Sheet expansion method, method for manufacturing semiconductor device, and adhesive sheet

Abstract

The present invention provides a sheet expansion method, which comprises: a laminating step of laminating a plurality of adherends to a first adhesive layer (12) or a second adhesive layer (13) of an adhesive sheet (10); a sheet expansion step of stretching the adhesive sheet (10) to expand the intervals between the plurality of adherends; and an energy ray irradiation step of irradiating the first adhesive layer (12) and the second adhesive layer (13) with energy rays to cure the first adhesive layer (12) and the second adhesive layer (13), wherein the adhesive sheet (10) comprises a first adhesive layer (12) containing a first energy ray-curable resin, a second adhesive layer (13) containing a second energy ray-curable resin, and a substrate (11).

Description

Technical Field

[0001] The present invention relates to a wafer expansion method, a method for manufacturing a semiconductor device, and an adhesive sheet. Background Art

[0002] In recent years, the miniaturization, lightness and high functionality of electronic devices have been continuously developed. The semiconductor devices carried by electronic devices are also required to be miniaturized, thinned and high-density. Semiconductor chips are sometimes installed in packages close to their size. Such packages are sometimes also called chip scale packages (CSP). As one of the CSPs, wafer level packages (WLP) can be cited. In WLP, external electrodes are formed on the wafer before singulation by cutting, and the wafer is finally cut for singulation. As WLP, fan-in (Fan-In) type and fan-out (Fan-Out) type can be cited. In the fan-out type WLP (hereinafter, sometimes referred to as "FO-WLP"), the semiconductor chip is covered with a sealing material to form an area larger than the chip size to form a semiconductor chip sealed body, and a rewiring layer and external electrodes are formed not only on the circuit surface of the semiconductor chip, but also on the surface area of ​​the sealing material.

[0003] For example, Patent Document 1 describes a method for manufacturing a semiconductor package, which includes: for a plurality of semiconductor chips formed by singulation of a semiconductor wafer, retaining their circuit forming surfaces, surrounding them with a mold member to form an expanded wafer, and extending the rewiring pattern to an area outside the semiconductor chip to form a semiconductor package. In the manufacturing method described in Patent Document 1, before the plurality of semiconductor chips formed by singulation are surrounded by the mold member, they are alternately attached to the expansion sheet, and the expansion sheet is extended to increase the distance between the plurality of semiconductor chips.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2010 / 058646 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In the manufacturing method of the FO-WLP described above, there is the following problem: in order to form the above-mentioned rewiring pattern in the area outside the semiconductor chip, it is desired to stretch the expansion sheet (adhesive sheet) to sufficiently separate the semiconductor chips from each other and maintain the expanded state of the stretched adhesive sheet. Such a problem is not limited to semiconductor chips, but also applies to other adherends.

[0009] The present invention aims to provide an expanding method capable of maintaining the shape of an adhesive sheet after expansion in an expanding process, and an adhesive sheet used in the expanding method. Another object of the present invention is to provide a method for manufacturing a semiconductor device including the expanding method.

[0010] Solution to the problem

[0011] According to one embodiment of the present invention, a film expansion method may be provided, the method comprising:

[0012] Laminating step: laminating a plurality of adherends to a first adhesive layer or a second adhesive layer of an adhesive sheet, wherein the adhesive sheet comprises a first adhesive layer containing a first energy ray-curable resin, a second adhesive layer containing a second energy ray-curable resin, and a substrate between the first adhesive layer and the second adhesive layer;

[0013] A sheet expansion step: expanding the adhesive sheet to expand the intervals between the plurality of adherends; and

[0014] Energy ray irradiation step: irradiating the first adhesive layer and the second adhesive layer with energy rays to cure the first adhesive layer and the second adhesive layer.

[0015] In the sheet expanding method according to one embodiment of the present invention, it is preferable that the first energy ray-curable resin and the second energy ray-curable resin are the same.

[0016] In the sheet expanding method according to one embodiment of the present invention, it is preferred that the composition of the first adhesive layer is the same as that of the second adhesive layer.

[0017] In the sheet expanding method according to one embodiment of the present invention, it is preferable that the thickness of the first adhesive layer is the same as the thickness of the second adhesive layer.

[0018] In the sheet expansion method of one embodiment of the present invention, it is preferred that in the bonding process, the multiple adherends are bonded to the first adhesive layer, and in the energy ray irradiation process, energy rays are irradiated from the second adhesive layer side to cure the first adhesive layer and the second adhesive layer.

[0019] In the wafer expanding method according to one embodiment of the present invention, the adherend is preferably a semiconductor chip.

[0020] According to one embodiment of the present invention, a method for manufacturing a semiconductor device can be provided, which includes the above-mentioned expansion method of one embodiment of the present invention, wherein the manufacturing method includes: a process of cutting a workpiece bonded to a cutting adhesive sheet to obtain a plurality of single-piece adherends, in the above-mentioned bonding process, bonding the first adhesive layer or the second adhesive layer of the adhesive sheet to the side of the above-mentioned plurality of adherends opposite to the side in contact with the above-mentioned cutting adhesive sheet, and after the above-mentioned bonding process, performing a process of separating the above-mentioned cutting adhesive sheet from the above-mentioned plurality of adherends.

[0021] In the method for manufacturing a semiconductor device according to an embodiment of the present invention, it is preferable that the sheet expanding step is performed after the dicing adhesive sheet is separated from the plurality of adherends.

[0022] In a method for manufacturing a semiconductor device according to one embodiment of the present invention, the dicing adhesive sheet preferably contains expandable particles, and in the step of separating the dicing adhesive sheet from the plurality of adherends, the expandable particles are expanded to separate the plurality of adherends adhered to the adhesive sheet from the dicing adhesive sheet.

[0023] In a method for manufacturing a semiconductor device according to one embodiment of the present invention, the method preferably includes: a second transfer step, after the sheet expansion step, transferring the plurality of adherends to a second adhesive sheet having a second substrate and a third adhesive layer; and a third transfer step, transferring the plurality of adherends bonded to the second adhesive sheet to a third adhesive sheet having a third substrate and a fourth adhesive layer, wherein the third adhesive sheet contains expandable microparticles, in the second transfer step, bonding the third adhesive layer of the second adhesive sheet to a surface of the plurality of adherends opposite to a surface in contact with the first adhesive layer or the second adhesive layer, and separating the adhesive sheet from the plurality of adherends, and in the third transfer step, bonding the fourth adhesive layer of the third adhesive sheet to a surface of the plurality of adherends opposite to a surface in contact with the third adhesive layer, and separating the second adhesive sheet from the plurality of adherends.

[0024] According to one embodiment of the present invention, there can be provided an adhesive sheet comprising a first adhesive layer containing a first energy ray-curable resin, a second adhesive layer containing a second energy ray-curable resin, and a substrate between the first adhesive layer and the second adhesive layer. The adhesive sheet is used in a sheet expansion method, and the sheet expansion method comprises the following steps: a bonding step of bonding a plurality of adherends to the first adhesive layer or the second adhesive layer of the adhesive sheet; a sheet expansion step of stretching the adhesive sheet to expand the intervals between the plurality of adherends; and an energy ray irradiation step of irradiating the first adhesive layer and the second adhesive layer with energy rays to cure the first adhesive layer and the second adhesive layer.

[0025] In the pressure-sensitive adhesive sheet according to one embodiment of the present invention, it is preferred that the first energy-ray-curable resin and the second energy-ray-curable resin are the same.

[0026] In the pressure-sensitive adhesive sheet according to one embodiment of the present invention, it is preferred that the composition of the first pressure-sensitive adhesive layer is the same as the composition of the second pressure-sensitive adhesive layer.

[0027] In the pressure-sensitive adhesive sheet according to one embodiment of the present invention, it is preferred that the thickness of the first pressure-sensitive adhesive layer is the same as the thickness of the second pressure-sensitive adhesive layer.

[0028] According to the present invention, a sheet expansion method capable of maintaining the shape of an adhesive sheet expanded in a sheet expansion step and an adhesive sheet used in the sheet expansion method can be provided. According to another embodiment of the present invention, a semiconductor device manufacturing method including the sheet expansion method can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic cross-sectional view of a pressure-sensitive adhesive sheet according to one embodiment of the present invention.

[0030] Figure 2 This is a top view for explaining a biaxially stretched sheet expansion device.

[0031] Figure 3A This is a cross-sectional view for explaining a first embodiment of a method for using a pressure-sensitive adhesive sheet according to one embodiment of the present invention.

[0032] Figure 3B This is a cross-sectional view for explaining a first embodiment of a method for using a pressure-sensitive adhesive sheet according to one embodiment of the present invention.

[0033] Figure 3C This is a cross-sectional view for explaining a first embodiment of a method for using a pressure-sensitive adhesive sheet according to one embodiment of the present invention.

[0034] Figure 4AThis is a cross-sectional view for explaining a first embodiment of a method for using a pressure-sensitive adhesive sheet according to one embodiment of the present invention.

[0035] Figure 4B This is a cross-sectional view for explaining a first embodiment of a method for using a pressure-sensitive adhesive sheet according to one embodiment of the present invention.

[0036] Figure 5A This is a cross-sectional view for explaining a first embodiment of a method for using a pressure-sensitive adhesive sheet according to one embodiment of the present invention.

[0037] Figure 5B This is a cross-sectional view for explaining a first embodiment of a method for using a pressure-sensitive adhesive sheet according to one embodiment of the present invention.

[0038] Figure 5C This is a cross-sectional view for explaining a first embodiment of a method for using a pressure-sensitive adhesive sheet according to one embodiment of the present invention.

[0039] Figure 5D This is a cross-sectional view for explaining a first embodiment of a method for using a pressure-sensitive adhesive sheet according to one embodiment of the present invention.

[0040] Figure 6 This is a schematic cross-sectional view of a modified PSA sheet according to an embodiment of the present invention.

[0041] Explanation of symbols

[0042] 10···Adhesive sheet

[0043] 11···Base material

[0044] 12···First adhesive layer

[0045] 13···Second adhesive layer

[0046] 20···Second adhesive sheet

[0047] 21···Second substrate

[0048] 22···Third adhesive layer

[0049] 30···Third adhesive sheet

[0050] 31···Third base material

[0051] 32···Fourth adhesive layer

[0052] A···Adhesive Sheet for Dicing

[0053] CP···Semiconductor chip (adherent) DETAILED DESCRIPTION

[0054] Hereinafter, one embodiment of the present invention will be described.

[0055] The pressure-sensitive adhesive sheet of the present embodiment includes a substrate, a first pressure-sensitive adhesive layer containing a first energy-ray-curable resin, and a second pressure-sensitive adhesive layer containing a second energy-ray-curable resin.

[0056] [Adhesive sheet]

[0057] Figure 1 A cross-sectional schematic diagram of an adhesive sheet 10 of an embodiment of the present embodiment is shown. The adhesive sheet 10 has a substrate 11, a first adhesive layer 12, and a second adhesive layer 13. The shape of the adhesive sheet 10 can be, for example, any shape such as a strip (a strip form) and a label (a sheet form). In order to distinguish the adhesive sheet of the present embodiment from other adhesive sheets, it is sometimes referred to as a first adhesive sheet.

[0058] (Base material)

[0059] The substrate 11 has a first substrate surface 11A and a second substrate surface 11B opposite to the first substrate surface 11A. In the adhesive sheet 10 of the present embodiment, the first adhesive layer 12 is provided on the first substrate surface 11A, and the second adhesive layer 13 is provided on the second substrate surface 11B.

[0060] From the viewpoint of being easily stretched to a large extent, the material of the substrate 11 is preferably a thermoplastic elastomer or a rubber-based material, and more preferably a thermoplastic elastomer.

[0061] In addition, from the viewpoint of being easy to stretch greatly, a resin with a low glass transition temperature (Tg) is preferably used as the material of the substrate 11. The glass transition temperature (Tg) of such a resin is preferably 90°C or lower, more preferably 80°C or lower, and further preferably 70°C or lower.

[0062] Examples of the thermoplastic elastomer include urethane elastomers, olefin elastomers, vinyl chloride elastomers, polyester elastomers, styrene elastomers, acrylic elastomers, and amide elastomers. The thermoplastic elastomer may be used alone or in combination of two or more.

[0063] As the thermoplastic elastomer, a urethane elastomer is preferably used from the viewpoint of being easily stretched to a large extent.

[0064] Urethane elastomers are generally obtained by reacting long-chain polyols, chain extenders, and diisocyanates. Urethane elastomers include soft segments and hard segments, wherein the soft segments have structural units derived from long-chain polyols, and the hard segments have polyurethane structures obtained by reacting chain extenders and diisocyanates.

[0065] If classified according to the type of long-chain polyol, urethane elastomers can be divided into polyester polyurethane elastomers, polyether polyurethane elastomers, and polycarbonate polyurethane elastomers. One type of urethane elastomer can be used alone, or two or more types can be used in combination. In the present embodiment, from the viewpoint of being easy to stretch significantly, the urethane elastomer is preferably a polyether polyurethane elastomer.

[0066] Examples of long-chain polyols include polyester polyols such as lactone polyester polyols and adipic acid ester polyester polyols, polyether polyols such as polypropylene (ethylene) polyols and polytetramethylene ether glycol, polycarbonate polyols, etc. In this embodiment, the long-chain polyol is preferably an adipic acid ester polyester polyol from the viewpoint of being easy to stretch.

[0067] Examples of diisocyanates include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4′-diphenylmethane diisocyanate, and hexamethylene diisocyanate. In the present embodiment, the diisocyanate is preferably hexamethylene diisocyanate from the viewpoint of facilitating large-scale stretching.

[0068] Examples of the chain extender include low molecular weight polyols (eg, 1,4-butanediol and 1,6-hexanediol), aromatic diamines, etc. Among them, 1,6-hexanediol is preferably used because it is easy to stretch the chain to a large extent.

[0069] As the olefin elastomer, there can be mentioned an elastomer containing at least one resin selected from ethylene / α-olefin copolymers, propylene / α-olefin copolymers, butene / α-olefin copolymers, ethylene / propylene / α-olefin copolymers, ethylene / butene / α-olefin copolymers, propylene / butene / α-olefin copolymers, ethylene / propylene / butene / α-olefin copolymers, styrene / isoprene copolymers, and styrene / ethylene / butene copolymers. The olefin elastomer can be used alone or in combination of two or more.

[0070] The density of the olefin elastomer is not particularly limited. For example, the density of the olefin elastomer is preferably 0.860 g / cm 3 Above and less than 0.905g / cm 3 , more preferably 0.862 g / cm 3 Above and less than 0.900g / cm 3 , particularly preferably 0.864 g / cm 3 Above and less than 0.895g / cm 3 When the density of the olefin elastomer satisfies the above range, the substrate 11 has excellent properties such as conformability to uneven surfaces when a semiconductor wafer as an adherend is attached to the pressure-sensitive adhesive sheet.

[0071] In the olefin-based elastomer, the mass ratio of monomers containing olefin-based compounds in all monomers used to form the elastomer (also referred to as “olefin content” in this specification) is preferably 50 mass % or more and 100 mass % or less.

[0072] When the olefin content is too low, the properties of the elastomer containing the structural unit derived from the olefin are difficult to be expressed, and the substrate 11 is difficult to show flexibility and rubber elasticity.

[0073] From the viewpoint of stably obtaining flexibility and rubber elasticity, the olefin content is preferably 50% by mass or more, more preferably 60% by mass or more.

[0074] Examples of styrene-based elastomers include styrene-conjugated diene copolymers and styrene-olefin copolymers. Specific examples of styrene-conjugated diene copolymers include unhydrogenated styrene-conjugated diene copolymers such as styrene-butadiene copolymers, styrene-butadiene-styrene copolymers (SBS), styrene-butadiene-butylene-styrene copolymers, styrene-isoprene copolymers, styrene-isoprene-styrene copolymers (SIS), styrene-ethylene-isoprene-styrene copolymers, styrene-ethylene / propylene-styrene copolymers (SEPS, hydrogenated products of styrene-isoprene-styrene copolymers), and hydrogenated styrene-conjugated diene copolymers such as styrene-ethylene-butylene-styrene copolymers (SEBS, hydrogenated products of styrene-butadiene copolymers). In addition, in industry, styrene-based elastomers include trade names such as Tufprene (manufactured by Asahi Kasei Corporation), Kraton (manufactured by Kraton Polymers Japan), Sumitomo TPE-SB (manufactured by Sumitomo Chemical Co., Ltd.), EPOFRIEND (manufactured by Daicel Corporation), Rubberron (manufactured by Mitsubishi Chemical Corporation), Septon (manufactured by Kuraray Co., Ltd.), and Tuftec (manufactured by Asahi Kasei Corporation). The styrene-based elastomer may be a hydrogenated product or an unhydrogenated product. The styrene-based elastomer may be used alone or in combination of two or more.

[0075] Examples of rubber materials include natural rubber, synthetic isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), nitrile rubber (NBR), butyl rubber (IIR), halogenated butyl rubber, acrylic rubber, urethane rubber, and polysulfide rubber. The rubber material may be used alone or in combination of two or more.

[0076] The substrate 11 may also be a laminated film formed by laminating a plurality of films formed by the above-mentioned materials (e.g., thermoplastic elastomers or rubber-like materials). In addition, the substrate 11 may also be a laminated film formed by laminating a film formed by the above-mentioned materials (e.g., thermoplastic elastomers or rubber-like materials) and another film.

[0077] The substrate 11 may contain additives in a film made mainly of the above-mentioned resin material.

[0078] Examples of additives include pigments, dyes, flame retardants, plasticizers, antistatic agents, lubricants, and fillers. Examples of pigments include titanium dioxide and carbon black. In addition, examples of fillers include organic materials such as melamine resins, inorganic materials such as fumed silica, and metal materials such as nickel particles. The content of such additives is not particularly limited, but preferably falls within a range that enables the substrate 11 to perform the desired function.

[0079] For substrate 11, in order to improve its adhesion with the adhesive layer (first adhesive layer 12 and second adhesive layer 13) stacked on the first substrate surface 11A and the second substrate surface 11B, surface treatment or primer treatment can be applied to one side or both sides as needed. As surface treatment, oxidation method and concavoconvex method can be cited. As primer treatment, a method for forming a primer layer on the surface of substrate 11 can be cited. As oxidation method, for example: corona discharge treatment, plasma discharge treatment, chromium oxidation treatment (wet), flame treatment, hot air treatment, ozone treatment, and ultraviolet irradiation treatment can be cited. As concavoconvex method, for example, sandblasting method and spray treatment method can be cited.

[0080] Since the first adhesive layer 12 and the second adhesive layer 13 contain an energy ray-curable adhesive, it is preferred that the substrate 11 has energy ray transparency. When the energy ray-curable adhesive is an ultraviolet-curable adhesive, the substrate 11 preferably has ultraviolet transparency. When the energy ray-curable adhesive is an electron beam-curable adhesive, the substrate 11 preferably has electron beam transparency.

[0081] The thickness of the substrate 11 is not limited as long as the adhesive sheet 10 can properly function in the desired process. The thickness of the substrate 11 is preferably 20 μm or more, more preferably 40 μm or more. In addition, the thickness of the substrate 11 is preferably 250 μm or less, more preferably 200 μm or less.

[0082] In addition, when the thickness of multiple locations is measured at 2 cm intervals in the in-plane direction of the first substrate surface 11A or the second substrate surface 11B of the substrate 11, the standard deviation of the thickness of the substrate 11 is preferably 2 μm or less, more preferably 1.5 μm or less, and further preferably 1 μm or less. By making the standard deviation 2 μm or less, the adhesive sheet 10 has a high-precision thickness and can be stretched uniformly.

[0083] At 23°C, the tensile elastic modulus of the substrate 11 in the MD and CD directions is 10 MPa to 350 MPa, respectively. At 23°C, the 100% stress of the substrate 11 in the MD and CD directions is 3 MPa to 20 MPa, respectively.

[0084] By setting the tensile elastic modulus and 100% stress within the above ranges, the pressure-sensitive adhesive sheet 10 can be stretched to a large extent.

[0085] The 100% stress of the substrate 11 is a value obtained as follows. A test piece of 150 mm (length direction) × 15 mm (width direction) is cut from the substrate 11. The two ends of the cut test piece in the length direction are clamped with a clamp so that the length between the clamps is 100 mm. After the test piece is clamped with the clamp, it is stretched in the length direction at a speed of 200 mm / min, and the measured value of the tensile force is read when the length between the clamps reaches 200 mm. The 100% stress of the substrate 11 is the value obtained by dividing the measured value of the tensile force read by the cross-sectional area of ​​the substrate 11. The cross-sectional area of ​​the substrate 11 is calculated according to the width length 15 mm × the thickness of the substrate 11 (test piece). The cutting is performed in such a way that the running direction (MD direction) or the direction perpendicular to the MD direction (CD direction) when the substrate 11 is manufactured is consistent with the length direction of the test piece. It should be noted that in this tensile test, the thickness of the test piece is not particularly limited and can be the same as the thickness of the substrate as the test object.

[0086] At 23° C., the elongations at break of the substrate 11 in the MD direction and the CD direction are preferably 100% or more, respectively.

[0087] When the elongations at break of the substrate 11 in the MD direction and the CD direction are each 100% or more, the pressure-sensitive adhesive sheet 10 can be stretched to a large extent without breaking.

[0088] The tensile modulus of elasticity (MPa) of the substrate and the elongation at break (%) of the substrate can be measured as described below. The substrate is cut into 15mm×140mm to obtain a test piece. For the test piece, the elongation at break and the tensile modulus at 23°C are measured according to JIS K7161:2014 and JIS K7127:1999. Specifically, for the above-mentioned test piece, a tensile testing machine (manufactured by Shimadzu Corporation, product name "Autograph AG-IS 500N") is used, the distance between the chucks is set to 100mm, and then a tensile test is performed at a speed of 200mm / min to measure the elongation at break (%) and the tensile modulus (MPa). It should be noted that the measurement is carried out in two directions: the direction of travel (MD) when the substrate is manufactured and the direction (CD) at right angles thereto.

[0089] (Adhesive layer)

[0090] In the pressure-sensitive adhesive sheet 10 of the present embodiment, the first pressure-sensitive adhesive layer 12 and the second pressure-sensitive adhesive layer 13 contain an energy-ray-curable pressure-sensitive adhesive.

[0091] It is preferable that the first energy-ray-curable resin contained in the first adhesive layer 12 and the second energy-ray-curable resin contained in the second adhesive layer 13 are the same resin.

[0092] More preferably, the composition of the first adhesive layer 12 is the same as the composition of the second adhesive layer 13 .

[0093] The thickness of the first adhesive layer 12 and the second adhesive layer 13 is not particularly limited.

[0094] The thickness of the first adhesive layer 12 and the second adhesive layer 13 is preferably 10 μm or more, more preferably 20 μm or more, for example. The thickness of the first adhesive layer 12 and the second adhesive layer 13 is preferably 150 μm or less, more preferably 100 μm or less.

[0095] It is preferred that the thickness of the first adhesive layer 12 is the same as the thickness of the second adhesive layer 13 .

[0096] By making the first energy ray-curable resin and the second energy ray-curable resin the same resin and making the thickness of the first adhesive layer 12 the same as the thickness of the second adhesive layer 13, the difference in shrinkage when the first adhesive layer 12 and the second adhesive layer 13 are cured can be eliminated or reduced, thereby suppressing the curling of the adhesive sheet 10.

[0097] By making the composition of the first adhesive layer 12 the same as the composition of the second adhesive layer 13 and making the thickness of the first adhesive layer 12 the same as the thickness of the second adhesive layer 13, the difference in shrinkage when the first adhesive layer 12 and the second adhesive layer 13 are cured can be eliminated or reduced, thereby further suppressing the curling of the adhesive sheet 10.

[0098] It should be noted that the first energy-ray-curable resin contained in the first adhesive layer 12 and the second energy-ray-curable resin contained in the second adhesive layer 13 may be different resins. In this case, it is preferred that the composition of the first adhesive layer 12 and the second adhesive layer 13, as well as the thickness of the adhesive layer, can eliminate or reduce the difference between the amount of shrinkage when the first adhesive layer 12 is cured and the amount of shrinkage when the second adhesive layer 13 is cured. In order to eliminate or reduce the difference in shrinkage, for example, it is possible to appropriately select from the materials that can be used for the adhesive layer described later, and adjust the composition of the first adhesive layer 12 and the second adhesive layer 13, as well as the thickness of the adhesive layer.

[0099] The first energy ray curable resin and the second energy ray curable resin are preferably ultraviolet curable resins. In this case, even if the energy rays irradiated to each adhesive layer are not changed, the first adhesive layer 12 and the second adhesive layer 13 can be cured by ultraviolet rays, thereby simplifying the manufacturing process.

[0100] Energy ray curable resin (a1)

[0101] It is preferred that the first adhesive layer 12 and the second adhesive layer 13 each independently contain an energy-ray curable resin (a1). The energy-ray curable resin (a1) has an energy-ray curable double bond in the molecule.

[0102] The adhesive layer containing the energy-ray curable resin is cured by energy-ray irradiation. Therefore, by curing the first adhesive layer 12 and the second adhesive layer 13 provided on both sides of the substrate 11 after the adhesive sheet 10 is stretched, the expanded state of the adhesive sheet 10 can be easily maintained.

[0103] In addition, the adhesive layer containing the energy-ray curable resin is cured by energy-ray irradiation, and the adhesive force is reduced. When the adherend and the adhesive sheet are to be separated, they can be easily separated by irradiating the adhesive layer with energy rays.

[0104] The energy beam curable resin (a1) is preferably a (meth)acrylic resin.

[0105] The energy ray curable resin (a1) is preferably an ultraviolet curable resin, and more preferably an ultraviolet curable (meth)acrylic resin.

[0106] The energy-ray-curable resin (a1) is a resin that is polymerized and cured when irradiated with energy rays. Examples of the energy rays include ultraviolet rays and electron beams.

[0107] As examples of energy-ray curable resins (a1), low molecular weight compounds (monofunctional monomers, polyfunctional monomers, monofunctional oligomers, and polyfunctional oligomers) having energy-ray polymerizable groups can be cited. Energy-ray curable resins (a1) can specifically use acrylates such as trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, dipentaerythritol monohydroxy pentaacrylate, dipentaerythritol hexaacrylate, 1,4-butanediol diacrylate, and 1,6-hexanediol diacrylate, dicyclopentadiene dimethoxy diacrylate, and acrylates containing cyclic aliphatic skeletons such as isobornyl acrylate, and acrylate compounds such as polyethylene glycol diacrylate, oligoester acrylate, urethane acrylate oligomer, epoxy-modified acrylate, polyether acrylate, and itaconic acid oligomer. Energy-ray curable resins (a1) can be used alone or in combination of two or more.

[0108] The molecular weight of the energy beam curable resin (a1) is usually 100 or more and 30,000 or less, and preferably about 300 or more and 10,000 or less.

[0109] ·(Meth)acrylic acid copolymer (b1)

[0110] It is preferred that the first adhesive layer 12 and the second adhesive layer 13 each independently further contain a (meth)acrylic copolymer (b1). The (meth)acrylic copolymer is different from the energy-beam-curable resin (a1) described above.

[0111] The (meth)acrylic copolymer (b1) preferably has an energy-ray-curable carbon-carbon double bond. That is, in this embodiment, the first adhesive layer 12 and the second adhesive layer 13 each independently preferably contain an energy-ray-curable resin (a1) and an energy-ray-curable (meth)acrylic copolymer (b1).

[0112] The first adhesive layer 12 and the second adhesive layer 13 each independently preferably contain the energy ray curable resin (a1) in a ratio of 10 parts by mass or more, more preferably 20 parts by mass or more, and further preferably 25 parts by mass or more, relative to 100 parts by mass of the (meth)acrylic copolymer (b1).

[0113] The first adhesive layer 12 and the second adhesive layer 13 each independently preferably contain the energy ray curable resin (a1) in a ratio of 80 parts by mass or less, more preferably 70 parts by mass or less, and even more preferably 60 parts by mass or less, based on 100 parts by mass of the (meth)acrylic copolymer (b1).

[0114] The weight average molecular weight (Mw) of the (meth)acrylic copolymer (b1) is preferably 10,000 or more, more preferably 150,000 or more, and even more preferably 200,000 or more.

[0115] The weight average molecular weight (Mw) of the (meth)acrylic copolymer (b1) is preferably 1.5 million or less, and more preferably 1 million or less.

[0116] In addition, the weight average molecular weight (Mw) in this specification is a value converted into standard polystyrene measured by gel permeation chromatography (GPC method).

[0117] The (meth)acrylic copolymer (b1) is preferably a (meth)acrylate polymer (b2) having an energy-ray-curable functional group (energy-ray-curable group) introduced into a side chain (hereinafter sometimes referred to as “energy-ray-curable polymer (b2)”).

[0118] The energy-ray-curable polymer (b2) is preferably a copolymer obtained by reacting an acrylic copolymer (b21) having a monomer unit containing a functional group with an unsaturated group-containing compound (b22) having a functional group bonded to the functional group. It should be noted that in this specification, (meth)acrylate refers to both acrylate and methacrylate. The same applies to other similar terms.

[0119] The acrylic copolymer (b21) preferably includes a structural unit derived from a functional group-containing monomer and a structural unit derived from a (meth)acrylic acid ester monomer or a (meth)acrylic acid ester monomer derivative.

[0120] The functional group-containing monomer as a structural unit of the acrylic copolymer (b21) is preferably a monomer having a polymerizable double bond and a functional group in the molecule. The functional group is preferably at least one functional group selected from hydroxyl, carboxyl, amino, substituted amino, and epoxy groups.

[0121] Examples of the hydroxyl-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. The hydroxyl-containing monomer may be used alone or in combination of two or more.

[0122] Examples of the carboxyl group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. The carboxyl group-containing monomer may be used alone or in combination of two or more.

[0123] Examples of the amino group-containing monomer or substituted amino group-containing monomer include aminoethyl (meth)acrylate and n-butylaminoethyl (meth)acrylate. The amino group-containing monomer or substituted amino group-containing monomer may be used alone or in combination of two or more.

[0124] As the (meth)acrylate monomer constituting the acrylic copolymer (b21), in addition to (meth)acrylate alkyl esters having an alkyl group carbon number of 1 to 20, for example, monomers having an alicyclic structure in the molecule (alicyclic structure-containing monomers) can be preferably used.

[0125] As the alkyl (meth)acrylate, an alkyl (meth)acrylate having an alkyl carbon number of 1 to 18 is preferred. More preferred alkyl (meth)acrylates include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. The alkyl (meth)acrylate may be used alone or in combination of two or more.

[0126] As the alicyclic structure-containing monomer, for example, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, adamantyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate can be preferably used. The alicyclic structure-containing monomer can be used alone or in combination of two or more.

[0127] The acrylic copolymer (b21) preferably contains the structural unit derived from the functional group-containing monomer in a ratio of 1% by mass or more, more preferably 5% by mass or more, and further preferably 10% by mass or more.

[0128] The acrylic copolymer (b21) preferably contains the structural unit derived from the functional group-containing monomer in a ratio of 35% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less.

[0129] The acrylic copolymer (b21) preferably contains 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, of a structural unit derived from a (meth)acrylate monomer or a derivative thereof.

[0130] The acrylic copolymer (b21) preferably contains a structural unit derived from a (meth)acrylate monomer or a derivative thereof in a ratio of 99% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less.

[0131] The acrylic copolymer (b21) can be obtained by copolymerizing the above-mentioned functional group-containing monomer and a (meth)acrylic acid ester monomer or a derivative thereof by a common method.

[0132] The acrylic copolymer (b21) may contain at least one structural unit selected from dimethylacrylamide, vinyl formate, vinyl acetate, styrene and the like in addition to the above-mentioned monomers.

[0133] The energy ray-curable polymer (b2) can be obtained by reacting the acrylic copolymer (b21) having the above-mentioned functional group-containing monomer unit with the unsaturated group-containing compound (b22) having a functional group bonded to the functional group thereof.

[0134] The functional group of the unsaturated group-containing compound (b22) can be appropriately selected according to the type of functional group of the functional group-containing monomer unit of the acrylic copolymer (b21). For example, when the functional group of the acrylic copolymer (b21) is hydroxyl, amino or substituted amino, the functional group of the unsaturated group-containing compound (b22) is preferably an isocyanate group or an epoxy group, and when the functional group of the acrylic copolymer (b21) is an epoxy group, the functional group of the unsaturated group-containing compound (b22) is preferably an amino, carboxyl or aziridine group.

[0135] The unsaturated group-containing compound (b22) contains at least one energy-ray-polymerizable carbon-carbon double bond in one molecule, preferably one or more and six or less, and more preferably one or more and four or less.

[0136] Examples of the unsaturated group-containing compound (b22) include: 2-methacryloyloxyethyl isocyanate (2-isocyanatoethyl methacrylate), m-isopropenyl-α,α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1,1-(bisacryloyloxymethyl)ethyl isocyanate; acryloyl monoisocyanate compounds obtained by the reaction of a diisocyanate compound or a polyisocyanate compound with hydroxyethyl (meth)acrylate; acryloyl monoisocyanate compounds obtained by the reaction of a diisocyanate compound or a polyisocyanate compound, a polyol compound, and hydroxyethyl (meth)acrylate; glycidyl (meth)acrylate; (meth)acrylic acid, 2-(1-aziridinyl)ethyl (meth)acrylate, 2-vinyl-2- Oxazoline, 2-isopropenyl-2- Oxazoline, etc.

[0137] The unsaturated group-containing compound (b22) is preferably used in a ratio (addition rate) of 50 mol % or more, more preferably 60 mol % or more, and further preferably 70 mol % or more, relative to the molar number of the functional group-containing monomer in the acrylic copolymer (b21).

[0138] In addition, the unsaturated group-containing compound (b22) is preferably used in a ratio of 95 mol% or less, more preferably 93 mol% or less, and further preferably 90 mol% or less, relative to the molar number of the functional group-containing monomer of the acrylic copolymer (b21).

[0139] In the reaction of the acrylic copolymer (b21) and the unsaturated group-containing compound (b22), the temperature, pressure, solvent, time, presence or absence of a catalyst, and the type of catalyst can be appropriately selected according to the combination of the functional groups of the acrylic copolymer (b21) and the functional groups of the unsaturated group-containing compound (b22). Thus, the functional groups of the acrylic copolymer (b21) react with the functional groups of the unsaturated group-containing compound (b22), and unsaturated groups are introduced into the side chains of the acrylic copolymer (b21), thereby obtaining an energy-ray-curable polymer (b2).

[0140] The weight average molecular weight (Mw) of the energy beam curable polymer (b2) is preferably 10,000 or more, more preferably 150,000 or more, and even more preferably 200,000 or more.

[0141] The weight average molecular weight (Mw) of the energy beam curable polymer (b2) is preferably 1.5 million or less, and more preferably 1 million or less.

[0142] Photopolymerization initiator (C)

[0143] The first adhesive layer 12 and the second adhesive layer 13 each independently preferably contain a photopolymerization initiator (C). When the first adhesive layer 12 and the second adhesive layer 13 contain a photopolymerization initiator (C), the polymerization curing time and the light irradiation amount can be reduced.

[0144] Specific examples of the photopolymerization initiator (C) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoylbenzoic acid, benzoylbenzoic acid methyl ester, benzoin dimethyl ether, 2,4-diethylthiazolone, 1-hydroxycyclohexylphenyl ketone, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzil, bibenzyl, diacetyl, β-chloroanthraquinone, (2,4,6-trimethylbenzyldiphenyl)phosphine oxide, 2-benzothiazolyl N,N-diethyldithiocarbamate, oligomeric {2-hydroxy-2-methyl-1-[4-(1-propenyl)phenyl]propanone}, and 2,2-dimethoxy-1,2-diphenylethane-1-one. These photopolymerization initiators (C) may be used alone or in combination of two or more.

[0145] When the energy-ray curable resin (a1) and the (meth) acrylic copolymer (b1) are blended in the adhesive layer, the photopolymerization initiator (C) is preferably used in an amount of 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, based on 100 parts by mass of the total amount of the energy-ray curable resin (a1) and the (meth) acrylic copolymer (b1).

[0146] In addition, when an energy-ray curable resin (a1) and a (meth) acrylic copolymer (b1) are formulated in the adhesive layer, the photopolymerization initiator (C) is preferably used in an amount of 10 parts by mass or less, and more preferably used in an amount of 6 parts by mass or less, relative to 100 parts by mass of the total amount of the energy-ray curable resin (a1) and the (meth) acrylic copolymer (b1).

[0147] In addition to the above-mentioned components, other components may be appropriately blended into the first adhesive layer 12 and the second adhesive layer 13. Examples of other components include a crosslinking agent (E) and the like.

[0148] Cross-linking agent (E)

[0149] As the crosslinking agent (E), a polyfunctional compound reactive with the functional group of the (meth)acrylic copolymer (b1) or the like can be used. Examples of such polyfunctional compounds include isocyanate compounds, epoxy compounds, amine compounds, melamine compounds, aziridine compounds, hydrazine compounds, aldehyde compounds, Oxazoline compounds, metal alkoxide compounds, metal chelate compounds, metal salts, ammonium salts, and reactive phenolic resins, etc.

[0150] The amount of the crosslinking agent (E) to be added is preferably 0.01 parts by mass or more, more preferably 0.03 parts by mass or more, and even more preferably 0.04 parts by mass or more, based on 100 parts by mass of the (meth)acrylic copolymer (b1).

[0151] The amount of the crosslinking agent (E) is preferably 8 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3.5 parts by mass or less, based on 100 parts by mass of the (meth)acrylic copolymer (b1).

[0152] The recovery rate of the adhesive sheet of this embodiment is preferably 70% or more, more preferably 80% or more, and even more preferably 85% or more. The recovery rate of the adhesive sheet of this embodiment is preferably 100% or less. By setting the recovery rate in the above range, the adhesive sheet can be stretched significantly.

[0153] The above recovery rate is obtained in the following manner: for a test piece of 150 mm (length direction) × 15 mm (width direction) cut into the adhesive sheet 10, the two ends of the length direction are clamped with a clamp and the length between the clamps is 100 mm, then, it is stretched at a speed of 200 mm / min until the length between the clamps reaches 200 mm, and the length between the clamps is maintained for 1 minute in a state where the length between the clamps is expanded to 200 mm, and then, it is restored in the length direction at a speed of 200 mm / min until the length between the clamps is 100 mm, and the length between the clamps is maintained for 1 minute after the length between the clamps is restored to 100 mm, and then, it is stretched in the length direction at a speed of 60 mm / min, and the length between the clamps when the measured value of the tensile force shows 0.1 N / 15 mm is measured, and the length obtained by subtracting the initial length between the clamps of 100 mm from the length is set as L2 (mm), and the length obtained by subtracting the initial length between the clamps of 100 mm from the length between the clamps in the above expanded state is set as L1 (mm), and the following formula (Mathematical Formula 2) is used for calculation.

[0154] Recovery rate (%) = {1-(L2÷L1)}×100···(Formula 2)

[0155] (Peel-off Sheet)

[0156] For the adhesive sheet 10 of the present embodiment, before the adherend (e.g., semiconductor chip, etc.) is attached to the first adhesive layer 12 or the second adhesive layer 13, a release sheet may be laminated on the first adhesive layer 12 and the second adhesive layer 13 to protect the first adhesive layer 12 and the second adhesive layer 13. The structure of the release sheet is arbitrary. As an example of the release sheet, a plastic film subjected to a release treatment using a release agent or the like can be exemplified.

[0157] Specific examples of plastic films include polyester films and polyolefin films. Polyester films include films of polyethylene terephthalate, polybutylene terephthalate, or polyethylene naphthalate. Polyolefin films include films of polypropylene or polyethylene.

[0158] As the release agent, silicone-based, fluorine-based, and long-chain alkyl-based release agents can be used. Among these release agents, silicone-based release agents are preferred because they are inexpensive and can provide stable performance.

[0159] The thickness of the release sheet is not particularly limited, and is usually 20 μm or more and 250 μm or less.

[0160] (Method for producing adhesive sheet)

[0161] The pressure-sensitive adhesive sheet 10 of the present embodiment can be produced in the same manner as conventional pressure-sensitive adhesive sheets.

[0162] The method for producing the pressure-sensitive adhesive sheet 10 is not particularly limited as long as the first pressure-sensitive adhesive layer 12 can be laminated on the first substrate surface 11A of the substrate 11 and the second pressure-sensitive adhesive layer 13 can be laminated on the second substrate surface 11B.

[0163] As a first example of a method for manufacturing the adhesive sheet 10, the following method can be cited. First, a coating liquid (sometimes referred to as a first coating liquid) containing an adhesive composition constituting the first adhesive layer 12 and a solvent or dispersion medium added as needed, and a coating liquid (sometimes referred to as a second coating liquid) containing an adhesive composition constituting the second adhesive layer 13 and a solvent or dispersion medium added as needed are prepared. Next, the first coating liquid is applied to the surface of the first substrate surface 11A of the substrate 11 by a coating mechanism to form a coating film. As a coating mechanism, for example: a die coater, a curtain coater, a spray coater, a slit coater, and a scraper coater can be cited. Next, by drying the coating film, the first adhesive layer 12 can be formed. As long as the coating liquid can be applied, its properties are not particularly limited. The coating liquid contains both a component for forming an adhesive layer as a solute and a component for forming an adhesive layer as a dispersion medium. For the second adhesive layer 13, the second coating liquid can be applied to the surface of the second substrate surface 11B of the substrate 11, and it is formed in the same way as the first adhesive layer 12. As a modification of the first example, the second adhesive layer 13 may be formed first, and then the first adhesive layer 12 may be formed.

[0164] In addition, as a second example of a method for manufacturing an adhesive sheet, the following method can be cited. First, a first coating liquid is applied to the release surface of the above-mentioned release sheet to form a first coating film. Next, the first coating film is dried to form a laminate consisting of a first adhesive layer 12 and a release sheet. Next, a substrate 11 is attached to the surface of the adhesive layer of the laminate that is opposite to the release sheet side. Next, a second coating liquid is applied to the exposed surface of the substrate 11 to form a second coating film. The second coating film is dried to form a second adhesive layer 13. Thus, a laminate having a release sheet, a first adhesive layer 12, a substrate 11 and a second adhesive layer 13 is formed. A release sheet can be further stacked on the second adhesive layer 13 of the laminate. The release sheet in the laminate can be peeled off as a process material, or it can protect the adhesive layer until an adherend (e.g., a semiconductor chip and a semiconductor wafer, etc.) is attached to the adhesive layer. As a modification of the second example, there may be a method in which a laminate composed of a release sheet, the second adhesive layer 13 and the substrate 11 is first formed, and then the first adhesive layer 12 is formed on the laminate.

[0165] In addition, as a third example of a method for manufacturing an adhesive sheet, the following method can be cited. A first laminated body formed by stacking a release sheet (first release sheet), a first adhesive layer 12 and a substrate 11 is formed in the same manner as in the second example described above. On the other hand, a second coating liquid is applied to the release surface of another release sheet (second release sheet) to form a second coating film. Next, the second coating film is dried to form a second laminated body consisting of a second adhesive layer 13 and a second release sheet. By attaching the second adhesive layer 13 of the second laminated body to the exposed surface of the substrate 11 in the first laminated body, a third laminated body formed by stacking a first release sheet, a first adhesive layer 12, a substrate 11, a second adhesive layer 13 and a second release sheet is formed. The release sheet in the third laminated body can be peeled off as a process material, or it can protect the adhesive layer until an adherend (for example, a semiconductor chip and a semiconductor wafer, etc.) is attached to the adhesive layer. As a variation of the third example, a method may be to form a first laminate consisting of a release sheet, a second adhesive layer 13 and a substrate, form a second laminate consisting of a release sheet and a first adhesive layer 12, and bond the first and second laminates together.

[0166] It should be noted that the order in which the first adhesive layer 12 and the second adhesive layer 13 are laminated on the substrate 11 is not particularly limited.

[0167] When the coating liquid contains a crosslinking agent, the (meth) acrylic copolymer (b1) in the coating film and the crosslinking agent can be crosslinked by changing the drying conditions of the coating film (e.g., temperature and time, etc.) or by performing a separate heat treatment, so as to form a crosslinked structure in the adhesive layer at a desired density. In order to allow the crosslinking reaction to proceed sufficiently, after laminating the first adhesive layer 12 and the second adhesive layer 13 on the substrate 11 by the above-mentioned method, the obtained adhesive sheet 10 can be conditioned by standing for several days in an environment of, for example, 23° C. and a relative humidity of 50%.

[0168] The thickness of the adhesive sheet 10 of the present embodiment is preferably 30 μm or more, and more preferably 50 μm or more. The thickness of the adhesive sheet 10 is preferably 400 μm or less, and more preferably 300 μm or less.

[0169] [How to use the adhesive sheet]

[0170] Since the adhesive sheet 10 of the present embodiment can be bonded to various adherends, there is no particular limitation on the adherend to which the adhesive sheet 10 of the present embodiment can be applied. For example, a semiconductor chip and a semiconductor wafer are preferred as the adherend.

[0171] The pressure-sensitive adhesive sheet 10 of this embodiment can also be suitably used in a sheet expanding method.

[0172] Specifically, there can be cited a sheet expansion method using an adhesive sheet 10, the sheet expansion method comprising: a bonding process of bonding a plurality of adherends to a first adhesive layer 12 or a second adhesive layer 13; a sheet expansion process of stretching the adhesive sheet 10 to expand the intervals between the plurality of adherends; and an energy ray irradiation process of irradiating the first adhesive layer 12 and the second adhesive layer 13 with energy rays to cure the first adhesive layer 12 and the second adhesive layer 13.

[0173] The sheet expanding method is preferably a method in which the plurality of adherends are bonded to the first adhesive layer 12 in a bonding step and the first and second adhesive layers 12 and 13 are cured by irradiating energy rays from the second adhesive layer 13 side in an energy ray irradiation step.

[0174] The pressure-sensitive adhesive sheet 10 of the present embodiment can be used, for example, in semiconductor processing applications.

[0175] Furthermore, the adhesive sheet 10 of the present embodiment can be used to increase the interval between a plurality of semiconductor chips bonded to one surface of the substrate 11 .

[0176] The above-mentioned wafer expansion method using the adhesive sheet 10 can also be applied to semiconductor processing. Specifically, when the adherend is a semiconductor chip or a semiconductor wafer, the wafer expansion method using the adhesive sheet 10 can be included as a step in the manufacturing method of a semiconductor device.

[0177] The expansion interval of the plurality of semiconductor chips depends on the size of the semiconductor chips and is not particularly limited. The adhesive sheet 10 is preferably used to expand the mutual spacing of adjacent semiconductor chips among the plurality of semiconductor chips attached to one side of the adhesive sheet 10 to more than 200 μm. It should be noted that there is no particular limit on the upper limit of the mutual spacing of the semiconductor chips. The upper limit of the mutual spacing of the semiconductor chips can be, for example, 6000 μm.

[0178] In addition, the adhesive sheet 10 of the present embodiment can also be used in the case where the interval between a plurality of semiconductor chips stacked on one side of the adhesive sheet 10 is widened by at least biaxial stretching. In this case, the adhesive sheet 10 is stretched by imparting tension along four directions of the +X axis direction, the -X axis direction, the +Y axis direction, and the -Y axis direction, for example, among the mutually orthogonal X axis and Y axis, and more specifically, is stretched along the MD direction and the CD direction of the substrate 11, respectively.

[0179] Such biaxial stretching can be performed, for example, using a separation device that applies tension in the X-axis direction and the Y-axis direction. Here, the X-axis and the Y-axis are orthogonal axes, one of the directions parallel to the X-axis is set as the +X-axis direction, the direction opposite to the +X-axis direction is set as the -X-axis direction, one of the directions parallel to the Y-axis is set as the +Y-axis direction, and the direction opposite to the +Y-axis direction is set as the -Y-axis direction.

[0180] The above-mentioned separation device applies tension to the adhesive sheet 10 in four directions, namely, the +X axis direction, the -X axis direction, the +Y axis direction, and the -Y axis direction. For each of the four directions, it is preferred to have a plurality of holding mechanisms and a plurality of tension applying mechanisms corresponding to these holding mechanisms. The number of holding mechanisms and tension applying mechanisms in each direction depends on the size of the adhesive sheet 10, and can be, for example, more than 3 and less than 10.

[0181] Here, for example, in a group including a plurality of holding mechanisms and a plurality of tension applying mechanisms provided in order to apply tension in the +X axis direction, it is preferred that each holding mechanism has a holding member for holding the adhesive sheet 10, and each tension applying mechanism moves the holding member corresponding to the tension applying mechanism in the +X axis direction to apply tension to the adhesive sheet 10. Furthermore, the plurality of tension applying mechanisms are each independently preferably provided in such a manner that the holding mechanism can be moved in the +X axis direction. In addition, in three groups including a plurality of holding mechanisms and a plurality of tension applying mechanisms provided in order to apply tension in the -X axis direction, the +Y axis direction, and the -Y axis direction, respectively, it is also preferred to have the same structure. Thus, the above-mentioned separation device can apply tensions of different sizes to the adhesive sheet 10 in each region in a direction orthogonal to each direction.

[0182] Generally, when the adhesive sheet 10 is held in four directions, namely, the +X axis direction, the -X axis direction, the +Y axis direction, and the -Y axis direction, by four holding members and stretched in the four directions, in addition to the four directions, tension is applied to the adhesive sheet 10 in the combined direction thereof (e.g., the combined direction of the +X axis direction and the +Y axis direction, the combined direction of the +Y axis direction and the -X axis direction, the combined direction of the -X axis direction and the -Y axis direction, and the combined direction of the -Y axis direction and the +X axis direction). As a result, a difference may occur between the intervals of the semiconductor chips in the inner region of the adhesive sheet 10 and the intervals of the semiconductor chips in the outer region.

[0183] However, in the above-mentioned separation device, in each direction of the +X axis direction, the -X axis direction, the +Y axis direction and the -Y axis direction, a plurality of tension applying mechanisms can independently apply tension to the adhesive sheet 10, and thus, the adhesive sheet 10 can be stretched in a manner that eliminates the difference in the interval between the inner side and the outer side of the above-mentioned adhesive sheet 10.

[0184] As a result, the interval between semiconductor chips can be accurately adjusted.

[0185] Figure 2 In the figure, a plan view of a sheet expanding device 100 is shown as an example of a sheet expanding device (separating device) capable of biaxial stretching. Figure 2 In the embodiment, the X-axis and the Y-axis are orthogonal to each other, the positive direction of the X-axis is set to the +X-axis direction, the negative direction of the X-axis is set to the -X-axis direction, the positive direction of the Y-axis is set to the +Y-axis direction, and the negative direction of the Y-axis is set to the -Y-axis direction. The adhesive sheet 10 can be arranged in the sheet expansion device 100 in such a way that each side is parallel to the X-axis or the Y-axis. As a result, the MD direction of the substrate 11 in the adhesive sheet 10 is parallel to the X-axis or the Y-axis. It should be noted that in Figure 2 In the figure, the adherend (semiconductor chip) is omitted.

[0186] like Figure 2 As shown, the sheet expansion device 100 has 5 holding mechanisms 101 in the +X axis direction, the -X axis direction, the +Y axis direction, and the -Y axis direction (a total of 20 holding mechanisms 101). Among the 5 holding mechanisms 101 in each direction, the holding mechanism 101A is located at both ends, the holding mechanism 101C is located in the center, and the holding mechanism 101B is located between the holding mechanism 101A and the holding mechanism 101C. Each side of the adhesive sheet 10 can be clamped by these holding mechanisms 101.

[0187] The film expansion device 100 has a plurality of tension-applying mechanisms (not shown) corresponding to each holding mechanism 101. By driving the tension-applying mechanisms, the holding mechanisms 101 can be moved independently of each other. For the five holding mechanisms 101 on one side of the +X-axis direction side of the clamped adhesive sheet 10, for example, they can be moved in the +X-axis direction at a first stretching speed for a given time. At the same time, among these five holding mechanisms 101, the holding mechanisms 101A and 101B can also be moved in a direction away from the holding mechanism 101C (i.e., the +Y-axis direction or the -Y-axis direction). At this time, the holding mechanism 101A can be moved at a speed slower than the first stretching speed (for example, 2 / 3 of the first stretching speed), and the holding mechanism 101B can be moved at a speed slower than the first stretching speed (for example, 1 / 3 of the first stretching speed). It should be noted that the holding mechanism 101C may not move in the +Y-axis direction and the -Y-axis direction. The holding mechanisms 101 located in the three directions other than the +X axis direction of the adhesive sheet 10 can also be moved in the same manner as in the +X axis direction, and the holding mechanisms 101A and 101B can be moved away from the holding mechanism 101C.

[0188] The above-mentioned separation device is preferably further provided with a measuring mechanism for measuring the mutual spacing of the semiconductor chips. Here, the above-mentioned tension applying mechanism is preferably arranged in a manner capable of individually moving the plurality of holding members based on the measurement result of the measuring mechanism. By providing the above-mentioned separation device with the measuring mechanism, the spacing can be further adjusted based on the measurement result of the semiconductor chip spacing obtained by the above-mentioned measuring mechanism, and as a result, the spacing of the semiconductor chips can be adjusted more accurately.

[0189] It should be noted that, in the above-mentioned detachment device, as a holding mechanism, for example, a chuck mechanism and a decompression mechanism can be cited. As a chuck mechanism, for example, a mechanical chuck and a chuck cylinder can be cited. As a decompression mechanism, for example, a decompression pump and a vacuum extractor can be cited. In addition, in the above-mentioned detachment device, as a holding mechanism, it can be a structure that supports the adhesive sheet 10 by an adhesive or magnetic force. In addition, as a holding member in the chuck mechanism, for example, a holding member having a lower supporting member that supports the adhesive sheet 10 from below, a driving device supported by the lower supporting member, and a holding member having a structure that is supported by the output shaft of the driven device and can press the adhesive sheet 10 from above by the driving of the driving device can be used. As the driving device, for example, an electric device and a transmission can be cited. As an electric device, for example: a rotary motor, a direct motor, a linear motor, a single-axis robot, and a multi-joint robot can be cited. As a transmission, for example: a cylinder, a hydraulic cylinder, a rodless cylinder, and a rotary cylinder can be cited.

[0190] In addition, in the above-mentioned separation device, the tension applying mechanism may have a driving device, and the holding member may be moved by the driving device. As the driving device provided by the tension applying mechanism, the same driving device as the driving device provided by the above-mentioned holding member may be used. For example, the tension applying mechanism may be a structure including a direct-acting motor as a driving device and an output shaft sandwiched between the direct-acting motor and the holding member, and the driven direct-acting motor may move the holding member via the output shaft.

[0191] When the adhesive sheet 10 of this embodiment is used to expand the interval between semiconductor chips, the interval can be expanded from a state where the semiconductor chips are in contact with each other, or from a state where the interval between the semiconductor chips is basically not expanded, or the interval between the semiconductor chips can be further expanded from a state where the interval between the semiconductor chips has been expanded to a given interval.

[0192] As a case where the interval between semiconductor chips is expanded from a state where the semiconductor chips are in contact with each other or from a state where the interval between semiconductor chips is not substantially expanded, for example, a semiconductor wafer may be divided on a dicing sheet to obtain a plurality of semiconductor chips, and then a plurality of semiconductor chips may be transferred from the dicing sheet to the adhesive sheet 10 of the present embodiment, and then the interval between the semiconductor chips may be expanded. Alternatively, a semiconductor wafer may be divided on the adhesive sheet 10 of the present embodiment to obtain a plurality of semiconductor chips, and then the interval between the semiconductor chips may be expanded.

[0193] In the case of further expanding the interval between semiconductor chips from a state where the interval between them has been expanded to a given interval, after expanding the interval between semiconductor chips to a given interval using another adhesive sheet, preferably the adhesive sheet 10 of the present embodiment, the semiconductor chips can be transferred from the adhesive sheet 10 to another adhesive sheet 10 of the present embodiment, and then the adhesive sheet 10 of the present embodiment is stretched, thereby further expanding the interval between the semiconductor chips. It should be noted that such transfer of semiconductor chips and stretching of adhesive sheets can be repeated multiple times until the interval between semiconductor chips reaches the desired distance.

[0194] [Method for manufacturing semiconductor device]

[0195] The method for manufacturing a semiconductor device according to the present embodiment preferably includes a sheet expanding method using the adhesive sheet 10 according to the present embodiment.

[0196] The method for manufacturing a semiconductor device of the present embodiment preferably includes a step (dicing step) of dicing a workpiece (semiconductor wafer) bonded to the dicing adhesive sheet to obtain a plurality of individual adherends (semiconductor chips). The dicing adhesive sheet preferably contains expandable fine particles.

[0197] In the laminating step of the semiconductor device manufacturing method of this embodiment, the first adhesive layer 12 or the second adhesive layer 13 of the adhesive sheet 10 is preferably laminated on the surface of the plurality of adherends (semiconductor chips) opposite to the surface in contact with the dicing adhesive sheet.

[0198] In the method for manufacturing a semiconductor device of the present embodiment, it is preferred to perform a step of separating the dicing adhesive sheet from a plurality of adherends (semiconductor chips) after the laminating step. When the dicing adhesive sheet contains expandable particles, it is preferred to expand the expandable particles to separate the plurality of adherends (semiconductor chips) attached to the adhesive sheet 10 from the dicing adhesive sheet.

[0199] In the method for manufacturing a semiconductor device according to the present embodiment, it is preferred that the sheet expanding step be performed after the dicing adhesive sheet is separated from the plurality of adherends (semiconductor chips).

[0200] The method for manufacturing a semiconductor device of the present embodiment preferably includes a step of transferring a plurality of adherends (semiconductor chips) to a second adhesive sheet having a second substrate and a third adhesive layer (transfer step). The second adhesive sheet preferably contains expandable fine particles.

[0201] In the method for manufacturing a semiconductor device of the present embodiment, it is preferred to adhere the third adhesive layer of the second adhesive sheet to the side of the plurality of adherends (semiconductor chips) opposite to the side in contact with the first adhesive layer 12 or the second adhesive layer 13, and separate the plurality of adherends (semiconductor chips) attached to the second adhesive sheet from the adhesive sheet 10. When the second adhesive sheet contains expandable particles, it is preferred to expand the expandable particles and separate the plurality of adherends (semiconductor chips) from the second adhesive sheet.

[0202] In addition, the adhesive sheet 10 of this embodiment is preferably used for applications requiring that the intervals between semiconductor chips be relatively large, and as an example of such an application, a method for manufacturing a fan-out semiconductor wafer-level package (FO-WLP) can be preferably cited. As an example of such a method for manufacturing a FO-WLP, the first embodiment is described below.

[0203] (First Embodiment)

[0204] Hereinafter, a first embodiment of a method for producing FO-WLP using the pressure-sensitive adhesive sheet 10 of the present embodiment will be described.

[0205] Figure 3A A semiconductor wafer W as a workpiece bonded to a dicing pressure-sensitive adhesive sheet A as a dicing sheet is shown.

[0206] The semiconductor wafer W has a circuit surface W1 on which a circuit W2 is formed. The dicing adhesive sheet A is attached to the back surface W3 of the semiconductor wafer W opposite to the circuit surface W1. The dicing adhesive sheet A has a substrate A1 and an adhesive layer A2. The adhesive layer A2 is laminated on the substrate A1.

[0207] [Cutting process]

[0208] Figure 3B The state where the plurality of semiconductor chips CP formed after dicing the semiconductor wafer W is held by the adhesive sheet A for dicing is shown.

[0209] The semiconductor wafer W held by the dicing adhesive sheet A is singulated by dicing to form a plurality of semiconductor chips CP (sometimes referred to as a dicing process). The semiconductor chip CP has a circuit surface W1 and a back surface W3 opposite to the circuit surface W1. A circuit W2 is formed on the circuit surface W1.

[0210] The cutting can be performed using a cutting mechanism such as a dicing saw.

[0211] Instead of using the cutting mechanism, dicing may be performed by irradiating laser light onto the semiconductor wafer W. For example, the semiconductor wafer W may be completely cut by irradiating laser light and separated into a plurality of semiconductor chips.

[0212] Alternatively, after forming a modified layer inside the semiconductor wafer W by irradiating a laser, the semiconductor wafer can be broken at the position of the modified layer by stretching the adhesive sheet in the expansion process described later, and singulated into semiconductor chips CP. Sometimes the method of singulating into semiconductor chips in this way is called stealth cutting. In the case of stealth cutting, the irradiation of the laser, for example, irradiates a laser in the infrared range in a manner focused on a focal point set inside the semiconductor wafer W. In addition, in these methods, the laser irradiation can be performed from any side of the semiconductor wafer W.

[0213] After dicing, the plurality of semiconductor chips CP are preferably transferred to the expansion sheet at a time.

[0214] The adhesive sheet A for cutting preferably includes expandable particles. In this case, at least any one of the substrate A1 and the adhesive layer A2 preferably includes expandable particles. The expandable particles are not particularly limited as long as they can expand themselves by external stimulation to form concavoconvex on the surface of the adhesive layer and reduce the adhesion to the adherend (semiconductor chip). As expandable particles, for example, heat-expandable particles that expand by heating, and energy-ray-expandable particles that expand by energy-ray irradiation, etc. can be cited. From the viewpoint of versatility and operability, as expandable particles, heat-expandable particles are preferably used.

[0215] The adhesive surface of the adhesive layer A2 can be formed with unevenness by expanding the expandable microparticles contained in the dicing adhesive sheet A, thereby reducing the contact area between the adhesive surface of the adhesive layer A2 and the semiconductor chip CP, thereby significantly reducing the adhesive force. As a result, when the dicing adhesive sheet A is separated from the semiconductor chip CP, there is no residual adhesive on the semiconductor chip CP, and the semiconductor chip CP can be easily separated from the dicing adhesive sheet A at one time while maintaining the cleanliness of the semiconductor chip CP.

[0216] [First transfer process]

[0217] Figure 3C The figure shows the process of transferring a plurality of semiconductor chips CP to the adhesive sheet 10 of this embodiment after the dicing process. This process is sometimes called a "transfer process", and in order to distinguish it from other transfer processes, it is sometimes called a "first transfer process".

[0218] (First bonding step)

[0219] The first transfer step includes a step of laminating the first adhesive layer 12 or the second adhesive layer 13 of the adhesive sheet 10 to the surface (circuit surface W1) opposite to the surface (back surface W3) of the plurality of semiconductor chips CP that is in contact with the dicing adhesive sheet A. This step is sometimes referred to as a "laminating step", and in order to distinguish it from other laminating steps, it is sometimes also referred to as a "first laminating step".

[0220] In the first embodiment, the first adhesive layer 12 is bonded to the circuit surfaces W1 of the plurality of semiconductor chips CP. It is preferable that the adhesive sheet 10 is bonded so that the first adhesive layer 12 covers the circuit surface W1.

[0221] The adhesive sheet 10 can be attached to the annular frame together with the plurality of semiconductor chips CP. In this case, the annular frame is placed on the first adhesive layer 12 of the adhesive sheet 10 and is lightly pressed to fix it. Then, the first adhesive layer 12 exposed on the inner side of the annular shape of the annular frame is pressed against the circuit surface W1 of the semiconductor chip CP to fix the plurality of semiconductor chips CP to the adhesive sheet 10.

[0222] (First separation step)

[0223] The first transfer step further includes a step of separating the dicing adhesive sheet A from the plurality of semiconductor chips CP after the above-mentioned bonding step. This step is sometimes referred to as a "separation step" and is sometimes referred to as a "first separation step" to distinguish it from other separation steps.

[0224] When the dicing adhesive sheet A is separated from the plurality of semiconductor chips CP after the adhesive sheet 10 is bonded, the back surfaces W3 of the plurality of semiconductor chips CP are exposed.

[0225] Figure 4A The plurality of semiconductor chips CP and the adhesive sheet 10 after the adhesive sheet A for dicing is separated are shown.

[0226] In the case where the dicing adhesive sheet A contains expandable particles, it is preferred to expand the expandable particles so as to separate the plurality of semiconductor chips CP attached to the adhesive sheet 10 from the dicing adhesive sheet A. By expanding the expandable particles contained in the dicing adhesive sheet A, it is possible to form unevenness on the adhesive surface of the adhesive layer A2, thereby reducing the contact area between the adhesive surface of the adhesive layer A2 and the semiconductor chip CP, and significantly reducing the adhesive force. As a result, the semiconductor chip CP can be easily separated from the dicing adhesive sheet A at one time without residual adhesive, etc., while maintaining the cleanliness of the semiconductor chip CP.

[0227] In the first embodiment, since the first adhesive layer 12 and the second adhesive layer 13 of the adhesive sheet 10 contain an energy-ray-curable adhesive, the expandable fine particles contained in the adhesive sheet A for dicing are preferably thermally expandable fine particles.

[0228] [Sheet expansion process]

[0229] Figure 4B A diagram illustrating a step of expanding the adhesive sheet 10 holding a plurality of semiconductor chips CP is shown. This step is sometimes referred to as a "sheet expanding step" and is sometimes referred to as a "first sheet expanding step" to distinguish it from other sheet expanding steps.

[0230] In this embodiment, the adhesive sheet 10 is used as an expansion sheet. In the expansion process, the adhesive sheet 10 is stretched to expand the intervals between the plurality of semiconductor chips CP. In addition, in the case of stealth dicing in the dicing process, by stretching the adhesive sheet 10, the semiconductor wafer can be broken at the position of the modified layer and singulated into a plurality of semiconductor chips CP, while the intervals between the plurality of semiconductor chips CP can be expanded.

[0231] The method of stretching the adhesive sheet 10 in the sheet expansion process is not particularly limited. As the method of stretching the adhesive sheet 10, for example, a method of stretching the adhesive sheet 10 by pressing a ring-shaped or circular expander, and a method of stretching the outer periphery of the adhesive sheet 10 by clamping a clamping member, etc. can be cited. As the latter method, a method of biaxial stretching using the above-mentioned separation device, etc. can be cited. Among these methods, from the viewpoint of being able to further expand the interval between the semiconductor chips CP, a method of biaxial stretching is preferably used.

[0232] like Figure 4B As shown, the distance between the semiconductor chips CP after the expansion is set to D1. The distance D1 depends on the size of the semiconductor chip CP and is not particularly limited. For example, the distance D1 is preferably 200 μm or more and 6000 μm or less, respectively.

[0233] [Energy ray irradiation process]

[0234] After the sheet expansion step, a step of irradiating the pressure-sensitive adhesive sheet 10 with energy rays to cure the first pressure-sensitive adhesive layer 12 and the second pressure-sensitive adhesive layer 13 is performed. This step may be referred to as an "energy ray irradiation step."

[0235] When the first adhesive layer 12 and the second adhesive layer 13 are UV-curable, the adhesive sheet 10 is irradiated with UV rays in the energy ray irradiation process. By curing the first adhesive layer 12 and the second adhesive layer 13 after the sheet expansion process, the shape retention of the stretched adhesive sheet 10 is improved. As a result, it is easy to maintain the uniformity of the plurality of semiconductor chips CP bonded to the first adhesive layer 12 and the second adhesive layer 13.

[0236] [Second transfer process]

[0237] Figure 5A A diagram is shown for explaining a process of transferring a plurality of semiconductor chips CP to the second adhesive sheet 20 after the sheet expansion process and the energy ray irradiation process. This process is sometimes referred to as a "transfer process" and is sometimes referred to as a "second transfer process" to distinguish it from other transfer processes.

[0238] The second transfer step includes a step of bonding the second adhesive sheet 20 to the plurality of semiconductor chips CP (a second bonding step) and a separation step of separating the adhesive sheet 10 (a second separation step) similarly to the first transfer step.

[0239] (Second Lamination Step)

[0240] In the second bonding step, the third adhesive layer 22 of the second adhesive sheet 20 is bonded to the back surfaces W3 of the plurality of semiconductor chips CP.

[0241] After the sheet expansion process and the energy ray irradiation process, the circuit surface W1 of the plurality of semiconductor chips CP is bonded toward the first adhesive layer 12. Therefore, the third adhesive layer 22 of the second adhesive sheet 20 is bonded to the back surface W3 opposite to the circuit surface W1. While maintaining the spacing between the plurality of semiconductor chips CP after the sheet expansion process, the second adhesive sheet 20 is preferably bonded to the back surface W3 of the semiconductor chip CP.

[0242] The second adhesive sheet 20 is not particularly limited as long as it can hold a plurality of semiconductor chips CP. In the first embodiment, the second adhesive sheet 20 including the second base material 21 and the third adhesive layer 22 is used.

[0243] The second adhesive sheet 20 preferably contains expandable fine particles, similar to the dicing adhesive sheet A. In this case, at least one of the second substrate 21 and the third adhesive layer 22 preferably contains expandable fine particles.

[0244] By expanding the expandable fine particles contained in the second adhesive sheet 20, the adhesive surface of the third adhesive layer 22 is formed with unevenness, thereby reducing the contact area between the adhesive surface of the third adhesive layer 22 and the semiconductor chip CP, thereby significantly reducing the adhesive force. As a result, when the second adhesive sheet 20 and the semiconductor chip CP are separated, there is no residual adhesive on the semiconductor chip CP, and the semiconductor chip CP can be easily separated from the second adhesive sheet 20 at one time while maintaining the cleanliness of the semiconductor chip CP.

[0245] The second adhesive sheet 20 can be attached to the second annular frame together with the plurality of semiconductor chips CP. In this case, the second annular frame is placed on the third adhesive layer 22 of the second adhesive sheet 20 and is lightly pressed to fix it. Then, the third adhesive layer 22 exposed to the inner side of the annular shape of the second annular frame is pressed against the back side W3 of the semiconductor chip CP to fix the plurality of semiconductor chips CP to the second adhesive sheet 20.

[0246] (Second separation step)

[0247] The second transfer step is a step of separating the adhesive sheet 10 after the second adhesive sheet 20 is bonded to the plurality of semiconductor chips CP.

[0248] Figure 5B The plurality of semiconductor chips CP and the second adhesive sheet 20 after the adhesive sheet 10 is separated are shown.

[0249] When the adhesive sheet 10 is separated, the circuit surfaces W1 of the plurality of semiconductor chips CP are exposed. After the sheet expansion step, the first adhesive layer 12 is cured, so the adhesive force of the first adhesive layer 12 is reduced, making it easier to peel the adhesive sheet 10 from the semiconductor chips CP.

[0250] It is preferable that after the adhesive sheet 10 is peeled off, the distance D1 between the plurality of semiconductor chips CP expanded in the chip expanding step is maintained.

[0251] [Third transfer process]

[0252] Figure 5C The figure shows a process of transferring the plurality of semiconductor chips CP bonded to the second adhesive sheet 20 to the third adhesive sheet 30. This process is sometimes referred to as a "transfer process" and is sometimes referred to as a "third transfer process" to distinguish it from other transfer processes.

[0253] The third transfer step includes a step of bonding the third adhesive sheet 30 to the plurality of semiconductor chips CP (third bonding step) and a step of separating the second adhesive sheet 20 (third separation step) similarly to the second transfer step.

[0254] It is preferable that the plurality of semiconductor chips CP transferred from the second adhesive sheet 20 to the third adhesive sheet 30 maintain a distance D1.

[0255] (Third Lamination Process)

[0256] In the third bonding step, the fourth adhesive layer 32 of the third adhesive sheet 30 is bonded to the circuit surfaces W1 of the plurality of semiconductor chips CP.

[0257] It is preferable that the third adhesive sheet 30 is bonded to the circuit surface W1 of the semiconductor chip CP in a state where the intervals between the plurality of semiconductor chips CP after the chip expansion step are maintained.

[0258] The third adhesive sheet 30 is not particularly limited as long as it can hold a plurality of semiconductor chips CP. The third adhesive sheet 30 includes a third base material 31 and a fourth adhesive layer 32 .

[0259] The third pressure-sensitive adhesive sheet 30 may contain expandable fine particles similar to the pressure-sensitive adhesive sheet A for dicing.

[0260] By expanding the expandable fine particles contained in the third adhesive sheet 30 to form unevenness on the adhesive surface of the fourth adhesive layer 32, the contact area between the adhesive surface of the fourth adhesive layer 32 and the semiconductor chip CP can be reduced, thereby significantly reducing the adhesive force. As a result, when the third adhesive sheet 30 is separated from the sealed body formed in the sealing step described later, no residual adhesive or the like is generated on the semiconductor chip CP, and the semiconductor chip CP can be separated from the third adhesive sheet 30 while maintaining the cleanliness of the semiconductor chip CP.

[0261] The expandable fine particles (third expandable fine particles) contained in the third adhesive sheet 30 , the expandable fine particles (first expandable fine particles) contained in the dicing adhesive sheet A, and the expandable fine particles (second expandable fine particles) contained in the second adhesive sheet 20 may be the same as or different from each other.

[0262] (Third Separation Step)

[0263] In the third separation step after the third bonding step, the second adhesive sheet 20 is separated from the plurality of semiconductor chips CP. When at least one of the second substrate 21 and the third adhesive layer 22 of the second adhesive sheet 20 contains expandable particles, the surface of the third adhesive layer 22 can be formed with unevenness by expanding the expandable particles, thereby facilitating the peeling of the second adhesive sheet 20 from the semiconductor chip CP.

[0264] In the case where both the second adhesive sheet 20 and the third adhesive sheet 30 contain expandable particles that expand due to the same external stimulus, when separating the second adhesive sheet 20, it is preferred to select the types and peeling methods of the second adhesive sheet 20 and the third adhesive sheet 30 so that the adhesive force of the fourth adhesive layer 32 of the third adhesive sheet 30 is greater than the adhesive force of the third adhesive layer 22 of the second adhesive sheet 20.

[0265] In addition, the mechanism for reducing the adhesive force of the second adhesive sheet 20 and the mechanism for reducing the adhesive force of the third adhesive sheet 30 are preferably different. For example, the substrate and the adhesive layer are preferably selected so that the adhesive force of the second adhesive sheet 20 is reduced by heat and the adhesive force of the third adhesive sheet 30 is reduced by ultraviolet rays.

[0266] When it is desired to seal the plurality of semiconductor chips CP on the third adhesive sheet 30 , it is preferable to use an adhesive sheet for a sealing step as the third adhesive sheet 30 , and it is more preferable to use an adhesive sheet having heat resistance.

[0267] When a heat-resistant adhesive sheet is used as the third adhesive sheet 30, the third substrate 31 and the fourth adhesive layer 32 are preferably formed of a heat-resistant material that can withstand the temperature applied in the sealing process. As another embodiment of the third adhesive sheet 30, an adhesive sheet having a third substrate, a third adhesive layer and a fourth adhesive layer can be cited. The adhesive sheet includes a third substrate between the third adhesive layer and the fourth adhesive layer, and has adhesive layers on both sides of the third substrate.

[0268] The plurality of semiconductor chips CP transferred from the second adhesive sheet 20 to the third adhesive sheet 30 are bonded together with the circuit surface W1 facing the fourth adhesive layer 32 .

[0269] [Sealing process]

[0270] Figure 5D 1 and 2 are diagrams for explaining a step of sealing a plurality of semiconductor chips CP using a sealing member 60. This step may be referred to as a "sealing step".

[0271] In the present embodiment, the sealing step is performed after the plurality of semiconductor chips CP are transferred to the third adhesive sheet 30 and the second adhesive sheet 20 is separated.

[0272] In the sealing process, the plurality of semiconductor chips CP are covered with the sealing member 60 while the circuit surface W1 is protected by the third adhesive sheet 30, thereby forming the sealed body 3. The sealing member 60 is also filled between the plurality of semiconductor chips CP. Here, since the circuit surface W1 and the circuit W2 are covered with the third adhesive sheet 30, the circuit surface W1 can be prevented from being covered with the sealing member 60.

[0273] The sealing step can obtain a sealed body 3 in which a plurality of semiconductor chips CP spaced at a predetermined distance are embedded in the sealing member 60. In the sealing step, the plurality of semiconductor chips CP are preferably covered by the sealing member 60 while maintaining the distance D1 after the chip expanding step.

[0274] After the sealing step, a separation step of separating the third adhesive sheet 30 from the sealed body 3 is performed. This step may be referred to as a fourth separation step.

[0275] When the third adhesive sheet 30 is separated, the circuit surface W1 of the semiconductor chip CP and the surface 3A of the sealing body 3 in contact with the third adhesive sheet 30 are exposed.

[0276] After the sheet expansion step, by repeating the transfer step and the sheet expansion step any number of times, the distance between the semiconductor chips CP can be set to a desired distance, and the circuit surface orientation when the semiconductor chips CP are sealed can be set to a desired orientation.

[0277] [Rewiring layer forming step and connecting step]

[0278] After the third adhesive sheet 30 is peeled off from the sealing body 3, a rewiring layer forming step of forming a rewiring layer electrically connected to the semiconductor chip CP and a connection step of electrically connecting the rewiring layer to the external terminal electrode are sequentially performed on the sealing body 3. The circuit of the semiconductor chip CP can be electrically connected to the external terminal electrode through the rewiring layer forming step and the connection step to the external terminal electrode.

[0279] [Singularization process]

[0280] The sealing body 3 connected to the external terminal electrodes is singulated as a semiconductor chip C unit. The method of singulating the sealing body 3 is not particularly limited. By singulating the sealing body 3, a semiconductor package of a semiconductor chip CP unit can be manufactured. The semiconductor package connected to the external electrodes outside the area fanned out to the semiconductor chip CP is manufactured as a fan-out wafer-level package (FO-WLP).

[0281] [Installation process]

[0282] In the present embodiment, it is preferable to include a step of mounting the individualized semiconductor packages on a printed wiring board or the like.

[0283] The adhesive sheet 10 of this embodiment is easy to maintain the shape of the state after the expansion process. Therefore, it can be suitably used for the use which needs to greatly expand the interval between a plurality of semiconductor chips and maintain the state of the sheet after expansion as described above.

[0284] [Variations of Embodiments]

[0285] The present invention is not limited to the above-described embodiment at all, and the present invention includes embodiments obtained by modifying the above-described embodiment, etc., within the scope that can achieve the object of the present invention.

[0286] The method for manufacturing the FO-WLP of the first embodiment described above may change some steps or omit some steps.

[0287] The circuits in the semiconductor wafer and semiconductor chip are not limited to the arrangement and shape shown in the figure. The connection structure with the external terminal electrodes in the semiconductor package is not limited to the method described in the above embodiment. In the above embodiment, the method of manufacturing a FO-WLP type semiconductor package is described as an example, but the present invention is also applicable to the method of manufacturing other semiconductor packages such as a fan-in WLP.

[0288] In the above embodiment, a method of bonding multiple adherends (semiconductor chips CP) to the first adhesive layer 12 is used as an example, but the present invention is not limited to such an embodiment. For example, a method of bonding multiple adherends (semiconductor chips CP) to the second adhesive layer 13 may also be used.

[0289] In the above-mentioned embodiment, the method of attaching the adherend (semiconductor chip CP) to the adhesive layer on the upper side of the adhesive sheet 10 and irradiating energy rays (ultraviolet rays) from the lower side of the adhesive sheet 10 is described as an example, but the present invention is not limited to such an embodiment. For example, the method of attaching the adherend (semiconductor chip CP) to the adhesive layer on the lower side of the adhesive sheet 10 and irradiating energy rays (ultraviolet rays) from the upper side of the adhesive sheet 10 may also be used.

[0290] The adhesive sheet is not limited to the mode described in the above-mentioned embodiment. As another mode of the adhesive sheet of the present invention, in the adhesive sheet, it is preferred that any layer in the first adhesive layer and the second adhesive layer is laminated with a coating. The adherend (semiconductor chip, etc.) is attached to the adhesive layer without a laminated coating.

[0291] Figure 6 An adhesive sheet 10A having a coating 14 is shown.

[0292] The material of the coating layer 14 is preferably a composition containing an energy-ray curable resin and an inorganic filler. As the energy-ray curable resin, for example, the above-mentioned energy-ray curable resin (a1) can be used. As the inorganic filler, for example, powders of silicon dioxide, aluminum oxide, talc, calcium carbonate, titanium dioxide, red iron, silicon carbide, and boron nitride, beads obtained by sphericalizing any of these powders, single crystal fibers, and glass fibers can be cited.

[0293] The thickness of the coating layer 14 is preferably 0.5 μm or more and 5 μm or less.

[0294] In the method for manufacturing a semiconductor device of the above embodiment, if the distance D1 between the plurality of semiconductor chips CP is to be further expanded after the sheet expansion process, a process of stretching the second adhesive sheet 20 (hereinafter sometimes referred to as the "second sheet expansion process") may be performed after the adhesive sheet 10 is peeled off. When the second sheet expansion process is performed, an expansion sheet is preferably used as the second adhesive sheet 20. As the expansion sheet, the adhesive sheet (first adhesive sheet) of the above embodiment is more preferably used.

[0295] In the second sheet expansion step, the intervals between the plurality of semiconductor chips CP are further expanded. The method of stretching the second adhesive sheet 20 in the second sheet expansion step is not particularly limited. For example, the second sheet expansion step may be performed in the same manner as the first sheet expansion step.

[0296] It should be noted that the distance between the semiconductor chips CP after the second chip expansion step is set to D2. The distance D2 is not particularly limited because it depends on the size of the semiconductor chip CP, but the distance D2 is greater than the distance D1. The distance D2 is preferably 200 μm or more and 6000 μm or less, for example, independently.

Claims

1. A film expansion method, the method comprising: A laminating step of laminating a plurality of adherends to the first adhesive layer or the second adhesive layer of the adhesive sheet; A sheet expansion step of expanding the adhesive sheet holding the plurality of adherends to expand the intervals between the plurality of adherends; as well as In an energy ray irradiation step after the sheet expansion step, the first adhesive layer and the second adhesive layer are irradiated with energy rays to cure the first adhesive layer and the second adhesive layer. The adhesive sheet has: a first adhesive layer containing a first energy ray-curable resin, a second adhesive layer containing a second energy ray-curable resin, and A substrate between the first adhesive layer and the second adhesive layer, The first adhesive layer is laminated on the first substrate surface of the substrate, and the second adhesive layer is laminated on the second substrate surface of the substrate.

2. The film expansion method according to claim 1, wherein: The first energy ray-curable resin is the same as the second energy ray-curable resin.

3. The film expansion method according to claim 1, wherein: The composition of the first adhesive layer is the same as that of the second adhesive layer.

4. The film expansion method according to claim 1, wherein: The thickness of the first adhesive layer is the same as the thickness of the second adhesive layer.

5. The film expansion method according to claim 1, wherein: In the laminating step, the plurality of adherends are laminated to the first adhesive layer. In the energy ray irradiation step, energy rays are irradiated from the second adhesive layer side to cure the first adhesive layer and the second adhesive layer.

6. The film expansion method according to claim 1, wherein: The adherend is a semiconductor chip.

7. A method for manufacturing a semiconductor device, comprising the wafer expansion method according to any one of claims 1 to 6, in, The manufacturing method includes the steps of dicing a workpiece adhered to a dicing adhesive sheet to obtain a plurality of individual adherends. In the laminating step, the first adhesive layer or the second adhesive layer of the adhesive sheet is laminated to a surface of the plurality of adherends opposite to a surface in contact with the adhesive sheet for dicing, After the laminating step, a step of separating the dicing pressure-sensitive adhesive sheet from the plurality of adherends is performed.

8. The method for manufacturing a semiconductor device according to claim 7, wherein: The sheet expanding step is performed after the dicing pressure-sensitive adhesive sheet is separated from the plurality of adherends.

9. The method for manufacturing a semiconductor device according to claim 7, wherein: The dicing adhesive sheet comprises expandable fine particles, In the step of separating the dicing pressure-sensitive adhesive sheet from the plurality of adherends, the expandable fine particles are expanded to separate the plurality of adherends bonded to the pressure-sensitive adhesive sheet from the dicing pressure-sensitive adhesive sheet.

10. The method for manufacturing a semiconductor device according to any one of claims 7 to 9, the method comprising: a second transfer step, after the sheet expansion step, transferring the plurality of adherends to a second adhesive sheet having a second substrate and a third adhesive layer; as well as A third transfer step is to transfer the plurality of adherends attached to the second adhesive sheet to a third adhesive sheet having a third substrate and a fourth adhesive layer. The third adhesive sheet comprises expandable fine particles, In the second transfer step, the third adhesive layer of the second adhesive sheet is attached to a surface of the plurality of adherends opposite to the surface in contact with the first adhesive layer or the second adhesive layer, and the adhesive sheet is separated from the plurality of adherends. In the third transfer step, the fourth adhesive layer of the third adhesive sheet is bonded to a surface of the plurality of adherends opposite to a surface in contact with the third adhesive layer, and the second adhesive sheet is separated from the plurality of adherends.

11. An adhesive sheet comprising: a first adhesive layer containing a first energy ray-curable resin, a second adhesive layer containing a second energy ray-curable resin, and A substrate between the first adhesive layer and the second adhesive layer, The first adhesive layer is laminated on the first substrate surface of the substrate, and the second adhesive layer is laminated on the second substrate surface of the substrate. The adhesive sheet is used in a sheet expansion method, which comprises the following steps: a laminating step of laminating a plurality of adherends to the first adhesive layer or the second adhesive layer of the adhesive sheet; a sheet expansion step of expanding the adhesive sheet holding the plurality of adherends to expand the intervals between the plurality of adherends; and In the energy ray irradiation step after the sheet expanding step, the first adhesive layer and the second adhesive layer are irradiated with energy rays to cure the first adhesive layer and the second adhesive layer.

12. The adhesive sheet according to claim 11, wherein The first energy ray-curable resin is the same as the second energy ray-curable resin.

13. The adhesive sheet according to claim 11, wherein The composition of the first adhesive layer is the same as that of the second adhesive layer.

14. The pressure-sensitive adhesive sheet according to any one of claims 11 to 13, wherein The thickness of the first adhesive layer is the same as the thickness of the second adhesive layer.

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