JPWO2019167460A1 - Adhesives for semiconductors and methods for manufacturing semiconductor devices using them - Google Patents

Abstract

In a semiconductor device in which the electrodes of the connection portions of the semiconductor chip and the wiring circuit board are electrically connected to each other, or in a semiconductor device in which the electrodes of the connection portions of a plurality of semiconductor chips are electrically connected to each other. , A semiconductor adhesive used for encapsulating at least a part of a connection portion, wherein the semiconductor adhesive has a thixotropy value of 1.0 or more and 3.1 or less, and the thixotropy value is a semiconductor adhesive. The viscosity of a sample laminated to a thickness of 400 μm was measured with a shear viscosity measuring device when the frequency was continuously changed from 1 Hz to 70 Hz under constant conditions of a temperature of 120 ° C., and the viscosity value at 7 Hz was set to 70 Hz. Adhesive for semiconductors, which is the value divided by the viscosity value of.

Description

The present disclosure relates to an adhesive for semiconductors and a method for manufacturing a semiconductor device using the adhesive.

Conventionally, a wire bonding method using a fine metal wire such as a gold wire has been widely applied to connect a semiconductor chip and a substrate. On the other hand, in order to meet the demands for high functionality, high integration, high speed, etc. for semiconductor devices, a flip chip in which conductive protrusions called bumps are formed on the semiconductor chip or substrate and directly connected between the semiconductor chip and the substrate. The connection method (FC connection method) is becoming widespread.

Flip-chip connection methods include a method of metal bonding using solder, tin, gold, silver, copper, etc., a method of applying ultrasonic vibration to metal bonding, a method of maintaining mechanical contact by the shrinkage force of resin, etc. However, from the viewpoint of reliability of the connecting portion, a method of metal bonding using solder, tin, gold, silver, copper or the like is common.

For example, in the connection between a semiconductor chip and a substrate, a COB (Chip On Board) type connection method, which is widely used in BGA (Ball Grid Array), CSP (Chip Size Package), etc., is also a flip chip connection method. .. The flip-chip connection method is also widely used in a COC (Chip On Chip) type connection method in which a connection portion (bump or wiring) is formed on a semiconductor chip and the semiconductor chips are connected to each other (for example,). See Patent Document 1 below).

Chip stack type packages, POP (Package On Package), TSV (Through-Silicon Via), etc., in which the above-mentioned connection methods are stacked and multi-staged, are widely used in packages that are strongly required to be further miniaturized, thinned, and highly functional. It is beginning to spread. Since the package can be made smaller by arranging it in a three-dimensional shape instead of a flat shape, these technologies are widely used, and are effective for improving semiconductor performance, reducing noise, reducing mounting area, and saving power, and are effective for next-generation semiconductors. It is attracting attention as a wiring technology.

Japanese Unexamined Patent Publication No. 2016-102165

In flip-chip packages, which are becoming more sophisticated, highly integrated, and cost-effective, it is required to suppress the resin protrusion width when the chip is mounted and to mount the chip at a high density for high productivity. Therefore, if the crimping load is lightened, the resin protrusion width is suppressed, but there is a concern that the corners of the chip will be short of resin, leading to chip peeling and the like.

In the present disclosure, a semiconductor adhesive and a semiconductor using the same can be obtained by controlling the shape of the resin that protrudes when the chip is mounted and by causing the resin to protrude along the side surface of the chip so that a semiconductor device without resin shortage can be obtained at the time of mounting. The main purpose is to provide a method for manufacturing the device.

One aspect of the present disclosure is that [1] a semiconductor device in which the electrodes of the connection portions of the semiconductor chip and the wiring circuit board are electrically connected to each other, or the electrodes of the connection portions of a plurality of semiconductor chips are connected to each other. In semiconductor devices electrically connected to each other, a semiconductor adhesive used for sealing at least a part of the connection portion, and the thixotropy value of the semiconductor adhesive is 1.0 or more and 3.1. The above thixotropy value is obtained when the frequency of a sample in which the above semiconductor adhesive is laminated to a thickness of 400 μm is continuously changed from 1 Hz to 70 Hz under a constant condition of a temperature of 120 ° C. by a shear viscosity measuring device. Is a semiconductor adhesive, which is a value obtained by measuring the viscosity of the semiconductor and dividing the viscosity value at 7 Hz by the viscosity value at 70 Hz.

The other aspect of the present disclosure is described in the above [1], which contains [2] (a) an epoxy resin, (b) a curing agent, and (c) a high molecular weight component having a weight average molecular weight of 10,000 or more. It is an adhesive for semiconductors.

Further, another aspect of the present disclosure is the semiconductor adhesive according to the above [2], which further contains [3] and (d) a filler.

Further, another aspect of the present disclosure is the semiconductor adhesive according to the above [2] or [3], which further contains [4] and (e) a flux agent.

In addition, another aspect of the present disclosure is any of the above [2] to [4], wherein the polydispersity Mw / Mn of the high molecular weight component having a weight average molecular weight of 10,000 or more is 3 or less. The semiconductor adhesive according to the above.

Further, another aspect of the present disclosure is described in any one of the above [2] to [5], wherein a part or all of the material contained in the above-mentioned semiconductor adhesive is soluble in cyclohexanone. Adhesive for semiconductors.

Further, another aspect of the present disclosure is the semiconductor adhesive according to any one of the above [1] to [6], which is in the form of a film [7].

Further, another aspect of the present disclosure is to use the semiconductor adhesive according to any one of [8] above [1] to [7], and to use a connecting device via the semiconductor adhesive to make a semiconductor chip and a wiring circuit. Align the substrates, connect them to each other, electrically connect the electrodes of the respective connection portions of the semiconductor chip and the wiring circuit substrate to each other, and seal at least a part of the connection portions with the semiconductor adhesive. A process or a connecting device aligns a plurality of semiconductor chips via the semiconductor adhesive, connects the semiconductor chips to each other, and electrically connects the electrodes of the connecting portions of the plurality of semiconductor chips to each other. This is a method for manufacturing a semiconductor device, comprising a step of sealing at least a part of a connecting portion with the above-mentioned semiconductor adhesive.

According to the present disclosure, by controlling the thixotropy value of the semiconductor adhesive, the shape of the resin protruding to the outer periphery of the chip at the time of mounting the semiconductor device is controlled, and the resin protrudes along the side surface of the chip to prevent the resin shortage. It can be suppressed. Further, according to the present disclosure, it is possible to provide a semiconductor device using such an adhesive for semiconductors and a method for manufacturing the same.

It is a schematic cross-sectional view which shows one Embodiment of the semiconductor device which concerns on this disclosure. It is a schematic cross-sectional view which shows the other embodiment of the semiconductor device which concerns on this disclosure. It is a schematic cross-sectional view which shows the other embodiment of the semiconductor device which concerns on this disclosure. It is a schematic cross-sectional view which shows the other embodiment of the semiconductor device which concerns on this disclosure.

Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the drawings in some cases. In the drawings, the same or corresponding parts are designated by the same reference numerals, and duplicate description will be omitted. Further, unless otherwise specified, the positional relationship such as up, down, left, and right shall be based on the positional relationship shown in the drawings. Furthermore, the dimensional ratios in the drawings are not limited to the ratios shown.

In the present specification, the numerical range indicated by using "~" indicates a range including the numerical values before and after "~" as the minimum value and the maximum value, respectively. In the numerical range described stepwise in the present specification, the upper limit value or the lower limit value of the numerical range of one step can be arbitrarily combined with the upper limit value or the lower limit value of the numerical range of another step. In the numerical range described in the present specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. “A or B” may include either A or B, or both. Unless otherwise specified, the materials shown in the examples of the present specification may be used alone or in combination of two or more. As used herein, the term "(meth) acrylic" means acrylic or the corresponding methacrylic.

<Adhesive for semiconductors>
The semiconductor adhesive according to the present embodiment is a semiconductor device in which the electrodes of the connection portions of the semiconductor chip and the wiring circuit board are electrically connected to each other, or the electrodes of the connection portions of a plurality of semiconductor chips. Are used to seal at least a portion of the connection in semiconductor devices that are electrically connected to each other.

The semiconductor adhesive according to this embodiment has a thixotropy value of 1.0 or more and 3.1 or less. The thixotropy value is measured by measuring the viscosity of a sample in which the above-mentioned semiconductor adhesive is laminated to a thickness of 400 μm when the frequency is continuously changed from 1 Hz to 70 Hz under a constant temperature of 120 ° C. with a shear viscosity measuring device. , The value obtained by dividing the viscosity value at 7 Hz by the viscosity value at 70 Hz. When the thixotropy value is 3.1 or less, the semiconductor adhesive can sufficiently flow even at the corner of the chip where the shear applied at the time of chip mounting is the smallest, and the resin protrudes in a shape along the side surface of the chip. It will be. The thixotropy value may be 1.5 or more, 2.0 or more, or 2.5 or more.

The semiconductor adhesive according to the present embodiment may contain (a) an epoxy resin, (b) a curing agent, (c) a high molecular weight component having a weight average molecular weight of 10,000 or more, and (d) a filler, (e). ) It is preferable to contain a flux agent.

((A) component: epoxy resin)
Examples of the component (a) component epoxy resin include epoxy resins having two or more epoxy groups in the molecule, such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, naphthalene type epoxy resin, and phenol novolac type epoxy resin. Cresol novolac type epoxy resin, phenol aralkyl type epoxy resin, biphenyl type epoxy resin, triphenylmethane type epoxy resin, dicyclopentadiene type epoxy resin, various polyfunctional epoxy resins and the like can be used. The component (a) can be used alone or in combination of two or more.

The content of the component (a) is preferably 10 to 50% by mass, more preferably 15 to 45% by mass, and further preferably 20 to 40% by mass based on the total solid content of the semiconductor adhesive. is there. When the content of the component (a) is 10% by mass or more, it is easy to sufficiently control the flow of the resin after curing, and when it is 50% by mass or less, the resin component of the cured product does not become too large and the package Easy to reduce warpage. Further, by setting the content of the component (a) within the above range, it is easy to control the thixotropy value of the semiconductor adhesive to 1.0 or more and 3.1 or less. Since the thixotropy value tends to be smaller when the resin component is small and the filler content is high, the thixotropy value can be easily lowered by setting the content of the component (a) to 50% by mass or less.

((B) component: curing agent)
The semiconductor adhesive according to this embodiment contains (b) a curing agent. Examples of the curing agent include a phenol resin-based curing agent, an acid anhydride-based curing agent, an amine-based curing agent, an imidazole-based curing agent, and a phosphine-based curing agent. (B) When the component contains a phenolic hydroxyl group, an acid anhydride, amines or imidazoles, it is easy to show a flux activity that suppresses the formation of an oxide film at the connection portion, and the connection reliability and insulation reliability are easily improved. Can be made to. Hereinafter, each curing agent will be described.

(Bi) Phenol resin-based curing agent Examples of the phenol resin-based curing agent include a curing agent having two or more phenolic hydroxyl groups in the molecule, such as phenol novolac resin, cresol novolac resin, phenol aralkyl resin, and cresol naphthol. Formaldehyde polycondensate, triphenylmethane type polyfunctional phenol resin, various polyfunctional phenol resins and the like can be used. The phenol resin-based curing agent can be used alone or in combination of two or more.

The equivalent ratio (phenolic hydroxyl group / epoxy group, molar ratio) of the phenol resin-based curing agent to the component (a) is preferably 0.3 to 1.5 from the viewpoint of excellent curability, adhesiveness and storage stability. , 0.4 to 1.0 is more preferable, and 0.5 to 1.0 is even more preferable. When the equivalent ratio is 0.3 or more, the curability tends to be improved and the adhesive strength tends to be improved, and when it is 1.5 or less, unreacted phenolic hydroxyl groups do not remain excessively and the water absorption rate. Is kept low, and the insulation reliability tends to be further improved.

(B-ii) Acid anhydride-based curing agent Examples of the acid anhydride-based curing agent include methylcyclohexanetetracarboxylic dianhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic dianhydride, and ethylene glycol bis. Anhydrotrimellitic or the like can be used. The acid anhydride-based curing agent may be used alone or in combination of two or more.

The equivalent ratio (acid anhydride group / epoxy group, molar ratio) of the acid anhydride-based curing agent to the component (a) is 0.3 to 1.5 from the viewpoint of excellent curability, adhesiveness and storage stability. Is preferable, 0.4 to 1.0 is more preferable, and 0.5 to 1.0 is further preferable. When the equivalent ratio is 0.3 or more, the curability tends to be improved and the adhesive strength tends to be improved, and when it is 1.5 or less, unreacted acid anhydride does not remain excessively and the water absorption rate. Is kept low, and the insulation reliability tends to be further improved.

(B-iii) Amine-based curing agent As the amine-based curing agent, dicyandiamide, various amine compounds and the like can be used.

The equivalent ratio (amine / epoxy group, molar ratio) of the amine-based curing agent to the component (a) is preferably 0.3 to 1.5 from the viewpoint of excellent curability, adhesiveness and storage stability, and is preferably 0.4. ~ 1.0 is more preferable, and 0.5 to 1.0 is even more preferable. When the equivalent ratio is 0.3 or more, the curability tends to be improved and the adhesive strength tends to be improved, and when it is 1.5 or less, unreacted amine does not remain excessively and the insulation reliability is improved. It tends to improve further.

(B-iv) Imidazole-based curing agent Examples of the imidazole-based curing agent include 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-. Cyanoethyl-2-undecylimidazole, 1-cyano-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimerite, 1-cyanoethyl-2-phenylimidazolium trimerite, 2,4-diamino-6 -[2'-methylimidazolyl- (1')]-ethyl-s-triazine, 2,4-diamino-6- [2'-undecylimidazolyl- (1')]-ethyl-s-triazine, 2, 4-Diamino-6- [2'-ethyl-4'-methylimidazolyl- (1')] -ethyl-s-triazine, 2,4-diamino-6- [2'-methylimidazolyl- (1')] -Ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, epoxy resin and imidazole Examples include adducts of the type. Among these, 1-cyanoethyl-2-undecylimidazole, 1-cyano-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimeri are further excellent in curability, storage stability and connection reliability. Tate, 1-cyanoethyl-2-phenylimidazolium trimerite, 2,4-diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s-triazine, 2,4-diamino-6- [2'-Ethyl-4'-methylimidazolyl- (1')]-ethyl-s-triazine, 2,4-diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s-triazine Isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole and 2-phenyl-4-methyl-5-hydroxymethylimidazole are preferred. The imidazole-based curing agent may be used alone or in combination of two or more. Further, these may be used as a microencapsulated latent curing agent.

The content of the imidazole-based curing agent is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the component (a). When the content of the imidazole-based curing agent is 0.1 parts by mass or more, the curability tends to be improved, and when it is 20 parts by mass or less, the adhesive composition is cured before the metal bond is formed. There is no tendency for poor connection to occur.

(Vv) Phosphine-based curing agent Examples of the phosphine-based curing agent include triphenylphosphine, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra (4-methylphenyl) borate, and tetraphenylphosphonium (4-fluorophenyl) borate. Can be mentioned.

The content of the phosphine-based curing agent is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the component (a). When the content of the phosphine-based curing agent is 0.1 parts by mass or more, the curability tends to be improved, and when it is 10 parts by mass or less, the semiconductor adhesive is cured before the metal bond is formed. There is no tendency for poor connection to occur.

The phenol resin-based curing agent, the acid anhydride-based curing agent, and the amine-based curing agent can be used alone or in combination of two or more. The imidazole-based curing agent and the phosphine-based curing agent may be used alone, or may be used together with a phenol resin-based curing agent, an acid anhydride-based curing agent, or an amine-based curing agent.

As the component (b), from the viewpoint of excellent curability, a phenol resin-based curing agent and an imidazole-based curing agent are used in combination, an acid anhydride-based curing agent and an imidazole-based curing agent are used in combination, and an amine-based curing agent and an imidazole-based curing agent are used in combination. It is preferable to use the imidazole-based curing agent alone. Since the productivity is improved when the connection is made in a short time, it is more preferable to use the imidazole-based curing agent having excellent quick curing property alone. In this case, since the volatile components such as low molecular weight components can be suppressed by curing in a short time, the generation of voids can be easily suppressed.

(Component (c): High molecular weight component having a weight average molecular weight of 10,000 or more)
Examples of the high molecular weight component (excluding the compound corresponding to the component (a)) having a weight average molecular weight of 10,000 or more include phenoxy resin, polyimide resin, polyamide resin, polycarbodiimide resin, cyanate ester resin, and (meth) acrylic resin. Examples thereof include polyester resin, polyethylene resin, polyether sulfone resin, polyetherimide resin, polyvinyl acetal resin, polyurethane resin, acrylic rubber, etc. Among them, phenoxy resin, polyimide resin, etc. from the viewpoint of excellent heat resistance and film forming property. (Meta) acrylic resin, acrylic rubber, cyanate ester resin, and polycarbodiimide resin are preferable, and phenoxy resin, polyimide resin, (meth) acrylic resin, and acrylic rubber are more preferable. The component (c) can also be used alone or as a mixture of two or more kinds or a copolymer.

The mass ratio of the component (c) to the component (a) is not particularly limited, but in order to maintain the film shape, the content of the component (a) is 0 with respect to 1 part by mass of the component (c). It is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 4 parts by mass, and further preferably 0.1 to 3 parts by mass. When the content of the component (a) is 0.01 parts by mass or more, the curability does not decrease or the adhesive strength does not decrease, and when the content is 5 parts by mass or less, the film formability and the film are formed. The formability does not decrease. The thixotropy value can also be adjusted by the combination of the component (c) and the component (a) and their mass ratios.

The weight average molecular weight of the component (c) is 10,000 or more in terms of polystyrene, but it is preferably 30,000 or more, more preferably 40,000 or more, still more preferably 50,000 or more, in order to exhibit good film forming property by itself. When the weight average molecular weight is 10,000 or more, there is no possibility that the film formability is deteriorated. In addition, in this specification, the weight average molecular weight means the weight average molecular weight when measured in polystyrene conversion using high performance liquid chromatography (C-R4A manufactured by Shimadzu Corporation).

The degree of polydispersity Mw / Mn of the component (c) is preferably 3 or less, and more preferably 2.5 or less. When Mw / Mn is 3 or less, it is considered that the variation in molecular weight is small and the thixotropy value tends to be low.

((D) component: filler)
Examples of the filler of the component (d) include an insulating inorganic filler and the like. Above all, an inorganic filler having an average particle size of 100 nm or less is more preferable. Examples of the insulating inorganic filler include glass, silica, alumina, titanium oxide, mica, and boron nitride. Among them, silica, alumina, titanium oxide, and boron nitride are preferable, and silica, alumina, and boron nitride are more preferable. The insulating inorganic filler may be a whisker, and examples of the whisker include aluminum borate, aluminum titanate, zinc oxide, calcium silicate, magnesium sulfate, and boron nitride. The insulating inorganic filler may be used alone or in combination of two or more. (D) The shape, particle size, and content of the component are not particularly limited.

From the viewpoint of further excellent insulation reliability, the component (d) is preferably insulating. The semiconductor adhesive according to this embodiment preferably does not contain a conductive metal filler such as a silver filler or a solder filler.

The component (d) is preferably a surface-treated filler from the viewpoint of improving dispersibility and adhesive strength. Examples of the surface treatment agent include glycidyl-based (epoxy-based) compounds (excluding compounds corresponding to component (a)), amine-based compounds, phenyl-based compounds, phenylamino-based compounds, and (meth) acrylic-based compounds (for example, the following general). Examples thereof include a compound having a structure represented by the formula (1)), a vinyl compound having a structure represented by the following general formula (2), and the like.

［Ｒ^１１は、水素原子又はアルキル基を示し、Ｒ^１２は、アルキレン基を示す。］

[R ¹¹ represents a hydrogen atom or an alkyl group, and R ¹² represents an alkylene group. ]

Examples of the filler surface-treated with the compound having the structure represented by the general formula (1) include an acrylic surface-treated filler in which ^{R 11} is a hydrogen atom, a methacrylic surface-treated filler in which ^{R 11 is a methyl group, and R 11} is ethyl. include ethacrylic surface treatment filler such as a group, the reactivity of the resin and the semiconductor substrate of the surface contained in the semiconductor adhesive, as well as in terms of bond formation, R ¹¹ is not bulky, acrylic surface treatment filler, methacrylic Surface-treated fillers are preferred. R ^{12 is} also not particularly limited, but a higher weight average molecular weight is preferable because it has less volatile components.

［Ｒ^２１、Ｒ^２２及びＲ^２３は、１価の有機基を示し、Ｒ^２４は、アルキレン基を示す。］

[R ²¹ , R ²² and R ²³ represent a monovalent organic group and R ²⁴ represents an alkylene group. ]

For example, from the viewpoint of not reducing the reactivity, R ²¹ , R ²² and R ²³ are preferably groups that are not relatively bulky, and may be, for example, a hydrogen atom or an alkyl group. Further, R ²¹ , R ²² and R ²³ may be monovalent organic groups in which the reactivity of the vinyl group is improved. R ^{24 is} also not particularly limited, but it is preferable that the weight average molecular weight is high from the viewpoint that voids can be easily reduced because it is hard to volatilize. Further, R ²¹ , R ²² , R ²³ and R ²⁴ may be selected depending on the ease of surface treatment.

As the surface treatment agent, a silane treatment agent such as an epoxy-based silane, an amino-based silane, or a (meth) acrylic-based silane is preferable because of the ease of surface treatment. As the surface treatment agent, glycidyl-based, phenylamino-based, and (meth) acrylic-based compounds are preferable from the viewpoint of excellent dispersibility, fluidity, and adhesive strength. As the surface treatment agent, phenyl-based and (meth) acrylic-based compounds are more preferable from the viewpoint of excellent storage stability.

The average particle size of the component (d) is preferably 100 nm or less, more preferably 60 nm or less, from the viewpoint of improving visibility. The component (d) is preferably an inorganic filler having an average particle size of 60 nm or less surface-treated with (meth) acrylic silane or epoxy-based silane from the viewpoint of improving adhesive strength. On the other hand, the thixotropy value tends to be smaller as the average particle size of the component (d) is larger.

The content of the component (d) is preferably 20 to 80% by mass, more preferably 30 to 75% by mass, and even more preferably 50 to 75% by mass, based on the total amount of the semiconductor adhesive. When the content of the component (d) is 20% by mass or more, there is no possibility that the adhesive strength is lowered or the reflow resistance is lowered. Further, when the content of the component (d) is 40% by mass or less, there is no possibility that the connection reliability is lowered due to the thickening. (D) The thixotropy value tends to be smaller as the content of the component is larger.

((E) component: flux agent)
The semiconductor adhesive can further contain (e) a flux agent that exhibits flux activity (activity to remove oxides, impurities, etc.). Examples of the flux agent include nitrogen-containing compounds having an unshared electron pair (imidazoles, amines, etc., excluding those contained in the component (b)), carboxylic acids, phenols and alcohols. In addition, carboxylic acids express more flux activity than alcohols, and it is easy to improve connectivity.

From the viewpoint of solder wettability, the content of the component (e) is preferably 0.2 to 3% by mass, preferably 0.4 to 1.8% by mass, based on the total solid content of the semiconductor adhesive. Is more preferable.

The semiconductor adhesive may further contain an ion trapper, an antioxidant, a silane coupling agent, a titanium coupling agent, a leveling agent, or the like. These may be used individually by 1 type, and may be used in combination of 2 or more type. The blending amount of these may be appropriately adjusted so that the effect of each additive is exhibited.

<Manufacturing method of adhesive for semiconductors>
The semiconductor adhesive according to the present embodiment is preferably in the form of a film (film-like adhesive) from the viewpoint of improving productivity. The method for producing the film-like adhesive will be described below.

First, a resin varnish is prepared by adding the component (a), the component (b), the component (c), and if necessary, other components into an organic solvent, and then dissolving or dispersing them by stirring, mixing, kneading, or the like. .. Then, a resin varnish is applied to the release-treated base film using a knife coater, a roll coater, an applicator, a die coater, a comma coater, or the like, and then the organic solvent is reduced by heating to reduce the organic solvent to the base film. A film-like adhesive is formed on top. Further, a film-like adhesive may be formed on the wafer by a method in which a resin varnish is spin-coated on a wafer or the like to form a film and then the solvent is dried before the organic solvent is reduced by heating.

The organic solvent used for preparing the resin varnish is preferably one having the property of uniformly dissolving or dispersing each component, and for example, dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, diethylene glycol dimethyl ether, etc. Examples include toluene, benzene, xylene, methyl ethyl ketone, tetrahydrofuran, ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve, dioxane, cyclohexanone, and ethyl acetate. Among these, it is preferable to use cyclohexanone from the viewpoint of film-forming property, and it is preferable that a part or all of the materials contained in the semiconductor adhesive are soluble in cyclohexanone. That is, it is preferable that a part or all of the material contained in the resin varnish is a cyclohexanone solution. These organic solvents can be used alone or in combination of two or more. Stirring and mixing and kneading in the preparation of the resin varnish can be carried out by using, for example, a stirrer, a raker, a triple roll, a ball mill, a bead mill or a homodisper.

The base film is not particularly limited as long as it has heat resistance that can withstand the heating conditions when the organic solvent is volatilized, and is a polyester film, polypropylene film, polyethylene terephthalate film, polyimide film, polyetherimide film, poly. Examples thereof include ether naphthalate film and methylpentene film. The base film is not limited to a single layer composed of one of these films, and may be a multilayer film composed of two or more types of films.

Specifically, as a condition for volatilizing the organic solvent from the resin varnish after coating, it is preferable to heat at 50 to 200 ° C. for 0.1 to 90 minutes. If there is no effect on voids, viscosity adjustment, etc. after mounting, it is preferable that the organic solvent volatilizes to 1.5% by mass or less.

The thickness of the film in the film-like adhesive according to the present embodiment is preferably 10 to 100 μm, more preferably 20 to 50 μm, from the viewpoint of visibility, fluidity, and filling property.

<Semiconductor device>
The semiconductor adhesive according to the present embodiment is suitably used for semiconductor devices and is suitable as a semiconductor adhesive, in which electrodes at the connection portions of the semiconductor chip and the wiring circuit board are electrically connected to each other. It is particularly preferably used for sealing a connection portion in a semiconductor device or a semiconductor device in which electrodes of each connection portion of a plurality of semiconductor chips are electrically connected to each other. Hereinafter, the semiconductor device using the semiconductor adhesive according to the present embodiment will be described. The electrodes of the connection portion in the semiconductor device may be either a metal bond between the bump and the wiring or a metal bond between the bump and the bump. In the semiconductor device, for example, a flip-chip connection for obtaining an electrical connection via a semiconductor adhesive may be used.

FIG. 1 is a schematic cross-sectional view showing an embodiment of a semiconductor device (COB type connection mode of a semiconductor chip and a substrate). As shown in FIG. 1A, the first semiconductor device 100 is arranged on the semiconductor chip 10 and the substrate (wiring circuit board) 20 facing each other and the surfaces of the semiconductor chip 10 and the substrate 20 facing each other, respectively. It has a wiring 15, a connection bump 30 that connects the semiconductor chip 10 and the wiring 15 of the substrate 20 to each other, and an adhesive 40 that fills the gap between the semiconductor chip 10 and the substrate 20 without gaps. The semiconductor chip 10 and the substrate 20 are flip-chip connected by the wiring 15 and the connection bump 30. The wiring 15 and the connection bump 30 are sealed with the semiconductor adhesive 40 and are shielded from the external environment.

As shown in FIG. 1B, the second semiconductor device 200 is arranged on the semiconductor chip 10 and the substrate (wiring circuit board) 20 facing each other and the surfaces of the semiconductor chip 10 and the substrate 20 facing each other, respectively. It has a bump 32 and a semiconductor adhesive 40 in which the gap between the semiconductor chip 10 and the substrate 20 is filled without gaps. The semiconductor chip 10 and the substrate 20 are flip-chip connected by connecting the opposing bumps 32 to each other. The bump 32 is sealed with the semiconductor adhesive 40 and is shielded from the external environment.

FIG. 2 is a schematic cross-sectional view showing another embodiment of the semiconductor device (COC type connection mode between semiconductor chips). As shown in FIG. 2A, the third semiconductor device 300 is the same as the first semiconductor device 100 except that the two semiconductor chips 10 are flip-chip connected by the wiring 15 and the connection bump 30. is there. As shown in FIG. 2B, the fourth semiconductor device 400 is similar to the second semiconductor device 200 except that the two semiconductor chips 10 are flip-chip-connected by bumps 32.

The semiconductor chip 10 is not particularly limited, and various semiconductors such as elemental semiconductors composed of elements of the same type such as silicon and germanium, and compound semiconductors such as gallium arsenide and indium phosphorus can be used.

The substrate 20 is not particularly limited as long as it is a wiring circuit board, and is formed on the surface of an insulating substrate containing glass epoxy resin, polyimide resin, polyester resin, ceramic, epoxy resin, bismaleimide triazine resin and the like as main components. A circuit board on which wiring (wiring pattern) is formed by removing unnecessary parts of the metal layer by etching, a circuit board on which wiring (wiring pattern) is formed by metal plating or the like on the surface of the insulating substrate, and a surface of the insulating substrate. A circuit board or the like on which a conductive material is printed on the surface and wiring (wiring pattern) is formed can be used.

The connection parts of the wiring 15, bump 32, etc. are mainly composed of gold, silver, copper, solder (main components are tin-silver, tin-lead, tin-bismuth, tin-copper), nickel, tin, lead, etc. It may contain a plurality of metals.

The main components of the surface of the wiring (wiring pattern) are gold, silver, copper, solder (main components are tin-silver, tin-lead, tin-bismuth, tin-copper), tin, nickel, etc. A metal layer may be formed. This metal layer may be composed of only a single component, or may be composed of a plurality of components. Further, it may have a structure in which a plurality of metal layers are laminated. Copper and solder are generally used because they are inexpensive. Since copper and solder contain oxides, impurities and the like, it is preferable that the adhesive for semiconductors has flux activity.

The main components of the material of the conductive protrusions called bumps are gold, silver, copper, solder (main components are, for example, tin-silver, tin-lead, tin-bismuth, tin-copper), tin, nickel, etc. Is used, and may be composed of only a single component, or may be composed of a plurality of components. Further, these metals may be formed so as to form a laminated structure. The bumps may be formed on a semiconductor chip or a substrate. Copper and solder are generally used because they are inexpensive. Since copper and solder contain oxides, impurities and the like, it is preferable that the adhesive for semiconductors has flux activity.

Further, the semiconductor devices (packages) as shown in FIGS. 1 or 2 are laminated to form gold, silver, copper, solder (main components are, for example, tin-silver, tin-lead, tin-bismuth, tin-copper). It may be electrically connected with tin, nickel or the like. For example, as seen in TSV technology, an adhesive may be flip-chip connected or laminated between semiconductor chips to form holes through the semiconductor chips and connected to electrodes on a patterned surface.

FIG. 3 is a schematic cross-sectional view showing another embodiment of the semiconductor device (semiconductor chip laminated type mode (TSV)). As shown in FIG. 3, in the fifth semiconductor device 500, the wiring 15 formed on the interposer 50 is connected to the wiring 15 of the semiconductor chip 10 via the connection bump 30, so that the semiconductor chip 10 and the interposer 50 are connected to each other. Is flip-chip connected. The gap between the semiconductor chip 10 and the interposer 50 is filled with the semiconductor adhesive 40 without any gap. The semiconductor chip 10 is repeatedly laminated on the surface of the semiconductor chip 10 on the side opposite to the interposer 50 via the wiring 15, the connection bump 30, and the semiconductor adhesive 40. The wiring 15 on the pattern surface on the front and back of the semiconductor chip 10 is connected to each other by a through electrode 34 filled in a hole penetrating the inside of the semiconductor chip 10. As the material of the through electrode 34, copper, aluminum, or the like can be used.

With such TSV technology, it is possible to acquire a signal from the back surface of a semiconductor chip that is not normally used. Further, since the through electrode 34 is passed vertically through the semiconductor chip 10, the distance between the opposing semiconductor chips 10 or between the semiconductor chip 10 and the interposer 50 can be shortened, and flexible connection is possible. The semiconductor adhesive according to the present embodiment is suitably used as a sealing material between the opposing semiconductor chips 10 or between the semiconductor chips 10 and the interposer 50 in such TSV technology.

<Manufacturing method of semiconductor devices>
In the method for manufacturing a semiconductor device according to the present embodiment, a semiconductor chip and a wiring circuit board, or a plurality of semiconductor chips are connected to each other by using the semiconductor adhesive according to the present embodiment. In the method for manufacturing a semiconductor device according to the present embodiment, for example, a semiconductor chip and a wiring circuit board are connected to each other via an adhesive, and each connection portion of the semiconductor chip and the wiring circuit board is electrically connected to each other to form a semiconductor. A step of obtaining an apparatus or a step of connecting a plurality of semiconductor chips to each other via an adhesive and electrically connecting the connecting portions of the plurality of semiconductor chips to each other to obtain a semiconductor apparatus is provided.

In the method for manufacturing a semiconductor device according to the present embodiment, the connecting portions can be connected to each other by metal bonding. That is, the respective connection portions of the semiconductor chip and the wiring circuit board are connected to each other by metal bonding, or the respective connection portions of the plurality of semiconductor chips are connected to each other by metal bonding.

As an example of the method for manufacturing the semiconductor device according to the present embodiment, the method for manufacturing the sixth semiconductor device 600 shown in FIG. 4 will be described. In the sixth semiconductor device 600, a substrate (for example, a glass epoxy substrate) 60 having wiring (copper wiring) 15 and a semiconductor chip 10 having wiring (for example, copper pillars and copper posts) 15 are interposed via a semiconductor adhesive 40. Are connected to each other. The wiring 15 of the semiconductor chip 10 and the wiring 15 of the substrate 60 are electrically connected by a connection bump (solder bump) 30. A solder resist 70 is arranged on the surface of the substrate 60 on which the wiring 15 is formed, except for the position where the connection bump 30 is formed.

In the sixth method for manufacturing the semiconductor device 600, first, a semiconductor adhesive (film-like adhesive or the like) 40 is attached onto the substrate 60 on which the solder resist 70 is formed. The sticking can be performed by a heating press, roll laminating, vacuum laminating or the like. The supply area and thickness of the semiconductor adhesive 40 are appropriately set according to the size of the semiconductor chip 10 or the substrate 60, the bump height, and the like. The semiconductor adhesive 40 may be attached to the semiconductor chip 10, and the semiconductor adhesive 40 is attached by dicing the semiconductor wafer after attaching the semiconductor adhesive 40 and then dicing the semiconductor wafer into individual pieces. The semiconductor chip 10 may be manufactured. In this case, if the adhesive has a high light transmittance, the visibility is ensured even if the alignment mark is covered, so that the range of attachment is not only on the semiconductor wafer (semiconductor chip) but also on the substrate. There are no restrictions and it is easy to handle.

After the semiconductor adhesive 40 is attached to the substrate 60 or the semiconductor chip 10, the connection bump 30 on the wiring 15 of the semiconductor chip 10 and the wiring 15 of the substrate 60 are aligned by using a connection device such as a flip chip bonder. To do. Then, the semiconductor chip 10 and the substrate 60 are pressed while being heated at a temperature equal to or higher than the melting point of the connection bump 30 (when solder is used for the connection portion, it is preferable that the solder portion is heated to a temperature of 240 ° C. or higher). The 10 and the substrate 60 are connected, and the gap between the semiconductor chip 10 and the substrate 60 is sealed and filled with the semiconductor adhesive 40. The connection load depends on the number of bumps, but is set in consideration of absorption of bump height variation, control of bump deformation amount, and the like. The connection time is preferably short from the viewpoint of improving productivity. It is preferable to melt the solder to remove oxide films, surface impurities and the like, and to form a metal joint at the connection portion.

The short connection time (crimping time) means that the time (for example, the time when solder is used) that the temperature of 240 ° C. or higher is applied to the connection portion during the connection formation (main crimping) is 10 seconds or less. The connection time is preferably 5 seconds or less, more preferably 3 seconds or less.

After alignment, the semiconductor device may be manufactured by temporarily fixing and heat-treating in a reflow furnace to melt the solder bumps and connecting the semiconductor chip and the substrate. Since the temporary fixing does not significantly require the need to form a metal joint, it may have a lower load, a shorter time, and a lower temperature than the above-mentioned main crimping, and has advantages such as improvement in productivity and prevention of deterioration of the connection portion. .. After connecting the semiconductor chip and the substrate, heat treatment may be performed in an oven or the like to cure the adhesive. The heating temperature is a temperature at which the adhesive is cured, preferably almost completely. The heating temperature and heating time may be set as appropriate. In this case, the resulting semiconductor device comprises a cured product of the adhesive.

Hereinafter, the present disclosure will be described in more detail with reference to examples. However, the present disclosure is not limited to these examples.

The compounds used in each Example and Comparative Example are as follows.
(A) Epoxy resin / triphenol methane skeleton-containing polyfunctional solid epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name "EP1032H60", hereinafter referred to as "EP1032")
-Naphthalene skeleton-containing epoxy resin (manufactured by DIC Corporation, trade name "HP4032D")
-Bisphenol F type liquid epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name "YL983U", hereinafter referred to as "YL983")
-Flexible epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name "YL7175", hereinafter referred to as "YL7175")

(B) Hardener ・ 2,4-diamino-6- [2'-methylimidazolyl- (1')] -ethyl-s-triazine isocyanuric acid adduct (manufactured by Shikoku Chemicals Corporation, trade name "2MAOK-PW" , Hereinafter referred to as "2MAOK")

(C) High molecular weight component / acrylic resin having a weight average molecular weight of 10,000 or more (manufactured by Kuraray Co., Ltd., trade name "Clarity LA4285", Mw / Mn = 1.28, weight average molecular weight Mw: 80000)

(D) Filler Inorganic filler / epoxy surface-treated nanosilica filler (manufactured by Admatex Co., Ltd., trade name "50 nm SE-AH1", average particle size: about 50 nm, hereinafter referred to as "SE nanosilica")
-Inorganic silica filler (manufactured by Admatex Co., Ltd., trade name "SE2050", average particle size: 0.5 μm, hereinafter referred to as "SE2050")
-Inorganic silica filler (manufactured by Admatex Co., Ltd., trade name "SE2050SEJ", average particle size: 0.5 μm, hereinafter referred to as "SE2050SEJ")

(E) Flux agent / glutaric acid (manufactured by Sigma-Aldrich Japan GK, melting point: approx. 97 ° C)

<Making a film-like adhesive>
(Example 1)
Epoxy resin 11.25g ("EP1032" 6.8g, "HP4032D" 0.75g, "YL983" 1.5g, "YL7175" 2.2g), curing agent "2MAOK" 0.6g, glutaric acid 0.45 g, 35.3 g of inorganic filler "SE nanosilica", 2.0 g of acrylic resin "LA4285", and cyclohexanone (amount that makes the solid content in the resin varnish 47% by mass) are charged, and the diameter is 1.0 mm. The beads were added in the same mass as the solid content, and the mixture was stirred with a bead mill (Fritsch Japan Co., Ltd., planetary fine pulverizer P-7) for 30 minutes. Then, the beads used for stirring were removed by filtration to obtain a resin varnish.

The obtained resin varnish is coated on a base film (manufactured by Teijin DuPont Film Co., Ltd., trade name "Purex A54") with a small precision coating device (manufactured by Yasui Seiki Co., Ltd.), and the coated resin is applied. The varnish was dried (100 ° C./5 minutes) in a clean oven (manufactured by Espec Co., Ltd.) to obtain a film-like adhesive. It was prepared to have a thickness of 0.02 mm.

(Example 2)
A film-like adhesive was produced in the same manner as in Example 1 except that the epoxy resin “HP4032D” was increased to 1.5 g and the epoxy resin “YL983” was reduced to 0.75 g.

(Comparative Example 1)
Examples except that the epoxy resins "YL7175" and "HP4032D" were not blended and 2.3 g of an inorganic silica filler (manufactured by Admatex Co., Ltd., trade name "SE2050", average particle size: 0.5 μm) was added. A film-like adhesive was produced in the same manner as in 1.

(Comparative Example 2)
Add 3.3g of inorganic silica filler (manufactured by Admatex Co., Ltd., trade name "SE2050SEJ", average particle size: 0.5μm), reduce "SE nanosilica" to 27.9g, and reduce "LA4285" to 0.5g. A film-like adhesive was produced in the same manner as in Example 1 except for the above.

Table 1 summarizes the formulations of Examples 1 and 2 and Comparative Examples 1 and 2.

<Evaluation>
The evaluation methods of the film-like adhesives obtained in Examples and Comparative Examples are shown below.

(1) Preparation of thixotropy value measurement sample The produced film-like adhesive is used with a desktop laminator (manufactured by Mirror Corporation, trade name "Hot Dog GK-13DX") until the total thickness reaches 0.4 mm (400 μm). A plurality of sheets were laminated (laminated), and cutout measurement samples were obtained in a size of 7.3 mm in length and 7.3 mm in width.

(2) Measurement of thixotropy value For the obtained measurement sample, a shear viscosity measuring device (manufactured by TA Instruments Japan Co., Ltd., trade name "ARES") was used to set the frequency to 1 Hz under a constant temperature of 120 ° C. The viscosity was measured when the viscosity was continuously changed from 1 to 70 Hz at 0.1 Hz per second, and the value obtained by dividing the viscosity value at 7 Hz by the viscosity value at 70 Hz was taken as the thixotropy value.

(3) Manufacturing method of semiconductor device The produced film-like adhesive is cut out (length 7.3 mm, width 7.3 mm, thickness 0.045 mm), and a semiconductor chip with solder bumps (chip size: length 7.3 mm, width 7. 3 mm, thickness 0.15 mm, bump height: copper pillar + solder total about 45 μm, number of bumps 328, pitch 80 μm). Next, a semiconductor chip with solder bumps to which a film-like adhesive is attached is mounted on a glass epoxy substrate (glass epoxy substrate thickness: 420 μm, copper wiring thickness: 9 μm) with a flip chip bonder FCB3 (manufactured by Panasonic Corporation). (Mounting conditions: crimp head temperature 350 ° C./5 seconds / 0.5 MPa), and the same semiconductor device as in FIG. 4 was obtained. The stage temperature was 80 ° C.

(4) Evaluation method of coverage The semiconductor device obtained by the above method (3) Manufacturing method of the semiconductor device is observed from above the upper chip with a microscope (manufactured by KEYENCE CORPORATION), and the resin protrudes from the end of the chip. The width was measured. _{The protrusion width is the resin protrusion width W 1} (unit: μm) from the center of one side of the chip and the resin protrusion width W from the position 0.2 mm center from one end (corner of the chip) of the one side. ₂ (unit: μm) was measured, and the ratio of the two (W ₂ / W ₁ ) was determined. W ₂ is the smaller of the resin protrusion width from the position 0.2 mm center side from one end of the one side of the chip and the resin protrusion width from the position 0.2 mm center side from the other end. The value of the one. This ratio (W ₂ / W ₁ ) was measured on all four sides of the chip, and the average value was calculated as "coverability".

The coverage is an index indicating whether or not the adhesive resin has spread to the corners of the chip in the semiconductor device. Since it is preferable that there is no difference in the protrusion width between the corner portion and the center portion of the side of the semiconductor device, the coverage property is better as it is closer to 1.

Table 1 shows the measurement results of thixotropy value and the evaluation results of coverage.

From the evaluation results in Table 1, the coverage of Example 1 and Example 2 having a thixotropy value of 3.1 or less was over 0.4, but the thixotropy value was larger than 3.1. In Example 2, the coverage was less than 0.4. From these facts, it was confirmed that the film-shaped semiconductor adhesive of the present disclosure having a low thixotropy value has high coverage.

10 ... Semiconductor chip, 15 ... Wiring, 20, 60 ... Substrate, 30 ... Connection bump, 32 ... Bump, 34 ... Through electrode, 40 ... Semiconductor adhesive, 50 ... Interposer, 70 ... Solder resist, 100, 200, 300 , 400, 500, 600 ... Semiconductor device.

Claims (8)

In a semiconductor device in which the electrodes of the respective connection portions of the semiconductor chip and the wiring circuit board are electrically connected to each other, or in a semiconductor device in which the electrodes of the respective connection portions of a plurality of semiconductor chips are electrically connected to each other. , A semiconductor adhesive used to seal at least a part of the connection portion.
The thixotropy value of the semiconductor adhesive is 1.0 or more and 3.1 or less.
The thixotropy value measures the viscosity of a sample in which the semiconductor adhesive is laminated to a thickness of 400 μm when the frequency is continuously changed from 1 Hz to 70 Hz under a constant temperature of 120 ° C. with a shear viscosity measuring device. An adhesive for semiconductors, which is a value obtained by dividing the viscosity value at 7 Hz by the viscosity value at 70 Hz. The semiconductor adhesive according to claim 1, which contains (a) an epoxy resin, (b) a curing agent, and (c) a high molecular weight component having a weight average molecular weight of 10,000 or more. The semiconductor adhesive according to claim 2, further comprising (d) a filler. The semiconductor adhesive according to claim 2 or 3, further comprising (e) a flux agent. (C) The semiconductor adhesive according to any one of claims 2 to 4, wherein the polydispersity Mw / Mn of the high molecular weight component having a weight average molecular weight of 10,000 or more is 3 or less. The semiconductor adhesive according to any one of claims 2 to 5, wherein a part or all of the material contained in the semiconductor adhesive is soluble in cyclohexanone. The semiconductor adhesive according to any one of claims 1 to 6, which is in the form of a film. Using the semiconductor adhesive according to any one of claims 1 to 7, the semiconductor chip and the wiring circuit board are aligned by the connecting device via the semiconductor adhesive, and are connected to each other and the semiconductor chip and the semiconductor chip. The step of electrically connecting the electrodes of the respective connection portions of the wiring circuit board to each other and sealing at least a part of the connection portions with the semiconductor adhesive, or via the semiconductor adhesive by a connecting device. The plurality of semiconductor chips are aligned with each other, connected to each other, and the electrodes of the connecting portions of the plurality of semiconductor chips are electrically connected to each other, and at least a part of the connecting portions is sealed with the semiconductor adhesive. A method of manufacturing a semiconductor device, comprising a step of stopping.

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