Method for manufacturing semiconductor device and adhesive film for processing semiconductor wafer

Abstract

A method for manufacturing a semiconductor device includes a step of attaching, from the adhesive layer side, a laminate including a back surface polishing tape including a base material and a pressure-sensitive adhesive layer formed on the base material, and a pressure-sensitive adhesive layer formed on the pressure-sensitive adhesive layer, on the side of a semiconductor wafer having a plurality of electrodes on one main surface, on which the electrodes are provided, and attaching, from the adhesive layer side, a laminate including a pressure-sensitive adhesive layer and a pressure-sensitive adhesive layer formed on the back surface polishing tape. The adhesive layer is formed on the pressure-sensitive adhesive layer; grinding the semiconductor wafer to thin the semiconductor wafer; cutting the thinned semiconductor wafer and the adhesive layer to singulate the semiconductor wafer and the adhesive layer into semiconductor chips with the adhesive layer; and electrically connecting the electrode of the semiconductor chip to which the adhesive layer has been attached to the electrode of another semiconductor chip or the electrode of the wiring circuit board, the semiconductor wafer and the laminate have a circular shape in plan view, and the diameter A of the semiconductor wafer and the diameter X of the laminate satisfy the relationship of formula (1) in plan view. (1) A < X < = A + 5mm.

Description

Technical Field

[0001] The invention relates to a method for manufacturing a semiconductor device and an adhesive film for semiconductor wafer processing. Background Art

[0002] Until now, the wire bonding method using fine metal wires such as gold wires has been widely used to connect semiconductor chips to substrates. However, in order to meet the requirements for high functionality, high integration, and high speed of semiconductor devices, the flip chip connection method (FC connection method) is becoming popular, which forms conductive protrusions called bumps on semiconductor chips or substrates to directly connect semiconductor chips to substrates.

[0003] As FC connection methods, there are known methods of metal bonding using solder, tin, gold, silver, copper, etc., methods of applying ultrasonic vibration to achieve metal bonding, methods of maintaining mechanical contact using the shrinkage force of resin, etc. However, from the perspective of the reliability of the connection part, the method of metal bonding using solder, tin, gold, silver, copper, etc. is generally used.

[0004] For example, in connection between a semiconductor chip and a substrate, a COB (Chip On Board) type connection method widely used in BGA (Ball Grid Array) and CSP (Chip Size Package) is also an FC connection method.

[0005] The FC connection method is also widely used in a COC (Chip On Chip) type connection method in which bumps or wirings are formed on a semiconductor chip to connect semiconductor chips (for example, refer to Patent Document 1).

[0006] Previous technical literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2008-294382 Summary of the invention

[0009] Technical issues to be solved by the invention

[0010] In the strong demand for further miniaturization, thinning, and high-functionality packaging, chip stacking packaging, POP (Package On Package), TSV (Through-Silicon Via), etc., which stack and multi-level the above-mentioned connection methods, have become widely popular.

[0011] The above technology is widely used because it can make the package smaller by configuring it in a three-dimensional shape rather than a flat shape. It is also effective in improving semiconductor performance and reducing noise, reducing mounting area, and saving power, and is attracting attention as the next-generation semiconductor wiring technology.

[0012] From the perspective of improving productivity, COW (Chip On Wafer), which is a method of manufacturing semiconductor packages by pressing (connecting) semiconductor chips on a wafer and then singulating them, and WOW (Wafer On Wafer), which is a method of manufacturing semiconductor packages by pressing (connecting) wafers to each other and then singulating them, are also attracting attention.

[0013] In the assembly of the flip chip package, first, an adhesive film for semiconductor wafer processing is attached to the side of the wafer where the electrode is provided. Then, the side of the wafer opposite to the side where the electrode is provided is ground to thin the wafer with the adhesive film for semiconductor wafer processing. Then, the thinned wafer with the adhesive film for semiconductor wafer processing is cut into individual semiconductor chips.

[0014] Then, the semiconductor chip is picked up by a clamp and supplied to the crimping tool via the clamp. Next, the chip-chip or chip-substrate is aligned and crimped. The temperature of the crimping tool is increased so that the metal of the upper and lower connecting parts or any of the upper and lower connecting parts reaches a melting point or above, thereby forming a metal bond. In the stacked and multi-level chip stacking package PKG, chip picking, alignment, and crimping are repeated.

[0015] In flip chip packaging, there is a trend towards miniaturization and thinning of the package, and semiconductor wafers and semiconductor chips are required to be further thinned. However, the thinner the thickness required for the semiconductor wafer and semiconductor chip is, the easier it is to cause a defect or crack in the semiconductor wafer during grinding when the wafer with the adhesive film for semiconductor wafer processing is thinned.

[0016] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a semiconductor device and an adhesive film for semiconductor wafer processing that can suppress the occurrence of chipping and cracking of a semiconductor wafer during grinding.

[0017] Means for solving technical problems

[0018] In order to solve the above-mentioned problems, the present invention provides the following method for manufacturing a semiconductor device and an adhesive film for semiconductor wafer processing.

[0019] [1] A method for manufacturing a semiconductor device, comprising the following steps: preparing a semiconductor wafer having a plurality of electrodes on one side of a main surface, attaching a laminate including a back grinding tape and an adhesive layer from the adhesive layer side to the side of the semiconductor wafer on which the electrodes are provided, the back grinding tape including a substrate and a pressure-sensitive adhesive layer formed on the substrate, the adhesive layer being formed on the pressure-sensitive adhesive layer; grinding the side of the semiconductor wafer opposite to the side on which the electrodes are provided to thin the semiconductor wafer; cutting the thinned semiconductor wafer and the adhesive layer to separate them into semiconductor chips with adhesive layers; and electrically connecting the electrodes of the semiconductor chip with adhesive layers to the electrodes of other semiconductor chips or wiring circuit boards, the semiconductor wafer and the laminate having a circular shape when viewed from above, and a diameter A of the semiconductor wafer and a diameter X of the laminate satisfying the relationship of the following formula (1) when viewed from above.

[0020] A<X≤A+5mm…(1)

[0021] [2] The method for manufacturing a semiconductor device according to [1], wherein the bonding force between the pressure-sensitive adhesive layer and the adhesive layer is lower than the bonding force between the adhesive layer and the semiconductor wafer.

[0022] [3] An adhesive film for semiconductor wafer processing, comprising a laminate including a back grinding tape and an adhesive layer, wherein the back grinding tape includes a substrate and a pressure-sensitive adhesive layer formed on the substrate, and the adhesive layer is formed on the pressure-sensitive adhesive layer, wherein the semiconductor wafer and the laminate have a circular shape when viewed from above, and when viewed from above, a diameter A of the semiconductor wafer and a diameter X of the laminate satisfy the relationship of the following formula (1).

[0023] A<X≤A+5mm…(1)

[0024] Effects of the Invention

[0025] According to the present invention, it is possible to provide a method for manufacturing a semiconductor device and an adhesive film for semiconductor wafer processing, which can suppress the occurrence of chipping and cracking of a semiconductor wafer during grinding. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic cross-sectional view showing one embodiment of the adhesive film for semiconductor wafer processing according to the present invention.

[0027] Figure 2 It is a top view showing one embodiment of the adhesive film for semiconductor wafer processing according to the present invention. DETAILED DESCRIPTION

[0028] In the following, preferred embodiments of the present invention are described in detail with reference to the accompanying drawings as appropriate. However, the present invention is not limited to the following embodiments. In addition, in the accompanying drawings, the same symbols are marked for the same or corresponding parts, and repeated descriptions are omitted. In addition, the positional relationship such as up, down, left, and right is based on the positional relationship shown in the accompanying drawings unless otherwise specified. Furthermore, the dimensional ratios of the accompanying drawings are not limited to the ratios shown in the drawings.

[0029] <Adhesive film for semiconductor wafer processing>

[0030] Figure 1 It is a schematic cross-sectional view showing one embodiment of the adhesive film for semiconductor wafer processing (hereinafter, also simply referred to as “adhesive film”) of the present invention. Figure 2 It is a top view showing one embodiment of the adhesive film for semiconductor wafer processing of the present invention. Figure 1 and Figure 2 The adhesive film 10 for semiconductor wafer processing shown in the figure is composed of a base film 1 and a laminate 6. The laminate 6 is composed of an adhesive layer 2 and a back grinding tape 5. The back grinding tape 5 is composed of a pressure-sensitive adhesive layer 3 and a base 4.

[0031] In the adhesive film 10 of this embodiment, Figure 2 As shown, the laminate 6 is pre-cut according to the shape of the semiconductor wafer to be attached so as to be circular in plan view. In the method for manufacturing a semiconductor device, the laminate 6 is peeled off from the base film 1 and attached to the main surface of the semiconductor wafer having a circular shape in plan view on the side where the electrode is provided. Here, the circular shape means that as long as it is roughly circular, it includes not only a perfect circle, but also a circle close to a perfect circle and a circle with a positioning cutout (orientation flat surface).

[0032] In the adhesive film 10 of the present embodiment, the diameter A (unit: mm) of the attached semiconductor wafer and the diameter (pre-cut diameter) X (unit: mm) of the laminate 6 satisfy the relationship of the following formula (1) in a plan view.

[0033] A<X≤A+5mm…(1)

[0034] By satisfying the above formula (1) with the diameter X of the stack 6, it is possible to suppress the generation of defects and cracks in the semiconductor wafer during grinding. Here, when X is less than A, a portion of the end of the main surface (attachment surface) of the wafer to which the stack 6 is attached will not be covered by the stack 6 and will be exposed. Moreover, when X is the same as A, as long as the attachment position of the stack 6 attached to the wafer is slightly offset, a portion of the end of the attachment surface of the wafer will not be covered by the stack 6 and will be exposed. Moreover, when the wafer is ground to be thinned, defects or cracks will occur at the end of the above-exposed attachment surface. In contrast, by making X greater than A, the exposure of the end of the above-exposed attachment surface can be suppressed, thereby suppressing the generation of defects or cracks in the wafer. From the perspective of more fully obtaining the above-mentioned effect, X can be greater than A+1mm, or greater than A+3mm. On the other hand, even if X exceeds A+5mm, the effect of suppressing the generation of defects or cracks on the wafer will not be further improved, so X is set to be less than A+5mm. Furthermore, by setting X to be less than or equal to A+5 mm, it is possible to suppress a decrease in workability due to the laminate 6 protruding from the wafer attachment surface being attached to the worktable of the device when laminating the laminate 6 or grinding the wafer.

[0035] Hereinafter, each layer constituting the adhesive film 10 of the present embodiment will be described in detail.

[0036] (Adhesive layer 2)

[0037] The adhesive layer can be formed using an adhesive composition. Although not particularly limited, the adhesive composition constituting the adhesive layer will be described below.

[0038] The adhesive composition contains, for example, (a) a resin having a weight average molecular weight of less than 10,000 (hereinafter referred to as "component (a)" as appropriate) and (b) a curing agent (hereinafter referred to as "component (b)" as appropriate).

[0039] If necessary, the adhesive composition may contain (c) a polymer component having a weight average molecular weight of 10,000 or more (hereinafter, referred to as "component (c)" as appropriate). If necessary, the adhesive composition may contain (d) a flux (hereinafter, referred to as "component (d)" as appropriate). If necessary, the adhesive composition may contain (e) a filler (hereinafter, referred to as "component (e)" as appropriate).

[0040] (a) Component: Resin with a weight average molecular weight of less than 10,000

[0041] The component (a) is not particularly limited, but is preferably a component that reacts with a curing agent. Components with a small molecular weight may decompose when heated and cause voids, so from the viewpoint of heat resistance, it is preferably reacted with a curing agent.

[0042] As (a) component, epoxy resin, acrylic resin, etc. are mentioned, for example.

[0043] The epoxy resin is not particularly limited as long as it has two or more epoxy groups in the molecule, and for example, bisphenol A type, bisphenol F type, naphthalene type, phenol novolac type, cresol novolac type, phenol aralkyl type, biphenyl type, triphenylmethane type, dicyclopentadiene type and various multifunctional epoxy resins can be used. These can be used alone or as a mixture of two or more.

[0044] The content of epoxy resin is, for example, 10 to 50% by mass based on the solid content of the adhesive composition. When the content is 10% by mass or more, the amount of curing component becomes sufficient, and the resin flow can be fully controlled after curing. When it is 50% by mass or less, the cured product does not become too hard, and there is a tendency to reduce the warping of the package.

[0045] In the present specification, "solid content" refers to non-volatile components other than volatile substances (water, solvent, etc.) contained in the adhesive composition, and also includes components that are liquid, syrupy, or waxy at room temperature (about 25°C).

[0046] The epoxy resin is preferably solid at room temperature (25° C.) Solids are less likely to produce voids than liquids, and the adhesive composition before curing (B stage) has low tack and is excellent in handling.

[0047] The acrylic resin is not particularly limited as long as it has one or more acryloyl groups in the molecule, and for example, bisphenol A type, bisphenol F type, naphthalene type, phenol novolac type, cresol novolac type, phenol aralkyl type, biphenyl type, triphenylmethane type, dicyclopentadiene type, fluorene type, adamantane type and various multifunctional acrylic resins can be used. These can be used alone or as a mixture of two or more.

[0048] The content of the acrylic resin is preferably 10 to 50% by mass, more preferably 15 to 40% by mass, based on the solid content of the adhesive composition. When the content is 10% by mass or more, the amount of the curing component becomes sufficient, and the resin flow can be fully controlled after curing. When it is 50% by mass or less, the cured product does not become too hard, and there is a tendency to reduce the warping of the package.

[0049] The acrylic resin is preferably solid at room temperature (25° C.) A solid state is less likely to produce voids than a liquid state, and the adhesive composition before curing (B stage) has low tack and is excellent in handling.

[0050] In acrylic resin, the number of functional groups of acryloyl groups is preferably 3 or less. If it is 3 or less, the number of functional groups will not become too many, and there is a tendency to easily cure in a short time and to easily increase the curing reaction rate. It is believed that this is because the number of functional groups becomes too many and the cured network proceeds rapidly, thereby being able to suppress the residue of unreacted groups.

[0051] (b) Component: Curing agent

[0052] Examples of the component (b) include phenol resin-based curing agents, acid anhydride-based curing agents, amine-based curing agents, imidazole-based curing agents, phosphine-based curing agents, azo compounds, and organic peroxides.

[0053] (i) Phenolic resin curing agent

[0054] As the phenolic resin curing agent, there is no particular limitation as long as it has two or more phenolic hydroxyl groups in the molecule, and for example, phenol novolac resin, cresol novolac resin, phenol aralkyl resin, cresol naphthol formaldehyde polycondensate, triphenylmethane type multifunctional phenolic resin and various multifunctional phenolic resins can be used. These can be used alone or as a mixture of two or more.

[0055] From the viewpoint of good curability, adhesion and storage stability, the equivalent ratio (phenolic hydroxyl group / epoxy group or acryloyl group, molar ratio) of the phenolic resin curing agent to the above-mentioned component (a) is preferably 0.3 to 1.5, more preferably 0.4 to 1.0, and further preferably 0.5 to 1.0. If the equivalent ratio is 0.3 or more, there is a tendency that the curability is improved and the adhesion is improved, and if it is 1.5 or less, there is a tendency that unreacted phenolic hydroxyl groups do not remain excessively, the water absorption is suppressed to a low level, and the insulation reliability is improved.

[0056] (ii) Acid anhydride curing agent

[0057] As the acid anhydride curing agent, for example, methylcyclohexanetetracarboxylic dianhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride and ethylene glycol bis-trimellitic anhydride ester can be used. These can be used alone or as a mixture of two or more.

[0058] From the viewpoint of good curability, adhesion and storage stability, the equivalent ratio (anhydride group / epoxy group or acryloyl group, molar ratio) of the acid anhydride curing agent to the above-mentioned component (a) is preferably 0.3 to 1.5, more preferably 0.4 to 1.0, and further preferably 0.5 to 1.0. If the equivalent ratio is 0.3 or more, there is a tendency that the curability is improved and the adhesion is improved, and if it is 1.5 or less, the unreacted acid anhydride will not remain excessively, the water absorption rate is suppressed to be low, and the insulation reliability tends to be improved.

[0059] (iii) Amine curing agent

[0060] As the amine-based curing agent, for example, dicyandiamide can be used.

[0061] From the viewpoint of good curability, adhesion and storage stability, the equivalent ratio (amine / epoxy or acryl group, molar ratio) of the amine curing agent to the above-mentioned component (a) is preferably 0.3 to 1.5, more preferably 0.4 to 1.0, and further preferably 0.5 to 1.0. If the equivalent ratio is 0.3 or more, there is a tendency for the curability to be improved and the adhesion to be improved, and if it is 1.5 or less, the unreacted amine will not remain excessively, and the insulation reliability tends to be improved.

[0062] (iv) Imidazole curing agent

[0063] Examples of the imidazole curing agent include 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyano-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2 '-Undecyl imidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole and adducts of epoxy resins and imidazoles. Among them, from the viewpoint of excellent curability, storage stability and connection reliability, 1-cyanoethyl-2-undecyl imidazole, 1-cyano-2-phenyl imidazole, 1-cyanoethyl-2-undecyl imidazole trimellitate, 1-cyanoethyl-2-phenyl imidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole and 2-phenyl-4-methyl-5-hydroxymethylimidazole are preferred. These can be used alone or in combination of two or more. Furthermore, a latent curing agent obtained by microencapsulating these substances can also be used.

[0064] The content of the imidazole curing agent is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, relative to 100 parts by mass of component (a). If the content of the imidazole curing agent is 0.1 parts by mass or more, there is a tendency for the curability to be improved, and if it is 20 parts by mass or less, there is a tendency that the adhesive layer will not be cured before the metal bonding is formed, and poor connection is not likely to occur.

[0065] (v) Phosphine-based curing agent

[0066] Examples of the phosphine-based curing agent include triphenylphosphine, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra(4-methylphenyl)borate, and tetraphenylphosphonium (4-fluorophenyl)borate. These can be used alone or in combination of two or more.

[0067] The content of the phosphine curing agent is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, relative to 100 parts by mass of component (a). If the content of the phosphine curing agent is 0.1 parts by mass or more, there is a tendency for the curability to be improved, and if it is 10 parts by mass or less, there is a tendency that the adhesive layer will not cure before the metal bonding is formed, and poor connection is less likely to occur.

[0068] Phenolic resin curing agents, acid anhydride curing agents and amine curing agents can be used alone or as a mixture of two or more. Imidazole curing agents and phosphine curing agents can be used alone or together with phenolic resin curing agents, acid anhydride curing agents or amine curing agents.

[0069] (vi) Organic peroxides

[0070] As organic peroxide, for example, ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxydicarbonate, peroxyester etc. are enumerated. From the viewpoint of storage stability, hydroperoxide, dialkyl peroxide, peroxyester are preferably used. Furthermore, from the viewpoint of heat resistance, hydroperoxide and dialkyl peroxide are preferably used. These can be used alone or in combination of two or more.

[0071] The content of the organic peroxide is preferably 0.5 to 10 parts by mass, more preferably 1 to 5 parts by mass, relative to 100 parts by mass of the component (a). When the content of the organic peroxide is 0.5 parts by mass or more, sufficient curing is easily performed, and when it is 10 parts by mass or less, there is a tendency that the molecular chain becomes shorter or unreacted groups remain due to rapid curing, thereby reducing reliability.

[0072] The combination of component (a) and curing agent (i) to (vi) is not particularly limited as long as curing is performed. However, from the viewpoints of operability, storage stability, and curability, the epoxy resin may be phenol and imidazole, acid anhydride and imidazole, amine and imidazole, or imidazole alone. Since productivity is improved when connected in a short time, imidazole alone with excellent rapid curing properties may be used. Since volatile components such as low molecular weight components can be suppressed during curing in a short time, the generation of voids can also be suppressed. From the viewpoints of operability and storage stability, the acrylic resin may be an organic peroxide.

[0073] The curing reaction rate may be 80% or more or 90% or more. If the curing reaction rate at 200°C (below the solder melting temperature) / 5s is 80% or more, there is a tendency that the solder is less likely to flow or scatter during connection (above the solder melting temperature), thereby causing poor connection and poor insulation reliability.

[0074] The curing system can be a free radical polymerization system. For example, as a resin with a weight average molecular weight of less than 10,000, compared with an anionic polymerization epoxy resin (epoxy-curing agent curing system), an acrylic resin (acrylic acid-peroxide curing system) of free radical polymerization is preferred. The curing reaction rate of the acrylic curing system (free radical polymerization system) is higher, so it is easier to suppress the gap, thereby more easily suppressing the flow and scattering of the metal in the connecting part. If it contains an anionic polymerization epoxy resin, the curing reaction rate is sometimes not easy to reach more than 80%. When epoxy resin is used simultaneously, the epoxy resin can be less than 20 parts by mass relative to 80 parts by mass of acrylic resin. The acrylic curing system can also be used alone.

[0075] (c) Component: a polymer component having a weight average molecular weight of 10,000 or more

[0076] As (c) component, epoxy resin, phenoxy resin, polyimide resin, polyamide resin, polycarbodiimide resin, cyanate resin, acrylic resin, polyester resin, polyethylene resin, polyethersulfone resin, polyetherimide resin, polyvinyl acetal resin, carbamate resin, acrylic rubber etc. can be enumerated. About (c) component, from the viewpoint of excellent heat resistance and film formation, epoxy resin, phenoxy resin, polyimide resin, acrylic resin, acrylic rubber, cyanate resin, polycarbodiimide resin etc. can be mentioned, from the viewpoint of further excellent heat resistance and film formation, epoxy resin, phenoxy resin, polyimide resin, acrylic resin, acrylic rubber can be mentioned. These polymer components can be used alone, and can also be used as a mixture or copolymer of more than two kinds.

[0077] The mass ratio of the component (c) to the epoxy resin as the component (a) is not particularly limited. From the viewpoint of maintaining the film shape, the epoxy resin may be 0.01 to 5 parts by mass, 0.05 to 4 parts by mass, or 0.1 to 3 parts by mass relative to 1 part by mass of the component (c). If the amount of the epoxy resin relative to 1 part by mass of the component (c) is 0.01 parts by mass or more, there is a tendency for the curability to be improved and the adhesive force to be improved, and if it is 5 parts by mass or less, there is a tendency for the film-forming property to be improved.

[0078] The mass ratio of the component (c) to the acrylic resin as the component (a) is not particularly limited, and the acrylic resin may be 0.01 to 10 parts by mass, 0.05 to 5 parts by mass, or 0.1 to 5 parts by mass relative to 1 part by mass of the component (c). If the amount of the acrylic resin relative to 1 part by mass of the component (c) is 0.01 parts by mass or more, there is a tendency for the curability to be improved and the adhesive force to be improved, and if it is 10 parts by mass or less, there is a tendency for the film-forming property to be improved.

[0079] From the viewpoint of excellent adhesion of the adhesive layer to the substrate and the semiconductor chip, the glass transition temperature (Tg) of the component (c) may be below 120°C, below 100°C or below 85°C. If Tg is below 120°C, there is a tendency that bumps formed on the semiconductor chip, electrodes and wiring patterns formed on the substrate, etc. are easily buried through the adhesive layer, and the generation of voids caused by residual bubbles is easily suppressed. In addition, the above Tg refers to the Tg measured using DSC (e.g., manufactured by PerkinElmer Co., Ltd., trade name "DSC-7") under the conditions of a sample amount of 10 mg, a heating rate of 10°C / min, and a measurement atmosphere of air.

[0080] The weight average molecular weight of component (c) is 10,000 or more in terms of polystyrene conversion, but in order to show good film forming properties alone, it can be 30,000 or more, 40,000 or more, or 50,000 or more. When the weight average molecular weight is 10,000 or more, there is a tendency for film forming properties to be improved. In addition, in this specification, the weight average molecular weight refers to the weight average molecular weight when measured in terms of polystyrene conversion using high performance liquid chromatography (e.g., manufactured by Shimadzu Corporation., trade name "C-R4A").

[0081] (d) Ingredients: Flux

[0082] The adhesive composition may contain a fluxing agent, i.e., a fluxing activator, which is a compound showing fluxing activity (activity of removing oxides and impurities). As component (d), nitrogen-containing compounds having lone electron pairs such as imidazoles and amines, carboxylic acids, phenols, and alcohols can be cited. In addition, organic acids such as carboxylic acids show stronger fluxing activity than alcohols, and connectivity is improved.

[0083] (e) Ingredients: Filler

[0084] The adhesive composition may contain a filler in order to control the viscosity and physical properties of the cured product, and to suppress the generation of voids when connecting semiconductor chips to each other or to connect a semiconductor chip to a substrate and to suppress moisture absorption.

[0085] As the component (e), inorganic fillers, whiskers, resin fillers, etc. can be mentioned. The inorganic filler can be an insulating inorganic filler. The component (e) can be used alone or as a mixture of two or more. There is no particular limitation on the shape, particle size and blending amount of the component (e).

[0086] Examples of the insulating inorganic filler include fillers composed of glass, silica, alumina, titanium oxide, carbon black, mica, boron nitride, etc. Among them, silica, alumina, titanium oxide, boron nitride, etc. are preferred, and silica, alumina, and boron nitride are more preferred.

[0087] Examples of the whiskers include whiskers composed of aluminum borate, aluminum titanate, zinc oxide, calcium silicate, magnesium sulfate, boron nitride, and the like.

[0088] Examples of the resin filler include fillers composed of polyurethane resin, polyimide resin, methyl methacrylate resin, methyl methacrylate-butadiene-styrene copolymer resin (MBS), and the like.

[0089] From the viewpoint of improving dispersibility and adhesion, component (e) may be a surface treated filler. Examples of surface treatments include glycidyl (epoxy), amine, phenyl, phenylamine, acrylic, methacrylic, vinyl, and silane surface treatments. The physical properties of component (e) may be appropriately adjusted by the above surface treatments.

[0090] In view of the ease of surface treatment, the component (e) may be a filler subjected to a silane-based surface treatment. Examples of the silane-based surface treatment include epoxy silane-based, amino silane-based, and acrylic silane-based surface treatments.

[0091] From the viewpoint of dispersibility, fluidity and adhesiveness, the component (e) may be a filler subjected to a glycidyl-based, aniline-based, acrylic-based or methacrylic-based surface treatment. Also, from the viewpoint of storage stability, the component (e) may be a filler subjected to a phenyl-based, acrylic-based or methacrylic-based surface treatment.

[0092] Regarding the particle size of the component (e), the average particle size is preferably 1.5 μm or less from the viewpoint of preventing biting during flip chip connection, and is more preferably 1.0 μm or less from the viewpoint of visibility (transparency). In addition, the average particle size of the component (e) is the particle size corresponding to the point of 50% volume when the cumulative frequency distribution curve based on the particle size is obtained with the total volume of the particles as 100%, and can be measured by a particle size distribution measuring device using a laser diffraction scattering method, etc.

[0093] Compared with inorganic fillers, resin fillers can impart flexibility at high temperatures such as 260° C., and are therefore suitable for improving reflow resistance. In addition, resin fillers can impart flexibility, and are also effective in improving film formability.

[0094] From the viewpoint of insulation reliability, the component (e) preferably has insulating properties. The adhesive composition may not contain conductive metal fillers such as silver fillers and solder fillers.

[0095] Based on the solid content of the adhesive composition as a whole, the content of component (e) is preferably 30 to 90% by mass, and more preferably 40 to 80% by mass. If the content of component (e) is 30% by mass or more, the heat dissipation is high, and there is a tendency to suppress the generation of voids and moisture absorption. If the content of component (e) is 90% by mass or less, there is a tendency to suppress the decrease in the fluidity of the adhesive composition due to increased viscosity and the generation of the filler biting (sinking) into the connection portion, thereby suppressing the decrease in connection reliability.

[0096] In addition to the above-mentioned components (a) to (e), the adhesive composition may also contain additives such as ion trapping agents, antioxidants, silane coupling agents, titanium coupling agents, and leveling agents. These may be used alone or in combination of two or more. The content of the additives may be appropriately adjusted to demonstrate the effects of each additive.

[0097] The adhesive layer 2 can be formed by dissolving or dispersing the adhesive composition containing the above-mentioned components in a solvent to prepare a varnish, applying the varnish on the base film 1, and removing the solvent by heating.

[0098] Examples of a method for applying the varnish onto the base film 1 include generally known methods such as a doctor blade coating method, a roll coating method, a spray coating method, a gravure coating method, a bar coating method, and a curtain coating method.

[0099] The temperature conditions for removing the solvent by heating are preferably about 70 to 150°C.

[0100] The solvent used is not particularly limited, but is preferably determined from the boiling point in consideration of volatility when the adhesive layer is formed. Specifically, from the perspective of difficulty in curing the adhesive layer when the adhesive layer is formed, preferably a solvent with a relatively low boiling point such as methanol, ethanol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, methyl ethyl ketone, acetone, methyl isobutyl ketone, toluene, and xylene. In addition, for the purpose of improving coating properties, a solvent with a relatively high boiling point such as dimethylacetamide, dimethylformamide, N-methylpyrrolidone, and cyclohexanone can be used. These solvents can be used alone or in combination of two or more.

[0101] The thickness of the adhesive layer 2 may be 2 to 50 μm, or 5 to 20 μm. From the viewpoint of suppressing the resin overflow after mounting, the thickness may be 5 to 16 μm.

[0102] (Base film 1)

[0103] The substrate film is not particularly limited as long as it has heat resistance that can withstand the heating conditions when drying the organic solvent. Examples of the substrate film include polyolefin films such as polypropylene films and polymethylpentene films, polyester films such as polyethylene terephthalate films and polyethylene naphthalate films, polyimide films, polyetherimide films, etc. The substrate film may be a single monolayer film or a multilayer film formed by combining two or more.

[0104] (Back grinding tape 5)

[0105] The back grinding tape 5 including the substrate 4 and the pressure-sensitive adhesive layer 3 formed on the substrate 4 can be formed using a known back grinding tape used when grinding a semiconductor wafer. Although not particularly limited, the back grinding tape will be described below.

[0106] The substrate 4 is not particularly limited, and a known substrate can be used. The substrate 4 is preferably a resin film, for example. The resin film can be, for example, a polyethylene terephthalate film, a polyethylene naphthalate film, a polybutylene terephthalate film, a polypropylene film, a polyimide film, a polyetherimide film, a polyphenylene sulfide film, a polyarylate film, etc. The substrate 4 is preferably a polyester film, and more preferably a polyethylene terephthalate film.

[0107] The thickness of the substrate 4 can be appropriately selected within a range that does not impair workability. The thickness of the substrate 4 may be 200 μm or less, 10 to 150 μm, or 20 to 100 μm.

[0108] As the pressure-sensitive adhesive layer 3, there is no particular limitation, and a known pressure-sensitive adhesive layer can be used. As the pressure-sensitive adhesive layer 3, at least one selected from the group consisting of a compound having a diol group, an isocyanate compound, a urethane (meth) acrylate compound, a diamine compound, a urea methacrylate compound, and a high-energy ray-polymerizable copolymer having an ethylenically unsaturated group on a side chain can be used. The pressure-sensitive adhesive layer 3 is preferably composed of a component whose adhesiveness is not easily changed by a storage environment such as temperature, humidity, storage period, and the presence or absence of oxygen, and more preferably composed of a component whose adhesiveness does not change due to a storage environment.

[0109] Furthermore, the pressure-sensitive adhesive layer 3 may also contain components that are cured by high-energy rays such as ultraviolet rays and radiation or by heat. Among these components, components that are cured by high-energy rays are preferred, and components that are cured by ultraviolet rays are more preferred. When the pressure-sensitive adhesive layer 3 contains components that are cured by high-energy rays such as ultraviolet rays and radiation or by heat, the adhesive force of the pressure-sensitive adhesive layer 3 can be reduced by curing treatment.

[0110] The adhesive film 10 can be obtained by laminating the base film 1 and the adhesive layer 2 to the back grinding tape 5 and then pre-cutting the adhesive layer 2 and the back grinding tape 5 to form a laminate 6. The lamination and pre-cutting can be performed by a known method.

[0111] In the adhesive film 10, the adhesive force between the pressure-sensitive adhesive layer 3 and the adhesive layer 2 is preferably lower than the adhesive force between the adhesive layer 2 and the attached semiconductor wafer. This makes it easy to peel the back grinding tape 5 from the adhesive layer 2 after grinding the semiconductor wafer.

[0112] (Method for manufacturing semiconductor device)

[0113] The method for manufacturing a semiconductor device according to the present embodiment includes the following steps: preparing a semiconductor wafer having a plurality of electrodes on one side of a main surface, attaching the laminate 6 in the adhesive film 10 for semiconductor wafer processing from the adhesive layer 2 side on the side of the semiconductor wafer on which the electrodes are provided; grinding the side of the semiconductor wafer opposite to the side on which the electrodes are provided to thin the semiconductor wafer; cutting the thinned semiconductor wafer and the adhesive layer 2 to separate them into semiconductor chips with adhesive layers; and electrically connecting the electrodes of the semiconductor chips with adhesive layers to the electrodes of other semiconductor chips or wiring circuit boards. Here, the semiconductor wafer and the laminate 6 have a circular shape in a plan view, and in a plan view, the diameter A of the semiconductor wafer and the diameter X of the laminate 6 satisfy the relationship of the following formula (1). The relationship between X and A can be as described in the description of the adhesive film 10 for semiconductor wafer processing.

[0114] A<X≤A+5mm…(1)

[0115] The laminate 6 can be attached to the semiconductor wafer by, for example, heat pressing, roll lamination, vacuum lamination, etc. The thickness of the adhesive layer 2 in the laminate 6 can be appropriately set according to the size of the semiconductor chip or the wiring circuit board and the height of the bump (electrode).

[0116] Regarding the attachment of the stack 6 to the semiconductor wafer, the stack 6 can be peeled off from the base film 1 in the adhesive film 10 for semiconductor wafer processing and the peeled stack 6 can be attached to the semiconductor wafer, but it is also possible to prepare a stack 6 without the base film 1 and directly attach the stack 6 to the semiconductor wafer.

[0117] Next, the semiconductor wafer with the laminated body is ground on the side opposite to the side provided with the electrode to thin the semiconductor wafer. The semiconductor wafer after thinning can have a thickness of 30 to 300 μm.

[0118] Then, the back grinding tape 5 is peeled off from the thinned semiconductor wafer with an adhesive layer. Next, the semiconductor wafer with an adhesive layer is diced to separate the semiconductor wafer into semiconductor chips, thereby manufacturing semiconductor chips with an adhesive layer attached (semiconductor chips with an adhesive layer).

[0119] After dicing, the semiconductor chip with the adhesive layer is picked up and crimped onto the wiring circuit board. The crimping is performed using a crimping device such as a flip chip bonder at a temperature above the melting point of the solder bump to form a metal joint at the connection. The heat treatment can also be performed using a hot crimping machine, a reflow furnace, a pressurized oven, etc. After the above steps, a semiconductor device can be manufactured.

[0120] As mentioned above, although the preferred embodiment of the present invention was described, the present invention is not limited to the above-mentioned embodiment.

[0121] Example

[0122] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the Examples.

[0123] The compounds used in each of the Examples and Comparative Examples are as follows.

[0124] (a) Resins with a weight average molecular weight of less than 10,000

[0125] (a-1) a trisphenol methane skeleton-containing multifunctional epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name "EP1032H60", weight average molecular weight: 800 to 2000)

[0126] (a-2) Bisphenol F type liquid epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name "YL983U", weight average molecular weight: about 340)

[0127] (b) Curing agent

[0128] 2,4-Diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct (manufactured by SHIKOKU CHEMICALS CORPORATION, trade name "2MAOK-PW")

[0129] (c) a polymer component having a weight average molecular weight of 10,000 or more

[0130] Phenoxy resin (manufactured by TOHTO Chemical Industry Co., Ltd., trade name "ZX1356", Tg: about 71° C., weight average molecular weight: about 63,000)

[0131] (d) Flux (carboxylic acid)

[0132] Glutaric acid (melting point: about 95°C)

[0133] (e) Filling

[0134] (e-1) Silica filler (manufactured by Admatechs Co., Ltd., trade name "SE2050", average particle size: 0.5 μm)

[0135] (e-2) Methacrylic acid surface treated nano-silica filler (manufactured by Admatechs Co., Ltd., trade name "YA050C-SM", average particle size: about 50 nm)

[0136] (e-3) Resin filler (manufactured by Dow Chemical Japan Ltd., trade name "EXL-2655", core-shell type organic fine particles)

[0137] (Examples 1 to 3 and Comparative Examples 1 to 2)

[0138] <Preparation of adhesive layer>

[0139] An organic solvent (cyclohexanone) was added to the components (a), (b), (c), (d) and (e) in the mass ratios shown in Table 1 so that the NV value ([mass of varnish after drying] / [mass of varnish before drying]×100) became 60 mass%. Then, an organic solvent (cyclohexanone) having the same mass as the total amount of the components (a) to (e) and the organic solvent was added. The mixture was stirred for 30 minutes using a ball mill (planetary micro-pulverizer P-7 manufactured by Fritsch Japan Co., Ltd.) with zirconia beads. After stirring, the zirconia beads were removed by filtration to prepare a coating varnish.

[0140] [Table 1]

[0141]

[0142] The obtained coating varnish was applied onto a base film (manufactured by Toyobo Film Solution Co., Ltd., trade name “Purex A55”) using a small precision coating device (Yasui Seiki Inc.) and dried at 100° C. for 5 minutes to form an adhesive layer having a thickness of 20 μm.

[0143] <Production of back grinding tape>

[0144] An acrylic copolymer using 2-ethylhexyl acrylate and methyl methacrylate as main monomers and hydroxyethyl acrylate and acrylic acid as functional monomers was obtained by solution polymerization. The synthesized acrylic copolymer had a weight average molecular weight of 400,000 and a glass transition point of -38°C. A polyfunctional isocyanate crosslinking agent (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "Coronate HL") was mixed with 100 parts by mass of the acrylic copolymer to prepare a varnish for a pressed adhesive.

[0145] The above-mentioned varnish for pressure-sensitive adhesive was applied to a polyethylene terephthalate (PET) substrate (manufactured by UNITIKA LTD., trade name "EMBLET S25") having a thickness of 25 μm using an applicator, with the gap adjusted so that the thickness of the pressure-sensitive adhesive layer after drying would be 20 μm, and dried at 80° C. for 5 minutes. Thus, a back grinding tape having a pressure-sensitive pressure-sensitive adhesive layer formed on the substrate was obtained.

[0146] <Manufacturing of adhesive films for semiconductor wafer processing>

[0147] Next, a back grinding tape was attached to the surface of the adhesive layer on the opposite side of the substrate film under the conditions of 50°C, a linear pressure of 3 kgf, and a speed of 5 m / min, thereby obtaining an adhesive film for semiconductor wafer processing having a laminated structure of substrate film / adhesive layer / pressure-sensitive adhesive layer / substrate.

[0148] In the obtained multilayer film, Figure 2As shown, the back grinding tape and the adhesive layer (layer other than the base film) are pre-cut in a manner such that they have a circular shape having a diameter (pre-cut diameter) shown in Table 2 when viewed from above, thereby obtaining adhesive films for semiconductor wafer processing of Examples 1 to 3 and Comparative Examples 1 to 2 having a pre-cut stack.

[0149] [Evaluation of Defects and Cracks in Semiconductor Wafers]

[0150] The laminate was peeled off from the adhesive film obtained in the embodiment and the comparative example, and the adhesive layer side of the laminate was attached to the surface of a silicon wafer (diameter 300 mm, thickness 775 μm) using a vacuum laminator (manufactured by Nikko-Materials Co., Ltd., trade name "V130") under the conditions of diaphragm temperature: 80°C, worktable temperature: 40°C, pressure: 0.5 MPa, and pressing time: 60 seconds.

[0151] The silicon wafer to which the laminate was attached was ground from the side opposite to the side to which the laminate was attached using a back grinder (manufactured by DISCO Corporation, trade name "DGP8761"). Grinding was performed using a grindstone with a grit size of #340 to a finishing thickness Z1 shown in Table 2, and then using a grindstone with a grit size of #6000 to a finishing thickness Z2 shown in Table 2. After grinding, the laminate was visually checked for adhesion to the worktable of the back grinder, and no adhesion was found in either the Example or the Comparative Example.

[0152] After grinding, the wafer surface was observed with an optical microscope to confirm whether there were defects and cracks at the wafer end. The case where neither defects nor cracks occurred was evaluated as "A", and the case where at least one of defects and cracks occurred was evaluated as "B". The results are shown in Table 2.

[0153] [Table 2]

[0154]

[0155] Explanation of symbols

[0156] 1-substrate film, 2-adhesive layer, 3-pressure-sensitive adhesive layer, 4-substrate, 5-back grinding tape, 6-laminated body, 10-adhesive film for semiconductor wafer processing.

Claims

1. A method for manufacturing a semiconductor device, comprising the following steps: A semiconductor wafer having a plurality of electrodes on one side of a main surface is prepared, and a laminate including a back grinding tape and an adhesive layer is attached from the adhesive layer side to the side of the semiconductor wafer on which the electrodes are provided, wherein the back grinding tape includes a substrate and a pressure-sensitive adhesive layer formed on the substrate, and the adhesive layer is formed on the pressure-sensitive adhesive layer; Grinding the semiconductor wafer on a side opposite to the side on which the electrode is provided to thin the semiconductor wafer; Cutting the thinned semiconductor wafer and the adhesive layer to separate them into semiconductor chips with adhesive layers; and The electrodes of the semiconductor chip with the adhesive layer are electrically connected to the electrodes of other semiconductor chips or wiring circuit boards. The semiconductor wafer and the stacked body have a circular shape in a plan view, When viewed from above, the diameter A of the semiconductor wafer and the diameter X of the stack satisfy the following relationship (1): A<X≤A+5mm…(1).

2. The method for manufacturing a semiconductor device according to claim 1, wherein: The adhesive force between the pressure-sensitive adhesive layer and the adhesive layer is lower than the adhesive force between the adhesive layer and the semiconductor wafer.

3. An adhesive film for semiconductor wafer processing, comprising a laminate including a back grinding tape and an adhesive layer, wherein the back grinding tape includes a substrate and a pressure-sensitive adhesive layer formed on the substrate, and the adhesive layer is formed on the pressure-sensitive adhesive layer, wherein: The semiconductor wafer and the stacked body have a circular shape in a plan view, When viewed from above, the diameter A of the semiconductor wafer and the diameter X of the stack satisfy the following relationship (1): A<X≤A+5mm…(1).

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