Filmy adhesive, adhesive sheet, and semiconductor device and production method therefor

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, a semiconductor device, and a method for manufacturing the same.

Background Art

[0002] In recent years, stacked MCP (Multi Chip Package) in which semiconductor elements (semiconductor chips) are stacked in multiple stages has become widespread and is mounted as a memory semiconductor package for mobile phones, portable audio devices, and the like. Further, with the multifunctionalization of mobile phones and the like, the high speed, high density, high integration, etc. of semiconductor packages are also being promoted.

[0003] Currently, as a method for manufacturing a semiconductor device, a semiconductor wafer backside attachment method in which a film-like adhesive and a dicing tape are attached to the backside of a semiconductor wafer, and then a part of the semiconductor wafer, the film-like adhesive, and the dicing tape are cut in a dicing process is generally used. In such a method, it is necessary to cut the film-like adhesive simultaneously when dicing the semiconductor wafer. However, in a general dicing method using a diamond blade, since the semiconductor wafer and the film-like adhesive are cut simultaneously, it is necessary to slow down the cutting speed, which may lead to an increase in cost.

[0004] On the other hand, as a method for dividing a semiconductor wafer, a method of irradiating a laser beam inside the semiconductor wafer on a planned cutting line to form a modified region, etc., a process for easily dividing the semiconductor wafer is performed, and then the semiconductor wafer is cut by expanding the outer peripheral portion has been proposed in recent years (for example, Patent Document 1). This method is called stealth dicing. Stealth dicing has an effect of reducing defects such as chipping particularly when the thickness of the semiconductor wafer is thin, and an improvement effect in yield and the like can be expected.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-192370 [Summary of the Invention] [Problems to be Solved by the Invention]

[0006] However, since the film-like adhesive is flexible and easy to stretch, it tends to be difficult to be cut by the expansion of the dicing tape. In order to improve the cuttability due to the expansion of the film-like adhesive (especially the cooling expansion at a low temperature (for example, in the range of -15°C to 0°C)), it is necessary to increase the expansion amount of the dicing tape. However, increasing the expansion amount may increase the amount of deflection of the dicing tape, which may have an adverse effect on subsequent transport processes and the like.

[0007] The present invention has been made in view of the above circumstances, and the main object thereof is to provide a film-like adhesive excellent in cuttability due to cooling expansion. [Means for Solving the Problems]

[0008] One aspect of the present invention provides a film-like adhesive for bonding a semiconductor element and 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 condition (i) and the following condition (ii). Such a film-like adhesive can be excellent in cuttability due to 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] According to the studies of the present inventors, it has been found that in a film-like adhesive, the flexibility of the film-like adhesive tends to be suppressed by using a specific elastomer. Therefore, the present inventors believe that by using such a specific elastomer, the excessive improvement in the flexibility of the film-like adhesive can be suppressed, and as a result, the breakability of the film-like adhesive in cooling expansion can be improved.

[0010] The film-like adhesive includes a step of preparing a sample having a cross-sectional area A (mm 2 ) from the film-like adhesive, a step of obtaining the cutting work W (N·mm), the cutting strength P (N), and the cutting elongation L (mm) of the sample by a cutting test under low-temperature conditions in the range of -15°C to 0°C, a step of obtaining the cutting coefficient m represented by the following formula (1), and a step of obtaining the cutting resistance R (N / mm 2 ) represented by the following formula (2). In the breakability evaluation method 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 40 N / mm 2 or less. It may be a film-like adhesive. m = W / [1000×(P×L)] (1) R = P / A (2) <Condition> Width of the sample: 5 mm Length of the sample: 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 provides an adhesive sheet including a base material and the above film-like adhesive provided on one surface of the base material.

[0013] Another aspect of the present invention provides a semiconductor device including 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 film-like adhesive.

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

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

Advantages of the Invention

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

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described with appropriate reference to the drawings. 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 size relationships between the components are not limited to those shown in each figure.

[0019] The same applies to the numerical values and ranges thereof in this specification, and they do not limit the present invention. The numerical range indicated by "~" in this specification indicates a range including the numerical values described before and after "~" as the minimum value and the maximum value, respectively. In the numerical ranges described stepwise in this specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another numerically described range. Also, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value 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, (meth)acrylic copolymer, etc.

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

[0022] The film - like adhesive can be obtained by forming into a film shape an adhesive composition containing component (A), component (B), and component (C), and other components (component (D), component (E), component (F), and other components, etc.) added as necessary. The film - like adhesive (adhesive composition) may be one that can reach a fully cured (C - stage) state after a curing treatment through a semi - cured (B - stage) state.

[0023] (A) component: Thermosetting resin (A) component may be an epoxy resin from the viewpoint of adhesiveness. Examples of the epoxy resin 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, 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 cresol novolac type epoxy resin.

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

[0025] Component (B): Curing agent Component (B) is a component that acts as a curing agent for component (A). When component (A) is an epoxy resin, component (B) may be a phenolic resin that can be a curing agent for the epoxy resin.

[0026] The phenolic resin can be used without particular limitation as long as it has phenolic hydroxyl groups in the molecule. Examples of phenolic resins include novolak-type phenolic resins obtained by condensing or co-condensing phenols such as phenol, cresol, resorcinol, catechol, bisphenol A, bisphenol F, phenylphenol, aminophenol, etc. and / or naphthols such as α-naphthol, β-naphthol, dihydroxynaphthalene, etc. with compounds having aldehyde groups such as formaldehyde under an acidic catalyst, allylated bisphenol A, allylated bisphenol F, allylated naphthalenediol, phenolic novolak, phenolic resins such as phenol and / or naphthols, and phenolic aralkyl resins, naphthol aralkyl resins, biphenyl aralkyl-type phenolic resins, phenyl aralkyl-type phenolic resins, etc. synthesized from dimethoxyparaxylene or bis(methoxymethyl)biphenyl. These may be used alone 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 be further improved, and when it is 300 g / eq or less, it is possible to prevent problems caused by the generation of 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 equivalent of the phenolic resin (epoxy equivalent of epoxy resin / hydroxyl equivalent of phenolic resin) 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 from the viewpoint of curability. When the equivalent ratio is 0.30 / 0.70 or more, sufficient curability tends to be obtained. When the equivalent ratio is 0.70 / 0.30 or less, it is possible to prevent the viscosity from becoming too high and 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 with respect to 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 with respect to 100 parts by mass of the total amount of component (A), component (B), and component (C), the elastic modulus tends to be further improved by crosslinking. When the total content of component (A) and component (B) is 50 parts by mass or less with respect to 100 parts by mass of the total amount of component (A), component (B), and component (C), the film handling property tends to be more excellent.

[0030] Component (C): Elastomer Examples of component (C) include acrylic resins, polyester resins, polyamide resins, polyimide resins, silicone resins, butadiene resins; modified products of these resins, and the like. These may be used alone or in combination of two or more. Among these, component (C) may be an acrylic resin (acrylic rubber) having a structural unit derived from a (meth)acrylic acid ester as a main component because it has few ionic impurities and is excellent in heat resistance, is more likely to ensure the connection reliability of the semiconductor device, and is excellent in fluidity. The content of the structural unit derived from the (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 the structural units. The acrylic resin (acrylic rubber) may contain 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 carboxyl group.

[0031] Among these, component (C) includes an elastomer that satisfies condition (i) and condition (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 the 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 the component (C) is 12°C or higher, it becomes possible to further improve the adhesive strength of the film-like adhesive, and furthermore, it tends to be possible to prevent the flexibility of the film-like adhesive from becoming too high. Therefore, by using such a component (C), the breakability of the film-like adhesive in cooling expansion can be improved. The upper limit of the Tg of the component (C1) is not particularly limited, and may be, for example, 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 the component (C) is 55°C or lower, it tends to be possible to suppress a decrease in the flexibility of the film-like adhesive. As a result, when the film-like adhesive is attached to a semiconductor wafer, it tends to be easier to sufficiently embed voids. Also, it becomes possible to prevent chipping during dicing due to a decrease in the adhesion to the semiconductor wafer. Here, the glass transition temperature (Tg) means a value measured using a DSC (Differential Scanning Calorimeter) (for example, manufactured by Rigaku Corporation, Thermo Plus 2). The Tg of the component (C) can be adjusted to a desired range by adjusting the types and contents of the structural units constituting the component (C) (when the component (C) is an acrylic resin (acrylic rubber), the structural units derived from (meth)acrylic acid esters).

[0033] Regarding condition (ii), the weight average molecular weight (Mw) of the component (C1) is 800,000 or lower, and may be 700,000 or lower, 600,000 or lower, 500,000 or lower, 400,000 or lower, or 300,000 or lower. The lower limit of the Mw of the component (C1) is not particularly limited, and may be, for example, 10,000 or higher, 50,000 or higher, or 100,000 or higher. When the Mw of the component (C1) is in such a range, the breakability, film-forming property, film strength, flexibility, tackiness, etc. in the cooling expansion of the film can be appropriately controlled, and it has excellent reflowability and can improve the embedding property. Here, Mw means a value measured by gel permeation chromatography (GPC) and converted using a calibration curve with standard polystyrene.

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

[0035] In addition to component (C1), component (C) may contain an elastomer that does not meet the requirements of component (C1) (hereinafter sometimes referred to as “component (C2)”).

[0036] (C2) component content may be 0 to 50% by mass, 0 to 30% by mass, 0 to 10% by mass, or 0 to 5% by mass based on the total amount of component (C). The content of component (C2) may be 0% by mass based on the total amount of component (C). That is, component (C) may not contain component (C2).

[0037] (C) component content may be 50 to 95 parts by mass, 60 to 90 parts by mass, or 70 to 85 parts by mass with respect to 100 parts by mass of the total amount of components (A), (B), and (C). When the content of component (C) is in such a range, a higher elastic film can be obtained, and the die share strength tends to be further increased.

[0038] (D) component: 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 whisker, boron nitride, silica, etc. These may be used alone 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 may be spherical.

[0039] (D) component's average particle size 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 means a value obtained by conversion from the BET specific surface area.

[0040] (D) component's content may be 0.1 part 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 with respect to 100 parts by mass of the total amount of (A) component, (B) component, and (C) component.

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

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

[0043] Examples of imidazoles include 2-methylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, etc. These may be used alone 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 scavengers, antioxidants, and the like.

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

[0046] FIG. 1 is a schematic cross-sectional view showing an embodiment of the film-like adhesive. The film-like adhesive 1 (adhesive film) shown in FIG. 1 is obtained by forming an adhesive composition into a film shape. 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 an adhesive composition to a support film. When using a varnish of the adhesive composition (adhesive varnish), the (A) component, (B) component, and (C) component, and components added as necessary are mixed or kneaded in a solvent to prepare an adhesive varnish, and the obtained adhesive varnish is applied to a support film. The film-like adhesive 1 can be obtained by heating and drying to remove the solvent.

[0047] The support film is not particularly limited as long as it can withstand the above heat drying. For example, it may be a polyester film, a polypropylene film, a polyethylene terephthalate film, a polyimide film, a polyetherimide film, a polyethylene naphthalate film, a polymethylpentene film, or the like. The base material 2 may be a multilayer film combining two or more kinds, or may be a surface treated with a release agent such as a silicone-based or silica-based release agent. 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 performed by using a normal stirrer, a disperser such as a kneader, a three-roll mill, or a ball mill, and appropriately combining these.

[0049] The solvent used for preparing 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, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, toluene, xylene, and the like. The solvent may be methyl ethyl ketone or cyclohexanone from the viewpoints of drying rate and price.

[0050] As a method for applying the adhesive varnish to the support film, known methods can be used, such as knife coating method, roll coating method, spray coating method, gravure coating method, bar coating method, curtain coating method, and the like. The heat drying is not particularly limited as long as the solvent used is sufficiently volatilized, 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 for example, it may be 1 μm or more.

[0052] The film-like adhesive 1 is a film-like adhesive that may be in the following conditions in a cutting property evaluation method using the results of a cutting test (a cutting property evaluation method of the film-like adhesive under a low temperature condition where cooling expansion is carried out (for example, in the range of -15 °C to 0 °C)) where the cutting coefficient m is more than 0 and 70 or less, and the cutting resistance R is more than 0 N / mm 2 more than 40 N / mm 2 and the following. <Condition> Width of sample: 5 mm Length of sample: 23 mm Relative speed between the pressing jig and the sample: 10 mm / min

[0053] The following describes the cutting test. The cutting test is classified as a flexural strength test and includes a process of pushing the central part of the sample until the sample breaks while fixing both ends of the sample. As shown in Fig. 2, the sample S is subjected to the cutting test while being sandwiched and fixed by a pair of sample fixing jigs 14. The pair of sample fixing jigs 14 are made of, for example, cardboard having sufficient strength and each have a rectangular opening 14a at the center. A load is applied to the central part of the fixed sample S using a pushing jig 15 (see Fig. 3).

[0054] The sample S may be any one obtained by cutting out the film-like adhesive to be evaluated, and it is not necessary to produce a sample by laminating a plurality of adhesive pieces cut out from the film-like adhesive. That is, 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 Fig. 2) is, for example, 1 to 30 mm, and may be 3 to 8 mm. It may be set to an appropriate width according to the situation of the measuring device. The length of the sample S (Ls in Fig. 2) is, for example, 5 to 50 mm, and may be 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 the above as long as the cutting test can be carried out.

[0055] The pushing jig 15 is composed of a columnar member having a conical tip 15a. The diameter of the pushing jig 15 (R in Fig. 3) is, for example, 3 to 15 mm, and may be 5 to 10 mm. The angle of the tip 15a (θ in Fig. 3) is, for example, 40 to 120°, and may be 60 to 100°.

[0056] The cutting test is carried out in a thermostatic chamber set to a predetermined temperature. The thermostatic chamber may be set to a constant temperature in the range of -15°C to 0°C (the temperature of the assumed cooling expansion). As the thermostatic chamber, for example, TLF-R3-F-W-PL-S manufactured by ITEC Co., Ltd. can be used. An autograph (for example, AZT-CA01 manufactured by A&D Co., Ltd., load cell 50N, compression mode) is used to obtain the cutting work W, the cutting strength P, and the cutting 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 during the cutting process tends not to be fully obtained. If it is too slow, the stress relaxes and it tends to be 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 surrounded when a graph is created with the vertical axis being the load and the horizontal axis being the pressing amount 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 trigonometric functions 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 the cutting resistance R (N / mm 2 ) are obtained from Expression (1) and Expression (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 performed 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 40 N / mm or less. 2 The film-like adhesive having the following is likely to be excellent in the fragmentability 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 cutting coefficient m (dimensionless) may be greater than 0 and less than or equal to 70 as described above, and may be 10 to 60 or 15 to 55. The cutting coefficient m is a parameter related to the stretchability of the film adhesive under low-temperature conditions. When the cutting coefficient m exceeds 70, the film adhesive has excessive stretchability, and the cutability by cooling expansion tends to be insufficient. Note that when the cutting coefficient m is 15 or more, the stress propagation tends to be good. The cutting resistance R may be greater than 0 N / mm 2 and less than 40 N / mm 2 or may be greater than 0 N / mm 2 and less than 35 N / mm 2 or 1 to 30 N / mm 2 and may be used. When the cutting resistance R exceeds 40 N / mm 2 , the film adhesive has excessive strength, and the cutability by cooling expansion tends to be insufficient. Note that when the cutting resistance R is 20 N / mm 2 or more, better cutability by cooling expansion can be obtained by good stress propagation in cooling expansion. The film adhesive with the cutting coefficient m and the cutting resistance R within the above ranges can be suitably used for stealth dicing. The film adhesive with the cutting coefficient m and the cutting resistance R within the above ranges can be applied to the manufacturing process of semiconductor devices where cooling expansion is performed.

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

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

[0064] The cover film 3 is used to prevent damage or contamination of the film-like adhesive, and may be, for example, a polyethylene film, a polypropylene film, a film with a surface release agent treatment, etc. 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 base material 2 in the same manner as the method for forming the above-described film-like adhesive. The method of applying the adhesive composition to the base material 2 may be the same as the method of applying the above-described adhesive composition (adhesive varnish) to the support film.

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

[0067] The adhesive sheets 100 and 110 can be formed using a previously prepared film-like adhesive. In this case, the adhesive sheet 100 can be formed by laminating it on the base material 2 under predetermined conditions (for example, room temperature (20 °C) or in a heated state) using a roll laminator, a vacuum laminator, etc. Since the adhesive sheet 100 can be continuously manufactured and is excellent in efficiency, it may 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 base material 2 is a dicing tape. FIG. 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 FIG. 7 includes a dicing tape 8 and a film-like adhesive 1 provided on the dicing tape 8. When using the dicing-die bonding integrated adhesive sheet, the lamination process on the semiconductor wafer becomes one time, so that the work efficiency can be improved.

[0069] In one embodiment, the dicing tape 8 includes a base material film 7 and an adhesive layer 6 provided on the base material 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 coating, UV treatment, corona discharge treatment, polishing treatment, and etching treatment as necessary.

[0071] The adhesive layer 6 is not particularly limited as long as it has sufficient adhesive strength to prevent the semiconductor element from scattering during dicing and has a low adhesive strength that does not damage the semiconductor element during the subsequent pick-up process of the semiconductor element, and those conventionally known in the field of dicing tape can be used. The adhesive layer 6 may be either a pressure-sensitive type or a radiation-curable type.

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

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

[0074] The film-shaped adhesive and the bonding sheet may be those used in the manufacture of semiconductor devices. After laminating the film-shaped adhesive and the dicing tape on a semiconductor wafer or a semiconductor element (semiconductor chip) that has already been singulated at 0°C to 90°C, a semiconductor element with a film-shaped adhesive is obtained by cutting with a rotary blade, laser, or stretching, and then the semiconductor element with the film-shaped adhesive is used in the manufacture of a semiconductor device including a step of bonding it onto an organic substrate, a lead frame, or another semiconductor element.

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

[0076] The film-like adhesive and the adhesive sheet 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 resins and epoxy resins; materials obtained by impregnating and curing plastics such as polyimide resins and epoxy resins into base materials such as glass nonwoven fabrics; and semiconductor mounting support members such as ceramics such as alumina.

[0077] The film-like adhesive and the adhesive sheet are also preferably used as adhesives for bonding semiconductor elements to each other in a Stacked-PKG having a structure in which a plurality of semiconductor elements are stacked. In this case, one semiconductor element serves as a support member for mounting the semiconductor element.

[0078] The film-like adhesive and the adhesive sheet can also be used, for example, as a protective sheet for protecting the back surface of a semiconductor element of a flip-chip type semiconductor device, a sealing sheet for sealing between the front surface of a semiconductor element of a flip-chip type semiconductor device and an adherend, and the like.

[0079] The semiconductor device manufactured using the film-like adhesive will be specifically described below with reference to the drawings. In recent years, semiconductor devices with various structures have been proposed, and the applications of the film-like adhesive according to this embodiment are not limited to semiconductor devices with the structures described below.

[0080] FIG. 8 is a schematic cross-sectional view showing an embodiment of a semiconductor device. The semiconductor device 200 shown in FIG. 8 includes a semiconductor element 9, a support member 10 for mounting the semiconductor element 9, and an adhesive member (cured product 1c of the film-like adhesive) provided between the semiconductor element 9 and the support member 10 for bonding the semiconductor element 9 and the support member 10. The connection terminals (not shown) of the semiconductor element 9 are electrically connected to external connection terminals (not shown) via wires 11 and are sealed with a sealing material 12.

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

[0082] The semiconductor devices (semiconductor packages) shown in FIGS. 8 and 9 are obtained, for example, by interposing a film-like adhesive between the semiconductor element and the support member or between the semiconductor elements, heat-pressing them to adhere the two, and then, if necessary, through processes such as a wire bonding process, a sealing process with a sealing material, and a heat melting process including reflow by solder. The heating temperature in the heat-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 of interposing a film-like adhesive between the semiconductor element and the support member or between the semiconductor elements, as described above, it may be a method of producing a semiconductor element with a film-like adhesive in advance and then attaching it to the support member or the semiconductor element.

[0084] Next, an embodiment of a method for manufacturing a semiconductor device when using the dicing / die bonding integrated adhesive sheet shown in FIG. 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 for manufacturing a semiconductor device described below.

[0085] First, a semiconductor wafer is pressed against the film-like adhesive 1 in the adhesive sheet 120 (dicing / die-bonding integrated adhesive sheet), and this is adhered, held, and fixed (mounting process). This process may be performed while pressing by pressing means such as a pressing roll.

[0086] Next, dicing of the semiconductor wafer is performed. By this, the semiconductor wafer is cut into a predetermined size to manufacture a plurality of individual semiconductor elements (semiconductor chips) with film-like adhesives. Dicing can be performed, for example, from the circuit surface side of the semiconductor wafer according to a conventional method. Also, in this process, for example, a cutting method called a full cut in which a cut is made up to the dicing tape, a method of cutting the semiconductor wafer halfway and then pulling it while cooling to divide it, a cutting method using a laser, etc. can be adopted. The dicing device used in this process is not particularly limited, and a conventionally known one can be used.

[0087] In order to peel the semiconductor element adhered and fixed to the dicing / die-bonding integrated adhesive sheet, pickup of the semiconductor element is performed. The method of pickup is not particularly limited, and various conventionally known methods can be adopted. For example, a method of pushing up each semiconductor element from the dicing / die-bonding integrated adhesive sheet side with a needle and picking up the pushed-up semiconductor element with a pickup device, etc. can be mentioned.

[0088] Here, when the adhesive layer is a radiation (e.g., ultraviolet ray) curable type, pickup is performed after irradiating the adhesive layer with radiation. Thereby, the adhesive force of the film-like adhesive of the adhesive layer decreases, and the peeling of the semiconductor element becomes easy. As a result, pickup becomes possible without damaging the semiconductor element.

[0089] Next, the semiconductor element with the film-like adhesive formed by dicing is adhered to a support member for mounting the semiconductor element via the film-like adhesive. The adhesion may be performed by pressure bonding. The conditions for die bonding are not particularly limited and can be set as appropriate according to requirements. 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 thermally curing the film-like adhesive may be provided. By thermally curing the film-like adhesive that adheres the support member and the semiconductor element in the above adhesion step, stronger adhesion and fixation become possible. When performing thermal curing, pressure may be applied simultaneously for curing. The heating temperature in this step can be appropriately changed depending on the constituent 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 step by step.

[0091] Next, a wire bonding step is performed to electrically connect the tip of the terminal portion (inner lead) of the support member and the electrode pad on the semiconductor element with a bonding wire. As the bonding wire, for example, a gold wire, an aluminum wire, a copper wire, etc. are used. The temperature when performing wire bonding may be within the range of 80 to 250°C or 80 to 220°C. The heating time may be several seconds to several minutes. The connection may be performed by the combined use of vibration energy by ultrasonic waves and pressure bonding energy by applied pressure while being heated within the above temperature range.

[0092] Next, a sealing step of sealing the semiconductor element with a sealing resin is performed. This step is performed to protect the semiconductor element or the bonding wire mounted on the support member. This step is performed by molding the resin for sealing with a mold. As the sealing resin, for example, an epoxy-based resin may be used. The substrate and residues are embedded by the heat and pressure during sealing, and peeling due to air bubbles at the adhesion interface can be prevented.

[0093] Next, in the post-curing process, the encapsulation resin that was insufficiently cured in the encapsulation process is completely cured. Even if the film adhesive is not thermally cured in the encapsulation process, in this process, the film adhesive can be thermally cured and adhesively fixed along with the curing of the encapsulation resin. The heating temperature in this process can be appropriately set according to the type of encapsulation 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 the film adhesive adhered to the support member is heated using a reflow furnace. In this process, the resin-encapsulated semiconductor device may be surface-mounted on the support member. Examples of the surface-mounting method include, for example, reflow soldering in which solder is previously supplied on a printed wiring board and then heated and melted by warm air or the like for soldering. Examples of the heating method include hot air reflow, infrared reflow, etc. Also, the heating method may be one that heats the whole or one that heats a part. The heating temperature may be, for example, in the range of 240 to 280°C.

Example

[0095] Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited thereto.

[0096] [Production of Film Adhesive] (Examples 1 to 6 and Comparative Example 1) [Preparation of Adhesive Varnish] Cyclohexanone was added to the composition composed of component (A), component (B), and component (D) with the components and contents (unit: parts by mass) shown in Table 1, and stirred and mixed. Component (C) ((component (C1) or component (C2))) was added thereto and stirred, and then component (E) and component (F) were added, and stirred until each component became uniform to prepare an adhesive varnish. Note that the numerical values of component (C) shown in Table 1 mean parts by mass of the solid content.

[0097] Note that each component shown in Table 1 means the following.

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

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

[0100] (C) Component: Elastomer (C1) Component: Elastomer satisfying condition (i) and condition (ii) (C1-1) Acrylic rubber solution (in the acrylic rubber in SG-P3 (trade name, manufactured by Nagase ChemteX Corporation, methyl ethyl ketone solution of acrylic rubber), a solution of acrylic rubber with a part of the constituent units of the acrylic rubber changed, measured Tg of acrylic rubber: 20 °C, weight average molecular weight of acrylic rubber: 800,000) (C1-2) Acrylic rubber solution (in the acrylic rubber in SG-P3 (trade name, manufactured by Nagase ChemteX Corporation, methyl ethyl ketone solution of acrylic rubber), a solution of acrylic rubber with a part of the constituent units of the acrylic rubber changed, measured Tg of acrylic rubber: 25 °C, weight average molecular weight of acrylic rubber: 800,000) (C1-3) Acrylic rubber solution (in the acrylic rubber in SG-P3 (trade name, manufactured by Nagase ChemteX Corporation, methyl ethyl ketone solution of acrylic rubber), a solution of acrylic rubber with a part of the constituent units of the acrylic rubber changed, measured Tg of acrylic rubber: 12 °C, weight average molecular weight of acrylic rubber: 500,000) (C1-4) Acrylic rubber solution (in the acrylic rubber in SG-P3 (trade name, manufactured by Nagase ChemteX Corporation, methyl ethyl ketone solution of acrylic rubber), a solution of acrylic rubber with a part of the constituent units of the acrylic rubber changed, measured Tg of acrylic rubber: 20 °C, weight average molecular weight of acrylic rubber: 500,000) (C1-5) In the acrylic rubber in the acrylic rubber solution (SG-P3 (trade name, manufactured by Nagase ChemteX Corporation, methyl ethyl ketone solution of acrylic rubber)), a solution of acrylic rubber in which a part of the constituent units of the acrylic rubber is changed, measured Tg of acrylic rubber: 20 °C, weight average molecular weight of acrylic rubber: 200,000 (C2) Component: Elastomer other than component (C1) (C2-1) In the acrylic rubber in the acrylic rubber solution (SG-P3 (trade name, manufactured by Nagase ChemteX Corporation, methyl ethyl ketone solution of acrylic rubber)), a solution of acrylic rubber in which a part of the constituent units of the acrylic rubber is changed, measured Tg of acrylic rubber: 3 °C, weight average molecular weight of acrylic rubber: 800,000

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

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

[0103] (F) Component: Curing accelerator (F-1) 2PZ-CN (trade name, manufactured by Shikoku Kasei Kogyo Co., Ltd., 1-cyanoethyl-2-phenylimidazole)

[0104] <Preparation of film-like adhesive> The prepared adhesive varnish was filtered through a 100-mesh filter and degassed under vacuum. As the base material, a polyethylene terephthalate (PET) film with a thickness of 38 μm and subjected to a release treatment was prepared, and the adhesive varnish after vacuum degassing was applied onto the PET film. The applied adhesive varnish was heat-dried in two steps at 90°C for 5 minutes and then at 130°C for 5 minutes to obtain the film-shaped adhesives of Examples 1 to 3 and Comparative Example 1 in the B-stage state. In the film-shaped adhesives, the thickness of the film-shaped adhesives was adjusted to 10 μm depending on the coating amount of the adhesive varnish.

[0105] <Evaluation of the Dissectibility of the Film-shaped Adhesive by Cooling Expansion> Adhesive pieces (width 5 mm × length 100 mm) were cut out from the film-shaped adhesives of Examples 1 to 6 and Comparative Example 1, respectively. The adhesive pieces were fixed to a pair of jigs (cardboard), and the portions of the adhesive pieces protruding from the jigs were removed. Thereby, a sample to be evaluated (width 5 mm × length 23 mm) was obtained. A cutting test was carried out in a thermostatic chamber (manufactured by ITEC Corporation, TLF-R3-F-W-PL-S) set to a predetermined temperature condition. That is, using an autograph (manufactured by A&D Company, Limited, AZT-CA01, load cell 50 N), a cutting test was carried out under the conditions of a compression mode, a speed of 10 mm / min, and a pushing distance of 5 mm, and the cutting work W, cutting strength P, and cutting elongation L when the film-shaped adhesive broke were determined. The cutting coefficient m and cutting resistance R were calculated by the above formulas (1) and (2). In addition, the cutting test was carried out 8 times or more for each example and each comparative example. The results are shown in Table 1. The values described in Table 1 are the average values of the results obtained by a plurality of cutting tests.

[0106] To confirm that the dissectibility evaluation matches the dissectibility in cooling expansion, dicing / die bonding integrated films each comprising the film-shaped adhesives of Examples 1 to 6 and Comparative Example 1 as the adhesive layer were produced, and the dissectibility of the adhesive layer (film-shaped adhesive) was evaluated under the following conditions. · Thickness of the silicon wafer: 30 μm · Chip size to be individualized by stealth dicing: length 10 mm × width 10 mm · Temperature of cooling expansion: The same temperature as the constant temperature bath for the cleavage test of the examples and comparative examples · Pushing up by the expansion ring: 10 mm · Evaluation criteria: Light was irradiated on the silicon wafer after pushing up by the expansion ring. Those through which light passed between adjacent adhesive-attached chips (where the silicon wafer and the adhesive layer were separated) were evaluated as "A", and those with an area where light did not pass (where the silicon wafer and the adhesive layer were not separated) were evaluated as "B". The results are shown in Table 1.

[0107]

Table 1

[0108] As shown in Table 1, the film adhesives of Examples 1 to 6 had a cleavage coefficient m of 70 or less and a cleavage resistance R of 40 N / mm 2 or less, and the evaluation of the cleavage property by cooling expansion was "A". On the other hand, the film adhesive of Comparative Example 1 had a cleavage coefficient m exceeding 70 and a cleavage resistance R exceeding 40 N / mm 2 and the evaluation of the cleavage property by cooling expansion was "B". From these results, it was confirmed that the film adhesive of the present invention was excellent in the cleavage property by cooling expansion.

Explanation of symbols

[0109] 1... Film 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... Fixture for sample fixing, 14a... Opening, 15... Pushing-in jig, 15a... Tip, 100, 110, 120... Adhesive sheet, 200, 210... Semiconductor device, S... Sample.

Claims

1. A film adhesive for bonding a semiconductor element and a support member on which the semiconductor element is mounted, wherein the film adhesive contains a thermosetting resin, a curing agent, and an elastomer, and the elastomer includes an elastomer satisfying the following condition (i) and the following condition (ii). A film adhesive. Condition (i): The glass transition temperature is 12°C or higher. Condition (ii): The weight average molecular weight is 800,000 or less.

2. A step of preparing a sample having a cross-sectional area A (mm ２ ) from the film adhesive; A step of obtaining the cutting work 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°C to 0°C, a step of obtaining a cutting coefficient m represented by the following formula (1), Step of obtaining the cutting resistance R (N / mm represented by the following formula (2) ２ ), and In the method for evaluating the segmentability, which includes [conditions not specified in the original] and is carried out under the following conditions, the segment coefficient m is greater than 0 and less than or equal to 70, and the segment resistance R is greater than 0 N / mm ２ and less than 40 N / mm ２ The film adhesive according to claim 1, wherein [conditions not specified in the original]. m = W / [1000×(P×L)] (1) R = P / A (2) <Condition> Width of the sample: 5 mm Length of the sample: 23 mm Relative speed between the pressing jig and the sample: 10 mm / min

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

4. A base material, the film adhesive according to any one of claims 1 to 3 provided on one surface of the base material, and an adhesive sheet comprising the same.

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

6. A semiconductor element, a support member on which the semiconductor element is mounted, an adhesive member provided between the semiconductor element and the support member for bonding the semiconductor element and the support member, comprising, a semiconductor device, wherein the adhesive member is a cured product of the film adhesive according to any one of claims 1 to 3.

7. A method for manufacturing a semiconductor device, comprising a step of bonding a semiconductor element and a support member using the film adhesive according to any one of claims 1 to 3.

8. A step of attaching the film adhesive of the adhesive sheet according to claim 4 or 5 to a semiconductor wafer, a step of producing a plurality of singulated semiconductor elements with the film adhesive by cutting the semiconductor wafer to which the film adhesive is attached, and a step of bonding the semiconductor element with the film adhesive to a support member. A method for manufacturing a semiconductor device, comprising the same.

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