Cutting dicing-bonded integrated film, dicing-bonded film, and method for manufacturing semiconductor device

Abstract

Disclosed is a cutting grain-bonding integrated film. The cutting grain-bonding integrated film comprises a cutting tape having a base material and a pressure-sensitive adhesive layer provided on the base material, and a grain-bonding film disposed on the pressure-sensitive adhesive layer of the cutting tape. The grain-bonding film contains silver-containing particles that have been surface-treated with a saturated fatty acid. The content of the silver-containing particles is 75% by mass or more, based on the total amount of the grain-bonding film.

Description

Technical Field

[0001] This invention relates to a dicing / die-bonding integrated film, a die-bonding film, and a method for manufacturing a semiconductor device. Background Technology

[0002] Conventionally, semiconductor devices are manufactured through the following processes. First, a semiconductor wafer is attached to a pressure-sensitive adhesive sheet for dicing, and in this state, the semiconductor wafer is monolithically formed into a semiconductor chip (dicing process). Then, ultraviolet irradiation, pick-up, pressing, and die bonding processes are performed. Patent Document 1 discloses an adhesive sheet (dicing die bonding sheet) that simultaneously functions to fix the semiconductor wafer during the dicing process and to bond the semiconductor chip to the substrate during the die bonding process. In the dicing process, by monolithizing the semiconductor wafer and the adhesive layer, a chip with an adhesive sheet is obtained.

[0003] In recent years, devices called power semiconductor devices, used for power control and other applications, have become widespread. Power semiconductor devices are prone to generating heat due to the supplied current, requiring excellent heat dissipation. Patent Document 2 discloses a conductive film adhesive with higher heat dissipation after curing than before curing, and a slit tape with the film adhesive.

[0004] Previous technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2008-218571

[0007] Patent Document 2: Japanese Patent No. 6396189 Summary of the Invention

[0008] The technical problem to be solved by the invention

[0009] In developing a semiconductor device with excellent heat dissipation, the inventors used a die-bonding integrated film consisting of a pressure-sensitive adhesive layer and an adhesive layer formed from a die-bonding film containing silver particles in an amount sufficient for heat dissipation (e.g., 75% by mass or more based on the total amount of the die-bonding film). However, they found that the adhesion strength between the pressure-sensitive adhesive layer and the adhesive layer sometimes could not be sufficiently reduced after irradiation with ultraviolet light. If the adhesion strength between the pressure-sensitive adhesive layer and the adhesive layer was not sufficiently reduced, a defect sometimes occurred in the subsequent pick-up process where the chip with the adhesive layer could not be picked up from the pressure-sensitive adhesive layer.

[0010] Therefore, one objective of the present invention is to provide a grain-jointed integral film having a pressure-sensitive adhesive layer and an adhesive layer, which can sufficiently reduce the adhesion strength between the pressure-sensitive adhesive layer and the adhesive layer after irradiation with ultraviolet light.

[0011] means for solving technical problems

[0012] One aspect of the present invention relates to a diced grain bonding integrated film. This diced grain bonding integrated film comprises: a dicing strip having a substrate and a pressure-sensitive adhesive layer disposed on the substrate; and a grain bonding film disposed on the pressure-sensitive adhesive layer of the dicing strip. The grain bonding film contains silver-containing particles surface-treated with saturated fatty acids, and the content of the silver-containing particles is 75% by mass or more, based on the total amount of the grain bonding film. According to such a diced grain bonding integrated film, the adhesion strength between the pressure-sensitive adhesive layer and the adhesive layer after irradiation with ultraviolet light can be sufficiently reduced. According to the research of the present inventors, it is clearly known that when silver-containing particles surface-treated with unsaturated fatty acids are used, the adhesion strength between the pressure-sensitive adhesive layer and the adhesive layer cannot be sufficiently reduced, and tends to remain unchanged. This reason may not be clear, but for example, it can be considered that the unsaturated bonds of the unsaturated fatty acids react with the components of the pressure-sensitive adhesive layer through ultraviolet irradiation, making it difficult for the pressure-sensitive adhesive layer and the adhesive layer to separate. Therefore, it is speculated that by using silver-containing particles surface-treated with saturated fatty acids instead of unsaturated fatty acids, the reaction with the components of the pressure-sensitive adhesive layer can be suppressed, and the adhesion strength between the pressure-sensitive adhesive layer and the adhesive layer after ultraviolet irradiation can be sufficiently reduced. Furthermore, by using silver-containing particles surface-treated with saturated fatty acids, the compatibility of the adhesive layer with other resin components is improved, and the surface roughness (Ra) of the adhesive layer tends to improve. By improving the surface roughness (Ra) of the adhesive layer, the adhesion between the pressure-sensitive adhesive layer and the adhesive layer can be improved, for example, suppressing the defect of the chip with adhesive sheet detaching from the pressure-sensitive adhesive layer during the dicing process (chip detachment). Furthermore, there is a tendency for excellent wafer shear strength after the die bonding process.

[0013] Saturated fatty acids can have 8 to 20 carbon atoms. By using such fatty acids, the adhesion strength between the pressure-sensitive adhesive layer and the adhesive layer after exposure to ultraviolet light can be reduced more effectively.

[0014] Grain-bonded films may also contain thermosetting resins, curing agents, and elastomers. Grain-bonded films containing these components tend to have easily adjustable surface roughness (Ra).

[0015] Thermosetting resins may also contain epoxy resins that are liquid at 25°C. By including such epoxy resins in thermosetting resins, there is a tendency to easily obtain grain-bonded films with improved surface roughness (Ra).

[0016] Another aspect of the present invention relates to a method for manufacturing a semiconductor device. This method includes: a step of attaching a die bonding film of the aforementioned die-bonding integral film to a semiconductor wafer; a step of monolithizing the semiconductor wafer and the die bonding film; a step of irradiating a pressure-sensitive adhesive layer with ultraviolet light; a step of picking up a semiconductor chip with the die bonding film attached from a dicing tape; and a step of bonding the semiconductor chip to a support substrate with the die bonding film in between. According to this method for manufacturing a semiconductor device, since the aforementioned die-bonding integral film is used, a semiconductor device with excellent heat dissipation can be manufactured.

[0017] Another aspect of the invention relates to a grain bonding film. This grain bonding film contains silver-containing particles that have been surface-treated with saturated fatty acids. The content of the silver-containing particles is 75% by mass or more, based on the total amount of the grain bonding film.

[0018] Invention Effects

[0019] According to the present invention, a die-bonding integral film comprising a pressure-sensitive adhesive layer and an adhesive layer is disclosed, which can sufficiently reduce the adhesion strength between the pressure-sensitive adhesive layer and the adhesive layer after irradiation with ultraviolet light. Furthermore, according to the present invention, a method for manufacturing a semiconductor device using such a die-bonding integral film is provided. Moreover, according to the present invention, a die bonding film suitable for use with such a die-bonding integral film is provided. Attached Figure Description

[0020] Figure 1 This is a schematic cross-sectional view showing one embodiment of the grain bonding film.

[0021] Figure 2 This is a schematic cross-sectional view illustrating one embodiment of a grain-jointed integral film.

[0022] Figure 3 This is a schematic cross-sectional view illustrating one embodiment of a method for manufacturing a semiconductor device. Figure 3 (a), (b), (c), (d), (e), and (f) are schematic cross-sectional views representing each process.

[0023] Figure 4 This is a schematic cross-sectional view illustrating one embodiment of a semiconductor device. Detailed Implementation

[0024] Hereinafter, embodiments of the present invention will be described with appropriate reference to the accompanying drawings. However, the present invention is not limited to the following embodiments. In the following embodiments, except where specifically stated otherwise, the constituent elements (including steps, etc.) are not essential. The sizes of the constituent elements in each figure are conceptual sizes, and the relative sizes between the constituent elements are not limited to the relationships shown in the figures.

[0025] The numerical values ​​and their ranges used in this specification are the same and do not limit the invention. In this specification, the numerical range indicated by "~" represents the range encompassed by the values ​​before and after "~" as the minimum and maximum values, respectively. Within the numerical ranges described in stages in this specification, the upper or lower limit of one numerical range can be replaced by the upper or lower limit of another numerical range described in stages. Furthermore, within the numerical ranges described in this specification, the upper or lower limit of that numerical range can be replaced by the values ​​shown in the embodiments.

[0026] In this specification, (meth)acrylate refers to acrylate or its corresponding methacrylate. The same applies to other similar terms such as (meth)acryloyl, (meth)acrylic acid copolymer, etc.

[0027] [Grain bonding film]

[0028] Figure 1 This is a schematic cross-sectional view showing one embodiment of the grain bonding film. Figure 1 The grain bonding film 10 shown has a first surface 10A and a second surface 10B opposite to the first surface 10A. As described later, the first surface 10A can be a surface disposed on a pressure-sensitive adhesive layer of a cutting tape. Figure 1 As shown, the grain bonding film 10 can also be disposed on the support film 20. The grain bonding film 10 is thermosetting, and after a semi-cured (stage B) state, it can become a fully cured (stage C) state after curing treatment.

[0029] The grain bonding film 10 contains (a) silver particles surface-treated with saturated fatty acids, and may also contain (b) thermosetting resin, (c) curing agent and (d) elastomer, if needed.

[0030] (a) Composition: Silver-containing particles surface-treated with saturated fatty acids

[0031] (a) is a component used to improve the heat dissipation of the grain bonding film. The silver-containing particles ((a1) component) in (a) before surface treatment can be particles with silver on their surface, such as silver particles made of silver or silver-coated metal particles formed by coating the surface of metal particles (copper particles, etc.) with silver. Silver-coated metal particles can be, for example, silver-coated copper particles, etc. (a1) component can be silver particles made of silver.

[0032] Component (a) is obtained by surface-treating component (a1) with saturated fatty acids. Component (a1), for example, by surface-treating with fatty acids, can prevent particles from agglomerating. Furthermore, since component (a) is obtained by surface-treating component (a1) with saturated fatty acids instead of unsaturated fatty acids, it is presumed that it can suppress the reaction between the unsaturated bonds of the unsaturated fatty acids and the components of the pressure-sensitive adhesive layer. Therefore, it is believed that the adhesive strength between the pressure-sensitive adhesive layer and the adhesive layer after irradiation with ultraviolet light can be sufficiently reduced.

[0033] Examples of saturated fatty acids include caproic acid, enanthiacic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanic acid, stearic acid, nonadecanoic acid, icosanoic acid, icosanoic acid, icosanoic acid, tridecanoic acid, and icosanoic acid. Among these, the number of carbon atoms in saturated fatty acids can be, for example, 6 or more, 8 or more, 10 or more, 12 or more, 14 or more, or 16 or more, and can be 30 or less, 24 or less, 22 or less, or 20 or less. When the number of carbon atoms in saturated fatty acids is within such a range, the adhesion strength between the pressure-sensitive adhesive layer and the adhesive layer after irradiation with ultraviolet light can be reduced more sufficiently. Furthermore, the compatibility of the adhesive layer with other resin components is improved, the surface roughness (Ra) of the adhesive layer tends to be improved, and consequently, the wafer shear strength after the grain bonding process tends to be excellent.

[0034] There are no particular limitations on the method of surface treatment of component (a1) with saturated fatty acids, and conventionally known methods can be applied. For example, when manufacturing silver-containing particles using a liquid-phase reduction method with a reducing agent, the surface treatment of component (a1) can be performed using saturated fatty acids as a surface treatment agent (lubricant).

[0035] The shapes of components (a) and (a1) are not particularly limited; for example, they can be in the form of flakes, resin, or spheres. However, the shape of component (a) is preferably spherical. When component (a) is spherical, it tends to easily obtain a grain-bonded film with improved surface roughness (Ra). In addition, the shape of component (a) tends to maintain the shape of component (a1).

[0036] The average particle size of components (a) and (a1) can be 0.01 to 10 μm. When the average particle size of component (a) is 0.01 μm or more, it tends to prevent viscosity increase during the preparation of adhesive varnish, ensure the die bonding film contains the desired amount of component (a), and maintain better adhesion by ensuring the wettability of the die bonding film to the substrate. When the average particle size of component (a) is 10 μm or less, the film formability is better, and it tends to further improve heat dissipation by adding component (a). Furthermore, by setting it to this range, the thickness of the die bonding film can be made thinner, further enabling the stacking of semiconductor chip layers, and it tends to prevent chip cracks caused by component (a) protruding from the die bonding film. The average particle size of components (a) and (a1) can be 0.1 μm or more, 0.5 μm or more, 1.0 μm or more, or 1.5 μm or more, or 8.0 μm or less, 7.0 μm or less, 6.0 μm or less, 5.0 μm or less, 4.0 μm or less, or 3.0 μm or less. When the average particle size of component (a) is 5.0 μm or less, there is a tendency to easily obtain a grain-bonded film with improved surface roughness (Ra). Furthermore, the average particle size of component (a) refers to the particle size (D) when the ratio (volume fraction) relative to the total volume of component (a) is 50%. 50 (a) Average particle size of the component (D) 50 The average particle size of component (a1) can be determined by measuring the suspension of component (a1) in water using a laser scattering particle size analyzer (e.g., Microtrac). The average particle size of component (a1) has the same meaning as that of component (a) and can be determined using the same method. Furthermore, the average particle size of component (a) tends to maintain the average particle size of component (a1).

[0037] Components (a) and (a1) are spherical particles, and their average particle size is preferably less than 5.0 μm.

[0038] Based on the total amount of the grain bonding film, the content of component (a) is 75% by mass or more. When the content of component (a) is 75% by mass or more based on the total amount of the grain bonding film, the thermal conductivity of the grain bonding film can be improved, resulting in improved heat dissipation. Based on the total amount of the grain bonding film, the content of component (a) can also be 77% by mass or more, 80% by mass or more, 83% by mass or more, or 85% by mass or more. There is no particular upper limit to the content of component (a), and based on the total amount of the grain bonding film, it can be 98% by mass or less, 96% by mass or less, or 95% by mass or less.

[0039] (b) Composition: Thermosetting resin

[0040] (b) The component is a component that cures by forming three-dimensional bonds between molecules through heating or the like, and exhibits adhesive properties after curing. (b) The component may be an epoxy resin. (b) The component may also contain epoxy resin that is liquid at 25°C. Epoxy resins can be used without particular restriction as long as they are resins with epoxy groups within their molecules. Epoxy resins may have two or more epoxy groups within their molecules.

[0041] Examples of epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenolic varnish type epoxy resin, cresol varnish type epoxy resin, bisphenol A varnish type epoxy resin, bisphenol F varnish type epoxy resin, stilbene type epoxy resin, epoxy resin containing a triazine skeleton, epoxy resin containing a fluorene skeleton, tricresylmethane type epoxy resin, biphenyl type epoxy resin, xylylene type epoxy resin, biphenyl aralkyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, polyfunctional phenols, anthracene, and other polycyclic aromatic diglycidyl ether compounds. These can be used alone or in combination of two or more. From the viewpoint of the heat resistance of the cured product, the epoxy resin can be either a bisphenol type epoxy resin or a cresol varnish type epoxy resin.

[0042] Epoxy resins can also contain epoxy resins that are liquid at 25°C. By containing such epoxy resins, it is easier to obtain grain-bonded films with improved surface roughness (Ra). Commercially available epoxy resins that are liquid at 25°C include, for example, EXA-830CRP (trade name, manufactured by DIC Corporation) and YDF-8170C (trade name, NIPPON STEEL Chemical & Material Co., Ltd.).

[0043] There is no particular limitation on the epoxy equivalent of the epoxy resin, which can be 90–300 g / eq or 110–290 g / eq. When the epoxy equivalent of the epoxy resin is within such a range, it tends to maintain the bulk strength of the grain-bonded film and easily ensure the flowability of the adhesive composition when forming the grain-bonded film.

[0044] Based on the total amount of the grain bonding film, the content of component (b) can be 0.1% or more by mass, 1% or more by mass, 2% or more by mass, or 3% or more by mass, and can be less than 15% by mass, less than 12% by mass, less than 10% by mass, less than 8% by mass, or less than 6% by mass.

[0045] When component (b) contains epoxy resin that is liquid at 25°C, the mass ratio of the epoxy resin to component (b) (mass of the epoxy resin / total mass of component (b)) can be 10–100%, 40–100%, 60%–100%, or 80%–100% in percentage terms. When component (b) contains epoxy resin that is liquid at 25°C, the content of the epoxy resin, based on the total amount of the grain-bonded film, can be 0.1% or more by mass, 1% or more by mass, 2% or more by mass, or 3% or more by mass, and can be 15% or less by mass, 12% or less by mass, 10% or less by mass, 8% or less by mass, or 6% or less by mass.

[0046] (c) Ingredients: Curing agent

[0047] (c) The component can be a phenolic resin that can serve as a curing agent for epoxy resins. Phenolic resins can be used without particular restriction as long as they possess phenolic hydroxyl groups within their molecules. Examples of phenolic resins include phenolic varnish-type phenolic resins obtained by condensing or co-condensing phenolic compounds such as phenol, cresol, resorcinol, catechol, bisphenol A, bisphenol F, phenylphenol, and aminophenol, and / or naphthols such as α-naphthol, β-naphthol, and dihydroxynaphthol with aldehyde-containing compounds such as formaldehyde under an acidic catalyst; phenolic aralkyl resins synthesized from allylated bisphenol A, allylated bisphenol F, allylated naphthalene glycol, phenolic varnish, phenolic compounds and / or naphthols with dimethoxy-p-xylene or bis(methoxymethyl)biphenyl; naphthol aralkyl resins; biphenyl aralkyl-type phenolic resins; and phenyl aralkyl-type phenolic resins. These can also be used alone or in combination of two or more.

[0048] The hydroxyl equivalent of phenolic resin can be 40–300 g / eq, 70–290 g / eq, or 100–280 g / eq. When the hydroxyl equivalent of phenolic resin is above 40 g / eq, it tends to further increase the storage modulus of the membrane; when it is below 300 g / eq, it can prevent adverse conditions caused by foaming, gas release, etc.

[0049] From the viewpoint of curability, the ratio of the epoxy equivalent of component (b) to the hydroxyl equivalent of component (c) (epoxy equivalent of component (b) / hydroxyl equivalent of component (c)) can be 0.30 / 0.70 to 0.70 / 0.30, 0.35 / 0.65 to 0.65 / 0.35, 0.40 / 0.60 to 0.60 / 0.40, or 0.45 / 0.55 to 0.55 / 0.45. When this equivalent ratio is 0.30 / 0.70 or higher, there is a tendency to obtain more sufficient curability. When this equivalent ratio is 0.70 / 0.30 or lower, it is possible to prevent the viscosity from becoming too high and to obtain more sufficient flowability.

[0050] Based on the total amount of the grain bonding film, the content of component (c) can be more than 0.1% by mass, more than 0.5% by mass, more than 1% by mass or more than 2% by mass, and can be less than 15% by mass, less than 12% by mass, less than 10% by mass, less than 8% by mass or less than 6% by mass.

[0051] (d) Component: Elastomer

[0052] Examples of components (d) include polyimide resins, acrylic resins, polyurethane resins, polyphenylene ether resins, polyetherimide resins, phenoxy resins, and modified polyphenylene ether resins. Component (d) can be one of these resins, and can be a resin having crosslinking functional groups or an acrylic resin having crosslinking functional groups. Here, acrylic resin refers to a polymer containing structural units derived from (meth)acrylates. Acrylic resin can be a polymer containing structural units derived from (meth)acrylates having crosslinking functional groups such as epoxy groups, alcoholic hydroxyl groups, phenolic hydroxyl groups, or carboxyl groups as structural units. Furthermore, acrylic resin can also be an acrylic rubber, such as a copolymer of (meth)acrylate and acrylonitrile. These can be used alone or in combination of two or more.

[0053] Commercially available acrylic resins include, for example, SG-70L, SG-708-6, WS-023EK30, SG-280EK23, HTR-860P-3, HTR-860P-3CSP, and HTR-860P-3CSP-3DB (all manufactured by Nagase ChemteX Corporation).

[0054] (d) The glass transition temperature (Tg) of the component can be -50 to 50°C or -30 to 20°C. When the Tg of the acrylic resin is above -50°C, the tackiness of the grain-bonded film decreases, thus tending to further improve workability. When the Tg of the acrylic resin is below 50°C, there is a tendency to more adequately ensure the flowability of the adhesive composition when forming the grain-bonded film. Here, the glass transition temperature (Tg) of component (d) refers to the value measured using a DSC (Differential Scanning Calorimeter) (e.g., manufactured by Rigaku Corporation, trade name: Thermo Plus 2).

[0055] The weight-average molecular weight (Mw) of component (d) can be 50,000 to 1.6 million, 100,000 to 1.4 million, or 300,000 to 1.2 million. When the weight-average molecular weight of component (d) is 50,000 or higher, it tends to have better film-forming properties. When the weight-average molecular weight of component (d) is 1.6 million or lower, it tends to have better flowability of the adhesive composition when forming a grain-bonded film. Furthermore, the weight-average molecular weight (Mw) is a value measured using gel permeation chromatography (GPC) and converted from a calibration curve based on standard polystyrene.

[0056] (d) The measuring device and measuring conditions for the weight-average molecular weight (Mw) of the components are as follows.

[0057] Pump: L-6000 (manufactured by Hitachi, Ltd.)

[0058] Column: A column sequentially connecting gelpack GL-R440 (manufactured by Hitachi Chemical Co., Ltd.), gelpack GL-R450 (manufactured by Hitachi Chemical Co., Ltd.), and gelpack GL-R400M (manufactured by Hitachi Chemical Co., Ltd.) (each 10.7mm (diameter) × 300mm).

[0059] Eluent: Tetrahydrofuran (hereinafter referred to as "THF").

[0060] Sample: A solution in which 120 mg of the sample is dissolved in 5 mL of THF.

[0061] Flow rate: 1.75 mL / min

[0062] Based on the total amount of the grain bonding film, the content of component (d) can be more than 0.1% by mass, more than 0.5% by mass, more than 1% by mass, or more than 2% by mass, and can be less than 10% by mass, less than 8% by mass, less than 6% by mass, or less than 5% by mass.

[0063] The grain bonding film 10 may also contain (e) a curing accelerator.

[0064] (e) Ingredients: Curing accelerator

[0065] Grain-bonded films containing component (e) tend to further balance adhesion and bonding reliability. Examples of component (e) include imidazoles and their derivatives, organophosphorus compounds, secondary amines, tertiary amines, and quaternary ammonium salts. These can be used alone or in combination of two or more. From a reactivity point of view, component (e) can be imidazoles and their derivatives.

[0066] Examples of imidazoles include 2-methylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-cyanoethyl-2-methylimidazole. These can be used alone or in combination of two or more.

[0067] Based on the total amount of grain-bonded film, the content of component (e) can be 0.001 to 1% by mass. When the content of component (e) is within such a range, there is a tendency to further balance adhesion and connection reliability.

[0068] The grain-bonding film 10 may also contain coupling agents, antioxidants, rheology control agents, leveling agents, and other components besides components (a) to (e). Examples of coupling agents include γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, and 3-(2-aminoethyl)aminopropyltrimethoxysilane. The content of other components may be 0.01 to 3% by mass, based on the total amount of the grain-bonding film.

[0069] Figure 1 The grain bonding film 10 shown can be manufactured by forming an adhesive composition containing the above-mentioned component (a) (and, if necessary, components (b) to (e) and other components) into a film. Such a grain bonding film 10 can be formed by coating the adhesive composition onto a support film 20. The adhesive composition can be used as an adhesive varnish diluted with a solvent. When using an adhesive varnish, the grain bonding film 10 can be formed by coating the adhesive varnish onto the support film 20 and then heating and drying to remove the solvent.

[0070] There are no particular limitations on the solvent as long as it can dissolve the components other than (a). Examples of solvents include aromatic hydrocarbons such as toluene, xylene, mesitylene, cumene, and p-isopropyltoluene; aliphatic hydrocarbons such as hexane and heptane; cyclic alkanes such as methylcyclohexane; cyclic ethers such as tetrahydrofuran and 1,4-dioxane; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and 4-hydroxy-4-methyl-2-pentanone; esters such as methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, and γ-butyrolactone; carbonates such as ethylene carbonate and propylene carbonate; and amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone. These can be used alone or in combination of two or more. From the viewpoint of solubility and boiling point, solvents such as toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, or cyclohexanone can also be used. Based on the total mass of the adhesive varnish, the concentration of solid components in the adhesive varnish can be 10–80% by mass.

[0071] Adhesive varnishes can be prepared by mixing and kneading components (a) to (e), other components, and solvents. Furthermore, the order of mixing and kneading of the components is not particularly restricted and can be appropriately set. Mixing and kneading can be carried out using common dispersers such as mixers, mortar machines, three-roll mills, ball mills, and bead mills. After preparing the adhesive varnish, air bubbles can be removed by vacuum degassing or similar methods.

[0072] There are no particular limitations on the support film 20; for example, films made of polytetrafluoroethylene, polyethylene, polypropylene, polymethylpentene, polyethylene terephthalate, and polyimide can be used. The support film can also undergo a demolding process. The thickness of the support film 20 can be, for example, 10–200 μm or 20–170 μm.

[0073] As a method for applying adhesive varnish to the support film 20, known methods can be used, such as knife coating, roller coating, spray coating, gravure coating, bar coating, and curtain coating. The heating and drying conditions are not particularly limited as long as the solvent used is sufficiently evaporated; for example, it can be carried out at 50–200°C for 0.1–90 minutes.

[0074] The thickness of the die bonding film 10 can be appropriately adjusted according to the application, for example, it can be 3 to 200 μm. When the thickness of the die bonding film 10 is 3 μm or more, it tends to have sufficient adhesion strength to the semiconductor wafer, and when it is 200 μm or less, it tends to have sufficient heat dissipation. From the viewpoint of adhesion strength and thinning of semiconductor devices, the thickness of the die bonding film 10 can be 5 to 100 μm or 10 to 50 μm.

[0075] In the grain bonding film 10, the surface roughness of the first surface 10A can be, for example, 1.0 μm or less. Here, the first surface 10A is the surface disposed on the pressure-sensitive adhesive layer of the cutting strip (i.e., the surface of the grain bonding film 10 opposite to the surface that contacts the support film 20). Furthermore, in this specification, surface roughness refers to the arithmetic mean roughness Ra (JIS B0601-2001), which is a value calculated by the method described in the examples. Additionally, the measurement magnification can be 50 to 100 times.

[0076] From the viewpoint of preventing a decrease in adhesion caused by surface roughness, the surface roughness of the first surface 10A may be, for example, 0.9 μm or less, 0.8 μm or less, 0.7 μm or less, or 0.6 μm or less. From the viewpoint of preventing a decrease in anchoring effect caused by excessive surface smoothness, the surface roughness of the first surface 10A may be 0.1 μm or more, 0.2 μm or more, or 0.3 μm or more.

[0077] In the grain bonding film of the present invention, component (a) is surface-treated with saturated fatty acids instead of unsaturated fatty acids, thereby eliminating sites that react with the components of the pressure-sensitive adhesive layer. This suppresses the reaction with the components of the pressure-sensitive adhesive layer and sufficiently reduces the adhesion strength between the pressure-sensitive adhesive layer and the adhesive layer after UV irradiation. Therefore, the grain bonding film of the present invention can be combined with a cutting tape having a pressure-sensitive adhesive layer formed from a UV-curable pressure-sensitive adhesive and is suitable for cutting integral grain bonding films.

[0078] [Integrated membrane with grain cutting and bonding]

[0079] Figure 2 This is a schematic cross-sectional view illustrating one embodiment of a grain-jointed integral film. Figure 2 The die-cutting and bonding integrated film 100 shown includes: a cutting strip 50 having a substrate 40 and a pressure-sensitive adhesive layer 30 disposed on the substrate 40; and a die-cutting bonding film 10 disposed on the pressure-sensitive adhesive layer 30 of the cutting strip 50. The die-cutting bonding film 10 has a first surface 10A and a second surface 10B opposite to the first surface 10A. The die-cutting and bonding integrated film 100 may also have a support film 20 disposed on the second surface 10B of the die-cutting bonding film 100.

[0080] Examples of substrates 40 used on the cutting strip 50 include polytetrafluoroethylene film, polyethylene terephthalate film, polyethylene film, polypropylene film, polymethylpentene film, polyimide film, and other plastic films. Furthermore, the substrate 40 may undergo surface treatments such as primer coating, UV treatment, corona discharge treatment, grinding treatment, and etching treatment as needed.

[0081] The pressure-sensitive adhesive layer 30 can be a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive used in the cutting area, a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive, or a pressure-sensitive adhesive layer formed from a UV-curable pressure-sensitive adhesive. Since the aforementioned grain bonding film does not have sites that react with the components of the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer 30 can also be a pressure-sensitive adhesive layer formed from a UV-curable pressure-sensitive adhesive. When the pressure-sensitive adhesive layer 30 is formed from a UV-curable pressure-sensitive adhesive, it can have the property of reduced adhesiveness upon exposure to UV light. The case where the pressure-sensitive adhesive layer 30 is formed from a UV-curable pressure-sensitive adhesive will be described below.

[0082] The integrated die bonding membrane 100 can be manufactured by preparing a dicing strip 50 and a die bonding membrane 10, and attaching the first surface 10A of the die bonding membrane 10 to the pressure-sensitive adhesive layer 30 of the dicing strip 50.

[0083] In the integrated grain bonding membrane 100, based on the total amount of the grain bonding membrane, the grain bonding membrane 10 contains 75% by mass or more of component (a). The integrated grain bonding membrane with such a pressure-sensitive adhesive layer and adhesive layer exhibits excellent heat dissipation and can sufficiently reduce the adhesion strength between the pressure-sensitive adhesive layer and the adhesive layer after ultraviolet irradiation.

[0084] Manufacturing method of semiconductor devices (semiconductor packages)

[0085] Figure 3 This is a schematic cross-sectional view illustrating one embodiment of a method for manufacturing a semiconductor device. Figure 3 (a), (b), (c), (d), (e), and (f) are schematic cross-sectional views illustrating each process. The method for manufacturing a semiconductor device includes a process of attaching the die bonding film 10 (adhesive layer) (second surface 10B) of the aforementioned die bonding integral film 100 to a semiconductor wafer W (wafer lamination process, see reference). Figure 3 (a), (b)); The process of monolithizing the semiconductor wafer W and the die bonding film 10 (adhesive layer) (cutting process, see reference) Figure 3 (c)); The process of irradiating the pressure-sensitive adhesive layer 30 (within the substrate 40) with ultraviolet light (ultraviolet irradiation process, see reference). Figure 3 (d) The process of picking up the semiconductor chip Wa (semiconductor chip 60 with adhesive sheet) with the die bonding film 10a attached from the pressure-sensitive adhesive layer 30a (picking process, see reference). Figure 3 (e)); and the process of bonding the semiconductor chip 60 with the adhesive sheet to the support substrate 80 through the die bonding film 10a (semiconductor chip bonding process, see reference). Figure 3(f))).

[0086] <Wafer Lamination Process>

[0087] First, the die-bonding integrated film 100 is placed in a prescribed apparatus. Then, the second surface 10B of the die-bonding film 10 (adhesive layer) of the die-bonding integrated film 100 is attached to the surface Ws of the semiconductor wafer W (refer to...). Figure 3 (a) and (b)). The circuit surface of the semiconductor wafer W is preferably located on the side opposite to the surface Ws.

[0088] <Cutting Process>

[0089] Next, the semiconductor wafer W and the die bonding film 10 (adhesive layer) are cut (see reference). Figure 3 (c)). At this point, a portion of the pressure-sensitive adhesive layer 30 or all of the pressure-sensitive adhesive layer 30 and a portion of the substrate 40 can be cut. Thus, the cut grain bonding integral film 100 also functions as a cutting disc.

[0090] <Ultraviolet Irradiation Process>

[0091] Next, the pressure-sensitive adhesive layer 30 (within the substrate 40) is irradiated with ultraviolet light (reference). Figure 3 (d) Thus, the pressure-sensitive adhesive layer 30 cures, and the grain bonding film 10 (adhesive layer) no longer has sites that react with the components of the pressure-sensitive adhesive layer, thereby sufficiently reducing the adhesive strength between the pressure-sensitive adhesive layer 30 and the grain bonding film 10 (adhesive layer). For ultraviolet irradiation, ultraviolet light with a wavelength of 200–400 nm is preferably used. Regarding the ultraviolet irradiation conditions, the illuminance and irradiation dose are preferably adjusted to 30–240 mW / cm², respectively. 2 The range and 50~500mJ / cm 2 The range.

[0092] <Pickup Process>

[0093] Next, the cut semiconductor chips 60 with adhesive sheets are separated from each other by expanding the substrate 40, and the semiconductor chips 60 with adhesive sheets, which are lifted by the needle 72, are attracted from the substrate 40 side by the suction chuck 74 and picked up from the pressure-sensitive adhesive layer 30a (see reference). Figure 3(e) Furthermore, the semiconductor chip 60 with adhesive sheet has a semiconductor chip Wa and a die bonding film 10a. The semiconductor chip Wa is obtained by dicing a semiconductor wafer W into a single wafer, and the die bonding film 10a is obtained by dicing a die bonding film 10 into a single wafer. Additionally, the pressure-sensitive adhesive layer 30a is obtained by dicing a pressure-sensitive adhesive layer 30 into a single wafer. The pressure-sensitive adhesive layer 30a can remain on the substrate 40 when picking up the semiconductor chip 60 with adhesive sheet. While it may not be necessary to extend the substrate 40 during the picking process, extending the substrate 40 can further improve pickability.

[0094] The push amount of the needle 72 can be appropriately set. Furthermore, from the viewpoint of ensuring sufficient pick-up even for extremely thin wafers, for example, two or three stages of push-up can be performed. Moreover, semiconductor chips 60 with adhesive sheets can also be picked up using methods other than those using the suction chuck 74.

[0095] <Semiconductor chip bonding process>

[0096] After picking up the semiconductor chip 60 with the adhesive pad, the semiconductor chip 60 with the adhesive pad is bonded to the support substrate 80 through the die bonding film 10a by thermoforming (reference). Figure 3 (f) Alternatively, multiple semiconductor chips 60 with adhesive sheets can be bonded to the support substrate 80.

[0097] The manufacturing method of the semiconductor device may also include, as needed, a step of electrically connecting the semiconductor chip Wa to the support substrate 80 by wire bonding; and a step of sealing the semiconductor chip Wa with resin on the surface 80A of the support substrate 80 using a resin sealing material.

[0098] Figure 4 This is a schematic cross-sectional view illustrating one embodiment of a semiconductor device. Figure 4 The semiconductor device 200 shown can be manufactured through the above-described processes. In the semiconductor device 200, the semiconductor chip Wa and the support substrate 80 are electrically connected via wire bonding 70. The semiconductor device 200 can use a resin sealing material 92 to seal the semiconductor chip Wa onto the surface 80A of the support substrate 80. Solder balls 94 can also be formed on the side of the support substrate 80 opposite to the surface 80A for electrical connection with an external substrate (mother).

[0099] Example

[0100] The present invention will now be described with reference to embodiments, but the present invention is not limited to these embodiments.

[0101] <Preparation of Adhesive Varnish>

[0102] Using the symbols and composition ratios (parts by mass) shown in Table 1, cyclohexanone was added to epoxy resin (b) as a thermosetting resin, phenolic resin (c) as a curing agent, and acrylate rubber (d) as an elastomer, and the mixture was stirred to obtain a mixture. After the components dissolved, silver particles (a) surface-treated with saturated fatty acids were added to the mixture, and it was stirred using a dispersing blade to disperse the components until they were homogeneous. Then, curing accelerator (e) was added and dispersed until the components were homogeneous, thereby obtaining adhesive varnishes A to C with a solid content of 78% by mass.

[0103] In addition, the symbols for each component in Table 1 represent the following products.

[0104] (a) Silver-containing particles surface-treated with saturated fatty acids

[0105] • In SF134 Ag Flake (stearic acid) (manufactured by Ames Advanced Materials Corporation), silver particles surface-treated with stearic acid have the following shape: spherical, with an average particle size (50% of the laser particle size (D)). 50 )):2.2μm)

[0106] • In SF134 Ag Flake (decanoic acid) (manufactured by Ames Advanced Materials Corporation), silver particles surface-treated with decanoic acid have the following shape: spherical, with an average particle size (50% of the laser particle size (D)). 50 )):2.2μm)

[0107] (a') Silver-containing particles surface-treated with unsaturated fatty acids

[0108] ·AO-UCI-9 (trade name, silver-coated copper particles surface-treated with oleic acid, manufactured by DOWA Electronics Co., Ltd., shape: spherical, average particle size (laser 50% particle size (D) 50 )):2.3μm)

[0109] (b) Thermosetting resins

[0110] EXA-830CRP (trade name, manufactured by DIC Corporation, bisphenol-type epoxy resin, epoxy equivalent: 159 g / eq, liquid at 25°C)

[0111] (c) Curing agent

[0112] MEH-7800M (trade name, manufactured by MEIWA PLASTIC INDUSTRIES, LTD., phenolic resin, viscosity (150℃): 0.31~0.43 Pa·s (3.1~4.3 poise), hydroxyl equivalent: 175 g / eq)

[0113] (d) Elastomers

[0114] HTR-860P-3CSP (trade name, manufactured by Nagase ChemteX Corporation, glycidyl acrylate rubber, weight average molecular weight: 1 million, Tg: -7℃)

[0115] (e) Curing accelerator

[0116] ·2PZ-CN (trade name, manufactured by SHIKOKU CHEMICALS CORPORATION, 1-cyanoethyl-2-phenylimidazolium)

[0117] [Table 1]

[0118]

[0119] (Example 1)

[0120] <Fabrication of Grain Bonding Film>

[0121] Adhesive varnish A was used in the fabrication of the grain bonding film. Vacuum-defoamed adhesive varnish A was applied to a 38 μm thick polyethylene terephthalate (PET) film, which had undergone mold release treatment, serving as the support film. The applied varnish was then heated and dried in two stages at 90°C for 5 minutes, followed by 130°C for 5 minutes, to fabricate a 20 μm thick grain bonding film of Example 1 in stage B on the support film.

[0122] <Measurement of Surface Roughness>

[0123] The surface roughness of the first surface of the grain-bonded film (the surface opposite to the support film) was measured. The surface roughness (arithmetic mean roughness Ra, JIS B 0601-2001) was determined by measuring at 50x magnification using a shape measurement laser microscope VK-X100 (manufactured by KEYENCE CORPORATION). The results are shown in Table 2.

[0124] <Fabrication of a monolithic film with grain cutting and bonding>

[0125] A cutting tape (trade name: 6363-30, manufactured by Hitachi Chemical Co., Ltd.) having a substrate and a pressure-sensitive adhesive layer was prepared. The pressure-sensitive adhesive layer of the cutting tape was adhered to the grain bonding film of Example 1 using a rubber roller, thus producing a cutting-grain bonding integrated film of Example 1 having a substrate, a pressure-sensitive adhesive layer and an adhesive layer (grain bonding film) in sequence.

[0126] <Measurement of T-peel strength between pressure-sensitive adhesive layer and adhesive layer before and after UV irradiation>

[0127] The grain-bonding integrated membrane of Example 1 was prepared, and the T-peel strength between the pressure-sensitive adhesive layer and the adhesive layer was measured using this membrane. An Autograph EZ-S 50N (manufactured by SHIMADZU CORPORATION) was used for measurement. Easy-cut tape (manufactured by Oji Tac Co., Ltd.) was attached to the adhesive layer (grain bonding membrane) side of the grain-bonding integrated membrane, and the sample was obtained by cutting the grain-bonding integrated membrane to a size of 25 mm wide and 100 mm long. Using this sample, the T-peel strength between the pressure-sensitive adhesive layer and the adhesive layer before and after UV irradiation was measured at a clamping distance of 50 mm and a speed of 300 mm / min. A halogen lamp at 80 mW / cm² was used. 2 200mJ / cm 2 The material was irradiated with ultraviolet light under the specified conditions. Measurements were taken three times before and after ultraviolet irradiation, and the average of the three measurements was used as the peel strength. The results are shown in Table 2.

[0128] <Measurement of wafer shear strength>

[0129] A die-bonding integrated film of Example 1 was prepared. The support film of the die-bonding integrated film was peeled off, and the die bonding film (adhesive layer) of the die-bonding integrated film was attached to a 400 μm thick semiconductor wafer using a thin film laminator (manufactured by Teikoku Taping System Co., Ltd.) at 70°C, thereby obtaining a laminate. Next, the laminate was monolithically cut to a size of 5 mm × 5 mm to obtain a semiconductor chip with the die bonding film attached. The cutting was performed using a stepped cutting method with two blades, SD2000-FF and SD2000-EE. In the stepped cutting method, the first cut reached a depth of 200 μm on the semiconductor wafer, and the second cut reached a depth of 20 μm on the substrate of the cutting strip. The cutting conditions were set to a blade rotation speed of 4000 rpm and a cutting speed of 30 mm / s. Regarding the semiconductor chip with the attached die bonding film, a monolithic die bonding film with a semiconductor wafer was hot-pressed onto a lead frame at a temperature of 120°C, a pressure of 0.1 MPa, and a time of 5 seconds to obtain a sample. The sample was then heated at 110°C for 1 hour and then at 170°C for 3 hours to cure the die bonding film. The wafer shear strength was measured at 250°C using a universal bonding tester (trade name: Dage Series 4000, manufactured by ARCTEC, Inc.). The results are shown in Table 2.

[0130] (Example 2)

[0131] Except for the use of adhesive varnish B in the fabrication of the grain bonding film, the grain bonding film and the integrated grain-cutting bonding film of Example 2 were obtained in the same manner as in Example 1. For the grain bonding film and the integrated grain-cutting bonding film of Example 2, the surface roughness, the T-peel strength between the pressure-sensitive adhesive layer and the adhesive layer before and after ultraviolet irradiation, and the wafer shear strength were measured in the same manner as in Example 1. The results are shown in Table 2.

[0132] (Comparative Example 1)

[0133] Except for the use of adhesive varnish C in the fabrication of the die bonding film, the die bonding film and the die-cutting and bonding integrated film of Comparative Example 1 were obtained in the same manner as in Example 1. For the die bonding film and the die-cutting and bonding integrated film of Comparative Example 1, the surface roughness, the T-peel strength between the pressure-sensitive adhesive layer and the adhesive layer before and after ultraviolet irradiation, and the wafer shear strength were measured in the same manner as in Example 1. The results are shown in Table 2.

[0134] [Table 2]

[0135] project Example 1 Example 2 Comparative Example 1 Types of adhesive varnishes A B C Types of fatty acids stearic acid Decanoic acid Oleic acid Surface roughness Ra (μm) of the adhesive layer 0.4 0.5 0.7 T-shaped peel strength before UV irradiation (N / 25mm) 1.4 0.7 0.7 T-shaped peel strength after UV irradiation (N / 25mm) 0.3 0.1 0.8 Wafer shear strength (MPa) 2.3 1.6 0.4

[0136] As shown in Table 2, it is clearly evident that the integrated grain-jointing films of Examples 1 and 2, which contain silver particles surface-treated with saturated fatty acids, exhibit sufficiently low T-peel strength after ultraviolet irradiation, and consequently, sufficiently high wafer shear strength, compared to the integrated grain-jointing film of Comparative Example 1, which contains silver particles surface-treated with unsaturated fatty acids. These results confirm that the integrated grain-jointing film of the present invention, comprising a pressure-sensitive adhesive layer and an adhesive layer, can sufficiently reduce the adhesion strength between the pressure-sensitive adhesive layer and the adhesive layer after ultraviolet irradiation.

[0137] Symbol Explanation

[0138] 10-Die bonding film, 10A-First surface, 10B-Second surface, 10a-Die bonding film sheet, 20-Support film, 30-Pressure-sensitive adhesive layer, 40-Substrate, 50-Cut ribbon, 60-Semiconductor chip with adhesive sheet, 70-Wire bonding, 72-Pin, 74-Suction chuck, 80-Support substrate, 92-Resin sealant, 94-Solder ball, 100-Die bonding integrated film, 200-Semiconductor device.

Claims

1. A cutting-die-bonding integrated film comprising: a cutting tape having a base material and a pressure-sensitive adhesive layer provided on the base material; and a die-bonding film disposed on the pressure-sensitive adhesive layer of the cutting tape, wherein the pressure-sensitive adhesive layer is ultraviolet-curable, the die-bonding film contains silver-containing particles surface-treated with a saturated fatty acid, a thermosetting resin, and an elastomer, and the content of the silver-containing particles is 75% by mass or more, based on the total amount of the die-bonding film.

2. The cutting-die-bonding integrated film according to claim 1, wherein the number of carbon atoms of the saturated fatty acid is 8 to 20.

3. The cutting-die-bonding integrated film according to claim 1 or 2, wherein the die-bonding film further contains a curing agent.

4. The cutting-die-bonding integrated film according to claim 1 or 2, wherein the thermosetting resin contains an epoxy resin that is liquid at 25°C.

5. A method for manufacturing a semiconductor device, comprising: a step of attaching the die-bonding film of the cutting-die-bonding integrated film according to any one of claims 1 to 4 to a semiconductor wafer; a step of singulating the semiconductor wafer and the die-bonding film; a step of irradiating the pressure-sensitive adhesive layer with ultraviolet rays; a step of picking up a semiconductor chip to which a piece of the die-bonding film is attached from the cutting tape; and a step of adhering the semiconductor chip to a support substrate through the piece of the die-bonding film. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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