WO2014142151A1 - Composite sheet for protective film formation, method for producing composite sheet for protective film formation, and method for producing chip with protective film - Google Patents

Abstract

[Problem] To provide a composite sheet for protective film formation, which has good holding power with respect to a jig such as a ring frame and excellent releasability at the time of pick-up, and which is capable of preventing defects that are caused by decrease in adhesion between a second adhesive layer and an adhesive layer (a first adhesive layer) of an adhesive sheet. [Solution] A composite sheet for protective film formation according to the present invention comprises a film for protective film formation on a first adhesive layer of an adhesive sheet, which comprises a base and the first adhesive layer as constituent layers, with a second adhesive layer being interposed therebetween. The shape of the second adhesive layer is contained in the shape of the adhesive sheet when viewed in plan; the first adhesive layer is formed of an energy ray-curable adhesive or an adhesive that is obtained by curing an energy ray-curable adhesive; the second adhesive layer is formed of an adhesive that is obtained by curing an energy ray-curable adhesive; and the tensile modulus of the second adhesive layer at 25°C is 200-2,000 MPa.

Description

Protective film forming composite sheet, method for manufacturing protective film forming composite sheet, and method for manufacturing chip with protective film

The present invention relates to a composite sheet for forming a protective film, which can form a protective film on a semiconductor wafer or semiconductor chip and can improve the manufacturing efficiency of the semiconductor chip. In particular, the present invention relates to a composite sheet for forming a protective film used for manufacturing a semiconductor chip mounted by a so-called face-down method.

In recent years, semiconductor devices have been manufactured using a so-called “face-down” mounting method. In the face-down method, a semiconductor chip (hereinafter simply referred to as “chip”) having electrodes such as bumps on a circuit surface is used, and the electrodes are bonded to a substrate. For this reason, the surface (chip back surface) opposite to the circuit surface of the chip may be exposed.

The exposed chip back surface may be protected by an organic film. Conventionally, a chip having a protective film made of an organic film is obtained by applying a liquid resin to the back surface of a wafer by spin coating, drying and curing, and cutting the protective film together with the wafer. However, since the thickness accuracy of the protective film formed in this way is not sufficient, the product yield may be lowered.

In order to solve the above problem, a dicing tape-integrated film for semiconductor back surface in which a film for semiconductor back surface is laminated on a dicing tape is disclosed (Patent Document 1).

The dicing tape that supports the film for semiconductor back surface is required to have a good holding force against a jig such as a ring frame and a good releasability at the time of pickup.

With the recent thinning and miniaturization of semiconductor packages, it is necessary to achieve the above-mentioned holding power and peelability at the same time, making simultaneous resolution extremely difficult. In order to obtain an excellent peelability for picking up a chip, it is conceivable that the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer of the dicing tape is made to have a low pressure-sensitive adhesive property. However, when the pressure-sensitive adhesive has low adhesiveness, there is a concern that good holding power for the ring frame is lost.

In order to solve such a problem, in Patent Document 1, an additional adhesive layer is provided between the film for semiconductor back surface and the dicing tape to achieve both the holding force for the ring frame and the peelability at the time of pickup. ing. In manufacturing a semiconductor device using such a dicing tape integrated semiconductor back film, the semiconductor back film is cured after a chip having the semiconductor back film is bonded to a substrate or the like.

JP 2012-33637 A

However, the dicing tape-integrated film for semiconductor back surface disclosed in Patent Document 1 may not always have sufficient pickup properties (peelability). After applying the dicing tape integrated semiconductor back film to the semiconductor wafer, the semiconductor back film is thermally cured, and then used in the process of dicing and picking up. It may become strong and the pick-up property may deteriorate. With the dicing tape-integrated semiconductor back film of Patent Document 1, there is a concern that the pickup property cannot be maintained in a process where such conditions are more severe.

Accordingly, the adhesive layer (second adhesive layer in the present invention) provided between the film for semiconductor back surface and the dicing tape (adhesive sheet in the present invention) is required to have good pick-up property, and the adhesive of the adhesive layer When the property is lowered, the adhesion between the dicing tape and the pressure-sensitive adhesive layer may be lowered. As a result, the adhesive layer may remain on the film for semiconductor back surface at the time of pick-up. Such a decrease in adhesiveness cannot be dealt with simply by improving the adhesiveness of the dicing sheet (adhesive sheet).

An object of the present invention is to provide a good holding force for a jig such as a ring frame, excellent releasability at the time of pick-up, and a second adhesive layer and an adhesive layer (first adhesive layer) in the adhesive sheet. An object of the present invention is to provide a composite sheet for forming a protective film that can prevent problems caused by a decrease in adhesiveness.

The present invention includes the following gist.
[1] A protective film-forming composite sheet in which a protective film-forming film is provided on a first pressure-sensitive adhesive layer of a pressure-sensitive adhesive sheet comprising a base material and a first pressure-sensitive adhesive layer as constituent layers via a second pressure-sensitive adhesive layer Because
The shape of the second pressure-sensitive adhesive layer in plan view is a shape included in the shape of the pressure-sensitive adhesive sheet in plan view,
The first pressure-sensitive adhesive layer is composed of an energy beam-curable pressure-sensitive adhesive or an energy beam-cured pressure-sensitive adhesive,
The second pressure-sensitive adhesive layer is made of a pressure-sensitive adhesive obtained by curing an energy ray-curable pressure-sensitive adhesive,
A composite sheet for forming a protective film, wherein the second adhesive layer has a tensile elastic modulus at 25 ° C. of 200 to 2000 MPa.

[2] The composite sheet for forming a protective film according to [1], wherein the second pressure-sensitive adhesive layer has a tensile elastic modulus at 25 ° C. of 500 to 2000 MPa.

[3] The composite sheet for forming a protective film according to [1] or [2], wherein the protective film-forming film is thermosetting.

[4] The composite sheet for forming a protective film according to any one of [1] to [3], wherein the base material is a film containing one or more layers of polypropylene film.

[5] In an adhesive strength measurement test in which the adhesive sheet is peeled off from the second adhesive layer, at least one of the first adhesive layer and the second adhesive layer is agglomerated and broken, or the adhesive strength is 0.8 N / 25 mm. The composite sheet for forming a protective film according to any one of [1] to [4].

[6] A method for producing the composite sheet for forming a protective film according to any one of [1] to [5],
A step of laminating a second pressure-sensitive adhesive layer on the first pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet,
The manufacturing method of the composite sheet for protective film formation which has the process of hardening a 1st adhesive layer, after laminating | stacking a 1st adhesive layer and a 2nd adhesive layer.

[7] A method for manufacturing a chip with a protective film, wherein the following steps (1) to (3) are performed in this order;
Step (1): A step of attaching the protective film-forming film of the protective film-forming composite sheet according to any one of [1] to [5] to a workpiece,
Step (2): a step of heat-curing the protective film-forming film to obtain a protective film,
Step (3): A step of separating the protective film and the second pressure-sensitive adhesive layer.

According to the composite sheet for forming a protective film of the present invention, it has a good holding power with respect to a jig such as a ring frame, is excellent in the pick-up property of a chip with a protective film, and has an adhesive layer (shown in FIG. The malfunction resulting from the adhesive fall of the 2nd adhesive layer 3) and the adhesive layer (1st adhesive layer 2 shown in FIG. 1) in an adhesive sheet can be prevented.

Sectional drawing of the composite sheet for protective film formation which concerns on this invention is shown.

Hereinafter, the detail of the composite sheet for protective film formation of this invention is demonstrated.
As shown in FIG. 1, a protective film-forming composite sheet 10 is formed on a first adhesive layer 2 of an adhesive sheet 5 including a substrate 1 and a first adhesive layer 2 as constituent layers. Is provided via the second pressure-sensitive adhesive layer 3.

〔Base material〕
The substrate is not particularly limited. For example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate. Film, polyurethane film, ethylene vinyl acetate copolymer film, ionomer resin film, ethylene / (meth) acrylic acid copolymer film, ethylene / (meth) acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film A fluororesin film or the like is used. These crosslinked films are also used. Furthermore, these laminated films may be sufficient. Among these, the base material composed of a film containing one or more layers of polypropylene film has high heat resistance, and the deformation is small even when the adhesive sheet is bonded when the protective film-forming film is cured. It is preferable because it can be easily restored, can easily maintain pickup properties, and can be expanded.

The thickness of the substrate is not particularly limited, and is preferably 30 to 300 μm, more preferably 50 to 200 μm. By setting the thickness of the base material within the above range, the composite sheet for forming a protective film has sufficient flexibility, and therefore exhibits good adhesiveness to a workpiece (for example, a semiconductor wafer).

Moreover, in order to improve the adhesiveness with the first pressure-sensitive adhesive layer, the surface where the base material is in contact with the first pressure-sensitive adhesive layer may be subjected to corona treatment or other layers such as a primer.

[First adhesive layer]
A 1st adhesive layer consists of an adhesive which hardened | cured energy-beam curable adhesive or energy-beam curable adhesive.
By constituting the first pressure-sensitive adhesive layer with the above-mentioned pressure-sensitive adhesive, it is possible to improve the adhesion with the second pressure-sensitive adhesive layer described later. This is because the energy ray-polymerizable groups in the energy ray-curable pressure-sensitive adhesive contained in the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer, which will be described later, have a high affinity between the energy ray-polymerizable groups. Moreover, it is thought that it originates in energy beam polymeric groups couple | bonding depending on the case. Note that the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are made of a pressure-sensitive adhesive obtained by curing the energy ray-curable pressure-sensitive adhesive. It is considered that the bond between the energy beam polymerizable groups can occur because the energy beam polymerizable group) of the reaction exists. Moreover, in the manufacturing process of the protective film-forming composite sheet described later, even when energy beam irradiation is not performed after laminating the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer, the energy beam polymerizable groups are bonded to each other. This reaction is considered to proceed slowly after the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are laminated, and a bond is formed.
As a result, when manufacturing a chip with a protective film, the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are stronger than the adhesive force between the protective film obtained by heating and curing the protective film-forming film and the second pressure-sensitive adhesive layer. Due to the stronger adhesive force between the pressure-sensitive adhesive layer, it becomes easy to perform separation between the protective film and the second pressure-sensitive adhesive layer.

The energy beam polymerizable group in the present invention is a functional group having a polymerizable carbon-carbon double bond, and specific examples thereof include a vinyl group, an allyl group, a (meth) acryloyl group, and the like. (Meth) acryloyl group is mentioned. The energy beam polymerizable group in the present invention does not mean a double bond having no polymerizability because it generates a radical in the presence of a radical and easily causes a polyaddition reaction. For example, each component constituting the energy ray-curable pressure-sensitive adhesive may contain an aromatic ring, but the unsaturated structure of the aromatic ring does not mean the energy ray polymerizable group in the present invention.

The pressure-sensitive adhesive usually contains a polymer (A) and also contains an energy ray curable compound (B). The energy ray-curable compound (B) contains an energy ray-polymerizable group, has a function of being polymerized and cured when irradiated with energy rays such as ultraviolet rays and electron beams, and reducing the adhesiveness of the pressure-sensitive adhesive.
Moreover, as what has the property of said component (A) and (B), it describes as an energy-beam curable polymer (henceforth component (AB)) by which an energy-beam polymeric group is couple | bonded with the principal chain or the side chain. May be used). Such an energy beam curable polymer (AB) has the property of having both a function as a polymer and energy beam curability.

The energy ray-curable pressure-sensitive adhesive is not particularly limited, but will be specifically described with an acrylic pressure-sensitive adhesive as an example. The acrylic pressure-sensitive adhesive contains an acrylic polymer (A1) as the polymer (A).

As the acrylic polymer (A1), a conventionally known acrylic polymer can be used. The weight average molecular weight (Mw) of the acrylic polymer (A1) is preferably 10,000 to 2,000,000, more preferably 100,000 to 1,500,000. The glass transition temperature (Tg) of the acrylic polymer (A1) is preferably in the range of −70 to 30 ° C., more preferably in the range of −60 to 20 ° C.

The monomer constituting the acrylic polymer (A1) includes at least one (meth) acrylic acid ester monomer or a derivative thereof.
Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl ( Alkyl groups such as (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, tetradecyl (meth) acrylate, octadecyl (meth) acrylate and the like have 1 carbon atom Alkyl (meth) acrylate which is -18; cycloalkyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (Meth) acrylates having a cyclic skeleton such as (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, imide (meth) acrylate; hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl Hydroxyl group-containing (meth) acrylates such as (meth) acrylate and 2-hydroxybutyl (meth) acrylate; Epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate and 3,4-epoxycyclohexylmethyl (meth) acrylate; monomethyl Amino group-containing (meth) acrylates such as amino (meth) acrylate, monoethylamino (meth) acrylate, diethylamino (meth) acrylate; 2- (meth) acryloyloxyethyl phthalate And carboxyl group-containing (meth) acrylates such as 2- (meth) acryloyloxypropyl phthalate.
Further, (meth) acrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene or the like may be copolymerized.
These may be used alone or in combination of two or more.

In addition, in this specification, (meth) acryl may be used in the meaning including both acryl and methacryl.

The acrylic polymer (A1) may be cross-linked. In the case of crosslinking the acrylic polymer (A1), the acrylic polymer (A1) before being crosslinked has a crosslinkable functional group such as a hydroxyl group, and a composition for forming the first pressure-sensitive adhesive layer. A cross-linking agent is added to the product. The acrylic polymer (A1) is crosslinked by the reaction between the crosslinkable functional group and the functional group of the crosslinking agent. By crosslinking the acrylic polymer (A1), the cohesive force of the first pressure-sensitive adhesive layer can be adjusted.

Examples of the crosslinking agent include organic polyvalent isocyanate compounds and organic polyvalent imine compounds.

Examples of organic polyvalent isocyanate compounds include aromatic polyvalent isocyanate compounds, aliphatic polyvalent isocyanate compounds, alicyclic polyvalent isocyanate compounds, trimers of these organic polyvalent isocyanate compounds, and these organic polyvalent isocyanate compounds. Examples thereof include terminal isocyanate urethane prepolymers obtained by reacting with a polyol compound.

Specific examples of the organic polyvalent isocyanate compound include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylene 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 these Examples thereof include polyhydric alcohol adducts.

Specific examples of organic polyvalent imine compounds include N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, tetramethylol. Mention may be made of methane-tri-β-aziridinylpropionate and N, N′-toluene-2,4-bis (1-aziridinecarboxamide) triethylenemelamine.

The crosslinking agent is usually used in a ratio of 0.01 to 20 parts by weight, preferably 0.1 to 15 parts by weight, more preferably 0.5 to 12 parts by weight with respect to 100 parts by weight of the acrylic polymer before crosslinking. It is done.

In the present invention, for the aspect of the content of the component constituting the first pressure-sensitive adhesive layer, when determining the content of the acrylic polymer as a reference, when the acrylic polymer is a crosslinked acrylic polymer, The reference content is the content of the acrylic polymer before being crosslinked.

The energy ray-curable compound (B) is a compound that is polymerized and cured when irradiated with energy rays such as ultraviolet rays and electron beams. Examples of the energy ray curable compounds include low molecular weight compounds (monofunctional and polyfunctional monomers and oligomers) having an energy ray polymerizable group, and specifically include trimethylolpropane triacrylate and tetramethylolmethane. Acrylates such as tetraacrylate, pentaerythritol triacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, dicyclopentadiene dimethoxydiacrylate, Cyclic aliphatic skeleton-containing acrylates such as isobornyl acrylate, polyethylene glycol diacrylate, oligoester acrylate, urethane acrylate Goma, epoxy-modified acrylates, polyether acrylates, acrylate compounds such as itaconic acid oligomer is used. Such a compound has an energy ray polymerizable group in the molecule and usually has a molecular weight of about 100 to 30,000, preferably about 300 to 10,000.

In general, the amount of the low molecular weight compound having an energy ray polymerizable group is preferably 0 to 200 parts by mass relative to 100 parts by mass of the component (A) (including the energy ray curable polymer (AB) described later). The ratio is preferably 1 to 100 parts by mass, more preferably about 1 to 30 parts by mass.

The energy beam curable polymer (AB) having the properties of the components (A) and (B) is formed by bonding an energy beam polymerizable group to the main chain, side chain or terminal of the polymer.

The energy ray curable polymer bonded to the main chain, side chain or terminal of the energy ray curable polymer is an alkylene group, alkyleneoxy group or polyalkyleneoxy group via the main chain or side chain of the energy ray curable polymer. Or you may couple | bond with the terminal.

The weight average molecular weight (Mw) of the energy beam curable polymer (AB) is preferably 10,000 to 2,000,000, and more preferably 100,000 to 1,500,000. The glass transition temperature (Tg) of the energy beam curable polymer (AB) is preferably in the range of −70 to 30 ° C., more preferably −60 to 20 ° C. In the case of an energy ray curable polymer (AB) obtained by reacting an acrylic polymer containing a functional group such as a hydroxy group described later with a polymerizable group-containing compound, Tg is a polymerizable group. It is Tg of the acrylic polymer before making it react with a containing compound.

The energy ray curable polymer (AB) includes, for example, an acrylic polymer containing a functional group such as a hydroxy group, a carboxyl group, an amino group, a substituted amino group, and an epoxy group, and a substituent that reacts with the functional group. It is obtained by reacting a polymerizable group-containing compound having 1 to 5 energy beam polymerizable carbon-carbon double bonds per molecule. The acrylic polymer includes a (meth) acrylic acid ester monomer having a functional group such as a hydroxy group, a carboxyl group, an amino group, a substituted amino group, and an epoxy group or a derivative thereof, and a monomer constituting the component (A) described above. A copolymer consisting of Examples of the polymerizable group-containing compound include (meth) acryloyloxyethyl isocyanate, meta-isopropenyl-α, α-dimethylbenzyl isocyanate, (meth) acryloyl isocyanate, allyl isocyanate, glycidyl (meth) acrylate, and (meth) acrylic acid. Etc.

When the energy ray curable polymer (AB) is obtained by reacting an acrylic polymer containing a functional group such as a hydroxy group with a polymerizable group-containing compound, the energy ray curable polymer (AB) is Like the above-mentioned acrylic polymer (A1), it may be crosslinked.

The acrylic pressure-sensitive adhesive containing the acrylic polymer (A1), the energy ray curable compound (B) and / or the energy ray curable polymer (AB) as described above is cured by irradiation with energy rays. Specifically, ultraviolet rays, electron beams, etc. are used as the energy rays.

Also, by combining a photopolymerization initiator with the energy beam curable compound (B) or the energy beam curable polymer (AB), the polymerization curing time can be shortened and the amount of light irradiation can be decreased.

Examples of such photopolymerization initiators include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, benzoin dimethyl ketal, 2,4-diethyl Thioxanthone, α-hydroxycyclohexyl phenyl ketone, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, 1,2-diphenylmethane, 2-hydroxy-2-methyl-1- [4- (1-Methylvinyl) phenyl] propanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide and β-chloranth Examples include laquinone. A photoinitiator can be used individually by 1 type or in combination of 2 or more types.

The blending ratio of the photopolymerization initiator is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the energy beam curable compound (B) and the energy beam curable polymer (AB), and is preferably 1 to 5 parts by mass. More preferably, it is included.
If the blending ratio of the photopolymerization initiator is less than 0.1 parts by mass, satisfactory curability may not be obtained due to insufficient photopolymerization, and if it exceeds 10 parts by mass, a residue that does not contribute to photopolymerization is generated. May cause malfunctions.

The first pressure-sensitive adhesive layer may be a pressure-sensitive adhesive layer made of a pressure-sensitive adhesive obtained by curing an energy ray-curable pressure-sensitive adhesive. The pressure-sensitive adhesive layer made of the pressure-sensitive adhesive obtained by curing the energy beam-curable pressure-sensitive adhesive is obtained by curing the energy beam-curable pressure-sensitive adhesive by energy beam irradiation described in the method for producing a protective film-forming composite sheet described later. Is. The same applies to the second pressure-sensitive adhesive layer described later.

The thickness of the first pressure-sensitive adhesive layer is not particularly limited, but is preferably 3 to 80 μm, more preferably 4 to 50 μm, and particularly preferably 5 to 30 μm.

[Second adhesive layer]
A 2nd adhesive layer consists of an adhesive which hardened the energy-beam curable adhesive. As the energy ray-curable pressure-sensitive adhesive, the same one as the energy ray-curable pressure-sensitive adhesive in the first pressure-sensitive adhesive layer described above can be used, but a low molecular weight component (for example, energy ray-curable property) to the protective film-forming film. From the viewpoint of suppressing the migration of the compound and the like, it is preferable to use an energy beam curable polymer as the energy beam curable adhesive. When the low molecular weight component is transferred to the protective film-forming film, the curability of the protective film-forming film is lowered, and the reliability of the semiconductor device using the chip with the protective film may be deteriorated. The energy ray curable polymer is not particularly limited, and for example, the same energy ray curable pressure sensitive adhesive contained in the first pressure sensitive adhesive layer can be used.

Further, the tensile elastic modulus at 25 ° C. of the second pressure-sensitive adhesive layer is 200 to 2000 MPa.
According to the 2nd adhesive layer of such composition, while being excellent in adhesiveness with the 1st adhesive layer, since it is excellent in releasability from a protective film, the pick-up property of a chip with a protective film improves. The tensile elastic modulus at 25 ° C. of the second pressure-sensitive adhesive layer is preferably 500 to 2000 MPa, more preferably 500 to 1500 MPa. If it is such a range, the pick-up property of the chip | tip with a protective film will improve further. In particular, even when the protective film-forming film is put into the thermosetting process together with the adhesive sheet without removing the adhesive sheet of the protective film-forming composite sheet, the pickup property of the chip with the protective film is excellent. Become. The tensile elastic modulus at 25 ° C. of the second pressure-sensitive adhesive layer can be controlled by selecting a monomer constituting the acrylic polymer. Especially, control of the tensile elasticity modulus in 25 degreeC of a 2nd adhesive layer becomes easy by adjusting the compounding quantity of vinyl acetate. Moreover, when using an energy-beam curable polymer, the tensile elasticity modulus in 25 degreeC of a 2nd adhesive layer can be controlled with the compounding quantity of the polymeric group containing compound made to react with the acrylic polymer containing a functional group. .

The thickness of the second pressure-sensitive adhesive layer is not particularly limited, but is preferably 2 to 80 μm, more preferably 3 to 50 μm, and particularly preferably 5 to 10 μm.

The shape of the second pressure-sensitive adhesive layer in plan view is not particularly limited as long as it is a shape included in the shape of the above-described pressure-sensitive adhesive sheet in plan view. For example, the shape that can include substantially the same shape as the workpiece or the shape of the workpiece. Is mentioned.

[Protective film forming film]
The protective film-forming film may be any film having (1) sheet shape maintaining property, (2) initial adhesiveness, and (3) curability.

The protective film-forming film can be provided with (1) sheet shape maintainability and (3) curability by adding a binder component, and the binder component includes a first component containing a polymer component and a curable component. A second binder component containing a curable polymer component having the properties of a binder component or a polymer component and a curable component can be used.

(2) The initial adhesiveness may be pressure-sensitive adhesiveness, and is a property of being softened and bonded by heat. There may be. (2) The initial adhesiveness is usually controlled by adjusting various properties of the binder component and adjusting the blending amount of the inorganic filler described later.

(First binder component)
A 1st binder component provides a sheet | seat shape maintainability and curability to the film for protective film formation by containing a polymer component and a sclerosing | hardenable component. In addition, the 1st binder component does not contain a curable polymer component for convenience to distinguish from the 2nd binder component.

(A) Polymer component The polymer component (a) is added to the protective film-forming film mainly for the purpose of imparting sheet shape maintenance to the protective film-forming film.

In order to achieve the above object, the weight average molecular weight (Mw) of the polymer component (a) is usually 20,000 or more, preferably 20,000 to 3,000,000. The value of the weight average molecular weight (Mw) is a value when measured by a gel permeation chromatography method (GPC) method (polystyrene standard). The measurement by such a method is carried out, for example, by using a high-speed GPC apparatus “HLC-8120GPC” manufactured by Tosoh Corporation and a high-speed column “TSK gold column H _XL- H”, “TSK Gel GMH _XL ”, “TSK Gel G2000 H _XL ”. (The above, all manufactured by Tosoh Corporation) are connected in this order, and the detector is used as a differential refractometer at a column temperature of 40 ° C. and a liquid feed rate of 1.0 mL / min.

In addition, for convenience to distinguish from the curable polymer component (ab) described later, the polymer component (a) does not have a curing functional functional group described later.

Examples of the polymer component (a) include acrylic polymers, polyesters, phenoxy resins (for the purpose of distinguishing from curable polymers described later, those having no epoxy group), polycarbonates, polyethers, polyurethanes, polysiloxanes. A rubber polymer or the like can be used. In addition, an acrylic urethane resin obtained by reacting a urethane prepolymer having an isocyanate group at a molecular terminal with an acrylic polyol having an hydroxyl group and an acrylic polyol having a combination of two or more of these, Also good. Furthermore, two or more of these may be used in combination, including a polymer in which two or more are bonded.
When the acrylic polymer (a1) is used as the polymer component (a), the same polymer as the acrylic polymer (A1) contained in the above acrylic pressure-sensitive adhesive can be used.

Further, as the polymer component (a), polyester, phenoxy resin (for the purpose of distinguishing from the curable polymer described later, limited to those having no epoxy group), polycarbonate, polyether, polyurethane, polysiloxane, rubber-based weight One type of non-acrylic resin (a2) selected from a combination or a combination of two or more types thereof or a combination of two or more types may be used. Such a resin preferably has a weight average molecular weight of 20,000 to 100,000, more preferably 20,000 to 80,000.

The glass transition temperature of the non-acrylic resin (a2) is preferably in the range of −30 to 150 ° C., more preferably in the range of −20 to 120 ° C.

When the non-acrylic resin (a2) is used in combination with the acrylic polymer (a1), the cured protective film-forming film (protective film) is transferred to the workpiece using a protective film-forming composite sheet described later. In doing so, delamination of the protective film and the second pressure-sensitive adhesive layer can be easily performed. Further, the protective film-forming film tends to follow the unevenness of the transfer surface.

When the non-acrylic resin (a2) is used in combination with the acrylic polymer (a1), the content of the non-acrylic resin (a2) is such that the non-acrylic resin (a2) and the acrylic polymer (a1) Is usually in the range of 1:99 to 60:40, preferably 1:99 to 30:70. When the content of the non-acrylic resin (a2) is in this range, the above effect can be obtained to a higher degree.

(B) Curable component The curable component (b) is added to the protective film-forming film mainly for the purpose of imparting curability to the protective film-forming film. As the curable component (b), a thermosetting component (b1) can be used. When the protective film-forming film contains a thermosetting component (b1), the protective film-forming film becomes thermosetting. The thermosetting component (b1) contains at least a compound having a functional group that reacts by heating. Curing is realized by the functional groups of the curable component (b) reacting to form a three-dimensional network structure. Since the curable component (b) is used in combination with the polymer component (a), the increase in the viscosity of the coating composition for forming the protective film-forming film is suppressed, and the handleability is improved. Therefore, the weight average molecular weight (Mw) is usually 10,000 or less, preferably 100 to 10,000.

(B1) Thermosetting component As the thermosetting component (b1), for example, an epoxy thermosetting component is preferable. The epoxy thermosetting component preferably contains a compound (b11) having an epoxy group and a combination of the compound (b11) having an epoxy group and a thermosetting agent (b12).

(B11) Compound having an epoxy group As the compound having an epoxy group (hereinafter sometimes referred to as "epoxy compound"), a conventionally known compound can be used. Specifically, polyfunctional epoxy resin, bisphenol A diglycidyl ether and its hydrogenated product, orthocresol novolac epoxy resin, dicyclopentadiene type epoxy resin, biphenyl type epoxy resin, bisphenol A type epoxy resin, bisphenol F type Examples thereof include epoxy compounds having two or more functional groups in the molecule, such as epoxy resins and phenylene skeleton type epoxy resins. These can be used individually by 1 type or in combination of 2 or more types.

The content of the epoxy compound (b11) is preferably 1 to 1500 parts by mass, and more preferably 3 to 1200 parts by mass with respect to 100 parts by mass of the polymer component (a).

(B12) Thermosetting agent The thermosetting agent (b12) functions as a curing agent for the epoxy compound. A preferable thermosetting agent includes a compound having two or more functional groups capable of reacting with an epoxy group in one molecule. Examples of the functional group include a phenolic hydroxyl group, an alcoholic hydroxyl group, an amino group, a carboxyl group, and an acid anhydride. Of these, phenolic hydroxyl groups, amino groups, acid anhydrides and the like are preferable, and phenolic hydroxyl groups and amino groups are more preferable.

Specific examples of phenolic curing agents (thermosetting agents having a phenolic hydroxyl group) include polyfunctional phenolic resins, biphenols, novolac phenolic resins, dicyclopentadiene phenolic resins, zylocic phenolic resins, and aralkyl phenolic resins. Is mentioned. A specific example of the amine curing agent (thermosetting agent having an amino group) is DICY (dicyandiamide). These can be used individually by 1 type or in mixture of 2 or more types.

The content of the thermosetting agent (b12) is preferably 0.1 to 500 parts by mass, and more preferably 1 to 200 parts by mass with respect to 100 parts by mass of the epoxy compound.

(B13) Curing accelerator The curing accelerator (b13) may be used to adjust the rate of thermal curing of the protective film-forming film. The curing accelerator (b13) is preferably used particularly when an epoxy thermosetting component is used as the thermosetting component.

Preferred curing accelerators (b13) include tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris (dimethylaminomethyl) phenol; 2-methylimidazole, 2-phenylimidazole, 2 -Imidazoles such as phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole; organics such as tributylphosphine, diphenylphosphine, triphenylphosphine Phosphines; and tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphinetetraphenylborate. These can be used individually by 1 type or in mixture of 2 or more types.

The curing accelerator (b13) is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 2 parts by mass with respect to 100 parts by mass of the total amount of the epoxy compound (b11) and the thermosetting agent (b12). Included in the amount of. By containing the curing accelerator (b13) in an amount within the above range, the protective film-forming film has excellent adhesion to the workpiece even under exposure to high temperatures and high humidity, and is subjected to severe reflow conditions. High reliability can be achieved even when exposed. If the content of the curing accelerator (b13) is low, sufficient adhesion cannot be obtained due to insufficient curing, and if it is excessive, the curing accelerator (b13) having high polarity is a film for forming a protective film under high temperature and high humidity. By moving the inside to the adhesion interface side and segregating, the reliability of the semiconductor device may be lowered.

(Second binder component)
By containing the curable polymer component (ab), the second binder component imparts film forming properties (sheet forming properties) and curability to the protective film forming film.

(Ab) Curable polymer component The curable polymer component (ab) is a polymer having a functional functional group. The curing functional group is a functional group that can react with each other to form a three-dimensional network structure, and includes a functional group that reacts by heating.

The functional functional group may be added to the unit of the continuous structure that becomes the skeleton of the curable polymer, or may be added to the terminal. When the functional functional group is added in the unit of the continuous structure that becomes the skeleton of the curable polymer component, the functional functional group may be added to the side chain or directly to the main chain. Also good. The weight average molecular weight (Mw) of the curable polymer component (ab) is usually 20,000 or more from the viewpoint of achieving the purpose of imparting sheet shape maintainability to the protective film-forming film.

The functional group that reacts by heating includes an epoxy group. Examples of the curable polymer component having an epoxy group include phenoxy resins having an epoxy group, and specific product names include jER1256 and jER4250 manufactured by Mitsubishi Chemical Corporation.

Moreover, the curable polymer component which has an epoxy group is a polymer similar to the above-mentioned acrylic polymer (a1), and is polymerized using a monomer having an epoxy group as a monomer ( Epoxy group-containing acrylic polymer). Examples of such a monomer include epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate.

When an epoxy group-containing acrylic polymer is used, the preferred embodiment is the same as that of the acrylic polymer (a1).

When a curable polymer component having an epoxy group is used, a thermosetting agent (b12) or a curing accelerator (b13) may be used in the same manner as in the case of using an epoxy thermosetting component as the curable component. Good.

The second binder component may contain the above-described polymer component (a) and curable component (b) together with the curable polymer component (ab).

When the protective film-forming film contains one or both of the thermosetting component (b1) and the curable polymer component (ab), the protective film-forming film has thermosetting properties. In order to impart more sufficient thermosetting property to the protective film-forming film, it is preferable that the protective film-forming film contains at least the thermosetting component (b1). However, when the protective film-forming film contains only the thermosetting component (b1), the sheet shape maintaining property of the protective film-forming film may be inferior. Therefore, the protective film-forming film preferably contains a thermosetting component (b1) and one or both of the polymer component (a) and the curable polymer component (ab).

From the viewpoint of imparting sufficient thermosetting property to the protective film-forming film, the amount of the thermosetting component (b1) contained in the protective film-forming film is determined by the polymer component (a) and the curable polymer component ( The total amount of ab) is preferably 50 to 300 parts by mass, more preferably 70 to 250 parts by mass with respect to 100 parts by mass in total.

The protective film-forming film may contain the following components in addition to the binder component.

(C) The inorganic filler protective film-forming film may contain an inorganic filler (c). By blending the inorganic filler (c) into the protective film-forming film, the thermal expansion coefficient of the cured protective film-forming film can be adjusted, and the protective film-forming film after curing with respect to the workpiece can be adjusted. The reliability of the semiconductor device can be improved by optimizing the thermal expansion coefficient. It is also possible to reduce the moisture absorption rate of the protective film-forming film after curing.

Preferable inorganic fillers (c) include silica, alumina, talc, calcium carbonate, titanium oxide, iron oxide, silicon carbide, boron nitride and other powders, beads formed by spheroidizing them, single crystal fibers, glass fibers, and the like. . Among these, silica filler and alumina filler are preferable. The said inorganic filler can be used individually or in mixture of 2 or more types. The range of the content of the inorganic filler (c) for obtaining the above-mentioned effect more reliably is preferably 1 to 80 parts by mass with respect to 100 parts by mass of the total solid content constituting the protective film-forming film, More preferred is 5 to 75 parts by mass, and particularly preferred is 15 to 60 parts by mass.

(D) Colorant (d) can be mix | blended with the film for colorant protective film formation. By blending the colorant (d), malfunction of the semiconductor device due to infrared rays or the like generated from surrounding devices when the semiconductor device is incorporated into equipment can be prevented. Further, when the protective film forming film is engraved by means such as laser marking, there is an effect that marks such as characters and symbols can be easily recognized.
As the colorant (d), organic or inorganic pigments and dyes are used. Among these, black pigments are preferable from the viewpoint of electromagnetic wave and infrared shielding properties. Examples of the black pigment include carbon black, iron oxide, manganese dioxide, aniline black, activated carbon, and the like, but are not limited thereto. Carbon black is particularly preferable from the viewpoint of increasing the reliability of the semiconductor device. The blending amount of the colorant (d) is preferably 0.1 to 35 parts by mass, more preferably 0.5 to 25 parts by mass, particularly 100 parts by mass of the total solid content constituting the protective film-forming film. The amount is preferably 1 to 15 parts by mass.

(E) Coupling agent The coupling agent (e) having a functional group that reacts with an inorganic substance and a functional group that reacts with an organic functional group is bonded to the workpiece of the protective film-forming film and / or You may use in order to improve aggregability. Moreover, the water resistance can be improved by using a coupling agent (e), without impairing the heat resistance of the protective film obtained by hardening | curing the film for protective film formation. Examples of such coupling agents (e) include titanate coupling agents, aluminate coupling agents, silane coupling agents, and the like. Of these, silane coupling agents are preferred.

As the silane coupling agent, a silane coupling agent in which a functional group that reacts with the organic functional group is a group that reacts with a functional group of a polymer, a curable component, a curable polymer component, or the like is preferably used. .
Such silane coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ- (methacryloxy). Propyl) trimethoxysilane, γ-aminopropyltrimethoxysilane, N-6- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-6- (aminoethyl) -γ-aminopropylmethyldiethoxysilane, N -Phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis (3-triethoxysilylpropyl) tetrasulfane, methyltri Methoxysilane , Methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, and imidazolesilane. These can be used individually by 1 type or in mixture of 2 or more types.

The silane coupling agent is usually 0.1 to 20 parts by weight, preferably 0.8 parts per 100 parts by weight in total of the polymer component (a), the curable component (b) and the curable polymer component (ab). 2 to 10 parts by mass, more preferably 0.3 to 5 parts by mass. If the content of the silane coupling agent is less than 0.1 parts by mass, the above effect may not be obtained, and if it exceeds 20 parts by mass, it may cause outgassing.

(F) In addition to the above, various additives may be added to the film for forming a general-purpose additive protective film as necessary. Examples of various additives include leveling agents, plasticizers, antistatic agents, antioxidants, ion scavengers, gettering agents, chain transfer agents, and the like.

The protective film-forming film may be a single composition film or a laminated film of two or more films having different compositions. When the film is composed of two or more kinds of films, for example, the film to be bonded to the workpiece is blended with a relatively large amount of components capable of improving the adhesiveness of the film, and the other film (the film in contact with the second adhesive layer) The amount of the curable component may be increased.

The thickness of the protective film-forming film is not particularly limited, but is preferably 3 to 300 μm, more preferably 5 to 250 μm, and particularly preferably 7 to 200 μm.

FIG. 1 shows the structure of the composite sheet for forming a protective film of the present invention comprising the above layers. As shown in FIG. 1, a protective film-forming composite sheet 10 is formed on a first adhesive layer 2 of an adhesive sheet 5 including a substrate 1 and a first adhesive layer 2 as constituent layers. Is provided via the second pressure-sensitive adhesive layer 3. The protective film-forming film 4 is formed on the second pressure-sensitive adhesive layer 3 so as to be peelable. The protective film-forming film 4 is not particularly limited as long as it is substantially the same shape as the workpiece or can completely include the shape of the workpiece, and may be the same shape as the second pressure-sensitive adhesive layer 3 as shown in FIG. .

The shape of the composite sheet for forming a protective film is not limited to a single sheet, but may be a long strip or roll it up.

Before using the protective film-forming composite sheet, a release sheet is laminated on the protective film-forming film in order to protect the protective film-forming film, the first pressure-sensitive adhesive layer, and the second pressure-sensitive adhesive layer. May be. As a release sheet, the film illustrated as a base material mentioned above can be used. The surface tension of the surface of the release sheet that contacts the protective film-forming film is preferably 40 mN / m or less, more preferably 37 mN / m or less, and particularly preferably 35 mN / m or less. The lower limit is usually about 25 mN / m. Such a release sheet having a relatively low surface tension can be obtained by appropriately selecting the material, and can also be obtained by applying a release agent to the surface of the release sheet and performing a release treatment. .

As the release agent used for the release treatment, alkyd, silicone, fluorine, unsaturated polyester, polyolefin, wax, and the like are used. In particular, alkyd, silicone, and fluorine release agents are heat resistant. This is preferable.

In order to release the surface of a film or the like as a substrate of a release sheet using the above release agent, the release agent can be used without any solvent, or can be diluted or emulsified in a solvent to obtain a gravure coater, Mayer bar coater, air knife coater. The release sheet may be applied by a roll coater or the like, and the release sheet on which the release agent is applied is subjected to room temperature or heating, or cured by an electron beam to form a release agent layer.

Further, the surface tension of the release sheet may be adjusted by laminating films by wet lamination, dry lamination, hot melt lamination, melt extrusion lamination, coextrusion processing, or the like. That is, a film in which the surface tension of at least one surface is within a preferable range as the surface in contact with the protective film-forming film of the release sheet described above is such that the surface is in contact with the protective film-forming film. Alternatively, a laminate laminated with another film may be manufactured and used as a release sheet.

According to the protective film-forming composite sheet having the configuration shown in FIG. 1, the protective film-forming composite sheet is bonded to the jig by the sufficient adhesiveness of the first pressure-sensitive adhesive layer in the region surrounding the protective film-forming film. be able to. At the same time, the adhesiveness at the interface between the second pressure-sensitive adhesive layer and the first pressure-sensitive adhesive layer can be controlled to facilitate the pickup of the chip with the protective film.
In addition, when the composite sheet for forming a protective film functions as a dicing sheet for supporting a workpiece in the dicing process, it is not necessary to dice by separately attaching a dicing sheet to the wafer with the film for forming the protective film in the dicing process. The manufacturing process of the semiconductor device can be simplified.

Further, in the composite sheet for forming a protective film, in the adhesive strength measurement test in which the adhesive sheet is peeled from the second adhesive layer, at least one of the first adhesive layer and the second adhesive layer is cohesively broken, or adhesive The force is preferably 0.8 N / 25 mm or more. When the adhesiveness between the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is relatively low, in the pressure-sensitive adhesive strength measurement test, the interface can be broken and the pressure-sensitive adhesive strength can be measured. When the adhesiveness between the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is remarkably high, one or both of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer cohesively break, and the adhesive force cannot be measured. The adhesive force measurement test is specifically described in the examples described later. The protective film-forming sheet has such characteristics, and since the adhesiveness between the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is large, the effect of the present invention is further improved. For example, the size is relatively large. Even when the composite sheet for forming a protective film of the present invention is used in a process for obtaining a chip, undesired peeling of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer can be prevented. In the protective sheet-forming composite sheet, in the adhesive force measurement test in which the adhesive sheet is peeled from the second adhesive layer, at least one of the first adhesive layer and the second adhesive layer is cohesively broken, or the adhesive force is More preferably, it is 1.2 N / 25 mm or more.

Such a protective film-forming film of the protective film-forming composite sheet can be used as a protective film of a chip. The protective film-forming film is affixed to the back surface of the face-down type chip and cured by an appropriate means to have a function of protecting the chip as an alternative to the sealing resin. Further, when the protective film-forming film is attached to the semiconductor wafer, the protective film has a function of reinforcing the wafer, so that damage to the wafer can be prevented.

[Method for producing composite sheet for forming protective film]
Next, although an example of the manufacturing method of the composite sheet for protective film formation shown in FIG. 1 is demonstrated, the composite sheet for protective film formation of this invention is not limited to what is obtained by such a manufacturing method. .

First, a 1st adhesive layer is formed in the surface of a base material, and an adhesive sheet is obtained. The method for providing the first pressure-sensitive adhesive layer on the surface of the substrate is not particularly limited, and the energy ray curable that constitutes the first pressure-sensitive adhesive layer so as to have a predetermined film thickness on the release sheet (first release sheet). A method of transferring a first coating formed by applying a composition containing a pressure-sensitive adhesive (first pressure-sensitive adhesive) to the surface of the substrate; a method of forming a first coating by directly applying the first pressure-sensitive adhesive to the surface of the substrate; Is mentioned. The 1st adhesive layer which consists of an adhesive which hardened the energy-beam curable adhesive by hardening | curing a 1st film by energy ray irradiation is obtained. Moreover, when energy beam irradiation is not performed on the first coating, the first coating becomes the first pressure-sensitive adhesive layer made of the energy beam-curable pressure-sensitive adhesive as it is.
Before laminating the first film of the pressure-sensitive adhesive sheet and the second film or second pressure-sensitive adhesive layer described below, the first film is cured by irradiating energy rays, and the first film is used as the first pressure-sensitive adhesive layer. Also good. In this case, curing may be limited to preliminary curing so that unreacted energy beam polymerizable groups remain in the first coating.

Examples of the energy rays include ultraviolet rays, and near ultraviolet rays including ultraviolet rays having a wavelength of about 200 to 380 nm may be used. The amount ultraviolet (light amount) is generally 50 ~ 500mJ / cm ² or so, preferably 100 ~ 450mJ / cm ^2, more preferably 200 ~ 400mJ / cm ^2. The ultraviolet illumination is usually 50 ~ 500mW / cm ² or so, preferably 100 ~ 450mW / cm ^2, more preferably 200 ~ 400mW / cm ^2. There is no restriction | limiting in particular as an ultraviolet-ray source, For example, a high pressure mercury lamp, a metal halide lamp, a light emitting diode etc. are used. In the following, when ultraviolet rays are used as the energy rays to be irradiated, an appropriate condition may be similarly selected from such a range.
As a release sheet, the film illustrated as a base material mentioned above can be used.

Moreover, the composition (2nd adhesive) containing the energy-beam curable adhesive which comprises a 2nd adhesive layer is apply | coated on another peeling sheet (2nd peeling sheet), and a film (2nd film) is applied. Form. Next, another release sheet (third release sheet) is laminated on the second coating to obtain a laminate of second release sheet / second coating / third release sheet. Then, by irradiating with energy rays, the second film is cured, and a second pressure-sensitive adhesive layer sandwiched between the second release sheet and the third release sheet is obtained.
It should be noted that the second coating is not irradiated with energy rays, or the curing is limited to preliminary curing so that unreacted energy beam polymerizable groups remain in the second coating, and the first coating or the first pressure-sensitive adhesive layer. After the lamination, the second coating may be cured to form a second pressure-sensitive adhesive layer.

Also, a protective film-forming composition is applied on another release sheet (fourth release sheet) to form a protective film-forming film. Next, another release sheet (fifth release sheet) is laminated on the protective film-forming film to obtain a laminate of fourth release sheet / protective film-forming film / fifth release sheet.

Next, the third release sheet is laminated from the laminate of the second release sheet / second pressure-sensitive adhesive layer / third release sheet, and the fourth release sheet is laminated from the laminate of fourth release sheet / protective film forming film / fifth release sheet. The second pressure-sensitive adhesive layer and the protective film-forming film are laminated while removing the film to obtain a laminate of second release sheet / second pressure-sensitive adhesive layer / protective film-forming film / fifth release sheet. Next, the second pressure-sensitive adhesive layer and the protective film-forming film are cut into a shape that can substantially include the shape of the work affixed to the protective film-forming film or the shape of the work, and the remaining portion is removed. . When the laminate of the second release sheet / second pressure-sensitive adhesive layer / protective film forming film / fifth release sheet is a long belt-like body, the fifth release sheet can be left without being cut. A laminated body of a plurality of second release sheets / second pressure-sensitive adhesive layers / protective film forming films continuously held by the fifth release sheet can be obtained.

And when the 1st exfoliation sheet is laminated on the 1st coat or the 1st adhesive layer, the 1st exfoliation sheet, the 2nd exfoliation sheet / the 2nd adhesive layer / the film for protective film formation / the 1st While peeling the second release sheet of the laminate composed of 5 release sheets, the first film or the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are laminated, and the base material / the first film or the first pressure-sensitive adhesive layer / A laminate comprising the second pressure-sensitive adhesive layer / the protective film-forming film / the fifth release sheet is obtained.
When the second coating is not irradiated with energy rays or when the second coating is preliminarily cured and laminated with the first coating or the first pressure-sensitive adhesive layer, energy rays are irradiated from the substrate side. The second coating is cured to form a second pressure-sensitive adhesive layer. When the first coating is not cured or is preliminarily cured, at this time, the first coating is irradiated with energy rays simultaneously with the second coating. It becomes the 1st adhesive layer which consists of an adhesive which hardened the.
Further, even when the second coating has already been cured, energy beam irradiation may be performed on the laminated body of the first coating and the second pressure-sensitive adhesive layer at this time for curing the first coating. The composite sheet for protective film formation of this invention is obtained by the above.

In particular, when the first pressure-sensitive adhesive layer in the composite sheet for forming a protective film is made of a pressure-sensitive adhesive obtained by curing an energy ray-curable pressure-sensitive adhesive, the energy is applied after laminating the first film and the second pressure-sensitive adhesive layer. By curing the first pressure-sensitive adhesive layer by irradiation with rays, the adhesiveness between the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer can be improved, so that the pickup property of the chip with protective film is excellent.

[Method of manufacturing chip with protective film]
Next, the manufacturing method of the chip | tip with a protective film using the composite sheet for protective film formation of this invention is demonstrated.

In the method for manufacturing a chip with a protective film of the present invention, the following steps (1) to (3) are performed in this order.
Step (1): A step of attaching the protective film-forming film of the protective film-forming composite sheet to the workpiece,
Step (2): a step of heat-curing the protective film-forming film to obtain a protective film,
Step (3): A step of separating the protective film and the second pressure-sensitive adhesive layer.

The workpiece may be a silicon wafer or a compound semiconductor wafer such as gallium / arsenic. Examples of the work include various articles such as glass substrates, ceramic substrates, organic material substrates such as FPC substrates, and metal materials such as precision parts. Furthermore, the chip | tip which separated them may be sufficient.

In the following, as an example, a method for manufacturing a chip with a protective film using a silicon wafer as a workpiece will be described.
Formation of a circuit on the wafer surface can be performed by various methods including conventionally used methods such as an etching method and a lift-off method. Next, the opposite surface (back surface) of the circuit surface of the wafer is ground. The grinding method is not particularly limited, and grinding may be performed by a known means using a grinder or the like. At the time of back surface grinding, an adhesive sheet called a surface protection sheet is attached to the circuit surface in order to protect the circuit on the surface. In the back surface grinding, the circuit surface side (that is, the surface protection sheet side) of the wafer is fixed by a chuck table or the like, and the back surface side on which no circuit is formed is ground by a grinder. The thickness of the wafer after grinding is not particularly limited, but is usually about 50 to 500 μm.

After that, if necessary, the crushed layer generated during back grinding is removed. The crushed layer is removed by chemical etching, plasma etching, or the like.

Next, a protective film forming film of the protective film forming composite sheet is attached to the back surface of the wafer. A sticking method is not particularly limited.

Then, the protective film-forming film is cured by heating to form a protective film on the back surface of the wafer. As a result, a protective film made of a cured resin is formed on the back surface of the wafer, and the strength is improved as compared with the case of the wafer alone, so that damage during handling of the thinned wafer can be reduced. In addition, the thickness uniformity of the protective film is excellent as compared with a coating method in which a coating solution for a resin film is directly applied to the back surface of the wafer.

Next, the wafer and the protective film are diced for each circuit formed on the wafer surface (dicing process). Dicing is performed so as to cut both the wafer and the protective film. The composite sheet for forming a protective film of the present invention can serve as a dicing sheet that supports a wafer. In the dicing process, the outer peripheral portion of the protective film forming composite sheet is bonded to another jig such as a ring frame, so that the protective film forming composite sheet attached to the semiconductor wafer is fixed to the apparatus, and dicing is performed. Is called. Dicing of the semiconductor wafer on the composite sheet for forming a protective film is performed in the same manner as a conventional method using a known dicing sheet. In addition, a dicing process can also be performed before the process of heat-hardening the film for protective film formation and obtaining a protective film.

By picking up the chip diced in this way (chip with protective film) by a general-purpose means such as a collet, the protective film and the second pressure-sensitive adhesive layer can be separated to obtain a chip with a protective film. According to the composite sheet for forming a protective film of the present invention, a protective film-forming film is formed by forming a pressure-sensitive adhesive layer using a specific pressure-sensitive adhesive and setting the tensile elastic modulus of the second pressure-sensitive adhesive layer to a specific range. It is easy to peel off the protective film obtained by curing from the second pressure-sensitive adhesive layer. In addition, problems such as peeling between the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer at the time of pickup due to a decrease in adhesiveness between the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer can be prevented. .

Next, laser printing can be performed on the protective film. Laser printing is performed by a laser marking method, and the surface of the protective film is scraped off by laser light irradiation to mark a product number or the like on the protective film.

Finally, a semiconductor device can be manufactured by mounting a chip with a protective film on a predetermined base in a face-down manner. Further, a semiconductor device can be manufactured by adhering a semiconductor chip having a protective film on the back surface to another member (on the chip mounting portion) such as a die pad portion or another semiconductor chip.

Hereinafter, the present invention will be described by way of examples, but the present invention is not limited to these examples. In the following Examples or Comparative Examples, <Pickup Property>, <Second Adhesive Layer Transfer>, <Tensile Elastic Modulus>, and <Adhesive Strength Measurement Test> were measured and evaluated as follows.

<Pickup property>
Use a tape mounter (Adwill RAD2700, manufactured by Lintec) to attach the protective film-forming film of the protective film-forming composite sheet to the polished surface of a silicon wafer (200 mm diameter, 200 μm thick) that has been back-ground with a # 2000 grindstone. And fixed to a ring frame for wafer dicing.
Next, the protective film-forming composite sheet and the wafer were placed in an environment at 130 ° C. for 2 hours to cure the protective film-forming film.
Thereafter, the silicon wafer was diced using a dicing apparatus (DFD651 manufactured by DISCO) to obtain a 5 mm × 5 mm chip. The amount of cutting during dicing was such that the substrate was cut by 15 μm, and the cutting speed was 40 mm / min. Moreover, as a dicing blade, 27HECC made by DISCO was used, and the rotation speed of the blade was 35,000 rpm.
It was confirmed whether or not the obtained chip could be picked up using a pickup device (BESTEM DO2 manufactured by Canon Machinery).
Specifically, all the pins were pushed up by 1000 μm with the push-up pins (five), and then picked up by further pushing up by 400 μm with the center pin (one). The thrusting speed was 10 mm / second and 20 mm / second.
The case where pick-up was possible at a thrust speed of 20 mm / sec was evaluated as “A”, the case where pick-up was possible at 10 mm / sec was “B”, and the case where pick-up was not possible at any speed was evaluated as “C”.

<Transfer of second adhesive layer>
The back surface (protective film surface) of the chip with protective film that could be picked up in the evaluation of the pickup property was confirmed, and it was confirmed whether or not the second pressure-sensitive adhesive layer was transferred. As a confirmation method, the thickness of the chip with protective film was measured and confirmed to be the expected thickness. Moreover, when the cellophane tape made from Nichiban was affixed on the protective film surface and it peeled, it confirmed that the 2nd adhesive layer did not adhere to the cellophane tape.
The case where no transfer failure occurred was evaluated as “A”, and the case where transfer failure occurred was evaluated as “B”.

<Tensile modulus>
The tensile elastic modulus of the second pressure-sensitive adhesive layer was measured using a viscoelasticity measuring apparatus (manufactured by TA Instruments, DMA Q800).
First, the 2nd adhesive layer before ultraviolet curing was laminated | stacked, and the 200-micrometer-thick laminated body was obtained. Thereafter, a sample irradiated with ultraviolet rays using an ultraviolet irradiation device (RAD-2000 manufactured by Lintec Corporation) under irradiation conditions of an illuminance of 230 mW / cm ² and a light amount of 190 mJ / cm ² (main wavelength 365 nm) was used as a sample.
Measurement conditions were set so that the measurement part of the sample had a length of 20 mm and a width of 4 mm, measurement was performed at an amplitude of 16 μm and a measurement temperature range of −40 to 150 ° C., and a tensile elastic modulus at a frequency of 11 Hz at 25 ° C. was measured. Value.

<Adhesion test>
The protective film-forming film was removed from the protective film-forming sheet and cut into a width of 25 mm to prepare a sample. When the exposed surface of the second pressure-sensitive adhesive layer is fixed to a flat plate and the pressure-sensitive adhesive sheet is peeled off at an angle of 180 ° from the second pressure-sensitive adhesive layer at a speed of 300 mm / min in an environment of 23 ° C. and 50% relative humidity The adhesive strength of was measured.

Production of protective film-forming film Each component constituting the protective film-forming film and its blending amount are shown below (component / blending amount). The compounding quantity of each component shows the mass part of solid content conversion, and solid content means all components other than a solvent in this invention.

[Composition for forming protective film]
(A1) Acrylic polymer: acrylic polymer comprising 55 parts by mass of n-butyl acrylate, 10 parts by mass of methyl acrylate, 20 parts by mass of glycidyl methacrylate, and 15 parts by mass of 2-hydroxyethyl acrylate (weight average molecular weight: 900,000) , Glass transition temperature: -28 ° C.) / 20 parts by mass (b1) thermosetting component:
(B11-1) Bisphenol A type epoxy resin (epoxy equivalent 180 to 200 g / eq) / 20 parts by mass (b11-2) Dicyclopentadiene type epoxy resin (Epicron HP-7200HH manufactured by Dainippon Ink & Chemicals, Inc.) / 10 parts by weight (b12) Dicyandiamide (Adekaha Donor 3636AS manufactured by Asahi Denka) /0.5 parts by weight (b13) Curing accelerator: 2-phenyl-4,5-dihydroxymethylimidazole (Cureazole 2PHZ manufactured by Shikoku Chemicals Co., Ltd.) ) /0.5 parts by mass (c) Inorganic filler: Silica filler (fused quartz filler (average particle size 8 μm)) / 60 parts by mass (d) Colorant: Black pigment (carbon black (# MA650, manufactured by Mitsubishi Chemical Corporation, average) Particle size 28 nm)) / 2 parts by mass (e) Coupling agent: Silane coupling agent (Nihon Unica Company Ltd. A-1110) /0.2 parts by

A protective film-forming composition was applied to a release sheet (SP-PET3811 manufactured by Lintec Co., Ltd., thickness 38 μm) so that the coating amount after drying was 42 g / m ² and dried at 110 ° C. for 2 minutes to form a protective film Was formed, and another release sheet (SP-PET3811 manufactured by Lintec Corporation, thickness 38 μm) was laminated on the protective film-forming film to obtain a laminate of release sheet / protective film-forming film / release sheet. .

(Example 1)
Preparation of pressure-sensitive adhesive sheet Acrylic polymer (2-ethylhexyl acrylate / butyl acrylate / hydroxyethyl acrylate = 35/60/5 (mass ratio), weight average molecular weight: 600,000) and 60% equivalent of methacryloyloxyethyl isocyanate (acrylic) An energy beam curable polymer was prepared by reacting 4 parts by mass with respect to 100 parts by mass of the polymer.

To 100 parts by mass of this energy beam curable polymer, 3.0 parts by mass of a photopolymerization initiator (Irgacure (registered trademark) 184, manufactured by Ciba Specialty Chemicals) and an isocyanate compound (D-, manufactured by Mitsui Takeda Chemical Co., Ltd.) as a crosslinking agent. 110N) 10 parts by mass (all blending ratios in terms of solid content) were mixed and diluted with toluene / ethyl acetate (120/70 parts) to obtain an adhesive (first adhesive).

The first adhesive was applied to a release sheet (SP-PET3811 manufactured by Lintec Corporation, thickness 38 μm) so that the coating amount after drying was 5 g / m ² and dried at 100 ° C. for 2 minutes to form the first film. Then, as a base material, it laminated | stacked on the corona treatment surface of the polypropylene film (thickness of 80 micrometers) which gave the corona treatment to one side, and obtained the laminated body of the peeling sheet / 1st film | membrane / base material.

Preparation of second adhesive layer Acrylic polymer (2-ethylhexyl acrylate / vinyl acetate / hydroxyethyl acrylate = 40/40/20 (mass ratio), weight average molecular weight: 500,000) 80% equivalent of methacryloyloxyethyl isocyanate (21.4 parts by mass with respect to 100 parts by mass of the acrylic polymer) A reacted energy ray-curable polymer was produced.

To 100 parts by mass of this energy ray-curable polymer, 3.0 parts by mass of a photopolymerization initiator (Irgacure (registered trademark) 184 manufactured by Ciba Specialty Chemicals) and an isocyanate compound (BHS- manufactured by Toyo Ink Manufacturing Co., Ltd.) as a crosslinking agent 8515) 0.5 parts by mass were blended (all blending ratios in terms of solid content) and diluted with methyl ethyl ketone to obtain a pressure-sensitive adhesive (second pressure-sensitive adhesive).

The second adhesive was applied to a release sheet (SP-PET3811 manufactured by Lintec Corporation, thickness 38 μm) so that the coating amount after drying was 10 g / m ^2, and dried at 100 ° C. for 2 minutes to form a second film. After that, a release sheet (SP-PET3811 manufactured by Lintec Corporation, thickness 38 μm) was laminated to obtain a release sheet / second coating / release sheet laminate. Then, using a UV irradiation device (RAD-2000 manufactured by Lintec), the second coating is cured by irradiating with UV light under irradiation conditions of illuminance of 230 mW / cm ² and light amount of 190 mJ / cm ² (main wavelength 365 nm), A second pressure-sensitive adhesive layer was obtained.

Production of Composite Sheet for Forming Protective Film One release from the laminate of release sheet / film for protective film / release sheet obtained above and the laminate of release sheet / second adhesive layer / release sheet While peeling off the sheet, the protective film-forming film and the second pressure-sensitive adhesive layer were heat-laminated (60 ° C., 1 m / min).
Subsequently, the release sheet laminated on the second pressure-sensitive adhesive layer was removed while the second pressure-sensitive adhesive layer and the protective film-forming film were punched into a circular shape (220 mm diameter). Thereby, the laminated body by which the same circular protective film formation layer and the 2nd adhesive layer were laminated | stacked in this order on the peeling sheet was obtained. Then, while peeling the release sheet of the release sheet / first coating / substrate laminate, the second pressure-sensitive adhesive layer and the first coating are laminated, and the release sheet / protective film forming film / second pressure-sensitive adhesive layer / A laminate of the first film / substrate was obtained.
Then, using a UV irradiation device (RAD-3600 manufactured by Lintec Corporation), UV irradiation was performed from the substrate side under irradiation conditions of an illuminance of 230 mW / cm ² and a light amount of 190 mJ / cm ² (main wavelength 365 nm), and the first coating was applied. It hardened | cured and it was set as the 1st adhesive layer and the composite sheet for protective film formation which the peeling sheet laminated | stacked on the film for protective film formation was obtained. Each evaluation result is shown in Table 1.

(Example 2)
As an energy ray curable polymer in the production of an adhesive sheet, an acrylic polymer (butyl acrylate / methyl methacrylate / hydroxyethyl acrylate = 74/20/6 (mass ratio), weight average molecular weight: 350,000), methacryloyloxy An energy ray-curable polymer obtained by reacting 50% equivalent of ethyl isocyanate (3 parts by mass with respect to 100 parts by mass of the acrylic polymer) was used.
In addition, an isocyanate compound (BHS-8515 manufactured by Toyo Ink Manufacturing Co., Ltd.) was used as a crosslinking agent in the production of the pressure-sensitive adhesive sheet, and 0.5 part by mass was blended with respect to 100 parts by mass of the energy ray curable polymer.

Except for the above, a protective sheet-forming composite sheet was obtained in the same manner as in Example 1. Each evaluation result is shown in Table 1.

(Example 3)
In the production of the protective film-forming composite sheet, a protective film-forming composite sheet was obtained in the same manner as in Example 2 except that ultraviolet irradiation was not performed. That is, in Example 3, the uncured first film was used as the first pressure-sensitive adhesive layer. Each evaluation result is shown in Table 1.

Example 4
As an energy ray-curable polymer in the production of the second pressure-sensitive adhesive layer, an acrylic polymer (2-ethylhexyl acrylate / vinyl acetate / hydroxyethyl acrylate = 60/20/20 (mass ratio), weight average molecular weight: 350,000) An energy ray-curable polymer obtained by reacting 80% equivalent of methacryloyloxyethyl isocyanate (21 parts by mass with respect to 100 parts by mass of the acrylic polymer) was used.

A composite sheet for forming a protective film was obtained in the same manner as Example 2 except for the above. Each evaluation result is shown in Table 1.

(Comparative Example 1)
Instead of the energy ray curable polymer in the production of the pressure-sensitive adhesive sheet, an acrylic polymer (2-ethylhexyl acrylate / butyl acrylate / hydroxyethyl acrylate = 35/60/5 (mass ratio), weight average molecular weight: 500,000) was used. Using.
Moreover, the photoinitiator in preparation of an adhesive sheet was not mix | blended.
Furthermore, ultraviolet rays were not irradiated in the production of the protective sheet-forming composite sheet.

Except for the above, a protective sheet-forming composite sheet was obtained in the same manner as in Example 1. Each evaluation result is shown in Table 1.

(Comparative Example 2)
As an energy ray-curable polymer in the production of the second pressure-sensitive adhesive layer, an acrylic polymer (2-ethylhexyl acrylate / hydroxyethyl acrylate = 80/20 (mass ratio), weight average molecular weight: 350,000) and methacryloyloxyethyl isocyanate Was used as an energy ray curable polymer in which 80% equivalent (21 parts by mass with respect to 100 parts by mass of the acrylic polymer) was reacted.

Other than the above, a composite sheet for forming a protective film was obtained in the same manner as in Comparative Example 1. Each evaluation result is shown in Table 1.

(Comparative Example 3)
As an energy ray curable polymer in the production of the second pressure-sensitive adhesive layer, an acrylic polymer (2-ethylhexyl acrylate / vinyl acetate / hydroxyethyl acrylate = 60/20/20 (mass ratio), weight average molecular weight: about 350,000 ) Was used for the reaction with 80% equivalent of methacryloyloxyethyl isocyanate (21 parts by mass with respect to 100 parts by mass of the acrylic polymer).

Other than the above, a composite sheet for forming a protective film was obtained in the same manner as in Comparative Example 1. Each evaluation result is shown in Table 1.

In the adhesive strength, “cohesive failure” indicates that at least one of the first adhesive layer and the second adhesive layer has undergone cohesive failure.

1: Base material 2: First pressure-sensitive adhesive layer 3: Second pressure-sensitive adhesive layer 4: Film for forming a protective film 5: Pressure-sensitive adhesive sheet 10: Composite sheet for forming a protective film

Claims (7)

1. A protective film-forming composite sheet in which a protective film-forming film is provided on a first pressure-sensitive adhesive layer of a pressure-sensitive adhesive sheet comprising a base material and a first pressure-sensitive adhesive layer as constituent layers, via a second pressure-sensitive adhesive layer, ,
   The shape of the second pressure-sensitive adhesive layer in plan view is a shape included in the shape of the pressure-sensitive adhesive sheet in plan view,
   The first pressure-sensitive adhesive layer is composed of an energy beam-curable pressure-sensitive adhesive or an energy beam-cured pressure-sensitive adhesive,
   The second pressure-sensitive adhesive layer is made of a pressure-sensitive adhesive obtained by curing an energy ray-curable pressure-sensitive adhesive,
   A composite sheet for forming a protective film, wherein the second adhesive layer has a tensile elastic modulus at 25 ° C. of 200 to 2000 MPa.
2. The composite sheet for forming a protective film according to claim 1, wherein the second pressure-sensitive adhesive layer has a tensile elastic modulus at 25 ° C of 500 to 2000 MPa.
3. The composite sheet for forming a protective film according to claim 1 or 2, wherein the film for forming a protective film is thermosetting.
4. The composite sheet for forming a protective film according to any one of claims 1 to 3, wherein the base material comprises a film containing one or more layers of polypropylene film.
5. In an adhesive strength measurement test in which the adhesive sheet is peeled from the second adhesive layer, at least one of the first adhesive layer and the second adhesive layer is cohesively broken, or the adhesive strength is 0.8 N / 25 mm or more. The composite sheet for forming a protective film according to any one of claims 1 to 4.
6. A method for producing the composite sheet for forming a protective film according to any one of claims 1 to 5,
   A step of laminating a second pressure-sensitive adhesive layer on the first pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet,
   The manufacturing method of the composite sheet for protective film formation which has the process of hardening a 1st adhesive layer, after laminating | stacking a 1st adhesive layer and a 2nd adhesive layer.
7. A method for producing a chip with a protective film, wherein the following steps (1) to (3) are carried out in this order;
   Step (1): A step of attaching the protective film-forming film of the protective film-forming composite sheet according to any one of claims 1 to 5 to a workpiece,
   Step (2): a step of heat-curing the protective film-forming film to obtain a protective film,
   Step (3): A step of separating the protective film and the second pressure-sensitive adhesive layer.
   

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