Film-like adhesive, adhesive sheet, semiconductor device, and method for manufacturing the same

Abstract

To provide a filmy adhesive exhibiting superior separability by cooling expansion.SOLUTION: Disclosed is a filmy adhesive for bonding a semiconductor element to a support member for mounting the semiconductor element thereon. The filmy adhesive contains a thermosetting resin, a hardener, and an elastomer. The elastomer satisfies the following requirements (i) and (ii). Requirement (i): a glass transition temperature is 12°C or higher. Requirement (ii): a weight-average molecular weight is 800,000 or lower.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a film-like adhesive, an adhesive sheet, and a semiconductor device and a method for manufacturing the same. [Background technology]

[0002] In recent years, stacked MCPs (Multi-Chip Packages), which consist of multiple layers of semiconductor elements (semiconductor chips), have become widespread and are being used as memory semiconductor packages for mobile phones and portable audio devices. Furthermore, with the increasing functionality of mobile phones and other devices, there is a growing demand for higher speed, higher density, and higher integration in semiconductor packages.

[0003] Currently, a common method for manufacturing semiconductor devices is the semiconductor wafer back-side bonding method, in which a film-like adhesive and dicing tape are attached to the back surface of a semiconductor wafer, and then the semiconductor wafer, film-like adhesive, and a portion of the dicing tape are cut during the dicing process. In this method, it is necessary to cut the film-like adhesive at the same time as dicing the semiconductor wafer. However, in general dicing methods using diamond blades, the cutting speed must be slowed because the semiconductor wafer and film-like adhesive are cut simultaneously, which may lead to increased costs.

[0004] On the other hand, as a method for dividing semiconductor wafers, a method has recently been proposed in which a process is performed to easily divide the semiconductor wafer, such as irradiating the inside of the semiconductor wafer on the cutting line with laser light to form a modified region, and then the semiconductor wafer is cut by expanding the outer periphery (for example, Patent Document 1). This method is called stealth dicing. Stealth dicing is particularly effective in reducing defects such as chipping when the semiconductor wafer is thin, and can be expected to improve yield. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2002-192370 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, because film-type adhesives are flexible and easily stretched, they tend not to break apart easily when dicing tape is expanded. To improve the breakability of film-type adhesives when expanded (especially when cold-expanded at low temperatures (e.g., in the range of -15°C to 0°C)), it is necessary to increase the amount of expansion of the dicing tape. However, increasing the amount of expansion also increases the amount of deflection of the dicing tape, which may adversely affect subsequent conveying processes.

[0007] This invention has been made in view of the above circumstances, and its main objective is to provide a film-like adhesive that exhibits excellent breakability by cooling and expanding. [Means for solving the problem]

[0008] One aspect of the present invention is to provide a film-like adhesive for bonding a semiconductor element to a support member on which the semiconductor element is mounted. The film-like adhesive contains a thermosetting resin, a curing agent, and an elastomer. The elastomer includes an elastomer that satisfies the following conditions (i) and (ii). Such a film-like adhesive may exhibit excellent detachability by cooling expansion. Condition (i): The glass transition temperature is 12°C or higher. Condition (ii): The weight-average molecular weight is 800,000 or less.

[0009] Our inventors have found that using a specific elastomer in a film-like adhesive tends to suppress its flexibility. Therefore, we believe that by using such a specific elastomer, it is possible to suppress excessive increases in the flexibility of the film-like adhesive and, as a result, improve the cleavage of the film-like adhesive in a cooled expanded film.

[0010] The film-like adhesive is derived from the film-like adhesive, with a cross-sectional area A (mm²). 2 The process involves preparing a sample of ), determining the work of cutting W (N·mm), cutting strength P (N), and cutting elongation L (mm) of the sample by a cutting test under low temperature conditions in the range of -15℃ to 0℃, determining the cutting coefficient m represented by the following formula (1), and determining the cutting resistance R (N / mm) represented by the following formula (2). 2 A method for evaluating cleavage properties, which includes a step of determining the cleavage coefficient m and is performed under the following conditions, wherein the cleavage coefficient m is greater than 0 and 70 or less, and the cleavage resistance R is 0 N / mm 2 Super 40N / mm 2 The following may be a film-type adhesive. m = W / [1000 × (P × L)] (1) R = P / A (2) <Condition> Sample width: 5 mm Sample length: 23 mm Relative speed between the pressing jig and the sample: 10 mm / min

[0011] The film-like adhesive may further contain an inorganic filler.

[0012] Another aspect of the present invention is to provide an adhesive sheet comprising a substrate and the above-mentioned film-like adhesive provided on one surface of the substrate.

[0013] Another aspect of the present invention provides a semiconductor device comprising a semiconductor element, a support member on which the semiconductor element is mounted, and an adhesive member provided between the semiconductor element and the support member for bonding the semiconductor element and the support member, wherein the adhesive member is a cured product of the above-mentioned film-like adhesive.

[0014] Another aspect of the present invention provides a method for manufacturing a semiconductor device, comprising a step of bonding a semiconductor element and a support member using the above film-shaped adhesive.

[0015] Another aspect of the present invention provides a method for manufacturing a semiconductor device, comprising a step of attaching the film-shaped adhesive of the above adhesive sheet to a semiconductor wafer, a step of producing a plurality of singulated semiconductor elements with the film-shaped adhesive by cutting the semiconductor wafer to which the film-shaped adhesive is attached, and a step of bonding the semiconductor element with the film-shaped adhesive to a support member.

Advantages of the Invention

[0016] According to the present invention, there is provided a film-shaped adhesive excellent in fragmentation due to cooling expansion. Further, according to the present invention, there are provided an adhesive sheet and a semiconductor device using such a film-shaped adhesive. Furthermore, according to the present invention, there is provided a method for manufacturing a semiconductor device using the film-shaped adhesive or the adhesive sheet.

Brief Description of the Drawings

[0017] [Figure 1] It is a schematic cross-sectional view showing an embodiment of the film-shaped adhesive. [Figure 2] It is a perspective view schematically showing a sample in a state fixed to a jig. [Figure 3] It is a cross-sectional view schematically showing a state in which a load is applied to a sample by a pushing jig. [Figure 4] It is a graph schematically showing an example of the result of a cutting test. [Figure 5] It is a schematic cross-sectional view showing an embodiment of the adhesive sheet. [Figure 6] It is a schematic cross-sectional view showing another embodiment of the adhesive sheet. [Figure 7] It is a schematic cross-sectional view showing another embodiment of the adhesive sheet. [Figure 8] It is a schematic cross-sectional view showing an embodiment of the semiconductor device. [Figure 9] This is a schematic cross-sectional view showing another embodiment of a semiconductor device. [Modes for carrying out the invention]

[0018] Embodiments of the present invention will be described below with reference to the drawings as appropriate. However, the present invention is not limited to the following embodiments. In the following embodiments, the components (including steps, etc.) are not essential unless otherwise specified. The sizes of the components in each figure are conceptual, and the relative relationships of the sizes between components are not limited to those shown in each figure.

[0019] The same applies to numerical values ​​and their ranges in this specification, and they do not limit the present invention. Numerical ranges indicated using "~" in this specification indicate a range that includes the numerical values ​​before and after "~" as the minimum and maximum values, respectively. In numerical ranges described in steps in this specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described in steps. Also, in numerical ranges described in this specification, the upper or lower limit of that numerical range may be replaced with the values ​​shown in the examples.

[0020] In this specification, (meth)acrylate means acrylate or the corresponding methacrylate. The same applies to other similar expressions such as (meth)acryloyl group and (meth)acrylic copolymer.

[0021] A film-like adhesive according to one embodiment is for bonding a semiconductor element to a support member on which the semiconductor element is mounted. The film-like adhesive contains a thermosetting resin (hereinafter sometimes referred to as "component (A)"), a curing agent (hereinafter sometimes referred to as "component (B)"), and an elastomer (hereinafter sometimes referred to as "component (C)"). The film-like adhesive may further contain an inorganic filler (hereinafter sometimes referred to as "component (D)"). The film-like adhesive may further contain a coupling agent (hereinafter sometimes referred to as "component (E)"), a curing accelerator (hereinafter sometimes referred to as "component (F)"), and other components.

[0022] A film-like adhesive can be obtained by forming an adhesive composition containing components (A), (B), and (C), as well as other components added as needed (components (D), (E), (F), and other components, etc.) into a film. The film-like adhesive (adhesive composition) may undergo a semi-cured state (stage B) and then become fully cured (stage C) after a curing treatment.

[0023] (A) Component: Thermosetting resin Component (A) may be an epoxy resin from the viewpoint of adhesion. Examples of epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, stilbene type epoxy resin, triazine skeleton-containing epoxy resin, fluorene skeleton-containing epoxy resin, biphenyl type epoxy resin, xylylene type epoxy resin, biphenyl aralkyl type epoxy resin, naphthalene type epoxy resin, polyfunctional phenols, and diglycidyl ether compounds of polycyclic aromatics such as anthracene. These may be used individually or in combination of two or more. Among these, the epoxy resin may be a cresol novolac type epoxy resin.

[0024] The epoxy equivalent of the epoxy resin is not particularly limited, but may be 90-300 g / eq, 110-290 g / eq, or 110-290 g / eq.

[0025] (B) Component: Hardener Component (B) is a component that acts as a curing agent for component (A). If component (A) is an epoxy resin, component (B) may be a phenolic resin that can act as a curing agent for epoxy resins.

[0026] Phenolic resins can be used without particular limitations as long as they have a phenolic hydroxyl group in their molecule. Examples of phenolic resins include novolac-type phenolic resins obtained by condensing or co-condensing phenols such as phenol, cresol, resorcinol, catechol, bisphenol A, bisphenol F, phenylphenol, aminophenol, and / or naphthols such as α-naphthol, β-naphthol, and dihydroxynaphthalene with compounds having an aldehyde group such as formaldehyde under an acidic catalyst; phenol aralkyl resins synthesized from phenols such as allylated bisphenol A, allylated bisphenol F, allylated naphthalenediol, phenol novolac, and / or naphthols with dimethoxyp-xylene or bis(methoxymethyl)biphenyl; naphthol aralkyl resins; biphenyl aralkyl-type phenolic resins; and phenyl aralkyl-type phenolic resins. These may be used individually or in combination of two or more. Among these, the phenolic resin may be a phenyl aralkyl-type phenolic resin.

[0027] The hydroxyl equivalent of the phenolic resin may be 70 g / eq or more, or 70 to 300 g / eq. When the hydroxyl equivalent of the phenolic resin is 70 g / eq or more, the storage modulus of the film tends to improve further, and when it is 300 g / eq or less, it is possible to prevent problems caused by foaming, outgassing, etc.

[0028] When component (A) is an epoxy resin and component (B) is a phenolic resin, the ratio of the epoxy equivalent of the epoxy resin to the hydroxyl group equivalent of the phenolic resin (epoxy equivalent of epoxy resin / hydroxyl group equivalent of phenolic resin) may be 0.30 / 0.70~0.70 / 0.30, 0.35 / 0.65~0.65 / 0.35, 0.40 / 0.60~0.60 / 0.40, or 0.45 / 0.55~0.55 / 0.45 from the viewpoint of curability. When the equivalent ratio is 0.30 / 0.70 or higher, more sufficient curability tends to be obtained. When the 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 fluidity.

[0029] The total content of component (A) and component (B) may be 5 to 50 parts by mass, 10 to 40 parts by mass, or 15 to 30 parts by mass per 100 parts by mass of the total amount of component (A), component (B), and component (C). When the total content of component (A) and component (B) is 5 parts by mass or more per 100 parts by mass of the total amount of component (A), component (B), and component (C), the elastic modulus tends to improve further through crosslinking. When the total content of component (A) and component (B) is 50 parts by mass or less per 100 parts by mass of the total amount of component (A), component (B), and component (C), the film tends to have better handling properties.

[0030] (C) Ingredients: Elastomer Examples of component (C) include acrylic resin, polyester resin, polyamide resin, polyimide resin, silicone resin, butadiene resin; and modified versions of these resins. These may be used individually or in combination of two or more. Among these, component (C) may be an acrylic resin (acrylic rubber) having constituent units derived from (meth)acrylic acid ester as its main component, as it has fewer ionic impurities, superior heat resistance, easier connection reliability for semiconductor devices, and superior fluidity. The content of constituent units derived from (meth)acrylic acid ester in component (C) may be, for example, 70% by mass or more, 80% by mass or more, or 90% by mass or more, based on the total amount of constituent units. The acrylic resin (acrylic rubber) may contain constituent units derived from (meth)acrylic acid ester having crosslinkable functional groups such as epoxy groups, alcoholic or phenolic hydroxyl groups, or carboxyl groups.

[0031] Among these, component (C) includes an elastomer that satisfies conditions (i) and (ii) (hereinafter sometimes referred to as "component (C1)"). Condition (i): The glass transition temperature is 12°C or higher. Condition (ii): The weight-average molecular weight is 800,000 or less.

[0032] Regarding condition (i), the glass transition temperature (Tg) of component (C1) is 12°C or higher, and may be 15°C or higher, 18°C ​​or higher, or 20°C or higher. When the Tg of component (C) is 12°C or higher, it is possible to further improve the adhesive strength of the film-like adhesive and, furthermore, it tends to prevent the film-like adhesive from becoming too flexible. Therefore, by using such a (C) component, the cleavage of the film-like adhesive in cooled expansion can be improved. There is no particular upper limit to the Tg of component (C1), but for example, it may be 55°C or lower, 50°C or lower, 45°C or lower, 40°C or lower, 35°C or lower, 30°C or lower, or 25°C or lower. When the Tg of component (C) is 55°C or lower, it tends to suppress the decrease in flexibility of the film-like adhesive. This tends to make it easier to adequately fill voids when attaching the film-like adhesive to a semiconductor wafer. It also makes it possible to prevent chipping during dicing due to a decrease in adhesion to the semiconductor wafer. Here, the glass transition temperature (Tg) refers to the value measured using a DSC (Differential Scanning Calorimeter) (for example, Thermo Plus 2 manufactured by Rigaku Corporation). The Tg of component (C) can be adjusted to a desired range by adjusting the type and content of the constituent units that make up component (C) (if component (C) is acrylic resin (acrylic rubber), the constituent units are derived from (meth)acrylic acid ester).

[0033] Regarding condition (ii), the weight-average molecular weight (Mw) of component (C1) is 800,000 or less, but may be 700,000 or less, 600,000 or less, 500,000 or less, 400,000 or less, or 300,000 or less. The lower limit of Mw of component (C1) is not particularly limited, but may be, for example, 10,000 or more, 50,000 or more, or 100,000 or more. When the Mw of component (C1) is within this range, the fragmentation properties, film formation properties, film strength, flexibility, tackiness, etc. in the cooling and expanding of the film can be appropriately controlled, and the reflowability and embedding properties can be improved. Here, Mw refers to the value measured by gel permeation chromatography (GPC) and converted using a calibration curve with standard polystyrene.

[0034] The content of component (C1) may be 50-100% by mass, 70-100% by mass, 90-100% by mass, or 95-100% by mass, based on the total amount of component (C). The content of component (C1) may also be 100% by mass, based on the total amount of component (C).

[0035] Component (C) may include, in addition to component (C1), an elastomer that does not meet the requirements of component (C1) (hereinafter sometimes referred to as "component (C2)").

[0036] The content of component (C2) may be 0-50% by mass, 0-30% by mass, 0-10% by mass, or 0-5% by mass, based on the total amount of component (C). The content of component (C2) may also be 0% by mass, based on the total amount of component (C). In other words, component (C) may not contain component (C2).

[0037] The content of component (C) may be 50 to 95 parts by mass, 60 to 90 parts by mass, or 70 to 85 parts by mass per 100 parts by mass of the total amount of components (A), (B), and (C). When the content of component (C) is within this range, it tends to be possible to obtain a more elastic film and to further increase the die shear strength.

[0038] (D) Ingredients: Inorganic filler Examples of component (D) include aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate whiskers, boron nitride, and silica. These may be used individually or in combination of two or more. Among these, component (D) may be silica from the viewpoint of adjusting the melt viscosity. The shape of component (D) is not particularly limited, but it may be spherical.

[0039] The average particle size of component (D) may be 0.01 to 1 μm, 0.01 to 0.5 μm, 0.01 to 0.3 μm, or 0.01 to 0.1 μm from the viewpoint of fluidity. Here, the average particle size refers to the value obtained by converting from the BET specific surface area.

[0040] The content of component (D) may be 0.1 parts by mass or more, 1 part by mass or more, 3 parts by mass or more, or 5 parts by mass or more, and may be 50 parts by mass or less, 30 parts by mass or less, 20 parts by mass or less, or 15 parts by mass or less, based on 100 parts by mass of the total amount of components (A), (B), and (C).

[0041] (E) Component: Coupling agent Component (E) may be a silane coupling agent. Examples of silane coupling agents include γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, and 3-(2-aminoethyl)aminopropyltrimethoxysilane. These may be used individually or in combination of two or more.

[0042] (F) Ingredient: Curing accelerator Component (F) is not particularly limited and can be any commonly used component. Examples of component (F) include imidazoles and their derivatives, organophosphorus compounds, secondary amines, tertiary amines, quaternary ammonium salts, etc. These may be used individually or in combination of two or more. Among these, from the viewpoint of reactivity, component (F) may be imidazoles and their derivatives.

[0043] Examples of imidazoles include 2-methylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-cyanoethyl-2-methylimidazole. These may be used individually or in combination of two or more.

[0044] The film-like adhesive (adhesive composition) may further contain other components. Examples of other components include pigments, ion capture agents, antioxidants, and the like.

[0045] The total content of component (E), component (F), and other components may be 0 to 30 parts by mass per 100 parts by mass of the total amount of component (A), component (B), and component (C).

[0046] Figure 1 is a schematic cross-sectional view showing one embodiment of a film-like adhesive. The film-like adhesive 1 (adhesive film) shown in Figure 1 is formed by molding an adhesive composition into a film. The film-like adhesive 1 may be in a semi-cured (B-stage) state. Such a film-like adhesive 1 can be formed by applying the adhesive composition to a support film. When using a varnish (adhesive varnish) of the adhesive composition, the adhesive varnish can be prepared by mixing or kneading components (A), (B), and (C), as well as any additional components as needed, in a solvent, applying the obtained adhesive varnish to a support film, and removing the solvent by heating and drying to obtain the film-like adhesive 1.

[0047] The support film is not particularly limited as long as it can withstand the above-mentioned heat drying, but may be, for example, polyester film, polypropylene film, polyethylene terephthalate film, polyimide film, polyetherimide film, polyethylene naphthalate film, polymethylpentene film, etc. The substrate 2 may be a multilayer film made by combining two or more types, and the surface may be treated with a release agent such as silicone or silica. The thickness of the support film may be, for example, 10 to 200 μm or 20 to 170 μm.

[0048] Mixing or kneading can be carried out using conventional agitators, mixers, three-roll mills, ball mills, and other dispersers, in appropriate combinations.

[0049] The solvent used in the preparation of the adhesive varnish is not limited as long as it can uniformly dissolve, knead, or disperse each component, and conventionally known solvents can be used. Examples of such solvents include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, as well as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, toluene, and xylene. From the viewpoint of drying speed and cost, the solvent may be methyl ethyl ketone or cyclohexanone.

[0050] Known methods can be used to apply the adhesive varnish to the support film, including, for example, the knife coating method, roll coating method, spray coating method, gravure coating method, bar coating method, and curtain coating method. Heat drying is not particularly limited as long as the conditions allow the solvent used to evaporate sufficiently, but it can be carried out by heating at 50 to 150°C for 1 to 30 minutes.

[0051] The thickness of the film-like adhesive 1 may be 50 μm or less, 40 μm or less, 30 μm or less, 20 μm or less, or 15 μm or less. The lower limit of the thickness of the film-like adhesive 1 is not particularly limited, but may be, for example, 1 μm or more.

[0052] In a fracture evaluation method using the results of a fracture test performed under the following conditions (a method for evaluating the fracture properties of a film adhesive under low-temperature conditions in which cooling expansion is performed (e.g., in the range of -15°C to 0°C)), the fracture coefficient m of the film adhesive 1 is greater than 0 and 70 or less, and the fracture resistance R is 0 N / mm². 2 Super 40N / mm 2 The following types of film-like adhesives may be used. <Condition> Sample width: 5 mm Sample length: 23 mm Relative speed between the pressing jig and the sample: 10 mm / min

[0053] The fracture test is described below. The fracture test is classified as a flexural strength test and includes the step of pressing the central part of the sample until it breaks while both ends of the sample are fixed. As shown in Figure 2, the sample S is subjected to the fracture test while being fixed between a pair of sample fixing jigs 14. The pair of sample fixing jigs 14 are made of, for example, cardboard with sufficient strength and each has a rectangular opening 14a in the center. A load is applied to the central part of the fixed sample S using a pressing jig 15 (see Figure 3).

[0054] The sample S can be any piece cut from the film-like adhesive to be evaluated, and it is not necessary to prepare the sample by laminating multiple adhesive pieces cut from the film-like adhesive. In other words, the thickness of the sample S may be the same as the thickness of the film-like adhesive. The width of the sample S (Ws in Figure 2) may be, for example, 1 to 30 mm, or 3 to 8 mm. It should be set to an appropriate width depending on the condition of the measuring device. The length of the sample S (Ls in Figure 2) may be, for example, 5 to 50 mm, or 10 to 30 mm or 6 to 9 mm. The length of the sample S depends on the size of the opening 14a of the sample fixing jig 14. Note that the shape of the sample fixing jig 14 and the size of the sample S may be other than those described above, as long as the cleavage test can be performed.

[0055] The pressing jig 15 consists of a cylindrical member having a conical tip 15a. The diameter of the pressing jig 15 (R in Figure 3) is, for example, 3 to 15 mm, or may be 5 to 10 mm. The angle of the tip 15a (θ in Figure 3) is, for example, 40 to 120°, or may be 60 to 100°.

[0056] The cleavage test is performed in a constant temperature chamber set to a predetermined temperature. The constant temperature chamber should be set to a constant temperature in the range of -15°C to 0°C (the temperature of the expected cooled expander). For example, the TLF-R3-FW-PL-S manufactured by ITEC Corporation can be used as the constant temperature chamber. An autograph (for example, AZT-CA01 manufactured by A&D Corporation, load cell 50N, compression mode) is used to obtain the cleavage work W, cleavage strength P, and cleavage elongation L.

[0057] The relative speed between the pressing jig 15 and the sample S is, for example, 1 to 100 mm / min, and may be 5 to 20 mm / min. If this relative speed is too fast, data in the cutting process tends not to be fully obtained, and if it is too slow, the stress tends to relax and it is difficult to reach cutting. The pressing distance of the pressing jig 15 is, for example, 1 to 50 mm, and may be 5 to 30 mm. If the pressing distance is too short, it tends not to reach cutting. For the film-like adhesive to be evaluated, it is preferable to prepare a plurality of samples and perform the cutting test a plurality of times to confirm the stability of the test results.

[0058] FIG. 4 is a graph showing an example of the results of the cutting test. As shown in FIG. 4, the cutting work W is the area enclosed when a graph is created with the vertical axis being the load and the horizontal axis being the amount of pressing until the sample S breaks. The cutting strength P is the load when the sample S breaks. The cutting elongation L is the amount of elongation of the sample S when the sample S breaks. The cutting elongation L may be calculated using a trigonometric function from the pressing distance when the sample S breaks and the width of the opening 14a of the sample fixing jig 14.

[0059] From the values of the cutting work W (N·mm), cutting strength P (N), and cutting elongation L (mm) obtained by the cutting test, the cutting coefficient m (dimensionless) and cutting resistance R (N / mm 2 ) are obtained from Equation (1) and Equation (2). m = W / [1000×(P×L)] (1) R = P / A (2)

[0060] According to the study by the present inventors, when the cutting test is carried out under the following conditions, the cutting coefficient m is more than 0 and 70 or less, and the cutting resistance R is more than 0 N / mm 2 and less than 40 N / mm 2 The following film-like adhesives tend to be excellent in the disconnection property when actually cooled and expanded in stealth dicing. <Conditions> Width of sample: 5 mm Length of sample: 23 mm Relative speed between pressing jig and sample: 10 mm / min

[0061] The fracture coefficient m (dimensionless) may be greater than 0 and less than or equal to 70, and may be between 10 and 60 or between 15 and 55, as described above. The fracture coefficient m is a parameter relating to the stretchability of the film-like adhesive under low-temperature conditions. When the fracture coefficient m exceeds 70, the excessive stretchability of the film-like adhesive tends to result in insufficient separation by cooling and expanding. Furthermore, when the fracture coefficient m is 15 or greater, stress propagation tends to be good. The fracture resistance R is 0 N / mm 2 Super 40N / mm 2 The following may be true: 0 N / mm 2 Super 35N / mm 2 The following or 1-30 N / mm² 2 This is also acceptable. The split resistance R is 40 N / mm 2 Beyond this point, the excessive strength of the film-like adhesive tends to result in insufficient separation by cooling and expanding. Note that the fracture resistance R is 20 N / mm². 2 When these conditions are met, better stress propagation in the cooled expanded state tends to result in even superior dicing properties due to the cooled expanded state. Film-like adhesives with a cleavage coefficient m and cleavage resistance R within the above range can be suitably used for stealth dicing. Film-like adhesives with a cleavage coefficient m and cleavage resistance R within the above range can be applied to the manufacturing process of semiconductor devices in which cooled expanded state is performed.

[0062] Figure 5 is a schematic cross-sectional view showing one embodiment of an adhesive sheet. The adhesive sheet 100 shown in Figure 5 comprises a base material 2 and a film-like adhesive 1 provided on the base material 2. Figure 6 is a schematic cross-sectional view showing another embodiment of an adhesive sheet. The adhesive sheet 110 shown in Figure 6 comprises a base material 2, a film-like adhesive 1 provided on the base material 2, and a cover film 3 provided on the side of the film-like adhesive 1 opposite to the base material 2.

[0063] The base material 2 can be the same as the support film described above.

[0064] The cover film 3 is used to prevent damage to or contamination of the film-like adhesive and may be, for example, a polyethylene film, a polypropylene film, or a film treated with a surface release agent. The thickness of the cover film 3 may be, for example, 15 to 200 μm or 70 to 170 μm.

[0065] The adhesive sheets 100 and 110 can be formed by applying an adhesive composition (adhesive varnish) to the substrate 2, similar to the method for forming the film-like adhesive described above. The method for applying the adhesive composition to the substrate 2 may be the same as the method for applying the adhesive composition (adhesive varnish) to the support film described above.

[0066] The adhesive sheet 110 can be obtained by further laminating a cover film 3 onto the film-like adhesive 1.

[0067] The adhesive sheets 100 and 110 can be formed using a pre-made film-like adhesive. In this case, the adhesive sheet 100 can be formed by laminating it onto the substrate 2 under predetermined conditions (for example, at room temperature (20°C) or in a heated state) using a roll laminator, vacuum laminator, etc. The adhesive sheet 100 can be manufactured continuously and is highly efficient, so it may also be formed using a roll laminator in a heated state.

[0068] Another embodiment of the adhesive sheet is a dicing-die bonding integrated adhesive sheet in which the substrate 2 is a dicing tape. Figure 7 is a schematic cross-sectional view showing another embodiment of the adhesive sheet. The adhesive sheet 120 (dicing-die bonding integrated adhesive sheet) shown in Figure 7 comprises a dicing tape 8 and a film-like adhesive 1 provided on the dicing tape 8. Using a dicing-die bonding integrated adhesive sheet allows for a single lamination process on the semiconductor wafer, thus improving work efficiency.

[0069] In one embodiment, the dicing tape 8 comprises a base film 7 and an adhesive layer 6 provided on the base film 7.

[0070] Examples of the base film 7 include plastic films such as polytetrafluoroethylene film, polyethylene terephthalate film, polyethylene film, polypropylene film, polymethylpentene film, and polyimide film. These base films 7 may be subjected to surface treatments such as primer application, UV treatment, corona discharge treatment, polishing treatment, and etching treatment as needed.

[0071] The adhesive layer 6 is not particularly limited as long as it has sufficient adhesive strength to prevent the semiconductor elements from scattering during dicing and low enough adhesive strength to avoid damaging the semiconductor elements during the subsequent semiconductor element pickup process; conventionally known adhesive layers in the field of dicing tapes can be used. The adhesive layer 6 may be either pressure-sensitive or radiation-curable.

[0072] The thickness of the dicing tape 8 (base film 7 and adhesive layer 6) may be 60-150 μm or 70-130 μm from the viewpoint of economy and ease of handling of the film.

[0073] The adhesive sheet 120 (dicing / die bonding integrated adhesive sheet) can be obtained, for example, by bonding the adhesive layer 6 of the dicing tape 8 with the film-like adhesive 1.

[0074] The film-like adhesive and adhesive sheet may be used in the manufacture of semiconductor devices, and may be used in the manufacture of semiconductor devices that include the process of bonding the film-like adhesive and dicing tape to a semiconductor wafer or already individualized semiconductor elements (semiconductor chips) at 0°C to 90°C, obtaining a semiconductor element with the film-like adhesive by cutting with a rotating blade, laser, or stretching, and then bonding the semiconductor element with the film-like adhesive to an organic substrate, lead frame, or other semiconductor elements.

[0075] Examples of semiconductor wafers include single-crystal silicon, polycrystalline silicon, various ceramics, and compound semiconductors such as gallium arsenide.

[0076] Film-type adhesives and adhesive sheets can be used as adhesives for bonding semiconductor elements such as ICs and LSIs to lead frames such as 42 alloy lead frames and copper lead frames; plastic films such as polyimide resin and epoxy resin; substrates such as glass nonwoven fabric impregnated and cured with plastics such as polyimide resin and epoxy resin; and semiconductor mounting support members such as ceramics such as alumina.

[0077] Film-like adhesives and adhesive sheets are also suitably used as adhesives for bonding semiconductor elements together in stacked packages with a structure in which multiple semiconductor elements are stacked. In this case, one of the semiconductor elements becomes a support member on which the semiconductor element is mounted.

[0078] The film-like adhesive and adhesive sheet can also be used, for example, as a protective sheet to protect the back surface of a semiconductor element in a flip-chip semiconductor device, or as a sealing sheet to seal the space between the surface of a semiconductor element in a flip-chip semiconductor device and the adherend.

[0079] A semiconductor device manufactured using a film-type adhesive will be described in detail below with reference to the drawings. It should be noted that various structures of semiconductor devices have been proposed in recent years, and the applications of the film-type adhesive according to this embodiment are not limited to the semiconductor device with the structure described below.

[0080] Figure 8 is a schematic cross-sectional view showing one embodiment of a semiconductor device. The semiconductor device 200 shown in Figure 8 comprises a semiconductor element 9, a support member 10 on which the semiconductor element 9 is mounted, and an adhesive member (cured film adhesive 1c) provided between the semiconductor element 9 and the support member 10 to bond the semiconductor element 9 and the support member 10. The connection terminal (not shown) of the semiconductor element 9 is electrically connected to an external connection terminal (not shown) via a wire 11 and is sealed by a sealing material 12.

[0081] Figure 9 is a schematic cross-sectional view showing another embodiment of a semiconductor device. In the semiconductor device 210 shown in Figure 9, the first semiconductor element 9a is bonded to a support member 10 on which terminals 13 are formed by an adhesive member (cured film adhesive 1c), and the second semiconductor element 9b is further bonded to the first semiconductor element 9a by an adhesive member (cured film adhesive 1c). The connection terminals (not shown) of the first semiconductor element 9a and the second semiconductor element 9b are electrically connected to an external connection terminal via a wire 11 and sealed by a sealing material 12. Thus, the film adhesive according to this embodiment can be suitably used in semiconductor devices with a structure in which multiple semiconductor elements are stacked.

[0082] The semiconductor device (semiconductor package) shown in Figures 8 and 9 can be obtained, for example, by interposing a film-like adhesive between a semiconductor element and a support member or between two semiconductor elements, bonding them together by heating and pressing, and then, if necessary, going through a wire bonding process, a sealing process with a sealing material, a heating and melting process including reflow soldering, etc. The heating temperature in the heating and pressing process is usually 20 to 250°C, the load is usually 0.1 to 200 N, and the heating time is usually 0.1 to 300 seconds.

[0083] As a method for interposing a film-like adhesive between a semiconductor element and a support member or between semiconductor elements, as described above, a method may be used in which a semiconductor element with a film-like adhesive attached is manufactured in advance and then attached to the support member or semiconductor element.

[0084] Next, an embodiment of a method for manufacturing a semiconductor device using the dicing-die bonding integrated adhesive sheet shown in Figure 7 will be described. Note that the method for manufacturing a semiconductor device using the dicing-die bonding integrated adhesive sheet is not limited to the method described below.

[0085] First, the semiconductor wafer is pressed onto the film-like adhesive 1 in the adhesive sheet 120 (dicing / die bonding integrated adhesive sheet) to hold and fix it in place (mounting process). This process may be carried out while pressing with a pressing means such as a pressure roll.

[0086] Next, the semiconductor wafer is diced. This cuts the semiconductor wafer into predetermined sizes to produce multiple individual pieces of semiconductor elements (semiconductor chips) with adhesive film. Dicing can be performed, for example, from the circuit side of the semiconductor wafer according to conventional methods. In this process, various cutting methods can be employed, such as a full-cut method that cuts all the way to the dicing tape, a method that cuts halfway through the semiconductor wafer and then cools and pulls it to separate it, or a laser cutting method. The dicing apparatus used in this process is not particularly limited, and conventionally known apparatuses can be used.

[0087] To remove semiconductor elements that are bonded and fixed to a dicing-die bonding integrated adhesive sheet, the semiconductor elements are picked up. The method of pickup is not particularly limited, and various conventionally known methods can be employed. For example, one method involves pushing up individual semiconductor elements from the dicing-die bonding integrated adhesive sheet side with a needle, and then picking up the pushed-up semiconductor elements with a pickup device.

[0088] In this case, if the adhesive layer is radiation-curable (e.g., ultraviolet light), the pickup is performed after irradiating the adhesive layer with radiation. This reduces the adhesive strength of the adhesive layer to the film-like adhesive, making it easier to peel off the semiconductor device. As a result, pickup becomes possible without damaging the semiconductor device.

[0089] Next, the semiconductor element with film-like adhesive formed by dicing is bonded to a support member for mounting the semiconductor element via the film-like adhesive. Bonding may be performed by pressure. The conditions for die bonding are not particularly limited and can be set as appropriate. Specifically, for example, it can be performed within the range of a die bonding temperature of 80 to 160°C, a bonding load of 5 to 15 N, and a bonding time of 1 to 10 seconds.

[0090] If necessary, a step of heat-curing the film-like adhesive may be included. By heat-curing the film-like adhesive that bonds the support member and the semiconductor element in the above bonding step, stronger adhesion and fixation can be achieved. When heat-curing, pressure may be applied simultaneously to cure the adhesive. The heating temperature in this step can be appropriately changed depending on the components of the film-like adhesive. The heating temperature may be, for example, 60 to 200°C. Note that the temperature or pressure may be changed in stages.

[0091] Next, a wire bonding process is performed to electrically connect the tip of the terminal portion (inner lead) of the support member to the electrode pad on the semiconductor element using a bonding wire. Examples of bonding wires include gold wire, aluminum wire, and copper wire. The temperature during wire bonding may be within the range of 80 to 250°C or 80 to 220°C. The heating time may be from a few seconds to a few minutes. The connection may be made by combining ultrasonic vibration energy and applied pressure to create a crimping energy while the wire is heated within the above temperature range.

[0092] Next, a sealing process is performed in which the semiconductor element is sealed with a sealing resin. This process is performed to protect the semiconductor element or bonding wire mounted on the support member. This process is performed by molding the sealing resin in a mold. The sealing resin may be, for example, an epoxy resin. The heat and pressure during sealing embed the substrate and residue, preventing delamination due to air bubbles at the adhesive interface.

[0093] Next, in the post-curing step, the sealing resin that was not sufficiently cured in the sealing step is completely cured. Even if the film adhesive is not heat-cured in the sealing step, in this step, the film adhesive is heat-cured along with the sealing resin, enabling adhesive fixation. The heating temperature in this step can be appropriately set depending on the type of sealing resin, for example, it may be in the range of 165 to 185°C, and the heating time may be about 0.5 to 8 hours.

[0094] Next, the semiconductor element with film-like adhesive attached to the support member is heated using a reflow oven. In this step, the resin-encapsulated semiconductor device may be surface-mounted onto the support member. Examples of surface mounting methods include reflow soldering, in which solder is supplied onto a printed circuit board beforehand, then heated and melted with hot air or the like to perform soldering. Examples of heating methods include hot air reflow and infrared reflow. The heating method may involve heating the entire device or heating only a specific area. The heating temperature may be, for example, in the range of 240 to 280°C. [Examples]

[0095] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples.

[0096] [Preparation of film-like adhesives] (Examples 1-6 and Comparative Example 1) <Preparation of adhesive varnish> Cyclohexanone was added to a composition consisting of components (A), (B), and (D) in the quantities (parts by mass) shown in Table 1, and stirred. Then, component (C) (component (C1) or (C2)) was added and stirred, and then components (E) and (F) were added and stirred until all components were homogeneous to prepare the adhesive varnish. Note that the numerical values ​​for component (C) shown in Table 1 represent parts by mass of solids.

[0097] The components shown in Table 1 refer to the following:

[0098] (A) Component: Thermosetting resin (A-1) YDCN-700-10 (Product name, manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., o-cresol novolac type epoxy resin, epoxy equivalent: 209 g / eq)

[0099] (B) Component: Hardener (B-1) HE-100C-30 (Product name, manufactured by Air Water Inc., phenyl aralkyl type phenolic resin, hydroxyl group equivalent: 174 g / eq, softening point 77°C)

[0100] (C) Ingredients: Elastomer (C1) Component: Elastomer satisfying conditions (i) and (ii) (C1-1) Acrylic rubber solution (An acrylic rubber solution in which some of the constituent units of the acrylic rubber in SG-P3 (product name, manufactured by Nagase ChemteX Corporation, methyl ethyl ketone solution of acrylic rubber) have been modified; measured Tg of acrylic rubber: 20℃; weight-average molecular weight of acrylic rubber: 800,000) (C1-2) Acrylic rubber solution (An acrylic rubber solution in which some of the constituent units of the acrylic rubber in SG-P3 (product name, manufactured by Nagase ChemteX Corporation, methyl ethyl ketone solution of acrylic rubber) have been modified; measured Tg of acrylic rubber: 25°C; weight-average molecular weight of acrylic rubber: 800,000) (C1-3) Acrylic rubber solution (An acrylic rubber solution in which some of the constituent units of the acrylic rubber in SG-P3 (product name, manufactured by Nagase ChemteX Corporation, methyl ethyl ketone solution of acrylic rubber) have been modified; measured Tg of acrylic rubber: 12℃; weight-average molecular weight of acrylic rubber: 500,000) (C1-4) Acrylic rubber solution (An acrylic rubber solution in which some of the constituent units of the acrylic rubber in SG-P3 (product name, manufactured by Nagase ChemteX Corporation, methyl ethyl ketone solution of acrylic rubber) have been modified; measured Tg of acrylic rubber: 20°C; weight-average molecular weight of acrylic rubber: 500,000) (C1-5) Acrylic rubber solution (An acrylic rubber solution in which some of the constituent units of the acrylic rubber in SG-P3 (product name, manufactured by Nagase ChemteX Corporation, methyl ethyl ketone solution of acrylic rubber) have been modified; measured Tg of acrylic rubber: 20°C; weight-average molecular weight of acrylic rubber: 200,000) (C2) component: Elastomer other than (C1) component (C2-1) Acrylic rubber solution (An acrylic rubber solution in which some of the constituent units of the acrylic rubber in SG-P3 (product name, manufactured by Nagase ChemteX Corporation, methyl ethyl ketone solution of acrylic rubber) have been modified; measured Tg of acrylic rubber: 3℃; weight-average molecular weight of acrylic rubber: 800,000)

[0101] (D) Ingredients: Inorganic filler (D-1) R972 (Product name, manufactured by Nippon Aerosil Co., Ltd., silica particles, average particle size: 0.016 μm)

[0102] (E) Component: Coupling agent (E-1) A-189 (Product name, manufactured by Nippon Unicar Co., Ltd., γ-mercaptopropyltrimethoxysilane) (E-2) A-1160 (Product name, manufactured by Nippon Unicar Co., Ltd., γ-ureidopropyltriethoxysilane)

[0103] (F) Ingredient: Curing accelerator (F-1)2PZ-CN (product name, manufactured by Shikoku Chemicals, Inc., 1-cyanoethyl-2-phenylimidazole)

[0104] <Preparation of film-like adhesives> The prepared adhesive varnish was filtered through a 100-mesh filter and degassed under vacuum. A 38 μm thick polyethylene terephthalate (PET) film with a release treatment was prepared as the substrate, and the degassed adhesive varnish was applied to the PET film. The applied adhesive varnish was heated and dried in two stages: 90°C for 5 minutes, followed by 130°C for 5 minutes, to obtain the film-like adhesives of Examples 1-3 and Comparative Example 1, which were in the B-stage state. In the film-like adhesives, the thickness of the film-like adhesive was adjusted to 10 μm by controlling the amount of adhesive varnish applied.

[0105] <Evaluation of the fragmentation properties of film-like adhesives by cooling and expanding> Adhesive strips (5 mm wide x 100 mm long) were cut from the film-like adhesives of Examples 1-6 and Comparative Example 1. The adhesive strips were fixed to a pair of jigs (cardboard), and any portion of the adhesive strip protruding from the jigs was removed. This obtained the samples to be evaluated (5 mm wide x 23 mm long). A fracture test was performed in a constant temperature chamber (ITEC Corporation, TLF-R3-FW-PL-S) set to predetermined temperature conditions. Specifically, a fracture test was performed using an Autograph (A&D Corporation, AZT-CA01, load cell 50N) in compression mode, at a speed of 10 mm / min, and with a pressing distance of 5 mm, to determine the work of fracture W, fracture strength P, and fracture elongation L when the film-like adhesive fractured. The fracture coefficient m and fracture resistance R were calculated using equations (1) and (2) above. At least eight fracture tests were performed for each example and comparative example. The results are shown in Table 1. The values ​​listed in Table 1 are the average values ​​obtained from multiple cleavage tests.

[0106] To confirm that the intercalation evaluation matches the intercalation in cooled expanded films, dicing-die bonding integrated films equipped with the film-like adhesives of Examples 1-6 and Comparative Example 1 as adhesive layers were prepared, and the intercalation of the adhesive layer (film-like adhesive) was evaluated under the following conditions. • Silicon wafer thickness: 30 μm • Chip size for individual pieces produced by stealth dicing: 10mm (vertical) x 10mm (horizontal) • Temperature of the cooled expander: Same temperature as the constant temperature bath used for the cleavage test in the examples and comparative examples. • Push-up by the expander ring: 10mm • Evaluation Criteria: Light was shone onto the silicon wafer after it had been pushed up by the expansion ring. Those where light could pass between adjacent adhesive chips (indicating separation of the silicon wafer and adhesive layer) were evaluated as "A," and those where there were areas where light could not pass (indicating separation of the silicon wafer and adhesive layer) were evaluated as "B." The results are shown in Table 1.

[0107] [Table 1]

[0108] As shown in Table 1, the film-like adhesives of Examples 1 to 6 have a fracture coefficient m of 70 or less and a fracture resistance R of 40 N / mm². 2 The following was observed, and the evaluation of the cleavage resistance by cooling and expanding was "A". In contrast, the film-like adhesive of Comparative Example 1 had a cleavage coefficient m of over 70 and a cleavage resistance R of 40 N / mm 2 The result was "B" in terms of detachability by cooling and expanding. These results confirm that the film-like adhesive of the present invention exhibits excellent detachability by cooling and expanding. [Explanation of Symbols]

[0109] 1...Film-like adhesive, 2...Substrate, 3...Cover film, 6...Adhesive layer, 7...Substrate film, 8...Dicing tape, 9,9a,9b...Semiconductor element, 10...Support member, 11...Wire, 12...Sealing material, 13...Terminal, 14...Sample fixing jig, 14a...Opening, 15...Pushing jig, 15a...Tip, 100,110,120...Adhesive sheet, 200,210...Semiconductor device, S...Sample.

Claims

1. A film-like adhesive for bonding a semiconductor element to a support member on which the semiconductor element is mounted, The aforementioned film-like adhesive contains a thermosetting resin, a curing agent, and an elastomer. The thermosetting resin is an epoxy resin. The curing agent is a phenolic resin, The elastomer is made of acrylic rubber that satisfies the following conditions (i) and (ii), A film-like adhesive applied to a method of cutting a semiconductor wafer by performing a process to easily separate the semiconductor wafer, and then expanding the outer periphery in a temperature range of -15°C to 0°C. Condition (i): The glass transition temperature is between 20°C and 30°C. Condition (ii): The weight-average molecular weight is between 100,000 and 800,000.

2. The film-like adhesive according to claim 1, wherein the film-like adhesive further contains an inorganic filler.

3. Substrate and A film-like adhesive according to claim 1 or 2 is provided on one surface of the substrate, An adhesive sheet equipped with [the necessary features].

4. The adhesive sheet according to claim 3, wherein the base material is a dicing tape.

5. Semiconductor elements and A support member on which the semiconductor element is mounted, An adhesive member is provided between the semiconductor element and the support member to bond the semiconductor element and the support member, Equipped with, A semiconductor device wherein the adhesive member is a cured product of the film-like adhesive described in claim 1 or 2.

6. A method for manufacturing a semiconductor device, comprising the step of bonding a semiconductor element and a support member using a film-like adhesive according to claim 1 or 2.

7. A step of attaching the film-like adhesive of the adhesive sheet according to claim 3 or 4 to a semiconductor wafer, A step of producing a plurality of individual pieces of semiconductor elements with film-like adhesive by cutting the semiconductor wafer to which the film-like adhesive has been attached, The process of bonding the film-like adhesive-coated semiconductor element to a support member, A method for manufacturing a semiconductor device, comprising:

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