CN115132638A

CN115132638A - Protective film forming film, protective film forming sheet, protective film forming composite sheet, and device manufacturing method

Info

Publication number: CN115132638A
Application number: CN202210305547.7A
Authority: CN
Inventors: 中石康喜; 佐藤明德; 稻男洋一; 山下茂之
Original assignee: Lintec Corp
Current assignee: Lintec Corp
Priority date: 2021-03-25
Filing date: 2022-03-25
Publication date: 2022-09-30
Also published as: JP2022149802A; KR20220133795A; TW202303638A

Abstract

The invention provides a protective film forming film with high printing identification performance even though the protective film forming film is subjected to a heating process such as reflow soldering treatment, and a protective film with the protective film forming filmA method for manufacturing a device comprising a sheet for forming, a composite sheet for forming a protective film, a workpiece with a protective film, and the like. The protective film forming film is used for forming a protective film, wherein the protective film forming film comprises a printing penetrating layer and a printing recognition layer, and is CIE1976L ^* a ^* b ^* The color difference between the print penetrating layer and the print recognition layer after heating at 260 ℃ for 5 minutes in the color space is 50 or more.

Description

Protective film forming film, protective film forming sheet, protective film forming composite sheet, and device manufacturing method

Technical Field

The present invention relates to a protective film forming film, a protective film forming sheet, a protective film forming composite sheet, a work with a protective film, and a method for manufacturing a device. In particular, the present invention relates to a protective film forming film suitable for protecting a workpiece such as a semiconductor wafer or a processed product such as a semiconductor chip obtained by processing the workpiece, a protective film forming sheet provided with the protective film forming film, a composite sheet for forming a protective film, a processed product of a workpiece provided with a protective film, and a method for manufacturing an apparatus provided with a semiconductor chip or the like.

Background

In recent years, a so-called flip-chip (face down) mounting method has been used to manufacture a semiconductor device. In the flip chip system, a semiconductor chip having electrodes such as bumps (bumps) on a circuit surface is used, and the electrodes are bonded to a substrate. Therefore, the back surface of the semiconductor chip opposite to the circuit surface may be exposed.

A resin film made of 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 mounted on a semiconductor device. The protective film is used for preventing the semiconductor chip from edge breakage such as cracks or defects in the dicing process and the subsequent processes.

In order to identify the semiconductor chip, a mark, a character, or the like is marked on the surface of the protective film by, for example, laser printing. In this laser printing, the surface of the protective film is cut with a laser beam to change the surface state of the protective film, and a print is formed with a contrast with an uncut portion.

Patent document 1 describes a dicing tape-integrated film for semiconductor back surface, which has a multilayer structure including a wafer adhesive layer and a laser mark layer. This document also describes the following: since the flip-chip semiconductor back surface film is bonded with the wafer adhesive layer with excellent adhesiveness, floating or the like due to poor adhesion is not caused, and since the laser marking layer is the outermost layer, various information such as character information or graphic information can be provided with excellent marking property.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 5885325

Disclosure of Invention

Technical problem to be solved by the invention

However, when the semiconductor chip with the protective film is mounted on the substrate by the flip chip method, the chip with the protective film and the substrate are electrically and mechanically joined by a heating process such as reflow soldering. The print portion formed by laser printing may be deformed by the heating step. The surface state of the print portion changes due to the above deformation, and the contrast between the print portion and the portion other than the print portion is lowered. As a result, there is a problem that the visibility of the printed matter after the heating step is reduced as compared with that immediately after the laser printing is completed. In particular, since the size of printed characters becomes finer as the miniaturization of chips progresses, there is a problem in miniaturized chips with protective films.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a protective film forming film having high print visibility even when subjected to a heating step such as reflow soldering, a protective film forming sheet and a protective film forming composite sheet each including the protective film forming film, and a method for manufacturing a device such as a semiconductor device.

Means for solving the problems

The scheme of the invention is as follows.

[1] A protective film forming film for forming a protective film, wherein,

the protective film forming film has a print penetrating layer and a print recognizing layer, and is represented by CIE1976L ^* a ^* b ^* In color space, at 260 deg.CThe color difference between the printing penetrating layer and the printing identification layer after heating for 5 minutes is more than 50.

[2] The protective film forming film according to [1], wherein the protective film forming film is composed of a print penetrating layer and a print recognizing layer.

[3] The protective film forming film according to [1] or [2], wherein the thickness of the print-through layer is 5 μm or less.

[4]According to [1]～[3]The protective film forming film of any one of the above, wherein CIE1976L of the print recognition layer ^* a ^* b ^* L in color space ^* Is 50 or more.

[5]According to [4 ]]The protective film is formed into a film, wherein CIE1976L of the printing recognition layer ^* a ^* b ^* A in color space ^* Is 40 or more.

[6]According to [1]]～[4]The protective film forming film of any one of the above, wherein the print recognition layer has CIE1976L ^* a ^* b ^* B in color space ^* Is 30 or more.

[7] A protective film-forming sheet comprising the protective film-forming film according to any one of [1] to [6] and a release film arranged so as to be releasable on at least one main surface of the protective film-forming film.

[8] A composite sheet for forming a protective film, comprising a support sheet and the protective film forming film according to any one of [1] to [6] formed on the support sheet.

[9] A kit comprising a print recognition layer for affixing to a workpiece and a laminate comprising a support sheet and a print-through layer formed on the support sheet for affixing to the print recognition layer,

in CIE1976L ^* a ^* b ^* The color difference between the print penetrating layer and the print recognition layer after heating at 260 ℃ for 5 minutes in the color space is 50 or more.

[10] A method for manufacturing a device, comprising the steps of:

a step of attaching the protective film-forming film of the protective film-forming sheet according to [7] or the protective film-forming film of the composite sheet for protective film formation according to [8] to the back surface of a workpiece;

forming the attached protective film into a protective film;

a step of laser marking the protective film or the protective film forming film;

obtaining a plurality of workpiece processed objects with a protective film or a protective film forming film by singulating the workpiece having the protective film or the protective film forming film on the back surface;

disposing a workpiece with a protective film or a protective film forming film on a substrate;

and heating the workpiece with the protective film and the substrate arranged on the substrate.

[11] A work piece with a protective film, wherein a protective film obtained by forming the protective film according to any one of [1] to [6] into a protective film is formed.

Effects of the invention

According to the present invention, it is possible to provide a protective film forming film having high visibility of printing even when subjected to a heating step such as reflow processing, a protective film forming sheet and a protective film forming composite sheet each including the protective film forming film, and a method for manufacturing a device such as a semiconductor device.

Drawings

Fig. 1 is a schematic sectional view of one example of the protective film forming film of the present embodiment.

Fig. 2 is a schematic sectional view for explaining a printed portion formed by laser printing of a protective film obtained by forming a protective film forming film of the present embodiment into a protective film.

Fig. 3 is a top view of the schematic cross-sectional view shown in fig. 2.

Fig. 4 is a schematic cross-sectional view of an example of a chip having a protective film obtained by forming a protective film forming film into a protective film.

Fig. 5A is a schematic sectional view of an example of the protective film-forming sheet of the present embodiment.

Fig. 5B is a schematic sectional view of another example of the protective film-forming sheet of the present embodiment.

Fig. 6A is a schematic cross-sectional view of an example of the composite sheet for forming a protective film according to the present embodiment.

Fig. 6B is a schematic sectional view of another example of the composite sheet for forming a protective film according to the present embodiment.

Fig. 7 is a schematic sectional view for explaining a step of attaching the composite sheet for forming a protective film of the present embodiment to a wafer.

Fig. 8 is a schematic cross-sectional view for explaining a process of singulating the wafer with the protective film.

Fig. 9 is a schematic sectional view for explaining a step of disposing a chip with a protective film on a substrate.

Description of the reference numerals

10: forming a film by the protective film; 2: printing a penetrating layer; 3: a print recognition layer; 61. 62: a protective film-forming sheet; 71. 72: a composite sheet for forming a protective film; 80: a chip with a protective film; 1: and (5) protecting the film.

Detailed Description

The present invention will be described in detail below with reference to specific embodiments and drawings. First, main terms used in the present specification will be described.

The work is a plate-like body to which the support sheet or the composite sheet for forming a protective film of the present embodiment is attached and processed. Examples of the workpiece include a wafer and a panel. Specifically, a semiconductor wafer and a semiconductor panel are exemplified. Examples of the workpiece processed object include a wafer and a chip obtained by singulating the wafer. Specifically, a semiconductor wafer is singulated to obtain semiconductor chips. At this time, the protective film is formed on the back surfaces of the wafer and the chip.

The "front surface" of a workpiece such as a wafer refers to a surface on which a circuit, a convex electrode such as a bump, and the like are formed, and the "back surface" refers to a surface on which a circuit, an electrode (for example, a convex electrode such as a bump) and the like are not formed.

The singulation of the wafer refers to obtaining chips by dividing the wafer according to the circuit.

In this specification, "printed characters" include characters, symbols, figures, and the like.

In the present specification, "(meth) acrylate" is used as a term indicating both "acrylate" and "methacrylate", and other similar terms are also used.

The "energy ray" means ultraviolet rays, electron beams, and the like, and preferably ultraviolet rays.

The release film is a film that supports the adhesive layer or the protective film forming film in a releasable manner. The film does not limit the thickness, and is also used as a concept of a sheet.

The mass ratio in the description of the composition such as the composition for forming a protective film is based on the active ingredient (solid content), and the solvent is not included unless otherwise specified.

(1. protective film forming film)

The protective film forming film of the present embodiment is attached to a workpiece, and is used for forming a protective film for protecting the workpiece or a workpiece processed object.

As shown in fig. 1, the protective film forming film 10 has: the print through layer 2 of the portion irradiated with the laser beam and the print recognition layer 3 of the portion corresponding to the portion irradiated with the laser beam of the print through layer 2 are removed by laser printing. The protective film forming film may have a layer other than the print-through layer and the print recognition layer, but in the present embodiment, the protective film forming film is preferably composed of two layers, that is, the print-through layer and the print recognition layer.

The thickness of the protective film-forming film is not particularly limited, but is preferably 100 μm or less, 70 μm or less, 45 μm or less, or 30 μm or less. The thickness of the protective film forming film is preferably 5 μm or more, 10 μm or more, and 15 μm or more. If the thickness of the protective film forming film is within the above range, the protective performance of the obtained protective film is good. The thickness of the protective film forming film is the total thickness of all layers constituting the protective film forming film.

The thickness of the print penetration layer is preferably 5 μm or less, more preferably 3 μm or less, and still more preferably 1 μm or less. When the thickness of the print penetrating layer is within the above range, the time for penetrating the print penetrating layer with the laser can be shortened, and thus the printing speed can be improved.

In fig. 1, a main surface 3a of the print recognition layer 3 is stuck to the back surface of the workpiece or workpiece, and a main surface 2b of the print penetration layer 2 is an outermost layer exposed to the outside.

(1.1 color difference between print through layer and print recognition layer)

In the present embodiment, the color difference Δ E between the print penetrating layer and the print discriminating layer after heating at 260 ℃ for 5 minutes ^* _ab Is 50 or more. In using CIE1976L ^* a ^* b ^* L in color space ^* 、a ^* 、b ^* Let the color coordinate of the printing penetration layer be (L) ^* ₁ 、a ^* ₁ 、b ^* ₁ ) Let the color coordinate of the print recognition layer be (L) ^* ₂ 、a ^* ₂ 、b ^* ₂ ) At Δ E ^* _ab ＝[(L ^* ₁ -L ^* ₂ ) ² +(a ^* ₁ -a ^* ₂ ) ² +(b ^* ₁ -b ^* ₂ ) ² ] ^1/2 Denotes Δ E ^* _ab 。

When the color difference is within the above range, the visibility of the print penetrating layer and the print recognizing layer is improved. Color difference Δ E ^* _ab Preferably 60 or more, more preferably 70 or more. On the other hand, the color difference Δ E is easy to manufacture ^* _ab The upper limit of (2) is, for example, about 100.

As shown in fig. 2, in the print penetration layer 2, when the protective film 1 is laser-printed, the portion irradiated with the laser is completely removed. That is, after laser printing, the portion irradiated with the laser light penetrates the print penetration layer 2 from the one main surface 2a to the other main surface 2b, and the print recognition layer 3 corresponding to the portion irradiated with the laser light is exposed to the outside and can be observed from the outside. Therefore, as shown in fig. 3, by performing laser printing on the protective film, the print recognition layer 3 is exposed in the form of print at the background portion constituted by the print penetration layer 2, and since the color difference between the print penetration layer 2 and the print recognition layer 3 is controlled within the above range, it is possible to clearly recognize the print formed on the protective film 1.

Since the visibility of printing is realized by the color of the print recognition layer, the color of the print recognition layer does not change even after a heating step such as reflow treatment after printing, unlike printing based on a difference in the surface state of the protective film. Therefore, even after the heating step such as reflow soldering, the visibility of the printing formed on the protective film can be kept high.

Further, since the print is formed by the exposure of the print recognition layer, the print can be recognized sufficiently even if the print width is narrowed. Therefore, very fine laser printing can be realized.

The portion irradiated with the laser beam may penetrate the print-penetrating layer, and the surface of the print recognition layer may be removed to a predetermined depth or not.

Further, when the color difference is within the above range, the color of the print through layer and the color of the print recognition layer can be freely combined, and hence the design of the chip with the protective film can be improved. In printing based on the difference in the surface state of the protective film, the printed portion is whitened compared with other portions only by a physical shape change, and the combination of colors is very limited.

Further, when the print recognition layer is formed of a plurality of layers having different colors, the removal depth of the print recognition layer can be changed by adjusting the output power of the laser light, and printing can be formed of a plurality of colors.

In order to cover the back surface of the chip, the protective film is often colored black or gray close to black. Therefore, the print-through layer as the outermost layer of the protective film is preferably colored black or gray close to black. As an example, L is preferably printed through the layer ^* ₁ Satisfies the range of 0 to 30, a ^* ₁ Satisfies the range of-10 to 10, b ^* ₁ The range of-10 to 10 is satisfied. In this case, in order to easily control the color difference between the print-penetrating layer and the print-recognizing layer within the above range, it is preferable that L of the print-recognizing layer is set to be equal to or smaller than L ^* ₂ Is set to 50 or more, more preferably 65 or more, and still more preferably 80 or more. On the other hand, L is L from the viewpoint of ease of manufacture ^* ₂ The upper limit of (2) is, for example, about 100.

In order to further improve the visibility, it is preferable to print the identification layer a ^* ₂ Is 40 or more, more preferably 50 or more, and still more preferably 55 or more. On the other hand, from the viewpoint of ease of production, a ^* ₂ The upper limit of (b) is, for example, about 80.

In addition, in order to further improve the visibility, it is preferable to print the identification layer b ^* ₂ Is 30 or more, more preferably 60 or more, and still more preferably 80 or more. On the other hand, from the viewpoint of ease of production, b ^* ₂ The upper limit of (2) is, for example, about 100.

(1.2 protective film)

In the present embodiment, the protective film is obtained by forming the protective film forming film of the present embodiment into a protective film.

"making a protective film" means making a protective film forming film into a state having sufficient characteristics for protecting a workpiece or a workpiece processed article. Specifically, when the protective film forming film of the present embodiment is curable, "to produce a protective film" means that an uncured protective film forming film is produced into a cured product. In other words, the protective film forming film after the protective film is formed is a cured product of the protective film forming film, and is different from the protective film forming film.

After the work is superposed on the curable protective film forming film, the protective film forming film is cured, whereby the protective film can be firmly adhered to the work, and a protective film having durability can be formed.

On the other hand, when the protective film forming film of the present embodiment is used in a non-cured state without containing a curable component, the protective film forming film of the present embodiment is formed as a protective film from the time when the protective film forming film is attached to a workpiece. In other words, the protective film forming film after the protective film is formed is the same as the protective film forming film.

When high protective performance is not pursued, it is not necessary to cure the protective film-forming film, and therefore the protective film-forming film is easy to use.

In the present embodiment, the protective film forming film is preferably curable. Therefore, the protective film is preferably a cured product. Examples of the cured product include a heat-cured product and an energy ray-cured product. In the present embodiment, the protective film is more preferably a thermal cured product.

Whether or not the protective film forming film is thermosetting can be judged by the following method. First, a protective film forming film at normal temperature (23 ℃) is heated to a temperature higher than normal temperature, and then cooled to normal temperature, thereby producing a heated and cooled protective film forming film. Next, the hardness of the heated/cooled protective film forming film is compared with the hardness of the protective film forming film before heating at the same temperature, and when the heated/cooled protective film forming film is harder, the protective film forming film is judged to be thermosetting.

Further, the protective film forming film preferably has adhesiveness at normal temperature (23 ℃) or exhibits adhesiveness by heating. Thus, when a workpiece is superimposed on the protective film forming film, the workpiece and the protective film can be bonded to each other. Therefore, positioning can be ensured before curing the protective film forming film.

Next, a chip with a protective film, in which a protective film is formed on a chip as a workpiece, will be described.

As shown in fig. 4, the chip with a protective film 80 has a protective film 1 formed on the back surface side (upper side in fig. 4) of the chip 6a, and a convex electrode 6b formed on the front surface side (lower side in fig. 4) of the chip 6 a.

A circuit is formed on the front surface side of the chip 6a, and the convex electrode 6b is formed to be electrically connected to the circuit. Examples of the convex electrode 6b include a bump and a pillar electrode (pillar electrode).

In the present embodiment, the chip 80 with a protective film is disposed on the chip mounting substrate so that the surface on which the convex electrode 6b is formed faces the chip mounting substrate. Then, the protruding electrodes 6b are electrically and mechanically bonded to the substrate by a predetermined heat treatment (reflow treatment), and the chip 80 with the protective film is mounted on the substrate.

(1.3 composition for Forming protective film)

The protective film-forming composition is composed of a composition for forming a print through layer (print through layer composition) and a composition for forming a print recognition layer (print recognition layer composition). When the color difference between the print-through layer and the print-recognizing layer is within the above range, the components contained in the composition for a print-through layer and the components contained in the composition for a print-recognizing layer are not particularly limited.

For example, the composition of the print-through layer and the composition of the print recognition layer may be made different from each other, so that the thermal expansion coefficient of the print-through layer and the thermal expansion coefficient of the print recognition layer may be made different from each other. Thus, the warping of the workpiece can be controlled.

Further, the composition of the print through layer may be made close to the composition of the print recognition layer. This can reduce the risk of interlayer peeling due to a difference in interlayer thermal expansion and contraction in a heating step such as reflow soldering.

Hereinafter, the composition for the print penetration layer and the composition for the print recognition layer will be described.

(1.4 composition for printing penetrating layer)

In the present embodiment, the composition for a print penetrating layer is preferably a resin composition containing at least a polymer component (a), a curable component (B), and a filler (E). The polymer component can be considered as a component formed by a polymerization reaction of a polymerizable compound. The curable component is a component capable of undergoing a curing (polymerization) reaction. In the present invention, the polymerization reaction also includes a polycondensation reaction.

Further, components contained in the polymer component may be a curable component. In the present embodiment, when the composition for a print through layer contains such a component that belongs to both a polymer component and a curable component, the composition for a print through layer is considered to contain both a polymer component and a curable component.

(1.4.1 Polymer component)

The polymer component (a) provides the print-penetrating layer with film formability (film formability) and also provides the print-penetrating layer with appropriate tackiness (tack) to secure adhesion to the print recognition layer. The weight average molecular weight of the polymer component is usually in the range of 5 to 200 ten thousand, preferably in the range of 10 to 150 ten thousand, and particularly preferably in the range of 20 to 100 ten thousand. As such a polymer component, for example, an acrylic resin, a urethane resin, a phenoxy resin, a silicone resin, a saturated polyester resin, or the like can be used, and an acrylic resin is particularly preferably used.

In the present specification, unless otherwise specified, "weight average molecular weight" refers to a polystyrene equivalent value measured by a Gel Permeation Chromatography (GPC) method. The measurement based on this method is performed, for example, in the following manner: the high-speed chromatography column "TSK guard column H" was connected in sequence to a high-speed GPC apparatus "HLC-8120 GPC" manufactured by TOSOH CORPORATION _XL -H”、“TSK Gel GMH _XL ”、“TSK Gel G2000 H _XL "(all above, is TOSOH CORPORATION manufacturing), under the chromatographic column temperature of 40 ℃, the speed of feed liquid is 1.0 mL/min conditions, will show the refractometer as the detector.

Examples of the acrylic resin include (meth) acrylate copolymers composed of a (meth) acrylate monomer and a structural unit derived from a (meth) acrylic acid derivative. Among them, the (meth) acrylate monomer preferably includes an alkyl (meth) acrylate in which an alkyl group has 1 to 18 carbon atoms, and specifically includes methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and the like. Examples of the (meth) acrylic acid derivative include (meth) acrylic acid, glycidyl (meth) acrylate, hydroxyethyl (meth) acrylate, and the like.

In the present embodiment, glycidyl groups are preferably introduced into the acrylic resin using glycidyl methacrylate or the like. The acrylic resin having a glycidyl group introduced therein has an improved compatibility with an epoxy resin as a thermosetting component described later, and tends to easily obtain a print penetrating layer having stable performance. In this embodiment, it is preferable to introduce a hydroxyl group into an acrylic resin using hydroxyethyl acrylate or the like in order to control adhesiveness to a work or adhesive properties.

The glass transition temperature of the acrylic resin is preferably-70 ℃ to 40 ℃, 35 ℃ to 35 ℃, 20 ℃ to 30 ℃, 10 ℃ to 25 ℃ and 5 ℃ to 20 ℃. By setting the lower limit of the glass transition temperature of the acrylic resin to the above value, the viscosity of the print penetrating layer is easily reduced. By setting the upper limit of the glass transition temperature of the acrylic resin to the above value, the viscosity of the print penetrating layer is appropriately increased and the adhesion to the print recognizing layer is improved.

When the acrylic resin has m kinds (m is an integer of 2 or more) of structural units, the glass transition temperature of the acrylic resin can be calculated in the following manner. That is, when m monomers from which a structural unit in an acrylic resin is derived are each given a number that does not overlap from 1 to m in order and are named "monomer m", the glass transition temperature (Tg) of the acrylic resin can be calculated using the Fox equation shown below.

[ mathematical formula 1]

In the above formula, Tg is the glass transition temperature of the acrylic resin, m is an integer of 2 or more, Tgk is the glass transition temperature of a homopolymer of monomer m, and Wk is the mass fraction of structural unit m derived from monomer m in the acrylic resin, where Wk satisfies the following formula.

[ mathematical formula 2]

Wherein m and Wk are the same as those described above.

Tgk can be used in the form of a Polymer data Handbook, an adhesive Handbook, a Polymer Handbook or the like. For example, a homopolymer of methyl acrylate is Tgk deg.C, a homopolymer of n-butyl acrylate is Tgk deg.C-54 deg.C, a homopolymer of methyl methacrylate is Tgk deg.C, a homopolymer of 2-hydroxyethyl acrylate is Tgk deg.C-15 deg.C, a homopolymer of glycidyl methacrylate is Tgk deg.C 41 deg.C, and a homopolymer of 2-ethylhexyl acrylate is Tgk deg.C-70 deg.C.

The content of the polymer component is preferably 5 to 80 parts by mass, 8 to 70 parts by mass, 10 to 60 parts by mass, 12 to 55 parts by mass, 14 to 50 parts by mass, or 15 to 45 parts by mass, based on 100 parts by mass of the total weight of the composition for a print-penetrating layer. By setting the content of the polymer component within the above range, the viscosity of the print penetrating layer can be easily controlled.

(1.4.2 thermosetting Components)

The curable component (B) cures the print penetration layer to form a hard protective film. As the curable component, a thermosetting component, an energy ray curable component, or a mixture of these components can be used. When curing is performed by irradiation with an energy ray, the light transmittance of the print penetration layer decreases due to the inclusion of a filler, a colorant, and the like, which will be described later. Therefore, for example, when the thickness of the print penetration layer is large, the energy ray curing tends to be insufficient.

On the other hand, if the print-through layer has thermosetting properties, it can be sufficiently cured by heating even if its thickness is increased, and therefore a protective film having high protective performance can be formed. Further, the plurality of protective film forming films can be collectively heated by using a general heating tool such as a heating furnace, and the print-through layer can be thermally cured.

Therefore, in the present embodiment, it is desirable that the curable component be thermosetting. That is, the print-through layer is preferably thermosetting.

As the thermosetting component, for example, an epoxy resin, a thermosetting polyimide resin, an unsaturated polyester resin, and a mixture of these components are preferably used. The thermosetting polyimide resin is a generic name for a monomer or precursor polymer having a low molecular weight and a low viscosity, which forms a polyimide resin by heat curing. Non-limiting specific examples of thermosetting polyimide resins are described in, for example, japan society of fiber science "fiber and industry" ( society of recycling " task "), vol.50, No.3(1994), P106-P118.

Epoxy resins, which are thermosetting components, have the property of forming a three-dimensional network upon heating, thereby forming a strong coating film. As such an epoxy resin, various known epoxy resins can be used. In the present embodiment, the molecular weight (formula weight) of the epoxy resin is preferably 300 or more and less than 50000, 300 or more and less than 10000, 300 or more and less than 5000, 300 or more and less than 3000. In addition, the epoxy equivalent of the epoxy resin is preferably 50 to 5000g/eq, more preferably 100 to 2000g/eq, and further preferably 150 to 1000 g/eq.

Specific examples of such epoxy resins include glycidyl ethers of phenols such as bisphenol a, bisphenol F, resorcinol, phenyl novolac, and cresol novolac; glycidyl ethers of alcohols such as butanediol, polyethylene glycol, and polypropylene glycol; glycidyl ethers of carboxylic acids such as phthalic acid, isophthalic acid, and tetrahydrophthalic acid; glycidyl-type or alkyl glycidyl-type epoxy resins obtained by substituting active hydrogen bonded to a nitrogen atom such as aniline isocyanurate with a glycidyl group; such as vinylcyclohexene dioxide, 3, 4-epoxycyclohexylmethyl-3, 4-bicyclohexane carboxylate, 2- (3, 4-epoxy) cyclohexyl-5, 5-spiro (3, 4-epoxy) cyclohexane-m-dioxane, and so-called alicyclic epoxy compounds in which an epoxy group is introduced by, for example, oxidizing a carbon-carbon double bond in the molecule. In addition, epoxy resins having a biphenyl skeleton, a bicycloheadiene skeleton, a naphthalene skeleton, or the like can also be used.

When a thermosetting component is used as the curable component (B), it is preferable to use the curing agent (C) as an auxiliary at the same time. As the curing agent for epoxy resin, a heat-active latent epoxy resin curing agent is preferable. The "thermally active latent epoxy resin curing agent" refers to a type of curing agent that is not easily reacted with an epoxy resin at normal temperature (23 ℃) and is activated by heating to a certain temperature or higher to react with an epoxy resin. The activation method of the heat-active latent epoxy resin curing agent comprises the following steps: a method of generating active substances (anions, cations) by a chemical reaction based on heating; a method of stably dispersing in an epoxy resin at about normal temperature and causing a curing reaction by being compatible with and dissolved in the epoxy resin at high temperature; a method of using molecular sieve enclosed curing agent to elute at high temperature to initiate curing reaction; a method using a microcapsule, and the like.

Among the exemplified methods, a method of stably dispersing in an epoxy resin at about normal temperature and causing a curing reaction by being compatible and soluble with the epoxy resin at high temperature is preferable.

Specific examples of the heat-active latent epoxy resin curing agent include various onium salts, dibasic acid dihydrazide compounds, dicyanodiamide, amine adduct curing agents, high-melting-point active hydrogen compounds such as imidazole compounds, and the like. These thermally active latent epoxy resin curing agents may be used alone or in combination of two or more. In this embodiment, dicyanodiamine is particularly preferred.

Further, as a curing agent for the epoxy resin, a phenol resin is also preferable. As the phenol resin, a condensate of a phenol such as an alkylphenol, a polyphenol, or naphthol and an aldehyde can be used without particular limitation. Specifically, phenol novolac resin, o-cresol novolac resin, p-cresol novolac resin, t-butylphenol novolac resin, dicyclopentadiene cresol resin, poly-p-vinyl phenol resin, bisphenol a type novolac resin, or modified products thereof can be used.

The phenolic hydroxyl group contained in these phenolic resins is easily subjected to an addition reaction with the epoxy group of the epoxy resin by heating, and a cured product having high impact resistance can be formed.

The content of the curing agent (C) is preferably 0.01 to 30 parts by mass, 0.1 to 20 parts by mass, 0.2 to 15 parts by mass, or 0.3 to 10 parts by mass, based on 100 parts by mass of the epoxy resin. When the content of the curing agent (C) is within the above range, the network structure of the print-through layer becomes dense, and therefore the performance of protecting a workpiece as a protective film is easily obtained.

When dicyanodiamine is used as the curing agent (C), it is preferable to further use a curing accelerator (D) together. Preferred examples of the curing accelerator include imidazoles (imidazole in which one or more hydrogen atoms are substituted with a group other than a hydrogen atom), such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-dimethyloimidazole, 2-phenyl-4, 5-dimethyloimidazole and 2-phenyl-4-methyl-5-hydroxymethylimidazole. Among them, 2-phenyl-4, 5-dimethylol imidazole is particularly preferable.

The content of the curing accelerator is preferably 0.01 to 30 parts by mass, 0.1 to 20 parts by mass, 0.2 to 15 parts by mass, or 0.3 to 10 parts by mass, relative to 100 parts by mass of the epoxy resin. When the content of the curing accelerator (D) is within the above range, the network structure of the print through layer becomes dense, and therefore the performance of protecting a work as a protective film is easily obtained.

The total content of the thermosetting component and the curing agent is preferably 3 to 80 parts by mass, 5 to 60 parts by mass, 7 to 50 parts by mass, 9 to 40 parts by mass, or 10 to 30 parts by mass, based on 100 parts by mass of the total weight of the composition for a print-penetrating layer. When the thermosetting component and the curing agent are blended in such a ratio, an appropriate viscosity is exhibited before curing, and a stable bonding operation can be performed. Further, the property of protecting the workpiece as a protective film is easily obtained after curing.

(1.4.3 energy ray-curable component)

When the curable component (B) is an energy ray-curable component, the energy ray-curable component is preferably uncured, preferably has adhesiveness, and more preferably is uncured and has adhesiveness.

The energy ray-curable component is a component that is cured by irradiation with an energy ray, and is also a component for imparting film formability, flexibility, and the like to the protective film forming film and imparting protective properties to the cured protective film.

As the energy ray-curable component, for example, a compound having an energy ray-curable group is preferable. Examples of such a compound include a known compound having an energy ray-curable group, a compound obtained by adding an energy ray-curable component to an acrylic resin, and a mixture of an acrylic resin and a urethane acrylate.

(1.4.4 Filler)

By containing the filler (E) in the print-through layer, the thermal expansion coefficient of the cured product of the print-through layer can be easily adjusted. By making the thermal expansion coefficient of the cured product of the print through layer close to the thermal expansion coefficient of the workpiece, the adhesion reliability of the chip with the protective film obtained by forming a film using the protective film containing the print through layer is further improved. Further, by containing the filler (E) in the print through layer, a hard print through layer can be obtained, the moisture absorption rate of the print through layer can be further reduced, and the adhesion reliability of the chip with the protective film can be further improved.

The filler (E) may be either an organic filler or an inorganic filler, but is preferably an inorganic filler in view of shape stability at high temperatures.

Examples of preferable inorganic fillers include powders of silica, alumina, talc, calcium carbonate, 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, silica and surface-modified silica are preferable. The surface-modified silica is preferably surface-modified with a coupling agent, and more preferably surface-modified with a silane coupling agent.

The average particle size of the filler is preferably 0.02 to 10 μm, 0.05 to 5 μm, or 0.05 to 3 μm.

By setting the range of the average particle size of the filler within the above range, the handling of printing through the layer-forming composition becomes easy, and the protective film-forming film becomes easy to be smoothed. As a result, the composition for a print through layer and the quality of the print through layer can be easily stabilized.

In the present specification, unless otherwise specified, "average particle diameter" refers to the value of the particle diameter (D50) when the integrated value in the particle size distribution curve obtained by the laser diffraction scattering method is 50%.

The content of the filler is preferably 15 to 80 parts by mass, 30 to 75 parts by mass, 40 to 70 parts by mass, or 45 to 65 parts by mass, based on 100 parts by mass of the total weight of the composition for a print-penetrating layer.

By setting the lower limit of the content of the filler to the above value, the viscosity of the print penetrating layer can be easily reduced. By setting the upper limit of the content of the filler to the above value, the adhesive strength between the print-through layer and the print recognition layer is appropriately improved.

(1.4.5 coupling agent)

The printing-through layer preferably contains a coupling agent (F). By containing the coupling agent, the adhesiveness between the print-through layer and the print recognition layer can be improved without impairing the heat resistance of the protective film after curing the print-through layer, and the water resistance (moist heat resistance) can also be improved. As the coupling agent, a silane coupling agent is preferable from the viewpoint of its versatility and cost advantage.

Examples of the silane coupling agent include gamma-glycidyloxypropyltrimethoxysilane, gamma-glycidyloxypropylmethyldiethoxysilane, beta- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, gamma- (methacryloyloxypropyl) trimethoxysilane, gamma-aminopropyltrimethoxysilane, N-6- (aminoethyl) -gamma-aminopropylmethyldiethoxysilane, N-phenyl-gamma-aminopropyltrimethoxysilane, gamma-ureidopropyltriethoxysilane, gamma-mercaptopropyltrimethoxysilane, gamma-mercaptopropylmethyldimethoxysilane, bis (3-triethoxysilylpropyl) tetrasulfide, gamma-glycidyloxypropyltrimethoxysilane, gamma-glycidyloxypropylmethyldimethoxysilane, gamma-glycidyloxypropyltrimethoxysilane, gamma-glycidyloxypropylmethyldimethoxysilane, gamma-glycidyloxypropyltrimethoxysilane, gamma-glycidyloxypropylmethyldimethoxysilane, gamma-hydroxysilane, gamma-glycidyloxypropyltetrasulfide, gamma-glycidyloxypropyltrimethoxysilane, gamma-hydroxysilane-tetrasulfide, Methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, imidazolosilane, and the like. These silane coupling agents may be used alone or in combination of two or more.

The content of the coupling agent is preferably 0.01 to 20 parts by mass, 0.1 to 10 parts by mass, 0.2 to 5 parts by mass, or 0.3 to 3 parts by mass, based on 100 parts by mass of the total weight of the composition for a printing through layer.

(1.4.6 colorant)

The printing-through layer preferably contains a colorant (G). Accordingly, since the rear surface of the workpiece such as a chip is covered, infrared rays or electromagnetic waves can be shielded, and failures of the workpiece such as a chip can be reduced.

Examples of the colorant (G) include a black colorant, a white colorant, a cyan (cyan) colorant, a magenta colorant, and a yellow colorant. These colorants are composed of, for example, organic pigments, organic dyes, inorganic pigments, and the like.

Examples of the black coloring agent include carbon black (furnace black, channel black, acetylene black, thermal cracking black, lamp black, etc.), graphite (black lead), copper oxide, manganese dioxide, aniline black, perylene black, titanium black, cyanine black, activated carbon, ferrite (nonmagnetic ferrite, magnetic ferrite, etc.), magnetite, chromium oxide, iron oxide, molybdenum disulfide, chromium complexes, complex oxide-based black pigments, anthraquinone-based organic black pigments, black dyes, black pigments, and the like.

Examples of the black dye include c.i. solvent black 3, c.i. solvent black 7, c.i. solvent black 22, c.i. solvent black 27, c.i. solvent black 29, c.i. solvent black 34, c.i. solvent black 43, and c.i. solvent black 70; c.i. direct black 17, c.i. direct black 19, c.i. direct black 22, c.i. direct black 32, c.i. direct black 38, c.i. direct black 51, c.i. direct black 71; c.i. acid black 1, c.i. acid black 2, c.i. acid black 24, c.i. acid black 26, c.i. acid black 31, c.i. acid black 48, c.i. acid black 52, c.i. acid black 107, c.i. acid black 109, c.i. acid black 110, c.i. acid black 119, c.i. acid black 154; c.i. disperse black 1, c.i. disperse black 3, c.i. disperse black 10, c.i. disperse black 24, and the like.

Examples of the black pigment include c.i. pigment black 1 and c.i. pigment black 7.

As the black colorant, carbon black is preferable.

Examples of the white colorant include inorganic white colorants such as titanium oxide (titanium dioxide such as rutile type titanium dioxide and anatase type titanium dioxide), zinc oxide, aluminum oxide, silicon oxide, zirconium oxide, magnesium oxide, calcium oxide, tin oxide, barium oxide, cesium oxide, yttrium oxide, magnesium carbonate, calcium carbonate (light calcium carbonate, heavy calcium carbonate, etc.), barium carbonate, zinc carbonate, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, aluminum silicate, magnesium silicate, calcium silicate, barium sulfate, calcium sulfate, barium stearate, zinc oxide, zinc sulfide, talc, silica, alumina, clay, kaolin, titanium phosphate, mica, gypsum, white carbon, diatomaceous earth, bentonite, lithopone, zeolite, sericite, and halloysite.

Examples of the coloring agent include organic white coloring agents such as acrylic resin particles, polystyrene resin particles, polyurethane resin particles, amide resin particles, polycarbonate resin particles, silicone resin particles, urea-formalin resin particles, and melamine resin particles. Further, as the white colorant, a fluorescent whitening agent may also be used.

Examples of the cyan colorant include c.i. solvent blue 25, c.i. solvent blue 36, c.i. solvent blue 60, c.i. solvent blue 70, c.i. solvent blue 93, and c.i. solvent blue 95; cyan dyes such as c.i. acid blue 6 and c.i. acid blue 45.

Further, c.i. pigment blue 1, c.i. pigment blue 2, c.i. pigment blue 3, c.i. pigment blue 15:1, c.i. pigment blue 15:2, c.i. pigment blue 15:3, c.i. pigment blue 15:4, c.i. pigment blue 15:5, c.i. pigment blue 15:6, c.i. pigment blue 16, c.i. pigment blue 17:1, c.i. pigment blue 18, c.i. pigment blue 22, c.i. pigment blue 25, c.i. pigment blue 56, c.i. pigment blue 60, c.i. pigment blue 63, c.i. pigment blue 65, c.i. pigment blue 66; c.i. vat blue 4, c.i. vat blue 60; and cyan pigments such as c.i. pigment green 7.

Examples of the magenta colorant include c.i. solvent red 1, c.i. solvent red 3, c.i. solvent red 8, c.i. solvent red 23, c.i. solvent red 24, c.i. solvent red 25, c.i. solvent red 27, c.i. solvent red 30, c.i. solvent red 49, c.i. solvent red 52, c.i. solvent red 58, c.i. solvent red 63, c.i. solvent red 81, c.i. solvent red 82, c.i. solvent red 83, c.i. solvent red 84, c.i. solvent red 100, c.i. solvent red 109, c.i. solvent red 111, c.i. solvent red 121, and c.i. solvent red 122; c.i. disperse red 9; c.i. solvent violet 8, c.i. solvent violet 13, c.i. solvent violet 14, c.i. solvent violet 21, c.i. solvent violet 27; c.i. disperse violet 1; c.i. basic red 1, c.i. basic red 2, c.i. basic red 9, c.i. basic red 12, c.i. basic red 13, c.i. basic red 14, c.i. basic red 15, c.i. basic red 17, c.i. basic red 18, c.i. basic red 22, c.i. basic red 23, c.i. basic red 24, c.i. basic red 27, c.i. basic red 29, c.i. basic red 32, c.i. basic red 34, c.i. basic red 35, c.i. basic red 36, c.i. basic red 37, c.i. basic red 38, c.i. basic red 39, c.i. basic red 40; magenta dyes such as c.i. basic violet 1, c.i. basic violet 3, c.i. basic violet 7, c.i. basic violet 10, c.i. basic violet 14, c.i. basic violet 15, c.i. basic violet 21, c.i. basic violet 25, c.i. basic violet 26, c.i. basic violet 27, and c.i. basic violet 28.

Examples of the pigment include c.i. pigment red 1, c.i. pigment red 2, c.i. pigment red 3, c.i. pigment red 4, c.i. pigment red 5, c.i. pigment red 6, c.i. pigment red 7, c.i. pigment red 8, c.i. pigment red 9, c.i. pigment red 10, c.i. pigment red 11, c.i. pigment red 12, c.i. pigment red 13, c.i. pigment red 14, c.i. pigment red 15, c.i. pigment red 16, c.i. pigment red 17, c.i. pigment red 18, c.i. pigment red 19, c.i. pigment red 21, c.i. pigment red 22, c.i. pigment red 23, c.i. pigment red 30, c.i. pigment red 31, c.i. pigment red 32, c.i. pigment red 37, c.i. pigment red 38, c.i. pigment red 48, c.i. pigment red 49, c.i. pigment red 48, c.i. pigment red 42, c.i. pigment red 48, c.i. pigment red 49, c.i. pigment red 48, c.i. pigment red 49, c.i. pigment red 48, c.i. pigment red 4, c.i. pigment red 48, c.i. pigment red 1, c.i. pigment red 48, c.i. pigment red 6, c.i. pigment red 48, c.i. pigment red 4, c.i. pigment red 6, c.i. pigment red 4, c.i. pigment red 5, c.i. pigment red 6, c.i. pigment red 5, c.i. pigment red 48, c.i. pigment red 5, c.i. pigment red 49, c.i. pigment red 5, c.i. pigment red 49, c.i. pigment red 5, c.i. pigment red 49, c.i., C.i. pigment red 52:2, c.i. pigment red 53:1, c.i. pigment red 54, c.i. pigment red 55, c.i. pigment red 56, c.i. pigment red 57:1, c.i. pigment red 58, c.i. pigment red 60:1, c.i. pigment red 63:1, c.i. pigment red 63:2, c.i. pigment red 64:1, c.i. pigment red 67, c.i. pigment red 68, c.i. pigment red 81, c.i. pigment red 83, c.i. pigment red 87, c.i. pigment red 88, c.i. pigment red 89, c.i. pigment red 90, c.i. pigment red 92, c.i. pigment red 101, c.i. pigment red 104, c.i. pigment red 105, c.i. pigment red 108, c.i. pigment red 163, c.i. pigment red 123, c.i. pigment red 152, c.i. pigment red 123, c.i. pigment red 114, c.i. pigment red 123, c.i. pigment red 152, c.i. pigment red 108, c.i. pigment red 123, c.i. pigment red 150, c.i. pigment red 108, c.i. pigment red 123, c.i. pigment red 60, c.i. pigment red 123, c.i. pigment red 60, c.i. pigment red 150, c.i. pigment red 60, c.i. pigment red 81, c.i. pigment red 152, c.i. pigment red 150, c.i. pigment red 108, c.i. pigment red 152, c.i. pigment red 108, c.i. pigment red 152, c.i. pigment red 108, c.i. pigment red 152, c.i. pigment red 108, c, C.i. pigment red 168, c.i. pigment red 170, c.i. pigment red 171, c.i. pigment red 172, c.i. pigment red 175, c.i. pigment red 176, c.i. pigment red 177, c.i. pigment red 178, c.i. pigment red 179, c.i. pigment red 184, c.i. pigment red 185, c.i. pigment red 187, c.i. pigment red 190, c.i. pigment red 193, c.i. pigment red 202, c.i. pigment red 206, c.i. pigment red 207, c.i. pigment red 209, c.i. pigment red 219, c.i. pigment red 222, c.i. pigment red 224, c.i. pigment red 238, c.i. pigment red 245; c.i. pigment violet 3, c.i. pigment violet 9, c.i. pigment violet 19, c.i. pigment violet 23, c.i. pigment violet 31, c.i. pigment violet 32, c.i. pigment violet 33, c.i. pigment violet 36, c.i. pigment violet 38, c.i. pigment violet 43, c.i. pigment violet 50; magenta pigments such as c.i. vat red 1, c.i. vat red 2, c.i. vat red 10, c.i. vat red 13, c.i. vat red 15, c.i. vat red 23, c.i. vat red 29 and c.i. vat red 35.

Examples of the yellow colorant include yellow dyes such as c.i. solvent yellow 19, c.i. solvent yellow 44, c.i. solvent yellow 77, c.i. solvent yellow 79, c.i. solvent yellow 81, c.i. solvent yellow 82, c.i. solvent yellow 93, c.i. solvent yellow 98, c.i. solvent yellow 103, c.i. solvent yellow 104, c.i. solvent yellow 112, and c.i. solvent yellow 162.

Examples of the pigment include c.i. pigment orange 31, c.i. pigment orange 43; c.i. pigment yellow 1, c.i. pigment yellow 2, c.i. pigment yellow 3, c.i. pigment yellow 4, c.i. pigment yellow 5, c.i. pigment yellow 6, c.i. pigment yellow 7, c.i. pigment yellow 10, c.i. pigment yellow 11, c.i. pigment yellow 12, c.i. pigment yellow 13, c.i. pigment yellow 14, c.i. pigment yellow 15, c.i. pigment yellow 16, c.i. pigment yellow 17, c.i. pigment yellow 23, c.i. pigment yellow 24, c.i. pigment yellow 34, c.i. pigment yellow 35, c.i. pigment yellow 37, c.i. pigment yellow 42, c.i. pigment yellow 53, c.i. pigment yellow 55, c.i. pigment yellow 65, c.i. pigment yellow 73, c.i. pigment yellow 74, c.i. pigment yellow 75, c.i. pigment yellow 81, c.i. pigment yellow 100, c.i. pigment yellow 101, c.i. pigment yellow 100, c.i. pigment yellow 108, c.i. pigment yellow 95, c.i. pigment yellow 100, c.i. pigment yellow 95, c.i. pigment yellow 100, c.i. pigment yellow 95, c.i. pigment yellow 100, c.i. pigment yellow 95, c, C.i. pigment yellow 117, c.i. pigment yellow 120, c.i. pigment yellow 128, c.i. pigment yellow 129, c.i. pigment yellow 133, c.i. pigment yellow 138, c.i. pigment yellow 139, c.i. pigment yellow 147, c.i. pigment yellow 150, c.i. pigment yellow 151, c.i. pigment yellow 153, c.i. pigment yellow 154, c.i. pigment yellow 155, c.i. pigment yellow 156, c.i. pigment yellow 167, c.i. pigment yellow 172, c.i. pigment yellow 173, c.i. pigment yellow 180, c.i. pigment yellow 185, c.i. pigment yellow 195; yellow pigments such as c.i. vat yellow 1, c.i. vat yellow 3 and c.i. vat yellow 20.

In order to obtain a desired color, it is only necessary to select the colorant appropriately. One kind of the colorant may be used, or two or more kinds of the colorants may be used in combination. In the present embodiment, as described above, the print-through layer is preferably black or gray, and therefore, the colorant may be selected so as to be black or gray.

The content of the colorant is preferably 0.01 to 30 parts by mass, 0.02 to 20 parts by mass, or 0.03 to 10 parts by mass, based on 100 parts by mass of the total weight of the composition for a print-penetrating layer.

The average particle size of the colorant is preferably 1 to 500nm, 3 to 100nm, 5 to 50 nm. If the average particle diameter of the colorant is within the above range, the light transmittance can be easily controlled within a desired range.

(1.4.7 crosslinking agent)

The printing through layer preferably contains a crosslinking agent (H). When the composition for a print-through layer contains an acrylic copolymer containing a structural unit derived from a functional group-containing monomer as the polymer component (a), a crosslinking agent (H) may be further contained.

The crosslinking agent is contained to cause a crosslinking reaction with the functional group of the acrylic copolymer to form a network structure, whereby the cohesive strength and adhesive strength of the obtained film for forming a protective film can be improved.

Examples of the crosslinking agent (H) include an organic polyisocyanate compound and an organic polyimine compound.

Examples of the organic polyisocyanate compound include an aromatic polyisocyanate compound, an aliphatic polyisocyanate compound, an alicyclic polyisocyanate compound, a trimer of these organic polyisocyanate compounds, and an isocyanate-terminated urethane prepolymer obtained by reacting these organic polyisocyanate compounds with a polyol compound.

Examples of the organic polyisocyanate compound include 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, 1, 3-xylylene diisocyanate, 1, 4-xylylene diisocyanate, diphenylmethane-4, 4 '-diisocyanate, diphenylmethane-2, 4' -diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4, 4 '-diisocyanate, dicyclohexylmethane-2, 4' -diisocyanate, lysine isocyanate, and polyol adducts of these organic polyisocyanates.

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.

The content of the crosslinking agent (H) is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and still more preferably 0.5 to 5 parts by mass, based on 100 parts by mass of the polymer component (A).

(1.4.8 other additives)

The composition for a print-through layer may contain, as other additives, for example, a photopolymerization initiator, a crosslinking agent, a plasticizer, an antistatic agent, an antioxidant, a gettering agent, a thickener, a releasing agent, and the like, within a range not to impair the effects of the present invention.

(1.5 printing identification layer composition)

In the present embodiment, the composition for a print recognition layer is preferably a resin composition containing at least a polymer component (a), a curable component (B), and a filler (E), as in the composition for a print through layer.

As the polymer component (a), the curable component (B), the curing agent (C), the curing accelerator (D), the filler (E), the coupling agent (F), and the crosslinking agent (H), the components described in the composition for a print through layer can be used.

Among these, since the print recognition layer is attached to the back surface of the wafer, it is preferable to contain a component that increases the adhesive force to the back surface of the wafer in a predetermined amount. Examples of such components include a coupling agent for improving adhesion to the wafer, and a filler for adjusting a thermal expansion coefficient.

The colorant (G) may be appropriately selected so that the color difference between the print-penetrating layer and the print-recognizing layer is within the above range. For example, when the through-print layer is black or gray, white colorants, cyan colorants, magenta colorants, yellow colorants, and the like having a large color difference from black or gray are preferable, and white colorants and yellow colorants are particularly preferable.

Further, other additives are the same as those in the composition for a print through layer.

(2. sheet for Forming protective film)

The protective film forming sheet of the present embodiment includes the above-described protective film forming film and a release film disposed on at least one main surface of the protective film forming film. The release film is peeled off when the film is formed using the protective film.

The protective film forming sheet 61 shown in fig. 5A has a structure in which a first release film 21 for supporting the protective film forming film 10 is disposed on one main surface 10a of the protective film forming film 10, and a second release film 22 is disposed on the other main surface 10 b.

On the other hand, the protective film forming sheet 62 shown in fig. 5B has a structure in which the first release film 21 supporting the protective film forming film 10 is disposed on one main surface 10a of the protective film forming film 10, and the release film is not disposed on the other main surface 10B.

The protective film-forming sheet of the present embodiment is used for forming a protective film on a workpiece or a workpiece by attaching a protective film-forming film to the workpiece and forming the protective film-forming film into a protective film when the workpiece is machined.

(2.1 Release film)

The release film is a film capable of supporting the protective film forming film in a releasable manner. The release film may be composed of one layer (single layer) or two or more layers of the base material, and the surface of the base material may be subjected to a release treatment from the viewpoint of controlling releasability. That is, the surface of the substrate may be modified, or a material not derived from the substrate (release agent layer) may be formed on the surface of the substrate.

The base material is not particularly limited as long as it can support the protective film forming film until the protective film forming film is attached to the workpiece, and is generally composed of a film (hereinafter referred to as "resin film") mainly made of a resin material.

As specific examples of the resin film, a polyethylene film, a polypropylene film, a polybutylene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, a polyethylene terephthalate film, a polyethylene naphthalate film, a polybutylene terephthalate film, a polyurethane film, an ethylene vinyl acetate copolymer film, an ionomer resin film, an ethylene- (meth) acrylic acid copolymer film, an ethylene- (meth) acrylate copolymer film, a polystyrene film, a polycarbonate film, a polyimide film, a fluororesin film, and the like can be used. In addition, crosslinked films of these films may also be used. Further, a laminated film of these films is also possible. In the present embodiment, a polyethylene terephthalate film is preferable from the viewpoint of environmental safety, cost, and the like.

The resin film may contain various additives such as a colorant, a flame retardant, a plasticizer, an antistatic agent, a lubricant, and a filler.

The release agent layer can be obtained by applying a coating agent containing the composition for a release agent layer on one surface of a base material, and then drying and curing the coating film. The composition for a release agent layer is not particularly limited as long as it can impart releasability between the substrate and the protective film-forming film. In the present embodiment, the composition for a release agent layer is preferably, for example, an alkyd type release agent, a silicone type release agent, a fluorine type release agent, an unsaturated polyester type release agent, a polyolefin type release agent, or a paraffin type release agent, and among them, a silicone type release agent is preferable.

The thickness of the release film is not particularly limited, but is preferably 30 to 100. mu.m, more preferably 40 to 80 μm, and still more preferably 45 to 70 μm.

In the case where the release films are formed on both main surfaces of the protective film forming film, it is preferable to increase the peeling force of one release film to make it a heavy release type release film and decrease the peeling force of the other release film to make it a light release type release film.

(3. composite sheet for Forming protective film)

The composite sheet for forming a protective film of the present embodiment has the above-described protective film forming film and a support sheet for supporting the protective film forming film.

The composite sheet 71 for forming a protective film shown in fig. 6A has the following configuration, that is, includes: an adhesive sheet 4 in which an adhesive layer 42 is laminated on one surface of a substrate 41, a protective film forming film 10 laminated on the adhesive layer 42 side of the adhesive sheet 4, and a jig adhesive layer 5 laminated on the peripheral portion of the protective film forming film 10 on the side opposite to the adhesive sheet 4. The adhesive layer 5 for a jig is a layer for adhering the composite sheet 71 for forming a protective film to a jig such as a ring frame. Thus, the adhesive sheet is a support sheet.

The composite sheet 72 for forming a protective film shown in fig. 6B has the following configuration: an adhesive sheet 4 in which an adhesive layer 42 is laminated on one surface of a substrate 41, and a protective film forming film 10 laminated on the adhesive layer 42 side of the adhesive sheet 4.

The composite sheet for forming a protective film of the present embodiment is used for attaching to a workpiece to hold the workpiece and forming a protective film on the workpiece or a workpiece by forming the protective film forming film into the protective film at the time of processing the workpiece.

Specifically, it is used to hold a wafer when the wafer as a workpiece is diced and form a protective film on a chip as a processed product obtained by the dicing, but is not limited thereto.

(3.1 adhesive sheet)

The adhesive sheet 4 of the composite sheet for forming a protective film of the present embodiment is configured to include a substrate 41 and an adhesive layer 42 laminated on one surface of the substrate 41.

(3.1.1. base material)

The material of the adhesive sheet 4 is not particularly limited as long as the substrate 41 is suitable for processing a workpiece, for example, for dicing and expanding a wafer, and is generally composed of a film (hereinafter referred to as a "resin film") mainly composed of a resin material.

Specific examples of the resin film include polyethylene films such as Low Density Polyethylene (LDPE) films, Linear Low Density Polyethylene (LLDPE) films, and High Density Polyethylene (HDPE) films, polyolefin films such as polypropylene films, polybutene films, polybutadiene films, polymethylpentene films, ethylene-norbornene copolymer films, and norbornene resin films; ethylene copolymer films such as ethylene-vinyl acetate copolymer films, ethylene- (meth) acrylic acid copolymer films, and ethylene- (meth) acrylic acid ester copolymer films; polyvinyl chloride films such as polyvinyl chloride films and vinyl chloride copolymer films; polyester-based films such as polyethylene terephthalate films and polybutylene terephthalate films; a polyurethane film; a polyimide film; a polystyrene film; a polycarbonate film; fluororesin films, and the like. Further, a modified film such as a crosslinked film or an ionomer film of these films can also be used. The substrate 41 may be a film composed of one of these films, or may be a laminated film obtained by combining two or more of these films, and polypropylene is preferable from the viewpoint of heat resistance.

For the purpose of improving the adhesion between the resin film and the adhesive layer 42 laminated on the surface of the resin film, one surface or both surfaces of the resin film may be subjected to surface treatment by an oxidation method, an embossing method, or the like, or undercoating treatment, as necessary. Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromium oxidation treatment (wet type), flame treatment, hot air treatment, ozone-ultraviolet irradiation treatment, and the like, and examples of the roughening method include sandblasting, thermal spraying, and the like.

The resin film may further contain various additives such as a colorant, a flame retardant, a plasticizer, an antistatic agent, a lubricant, and a filler.

The thickness of the substrate 41 is not particularly limited as long as the composite sheet for forming a protective film can function properly in each step. The thickness of the substrate 41 is preferably in the range of 20 to 450 μm, more preferably in the range of 25 to 400 μm, and particularly preferably in the range of 50 to 350 μm.

(3.1.2. adhesive layer)

The adhesive layer 42 included in the adhesive sheet 4 of the composite sheet for forming a protective film of the present embodiment may be composed of a non-energy ray-curable adhesive or an energy ray-curable adhesive. The non-energy ray-curable adhesive is preferably one having a desired adhesive force and removability, and examples thereof include acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, and polyvinyl ether adhesives. Among them, an acrylic adhesive having high adhesion to the protective film forming film 10 and capable of effectively suppressing the falling off of the work or the work processed product in the dicing step or the like is preferable. An acrylic adhesive is also preferable from the viewpoint of easy control of the pick-up suitability of the work piece with the protective film.

On the other hand, since the adhesive force of the energy ray-curable adhesive is reduced by the irradiation of the energy ray, when the work or the work-piece is separated from the adhesive sheet 4, the work or the work-piece can be easily separated by the irradiation of the energy ray.

The energy ray-curable adhesive constituting the adhesive layer 42 may contain a polymer having energy ray-curability as a main component, or a mixture of a polymer having no energy ray-curability and an energy ray-curable monomer and/or oligomer as a main component.

Examples of the polymer having energy ray curability include (meth) acrylate (co) polymers having an energy ray curable group introduced thereto. Examples of the energy ray-curable monomer and/or oligomer include esters of a polyol and (meth) acrylic acid. The energy ray-curable adhesive may contain an additive such as a photopolymerization initiator or a crosslinking agent in addition to the energy ray-curable component.

The thickness of the adhesive agent layer 42 is not particularly limited as long as the composite sheet for forming a protective film can function properly in each step. Specifically, the thickness of the adhesive layer is preferably 1 to 50 μm, 2 to 30 μm, 2 to 20 μm, 3 to 10 μm, or 3 to 8 μm.

As the adhesive constituting the adhesive layer for a jig, adhesives having desired adhesive force and removability are preferable, and for example, acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, polyvinyl ether adhesives, and the like can be used. Among these, an acrylic adhesive having high adhesion to a jig such as a ring frame and capable of effectively suppressing peeling of the composite sheet for forming a protective film from the ring frame or the like in a dicing step or the like is preferable. In addition, a base material as a core material may be interposed in the thickness direction of the adhesive agent layer for a jig.

The thickness of the adhesive layer 5 for a jig is preferably 5 to 200 μm, and particularly preferably 10 to 100 μm from the viewpoint of adhesiveness to a jig such as a ring frame.

(4. method for producing protective film-forming film and protective film-forming sheet)

The method for producing the protective film-forming film is not particularly limited. The film can be produced using the composition for a print-through layer and the composition for a print-recognition layer described above, or using a composition (coating agent) obtained by diluting the composition for a print-through layer and the composition for a print-recognition layer with a solvent. The coating agent can be prepared by mixing the components constituting the composition for a print through layer and the composition for a print recognition layer by a known method.

The coating agent of the obtained composition for a through-print layer is applied to the release surface of the first release film using a coater such as a roll coater, a knife coater, a roll coater, an air knife coater, a die coater, a bar coater, a gravure coater, or a curtain coater, and dried, thereby forming a through-print layer on the first release film.

Next, the coating agent of the obtained print recognition layer composition is applied to the release surface of the second release film by using a coater such as a roll coater, a knife coater, a roll coater, an air knife coater, a die coater, a bar coater, a gravure coater, or a curtain coater, and dried, thereby forming a print recognition layer on the second release film.

Further, the protective film-forming sheet shown in fig. 5A can be obtained by bonding the exposed surface of the print recognition layer formed on the second release film to the exposed surface of the print through layer formed on the first release film.

(5. method for producing composite sheet for Forming protective film)

The method for producing the composite sheet for forming a protective film is not particularly limited. For example, it can be produced by: after a first laminate including a protective film forming film and a second laminate including an adhesive sheet as a supporting sheet are separately prepared, the protective film forming film and the adhesive sheet are laminated using the first laminate and the second laminate.

The first laminate can be produced by the same method as that for the protective film-forming sheet described above. That is, the exposed surface of the print through layer on the first release film and the exposed surface of the print recognition layer on the second release film are laminated.

On the other hand, in order to produce the second laminate, first, an adhesive composition constituting the adhesive layer or a composition (coating agent) obtained by diluting the adhesive composition with a solvent is prepared. Next, a coating agent is applied to the release surface of the third release film and dried, thereby forming an adhesive layer on the third release film. Then, a substrate was bonded to the exposed surface of the adhesive layer to obtain a laminate (second laminate) composed of an adhesive sheet composed of the substrate and the adhesive layer and a third release film.

When the adhesive layer is made of an energy ray-curable adhesive, the adhesive layer may be cured by irradiating the adhesive layer with an energy ray at this stage, or the adhesive layer may be cured after lamination with a protective film-forming film. In addition, when the adhesive layer is cured after being laminated with the protective film-forming film, the adhesive layer may be cured before the dicing step or may be cured after the dicing step.

As the energy ray, ultraviolet rays, electron beams, or the like are generally used. The dose of the energy ray varies depending on the kind of the energy ray, and when ultraviolet rays are used, for example, it is preferable that the dose is 50 to 1000mJ/cm in terms of light quantity ² Particularly preferably 100 to 500mJ/cm ² . In addition, when an electron beam is used, it is preferably about 10 to 1000 krad.

After the first laminate and the second laminate are obtained in the above manner, the second release film of the first laminate is peeled off, and the third release film of the second laminate is peeled off, so that the protective film forming film exposed in the first laminate and the adhesive layer of the adhesive sheet exposed in the second laminate are bonded.

In this way, a composite sheet for forming a protective film is obtained, which comprises an adhesive sheet obtained by laminating an adhesive layer on a substrate, a protective film forming film laminated on the adhesive layer side of the adhesive sheet, and a first release film laminated on the protective film forming film on the side opposite to the adhesive sheet. If necessary, after the first release film is peeled off, a jig adhesive layer is formed on the periphery of the exposed protective film forming film or adhesive layer.

(6. method for manufacturing device)

As an example of a method for manufacturing a device using the protective film forming film of the present embodiment, a method for manufacturing a mounting substrate on which a chip with a protective film obtained by processing a wafer to which the protective film forming film is attached is mounted will be described.

The method for manufacturing the device of the present embodiment includes at least the following steps 1 to 6.

Step 1: a step of attaching a protective film forming film provided in the protective film forming sheet or a protective film forming film provided in the protective film forming composite sheet to the back surface of the wafer;

and a step 2: forming the attached protective film into a protective film;

step 3: a step of performing laser printing on the protective film or the protective film forming film;

and step 4: singulating the wafer having the protective film or the protective film forming film on the back surface thereof into individual pieces to obtain a plurality of chips each having the protective film or the protective film forming film;

step 5: disposing a chip having a protective film or a protective film forming film on a substrate;

step 6: and heating the chip with the protective film or the protective film forming film disposed on the substrate and the substrate.

As is clear from the above, step 2 may be performed after step 3, step 4, or step 5, or may be performed simultaneously with step 6.

A method for manufacturing the device having the steps 1 to 6 will be described with reference to fig. 7 to 9.

As shown in fig. 7, the protective film forming film 10 of the composite sheet 71 for forming a protective film is attached to the wafer 6 (step 1). Since the adhesive agent layer 5 for a jig is provided on the outer periphery of the protective film forming film 10, the adhesive agent layer 5 for a jig is attached to the ring frame 7. The wafer 6 is attached to the surface of the protective film forming film 10 opposite to the surface to which the adhesive layer 42 is attached. When the protective film forming film 10 is attached to the wafer 6, the protective film forming film 10 may be heated to exhibit adhesiveness as necessary.

Then, the attached protective film forming film 10 is formed into a protective film to form a protective film (step 2), and the wafer 6 with the protective film is obtained. When the protective film forming film 10 is thermosetting, the protective film forming film 10 only needs to be heated at a prescribed temperature for an appropriate time. When the protective film forming film 10 is energy ray-curable, energy rays may be incident from the adhesive sheet 4 or the release film side.

The curing of the protective film forming film 10 may be performed after the dicing step, or the protective film forming film may be cured after the chip with the protective film forming film is picked up from the adhesive sheet, but it is preferable to perform the curing of the protective film forming film 10 before the dicing step.

Next, laser printing is performed on the protective film or the protective film forming film (step 4). Step 4 is performed after step 3. In the present embodiment, the step 4 is preferably performed before the step 5.

In the laser printing, as described above, the laser beam is completely removed from the print-through layer and the print-through layer is penetrated to perform marking. By such laser printing, the print recognition layer is exposed to the outside in a printed shape. Since the color difference between the print-penetrating layer and the print-recognizing layer is within the above range, even if the print formed by the print-recognizing layer is extremely fine, it can be recognized sufficiently. Laser printing may be performed using a known laser printing apparatus.

Next, as shown in fig. 8, the wafer 6 with the protective film is diced by a known method to obtain chips (chips 80 with a protective film) having the protective film 1 shown in fig. 4 (step 3).

Then, the dicing sheet or the adhesive sheet is spread in the planar direction as needed, and the chip with the protective film can be picked up from the dicing sheet or the adhesive sheet by an adsorption chuck or the like.

The picked-up chip with the protective film may be transported to a subsequent step, or may be temporarily stored in a tray, a tape, or the like and transported to a subsequent step after a predetermined time.

As shown in fig. 9, the chip 80 with the protective film transferred to the subsequent step is transferred to the substrate 50 by the suction chuck C, and the chip 80 with the protective film is detached from the suction chuck C at the terminal portion on the substrate and is disposed at a position where the connection electrode such as the bump can be connected to the terminal portion such as the connection pad (step 5).

The chip with the protective film disposed at a predetermined position on the substrate is subjected to a heat treatment (reflow treatment) (step 6). The reflow treatment is preferably carried out at a maximum heating temperature of 180 to 350 ℃ for a reflow time of 2 to 10 minutes, for example.

In the reflow process, the protruding electrodes 6b of the chip 80 with the protective film are melted and electrically and mechanically joined to the terminal portions on the substrate, and the chip 80 with the protective film is mounted on the substrate.

(7. modification)

In the above-described embodiment, the composite sheet for forming a protective film in which the protective film forming film is integrated with the support sheet has been described, but the support sheet may not be integrated with the entire protective film forming film. That is, the present invention also includes a kit of a protective film-forming composite sheet comprising the print recognition layer for attachment to a workpiece and a laminate having a support sheet and a print-penetrating layer formed on the support sheet for attachment to the print recognition layer. The kit can be used in the following manner: first, the print recognition layer is attached to the back surface of the wafer, and then the print through layer formed on the support sheet is attached to the print recognition layer.

Examples

The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples.

(preparation of sample for color difference evaluation)

The following components were mixed at the ratios shown in table 1 (in terms of solid content), and diluted with methyl ethyl ketone to a solid content concentration of 50 mass% to prepare coating agents for a composition for a print through layer and a composition for a print recognition layer.

(A) Polymer component

(A-1) (meth) acrylate copolymer obtained by copolymerizing 85 parts by mass of methyl acrylate and 15 parts by mass of 2-hydroxyethyl acrylate

(A-2) A (meth) acrylic ester copolymer obtained by copolymerizing 10 parts by mass of n-butyl acrylate, 70 parts by mass of methyl acrylate, 5 parts by mass of glycidyl methacrylate, and 15 parts by mass of 2-hydroxyethyl acrylate

(B) Curing component (thermosetting component)

(B-1) mixture of liquid bisphenol A epoxy resin and acrylic Polymer Fine particles (epoxy equivalent 235g/eq, molecular weight 380)

(B-2) solid bisphenol A type epoxy resin (epoxy equivalent: 850g/eq, softening point: 93 ℃, molecular weight: 1700)

(B-3) Dicyclopentadiene-type epoxy resin (epoxy equivalent: 258g/eq, softening Point: 61 ℃ C.)

(C) Curing agent: small particle size dicyanodiamine (average particle size 7 μm, maximum particle size 25 μm)

(D) Curing accelerator: imidazole-based curing accelerators (average particle size of 5 μm, maximum particle size of 20 μm)

(E) Filling material

(E-1) spherical fused silica Filler (manufactured by Admatechs, Inc., SC2050MB)

(E-2) epoxy-modified spherical silica Filler (Admatechs Co., SC2050MA, average particle diameter of 0.5 μm and maximum particle diameter of 2 μm)

(F) Coupling agent: an epoxy group-containing oligomer-type silane coupling agent (X-41-1056, epoxy equivalent of 280g/eq, manufactured by Shin-Etsu Silicone Co., Ltd.)

(G) Colorant:

(G-1) carbon Black (MA 600, average particle diameter 20nm, manufactured by Mitsubishi Chemical Corporation)

(G-2) yellow-based Mixed colorant

(G-3) cyan-based Mixed colorant

(G-4) white Mixed colorant

(G-5) Red Mixed colorant

(H) A crosslinking agent: isocyanate crosslinking agent (TOYO INK CO., manufactured by LTD., BHS-8515)

[ Table 1]

A first release film (manufactured by LINTEC Corporation, product name "SP-PET 381031") having a thickness of 38 μm and formed by forming a silicone-based release agent layer on one surface of a polyethylene terephthalate (PET) film, and a second release film (manufactured by LINTEC Corporation, product name "SP-PET 381130") having a thickness of 38 μm and formed by forming a silicone-based release agent layer on one surface of a PET film were prepared.

First, the above-mentioned coating agent for a through-print layer was applied to the release surface of the first release film using a blade coater so that the thickness of the through-print layer was 5 μm, and dried, thereby forming a through-print layer. Then, the peeling surfaces of the second peeling films were superimposed on the surfaces of the print-through layers, and the two were bonded to each other, thereby obtaining color difference evaluation samples α -1 and α -2 in which the peeling films were disposed on both main surfaces of the print-through layers.

In the same manner, using the coating agent for the print recognition layer, samples β -1 to β -8 for color difference evaluation were obtained in which release films were disposed on both main surfaces of the print recognition layer. The print discrimination layer had a thickness of 20 μm.

(preparation of protective film-Forming sheet)

Using some of the samples for color difference evaluation prepared above, the second release film of the samples for color difference evaluation of the print through layer and the samples for color difference evaluation of the print recognition layer were peeled off in such a manner as to prepare the combinations shown in table 2, and the surfaces of the exposed print through layer and the exposed print recognition layer were bonded to each other, thereby preparing the sheets for protective film formation of examples 1 to 8 and comparative examples 1 to 3 in which release films were disposed on both main surfaces of the protective film formation film composed of the two layers of the print through layer and the print recognition layer. In comparative examples 1 and 2, a protective film-forming sheet was prepared without using a print recognition layer. In comparative example 3, a protective film-forming sheet was prepared by laminating two print-through layers.

The obtained specimen for evaluating color difference and the sheet for forming a protective film were used to perform the following measurement and evaluation.

(color difference between printing through layer and printing identification layer)

The obtained samples α -1, α -2, and β -1 to β -8 for color difference evaluation were heated at 130 ℃ for 2 hours to cure the print penetrating layer and the print discriminating layer. The release film was peeled from the cured sample for color difference evaluation, and heated under conditions simulating reflow treatment (maximum heating temperature 260 ℃ C., heating time 5 minutes). The heated print-penetrating layer or print-recognizing layer was measured by CIE1976L in reflectance measurement with a C/2 light source using a spectrocolorimeter (NIPPON DENSHOKU industies co., ltd., SE6000) ^* a ^* b ^* L defined in the color system ^* 、a ^* And b ^* And calculating the color difference Delta E of the combination shown in Table 2 according to the following formula ^* _ab . The results are shown in table 2.

ΔE ^* _ab ＝[(ΔL ^* ) ² +(Δa ^* ) ² +(Δb ^* ) ² ] ^1/2

Δ L ═ L of the printed through layer ^* L with print recognition layer ^* Difference between (L) ^* ₁ -L ^* ₂ )

Δ a ═ a of the print penetration layer ^* And a of print recognition layer ^* Difference (a) ^* ₁ -a ^* ₂ )

Δ b ═ b of the printed through layer ^* And b of print recognition layer ^* A difference of (b ^* ₁ -b ^* ₂ )

(evaluation of laser printing visibility)

The protective film-forming sheets of examples and comparative examples were heated at 130 ℃ for 2 hours to cure the protective film-forming films (the print-through layer and the print-recognition layer), thereby forming a protective film. The release film was peeled off from the cured protective film-forming sheet, and then the protective film was irradiated with laser light from the front surface side of the print-through layer by using a printer (CSM 300M, manufactured by EO corporation, wavelength 532nm) so that the laser light penetrates the print-through layer with the output adjusted, thereby printing a print pattern shown below. After printing, the protective film was heated under conditions simulating reflow treatment (maximum heating temperature of 260 ℃ C., heating time of 5 minutes). In comparative examples 1 and 2, since there was no print-identifying layer, printing was performed by changing the surface state of the print-passing layer with a laser in the conventional manner.

Printing a pattern: ABC0123456789

Character size: 300 μm (height) × 200 μm (width)

Line width of text: 35 μm

The characters printed on the heated protective film were visually observed by 5 observers at a visual distance of 15cm, and were evaluated for visibility according to the criteria shown below. The results are shown in table 2.

Very good: 5 persons can recognize the information.

O: 3 or 4 of the 5 persons can recognize.

X: 2 out of 5 persons can be identified below.

[ Table 2]

As confirmed from table 2, when the color difference between the print penetrating layer and the print recognition layer was within the above range, the recognizability evaluation was "excellent" or "good". On the other hand, it was confirmed that when the color difference between the print-through layer and the print-recognition layer was outside the above range, the recognizability was evaluated as x.

Claims

1. A protective film forming film for forming a protective film, wherein,

the protective film forming film has a print penetrating layer and a print recognizing layer, and is represented by CIE1976L ^* a ^* b ^* In the color space, the color difference between the print penetrating layer and the print recognition layer after heating at 260 ℃ for 5 minutes is 50 or more.

2. The protective film forming film according to claim 1, wherein the protective film forming film is composed of the through-lettering layer and the lettering recognition layer.

3. The protective film forming film according to claim 1 or 2, wherein the thickness of the print-through layer is 5 μm or less.

4. The protective film forming film according to any one of claims 1 to 3, wherein the print recognition layer has CIE1976L ^* a ^* b ^* L in color space ^* Is 50 or more.

5. The protective film forming film according to claim 4, wherein the print recognition layer has CIE1976L ^* a ^* b ^* A in color space ^* Is 40 or more.

6. The protective film forming film according to any one of claims 1 to 4, wherein the print recognition layer has CIE1976L ^* a ^* b ^* B in color space ^* Is 30 or more.

7. A protective film-forming sheet comprising the protective film-forming film according to any one of claims 1 to 6 and a release film arranged so as to be peelable on at least one main surface of the protective film-forming film.

8. A composite sheet for forming a protective film, comprising a support sheet and the protective film forming film according to any one of claims 1 to 6 formed on the support sheet.

9. A kit comprising a print recognition layer for affixing to a workpiece and a laminate comprising a support sheet and a print-through layer formed on the support sheet for affixing to the print recognition layer,

in CIE1976L ^* a ^* b ^* In the color space, the color difference between the print penetrating layer and the print recognition layer after heating at 260 ℃ for 5 minutes is 50 or more.

10. A method for manufacturing a device, comprising the steps of:

a step of attaching a protective film-forming film of the protective film-forming sheet according to claim 7 or a protective film-forming film of the protective film-forming composite sheet according to claim 8 to the back surface of a workpiece;

forming the attached protective film into a protective film;

a step of performing laser marking on the protective film or the protective film forming film;

obtaining a plurality of workpiece processed products with a protective film or a protective film forming film by singulating the workpiece having the protective film or the protective film forming film on the back surface;

and heating the work with the protective film disposed on the substrate and the substrate.

11. A workpiece with a protective film, wherein a protective film obtained by forming the protective film according to any one of claims 1 to 6 into a protective film is formed on the workpiece.