FIG. 1). The release film 2 is also called a carrier film. The release film 2 supports the adhesive film 3 by being stuck to the adhesive film 3. The release film 2 may be a resin film formed of polyethylene terephthalate (PET), polyethylene, polypropylene, or the like. The surface (principal surface 2a) of the release film 2 where the adhesive film 3 is provided may be subjected to a mold release treatment, a plasma treatment, or the like. The length in the longitudinal direction (X-direction shown in part (a) of FIG. 1) of the release film 2 may be, for example, 1 to 400 m. The length in the transverse direction (Y-direction shown in part (a) of FIG. 1) of the release film 2 may be, for example, 5 to 300 mm. The thickness of the release film 2 may be, for example, 5 to 200 μm.

Meanwhile, when the adhesive film 3 is stuck to an adhesive surface (not shown in the drawing) of a target of adhesion with high precision, it is necessary to specify the position of the adhesive film 3 in the adhesive sheet 1A. Thus, it is conceivable to detect the position of the adhesive film 3 in the adhesive sheet 1A using an image pickup device. However, when considering that the adhesive film 3 is stuck to the adhesive surface afterwards, it is preferable that the image pick-up device is disposed on the release film 2 side. Thus, the release film 2 may have optical transparency so that the position of the adhesive film 3 can be detected from the release film 2 side using an image pick-up device. In this case, the transmittance of the release film 2 can be set to 15% or higher and 100% or lower, preferably set to 15% or higher and 99% or lower, and more preferably set to 16% or higher and 98% or lower. The transmittance of the release film 2 is obtained by setting the release film cut into a square having a size of 50 mm×50 mm on a haze meter (for example, NDH-5000 manufactured by NIPPON DENSHOKU INDUSTRIES CO., LTD.) and measuring the total light transmittance.

The haze value of the release film 2 can be set to 3% or higher and 100% or lower, preferably set to 3% or higher and 99% or lower, and more preferably 4% or higher and 99% or lower. The haze value of the release film 2 is obtained by setting the release film cut into a square having a size of 50 mm×50 mm on a haze meter (for example, NDH-5000 manufactured by NIPPON DENSHOKU INDUSTRIES CO., LTD.) and measuring the haze value.

The release film 2 may have an alignment mark so that the position of the adhesive film 3 can be detected from the release film 2 side using an image pick-up device.

The release film 2 has a through-hole 4 that penetrates in the thickness direction (Z-direction shown in part (b) of FIG. 1 (direction orthogonally intersecting the X-direction and the Y-direction)). The through-hole 4 is formed such that when the adhesive sheet 1A is stuck to an adherend (an electronic component or the like), a protruding part formed on the adhesive surface of the adherend can be exposed through the through-hole 4. The opening shape of the through-hole 4 in FIG. 1 is a rectangular shape; however, the opening shape may be a shape corresponding to the outer shape (planar shape) of the protruding part formed on the adhesive surface of the adherend, may be a regular shape such as a polygonal shape, a circular shape, or an elliptical shape, or may be an irregular shape. In addition, the size and the number of the through-holes 4 can also be changed as appropriate according to the size and the number of the protruding parts formed on the adhesive surface of the adherend.

Regarding the adhesive film 3, a plurality of them are arranged along the longitudinal direction (X-direction) of the release film 2. The plurality of the adhesive films 3 are separated apart from each other in the longitudinal direction of the release film 2. The interval between adjacent adhesive films 3, 3 (shortest distance in the X-direction) may be 0.1 mm or more, 0.5 mm or more, 0.8 mm or more, 1 mm or more, or 3 mm or more, and may be 5 mm or less, 8 mm or less, 10 mm or less, or 30 mm or less. All the adhesive films 3 may be arranged at constant intervals, or the adhesive films 3 may be arranged at different intervals.

The adhesive film 3 is formed around an opening 4a such that the opening 4a on the principal surface 2a side of the through-hole 4 is exposed when viewed from the thickness direction (Z-direction). As a result, when the adhesive sheet 1A is stuck to an adherend (electronic component or the like), a protruding part formed on the adhesive surface of the adherend can be exposed through the through-hole 4 of the release film 2, and after peeling of the release film 2, the adhesive film 3 can be provided around the protruding part without having the adhesive attached to the protruding part.

The length in the longitudinal direction (X-direction) of the release film 2 of the adhesive film 3 may be, for example, 0.1 to 20 mm. The length in the transverse direction (Y-direction) of the release film 2 of the adhesive film 3 is smaller than the length in the transverse direction of the release film 2 and may be, for example, 5 to 80 mm. The length in the transverse direction (Y-direction) of the release film 2 of the adhesive film 3 may be the same as the length in the transverse direction (Y-direction) of the release film 2. The thickness of the adhesive film 3 may be, for example, 0.001 to 10 mm.

The adhesive constituting the adhesive film 3 is, for example, a conductive adhesive containing an adhesive component and conductive particles. The conductive particles are, for example, dispersed in the adhesive component such that the adhesive film 3 has anisotropic conductivity.

The adhesive component may be, for example, a thermosetting or photocurable adhesive component. The thermosetting or photocurable adhesive component may include, for example, a curable resin such as a cationically polymerizable compound, an anionically polymerizable compound, or a radically polymerizable compound. The cationically polymerizable compound and the anionically polymerizable compound may include an epoxy resin, a vinyl ether resin, or an oxetane resin. The adhesive component contains a curable resin and a curing agent and may further contain a thermoplastic resin, a coupling agent, a filler, and the like as necessary.

Examples of the epoxy resin include a bisphenol A type epoxy resin, a bisphenol S type epoxy resin, a bisphenol F type epoxy resin, a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, a bisphenol A novolac type epoxy resin, a bisphenol F novolac type epoxy resin, a tetramethyl bisphenol A type epoxy resin, 3′,4′-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate (bi-7-oxabicyclo[4,1,0]heptane), 3,4-epoxycyclohexylmethyl (meth)acrylate, (3,3′,4,4′-diepoxy)bicyclohexyl, dicyclopentadiene dimethanol diglycidyl ether, xylene-novolac type glycidyl ether, and a biphenyl type epoxy resin. The epoxy compound may include at least one selected from the group consisting of a bisphenol A type epoxy resin, a tetramethyl bisphenol A type epoxy resin, dicyclopentadiene dimethanol diglycidyl ether, xylene-novolac type glycidyl ether, and an alicyclic epoxy resin. The epoxy compound may include a glycidyl ether-based compound.

Regarding the oxetane resin, any resin having one or more oxetane ring structures in the molecule can be used without particular limitation.

The curing agent is not particularly limited as long as it can cure a cationically polymerizable compound or an anionically polymerizable compound, and examples thereof include an anionically polymerizable catalyst type curing agent, a cationically polymerizable catalyst type curing agent, and a polyaddition type curing agent. The content of the curing agent may be 0.05 to 20 parts by mass with respect to 100 parts by mass of the total amount of the curable resin and the thermoplastic resin that is blended as necessary.

The anionically or cationically polymerizable catalyst type curing agent may be, for example, an imidazole-based agent, a hydrazide-based agent, a boron trifluoride-amine complex, an onium salt (an aromatic sulfonium salt, an aromatic diazonium salt, an aliphatic sulfonium salt, a pyridium salt, or the like), amineimide, diaminomaleonitrile, melamine and a derivative thereof, a salt of polyamine, or dicyandiamide, or may be these of modification products. Examples of the polyaddition type curing agent include polyamine, polymercaptan, polyphenol, and acid anhydride.

The radically polymerizable compound may be, for example, a compound having a functional group that is polymerized by a radical. The radically polymerizable compound may be, for example, an acrylate (also including corresponding methacrylate; hereinafter, the same) compound, a (meth)acrylic acid compound, an acryloxy (also including corresponding methacryloxy; hereinafter, the same) compound, a maleimide compound, a citraconimide resin, or a nadimide resin. These may be used in the form of either a monomer or an oligomer, or a monomer and an oligomer may be used in combination. Regarding the radically polymerizable compounds, one kind thereof may be used alone, or two or more kinds thereof may be used in combination.

Examples of the acrylate compound include methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, 2-hydroxy-1,3-diacryloxypropane, 2,2-bis[4-(acryloxymethoxy)phenyl]propane, 2,2-bis[4-(acryloxypolyethoxy)phenyl]propane, dicyclopentenyl acrylate, tricyclodecanyl acrylate, tris(acryloyloxyethyl) isocyanurate, urethane acrylate, and phosphoric acid ester diacrylate.

The radical polymerization initiator may be, for example, a compound that is decomposed by heating or irradiation with light to generate free radicals. The radical polymerization initiator may be, for example, a peroxide compound or an azo-based compound. The radical polymerization initiator is preferably diacyl peroxide, peroxydicarbonate, peroxy ester, peroxy ketal, dialkyl peroxide, hydroperoxide, and silyl peroxide. The content of the radical polymerization initiator may be 0.1 to 10 parts by mass with respect to 100 parts by mass of the total amount of the radically polymerizable compound and a thermoplastic resin that is blended as necessary.

The thermoplastic resin that is blended with the thermosetting or photocurable adhesive component as necessary includes a phenoxy resin, a polyvinyl formal resin, a polystyrene resin, a polyvinyl butyral resin, a polyester resin, a polyamide resin, a xylene resin, a polyurethane resin, a polyester urethane resin, a phenol resin, and a terpene phenol resin.

In a case where the thermoplastic resin is blended with a thermosetting adhesive component, the content of the thermoplastic resin may be 5 to 80 parts by mass with respect to 100 parts by mass of the total amount of the thermosetting resin and the thermoplastic resin. In a case where the thermoplastic resin is blended with a photocurable (radical-curable) adhesive component, the content of the thermoplastic resin may be 5 to 80 parts by mass with respect to 100 parts by mass of the total amount of the radically polymerizable compound and the thermoplastic resin.

The content of the adhesive component may be 75 to 98% by volume based on the total volume of the adhesive.

Regarding the conductive particles, for example, metal particles of Au, Ag, Ni, Cu, Pd, and solder, and carbon particles are used. In addition, the conductive particles may be particles obtained by coating the surface of transition metals such as Ni and Cu with noble metals such as Au and Pd. Furthermore, the conductive particles may be coated conductive particles having a non-conductive core formed of a non-conductive material such as glass, a ceramic, or a resin (an acrylic resin, a styrene resin, silicone, or the like) and a conductive layer coating the surface of the core. In this case, the conductive layer may be formed of, for example, gold, silver, copper, nickel, palladium, or an alloy of these. The conductive particles may also be particles having an outermost layer composed of a noble metal, particles using heat-melting metal particles, or the like. The average particle size of the conductive particles may be, for example, 1 to 50 μm. The average particle size is measured by using a particle size distribution analyzer (Microtrac (product name, Nikkiso Co., Ltd.)) using a laser diffraction and scattering method. The conductive particles may have, for example, an approximately spherical shape.

The conductive particles may have an anisotropic shape. The term “anisotropic shape” according to the present specification refers to shape anisotropy and implies that the shape is not an approximately point-symmetric (approximately isotropic) shape (for example, a spherical shape). The conductive particles having an anisotropic shape may have a dendrite shape (also referred to as a dendritic shape) or a flake shape. The conductive particles having an anisotropic shape may be formed of a metal such as copper or silver or may be, for example, silver-coated copper particles obtained by coating copper particles with silver. Regarding the conductive particles, one kind thereof may be used alone, or two or more kinds thereof may be used in combination.

The content of the conductive particles in the adhesive may be 2 to 70% by volume based on the total volume of the adhesive. The adhesive does not have to contain conductive particles.

The adhesive sheet 1A can be applied to various adhesive sheets for semiconductor device production. Specifically, for example, the adhesive sheet 1A can be used in use applications for connection of circuit members (for example, connection between a semiconductor chip and a wiring circuit board or another semiconductor chip).

In the adhesive sheet 1A described above, since the release film 2 has a through-hole 4, and the adhesive film 3 is formed around the opening 4a when viewed in a plan view, even in a case where the adherend has a protruding part on the adhesive surface, the adhesive film 3 can be stuck to the periphery of the protruding part without attaching the adhesive to the protruding part, by positioning the adhesive film 3 such that the protruding part and the through-hole 4 are superposed when viewed in a plan view. In addition, since the shape of the adhesive film 3 can be arbitrarily set according to the shape of the adhesive surface of the adherend, the adhesive film 3 can be effectively utilized for various adhesive surfaces of adherends.

As described above, the adhesive sheet according to an embodiment has been described; however, the adhesive sheet of the present disclosure is not limited to the above-described embodiment.

For example, the adhesive sheet may further include a cover film on a surface of the adhesive film 3, the surface being on the opposite side of the release film 2. The cover film may have the same size and shape as the size and shape of the release film 2. The cover film may be provided only on the adhesive film 3.

In the above-described embodiment, a plurality of the adhesive films 3 are separated apart from each other in the longitudinal direction of the release film 2; however, the adhesive film 3 may be continuous in the longitudinal direction (X-direction) of the release film 2. Furthermore, in the above-described embodiment, the release film 2 is long, and a plurality of the adhesive films 3 are arranged along the longitudinal direction (X-direction) of the release film 2; however, one adhesive film may be formed on a principal surface of a release film having a rectangular outer shape.

Furthermore, in the above-described embodiment, the adhesive film 3 is disposed at the central part in the transverse direction (Y-direction) of the release film 2; however, a plurality of the adhesive films 3 may be disposed at any locations in the transverse direction (Y-direction) of the release film 2. The adhesive films 3 may be disposed at the ends in the transverse direction (Y-direction) of the release film 2. In addition, a plurality of the adhesive films 3 may be arranged in the transverse direction (Y-direction) of the release film 2.

In the above-described embodiment, the adhesive film 3 is formed continuously so as to surround the entire circumference of the opening 4a in the release film 2 when viewed from the thickness direction (Z-direction) of the release film 2; however, as is the case of the adhesive sheet 1B shown in part (a) and part (b) of FIG. 2, the adhesive film 3 may be formed so as to surround a portion of the opening 4a. In the present specification, even in a case where a portion of the opening 4a is surrounded by the adhesive film 3 in this way, when 5% or more of the entire circumference of the opening 4a is surrounded by the adhesive film 3, it is assumed that the adhesive film 3 is formed around the opening 4a.

Furthermore, in the above-described embodiment, the adhesive film 3 is formed such that the edges of the adhesive film 3 follow the edges of the opening 4a (that is, the edges of the adhesive film 3 and the edges of the opening 4a match); however, as is the case of the adhesive sheet 1C shown in part (a) and (b) of FIG. 3, the edges of the adhesive film 3 and the edges of the opening 4a do not have to match, and there may be regions where the adhesive film 3 does not exist in the area between the edges of the adhesive film 3 and the edges of the opening 4a. In the present specification, even in a case where the edges of the opening 4a and the edges of the adhesive film 3 do not match in this way, when the distance (shortest distance when viewed in a plan view) between the opening 4a and the adhesive film 3 is 5 mm or less, it is assumed that the adhesive film 3 is formed around the opening 4a. Although not shown in the drawing, in the above-described embodiment in which the edges of the opening 4a do not match the edges of the adhesive film 3, a portion of the edges of the opening 4a may match the edges of the adhesive film 3. Furthermore, even in the above-described embodiment in which the edges of the opening 4a do not match the edges of the adhesive film 3, the adhesive film 3 may be formed so as to surround a portion of the opening 4a.

In the above-described embodiment, the release film 2 has a through-hole 4; however, as is the case of the adhesive sheet 1D shown in part (a) and (b) of FIG. 4, the release film 2 may have a notch part 30 in a part of the peripheral edge portion of the release film, instead of the through-hole 4 (or in addition to the through-hole 4). In this case, the adhesive film 3 is formed around the notch part 30 when viewed in a plan view. As a result, even in a case where the adherend has a protruding part on the adhesive surface, the adhesive film 3 can be stuck to the periphery of the protruding part without attaching the adhesive to the protruding part, by positioning the adhesive sheet such that the notch part 30 is located around the protruding part when viewed in a plan view. The shape of the notch part 30 is not limited to a semi-circular shape, and may be another regular shape such as a quadrangular shape or a triangular shape or may be an irregular shape. In the same manner as in the case where the release film 2 has the through-hole 4, even in a case where the entire circumference of the notch part 30 is not surrounded by the adhesive film 3, when 5% or more of the entire circumference of the notch part 30 is surrounded by the adhesive film 3, it is assumed that the adhesive film 3 is formed around the notch part 30. Furthermore, even in a case where the edges of the notch part 30 do not match the edges of the adhesive film 3, when the distance (shortest distance when viewed in a plan view) between the notch part 30 and the adhesive film 3 is 5 mm or less, it is assumed that the adhesive film 3 is formed around the notch part 30.

In addition, in the adhesive film 3, a hole (through-hole) may be formed at a site different from the site above the through-hole 4 of the release film 2. In this case, the shape, size, and number of the holes are not particularly limited.

In the above-described embodiment, the outer shape (planar shape) of the adhesive film is a rectangular shape; however, the outer shape of the adhesive film may be a polygonal shape, a circular shape, an elliptical shape, or the like or may be an irregular shape. Furthermore, the shapes of a plurality of the adhesive film may be identical with or different from each other.

In the above-described embodiment, the adhesive film 3 is composed of one layer; however, the adhesive film 3 may be composed of multiple layers. The adhesive film 3 may include, for example, a conductive particle layer containing conductive particles and a conductive particle-free layer that does not contain conductive particles. In this case, the adhesive film 3 may be formed such that the conductive particle-containing layer is on the opposite side of the release film 2.

Production Method for Adhesive Sheet

A production method for an adhesive sheet according to an embodiment is a production method for an adhesive sheet for semiconductor device production including a release film and an adhesive film provided on the release film. The production method for an adhesive sheet includes: a preparation step of preparing a backing material-attached laminated body including a laminated body and a backing material, the laminated body including the release film and an adhesive film layer provided on the release film, and the backing material being stuck to the release film side of the laminated body; a laminated body cutting step of making an incision in the laminated body along any cut-out shape; and a backing material peeling step of peeling the backing material from the laminated body, in which in the backing material peeling step, a portion of the laminated body existing in a region surrounded by the incision is attached to the backing material and removed.

The incision in the laminated body cutting step may be formed at the central portion of the laminated body or may be formed so as to surround a portion of the peripheral edge of the laminated body. In a case where the incision is formed so as to surround a portion of the peripheral edge of the laminated body, a notch part is formed by cutting out and removing an area including a portion of the above-described peripheral edge in the backing material peeling step.

The production method for an adhesive sheet may include: an adhesive film layer cutting step of making an incision in the adhesive film layer along an outline forming an outer shape of the adhesive film; and a margin peeling step of peeling, from the release film, a portion other than the portion removed in the backing material peeling step, in the margin portion constituting the portion other than the adhesive film in the adhesive film layer.

According to the above method, the above-described adhesive sheet (for example, adhesive sheets 1A, 1B, 1C, and 1D) is obtained. Hereinafter, the production method for an adhesive sheet according to the embodiment will be described by taking the production method for the adhesive sheet 1A as an example.

FIG. 5 is a schematic cross-sectional view for describing the production method for the adhesive sheet 1A, and FIG. 6 is a perspective view for describing the production method for the adhesive sheet 1A. The production method for the adhesive sheet 1A includes: a preparation step of preparing a backing material-attached laminated body 8 (see part (a) of FIG. 5 and part (a) of FIG. 6); a laminated body cutting step of making an incision (first incision) c1 in the laminated body 6 along any cut-out shape (see part (b) of FIG. 5 and part (b) of FIG. 6); an adhesive film layer cutting step of making an incision (second incision) c2 in the adhesive film layer 5 along an outline forming an outer shape of the adhesive film 3 (see part (b) of FIG. 5 and part (b) of FIG. 6); a backing material peeling step of peeling the backing material 7 from the laminated body 6 (see part (c) of FIG. 5 and part (c) of FIG. 6); and a margin peeling step of peeling, from the release film 2, a portion (peeled portion) 5B other than the portion removed in the backing material peeling step (adhesive film piece 5A), in the margin portion constituting the portion other than the adhesive film 3 in the adhesive film layer 5 (see part (d) of FIG. 5 and part (d) of FIG. 6). Each of the above-described steps will be described below.

(Preparation Step)

In the preparation step, a backing material-attached laminated body 8 is prepared. As shown in part (a) of FIG. 5 and part (a) of FIG. 6, the backing material-attached laminated body 8 includes a laminated body 6 and a backing material 7. The laminated body 6 includes a release film 2 and an adhesive film layer 5 provided on the release film 2. The adhesive film layer 5 is formed over, for example, the entirety of a principal surface 2a of the release film 2. The backing material 7 is stuck to the other principal surface 2b so as to cover the entirety of the principal surface 2b of the release film 2.

In the backing material 7, the principal surface on the side that is stuck to the release film 2 constitutes a surface that has tacky adhesiveness. Although not shown in the drawing, the backing material 7 is, for example, a tacky adhesive film including a resin film and a tacky adhesive layer formed on the resin film. The resin film is formed of, for example, polyethylene terephthalate (PET), polyethylene, polypropylene, or the like. The tacky adhesive layer is formed by using, for example, an acrylic resin, various synthetic rubbers, natural rubber, or a polyimide resin. The thickness of the backing material may be, for example, 20 to 100 mm.

The adhesive strength of the interface between the backing material 7 and the release film 2 in the backing material-attached laminated body 8 may be weaker than the adhesive strength of the interface between the adhesive film layer 5 and the release film 2, from the viewpoint of preventing the occurrence of peeling at the interface between the adhesive film layer 5 and the release film 2 in the backing material peeling step. For the adhesive strength of the interface between the backing material 7 and the release film 2 and the adhesive strength of the interface between the adhesive film layer 5 and the release film 2, a value measured by using an adhesive power tester (4000 Puls manufactured by Nordson Corporation) can be used. The adhesive strength of the interface between the backing material 7 and the release film 2 and the adhesive strength of the interface between the adhesive film layer 5 and the release film 2 can be adjusted by the type of the tacky adhesive layer of the backing material 7, the surface treatment for the principal surface 2a and the principal surface 2b of the release film 2, and the like.

The preparation step may be a step of producing the backing material-attached laminated body 8. For example, the preparation step may include: a step of forming the adhesive film layer 5 on one principal surface 2a of the release film 2; and a step of sticking the backing material 7 on the other principal surface 2b of the release film 2.

(Laminated Body Cutting Step)

In the laminated body cutting step, for example, the laminated body 6 is pressed against a roll cutter in which a cutting blade is formed on the outer peripheral surface. At this time, an incision c is made in the laminated body 6 from the adhesive film layer 5 side until the incision reaches to the backing material 7. As a result, a portion (removed portion) 6A existing in the region surrounded by the incision c1 is separated from the laminated body 6. The removed portion 6A is composed of a release film piece 2A and an adhesive film piece 5A. The incision c1 may be formed halfway through the backing material, so long as the backing material 7 is not cut. The cut-out shape (shape of the removed portion 6A) is a shape corresponding to the shape of the protruding part formed on the adhesive surface of the adherend, and is the same shape as the shape of the opening 4a of the through-hole 4 when viewed in a plan view.

(Adhesive Film Layer Cutting Step)

In the adhesive film layer cutting step, an incision c2 is made in the adhesive film layer 5 from the adhesive film layer 5 side until the incision reaches to the release film 2, in the same manner as in the laminated body cutting step. The incision c2 may be formed halfway through the release film so long as the release film