
The back antistatic layer is sheet-shaped or film-shaped and contains an antistatic agent.
The back antistatic layer may also contain a resin in addition to the antistatic agent.
The back antistatic layer may be composed of one layer (single layer) or a plurality of layers of two or more layers, and when composed of a plurality of layers, these plurality of layers may be the same as or different from each other, and the combination of these plurality of layers is not particularly limited.
The thickness of the back antistatic layer is preferably 200nm or less, more preferably 180nm or less, and may be, for example, 100nm or less. Since the back surface antistatic layer having a thickness of 200nm or less can maintain sufficient antistatic performance and the amount of the antistatic agent used can be reduced, the cost of the composite sheet for forming a protective film provided with the back surface antistatic layer can be reduced. Further, when the thickness of the back surface antistatic layer is 100nm or less, in addition to the above-described effects, an effect of suppressing the variation in the characteristics of the composite sheet for forming a protective film due to the provision of the back surface antistatic layer to the minimum can be obtained. Examples of the characteristic include expandability.
Here, the "thickness of the back surface antistatic layer" refers to the thickness of the entire back surface antistatic layer, and for example, the thickness of the back surface antistatic layer composed of a plurality of layers refers to the total thickness of all the layers constituting the back surface antistatic layer.
The thickness of the back antistatic layer is preferably 10nm or more, and may be, for example, 20nm or more, 30nm or more, 40nm or more, or 65nm or more. The back antistatic layer with the thickness more than the lower limit value is easier to form, and the structure is more stable.
The thickness of the back antistatic layer can be appropriately adjusted within a range set by arbitrarily combining the above preferable lower limit value and upper limit value. For example, in one embodiment, the thickness of the back antistatic layer is preferably 10 to 200nm, and may be, for example, any one of 20 to 200nm, 30 to 200nm, 40 to 180nm, and 65 to 100 nm. These ranges are but one example of the thickness of the backside antistatic layer.
In order to recognize laser printing of the protective film through the support sheet, the back surface antistatic layer is preferably transparent.
When the protective film-forming film has energy ray curability, the back antistatic layer preferably transmits energy rays.
Antistatic composition (VI-1))
The back antistatic layer can be formed using the antistatic composition (VI-1) containing the antistatic agent. For example, the antistatic composition (VI-1) can be applied to the surface of a back antistatic layer to be formed, and dried as necessary to form a back antistatic layer on the target portion. The ratio of the contents of the components that do not vaporize at ordinary temperature to each other in the antistatic composition (VI-1) is generally the same as the ratio of the contents of the components to each other in the back antistatic layer.
A more specific method of forming the back antistatic layer will be described in detail later together with methods of forming other layers.
The antistatic composition (VI-1) may be applied by a known method, and for example, the same method as in the case of the adhesive composition can be used.
When a back antistatic layer is provided on a substrate, for example, the back antistatic layer may be laminated on the substrate by applying the antistatic composition (VI-1) on the substrate and drying it as necessary. In addition, when a back surface antistatic layer is provided on the base material, for example, the back surface antistatic layer may be laminated on the base material by applying the antistatic composition (VI-1) to a release film and drying it as necessary to form the back surface antistatic layer on the release film and bonding the exposed surface of the back surface antistatic layer to one surface of the base material. The release film in this case may be removed at any time during the production process or the use process of the composite sheet for forming a protective film.
In addition, as the surface of the base material on the side where the back antistatic layer is formed, either a rough surface or a smooth surface can be selected. From the viewpoint of improving adhesion between the base material and the back surface antistatic layer, or from the viewpoint of improving total light transmittance or haze of the support sheet, it is preferable to select a surface of the base material on the side where the back surface antistatic layer is formed, the surface having a surface roughness rougher than that of the base material on the side where the back surface antistatic layer is not formed.
In addition, from the viewpoint of the thin film thickness and the ability to maintain the smoothness of the antistatic layer surface, it is preferable to select a surface of the substrate on the side where the back antistatic layer is formed, the surface having a surface roughness smoother than that of the substrate on the side where the back antistatic layer is not formed.
The drying conditions of the antistatic composition (VI-1) are not particularly limited, but when the antistatic composition (VI-1) contains a solvent described later, it is preferably dried by heating. The antistatic composition (VI-1) containing a solvent is preferably dried at 40 to 130 ℃ for 10 seconds to 5 minutes, for example.
The antistatic composition (VI-1) may contain the resin in addition to the antistatic agent.
[ antistatic agent ]
The antistatic agent may be a known antistatic agent such as a conductive compound, and is not particularly limited, but is preferably an antistatic agent which is not colored. The antistatic agent may be, for example, any of a low molecular compound and a high molecular compound (in other words, an oligomer or a polymer).
Examples of the low-molecular-weight compound in the antistatic agent include various ionic liquids.
Examples of the ionic liquid include known ionic liquids such as a pyrimidinium salt, a pyridinium salt, a piperidinium salt, a pyrrolidinium salt, an imidazolium salt, a morpholinium salt, a sulfonium salt, a phosphonium salt, and an ammonium salt.
Examples of the polymer compound in the antistatic agent include poly (3, 4-ethylenedioxythiophene)/polystyrene sulfonic acid (in the present specification, sometimes referred to as "PEDOT/PSS"), carbon nanotubes, and the like.
The antistatic agent contained in the antistatic composition (VI-1) may be one kind or two or more kinds, and when two or more kinds are contained, the combination and ratio thereof may be arbitrarily selected.
In the antistatic composition (VI-1), the proportion of the content of the antistatic agent to the total content of all the components except the solvent (i.e., the proportion of the content of the antistatic agent in the back antistatic layer to the total mass of the back antistatic layer) may be, for example, in any range of 0.1 to 30 mass% and 0.5 to 15 mass%. When the ratio is equal to or higher than the lower limit value, the effect of suppressing peeling electrification of the composite sheet for forming a protective film is increased, and as a result, the effect of suppressing the incorporation of foreign matter between the film for forming a protective film and the semiconductor wafer is increased. By setting the ratio to the upper limit value or less, the strength of the back antistatic layer becomes higher.
[ resin ]
The resin contained in the antistatic composition (VI-1) and the back antistatic layer may be either curable or non-curable, and in the case of being curable, may be either energy ray-curable or thermosetting.
Examples of the preferable resin include resins that function as binder resins.
More specifically, the resin includes, for example, an acrylic resin, and preferably an energy ray-curable acrylic resin.
Examples of the acrylic resin in the antistatic composition (VI-1) and the back antistatic layer include the same resins as those in the adhesive layer. Examples of the energy ray-curable acrylic resin in the antistatic composition (VI-1) and the back antistatic layer include the same energy ray-curable acrylic resin as the adhesive resin (I-2a) in the adhesive layer.
The resin contained in the antistatic composition (VI-1) and the back antistatic layer may be one kind or two or more kinds, and when two or more kinds are contained, the combination and ratio thereof may be arbitrarily selected.
In the antistatic composition (VI-1), the proportion of the content of the resin with respect to the total content of all the components except the solvent (i.e., the proportion of the content of the resin in the back antistatic layer with respect to the total mass of the back antistatic layer) may be, for example, any one of the ranges of 30 to 99.9 mass%, 35 to 98 mass%, 60 to 98 mass%, and 85 to 98 mass%. By making the ratio the lower limit value or more, the strength of the back antistatic layer becomes further high. By making the ratio the upper limit value or less, the content of the antistatic agent of the antistatic layer can be further increased.
[ energy ray-curable compound and photopolymerization initiator ]
When the antistatic composition (VI-1) contains the resin curable with energy ray, an energy ray-curable compound may be contained.
Further, when the antistatic composition (VI-1) contains the resin curable with energy rays, a photopolymerization initiator may be contained in order to efficiently carry out the polymerization reaction of the resin.
Examples of the energy ray-curable compound and the photopolymerization initiator contained in the antistatic composition (VI-1) include the same energy ray-curable compound and photopolymerization initiator as those contained in the adhesive composition (I-1).
The energy ray-curable compound and the photopolymerization initiator contained in the antistatic composition (VI-1) may be each one kind or two or more kinds, and when two or more kinds are contained, the combination and ratio thereof may be arbitrarily selected.
The content of the energy ray-curable compound and the photopolymerization initiator in the antistatic composition (VI-1) are not particularly limited, and may be appropriately selected depending on the kind of the resin, the energy ray-curable compound, or the photopolymerization initiator.
[ other additives and solvents ]
The antistatic composition (VI-1) may contain other additives not belonging to any of the above-mentioned components within a range not impairing the effects of the present invention.
Further, the antistatic composition (VI-1) may also contain a solvent for the same purpose as in the case of the above adhesive composition (I-1).
Examples of the other additives and solvents contained in the antistatic composition (VI-1) include the same other additives and solvents as those contained in the adhesive composition (I-1) (except for the antistatic agent). Further, as the other additives contained in the antistatic composition (VI-1), in addition to the above-mentioned other additives, an emulsifier can be mentioned. Further, as the solvent contained in the antistatic composition (VI-1), other alcohols such as ethanol; and alkoxyalcohols such as 2-methoxyethanol (ethylene glycol monomethyl ether), 2-ethoxyethanol (ethylene glycol monoethyl ether), and 1-methoxy-2-propanol (propylene glycol monomethyl ether).
The other additives and solvents contained in the antistatic composition (VI-1) may be one or more, and when two or more are used, the combination and ratio thereof may be arbitrarily selected.
The contents of other additives and solvents in the antistatic composition (VI-1) are not particularly limited, and may be appropriately selected depending on the kind thereof.
Preparation of antistatic composition (VI-1)
The antistatic composition (VI-1) can be obtained by blending the respective components for constituting the antistatic composition (VI-1), that is, by blending the antistatic agent with components other than the antistatic agent, etc., which are contained as required.
The antistatic composition (VI-1) can be prepared by the same method as the above adhesive composition except that the blending components are different.
O surface antistatic layer
The front surface antistatic layer is disposed at a position different from that of the back surface antistatic layer in the protective film-forming composite sheet, but has the same constitution as the back surface antistatic layer. For example, the surface antistatic layer can be formed using the antistatic composition (VI-1) by the same method as the method for forming the back antistatic layer described previously. Therefore, detailed description of the surface antistatic layer is omitted.
When the composite sheet for forming a protective film includes both the front surface antistatic layer and the back surface antistatic layer, these front surface antistatic layer and back surface antistatic layer may be the same or different from each other.
In addition, as the surface of the substrate on the side where the surface antistatic layer is formed, any of a rough surface and a smooth surface can be selected. From the viewpoint of improving adhesion between the base material and the surface antistatic layer, or from the viewpoint of improving total light transmittance or haze of the support sheet, it is preferable to select a surface of the base material on the side where the surface antistatic layer is formed, the surface having a surface roughness rougher than that of the base material on the side where the surface antistatic layer is not formed.
In addition, from the viewpoint of the thin film thickness and the ability to maintain the smoothness of the antistatic layer surface, it is preferable to select a surface having a surface roughness smoother than that of the substrate on the side on which the surface antistatic layer is not formed.
Middle layer very high
The intermediate layer is sheet-shaped or film-shaped.
As described above, a preferable intermediate layer is a peeling property improving layer having one surface subjected to a peeling treatment. The peelability improving layer may be a peelability improving layer including a plurality of layers, the peelability improving layer including a resin layer and a release treatment layer formed on the resin layer. In the composite sheet for forming a protective film, the peeling property improving layer is disposed so that the peeling treatment layer faces the protective film forming film side.
The resin layer in the releasability-improving layer can be produced by molding a resin composition containing a resin.
The releasability-improving layer can be produced by subjecting one surface of the resin layer to a release treatment.
The resin layer can be peeled off using various known peeling agents such as alkyd, silicone, fluorine, unsaturated polyester, polyolefin, wax, and the like.
The releasing agent is preferably an alkyd type, silicone type or fluorine type releasing agent in terms of heat resistance.
The resin used as a constituent material of the resin layer may be appropriately selected according to the purpose, and is not particularly limited.
Preferable examples of the resin include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), Polyethylene (PE), and polypropylene (PP).
The intermediate layer may be composed of one layer (single layer) or a plurality of layers of two or more layers regardless of whether it is a peeling property improving layer, and in the case of being composed of a plurality of layers, these plurality of layers may be the same as or different from each other, and the combination of these plurality of layers is not particularly limited. For example, when the intermediate layer is a release property improving layer, the resin layer and the release treatment layer may be each composed of one layer (single layer) or may be composed of a plurality of layers of two or more layers.
The thickness of the intermediate layer may be appropriately adjusted depending on the kind thereof, and is not particularly limited.
For example, the thickness of the release property improving layer (the total thickness of the resin layer and the release treatment layer) is preferably 10 to 2000nm, more preferably 25 to 1500nm, and particularly preferably 50 to 1200 nm. When the thickness of the peelability improvement layer is equal to or greater than the lower limit value, the effect of the peelability improvement layer becomes more remarkable, and the effect of suppressing breakage such as cutting of the peelability improvement layer becomes higher. When the thickness of the peeling property improving layer is set to the upper limit or less, a force of pushing up the semiconductor chip with the protective film or the semiconductor chip with the film for forming the protective film, which will be described later, is easily transmitted to the chip when the semiconductor chip or the semiconductor chip with the film for forming the protective film is picked up, and the semiconductor chip can be picked up more easily.
The intermediate layer may be transparent or opaque, and may be colored according to the purpose.
For example, when the protective film-forming film has energy ray curability, the intermediate layer preferably transmits energy rays.
For example, in order to optically inspect the film for forming the protective film in the composite sheet for forming the protective film through the intermediate layer, the intermediate layer is preferably transparent.
Protective film forming film
The protective film-forming film becomes a protective film by curing. The protective film is used to protect the back surface of the semiconductor wafer or semiconductor chip (in other words, the surface opposite to the electrode formation surface). The protective film-forming film is soft and can be easily attached to an object to be attached.
In the present specification, the "protective film-forming film" refers to a film before curing, and the "protective film" refers to a film obtained by curing the protective film-forming film.
In the present specification, even after the protective film-forming film is cured, the laminated structure is referred to as a "protective film-forming composite sheet" as long as the laminated structure of the support sheet and the cured product of the protective film-forming film (in other words, the support sheet and the protective film) is maintained.
The protective film-forming film may be either thermosetting or energy-ray-curable, and may or may not have both thermosetting and energy-ray-curable properties. When the protective film-forming film does not have curability, the protective film is considered to be formed from the protective film-forming film at the stage when the protective film-forming composite sheet is attached to the semiconductor wafer via the protective film-forming film, which will be described later.
The protective film-forming film may be composed of one layer (single layer) or a plurality of two or more layers, regardless of whether the protective film-forming film has curability or not, and in the case where the protective film-forming film is curability, regardless of whether the protective film-forming film is thermosetting or energy ray-curable. When the protective film-forming film is composed of a plurality of layers, these plurality of layers may be the same as each other or different from each other, and the combination of these plurality of layers is not particularly limited.
The thickness of the protective film-forming film is preferably 1 to 100 μm, more preferably 3 to 80 μm, and particularly preferably 5 to 60 μm, regardless of whether the protective film-forming film has curability or not, and when the protective film-forming film is curability, regardless of whether the protective film-forming film is thermosetting or energy ray-curable. When the thickness of the protective film forming film is not less than the lower limit value, a protective film having higher protective performance can be formed. Further, by setting the thickness of the protective film-forming film to the upper limit or less, the thickness is prevented from becoming excessively thick.
The "thickness of the protective film-forming film" refers to the thickness of the entire protective film-forming film, and for example, the thickness of the protective film-forming film composed of a plurality of layers refers to the total thickness of all the layers constituting the protective film-forming film.
Composition for Forming protective film
The protective film-forming film can be formed using a protective film-forming composition containing the constituent material thereof. For example, the protective film-forming film can be formed by applying the protective film-forming composition to the surface to be formed, and drying the composition as needed. The ratio of the contents of the components that do not vaporize at ordinary temperature in the protective film-forming composition to each other is generally the same as the ratio of the contents of the components to each other in the protective film-forming film.
The film for forming a thermosetting protective film can be formed using the composition for forming a thermosetting protective film, and the film for forming an energy ray-curable protective film can be formed using the composition for forming an energy ray-curable protective film. In the present specification, when the protective film-forming film has both properties of thermosetting and energy ray-curable properties, the protective film-forming film is regarded as a thermosetting film when the contribution of the thermosetting of the protective film-forming film to the formation of the protective film is larger than the contribution of the energy ray-curing. In contrast, in the case where the energy ray curing of the protective film forming film contributes to the formation of the protective film more than the heat curing, the protective film forming film is regarded as an energy ray-curable film.
The coating of the protective film-forming composition can be performed, for example, by the same method as the coating of the adhesive composition described above.
The drying conditions of the protective film-forming composition are not particularly limited, regardless of whether the protective film-forming film has curability or not, and in the case where the protective film-forming film is curable, regardless of whether the protective film-forming film is thermosetting or energy ray-curable. However, when the composition for forming a protective film contains a solvent described later, it is preferably dried by heating. The solvent-containing composition for forming a protective film is preferably dried by heating at 70 to 130 ℃ for 10 seconds to 5 minutes, for example. Among these, the thermosetting protective film-forming composition is preferably dried by heating so as not to cure the composition itself and the thermosetting protective film-forming film formed from the composition.
The film for forming a thermosetting protective film and the film for forming an energy ray-curable protective film are described below in this order.
Film for forming thermosetting protective film
The curing conditions for forming the protective film by attaching the thermosetting protective film-forming film to the back surface of the semiconductor wafer and thermally curing the film are not particularly limited as long as the protective film has a curing degree to such an extent that the function thereof is sufficiently exhibited, and may be appropriately selected depending on the kind of the thermosetting protective film-forming film.
For example, the heating temperature for thermosetting the film for forming a thermosetting protective film is preferably 100 to 200 ℃, more preferably 110 to 180 ℃, and particularly preferably 120 to 170 ℃. The heating time during the heat curing is preferably 0.5 to 5 hours, more preferably 0.5 to 3 hours, and particularly preferably 1 to 2 hours.
Examples of a preferable thermosetting protective film-forming film include a thermosetting protective film-forming film containing a polymer component (a) and a thermosetting component (B). The polymer component (a) is a component obtained by polymerization of a polymerizable compound. The thermosetting component (B) is a component capable of undergoing a curing (polymerization) reaction by using heat as reaction inducing agent. The polymerization reaction in the present specification also includes a polycondensation reaction.
< composition for Forming thermosetting protective film (III-1) >
Examples of a preferable thermosetting protective film-forming composition include a thermosetting protective film-forming composition (III-1) (in the present specification, it may be abbreviated as "composition (III-1)") containing the polymer component (A) and the thermosetting component (B).
[ Polymer component (A) ]
The polymer component (a) is a component for imparting film formability, flexibility, and the like to the thermosetting protective film-forming film.
The polymer component (A) contained in the composition (III-1) and the film for forming a thermosetting protective film may be one type or two or more types, and when two or more types are contained, the combination and ratio thereof may be arbitrarily selected.
Examples of the polymer component (a) include acrylic resins, polyesters, urethane resins, acrylic urethane resins, silicone resins, rubber resins, phenoxy resins, thermosetting polyimides, and the like, and acrylic resins are preferred.
As the acrylic resin in the polymer component (a), a known acrylic polymer can be mentioned.
The weight average molecular weight (Mw) of the acrylic resin is preferably 10000 to 2000000, more preferably 100000 to 1500000. When the weight average molecular weight of the acrylic resin is not less than the lower limit, the shape stability (stability with time during storage) of the film for forming a thermosetting protective film is increased. Further, by setting the weight average molecular weight of the acrylic resin to be not more than the upper limit value, the film for forming a thermosetting protective film can easily follow the uneven surface of the adherend, and generation of voids (void) and the like between the adherend and the film for forming a thermosetting protective film can be further suppressed.
In addition, in the present specification, unless otherwise specified, "weight average molecular weight" means a polystyrene equivalent value measured by a Gel Permeation Chromatography (GPC) method.
The glass transition temperature (Tg) of the acrylic resin is preferably-60 to 70 ℃, more preferably-30 to 50 ℃. When the Tg of the acrylic resin is not less than the lower limit, for example, the adhesion between the cured product of the protective film-forming film and the supporting sheet is suppressed, and the releasability of the supporting sheet is appropriately improved. When the Tg of the acrylic resin is not more than the upper limit, the adhesive strength between the thermosetting protective film-forming film and the cured product thereof and the adherend is increased.
The Tg of the resin in the present specification can be obtained by, for example, not being limited to an acrylic resin: the inflection point was confirmed by changing the temperature of the object to be measured between-70 ℃ and 150 ℃ with the temperature rising rate or the temperature lowering rate set at 10 ℃/min using a Differential Scanning Calorimeter (DSC).
Examples of the acrylic resin include polymers of one or two or more kinds of (meth) acrylic acid esters; and copolymers of two or more monomers selected from (meth) acrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene, and N-methylolacrylamide.
In the present specification, "(meth) acrylic acid" is a concept including both "acrylic acid" and "methacrylic acid". Similar terms to those of (meth) acrylic acid are also the same, and for example, "(meth) acryloyl" is a concept including both "acryloyl" and "methacryloyl",
"(meth) acrylate" is a concept that includes both "acrylate" and "methacrylate".
Examples of the (meth) acrylic ester constituting the acrylic resin include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-octyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, dodecyl (meth) acrylate, and the like, Alkyl (meth) acrylates having a chain structure in which the alkyl group constituting the alkyl ester is 1 to 18 carbon atoms, such as tetradecyl (meth) acrylate (myristyl (meth) acrylate), pentadecyl (meth) acrylate, hexadecyl (meth) acrylate (palmityl (meth) acrylate), heptadecyl (meth) acrylate, and octadecyl (meth) acrylate (stearyl (meth) acrylate);
cycloalkyl (meth) acrylates such as isobornyl (meth) acrylate and dicyclopentanyl (meth) acrylate;
aralkyl (meth) acrylates such as benzyl (meth) acrylate;
cycloalkenyl (meth) acrylates such as dicyclopentenyl (meth) acrylate;
cycloalkenyloxyalkyl (meth) acrylates such as dicyclopentenyloxyethyl (meth) acrylate;
(meth) acrylic acid imide;
glycidyl group-containing (meth) acrylates such as glycidyl (meth) acrylate;
hydroxyl group-containing (meth) acrylates such as hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate;
and substituted amino group-containing (meth) acrylates such as N-methylaminoethyl (meth) acrylate. The "substituted amino group" refers to a group in which one or two hydrogen atoms of an amino group are substituted with a group other than a hydrogen atom.
The acrylic resin may be, for example, a resin obtained by copolymerizing one or more monomers selected from (meth) acrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene, N-methylolacrylamide, and the like, in addition to the (meth) acrylate.
The acrylic resin may be composed of only one monomer, or two or more monomers, and when two or more monomers are used, the combination and ratio of the monomers can be selected arbitrarily.
The acrylic resin may have a functional group capable of bonding with other compounds, such as a vinyl group, (meth) acryloyl group, amino group, hydroxyl group, carboxyl group, and isocyanate group. The functional group of the acrylic resin may be bonded to another compound via a crosslinking agent (F) described later, or may be directly bonded to another compound without via the crosslinking agent (F). Since the acrylic resin is bonded to another compound through the functional group, the reliability of the package obtained by using the composite sheet for forming a protective film tends to be improved.
In the present invention, as the polymer component (a), a thermoplastic resin other than an acrylic resin (hereinafter, may be simply abbreviated as "thermoplastic resin") may be used alone without using an acrylic resin, or an acrylic resin and a thermoplastic resin other than an acrylic resin may be used together. By using the thermoplastic resin, the releasability when the resin film is peeled from the support sheet is increased, or the film for forming the thermosetting protective film is made to easily follow the uneven surface of the adherend, and generation of a void or the like between the adherend and the film for forming the thermosetting protective film can be further suppressed.
The weight average molecular weight of the thermoplastic resin is preferably 1000 to 100000, and more preferably 3000 to 80000.
The glass transition temperature (Tg) of the thermoplastic resin is preferably-30 to 150 ℃, and more preferably-20 to 120 ℃.
Examples of the thermoplastic resin include polyester, polyurethane, phenoxy resin, polybutylene, polybutadiene, and polystyrene.
The thermoplastic resin contained in the composition (III-1) and the film for forming a thermosetting protective film may be one type or two or more types, and when two or more types are used, the combination and ratio thereof may be arbitrarily selected.
In the composition (III-1), the proportion of the content of the polymer component (a) to the total content of all components except the solvent (i.e., the proportion of the content of the polymer component (a) in the film for forming a thermosetting protective film to the total mass of the film for forming a thermosetting protective film) is preferably 5 to 85 mass%, more preferably 5 to 80 mass%, and may be, for example, any one of 5 to 65 mass%, 5 to 50 mass%, and 5 to 35 mass%, regardless of the kind of the polymer component (a).
The polymer component (A) may be a thermosetting component (B). In the present invention, when the composition (III-1) contains the above-mentioned components belonging to both the polymer component (A) and the thermosetting component (B), it is regarded that the composition (III-1) contains the polymer component (A) and the thermosetting component (B).
[ thermosetting component (B) ]
The thermosetting component (B) is a component for curing the film for forming a thermosetting protective film.
The thermosetting component (B) contained in the composition (III-1) and the film for forming a thermosetting protective film may be one kind or two or more kinds, and when two or more kinds are contained, the combination and ratio thereof may be arbitrarily selected.
Examples of the thermosetting component (B) include epoxy thermosetting resins, thermosetting polyimides, polyurethanes, unsaturated polyesters, silicone resins, and the like, and epoxy thermosetting resins are preferred.
(epoxy thermosetting resin)
The epoxy thermosetting resin is composed of an epoxy resin (B1) and a thermosetting agent (B2).
The epoxy thermosetting resin contained in the composition (III-1) and the film for forming a thermosetting protective film may be one kind or two or more kinds, and when two or more kinds are contained, the combination and ratio of these may be arbitrarily selected.
Epoxy resin (B1)
Examples of the epoxy resin (B1) include known epoxy resins, and examples thereof include polyfunctional epoxy resins, biphenyl compounds, bisphenol a diglycidyl ether and hydrogenated products thereof, o-cresol novolac epoxy resins, dicyclopentadiene epoxy resins, biphenyl epoxy resins, bisphenol a epoxy resins, bisphenol F epoxy resins, and epoxy resins having a phenylene skeleton.
As the epoxy resin (B1), an epoxy resin having an unsaturated hydrocarbon group can be used. The epoxy resin having an unsaturated hydrocarbon group has high compatibility with an acrylic resin, compared with an epoxy resin having no unsaturated hydrocarbon group. Therefore, by using an epoxy resin having an unsaturated hydrocarbon group, the reliability of a semiconductor chip with a resin film obtained by using the composite sheet for forming a protective film is improved.
Examples of the epoxy resin having an unsaturated hydrocarbon group include compounds in which a part of epoxy groups of a polyfunctional epoxy resin is converted into a group having an unsaturated hydrocarbon group. Such a compound can be obtained, for example, by addition reaction of (meth) acrylic acid or a derivative thereof with an epoxy group.
Examples of the epoxy resin having an unsaturated hydrocarbon group include compounds in which a group having an unsaturated hydrocarbon group is directly bonded to an aromatic ring or the like constituting the epoxy resin.
The unsaturated hydrocarbon group is a polymerizable unsaturated group, and specific examples thereof include an ethylene group (vinyl group), a 2-propenyl group (allyl group), (meth) acryloyl group, and (meth) acrylamido group, with acryloyl group being preferred.
The number average molecular weight of the epoxy resin (B1) is not particularly limited, but is preferably 300 to 30000, more preferably 300 to 10000, and particularly preferably 300 to 3000, in view of curability of the thermosetting protective film-forming film and strength and heat resistance of the resin film after curing.
In the present specification, unless otherwise specified, the number average molecular weight means a polystyrene equivalent value measured by a Gel Permeation Chromatography (GPC) method.
The epoxy equivalent of the epoxy resin (B1) is preferably 100 to 1000g/eq, more preferably 150 to 950 g/eq.
In the present specification, "epoxy equivalent" means the number of grams (g/eq) of an epoxy compound containing 1 gram equivalent of an epoxy group, which can be measured according to the method of JIS K7236: 2001.
The epoxy resin (B1) may be used alone or in combination of two or more, and when two or more are used simultaneously, the combination and ratio thereof may be arbitrarily selected.
Heat-curing agent (B2)
The thermosetting agent (B2) functions as a curing agent for the epoxy resin (B1).
Examples of the thermosetting agent (B2) include compounds having two or more functional groups reactive with epoxy groups in one molecule. Examples of the functional group include a phenolic hydroxyl group, an alcoholic hydroxyl group, an amino group, a carboxyl group, and a group obtained by anhydrizing an acid group, and the like, and a phenolic hydroxyl group, an amino group, or a group obtained by anhydrizing an acid group are preferable, and a phenolic hydroxyl group or an amino group is more preferable.
Examples of the phenol curing agent having a phenolic hydroxyl group in the heat curing agent (B2) include polyfunctional phenol resins, biphenol, novolak-type phenol resins, dicyclopentadiene-type phenol resins, and aralkyl-type phenol resins.
Examples of the amine-based curing agent having an amino group in the thermosetting agent (B2) include dicyandiamide.
The thermosetting agent (B2) may have an unsaturated hydrocarbon group.
Examples of the unsaturated hydrocarbon group-containing thermosetting agent (B2) include a compound in which a part of the hydroxyl groups of the phenol resin is substituted with an unsaturated hydrocarbon group, and a compound in which an unsaturated hydrocarbon group-containing group is directly bonded to an aromatic ring of the phenol resin.
The unsaturated hydrocarbon group in the thermosetting agent (B2) is the same as the unsaturated hydrocarbon group in the above-mentioned epoxy resin having an unsaturated hydrocarbon group.
When a phenol-based curing agent is used as the thermosetting agent (B2), the softening point or glass transition temperature of the thermosetting agent (B2) is preferably high from the point of improving the peelability when the protective film is peeled from the support sheet.
Among the heat curing agents (B2), for example, the number average molecular weight of the resin component such as a polyfunctional phenol resin, a novolak phenol resin, a dicyclopentadiene phenol resin, an aralkyl phenol resin is preferably 300 to 30000, more preferably 400 to 10000, and particularly preferably 500 to 3000.
In the thermosetting agent (B2), the molecular weight of the non-resin component such as biphenol and dicyandiamide is not particularly limited, and is preferably 60 to 500, for example.
The heat-curing agent (B2) may be used alone or in combination of two or more, and when two or more are used simultaneously, the combination and ratio thereof may be arbitrarily selected.
The content of the thermosetting agent (B2) in the composition (III-1) and the film for forming a thermosetting protective film is preferably 0.1 to 500 parts by mass, more preferably 1 to 200 parts by mass, and may be, for example, any one of 1 to 100 parts by mass, 1 to 50 parts by mass, 1 to 25 parts by mass, and 1 to 10 parts by mass, based on 100 parts by mass of the content of the epoxy resin (B1). By setting the content of the thermosetting agent (B2) to the lower limit or more, it becomes easier to cure the thermosetting protective film-forming film. When the content of the thermosetting agent (B2) is not more than the upper limit, the moisture absorption rate of the thermosetting protective film-forming film is reduced, and the reliability of the package obtained by using the composite sheet for forming a protective film is further improved.
In the composition (III-1) and the film for forming a thermosetting protective film, the content of the thermosetting component (B) (for example, the total content of the epoxy resin (B1) and the thermosetting agent (B2)) is preferably 20 to 500 parts by mass, more preferably 25 to 300 parts by mass, still more preferably 30 to 150 parts by mass, and may be, for example, 35 to 100 parts by mass or 40 to 80 parts by mass, based on 100 parts by mass of the content of the polymer component (A). When the content of the thermosetting component (B) is in the above range, for example, the adhesion between the cured product of the protective film-forming film and the supporting sheet is suppressed, and the releasability of the supporting sheet is improved.
[ curing Accelerator (C) ]
The composition (III-1) and the film for forming a thermosetting protective film may contain a curing accelerator (C). The curing accelerator (C) is a component for adjusting the curing speed of the composition (III-1).
Examples of the preferable curing accelerator (C) include tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris (dimethylaminomethyl) phenol; imidazoles (imidazole in which one or more hydrogen atoms are replaced with a group other than a hydrogen atom) such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4, 5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole; organic phosphines such as tributylphosphine, diphenylphosphine, and triphenylphosphine (phosphines in which one or more hydrogen atoms are substituted with an organic group); tetraphenylboron salts such as tetraphenylphosphonium tetraphenylphosphonate and triphenylphosphine tetraphenylboronate.
The curing accelerator (C) contained in the composition (III-1) and the film for forming a thermosetting protective film may be one kind or two or more kinds, and when two or more kinds are contained, the combination and ratio thereof may be arbitrarily selected.
When the curing accelerator (C) is used, the content of the curing accelerator (C) is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 7 parts by mass, based on 100 parts by mass of the thermosetting component (B) in the composition (III-1) and the film for forming a thermosetting protective film. By setting the content of the curing accelerator (C) to the lower limit or more, the effect of using the curing accelerator (C) can be more remarkably obtained. When the content of the curing accelerator (C) is not more than the above upper limit, for example, the effect of suppressing the occurrence of segregation due to the highly polar curing accelerator (C) moving to the side of the adhesive interface with the adherend in the film for forming a thermosetting protective film under high temperature and high humidity conditions becomes high. As a result, the reliability of the semiconductor chip with the protective film obtained by using the composite sheet for forming a protective film is further improved.
[ Filler (D) ]
The composition (III-1) and the film for forming a thermosetting protective film may contain a filler (D). By incorporating the filler (D) into the thermosetting protective film-forming film, it becomes easy to adjust the thermal expansion coefficient of the protective film obtained by curing the thermosetting protective film-forming film, and by optimizing the thermal expansion coefficient with respect to the object to be protected, the reliability of the semiconductor chip with the protective film obtained by using the composite sheet for protecting film formation is further improved. Further, by incorporating the filler (D) into the thermosetting protective film-forming film, the moisture absorption rate of the protective film can be reduced, and the heat dissipation can be improved.
The filler (D) may be any of an organic filler and an inorganic filler, and is preferably an inorganic filler.
Examples of preferable inorganic fillers include powders of silica, alumina, talc, calcium carbonate, titanium white, red iron oxide, silicon carbide, boron nitride, and the like; beads obtained by spheroidizing these inorganic fillers; surface modifications of these inorganic filler materials; single crystal fibers of these inorganic filler materials; glass fibers, and the like.
Among them, the inorganic filler is preferably silica or alumina, and more preferably silica.
The filler (D) contained in the composition (III-1) and the film for forming a thermosetting protective film may be one kind or two or more kinds, and when two or more kinds are contained, the combination and ratio thereof may be arbitrarily selected.
In the composition (III-1), the proportion of the content of the filler (D) relative to the total content of all the components except the solvent (i.e., the proportion of the content of the filler (D) in the film for forming a thermosetting protective film relative to the total mass of the film for forming a thermosetting protective film) is preferably 5 to 80% by mass, more preferably 10 to 70% by mass, and may be, for example, any one of 20 to 65% by mass, 30 to 65% by mass, and 40 to 65% by mass. By making the ratio within the above range, the adjustment of the thermal expansion coefficient of the protective film described above becomes easier.
[ coupling agent (E) ]
The composition (III-1) and the film for forming a thermosetting protective film may contain a coupling agent (E). By using a coupling agent having a functional group capable of reacting with an inorganic compound or an organic compound as the coupling agent (E), the adhesiveness and adhesion of the thermosetting protective film-forming film to an adherend can be improved. Further, by using the coupling agent (E), the cured product of the thermosetting protective film-forming film has high water resistance without impairing heat resistance.
The coupling agent (E) is preferably a compound having a functional group capable of reacting with a functional group of the polymer component (a), the thermosetting component (B), or the like, and more preferably a silane coupling agent.
Examples of the preferable silane coupling agent include 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxymethyldiethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3- (2-aminoethylamino) propyltrimethoxysilane, 3- (2-aminoethylamino) propylmethyldiethoxysilane, 3- (phenylamino) propyltrimethoxysilane, 3-anilinopropyltrimethoxysilane, 3-ureopropyltriethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, and the like, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, bis (3-triethoxysilylpropyl) tetrasulfide, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, imidazolesilane and the like.
The coupling agent (E) contained in the composition (III-1) and the film for forming a thermosetting protective film may be one kind or two or more kinds, and when two or more kinds are contained, the combination and ratio thereof may be arbitrarily selected.
When the coupling agent (E) is used, the content of the coupling agent (E) in the composition (III-1) and the film for forming a thermosetting protective film is preferably 0.03 to 20 parts by mass, more preferably 0.05 to 10 parts by mass, and particularly preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the total content of the polymer component (A) and the thermosetting component (B). When the content of the coupling agent (E) is not less than the lower limit, the effects of using the coupling agent (E) such as improvement of dispersibility of the filler (D) in the resin and improvement of adhesion between the thermosetting protective film-forming film and the adherend can be more remarkably obtained. Further, by setting the content of the coupling agent (E) to the upper limit value or less, the occurrence of degassing can be further suppressed.
[ crosslinking agent (F) ]
When a compound having a functional group such as a vinyl group, (meth) acryloyl group, amino group, hydroxyl group, carboxyl group, or isocyanate group, which can be bonded to another compound, such as the acrylic resin, is used as the polymer component (a), the composition (III-1) and the film for forming a thermosetting protective film may contain the crosslinking agent (F). The crosslinking agent (F) is a component for bonding and crosslinking the functional group in the polymer component (a) with another compound, and the initial adhesive force and cohesive force of the film for forming a thermosetting protective film can be adjusted by crosslinking in this manner.
Examples of the crosslinking agent (F) include an organic polyisocyanate compound, an organic polyimine compound, a metal chelate crosslinking agent (a crosslinking agent having a metal chelate structure), an aziridine crosslinking agent (a crosslinking agent having an aziridine group), and the like.
Examples of the organic polyisocyanate compound include an aromatic polyisocyanate compound, an aliphatic polyisocyanate compound, and an alicyclic polyisocyanate compound (hereinafter, these compounds may be collectively abbreviated as "aromatic polyisocyanate compound and the like"); trimers, isocyanurate bodies and adducts of the aromatic polyisocyanate compounds and the like; and isocyanate-terminated urethane prepolymers obtained by reacting the aromatic polyisocyanate compound and the like with a polyol compound. The "adduct" refers to a reaction product of the aromatic polyisocyanate compound, aliphatic polyisocyanate compound or alicyclic polyisocyanate compound with a low-molecular active hydrogen-containing compound such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane or castor oil. Examples of the adduct include a xylylene diisocyanate adduct of trimethylolpropane described later. The "isocyanate-terminated urethane prepolymer" refers to a prepolymer having a urethane bond and an isocyanate group at the terminal of the molecule.
More specific examples of the organic polyisocyanate compound include 2, 4-tolylene diisocyanate; 2, 6-toluene diisocyanate; 1, 3-xylylene diisocyanate; 1, 4-xylene diisocyanate; diphenylmethane-4, 4' -diisocyanate; diphenylmethane-2, 4' -diisocyanate; 3-methyl diphenylmethane diisocyanate; hexamethylene diisocyanate; isophorone diisocyanate; dicyclohexylmethane-4, 4' -diisocyanate; dicyclohexylmethane-2, 4' -diisocyanate; a compound obtained by adding one or more of toluene diisocyanate, hexamethylene diisocyanate and xylylene diisocyanate to all or a part of the hydroxyl groups of a polyhydric alcohol such as trimethylolpropane; lysine diisocyanate, and the like.
Examples of the organic polyimine compound include N, N ' -diphenylmethane-4, 4 ' -bis (1-aziridinecarboxamide), trimethylolpropane-tri- β -aziridinylpropionate, tetramethylolmethane-tri- β -aziridinylpropionate, and N, N ' -toluene-2, 4-bis (1-aziridinecarboxamide) triethylenemelamine.
When an organic polyisocyanate compound is used as the crosslinking agent (F), a hydroxyl group-containing polymer is preferably used as the polymer component (A). When the crosslinking agent (F) has an isocyanate group and the polymer component (a) has a hydroxyl group, the crosslinked structure can be easily introduced into the film for forming a thermosetting protective film by the reaction of the crosslinking agent (F) with the polymer component (a).
The crosslinking agent (F) contained in the composition (III-1) and the film for forming a thermosetting protective film may be one kind or two or more kinds, and when two or more kinds are contained, the combination and ratio thereof may be arbitrarily selected.
When the crosslinking agent (F) is used, the content of the crosslinking agent (F) in the composition (III-1) is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and particularly preferably 0.5 to 5 parts by mass, relative to 100 parts by mass of the polymer component (A). By setting the content of the crosslinking agent (F) to the lower limit or more, the effect of using the crosslinking agent (F) can be more remarkably obtained. Further, by making the content of the crosslinking agent (F) the upper limit value or less, the excessive use of the crosslinking agent (F) is suppressed.
[ energy ray-curable resin (G) ]
The composition (III-1) and the film for forming a thermosetting protective film may contain an energy ray-curable resin (G). When the thermosetting protective film-forming film contains the energy ray-curable resin (G), the properties can be changed by irradiation with an energy ray.
The energy ray-curable resin (G) is a component obtained by polymerizing (curing) an energy ray-curable compound.
Examples of the energy ray-curable compound include compounds having at least one polymerizable double bond in the molecule, and acrylate compounds having a (meth) acryloyl group are preferable.
Examples of the acrylic ester-based compound include (meth) acrylates having a chain-like aliphatic skeleton such as trimethylolpropane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1, 4-butanediol di (meth) acrylate, and 1, 6-hexanediol di (meth) acrylate; a (meth) acrylate having a cyclic aliphatic skeleton such as dicyclopentanyl di (meth) acrylate; polyalkylene glycol (meth) acrylates such as polyethylene glycol di (meth) acrylate; an oligoester (meth) acrylate; a urethane (meth) acrylate oligomer; epoxy-modified (meth) acrylates; a polyether (meth) acrylate other than the polyalkylene glycol (meth) acrylate; itaconic acid oligomers, and the like.
The weight average molecular weight of the energy ray-curable compound is preferably 100 to 30000, more preferably 300 to 10000.
The energy ray-curable compound used for polymerization may be one kind only, or two or more kinds, and in the case of two or more kinds, a combination and a ratio thereof may be arbitrarily selected.
The energy ray-curable resin (G) contained in the composition (III-1) and the film for forming a thermosetting protective film may be one kind or two or more kinds, and when two or more kinds are contained, the combination and ratio thereof may be arbitrarily selected.
When the energy ray-curable resin (G) is used, the content of the energy ray-curable resin (G) in the composition (III-1) is preferably 1 to 95% by mass, more preferably 5 to 90% by mass, and particularly preferably 10 to 85% by mass, based on the total mass of the composition (III-1).
[ photopolymerization initiator (H) ]
When the composition (III-1) and the film for forming a thermosetting protective film contain the energy ray-curable resin (G), a photopolymerization initiator (H) may be contained in order to efficiently carry out the polymerization reaction of the energy ray-curable resin (G).
Examples of the photopolymerization initiator (H) in the composition (III-1) include benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, and benzoin dimethyl ketal; acetophenone compounds such as acetophenone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, and 2, 2-dimethoxy-1, 2-diphenylethan-1-one; acylphosphine oxide compounds such as phenylbis (2,4, 6-trimethylbenzoyl) phosphine oxide and 2,4, 6-trimethylbenzoyl diphenylphosphine oxide; sulfides such as benzyl phenyl sulfide and tetramethylthiuram monosulfide; α -ketol compounds such as 1-hydroxycyclohexyl phenyl ketone; azo compounds such as azobisisobutyronitrile; titanocene compounds such as titanocene; thioxanthone compounds such as thioxanthone; a peroxide compound; diketone compounds such as diacetyl; benzil; dibenzoyl; benzophenone; 2, 4-diethylthioxanthone; 1, 2-diphenylmethane; 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl ] propanone; 2-chloroanthraquinone, and the like.
Further, examples of the photopolymerization initiator include quinone compounds such as 1-chloroanthraquinone; photosensitizers such as amines, and the like.
The composition (III-1) and the film for forming a thermosetting protective film may contain only one kind of photopolymerization initiator (H), or two or more kinds thereof, and when two or more kinds thereof are contained, the combination and ratio thereof may be arbitrarily selected.
When the photopolymerization initiator (H) is used, the content of the photopolymerization initiator (H) in the composition (III-1) is preferably 0.1 to 20 parts by mass, more preferably 1 to 10 parts by mass, and particularly preferably 2 to 5 parts by mass, relative to 100 parts by mass of the content of the energy ray-curable resin (G).
[ colorant (I) ]
The composition (III-1) and the film for forming a thermosetting protective film may contain a colorant (I).
Examples of the colorant (I) include known colorants such as inorganic pigments, organic pigments, and organic dyes.
Examples of the organic pigments and organic dyes include aminium (aminium) pigments, cyanine pigments, merocyanine pigments, croconium (croconium) pigments, squarylium (squarylium) pigments, azulenium (azulenium) pigments, polymethine pigments, naphthoquinone pigments, pyrylium pigments, phthalocyanine pigments, naphthalocyanine pigments, naphthalimide (naphthaloctamide) pigments, azo pigments, condensed azo pigments, indigo pigments, perinone pigments, perylene pigments, dioxazine pigments, quinacridone pigments, isoindolinone pigments, quinophthalone pigments, pyrrole pigments, thioindigo pigments, metal complex pigments (metal complex salt pigments), dithiol metal complex pigments, indole pigments, triarylmethane pigments, anthraquinone pigments, naphthol pigments, methine pigments, and methine pigments, Benzimidazolone pigments, pyranthrone pigments, threne pigments and the like.
Examples of the inorganic pigments include carbon black, cobalt pigments, iron pigments, chromium pigments, titanium pigments, vanadium pigments, zirconium pigments, molybdenum pigments, ruthenium pigments, platinum pigments, ITO (indium tin oxide) pigments, ATO (antimony tin oxide) pigments, and the like.
The composition (III-1) and the film for forming a thermosetting protective film may contain only one kind of the colorant (I), or two or more kinds thereof, and when two or more kinds thereof are contained, the combination and ratio thereof may be arbitrarily selected.
When the colorant (I) is used, the content of the colorant (I) in the film for forming a thermosetting protective film may be appropriately adjusted according to the purpose. For example, the content of the colorant (I) in the thermosetting protective film-forming film and the light transmittance of the protective film can be adjusted to adjust the printing visibility when laser printing is performed on the protective film. Further, by adjusting the content of the colorant (I) in the thermosetting protective film-forming film, the design of the protective film can be improved, and the polishing trace on the back surface of the semiconductor wafer can be made less noticeable. In view of these points, the ratio of the content of the colorant (I) to the total content of all the components except the solvent in the composition (III-1) (i.e., the ratio of the content of the colorant (I) in the film for forming a thermosetting protective film to the total mass of the film for forming a thermosetting protective film) is preferably 0.1 to 10 mass%, more preferably 0.1 to 7.5 mass%, and particularly preferably 0.1 to 5 mass%. By setting the ratio to the lower limit or more, the effect of using the colorant (I) can be more remarkably obtained. Further, by setting the ratio to the upper limit or less, an excessive decrease in the light transmittance of the thermosetting protective film-forming film can be suppressed.
[ general additive (J) ]
The composition (III-1) and the film for forming a thermosetting protective film may contain the general-purpose additive (J) within a range not to impair the effects of the present invention.
The general-purpose additive (J) may be a known additive, may be arbitrarily selected according to the purpose, and is not particularly limited, but preferable additives include, for example, a plasticizer, an antistatic agent, an antioxidant, and a gettering agent (gelling agent).
The composition (III-1) and the film for forming a thermosetting protective film may contain only one kind of the general-purpose additive (J), or two or more kinds thereof, and when two or more kinds thereof are contained, the combination and ratio thereof may be arbitrarily selected.
The content of the general-purpose additive (J) in the composition (III-1) and the film for forming a thermosetting protective film is not particularly limited, and may be appropriately selected depending on the purpose.
[ solvent ]
The composition (III-1) preferably further contains a solvent. The composition (III-1) containing a solvent was excellent in handling properties.
The solvent is not particularly limited, but preferable examples thereof include hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, 2-propanol, isobutanol (2-methylpropane-1-ol), and 1-butanol; esters such as ethyl acetate; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran; amides (compounds having an amide bond) such as dimethylformamide and N-methylpyrrolidone.
The solvent contained in the composition (III-1) may be one kind or two or more kinds, and in the case of two or more kinds, the combination and ratio thereof may be arbitrarily selected.
The solvent contained in the composition (III-1) is preferably methyl ethyl ketone or the like, since the components contained in the composition (III-1) can be mixed more uniformly.
The content of the solvent in the composition (III-1) is not particularly limited, and may be appropriately selected depending on the kind of the component other than the solvent, for example.
Preparation method of composition for Forming thermosetting protective film
The composition for forming a thermosetting protective film such as the composition (III-1) can be obtained by blending the respective components constituting the composition.
For example, the composition for forming a thermosetting protective film can be prepared by the same method as the adhesive composition described above, except that the kind of the blending component is different.
Film for forming energy ray-curable protective film
As long as the protective film has a degree of curing to a degree that the protective film sufficiently exhibits its function, the curing conditions for forming the protective film by attaching the energy ray-curable protective film forming film to the back surface of the semiconductor wafer and curing the film with an energy ray are not particularly limited, and may be appropriately selected depending on the kind of the energy ray-curable protective film forming film.
For example, the illuminance of the energy ray when the energy ray-curable protective film-forming film is cured by an energy ray is preferably 120 to 280mW/cm2. The quantity of the energy ray during the curing is preferably 100 to 1000mJ/cm2。
The energy ray-curable protective film-forming film includes an energy ray-curable protective film-forming film containing an energy ray-curable component (a), and preferably an energy ray-curable protective film-forming film containing an energy ray-curable component (a) and a filler.
In the film for forming an energy ray-curable protective film, the energy ray-curable component (a) is preferably uncured, preferably adhesive, and more preferably uncured and adhesive.
< composition for Forming energy ray-curable protective film (IV-1) >
Examples of a preferable energy ray-curable composition for forming a protective film include an energy ray-curable composition for forming a protective film (IV-1) (in the present specification, it may be abbreviated as "composition (IV-1)") containing the energy ray-curable component (a).
[ energy ray-curable component (a) ]
The energy ray-curable component (a) is a component which is cured by irradiation with an energy ray, and is a component for imparting film formability, flexibility, and the like to the energy ray-curable protective film-forming film, and for forming a hard resin film after curing.
Examples of the energy ray-curable component (a) include a polymer (a1) having an energy ray-curable group and a weight-average molecular weight of 80000 to 2000000, and a compound (a2) having an energy ray-curable group and a molecular weight of 100 to 80000. At least a portion of the polymer (a1) may or may not be crosslinked by a crosslinking agent.
(a polymer (a1) having an energy ray-curable group and a weight-average molecular weight of 80000 to 2000000.)
Examples of the polymer (a1) having an energy ray-curable group and a weight-average molecular weight of 80000 to 2000000 include an acrylic resin (a1-1) obtained by reacting an acrylic polymer (a11) having a functional group reactive with a group of another compound with an energy ray-curable compound (a12), and the energy ray-curable compound (a12) having an energy ray-curable group such as a group reactive with the functional group and an energy ray-curable double bond.
Examples of the functional group that can react with a group of another compound include a hydroxyl group, a carboxyl group, an amino group, a substituted amino group (a group in which one or two hydrogen atoms of the amino group are substituted with a group other than a hydrogen atom), an epoxy group, and the like. Among them, the functional group is preferably a group other than a carboxyl group from the viewpoint of preventing circuit corrosion of a semiconductor wafer, a semiconductor chip, or the like.
Among them, the functional group is preferably a hydroxyl group.
Acrylic Polymer having functional group (a11)
Examples of the acrylic polymer (a11) having the functional group include polymers obtained by copolymerizing an acrylic monomer having the functional group and an acrylic monomer having no functional group, and polymers obtained by copolymerizing monomers other than the acrylic monomer (non-acrylic monomer) in addition to these monomers.
The acrylic polymer (a11) may be a random copolymer or a block copolymer, and a known polymerization method may be used.
Examples of the acrylic monomer having the functional group include a hydroxyl group-containing monomer, a carboxyl group-containing monomer, an amino group-containing monomer, a substituted amino group-containing monomer, and an epoxy group-containing monomer.
Examples of the hydroxyl group-containing monomer include hydroxyalkyl (meth) acrylates such as hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate; and non (meth) acrylic unsaturated alcohols (unsaturated alcohols having no (meth) acryloyl skeleton) such as vinyl alcohol and allyl alcohol.
Examples of the carboxyl group-containing monomer include ethylenically unsaturated monocarboxylic acids (monocarboxylic acids having an ethylenically unsaturated bond) such as (meth) acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids (dicarboxylic acids having an ethylenically unsaturated bond) such as fumaric acid, itaconic acid, maleic acid, and citraconic acid; anhydrides of said ethylenically unsaturated dicarboxylic acids; and carboxyalkyl (meth) acrylates such as 2-carboxyethyl methacrylate.
The acrylic monomer having the functional group is preferably a hydroxyl group-containing monomer.
The acrylic monomer having the functional group constituting the acrylic polymer (a11) may be one type only, or two or more types, and when two or more types are used, the combination and ratio thereof may be arbitrarily selected.
Examples of the acrylic monomer having no functional group include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-octyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, dodecyl (meth) acrylate, n-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, and the like, And alkyl (meth) acrylates having a chain structure in which the alkyl group constituting the alkyl ester is 1 to 18 carbon atoms, such as tetradecyl (meth) acrylate (myristyl (meth) acrylate), pentadecyl (meth) acrylate, hexadecyl (meth) acrylate (palmityl (meth) acrylate), heptadecyl (meth) acrylate, and octadecyl (meth) acrylate (stearyl (meth) acrylate).
Examples of the acrylic monomer having no functional group include (meth) acrylates containing an alkoxyalkyl group such as methoxymethyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxymethyl (meth) acrylate, and ethoxyethyl (meth) acrylate; aromatic group-containing (meth) acrylates such as aryl (meth) acrylates including phenyl (meth) acrylate; non-crosslinkable (meth) acrylamide and derivatives thereof; and non-crosslinkable (meth) acrylic esters having a tertiary amino group such as N, N-dimethylaminoethyl (meth) acrylate and N, N-dimethylaminopropyl (meth) acrylate.
The acrylic monomer having no functional group constituting the acrylic polymer (a11) may be one type only, or two or more types, and when two or more types are used, the combination and ratio thereof may be arbitrarily selected.
Examples of the non-acrylic monomer include olefins such as ethylene and norbornene; vinyl acetate; styrene, and the like.
The non-acrylic monomer constituting the acrylic polymer (a11) may be one kind only, or two or more kinds, and when two or more kinds are used, the combination and ratio thereof may be arbitrarily selected.
In the acrylic polymer (a11), the ratio (content) of the amount of the structural unit derived from the acrylic monomer having the functional group to the total amount of the structural units constituting the acrylic polymer (a11) is preferably 0.1 to 50% by mass, more preferably 1 to 40% by mass, and particularly preferably 3 to 30% by mass. By making the ratio within the above range, the content of the energy ray-curable group in the acrylic resin (a1-1) obtained by copolymerization of the acrylic polymer (a11) and the energy ray-curable compound (a12) can be easily adjusted to a preferable range of the degree of curing of the protective film.
The acrylic polymer (a11) constituting the acrylic resin (a1-1) may be one type or two or more types, and when two or more types are used, the combination and ratio thereof may be arbitrarily selected.
In the composition (IV-1), the proportion of the content of the acrylic resin (a1-1) to the total content of components other than the solvent (i.e., the proportion of the content of the acrylic resin (a1-1) in the energy ray-curable protective film-forming film to the total mass of the film) is preferably 1 to 70 mass%, more preferably 5 to 60 mass%, and particularly preferably 10 to 50 mass%.
Energy ray-curable compound (a12)
The energy ray-curable compound (a12) preferably has one or more selected from the group consisting of an isocyanate group, an epoxy group, and a carboxyl group as a group capable of reacting with a functional group of the acrylic polymer (a11), and more preferably the energy ray-curable compound (a12) has an isocyanate group as the group. For example, when the energy ray-curable compound (a12) has an isocyanate group as the group, the isocyanate group easily reacts with a hydroxyl group of the acrylic polymer (a11) having the hydroxyl group as the functional group.
The number of the energy ray-curable groups contained in one molecule of the energy ray-curable compound (a12) is not particularly limited, and may be appropriately selected in consideration of physical properties such as shrinkage ratio required for the intended protective film.
For example, the energy ray-curable compound (a12) preferably has 1 to 5 energy ray-curable groups in one molecule, and more preferably 1 to 3 energy ray-curable groups.
Examples of the energy ray-curable compound (a12) include 2-methacryloyloxyethyl isocyanate, m-isopropenyl- α, α -dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, and 1,1- (bisacryloxymethyl) ethyl isocyanate;
an acryloyl monoisocyanate compound obtained by the reaction of a diisocyanate compound or a polyisocyanate compound with hydroxyethyl (meth) acrylate;
and an acryloyl monoisocyanate compound obtained by reacting a diisocyanate compound or a polyisocyanate compound with a polyol compound and hydroxyethyl (meth) acrylate.
Among them, the energy ray-curable compound (a12) is preferably 2-methacryloyloxyethyl isocyanate.
The energy ray-curable compound (a12) constituting the acrylic resin (a1-1) may be one kind or two or more kinds, and when two or more kinds are used, the combination and ratio thereof may be arbitrarily selected.
In the acrylic resin (a1-1), the ratio of the content of the energy ray-curable group derived from the energy ray-curable compound (a12) to the content of the functional group derived from the acrylic polymer (a11) is preferably 20 to 120 mol%, more preferably 35 to 100 mol%, and particularly preferably 50 to 100 mol%. By making the ratio of the content within the above range, the adhesive force of the protective film becomes larger. In addition, when the energy ray-curable compound (a12) is a monofunctional compound (having one group in one molecule), the upper limit of the proportion of the content is 100 mol%, and when the energy ray-curable compound (a12) is a polyfunctional compound (having two or more groups in one molecule), the upper limit of the proportion of the content may be more than 100 mol%.
The weight average molecular weight (Mw) of the polymer (a1) is preferably 100000 to 2000000, more preferably 300000 to 1500000.
Wherein "weight average molecular weight" is the same as previously described.
When at least a part of the polymer (a1) is crosslinked by a crosslinking agent, the polymer (a1) may be a polymer which is polymerized by a monomer having a group which reacts with a crosslinking agent and is not one of the monomers described above as monomers constituting the acrylic polymer (a11) and which is crosslinked at a group which reacts with the crosslinking agent, or may be a polymer which is crosslinked at a group which reacts with the functional group from the energy ray-curable compound (a 12).
The polymer (a1) contained in the composition (IV-1) and the energy ray-curable protective film-forming film may be one type or two or more types, and when two or more types are used, the combination and ratio thereof may be arbitrarily selected.
(Compound (a2) having an energy ray-curable group and a molecular weight of 100 to 80000.)
Examples of the energy ray-curable group in the compound (a2) having an energy ray-curable group and a molecular weight of 100 to 80000 include groups containing an energy ray-curable double bond, and preferable examples thereof include a (meth) acryloyl group, a vinyl group and the like.
The compound (a2) is not particularly limited as long as the above conditions are satisfied, and examples thereof include a low molecular weight compound having an energy ray-curable group, an epoxy resin having an energy ray-curable group, and a phenol resin having an energy ray-curable group.
Examples of the low molecular weight compound having an energy ray-curable group in the compound (a2) include polyfunctional monomers and oligomers, and an acrylate compound having a (meth) acryloyl group is preferable.
Examples of the acrylate-based compound include 2-hydroxy-3- (meth) acryloyloxypropyl methacrylate, polyethylene glycol di (meth) acrylate, propoxylated ethoxylated bisphenol A di (meth) acrylate, 2-bis [4- ((meth) acryloyloxypolyethoxy) phenyl ] propane, ethoxylated bisphenol A di (meth) acrylate, 2-bis [4- ((meth) acryloyloxydiethoxy) phenyl ] propane, 9-bis [4- (2- (meth) acryloyloxyethoxy) phenyl ] fluorene, 2-bis [4- ((meth) acryloyloxypropyloxy) phenyl ] propane, tricyclodecanedimethanol di (meth) acrylate, 1, 10-decanediol di (meth) acrylate, and mixtures thereof, Bifunctional (meth) acrylates such as 1, 6-hexanediol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene ether glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, 2-bis [4- ((meth) acryloyloxyethoxy) phenyl ] propane, neopentyl glycol di (meth) acrylate, ethoxylated polypropylene glycol di (meth) acrylate, and 2-hydroxy-1, 3-di (meth) acryloyloxypropane;
polyfunctional (meth) acrylates such as tris (2- (meth) acryloyloxyethyl) isocyanurate, epsilon-caprolactone-modified tris- (2- (meth) acryloyloxyethyl) isocyanurate, ethoxylated glycerol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, dipentaerythritol poly (meth) acrylate, and dipentaerythritol hexa (meth) acrylate;
and polyfunctional (meth) acrylate oligomers such as urethane (meth) acrylate oligomers.
As the epoxy resin having an energy ray-curable group and the phenol resin having an energy ray-curable group in the compound (a2), for example, the resins described in japanese patent application laid-open No. 2013-194102 "paragraph 0043 and the like can be used. Such a resin is also a resin constituting a thermosetting component described later, but in the present invention, it is regarded as the compound (a 2).
The weight average molecular weight of the compound (a2) is preferably 100 to 30000, more preferably 300 to 10000.
The compound (a2) contained in the composition (IV-1) and the energy ray-curable protective film-forming film may be one type or two or more types, and when two or more types are used, the combination and ratio thereof may be arbitrarily selected.
[ Polymer (b) having no energy ray-curable group ]
When the composition (IV-1) and the film for forming an energy ray-curable protective film contain the compound (a2) as the energy ray-curable component (a), it is preferable that the composition further contains a polymer (b) having no energy ray-curable group.
At least a portion of the polymer (b) may or may not be crosslinked by a crosslinking agent.
Examples of the polymer (b) having no energy ray-curable group include acrylic polymers, phenoxy resins, urethane resins, polyesters, rubber resins, and acrylic urethane resins.
Among them, the polymer (b) is preferably an acrylic polymer (hereinafter, may be abbreviated as "acrylic polymer (b-1)").
The acrylic polymer (b-1) may be a known acrylic polymer, and may be, for example, a homopolymer of one acrylic monomer, a copolymer of two or more acrylic monomers, or a copolymer of one or more acrylic monomers and one or more monomers (non-acrylic monomers) other than the acrylic monomers.
Examples of the acrylic monomer constituting the acrylic polymer (b-1) include alkyl (meth) acrylates, (meth) acrylates having a cyclic skeleton, glycidyl group-containing (meth) acrylates, hydroxyl group-containing (meth) acrylates, and substituted amino group-containing (meth) acrylates. Here, the "substituted amino group" is the same as previously described.
Examples of the alkyl (meth) acrylate include the same alkyl (meth) acrylates as those of the acrylic monomers having no functional group (alkyl (meth) acrylates having a chain structure in which the alkyl group constituting the alkyl ester has 1 to 18 carbon atoms, and the like) constituting the acrylic polymer (a11) described above.
Examples of the (meth) acrylate having a cyclic skeleton include cycloalkyl (meth) acrylates such as isobornyl (meth) acrylate and dicyclopentanyl (meth) acrylate;
aralkyl (meth) acrylates such as benzyl (meth) acrylate;
cycloalkenyl (meth) acrylates such as dicyclopentenyl (meth) acrylate;
cycloalkenyloxyalkyl (meth) acrylates such as dicyclopentenyloxyethyl (meth) acrylate, and the like.
Examples of the glycidyl group-containing (meth) acrylate include glycidyl (meth) acrylate and the like.
Examples of the hydroxyl group-containing (meth) acrylate include hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate.
Examples of the substituted amino group-containing (meth) acrylate include N-methylaminoethyl (meth) acrylate and the like.
Examples of the non-acrylic monomer constituting the acrylic polymer (b-1) include olefins such as ethylene and norbornene; vinyl acetate; styrene, and the like.
Examples of the polymer (b) having no energy ray-curable group, at least a part of which is crosslinked by a crosslinking agent, include polymers obtained by reacting a reactive functional group in the polymer (b) with a crosslinking agent.
The reactive functional group is not particularly limited as long as it is appropriately selected according to the kind of the crosslinking agent and the like. For example, when the crosslinking agent is a polyisocyanate compound, the reactive functional group includes a hydroxyl group, a carboxyl group, an amino group, and the like, and among them, a hydroxyl group having high reactivity with an isocyanate group is preferable. When the crosslinking agent is an epoxy compound, examples of the reactive functional group include a carboxyl group, an amino group, and an amide group, and among them, a carboxyl group having high reactivity with an epoxy group is preferable. However, from the viewpoint of preventing the circuit of the semiconductor wafer or the semiconductor chip from corroding, it is preferable that the reactive functional group is a group other than a carboxyl group.
Examples of the polymer (b) having the reactive functional group and not having an energy ray-curable group include polymers obtained by polymerizing a monomer having at least the reactive functional group. When the polymer (b) is the acrylic polymer (b-1), the monomer having the reactive functional group may be used as either one or both of the acrylic monomer and the non-acrylic monomer exemplified as the monomer constituting the acrylic polymer (b-1). Examples of the polymer (b) having a hydroxyl group as a reactive functional group include polymers obtained by polymerizing a hydroxyl group-containing (meth) acrylate, and polymers obtained by polymerizing the above-mentioned monomers in which one or two or more hydrogen atoms of the acrylic monomer or the non-acrylic monomer are substituted with the reactive functional group.
In the polymer (b) having a reactive functional group, the proportion (content) of the amount of the structural unit derived from the monomer having a reactive functional group to the total amount of the structural units constituting the polymer (b) is preferably 1 to 20% by mass, and more preferably 2 to 10% by mass. By making the ratio within the above range, the degree of crosslinking in the polymer (b) becomes a more preferable range.
The weight average molecular weight (Mw) of the polymer (b) having no energy ray-curable group is preferably 10000 to 2000000, more preferably 100000 to 1500000, from the viewpoint of improving the film-forming property of the composition (IV-1). Wherein "weight average molecular weight" is the same as previously described.
The composition (IV-1) and the energy ray-curable protective film-forming film may contain only one kind of polymer (b) having no energy ray-curable group, or two or more kinds thereof, and when two or more kinds thereof are contained, the combination and ratio thereof may be arbitrarily selected.
The composition (IV-1) may be a composition containing either one or both of the polymer (a1) and the compound (a 2). When the composition (IV-1) contains the compound (a2), it preferably further contains a polymer (b) having no energy ray-curable group, and in this case, it preferably further contains the compound (a 1). Further, the composition (IV-1) may contain not the compound (a2) but the polymer (a1) and the polymer (b) having no energy ray-curable group at the same time.
When the composition (IV-1) contains the polymer (a1), the compound (a2), and the polymer (b) having no energy ray-curable group, the content of the compound (a2) in the composition (IV-1) is preferably 10 to 400 parts by mass, more preferably 30 to 350 parts by mass, relative to 100 parts by mass of the total content of the polymer (a1) and the polymer (b) having no energy ray-curable group.
In the composition (IV-1), the ratio of the total content of the energy ray-curable component (a) and the polymer (b) having no energy ray-curable group to the total content of components other than the solvent (i.e., the ratio of the total content of the energy ray-curable component (a) and the polymer (b) having no energy ray-curable group to the total mass of the film in the energy ray-curable protective film forming film) is preferably 5 to 90% by mass, more preferably 10 to 80% by mass, and particularly preferably 20 to 70% by mass. When the ratio of the content of the energy ray-curable component is within the above range, the energy ray-curability of the energy ray-curable protective film-forming film becomes better.
The composition (IV-1) may contain one or more selected from the group consisting of a thermosetting component, a filler, a coupling agent, a crosslinking agent, a photopolymerization initiator, a colorant, and a general-purpose additive, depending on the purpose, in addition to the energy ray-curable component.
The thermosetting component, the filler, the coupling agent, the crosslinking agent, the photopolymerization initiator, the colorant and the general-purpose additive in the composition (IV-1) may be the same components as those of the thermosetting component (B), the filler (D), the coupling agent (E), the crosslinking agent (F), the photopolymerization initiator (H), the colorant (I) and the general-purpose additive (J) in the composition (III-1), respectively.
For example, by using the composition (IV-1) containing the energy ray-curable component and the thermosetting component, the adhesive force of the formed film for forming an energy ray-curable protective film to an adherend is increased by heating, and the strength of the resin film formed from the film for forming an energy ray-curable protective film is also increased.
By using the composition (IV-1) containing the energy ray-curable component and the colorant, the formed energy ray-curable protective film-forming film exhibits the same effects as those of the case where the thermosetting protective film-forming film described above contains the colorant (I).
In the composition (IV-1), the thermosetting component, the filler, the coupling agent, the crosslinking agent, the photopolymerization initiator, the colorant and the general-purpose additive may be used singly or in combination of two or more, and when two or more are used simultaneously, the combination and ratio thereof may be arbitrarily selected.
The content of the thermosetting component, the filler, the coupling agent, the crosslinking agent, the photopolymerization initiator, the colorant and the general-purpose additive in the composition (IV-1) is not particularly limited as long as it is appropriately adjusted according to the purpose.
Since the handling properties of the composition (IV-1) are improved by dilution, it is preferable to further contain a solvent.
Examples of the solvent contained in the composition (IV-1) include the same solvents as those in the composition (III-1).
The composition (IV-1) may contain only one solvent, or may contain two or more solvents.
The content of the solvent in the composition (IV-1) is not particularly limited, and may be appropriately selected depending on the kind of the component other than the solvent, for example.
Method for producing composition for forming energy ray-curable protective film
The energy ray-curable composition for forming a protective film such as the composition (IV-1) can be obtained by blending the respective components constituting the composition.
The energy ray-curable composition for forming a protective film can be prepared, for example, by the same method as the adhesive composition described above, except that the kinds of the blending components are different.
Very good peeling film
The release film is an arbitrary component that can be provided as the outermost layer on the protective film-forming film side of the protective film-forming composite sheet. In the composite sheet for forming a protective film in a state where a release film is provided on a film for forming a protective film, when the release film is removed from the film for forming a protective film, peeling electrification of the composite sheet for forming a protective film is suppressed.
The release film may be a known release film, and examples thereof include a release film obtained by subjecting one surface of a resin film such as a polyethylene terephthalate film to a release treatment such as a silicone treatment.
The release film may have the same configuration as the release improving layer as the intermediate layer.
The thickness of the release film is not particularly limited, and may be, for example, 10 to 1000 μm.
As an embodiment of the composite sheet for forming a protective film, for example, there is mentioned a composite sheet for forming a protective film comprising a support sheet and a film for forming a protective film formed on one surface of the support sheet, wherein the support sheet comprises a base material and an antistatic layer formed on one surface or both surfaces of the base material, the total light transmittance of the support sheet is 85% or more, and the surface resistivity of the composite sheet for forming a protective film is 1.0 × 1011Omega/□ or less, said antistatic propertyThe layer contains one or more kinds selected from the group consisting of a pyrimidinium salt, a pyridinium salt, a piperidinium salt, a pyrrolidinium salt, an imidazolium salt, a morpholinium salt, a sulfonium salt, a phosphonium salt, an ammonium salt, poly (3, 4-ethylenedioxythiophene)/polystyrene sulfonic acid, and a carbon nanotube.
As an embodiment of the composite sheet for forming a protective film, for example, there is mentioned a composite sheet for forming a protective film comprising a support sheet and a film for forming a protective film formed on one surface of the support sheet, wherein the support sheet comprises a base material and an antistatic layer formed on one surface or both surfaces of the base material, the total light transmittance of the support sheet is 85% or more, and the surface resistivity of the composite sheet for forming a protective film is 1.0 × 1011Omega/□ or less, wherein the antistatic layer contains one or more selected from the group consisting of a pyrimidinium salt, a pyridinium salt, a piperidinium salt, a pyrrolidinium salt, an imidazolium salt, a morpholinium salt, a sulfonium salt, a phosphonium salt, an ammonium salt, poly (3, 4-ethylenedioxythiophene)/polystyrene sulfonic acid, and carbon nanotubes, and the total thickness of the antistatic layers formed on one or both surfaces of the substrate is 10 to 200 nm.
One embodiment of the composite sheet for forming a protective film includes, for example, a composite sheet for forming a protective film comprising a support sheet and a film for forming a protective film formed on one surface of the support sheet, wherein the support sheet comprises a base material and an antistatic layer formed on one surface or both surfaces of the base material, and the composite sheet for forming a protective film has a surface resistivity of 1.0 × 1011Omega/□ or less, and the support sheet has a haze of 43% or less, and the antistatic layer contains one or more selected from the group consisting of a pyrimidinium salt, a pyridinium salt, a piperidinium salt, a pyrrolidinium salt, an imidazolium salt, a morpholinium salt, a sulfonium salt, a phosphonium salt, an ammonium salt, poly (3, 4-ethylenedioxythiophene)/polystyrene sulfonic acid, and a carbon nanotube.
One embodiment of the composite sheet for forming a protective film includes, for example, a composite sheet for forming a protective film comprising a support sheet and a film for forming a protective film formed on one surface of the support sheet, wherein the composite sheet for forming a protective film comprisesThe support sheet comprises a base material and an antistatic layer formed on one or both surfaces of the base material, and the surface resistivity of the composite sheet for forming the protective film is 1.0 x 1011Omega/□ or less, the support sheet has a haze of 43% or less, the antistatic layer contains one or more selected from the group consisting of a pyrimidinium salt, a pyridinium salt, a piperidinium salt, a pyrrolidinium salt, an imidazolium salt, a morpholinium salt, a sulfonium salt, a phosphonium salt, an ammonium salt, poly (3, 4-ethylenedioxythiophene)/polystyrene sulfonic acid, and carbon nanotubes, and the total thickness of the antistatic layers formed on one or both surfaces of the substrate is 10 to 200 nm.
As an embodiment of the composite sheet for forming a protective film, for example, there is mentioned a composite sheet for forming a protective film comprising a support sheet and a film for forming a protective film formed on one surface of the support sheet, wherein the support sheet comprises a base material and an antistatic layer formed on one surface or both surfaces of the base material, the total light transmittance of the support sheet is 85% or more, and the surface resistivity of the composite sheet for forming a protective film is 1.0 × 1011Omega/□ or less, and the support sheet has a haze of 43% or less, and the antistatic layer contains one or more selected from the group consisting of a pyrimidinium salt, a pyridinium salt, a piperidinium salt, a pyrrolidinium salt, an imidazolium salt, a morpholinium salt, a sulfonium salt, a phosphonium salt, an ammonium salt, poly (3, 4-ethylenedioxythiophene)/polystyrene sulfonic acid, and a carbon nanotube.
As an embodiment of the composite sheet for forming a protective film, for example, there is mentioned a composite sheet for forming a protective film comprising a support sheet and a film for forming a protective film formed on one surface of the support sheet, wherein the support sheet comprises a base material and an antistatic layer formed on one surface or both surfaces of the base material, the total light transmittance of the support sheet is 85% or more, and the surface resistivity of the composite sheet for forming a protective film is 1.0 × 1011Omega/□ or less, the support sheet has a haze of 43% or less, and the antistatic layer contains a compound selected from the group consisting of a pyrimidinium salt, a pyridinium salt, a piperidinium salt, a pyrrolidinium salt, an imidazolium salt, a morpholinium salt, a sulfonium salt, a phosphonium salt, an ammonium salt, and poly (3, 4-ethylenedioxythiophene)/polystyreneAnd one or more selected from the group consisting of alkene sulfonic acid and carbon nanotube, wherein the total thickness of the antistatic layers formed on one or both surfaces of the substrate is 10-200 nm.
Manufacturing method of composite sheet for protective film formation
The composite sheet for forming a protective film can be produced by laminating the respective layers so that the respective layers are in a corresponding positional relationship. The formation method of each layer is the same as that described previously.
For example, when an adhesive layer is laminated on a substrate in the production of a support sheet, the adhesive composition described above may be applied to the substrate and dried as necessary. This method is also applicable to any of the case where an adhesive layer is laminated on the uneven surface of the base material and the case where an adhesive layer is laminated on the smooth surface of the base material. This method is particularly suitable for the case where an adhesive layer is laminated on the uneven surface. This is because, when this method is applied, a high effect of suppressing generation of a void portion between the uneven surface of the base material and the adhesive layer can be obtained.
The same applies to the case where a back surface antistatic layer or a front surface antistatic layer is laminated on a base material when a support sheet is manufactured.
In this case, a back surface antistatic layer or a front surface antistatic layer can be laminated on the substrate by the same method as the method for laminating the adhesive layer described above, except that the antistatic composition (VI-1) is used instead of the adhesive composition.
On the other hand, when an adhesive layer is laminated on a substrate, the following method may be applied instead of the method of coating an adhesive composition on a substrate as described above.
That is, the adhesive layer can be laminated on the substrate by a method in which the adhesive composition is applied to the release film and dried as necessary to form the adhesive layer on the release film and the exposed surface of the adhesive layer is bonded to the surface of the substrate. This method is particularly suitable for the case where an adhesive layer is laminated on the smooth surface. The reason for this is that when this method is applied, a high effect of suppressing the generation of voids can be obtained between the smooth surface of the base material and the adhesive layer.
The same applies to the case where a back surface antistatic layer or a front surface antistatic layer is laminated on a base material using a release film when a support sheet is manufactured.
In this case, a back surface antistatic layer or a front surface antistatic layer can be laminated on the substrate by the same method as the method for laminating the adhesive layer using the release film described above, except that the antistatic composition (VI-1) is used instead of the adhesive composition.
Although the case where an adhesive layer, a back surface antistatic layer, or a front surface antistatic layer is laminated on a substrate has been described above, the above method can be applied to a case where another layer is laminated, for example, a case where an intermediate layer is laminated on a substrate.
On the other hand, for example, when a film for forming a protective film is further laminated on an adhesive layer laminated on a base material, the film for forming a protective film can be directly formed by applying a composition for forming a protective film on the adhesive layer. A layer other than the film for forming a protective film can be laminated on the adhesive layer by the same method using the composition for forming the layer. In this manner, when a new layer (hereinafter, abbreviated as "second layer") is formed on any one layer (hereinafter, abbreviated as "first layer") already laminated on the base material to form a laminated structure of two continuous layers (in other words, a laminated structure of a first layer and a second layer), a method of coating a composition for forming the second layer on the first layer and drying it as necessary can be applied.
However, it is preferable that the second layer is formed in advance on the release film using a composition for forming the layer, and an exposed surface of the formed second layer on the opposite side to the side in contact with the release film is bonded to an exposed surface of the first layer, thereby forming a continuous two-layer laminated structure. In this case, the composition is preferably applied to the release-treated surface of the release film. After the laminated structure is formed, the release film may be removed as needed.
Here, although an example is given in which a film for forming a protective film is laminated on an adhesive layer, a target laminated structure may be arbitrarily selected, for example, a case in which an intermediate layer is laminated on an adhesive layer, a case in which a film for forming a protective film is laminated on an intermediate layer, a case in which an adhesive layer is laminated on a surface antistatic layer, or the like.
In this manner, since all layers other than the base material constituting the composite sheet for forming a protective film can be laminated by a method of forming the layers on the release film in advance and bonding the layers to the surface of the target layer, the composite sheet for forming a protective film can be produced by appropriately selecting the layers to be subjected to the above steps as needed.
The composite sheet for forming a protective film is generally stored in a state in which a release film is bonded to the surface of the outermost layer (for example, a film for forming a protective film) of the composite sheet for forming a protective film on the side opposite to the support sheet. Therefore, by applying a composition for forming the outermost layer, such as a composition for forming a protective film, to the release film (preferably, on the release-treated surface thereof) and drying it as necessary, the outermost layer is formed on the release film, and by any of the above-described methods, the remaining layers are laminated on the exposed surface of the layer on the opposite side to the side in contact with the release film, and the release film is bonded without removing the release film, whereby a composite sheet for forming a protective film with a release film can be obtained.
Manufacturing method of semiconductor chip
The protective film-forming composite sheet is useful for the production of semiconductor chips.
As a method for manufacturing a semiconductor chip in this case, for example, there is a method for manufacturing a semiconductor chip including: a step of attaching the film for forming a protective film in the composite sheet for forming a protective film to a semiconductor wafer (hereinafter, sometimes abbreviated as "attaching step"); a step of forming a protective film by curing the protective film-forming film attached to the semiconductor wafer (hereinafter, may be abbreviated as "protective film-forming step"); a step of dividing the semiconductor wafer and cutting the protective film or the film for forming the protective film to obtain a plurality of semiconductor chips each including the cut protective film or the film for forming the protective film (hereinafter, sometimes abbreviated as "dividing step"); and a step of separating the semiconductor chip provided with the cut protective film or the film for forming the protective film from the support sheet and picking up the semiconductor chip (hereinafter, sometimes abbreviated as "picking up step"), and further, a step of irradiating the film for forming the protective film or the protective film with laser light and printing the semiconductor chip (hereinafter, sometimes abbreviated as "laser printing step") is provided between the attaching step and the picking up step.
In the manufacturing method, the protective film forming step, the laser printing step, the dividing step, and the picking step are performed after the attaching step. In addition, the order of performing the protective film forming step, the dividing step, the laser printing step, and the picking step may be arbitrarily set according to the purpose, except that the picking step is performed after the dividing step and after the laser printing step.
The thickness of the semiconductor wafer to be used as the composite sheet for forming a protective film is not particularly limited, but is preferably 30 to 1000 μm, and more preferably 100 to 400 μm in terms of easier separation into semiconductor chips to be described later.
The above-described manufacturing method is explained below with reference to the drawings. Fig. 7 is a sectional view for schematically illustrating a method of manufacturing a semiconductor chip according to an embodiment of the present invention. Here, an example of a manufacturing method in the case where the composite sheet for forming a protective film is the composite sheet for forming a protective film shown in fig. 1 will be described.
The production method of the present embodiment (which may be referred to as "production method (1)" in the present specification) includes: a step (attaching step) of attaching a film for forming a protective film in the composite sheet for forming a protective film to a semiconductor wafer; a step (protective film forming step) of curing the protective film forming film attached to the semiconductor wafer to form a protective film; a step (dividing step) of dividing the semiconductor wafer and cutting the protective film to obtain a plurality of semiconductor chips each including the cut protective film; and a step (picking-up step) of separating the semiconductor chip provided with the cut protective film from the support sheet and picking up the semiconductor chip, and further, the laser printing step (a step of irradiating the protective film-forming film or the protective film with laser light and printing the laser printing) is provided between the attaching step and the picking-up step.
When the composite sheet 101 for forming a protective film shown in fig. 1 is used, in the production method (1), a step of removing the release film 15 from the film 101 for forming a protective film (hereinafter, sometimes abbreviated as "release step") is performed as shown in fig. 7A before the above-mentioned attaching step.
For convenience, the composite sheet for forming a protective film after removing the release film 15 is also denoted by reference numeral 101.
As described above, peeling electrification of the composite sheet 101 for forming a protective film after removing the peeling film 15 is suppressed.
In the sticking step after the peeling step in the manufacturing method (1), as shown in fig. 7B, the protective film 13 in the composite sheet 101 for forming a protective film from which the peeling film 15 has been removed is stuck to the back surface 9B of the semiconductor wafer 9.
In the attaching step, the protective film forming film 13 is heated and softened, and is attached to the semiconductor wafer 9.
Note that, in the semiconductor wafer 9, bumps and the like on the circuit surface are not shown.
As described above, after the peeling step, peeling electrification of the protective film forming composite sheet 101 is suppressed. Therefore, foreign matter is prevented from entering between the film 13 for forming a protective film and the semiconductor wafer 9 after the attachment step. More specifically, no foreign matter is observed or the number of foreign matters observed between the first surface 13a of the protective film forming film 13 and the back surface 9b of the semiconductor wafer 9 is very small.
In the protective film forming step after the attachment step of the manufacturing method (1), the protective film forming film 13 attached to the semiconductor wafer 9 is thermally cured to form a protective film 13' as shown in fig. 7C. At this time, when the protective film forming film 13 is thermosetting, the protective film 13' is formed by heating the protective film forming film 13. When the protective film forming film 13 is energy ray-curable, the protective film 13' is formed by irradiating the protective film forming film 13 with an energy ray through the support sheet 10.
Here, the composite sheet for forming a protective film after the protective film 13 becomes the protective film 13 'is denoted by reference numeral 101'. This is also the same in the following figures.
In the protective film forming step, the curing conditions of the protective film forming film 13, that is, the heating temperature and heating time in the thermal curing, and the illuminance and light amount of the energy ray in the energy ray curing are the same as those described above.
In the dividing step after the protective film forming step of the manufacturing method (1), the semiconductor wafer 9 is divided and the protective film 13 ' is cut, and as shown in fig. 7D, a plurality of semiconductor chips 9 ' each including the cut protective film 130 ' are obtained. At this time, the protective film 13 'is cut (divided) at a position along the peripheral edge of the semiconductor chip 9'.
In the dividing step, the method of dividing the semiconductor wafer 9 and cutting the protective film 13' may be a known method.
Examples of such a method include: a method of dividing (cutting) the semiconductor wafer 9 together with the protective film 13' by using a dicing blade; and a method of irradiating the semiconductor wafer 9 with laser light so as to be focused at a focal point set in the semiconductor wafer 9 to form a modified layer in the semiconductor wafer 9, spreading the semiconductor wafer 9 on which the modified layer is formed and the protective film 13 'is attached to the back surface 9b in the surface direction of the protective film 13' together with the protective film 13 ', and cutting the protective film 13' and dividing the semiconductor wafer 9 at the modified layer.
In the pickup step after the dividing step in the manufacturing method (1), as shown in fig. 7E, the semiconductor chip 9 'provided with the cut protective film 130' is separated from the support sheet 10 and picked up. The direction of the pick-up is indicated by an arrow I, which is the same in the following figures. Examples of the separation tool 8 for separating the semiconductor chip 9 'together with the protective film 130' from the support sheet 10 include a vacuum nozzle (vacuum collet).
Thereby, the semiconductor chip 9' as a target is obtained as a semiconductor chip with a protective film.
The semiconductor chip with a protective film obtained by the manufacturing method (1) has excellent characteristics in which foreign matter is prevented from entering between the protective film 130 'and the semiconductor chip 9'.
In the laser printing step after the attaching step of the production method (1) and before the pickup step, the protective film-forming film or the protective film is irradiated with a laser beam, and laser printing is performed on the protective film-forming film or the protective film. When laser printing is performed on the protective film, laser printing may be performed on either the protective film 13 'before cutting or the protective film 130' after cutting.
In the laser printing step, the protective film-forming film or the protective film is irradiated with a laser beam through the support sheet.
In the laser printing step, the laser printing may be performed, for example, at a wavelength: 532nm, frequency: 20kHz, printing speed: 100 mm/sec, power: under the condition of 0.24W.
In the manufacturing method (1), the dividing step is performed after the protective film forming step, but in the manufacturing method of the semiconductor chip of the present embodiment, the dividing step may be performed without performing the protective film forming step, and the protective film forming step may be performed after the dividing step (this embodiment may be referred to as "manufacturing method (2)").
That is, the production method (2)) of the present embodiment includes: a step (attaching step) of attaching a film for forming a protective film in the composite sheet for forming a protective film to a semiconductor wafer; a step (dividing step) of dividing the semiconductor wafer and cutting the protective film forming film to obtain a plurality of semiconductor chips each including the cut protective film forming film; a step (protective film forming step) of forming a protective film by curing the protective film forming film (the cut protective film forming film) attached to the semiconductor wafer; a step (picking-up step) of separating the semiconductor chip provided with the protective film after cutting (cut) from the support sheet and picking up the semiconductor chip, and further, the laser printing step (a step of irradiating the protective film with laser light and printing the protective film) is provided between the attaching step and the picking-up step.
Fig. 8 is a sectional view for schematically illustrating one embodiment of a method for manufacturing such a semiconductor chip.
As shown in fig. 8A to 8B, the peeling step and the sticking step of the production method (2) can be performed by the same methods as those of the production method (1), respectively (shown in fig. 7A to 7B).
In the same manner as in the manufacturing method (1), the manufacturing method (2) suppresses the mixing of foreign matter between the film 13 for forming the protective film and the semiconductor wafer 9 even after the attachment step.
In the dividing step of the manufacturing method (2), the semiconductor wafer 9 is divided, and the protective film forming film 13 is cut, so that a plurality of semiconductor chips 9' each including the cut protective film forming film 130 are obtained as shown in fig. 8C. At this time, the protective film forming film 13 is cut (divided) at a position along the peripheral edge portion of the semiconductor chip 9'. The cut protective film forming film 13 is denoted by reference numeral 130.
In the protective film forming step of the manufacturing method (2), the protective film forming film 130 is cured, and as shown in fig. 8D, the protective film 130 'is formed on the semiconductor chip 9'.
The protective film forming step in the production method (2) can be performed by the same method as the protective film forming step in the production method (1).
By performing this step, a semiconductor chip with a protective film can be obtained after the end of the dividing step in the manufacturing method (1), that is, in the same state as that in fig. 7 (d).
In the pickup step of the manufacturing method (2), as shown in fig. 8E, the semiconductor chip 9 'provided with the cut protective film 130' is separated from the support sheet 10 and picked up.
The pickup step in the production method (2) can be performed by the same method as the pickup step in the production method (1) (as shown in fig. 8E).
Thereby, the semiconductor chip 9' as a target is obtained as a semiconductor chip with a protective film.
The semiconductor chip with a protective film obtained by the manufacturing method (2) has excellent characteristics in which foreign matter is prevented from entering between the protective film 130 'and the semiconductor chip 9'.
In the laser printing step after the attaching step of the production method (2) and before the pickup step, the protective film-forming film or the protective film is irradiated with laser light, and laser printing is performed on the protective film-forming film or the protective film. When laser printing is performed on the protective film forming film, laser printing may be performed on either the protective film forming film 13 before cutting or the protective film forming film 130 after cutting.
In the laser printing step, the protective film-forming film or the protective film is irradiated with a laser beam through the support sheet.
In the laser printing step, laser printing may be performed under the same printing conditions as in the production method (1), for example.
In the manufacturing methods (1) and (2), the pickup step is performed after the protective film forming step, but in the manufacturing method of the semiconductor chip of the present embodiment, the protective film forming step may be performed to the pickup step without performing the protective film forming step, and the protective film forming step may be performed after the pickup step (this embodiment may be referred to as "manufacturing method (3)").
That is, the production method of the present embodiment (production method (3)) comprises: a step (attaching step) of attaching a film for forming a protective film in the composite sheet for forming a protective film to a semiconductor wafer; a step (dividing step) of dividing the semiconductor wafer and cutting the protective film forming film to obtain a plurality of semiconductor chips each including the cut protective film forming film; a step (picking-up step) of separating and picking up the semiconductor chip provided with the cut protective film forming film from the support sheet; and a step (protective film forming step) of forming a protective film by curing the protective film forming film (protective film forming film after cutting and picking) adhered to the semiconductor wafer, and further, the laser printing step (step of irradiating the protective film forming film with laser light and printing the laser printing step) is provided between the adhering step and the picking step.
Fig. 9 is a sectional view for schematically illustrating one embodiment of a method for manufacturing such a semiconductor chip.
As shown in fig. 9A to 9C, the peeling step, the sticking step, and the dividing step of the manufacturing method (3) can be performed by the same methods as those of the peeling step, the sticking step, and the dividing step of the manufacturing method (2), respectively (shown in fig. 8A to 8C).
In the manufacturing method (3), as in the manufacturing method (1), foreign matter is prevented from entering between the film for forming a protective film 13 and the semiconductor wafer 9 even after the attaching step.
In the pickup step of the production method (3), as shown in fig. 9D, the semiconductor chip 9' provided with the cut protective film forming film 130 is separated from the support sheet 10 and picked up.
The pickup step in the production method (3) can be performed by the same method as the pickup step in the production methods (1) and (2) (see fig. 7E and 8E).
In the laser printing step after the attaching step of the production method (3) and before the pickup step, the protective film-forming film is irradiated with laser light, and laser printing is performed on the protective film-forming film. At this time, laser printing may be performed on either the film 13 for forming the protective film before cutting or the film 130 for forming the protective film after cutting.
In the laser printing step, the protective film-forming film is irradiated with a laser beam through the support sheet.
In the laser printing step, laser printing may be performed under the same printing conditions as in the production method (1), for example.
In the protective film forming step of the manufacturing method (3), the picked-up protective film forming film 130 is cured, and as shown in fig. 9E, a protective film 130 'is formed on the semiconductor chip 9'.
When the protective film-forming film 13 is thermosetting, the protective film-forming step in the production method (3) can be performed by the same method as the protective film-forming step in the production methods (1) and (2). When the protective film-forming film 13 is energy-ray-curable, the protective film-forming step in the production method (3) can be performed by the same method as the protective film-forming step in the production methods (1) and (2), except that it is not necessary to irradiate the protective film-forming film 130 with an energy ray through the support sheet 10.
Thereby, the semiconductor chip 9' as a target is obtained as a semiconductor chip with a protective film.
The semiconductor chip with a protective film obtained by the manufacturing method (3) has excellent characteristics in which foreign matter is prevented from entering between the protective film 130 'and the semiconductor chip 9'.
As described above, in the manufacturing methods (1) to (3), as a method of obtaining the semiconductor chips 9' by dividing the semiconductor wafer 9, a method of forming a modified layer in the semiconductor wafer 9 and dividing the semiconductor wafer 9 at the modified layer portion without using a dicing blade can be applied. In this case, in the dividing step, the step of forming the modified layer inside the semiconductor wafer 9 may be performed at any stage, for example, at any stage before the attaching step, between the attaching step and the protective film forming step, or the like, as long as the step of dividing the semiconductor wafer 9 at the modified layer portion is performed.
The method for manufacturing a semiconductor chip when using the composite sheet 101 for forming a protective film shown in fig. 1 has been described above, but the method for manufacturing a semiconductor chip according to the present embodiment is not limited thereto.
For example, the method for manufacturing a semiconductor chip according to the present embodiment can also be used to manufacture a composite sheet for forming a protective film other than the composite sheet 101 for forming a protective film shown in fig. 1, such as the composite sheets 102 to 105 for forming a protective film shown in fig. 2 to 5 and the composite sheet 301 for forming a protective film shown in fig. 6, in the same manner.
In this manner, when the composite sheet for forming a protective film according to another embodiment is used, a semiconductor chip can be manufactured by appropriately performing addition, change, deletion, and the like of the steps in the above-described manufacturing method depending on the structure of the sheet.
Manufacturing method of semiconductor device
After the semiconductor chip with the protective film is obtained by the above-described manufacturing method, the semiconductor chip is flip-chip bonded to a circuit surface of a substrate by a known method to form a semiconductor package, and a target semiconductor device (not shown) is manufactured by using the semiconductor package.
Examples
The present invention will be described in more detail below with reference to specific examples. However, the present invention is not limited to the examples shown below.
< antistatic composition >
The antistatic compositions used in the examples or comparative examples are shown below.
Antistatic composition (VI-1) -1: polypyrrole was emulsified with a reactive emulsifier and dissolved in an organic solvent to obtain a polypyrrole solution.
Antistatic composition (VI-1) -2: "UVH 515" manufactured by Idemitsu Kosan co., ltd "
< raw Material for production of composition for Forming protective film >
The raw materials used for preparing the composition for forming a protective film are shown below.
[ Polymer component (A) ]
(A) -1: acrylic resin (weight average molecular weight 400000, glass transition temperature-1 ℃ C.) obtained by copolymerizing n-butyl acrylate (10 parts by mass), methyl acrylate (70 parts by mass), glycidyl methacrylate (5 parts by mass), and 2-hydroxyethyl acrylate (15 parts by mass)
[ thermosetting component (B) ]
Epoxy resin (B1)
(B1) -1: bisphenol A type epoxy resin ("jER 1055" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight 800 to 900g/eq)
(B1) -2: bisphenol A type epoxy resin ("BPA 328" manufactured by Nippon Shokubai Co., Ltd., epoxy equivalent of 235g/eq)
(B1) -3: dicyclopentadiene type epoxy resin ("EPICLON HP-7200 HH" manufactured by DIC Corporation, epoxy equivalent weight of 274 to 286g/eq)
Heat-curing agent (B2)
(B2) -1: dicyandiamide (thermally active latent epoxy resin curing agent, "DICY 7" manufactured by Mitsubishi Chemical Corporation, active hydrogen amount of 21g/eq)
[ curing Accelerator (C) ]
(C) -1: 2-phenyl-4, 5-dihydroxymethylimidazole ("CURZOL 2 PHZ-PW" manufactured by SHIKOKU CHEMICALS CORPORATION)
[ Filler (D) ]
(D) -1: silica Filler (SC 2050MA manufactured by Admatechs Co., Ltd., silica Filler surface-modified with an epoxy compound and having an average particle diameter of 500nm)
[ colorant (I) ]
(I) -1: carbon Black (manufactured by Mitsubishi Chemical Corporation, "MA 600B")
[ example 1]
Production of composite sheet for Forming protective film
< preparation of composition for Forming thermosetting protective film (III-1) >
The polymer component (a) -1(150 parts by mass), the epoxy resin (B1) -1(10 parts by mass), the epoxy resin (B1) -2(60 parts by mass), the epoxy resin (B1) -3(30 parts by mass), the thermosetting agent (B2) -1(2.4 parts by mass), the curing accelerator (C) -1(2.4 parts by mass), the filler (D) -1(320 parts by mass), and the colorant (I) -1(1.16 parts by mass) were mixed, and the mixture was diluted with methyl ethyl ketone so that the total concentration thereof became 55% by mass, thereby preparing the thermosetting protective film-forming composition (III-1).
< production of film for Forming protective film >
The thermosetting protective film-forming composition (III-1) obtained above was applied to a release-treated surface of a polyethylene terephthalate film using a release film (SP-PET 381031 manufactured by Lintec Corporation, "38 μm thick) having one surface thereof subjected to release treatment by silicone treatment, and dried at 100 ℃ for 2 minutes, thereby producing a thermosetting protective film-forming film having a thickness of 40 μm.
< formation of antistatic layer >
As the substrate, a polypropylene substrate (thickness: 80 μm) was prepared, one surface of which had a surface roughness Ra of 0.2 μm and the other surface of which had a surface roughness Ra of less than the above value, so that the one surface was a concave-convex surface and the other surface was a smooth surface.
The antistatic composition (VI-1) -2 was coated on the uneven surface of the polypropylene-made substrate using a bar coater and dried at 50 ℃ for 1 minute, thereby forming a back antistatic layer having a thickness of 170nm on the substrate.
< preparation of adhesive composition (I-4) >
A non-energy ray-curable adhesive composition (I-4) was prepared which contained an acrylic polymer (100 parts by mass), a bisphenol a type epoxy resin ("JER 828" manufactured by Mitsubishi Chemical Corporation) (30 parts by mass in terms of the amount of the epoxy resin), and a trifunctional xylylene diisocyanate based crosslinking agent ("TAKENATE D110N" manufactured by inc. in terms of the amount of the crosslinking agent), and further contained methyl ethyl ketone as a solvent, wherein the total concentration of the acrylic polymer, epoxy resin, and crosslinking agent was 35 parts by mass. The acrylic polymer was a copolymer having a weight average molecular weight of 600000, which was obtained by copolymerizing 2-ethylhexyl acrylate (60 parts by mass), methyl methacrylate (30 parts by mass), and 2-hydroxyethyl acrylate (10 parts by mass).
< production of supporting sheet >
The adhesive composition (I-4) obtained above was coated on the release-treated surface of the release film using the same release film ("SP-PET 381031" manufactured by Lintec Corporation, 38 μm in thickness) as used in the production of the film for forming a protective film, and dried by heating at 120 ℃ for 2 minutes, thereby forming a non-energy ray-curable adhesive layer having a thickness of 5 μm.
Next, the exposed surface of the adhesive layer in the laminate of the release film and the adhesive layer (in other words, the surface of the adhesive layer opposite to the release film side) was bonded to the exposed surface of the substrate in the laminate of the substrate and the back antistatic layer obtained above (in other words, the surface of the substrate opposite to the back antistatic layer side). Thus, a support sheet with a release film was produced, in which the back antistatic layer, the base material, the adhesive layer, and the release film were laminated in this order in the thickness direction.
< production of composite sheet for Forming protective film >
In the support sheet obtained above, the release film was removed. Then, the exposed surface of the newly produced adhesive layer in the support sheet (in other words, the surface of the adhesive layer opposite to the substrate side) is bonded to the exposed surface of the protective film forming film in the laminate of the release film and the protective film forming film obtained above (in other words, the surface of the protective film forming film opposite to the release film side). Thus, a composite sheet for forming a protective film was obtained, in which a back antistatic layer (thickness: 170nm), a base material (thickness: 80 μm), an adhesive layer (thickness: 5 μm), a film for forming a protective film (thickness: 40 μm), and a release film (thickness: 38 μm) were laminated in this order in the thickness direction thereof. In this composite sheet for forming a protective film, the planar shape of the laminate of the back antistatic layer, the base material, and the adhesive layer (in other words, the support sheet) was a circle with a diameter of 270mm, and the planar shape of the laminate of the protective film-forming film and the release film was a circle with a diameter of 210mm, and these two circles were made concentric.
Next, the release film is removed, and the adhesive layer for a jig is provided on a region in the vicinity of the peripheral edge portion of the film for forming a protective film, on the exposed surface of the film for forming a protective film (in other words, the surface of the film for forming a protective film opposite to the adhesive agent layer side, or the first surface).
Next, on the first surface of the film for forming a protective film and the first surface of the adhesive layer for a jig, a release film (SP-PET 381031 manufactured by Lintec Corporation, thickness 38 μm) identical to the release film removed previously was attached.
Thus, a composite sheet for forming a protective film with a release film was produced, which had the structure shown in fig. 2 and had a size of the film for forming a protective film slightly smaller than that of the support sheet.
The layers constituting the composite sheet for forming a protective film are shown in table 1. The term "-" in the column of the layer means that the composite sheet for forming a protective film does not have the layer.
Evaluation of composite sheet for Forming protective film
< measurement of surface resistivity of composite sheet for protective film formation before thermal curing of protective film-forming film >
The surface Resistivity of the exposed surface of the back surface antistatic layer on the side opposite to the base material in the composite sheet for forming a protective film obtained above was measured using a surface resistance tester ("R12704 resistance chamber" manufactured by ADVANTEST CORPORATION) with the applied voltage set at 100V without thermosetting the film for forming a protective film. The results are shown in table 1 under the column "surface resistivity before thermal curing (Ω/□) of the composite sheet for forming a protective film".
< measurement of surface resistivity of composite sheet for protective film formation after thermal curing of protective film-forming film >
The composite sheet for forming a protective film, in which the surface resistivity before heat curing was measured, was used, and the film for forming a protective film was heat-cured at 130 ℃ for 2 hours. Then, the surface resistivity of the back surface antistatic layer in the composite sheet for forming a protective film after heat curing was measured by the same method as described above. The results are shown in table 1 under the column "surface resistivity (Ω/□) after thermal curing of the composite sheet for forming a protective film".
< confirmation of Effect of suppressing contamination of foreign matter between film for forming protective film and semiconductor wafer >
The composite sheet with a release film for forming a protective film was observed with the naked eye from the outermost layer on the base material side of the composite sheet with a release film for forming a protective film obtained above, that is, from the side of the back antistatic layer, and further observed with a digital microscope ("VE-8000" manufactured by KEYENCE CORPORATION). Then, it was confirmed that foreign matter having a maximum length of 0.5mm or more was not present between the protective film forming film and the release film over the entire regions of the protective film forming film and the release film.
Then, the release film was peeled (removed) from the composite sheet with a release film for protective film formation using a sheet mounter ("RAD-2500" manufactured by linetec Corporation), and the exposed surface (in other words, the first surface) of the film for protective film formation in the composite sheet for protective film formation was immediately attached to the polished surface of an 8-inch silicon wafer (thickness 350 μm), and the exposed surface (in other words, the first surface) of the adhesive layer for jig was attached to the surface of the ring frame, to obtain a composite sheet for protective film formation and a laminate of silicon wafers.
Then, the laminate was observed with the naked eye from the outermost layer on the base material side of the obtained laminate, that is, the back surface antistatic layer side, and further observed with a digital microscope ("VE-8000" manufactured by KEYENCE CORPORATION), and it was confirmed whether or not foreign matter was mixed between the protective film-forming film and the silicon wafer over the entire area of the silicon wafer. When the foreign matter was mixed, the composite sheet for forming the protective film was peeled off from the silicon wafer, and the maximum length of the foreign matter was measured by using the digital microscope. Then, the effect of suppressing the contamination of foreign substances was evaluated according to the following evaluation criteria. The results are shown in Table 1.
(evaluation criteria)
A: there is no foreign matter with the maximum length of more than 0.5 mm.
B: there are 1-3 foreign bodies with the maximum length of more than 0.5 mm.
C: there are more than 4 pieces of foreign matters with the maximum length of more than 0.5 mm.
In the present evaluation item, the "maximum length of the foreign matter" means: in an observed object image of a digital microscope, when 2 points which are arbitrarily different from each other are selected on the surface of a foreign object and the length of a line segment connecting the 2 points is measured, the length of the longest line segment among the foreign objects is measured.
< measurement of Total light transmittance of support sheet >
The total light transmittance (%) of the support sheet obtained above was measured using UV-VIS-NIR SPECTROPHOTOMETER UV-3600 (manufactured by Shimadzu Corporation) according to JIS K7375: 2008. The results are shown in Table 1.
< measurement of haze of supporting sheet >
The haze (%) of the support sheet obtained as described above was measured according to JIS K7136: 2000 using NDH5000 (manufactured by Nippon Denshoku Industries co., ltd.) and a white LED (5V, 3W) as a light source. The results are shown in Table 1.
< evaluation of laser printing visibility of protective film >
The release film was removed from the protective film-forming composite sheet obtained above, and the exposed surface (in other words, the first surface) of the protective film-forming film thus produced was attached to the back surface of an 8-inch silicon wafer. The attachment at this time was performed using a chip mounter ("RAD 2700" manufactured by Lintec Corporation). In this way, a first laminated structure was produced in which the substrate, the adhesive layer, the protective film-forming film, and the silicon wafer were laminated in this order in the thickness direction thereof.
Then, using a laser printing apparatus ("CSM 300M" manufactured by EO technologies co., ltd.), a laser beam with a wavelength: 532nm, frequency: under the condition of 20kHz, the surface (in other words, the second surface) on the adhesive agent layer side of the protective film-forming film was irradiated with laser light through the support sheet, and printing was performed. At this time, characters of 0.3mm × 0.2mm in size were printed at a printing speed of 100 mm/sec.
Then, the protective film-forming film was observed for printing (laser printing) at a magnification of 100 times through a support sheet using a digital microscope ("VHS-1000" manufactured by KEYENCE CORPORATION), and the visibility of the printing (characters) was evaluated according to the following criteria. The results are shown in Table 1. The laser printing visibility of the protective film-forming film evaluated here was regarded as equivalent to that of the protective film.
A: the printing is clear and can be easily recognized.
B: the printed characters were slightly blurred and could not be easily recognized.
C: the printed characters are not clear and can not be identified.
< production of composite sheet for Forming protective film >
[ example 2]
A composite sheet for forming a protective film was produced in the same manner as in example 1, except that the coating amount of the antistatic composition (VI-1) -2 was changed so that the thickness of the back surface antistatic layer was changed to 50nm instead of 170 nm. The composite sheet for forming a protective film produced in this example was: a composite sheet for forming a protective film with a release film, which comprises a back antistatic layer (thickness: 50nm), a base material (thickness: 80 μm), an adhesive layer (thickness: 5 μm), a film for forming a protective film (thickness: 40 μm), and a release film (thickness: 38 μm) laminated in this order in the thickness direction, was constituted as shown in FIG. 2, and the size of the film for forming a protective film was slightly smaller than that of the support sheet.
The results are shown in Table 1.
Evaluation of composite sheet for Forming protective film
The composite sheet for forming a protective film obtained as described above was evaluated by the same method as in example 1. The results are shown in Table 1.
Comparative example 1
A composite sheet for protective film formation was produced and evaluated in the same manner as in example 1, except that the antistatic composition (VI-1) -1 was used in place of the antistatic composition (VI-1) -2, the amount of the antistatic composition (VI-1) -1 applied was changed to make the thickness of the back antistatic layer 75nm in place of 170nm, and drying of the back antistatic layer was performed at 100 ℃ for 2 minutes. The composite sheet for forming a protective film produced in this comparative example was: a composite sheet for forming a protective film with a release film, which comprises a back antistatic layer (thickness: 75nm), a base material (thickness: 80 μm), an adhesive layer (thickness: 5 μm), a film for forming a protective film (thickness: 40 μm), and a release film (thickness: 38 μm) laminated in this order in the thickness direction, was constituted as shown in FIG. 2, and the size of the film for forming a protective film was slightly smaller than that of the support sheet.
The results are shown in Table 1.
Comparative example 2
A protective film-forming composite sheet was produced and evaluated in the same manner as in example 1, except that the back surface antistatic layer was not formed. The composite sheet for forming a protective film produced in this comparative example was: the composite sheet for forming a protective film further comprising a pressure-sensitive adhesive layer for a jig, which is composed of a base material (having a thickness of 80 μm), an adhesive layer (having a thickness of 5 μm), a film for forming a protective film (having a thickness of 40 μm), and a release film (having a thickness of 38 μm) laminated in this order in the thickness direction thereof, was a composite sheet for forming a protective film with a release film which did not comprise a back surface antistatic layer and had a size of the film for forming a protective film slightly smaller than that of the support sheet in fig. 2.
The results are shown in Table 1.
[ Table 1]
Figure BDA0003097626660000921
From the above results, it was found that in the composite sheets for forming a protective film of examples 1 to 2, the surface resistivity of the back surface antistatic layer was 2.8 × 10 before the film for forming a protective film was thermally cured8～4.1
×108Omega/□, the surface resistivity of the back side antistatic layer after the film for forming the protective film was thermally cured was 1.7X 109～5.3×109Omega/□, the composite sheet for forming the protective film has excellent antistatic property in ordinary period. In addition, when the composite sheet for forming the protective film is used, the foreign matter is prevented from being mixed between the film for forming the protective film and the semiconductor wafer.
The total light transmittance of the support sheet in the composite sheets for forming a protective film of examples 1 to 2 was 85% or more (91%) and the haze was 43% or less (36 to 37%), and these composite sheets were excellent in the visibility of laser printing of the protective film through the support sheet.
In contrast, the total light transmittance of the support sheet in the composite sheet for forming a protective film of comparative example 1 was less than 85% (80%) and the haze was more than 43% (47%), and the visibility of laser printing of the protective film through the support sheet was inferior to that of the composite sheets for forming a protective film of examples 1 to 2.
In the composite sheet for forming a protective film of comparative example 2, the surface resistivity of the back surface antistatic layer was 5.0 × 10 before the film for forming a protective film was thermally cured15Omega/□, the surface resistivity of the back side antistatic layer after the film for forming the protective film was thermally cured was 5.6X 1015Omega/□, the antistatic property of the composite sheet for forming the protective film is poor in ordinary times. In addition, when these composite sheets for forming a protective film are used, the mixing of foreign matters between the film for forming a protective film and the semiconductor wafer cannot be suppressed. In addition, the haze of the support sheet in the composite sheet for forming a protective film of comparative example 2 was more than 43% (47%), and the visibility of laser printing of the protective film through the support sheet was inferior to that of the composite sheets for forming a protective film of examples 1 to 2.
Industrial applicability
The invention can be used for manufacturing semiconductor devices.
Description of the reference numerals
101. 102, 103, 104, 105, 301: a composite sheet for forming a protective film; 10. 20, 50: a support sheet; 10a, 20a, 50 a: a first side of the support sheet; 11: a substrate; 11 a: a first side of the substrate; 11 b: a second side of the substrate; 12: an adhesive layer; 13. 23: a protective film-forming film; 130: a film for forming a protective film after cutting; 13': a protective film; 130': a cut-off protective film; 15: stripping the film; 16: an adhesive layer for a jig; 17: a back antistatic layer; 18: an intermediate layer; 19: a surface antistatic layer; 9: a semiconductor wafer; 9 b: a back side of the semiconductor wafer; 9': a semiconductor chip.

Claims (5)

1. A composite sheet for forming a protective film, comprising a support sheet and a film for forming a protective film formed on one surface of the support sheet,
the support sheet is provided with a base material and an antistatic layer formed on one or both surfaces of the base material,
the total light transmittance of the supporting sheet is more than 85 percent,
the surface resistivity of the composite sheet for forming the protective film is 1.0 x 1011Omega/□ or less.
2. The composite sheet for forming a protective film according to claim 1, wherein the haze of the support sheet is 43% or less.
3. A composite sheet for forming a protective film, comprising a support sheet and a film for forming a protective film formed on one surface of the support sheet,
the support sheet is provided with a base material and an antistatic layer formed on one or both surfaces of the base material,
the haze of the support sheet is 43% or less,
the surface resistivity of the composite sheet for forming the protective film is 1.0 x 1011Omega/□ or less.
4. The composite sheet for forming a protective film according to any one of claims 1 to 3, wherein the antistatic layer has a thickness of 200nm or less.
5. A method for manufacturing a semiconductor chip, comprising:
a step of attaching a film for forming a protective film in the composite sheet for forming a protective film according to any one of claims 1 to 4 to a semiconductor wafer;
forming a protective film by curing the protective film-forming film attached to the semiconductor wafer;
cutting the semiconductor wafer and cutting the protective film or the film for forming the protective film to obtain a plurality of semiconductor chips each including the cut protective film or the film for forming the protective film; and
separating and picking up the semiconductor chip provided with the cut protective film or the film for forming the protective film from the support sheet,
the manufacturing method further includes a step of irradiating the protective film-forming film or the protective film with a laser beam to print characters between the step of attaching and the step of picking up.
CN201980079821.XA 2018-12-05 2019-11-27 Composite sheet for forming protective film and method for manufacturing semiconductor chip Pending CN113261091A (en)

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