JP7622368B2 - Dicing/die bonding integrated film, die bonding film, and method for manufacturing semiconductor device - Google Patents

Description

This disclosure relates to an integrated dicing and die bonding film, a die bonding film, and a method for manufacturing a semiconductor device.

Conventionally, semiconductor devices are manufactured through the following steps. First, a semiconductor wafer is attached to a dicing adhesive sheet, and in this state, the semiconductor wafer is diced into semiconductor chips (dicing step). Then, a pick-up step, a pressure bonding step, a die bonding step, and the like are performed. Patent Document 1 discloses an adhesive sheet (dicing die bonding sheet) that has both the function of fixing the semiconductor wafer in the dicing step and the function of adhering the semiconductor chip to a substrate in the die bonding step. In the dicing step, the semiconductor wafer and the adhesive layer are diced into individual chips with adhesive pieces attached.

In recent years, devices known as power semiconductor devices that perform functions such as controlling electric power have become widespread. Power semiconductor devices tend to generate heat due to the current supplied to them, and so excellent heat dissipation is required. Patent Document 2 discloses a conductive film-like adhesive and a dicing tape with a film-like adhesive that have higher heat dissipation properties after curing than before curing.

JP 2008-218571 A Patent No. 6396189

However, conventional dicing and die bonding integrated films do not have sufficient heat dissipation properties, and there is still room for improvement.

Therefore, one aspect of the present disclosure aims to provide an integrated dicing and die bonding film with excellent heat dissipation properties.

The inventors conducted intensive research to solve the above problem and found that when silver-containing particles have an oxide layer (oxide film) on the surface, they tend to have insufficient heat dissipation properties compared to particles that do not have an oxide layer (oxide film). After further research, the inventors found that by incorporating a flux agent into the die bonding film, excellent heat dissipation properties are achieved, leading to the completion of the disclosed invention.

One aspect of the present disclosure relates to a dicing/die bonding integrated film. The dicing/die bonding integrated film contains silver-containing particles having an oxide layer (oxide film) on the surface, and a fluxing agent. The content of the silver-containing particles is 75 mass% or more based on the total amount of the die bonding film. Such a dicing/die bonding integrated film can have excellent heat dissipation properties. The reason why such an effect is achieved is not necessarily clear, but it is thought that, for example, the fluxing agent sufficiently reduces and removes the oxide layer (oxide film) on the metal surface, and that this state is maintained.

The fluxing agent may be an aromatic carboxylic acid. In a dicing/die bonding integrated film having an adhesive layer and a bonding agent layer, if the adhesive strength between the adhesive layer and the bonding agent layer is not sufficiently reduced, a problem may occur in which the chip with the adhesive piece cannot be picked up from the adhesive layer in the subsequent pick-up process. By using an aromatic carboxylic acid as the fluxing agent, it is possible to sufficiently reduce the adhesive strength between the adhesive layer and the bonding agent layer after ultraviolet irradiation.

The die bonding film may further contain a thermosetting resin, a curing agent, and an elastomer. Die bonding films containing these tend to have an easier-to-adjust surface roughness (Ra).

The thermosetting resin may contain an epoxy resin that is liquid at 25°C. When the thermosetting resin contains such an epoxy resin, it tends to be easier to obtain a die bonding film with improved surface roughness (Ra).

Another aspect of the present disclosure relates to a method for manufacturing a semiconductor device. The method for manufacturing a semiconductor device includes a step of attaching the die bonding film of the dicing/die bonding integrated film described above to a semiconductor wafer, a step of singulating the semiconductor wafer and the die bonding film, a step of picking up the semiconductor chip to which the die bonding film piece is attached from the dicing tape, and a step of adhering the semiconductor chip to a support substrate via the die bonding film piece. The method for manufacturing a semiconductor device may further include a step of irradiating the adhesive layer with ultraviolet light after the step of singulating the semiconductor wafer and the die bonding film. According to such a method for manufacturing a semiconductor device, it is possible to manufacture a semiconductor device with excellent heat dissipation properties by using the above-mentioned dicing/die bonding integrated film.

Another aspect of the present disclosure relates to a die bonding film. The die bonding film contains silver-containing particles having an oxide layer on the surface and a fluxing agent. The content of the silver-containing particles is 75 mass% or more based on the total amount of the die bonding film.

According to the present disclosure, a dicing/die bonding integrated film having excellent heat dissipation properties is disclosed. Some embodiments of the dicing/die bonding integrated film are capable of sufficiently reducing the adhesive strength between the adhesive layer and the adhesive layer after ultraviolet light irradiation. In addition, according to the present disclosure, a method for manufacturing a semiconductor device using such a dicing/die bonding integrated film is provided. Furthermore, according to the present disclosure, a die bonding film suitable for use with such a dicing/die bonding integrated film is provided.

FIG. 1 is a schematic cross-sectional view showing one embodiment of a die bonding film. FIG. 2 is a schematic cross-sectional view showing one embodiment of a dicing/die bonding integrated film. 3A, 3B, 3C, 3D, 3E, and 3F are schematic cross-sectional views showing each step of a method for manufacturing a semiconductor device according to an embodiment of the present invention. FIG. 4 is a schematic cross-sectional view showing one embodiment of a semiconductor device.

Below, an embodiment of the present disclosure will be described with reference to the drawings as appropriate. However, the present disclosure is not limited to the following embodiment. In the following embodiment, the components (including steps, etc.) are not essential unless specifically stated. The size of the components in each figure is conceptual, and the relative relationship of the size between the components is not limited to that shown in each figure.

The same applies to the numerical values and their ranges in this specification, and they do not limit this disclosure. In this specification, a numerical range indicated using "~" indicates a range that includes the numerical values before and after "~" as the minimum and maximum values, respectively. In numerical ranges described in stages in this specification, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. In addition, in numerical ranges described in this specification, the upper or lower limit value of the numerical range may be replaced with a value shown in an example.

In this specification, (meth)acrylate means acrylate or the corresponding methacrylate. The same applies to other similar expressions such as (meth)acryloyl group, (meth)acrylic copolymer, etc.

[Die bonding film]
Fig. 1 is a schematic cross-sectional view showing one embodiment of a die bonding film. The die bonding film 10 shown in Fig. 1 has a first surface 10A and a second surface 10B opposite to the first surface 10A. The first surface 10A can be a surface to be placed on an adhesive layer of a dicing tape, as described below. The die bonding film 10 may be provided on a support film 20, as shown in Fig. 1. The die bonding film 10 is thermosetting, and can be in a semi-cured (B stage) state and then in a completely cured (C stage) state after a curing process.

The die bonding film 10 contains (a) silver-containing particles having an oxide layer on the surface and (b) a fluxing agent, and may further contain (c) a thermosetting resin, (d) a curing agent, and (f) an elastomer, as necessary.

Component (a): Silver-containing particles having an oxide layer on the surface Component (a) is a component used to enhance heat dissipation in the die bonding film. The silver-containing particles may be, for example, silver particles made of silver or silver-coated metal particles (such as silver-coated copper particles) in which the surface of metal particles (such as copper particles) is coated with silver. The silver-containing particles may be silver particles made of silver.

Since the silver in the silver-containing particles has a property of being easily oxidized, silver-containing particles that are not surface-treated with a protective material or the like usually tend to have an oxide layer (oxide film) on the surface. The component (a) is not particularly limited as long as it is a silver-containing particle having an oxide layer (oxide film) on the surface, but from the viewpoint of ease of availability, for example, it may be a silver-containing particle manufactured by an atomization method. Here, the atomization method is a method in which a molten metal or alloy is made to flow out from a small hole in the bottom of a crucible to form a thin stream, and high-speed air, nitrogen, argon, water, etc. are sprayed onto it to scatter the molten metal and rapidly cool and solidify it to obtain a powder (particles). The obtained powder is sintered to prevent agglomeration, so that an oxide layer (oxide film) tends to be formed on the surface by oxygen in the air. Examples of such silver-containing particles include Ag-HWQ series (product name, manufactured by Fukuda Metal Foil Powder Co., Ltd.) and conductive atomized powder (product name, manufactured by Dowa Electronics Co., Ltd.).

The average particle size of the (a) component may be 0.01 to 10 μm. When the average particle size of the (a) component is 0.01 μm or more, the viscosity increase when the adhesive varnish is prepared is prevented, the desired amount of the (a) component can be contained in the die bonding film, and the wettability of the die bonding film to the adherend is ensured, and there is a tendency that better adhesion can be exhibited. When the average particle size of the (a) component is 10 μm or less, there is a tendency that the film formability is excellent and the heat dissipation due to the addition of the (a) component can be further improved. In addition, by setting it in such a range, the thickness of the die bonding film can be made thinner, and the semiconductor chip can be highly laminated, and the occurrence of chip cracks due to the protrusion of conductive particles from the die bonding film tends to be prevented. The average particle size of the (a) component may be 0.1 μm or more, 0.5 μm or more, 1.0 μm or more, or 1.5 μm or more, and may be 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 the (a) component is 5.0 μm or less, a die bonding film with improved surface roughness (Ra) tends to be obtained. The average particle size of the (a) component means the particle size (D _{50 ) when the ratio (volume fraction) to the total volume of the (a) component is 50%. The average particle size (D 50 )} of the (a) component can be determined by measuring a suspension in which the (a) component is suspended in water by a laser scattering method using a laser scattering type particle size measuring device (e.g., Microtrack).

It is preferable that component (a) be spherical particles with an average particle size of 5.0 μm or less.

The content of the (a) component is 75% by mass or more based on the total amount of the die bonding film. When the content of the (a) component is 75% by mass or more based on the total amount of the die bonding film, the thermal conductivity of the die bonding film can be improved, and as a result, the heat dissipation properties can be improved. The content of the (a) component may be 77% by mass or more, 80% by mass or more, 83% by mass or more, or 85% by mass or more based on the total amount of the die bonding film. The upper limit of the content of the (a) component is not particularly limited, but may be 98% by mass or less, 96% by mass or less, or 95% by mass or less based on the total amount of the die bonding film.

(b) Fluxing Agent The (b) component is a component for reducing and removing the oxide layer (oxide film) in the (a) component. The (b) component may be, for example, a compound having a carboxy group (carboxylic acid). Examples of such (b) components include aliphatic carboxylic acids and aromatic carboxylic acids. These may be used alone or in combination of two or more. The (b) component may be solid at 25°C.

Examples of aliphatic carboxylic acids include succinic acid (melting point: 184°C), glutaric acid (melting point: 95-98°C), adipic acid (melting point: 152°C), pimelic acid (melting point: 103-105°C), suberic acid (melting point: 141-144°C), azelaic acid (melting point: 109°C), sebacic acid (melting point: 133-137°C), undecanedioic acid (melting point: 28-31°C), and dodecanedioic acid (melting point: 127-129°C). The aliphatic carboxylic acid may be, for example, glutaric acid.

Examples of aromatic carboxylic acids include diphenylacetic acid (melting point: 147-149°C), benzilic acid (melting point: 150-152°C), 4,4-bis(4-hydroxyphenyl)valeric acid (melting point: 147-177°C), 2,5-dihydroxybenzoic acid (melting point: 200-205°C), 3,4,5-trihydroxybenzoic acid (melting point: 250°C), 1,2,4-benzenetricarboxylic acid (melting point: 231°C), 1,3,5-benzenetricarboxylic acid (melting point: >300°C), and 2-[bis(4-hydroxyphenyl)methyl]benzoic acid (melting point: 126°C). The aromatic carboxylic acid may be, for example, benzilic acid.

From the viewpoint of sufficiently reducing the adhesive strength between the pressure-sensitive adhesive layer and the adhesive layer after ultraviolet irradiation, the component (b) may be a compound having a carboxy group (carboxylic acid) that satisfies one or more of the following conditions:
Component (b) is an aromatic carboxylic acid.
The melting point of component (b) is 100°C or higher, preferably 120°C or higher, and more preferably 140°C or higher; and is 200°C or lower, preferably 180°C or lower, and more preferably 160°C or lower.
Component (b) is a carboxylic acid having a hydroxyl group.

Component (b) may be, for example, glutaric acid or benzilic acid, or may be benzilic acid.

The content of the (b) component may be 0.1 to 15% by mass based on the total amount of the die bonding film. When the content of the (b) component is 0.1% by mass or more based on the total amount of the die bonding film, the oxide layer in the (a) component can be sufficiently reduced and removed, and heat dissipation tends to be improved. When the content of the (b) component is 15% by mass or less based on the total amount of the die bonding film, the amount of other components (particularly the (c), (d), and (e) components) can be sufficiently secured, the adherend of the die bonding film can be secured, and the film formability tends to be excellent. The content of the (b) component may be 0.2% by mass or more, 0.5% by mass or more, 0.8% by mass or more, 1% by mass or more, 1.2% by mass or more, or 1.5% by mass or more based on the total amount of the die bonding film, and may be 12% by mass or less, 10% by mass or less, 8% by mass or less, or 6% by mass or less.

Component (c): Thermosetting resin Component (c) is a component that has the property of forming a three-dimensional bond between molecules and curing by heating or the like, and is a component that exhibits adhesive properties after curing. Component (c) may be an epoxy resin. Component (c) may contain an epoxy resin that is liquid at 25°C. The epoxy resin may be any epoxy resin that has an epoxy group in the molecule. The epoxy resin may have two or more epoxy groups in the molecule.

Examples of epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, bisphenol A novolac type epoxy resins, bisphenol F novolac type epoxy resins, stilbene type epoxy resins, triazine skeleton-containing epoxy resins, fluorene skeleton-containing epoxy resins, triphenol methane type epoxy resins, biphenyl type epoxy resins, xylylene type epoxy resins, biphenyl aralkyl type epoxy resins, naphthalene type epoxy resins, dicyclopentadiene type epoxy resins, polyfunctional phenols, diglycidyl ether compounds of polycyclic aromatics such as anthracene, etc. These may be used alone or in combination of two or more. Among these, the epoxy resin may be a bisphenol type epoxy resin or a cresol novolac type epoxy resin from the viewpoint of heat resistance of the cured product, etc.

The epoxy resin may contain an epoxy resin that is liquid at 25°C. By containing such an epoxy resin, it tends to be easier to obtain a die bonding film with improved surface roughness (Ra). Examples of commercially available epoxy resins that are liquid at 25°C include EXA-830CRP (product name, manufactured by DIC Corporation) and YDF-8170C (product name, manufactured by Nippon Steel Chemical & Material Co., Ltd.).

The epoxy equivalent of the epoxy resin is not particularly limited, but may be 90 to 300 g/eq, 110 to 290 g/eq, or 110 to 290 g/eq. When the epoxy equivalent of component (A) is within such a range, it tends to be easier to ensure the fluidity of the adhesive composition when forming the die bonding film while maintaining the bulk strength of the die bonding film.

The content of component (c) may be 0.1 mass% or more, 0.5 mass% or more, 1 mass% or more, or 1.5 mass% or more, based on the total amount of the die bonding film, and may be 15 mass% or less, 12 mass% or less, 10 mass% or less, 8 mass% or less, or 6 mass% or less.

When the (c) component contains an epoxy resin that is liquid at 25°C, the mass ratio of the epoxy resin to the (c) component (mass of the epoxy resin/total mass of the (c) component) may be, in percentage, 10 to 100%, 40 to 100%, 60% to 100%, or 80% to 100%. When the (c) component contains an epoxy resin that is liquid at 25°C, the content of the epoxy resin may be 0.1 mass% or more, 0.5 mass% or more, 1 mass% or more, or 1.5 mass% or more, and may be 15 mass% or less, 12 mass% or less, 10 mass% or less, 8 mass% or less, or 6 mass% or less, based on the total amount of the die bonding film.

Component (d): Curing Agent Component (d) may be a phenolic resin that can be a curing agent for epoxy resins. Any phenolic resin can be used without particular limitation as long as it has a phenolic hydroxyl group in the molecule. Examples of phenolic resins include novolak-type phenolic resins obtained by condensing or co-condensing phenols such as phenol, cresol, resorcin, catechol, bisphenol A, bisphenol F, phenylphenol, aminophenol, etc. and/or naphthols such as α-naphthol, β-naphthol, dihydroxynaphthalene, etc. with a compound having an aldehyde group such as formaldehyde under an acidic catalyst, allylated bisphenol A, allylated bisphenol F, allylated naphthalenediol, phenol novolak, phenol aralkyl resins synthesized from phenols such as phenol and/or naphthols and dimethoxyparaxylene or bis(methoxymethyl)biphenyl, naphthol aralkyl resins, biphenyl aralkyl-type phenolic resins, phenyl aralkyl-type phenolic resins, etc. These may be used alone or in combination of two or more.

The hydroxyl equivalent of the phenolic resin may be 40 to 300 g/eq, 70 to 290 g/eq, or 100 to 280 g/eq. If the hydroxyl equivalent of the phenolic resin is 40 g/eq or more, the storage modulus of the film tends to be improved, and if it is 300 g/eq or less, it is possible to prevent defects due to the generation of foaming, outgassing, etc.

From the viewpoint of curability, the ratio of the epoxy equivalent of the epoxy resin (c) to the hydroxyl equivalent of the phenolic resin (d) (epoxy equivalent of the epoxy resin (c)/hydroxyl equivalent of the phenolic resin (d)) may 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. If the equivalent ratio is 0.30/0.70 or more, more sufficient curability tends to be obtained. If the equivalent ratio is 0.70/0.30 or less, it is possible to prevent the viscosity from becoming too high, and more sufficient fluidity can be obtained.

The content of component (d) may be 0.1 mass% or more, 0.3 mass% or more, 0.5 mass% or more, or 1 mass% or more based on the total amount of the die bonding film, and may be 12 mass% or less, 10 mass% or less, 8 mass% or less, 6 mass% or less, or 4 mass% or less.

Component (e): Elastomer Examples of the component (e) include polyimide resin, acrylic resin, urethane resin, polyphenylene ether resin, polyetherimide resin, phenoxy resin, modified polyphenylene ether resin, etc. Component (e) may be any of these resins having a crosslinkable functional group, or may be an acrylic resin having a crosslinkable functional group. Here, the acrylic resin means a polymer containing a structural unit derived from a (meth)acrylic acid ester. The acrylic resin may be a polymer containing a structural unit derived from a (meth)acrylic acid ester having a crosslinkable functional group such as an epoxy group, an alcoholic or phenolic hydroxyl group, or a carboxy group as a structural unit. The acrylic resin may also be an acrylic rubber such as a copolymer of a (meth)acrylic acid ester and an acrylonitrile. These may be used alone or in combination of two or more.

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

The glass transition temperature (Tg) of component (e) may be -50 to 50°C or -30 to 20°C. When the Tg of the acrylic resin is -50°C or higher, the tackiness of the die bonding film tends to be reduced, leading to improved handleability. When the Tg of the acrylic resin is 50°C or lower, the fluidity of the adhesive composition when forming the die bonding film tends to be more sufficiently ensured. Here, the glass transition temperature (Tg) of component (e) refers to the value measured using a DSC (differential scanning calorimeter) (for example, Thermo Plus 2, product name, manufactured by Rigaku Corporation).

The weight average molecular weight (Mw) of component (e) may 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 (e) is 50,000 or more, the film-forming property tends to be better. When the weight average molecular weight of component (e) is 1.6 million or less, the adhesive composition tends to have better fluidity when forming a die bonding film. The weight average molecular weight (Mw) is a value measured by gel permeation chromatography (GPC) and converted using a calibration curve based on standard polystyrene.

The measurement device, measurement conditions, etc. for the weight average molecular weight (Mw) of the component (e) are, for example, as follows:
Pump: L-6000 (manufactured by Hitachi, Ltd.)
Column: A column in which 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 10.7 mm (diameter) × 300 mm) are connected in this order. Eluent: Tetrahydrofuran (hereinafter referred to as "THF")
Sample: 120 mg of sample dissolved in 5 mL of THF Flow rate: 1.75 mL/min

The content of component (e) may be 0.1 mass% or more, 0.3 mass% or more, 0.5 mass% or more, or 0.8 mass% or more, based on the total amount of the die bonding film, and may be 10 mass% or less, 8 mass% or less, 5 mass% or less, or 3 mass% or less.

The die bonding film 10 may further contain (f) a curing accelerator.

(f) component: curing accelerator The die bonding film tends to have both adhesiveness and connection reliability by containing the (f) component. Examples of the (f) component include imidazoles and their derivatives, organic phosphorus compounds, secondary amines, tertiary amines, and quaternary ammonium salts. These may be used alone or in combination of two or more. Among these, the (f) component may be imidazoles and their derivatives from the viewpoint of reactivity.

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

The content of component (f) may be 0.001 to 1 mass % based on the total amount of the die bonding film. When the content of component (f) is within this range, it tends to be possible to achieve a better balance between adhesion and connection reliability.

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

The die bonding film 10 shown in FIG. 1 can be produced by forming an adhesive composition containing the above-mentioned components (a) and (b), and, if necessary, components (c) to (f) and other components, into a film. Such a die bonding film 10 can be formed by applying the adhesive composition to a support film 20. The adhesive composition can be used as an adhesive varnish diluted with a solvent. When an adhesive varnish is used, the adhesive varnish is applied to the support film 20, and the solvent is removed by heating and drying, thereby forming the die bonding film 10.

The solvent is not particularly limited as long as it can dissolve components other than component (a). Examples of the solvent include aromatic hydrocarbons such as toluene, xylene, mesitylene, cumene, and p-cymene; 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 may be used alone or in combination of two or more. Among these, the solvent may be toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, or cyclohexanone from the viewpoints of solubility and boiling point. The solid component concentration in the adhesive varnish may be 10 to 80% by mass based on the total mass of the adhesive varnish.

The adhesive varnish can be prepared by mixing and kneading components (a) to (f), other components, and a solvent. The order of mixing and kneading the components is not particularly limited and can be set as appropriate. Mixing and kneading can be performed using an appropriate combination of dispersing machines such as a normal mixer, a grinding machine, a triple roll, a ball mill, or a bead mill. After preparing the adhesive varnish, air bubbles in the varnish can be removed by vacuum degassing or the like.

The support film 20 is not particularly limited, and examples thereof include films of polytetrafluoroethylene, polyethylene, polypropylene, polymethylpentene, polyethylene terephthalate, polyimide, and the like. The support film may be subjected to a release treatment. The thickness of the support film 20 may be, for example, 10 to 200 μm or 20 to 170 μm.

The adhesive varnish can be applied to the support film 20 by any known method, such as knife coating, roll coating, spray coating, gravure coating, bar coating, curtain coating, etc. The conditions for heat drying are not particularly limited as long as the solvent used is sufficiently volatilized, but may be, for example, 50 to 200°C for 0.1 to 90 minutes.

The thickness of the die bonding film 10 can be adjusted appropriately depending on the application, but may be, for example, 3 to 200 μm. If the thickness of the die bonding film 10 is 3 μm or more, the adhesive strength with the semiconductor wafer tends to be sufficient, and if it is 200 μm or less, the heat dissipation tends to be sufficient. From the viewpoint of adhesive strength and thinning of the semiconductor device, the thickness of the die bonding film 10 may be 5 to 100 μm or 10 to 50 μm.

In the die bonding film 10, the surface roughness of the first surface 10A may be, for example, 1.0 μm or less. Here, the first surface 10A is the surface placed on the adhesive layer of the dicing tape (i.e., the surface opposite to the surface in contact with the support film 20 of the die bonding film 10). In this specification, the surface roughness means the arithmetic mean roughness Ra (JIS B 0601-2001), and the arithmetic mean roughness Ra means a value calculated by the method described in the examples. The measurement magnification may be 50 to 100 times.

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 adhesion due to the surface roughness. 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, from the viewpoint of preventing a decrease in the anchor effect due to the surface becoming too smooth.

The die bonding film of the present disclosure is believed to have excellent heat dissipation properties because the (b) component sufficiently reduces and removes the oxide layer (oxide film) on the surface of the (a) component, and this state is further maintained. Therefore, the die bonding film of the present disclosure can be suitably used as a dicing/die bonding integrated film in combination with a dicing tape having an adhesive layer.

[Dicing and die bonding integrated film]
Fig. 2 is a schematic cross-sectional view showing one embodiment of a dicing/die bonding integrated film. The dicing/die bonding integrated film 100 shown in Fig. 2 includes a dicing tape 50 having a substrate 40 and an adhesive layer 30 provided on the substrate 40, and a die bonding film 10 arranged on the adhesive layer 30 of the dicing tape 50. The die bonding film 10 has a first surface 10A and a second surface 10B opposite to the first surface 10A. The dicing/die bonding integrated film 100 may include a support film 20 on the second surface 10B of the die bonding film 10.

The substrate 40 in the dicing tape 50 may be, for example, a plastic film such as a polytetrafluoroethylene film, a polyethylene terephthalate film, a polyethylene film, a polypropylene film, a polymethylpentene film, or a polyimide film. In addition, the substrate 40 may be subjected to a surface treatment such as a primer coating, a UV treatment, a corona discharge treatment, a polishing treatment, or an etching treatment, as necessary.

The adhesive layer 30 may be an adhesive layer made of an adhesive used in the field of dicing tape, and may be an adhesive layer made of a pressure-sensitive adhesive or an adhesive layer made of an ultraviolet-curing adhesive. When the adhesive layer 30 is an adhesive layer made of an ultraviolet-curing adhesive, the adhesive layer 30 may have the property of decreasing its adhesiveness when irradiated with ultraviolet light.

The integrated dicing and die bonding film 100 can be produced by preparing a dicing tape 50 and a die bonding film 10, and attaching the first surface 10A of the die bonding film 10 to the adhesive layer 30 of the dicing tape 50.

In the dicing/die bonding integrated film 100, the die bonding film 10 contains 75% by mass or more of the component (a) based on the total amount of the die bonding film. A dicing/die bonding integrated film having such an adhesive layer and adhesive layer can have excellent heat dissipation properties.

[Method of manufacturing semiconductor device (semiconductor package)]
3A, 3B, 3C, 3D, 3E, and 3F are schematic cross-sectional views showing each step of a method for manufacturing a semiconductor device according to an embodiment of the present invention. The method for manufacturing a semiconductor device includes a step of attaching the die bonding film 10 (adhesive layer) (the second surface 10B) of the dicing/die bonding integrated film 100 to a semiconductor wafer W (wafer lamination step, see FIGS. 3(a) and 3(b)), a step of dividing the semiconductor wafer W and the die bonding film 10 (adhesive layer) (dicing step, see FIG. 3(c)), a step of irradiating the adhesive layer 30 (through the substrate 40) with ultraviolet light as necessary (ultraviolet light irradiation step, see FIG. 3(d)), a step of picking up the semiconductor chip Wa (semiconductor chip 60 with adhesive piece) to which the die bonding film piece 10a is attached from the adhesive layer 30a (pickup step, see FIG. 3(e)), and a step of adhering the semiconductor chip 60 with adhesive piece to a support substrate 80 through the die bonding film piece 10a (semiconductor chip adhering step, see FIG. 3(f)).

<Wafer lamination process>
First, the dicing and die bonding integrated film 100 is placed in a predetermined device. Then, the second surface 10B of the die bonding film 10 (adhesive layer) of the dicing and die bonding integrated film 100 is attached to the surface Ws of the semiconductor wafer W (see FIGS. 3(a) and 3(b)). It is preferable that the circuit surface of the semiconductor wafer W is provided on the surface opposite to the surface Ws.

<Dicing process>
Next, the semiconductor wafer W and the die bonding film 10 (adhesive layer) are diced (see FIG. 3(c)). At this time, a part of the adhesive layer 30, or the entire adhesive layer 30 and a part of the base material 40 may be diced. In this manner, the dicing and die bonding integrated film 100 also functions as a dicing sheet.

<Ultraviolet ray irradiation process>
Next, as necessary, the adhesive layer 30 is irradiated with ultraviolet light (through the substrate 40) (see FIG. 3(d)). This causes the adhesive layer 30 to harden, and the adhesive strength between the adhesive layer 30 and the die bonding film 10 (adhesive layer) can be sufficiently reduced. For ultraviolet light irradiation, it is preferable to use ultraviolet light with a wavelength of 200 to 400 nm. The ultraviolet light irradiation conditions are preferably adjusted so that the illuminance and the dose are in the ranges of 30 to 240 mW/ ^cm2 and 50 to 500 mJ/ ^cm2 , respectively.

<Pickup process>
Next, the diced semiconductor chips 60 with adhesive pieces are separated from each other by expanding the substrate 40, and the semiconductor chips 60 with adhesive pieces pushed up by the needles 72 from the substrate 40 side are sucked by the suction collet 74 to be picked up from the adhesive layer 30a (see FIG. 3(e)). The semiconductor chips 60 with adhesive pieces have a semiconductor chip Wa and a die bonding film piece 10a. The semiconductor chip Wa is a semiconductor wafer W that has been diced into individual pieces, and the die bonding film piece 10a is a die bonding film 10 that has been diced into individual pieces. The adhesive layer 30a is a layer that has been diced into individual pieces. The adhesive layer 30a may remain on the substrate 40 when the semiconductor chips 60 with adhesive pieces are picked up. In the pick-up process, it is not necessarily necessary to expand the substrate 40, but by expanding the substrate 40, the pick-up property can be further improved.

The amount of pushing up by the needle 72 can be set as appropriate. Furthermore, from the viewpoint of ensuring sufficient pick-up capability even for extremely thin wafers, for example, two or three stages of pushing up may be performed. Also, the semiconductor chip 60 with adhesive piece attached may be picked up by a method other than the method using the suction collet 74.

<Semiconductor chip bonding process>
After picking up the semiconductor chip 60 with the adhesive piece, the semiconductor chip 60 with the adhesive piece is bonded to the support substrate 80 via the die bonding film piece 10a by thermocompression bonding (see FIG. 3(f)). A plurality of semiconductor chips 60 with adhesive pieces may be bonded to the support substrate 80.

The method for manufacturing a semiconductor device may further include, as necessary, a step of electrically connecting the semiconductor chip Wa and the support substrate 80 by wire bonding, and a step of resin-encapsulating the semiconductor chip Wa on the surface 80A of the support substrate 80 using a resin encapsulant.

Figure 4 is a schematic cross-sectional view showing one embodiment of a semiconductor device. The semiconductor device 200 shown in Figure 4 can be manufactured through the above-mentioned process. In the semiconductor device 200, the semiconductor chip Wa and the support substrate 80 may be electrically connected by wire bonds 70. In the semiconductor device 200, the semiconductor chip Wa may be resin-encapsulated on the surface 80A of the support substrate 80 using a resin encapsulant 92. Solder balls 94 may be formed on the surface of the support substrate 80 opposite the surface 80A for electrical connection with an external substrate (motherboard).

The present disclosure will be explained below using examples, but the present disclosure is not limited to these examples.

<Preparation of adhesive varnish>
Cyclohexanone was added to (c) epoxy resin as a thermosetting resin, (d) phenolic resin as a curing agent, and (e) acrylic rubber as an elastomer, with the symbols and composition ratios (unit: parts by mass) shown in Table 1, and the mixture was stirred to obtain a mixture. After each component was dissolved, (a) silver-containing particles having an oxide layer on the surface were added to the mixture, and the mixture was stirred using a dispersing blade to disperse each component until it was uniform. Thereafter, (f) a curing accelerator was added, and each component was dispersed until it was uniform, to obtain adhesive varnishes A to G with a solid content of 78% by mass.

The symbols for each component in Table 1 refer to the following products.

(a) Silver-containing particles having an oxide layer on the surface: Ag-HWQ 1.5 μm (product name, silver particles produced by atomization method, manufactured by Fukuda Metal Foil and Powder Co., Ltd., shape: spherical, average particle size (laser 50% particle size (D ₅₀ )): 1.0 to 2.0 μm)

(b) Fluxing agent: glutaric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., molecular weight: 132.1)
Benzilic acid (manufactured by Tokyo Chemical Industry Co., Ltd., aromatic carboxylic acid, molecular weight: 228.3)

(c) Thermosetting resin: EXA-830CRP (product name, manufactured by DIC Corporation, bisphenol type epoxy resin, epoxy equivalent: 159 g/eq, liquid at 25° C.)

(d) Hardener: MEH-7800M (product name, manufactured by Meiwa Kasei Co., Ltd., phenolic resin, viscosity (150°C): 0.31 to 0.43 Pa·s (3.1 to 4.3 poise), hydroxyl equivalent: 175 g/eq)

(e) Elastomer HTR-860P-3CSP (product name, manufactured by Nagase ChemteX Corporation, acrylic rubber, weight average molecular weight: 1 million, Tg: -7°C)
SG-280 EK23 (product name, Nagase ChemteX Corporation, acrylic rubber, weight average molecular weight: 900,000, Tg: -29°C)

(f) Curing accelerator: 2PZ-CN (trade name, manufactured by Shikoku Chemical Industry Co., Ltd., 1-cyanoethyl-2-phenylimidazole)

Example 1
<Preparation of die bonding film>
Adhesive varnish A was used to prepare the die bonding film. The adhesive varnish A, which had been vacuum degassed, was applied to a polyethylene terephthalate (PET) film (thickness 38 μm) that had been subjected to a release treatment, which was a support film. The applied varnish was heated and dried in two stages, at 90° C. for 5 minutes and then at 130° C. for 5 minutes, to prepare a die bonding film of Example 1 having a thickness of 20 μm in a B-stage state on the support film.

<Measurement of thermal conductivity>
(Preparation of film for measuring thermal conductivity)
A laminated film having a thickness of 100 μm or more was prepared by laminating a plurality of the die bonding films of Example 1 with a rubber roll. The laminated film obtained was covered on both sides with PET films and thermally cured at 110° C. for 1 hour and then at 170° C. for 3 hours to obtain a film for measuring thermal conductivity.

(Measurement of thermal conductivity)
The thermal conductivity of the film for measuring thermal conductivity was calculated by the following formula. The results are shown in Table 2.
Thermal conductivity (W/m・K) = Thermal diffusivity α (mm ² /s) × Specific heat Cp (J/g・K) × Specific gravity (g/cm ³ )
The thermal diffusivity α, the specific heat Cp, and the specific gravity were measured by the following methods. A higher thermal conductivity means better heat dissipation properties.

(Measurement of thermal diffusivity α)
The thermal conductivity measurement film obtained above was cut into 10 mm squares. Blackguard spray (FC-153, manufactured by Fine Chemical Japan Co., Ltd.) was applied to both sides of the cut thermal conductivity measurement film to prepare a measurement sample. For the measurement, a flash analyzer (LFA467 HyperFlash, manufactured by Netsch Japan Co., Ltd.) was used to measure the thermal diffusivity α at 35°C.

(Measurement of specific heat Cp)
The specific heat Cp at 35° C. was calculated by measuring using a differential scanning calorimeter (DSC) (high sensitivity differential scanning calorimeter DSC8231 (manufactured by Rigaku Corporation)) at a temperature rise rate of 10° C./min and at temperatures of 25° C. to 70° C.

(Measurement of specific gravity)
The measurement was performed by the Archimedes method using an electronic specific gravity meter (EW-300SG, manufactured by Alpha Mirage Co., Ltd.).

<Production of integrated dicing and die bonding tape>
A dicing tape having a substrate and an adhesive layer (product name: 6363-30, manufactured by Hitachi Chemical Co., Ltd.) was prepared, and the adhesive layer of the dicing tape was bonded to the die bonding film of Example 1 with a rubber roll to produce an integrated dicing and die bonding tape of Example 1 having a substrate, an adhesive layer, and an adhesive layer (die bonding film) in that order.

<Measurement of T-peel strength between adhesive layer and adhesive layer before and after UV irradiation>
The dicing and die bonding integrated tape of Example 1 was prepared, and the T-peel strength between the adhesive layer and the adhesive layer was measured using this. An autograph EZ-S 50N (manufactured by Shimadzu Corporation) was used for the measurement. An easy-cut tape (manufactured by Oji Tack Co., Ltd.) was attached to the adhesive layer (die bonding film) side of the dicing and die bonding integrated tape, and the dicing and die bonding integrated tape was cut into a size of 25 mm wide and 100 mm long to obtain a sample. Using this sample, the T-peel strength between the adhesive layer and the adhesive layer before and after ultraviolet irradiation was measured at a chuck distance of 50 mm and a speed of 300 mm/min. The ultraviolet irradiation was performed with a halogen lamp under conditions of 80 mW/cm ² and 200 mJ/cm ^2. The measurement was performed three times each before and after ultraviolet irradiation, and the average value of the three times was taken as the peel strength. The results are shown in Table 2.

Example 2
Except for using adhesive varnish B to prepare the die bonding film, the die bonding film and the dicing/die bonding integrated tape of Example 2 were obtained in the same manner as in Example 1. The thermal conductivity and the T-peel strength between the adhesive layer and the adhesive layer before and after ultraviolet irradiation were measured for the die bonding film and the dicing/die bonding integrated tape of Example 2 in the same manner as in Example 1. The results are shown in Table 2.

Example 3
Except for using adhesive varnish C to prepare the die bonding film, the die bonding film and the dicing/die bonding integrated tape of Example 3 were obtained in the same manner as in Example 1. The thermal conductivity and the T-peel strength between the adhesive layer and the adhesive layer before and after ultraviolet irradiation were measured for the die bonding film and the dicing/die bonding integrated tape of Example 3 in the same manner as in Example 1. The results are shown in Table 2.

Example 4
Except for using adhesive varnish D to prepare the die bonding film, the die bonding film and the dicing/die bonding integrated tape of Example 4 were obtained in the same manner as in Example 1. The thermal conductivity and the T-peel strength between the adhesive layer and the adhesive layer before and after ultraviolet irradiation were measured for the die bonding film and the dicing/die bonding integrated tape of Example 4 in the same manner as in Example 1. The results are shown in Table 2.

Example 5
Except for using adhesive varnish E to prepare the die bonding film, the die bonding film and the dicing/die bonding integrated tape of Example 5 were obtained in the same manner as in Example 1. The thermal conductivity and the T-peel strength between the adhesive layer and the adhesive layer before and after ultraviolet irradiation were measured for the die bonding film and the dicing/die bonding integrated tape of Example 5 in the same manner as in Example 1. The results are shown in Table 2.

Example 6
Except for using adhesive varnish F to prepare the die bonding film, the die bonding film and the dicing/die bonding integrated tape of Example 6 were obtained in the same manner as in Example 1. The thermal conductivity and the T-peel strength between the adhesive layer and the adhesive layer before and after ultraviolet irradiation were measured for the die bonding film and the dicing/die bonding integrated tape of Example 6 in the same manner as in Example 1. The results are shown in Table 2.

(Comparative Example 1)
A die bonding film and a dicing/die bonding integrated tape of Comparative Example 1 were obtained in the same manner as in Example 1, except that adhesive varnish G was used to prepare the die bonding film. The thermal conductivity of the die bonding film of Comparative Example 1 was measured in the same manner as in Example 1. The results are shown in Table 2. Note that, since the thermal conductivity of the die bonding film of Comparative Example 1 was insufficient, the T-peel strength between the adhesive layer and the adhesive layer of the dicing/die bonding integrated tape of Comparative Example 1 was not measured before and after ultraviolet irradiation. The results are shown in Table 2.

As shown in Table 2, the integrated dicing and die bonding tapes of Examples 1 to 6, which contain a flux agent, had superior thermal conductivity compared to the integrated dicing and die bonding tape of Comparative Example 1, which does not contain a flux agent. In addition, it was found that the integrated dicing and die bonding tapes of Examples 5 and 6, which contain benzilic acid, can reduce the T-peel strength after ultraviolet irradiation compared to the T-peel strength before ultraviolet irradiation. These results confirmed that the integrated dicing and die bonding film of the present disclosure has excellent heat dissipation properties.

10...Die bonding film, 10A...First surface, 10B...Second surface, 10a...Die bonding film piece, 20...Support film, 30...Adhesive layer, 40...Substrate, 50...Dicing tape, 60...Semiconductor chip with adhesive piece, 70...Wire bond, 72...Needle, 74...Suction collet, 80...Support substrate, 92...Resin encapsulant, 94...Solder ball, 100...Dicing and die bonding integrated film, 200...Semiconductor device.

Claims (10)

a dicing tape having a substrate and an adhesive layer provided on the substrate;
a die bonding film disposed on the adhesive layer of the dicing tape;
Equipped with
The die bonding film contains silver-containing particles having an oxide layer on a surface thereof, a fluxing agent , a thermosetting resin, and an elastomer ;
The content of the silver-containing particles is 75 mass% or more based on the total amount of the die bonding film.
Integrated dicing and die bonding film. The fluxing agent is an aromatic carboxylic acid.
2. The dicing and die bonding integrated film according to claim 1. The die bonding film further contains a curing agent .
3. The dicing and die bonding integrated film according to claim 1 or 2. The thermosetting resin contains an epoxy resin that is liquid at 25°C.
The dicing and die bonding integrated film according to claim 3 . A step of attaching the die bonding film of the dicing and die bonding integrated film according to any one of claims 1 to 4 to a semiconductor wafer;
singulating the semiconductor wafer and the die bonding film;
picking up the semiconductor chip having the die bonding film piece attached thereto from the dicing tape;
bonding the semiconductor chip to a support substrate via the die bonding film piece;
Equipped with
A method for manufacturing a semiconductor device. The method further includes a step of irradiating the adhesive layer with ultraviolet light after the step of singulating the semiconductor wafer and the die bonding film.
The method for manufacturing a semiconductor device according to claim 5 . The present invention comprises silver-containing particles having an oxide layer on the surface thereof, a fluxing agent , a thermosetting resin, and an elastomer ,
The content of the silver-containing particles is 75 mass% or more based on the total amount of the die bonding film.
Die bonding film. The fluxing agent is an aromatic carboxylic acid.
The die bonding film according to claim 7 . Further containing a curing agent ,
The die bonding film according to claim 7 or 8. The thermosetting resin contains an epoxy resin that is liquid at 25°C.
The die bonding film according to claim 9 .

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