TW201936865A - Adhesive for semiconductor and method for manufacturing semiconductor device using same - Google Patents

Abstract

An adhesive for a semiconductor, said adhesive being to be used for at least partly sealing connection parts of a semiconductor device wherein electrodes in respective connection parts of a semiconductor chip and a wiring circuit board are electrically connected to each other or a semiconductor device wherein electrodes in respective connection parts of a plurality of semiconductor chips are electrically connected to each other. This adhesive for a semiconductor has a thixotropy value of 1.0-3.1 inclusive, wherein the thixotropy value means a value calculated by measuring the viscosity of a sample, said sample being prepared by laminating the adhesive for a semiconductor to a depth of 400 [mu]m, with a shear viscometer under constant conditions at a temperature of 120 DEG C while continuously changing frequency from 1 Hz to 70 Hz, and then dividing the viscosity at 7 Hz by the viscosity at 70 Hz.

Description

Adhesive for semiconductor and method of manufacturing semiconductor device using the same

The present disclosure relates to a semiconductor adhesive and a method of manufacturing a semiconductor device using the same.

Conventionally, when connecting a semiconductor chip to a substrate, a wire bonding method using a thin metal wire such as gold wire is widely used. On the other hand, in order to meet the requirements for higher functionality, higher integration, and higher speed for semiconductor devices, conductive bumps called bumps are formed on the semiconductor wafer or the substrate and directly between the semiconductor wafer and the substrate The flip chip connection method (FC (flip chip) connection method) for connection is being promoted.

As a flip-chip connection method, a method of metal bonding using solder, tin, gold, silver, copper, etc., a method of applying ultrasonic vibration to perform metal bonding, and a method of maintaining mechanical contact by the shrinking force of a resin are known However, from the viewpoint of the reliability of the connection portion, a method of metal bonding using solder, tin, gold, silver, copper, or the like is generally used.

For example, in the connection between semiconductor wafers and substrates, chip on board (COB) type connections commonly used in ball grid array (BGA), chip size package (CSP), etc. The method is also flip chip connection. In addition, the flip-chip connection method is also widely used in a chip on chip (COC) type connection method for forming a connection portion (bump or wiring) on a semiconductor wafer and connecting between the semiconductor wafers (for example, see below The patent document 1).

In a package that strongly requires further miniaturization, thinness, and high functionality, the stacking and multi-level chip stacking package, package on package (POP), and through-silicon via of the connection method are laminated Through-Silicon Via (TSV) has also begun to spread widely. By arranging the three-dimensional instead of the planar shape, the package can be reduced, so these technologies are often used. They are also effective in improving the performance of semiconductors, reducing noise, reducing the installation area, and saving power. As the next generation Attention has been paid to semiconductor wiring technology.
[Prior Art Literature]
[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2016-102165

[Problems to be solved by the invention]
In a flip chip package that promotes higher functionality, higher integration, and lower cost, it is required to suppress the resin bleed width at the time of wafer mounting and to mount the wafer at a high density for the purpose of high productivity. Therefore, if the load at the time of pressure bonding is reduced, the resin bleed width is suppressed, but there is a fear that the resin is insufficient at the corners of the wafer, causing wafer peeling and the like.

The main object of the present disclosure is to provide an adhesive for semiconductors that controls the shape of the oozing resin during wafer mounting to ooze the resin along the side surface of the wafer, thereby obtaining a semiconductor device that does not have insufficient resin during mounting, And a method of manufacturing a semiconductor device using the adhesive for semiconductors.
[Means to solve the problem]

One aspect of the present disclosure is [1] an adhesive for semiconductors, a semiconductor device in which electrodes of respective connection portions of a semiconductor wafer and a printed circuit board are electrically connected to each other, or electrodes of respective connection portions of a plurality of semiconductor wafers In a semiconductor device that is electrically connected to each other, the semiconductor adhesive is used to seal at least a portion of the connection portion, and the thixotropic value of the semiconductor adhesive is 1.0 or more and 3.1 or less. The value of change is measured for a sample formed by stacking the adhesive for semiconductors up to a thickness of 400 μm, using a shear viscosity measuring device under a fixed temperature of 120°C to continuously change the frequency from 1 Hz to 70 Hz Viscosity, and the value obtained by dividing the viscosity value at 7 Hz by the viscosity value at 70 Hz.

In addition, another aspect of the present disclosure is [2] the adhesive for semiconductors described in [1] above, which contains (a) an epoxy resin, (b) a curing agent, and (c) a weight average molecular weight of 10,000 or more High molecular weight components.

In addition, another aspect of the present disclosure is [3] the adhesive for semiconductors described in [2] above, which further contains (d) a filler.

In addition, another aspect of the present disclosure is [4] the adhesive for semiconductors according to [2] or [3], which further contains (e) a flux.

In addition, another aspect of the present disclosure is [5] the adhesive for semiconductor according to any one of [2] to [4], wherein the (c) high molecular weight component having a weight average molecular weight of 10,000 or more The polydispersity Mw/Mn is 3 or less.

In addition, another aspect of the present disclosure is [6] the adhesive for semiconductor according to any one of [2] to [5], wherein a part or all of the material contained in the adhesive for semiconductor may be Soluble in cyclohexanone.

In addition, another aspect of the present disclosure is [7] the adhesive for semiconductors according to any one of [1] to [6], which is in the form of a film.

Furthermore, another aspect of the present disclosure is [8] a method for manufacturing a semiconductor device, comprising: using the adhesive for semiconductor according to any one of [1] to [7], using a connecting device and passing through The semiconductor adhesive aligns and interconnects a semiconductor wafer and a printed circuit board, and electrically connects the electrodes of the connection portions of the semiconductor wafer and the printed circuit board to each other, and uses the semiconductor adhesive A step of sealing at least a portion of the connection portion; or, by aligning and connecting a plurality of semiconductor wafers via the semiconductor adhesive using a connection device, electrically connecting electrodes of the connection portions of the plurality of semiconductor wafers to each other The step of sealing the at least a part of the connection part by the semiconductor adhesive.
[Effect of invention]

According to the present disclosure, by controlling the thixotropic value of the adhesive for semiconductors, the shape of the resin oozing to the outer peripheral portion of the wafer during the mounting of the semiconductor device is controlled, so that the resin oozes in a shape along the side surface of the wafer, thereby suppressing insufficient resin. In addition, according to the present disclosure, a semiconductor device using such an adhesive for semiconductors and a method of manufacturing the same can be provided.

Hereinafter, the preferred embodiments of the present disclosure will be described in detail with reference to the drawings as appropriate. In addition, in the drawings, the same or corresponding parts are denoted by the same symbols, and repeated explanations are omitted. In addition, the positional relationship such as up, down, left, and right is based on the positional relationship shown in the drawings unless otherwise specified. Furthermore, the size ratio of the drawings is not limited to the ratio shown.

In this specification, the numerical range indicated by "~" indicates a range including the numerical values described before and after "~" as the minimum value and the maximum value, respectively. In the numerical range described in stages in this specification, the upper limit value or the lower limit value of the numerical range of a certain stage may be arbitrarily combined with the upper limit value or the lower limit value of the numerical range of another stage. In the numerical range described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples. The "A or B" may be any one of A and B, or both. Unless otherwise specified, the materials exemplified in this specification may be used alone or in combination of two or more. In this specification, "(meth)acrylic acid" means acrylic acid or methacrylic acid corresponding thereto.

<Adhesive for semiconductors>
The semiconductor adhesive of the present embodiment is a semiconductor device in which electrodes of the connection portions of the semiconductor wafer and the printed circuit board are electrically connected to each other, or electrodes of the connection portions of the plurality of semiconductor wafers are electrically connected to each other In a semiconductor device for sealing at least a part of the connection portion.

The thixotropic value of the adhesive for semiconductors of this embodiment is 1.0 or more and 3.1 or less. The thixotropic value is measured for a sample formed by stacking the adhesive for semiconductors up to a thickness of 400 μm using a shear viscosity measuring device under a fixed temperature of 120°C to continuously change the frequency from 1 Hz to 70 Hz Viscosity, and the value obtained by dividing the viscosity value at 7 Hz by the viscosity value at 70 Hz. If the thixotropic value is 3.1 or less, the adhesive for semiconductors can sufficiently flow even at the corner of the wafer with the smallest shear applied during wafer mounting, and the resin oozes in a shape along the side of the wafer. Furthermore, the thixotropic value may be 1.5 or more, 2.0 or more, or 2.5 or more.

The adhesive for semiconductor of this embodiment may contain (a) epoxy resin, (b) hardener, (c) high molecular weight component with a weight average molecular weight of 10,000 or more, preferably (d) filler, (e) auxiliary Flux.

((A) component: epoxy resin)
Examples of the epoxy resin of the component (a) include epoxy resins having two or more epoxy groups in the molecule. Bisphenol A epoxy resin, bisphenol F epoxy resin, and naphthalene epoxy resin can be used. , Phenol novolac epoxy resin, cresol novolac epoxy resin, phenol aralkyl epoxy resin, biphenyl epoxy resin, triphenylmethane epoxy resin, dicyclopentadiene ring Oxygen resin, various multifunctional epoxy resins, etc. (A) One component may be used alone or in combination of two or more.

Based on the total solid content of the adhesive for semiconductors, the content of (a) component is preferably 10% by mass to 50% by mass, more preferably 15% by mass to 45% by mass, and still more preferably 20% by mass to 40% by mass quality%. (A) If the content of the component is 10% by mass or more, it is easy to sufficiently control the flow of the resin after curing, and if it is 50% by mass or less, the resin component of the cured product will not be excessive, and it is easy to reduce the warpage of the package. In addition, by setting the content of (a) component within the above range, it is easy to control the thixotropic value of the adhesive for semiconductors to 1.0 or more and 3.1 or less. When the resin component is small and the filler content is large, the thixotropic value tends to be small. Therefore, by setting the content of the (a) component to 50% by mass or less, it is easy to reduce the thixotropic value.

((B) Ingredient: Hardener)
The adhesive for semiconductors of this embodiment contains (b) a curing agent. Examples of the curing agent include phenol resin-based curing agents, acid anhydride-based curing agents, amine-based curing agents, imidazole-based curing agents, and phosphine-based curing agents. If the component (b) contains phenolic hydroxyl groups, acid anhydrides, amines, or imidazoles, the flux activity that suppresses the formation of an oxide film in the connection portion is easily exhibited, so that connection reliability and insulation reliability can be easily improved. Each hardener will be described below.

(Bi) Phenol resin-based hardeners As phenol resin-based hardeners, there can be exemplified hardeners having two or more phenolic hydroxyl groups in the molecule. Phenol novolak resin, cresol novolak resin, phenol aralkyl resin, Cresol naphthol formaldehyde polycondensate, triphenylmethane type polyfunctional phenol resin, various polyfunctional phenol resins, etc. The phenol resin-based hardener may be used alone or in combination of two or more.

From the viewpoint of excellent curability, adhesion, and storage stability, the equivalent ratio of the phenol resin-based curing agent to the component (a) (phenolic hydroxyl group/epoxy group, molar ratio) is preferably 0.3 to 1.5, more preferably 0.4 to 1.0, and still more preferably 0.5 to 1.0. If the equivalent ratio is 0.3 or more, the curability is improved, and the adhesion tends to be improved. If it is 1.5 or less, unreacted phenolic hydroxyl groups do not remain excessively, the water absorption is suppressed to a low value, and the insulation reliability is further improved. Increasing tendency.

(B-ii) Anhydride-based hardeners can be used as anhydride-based hardeners: methylcyclohexanetetracarboxylic dianhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic dianhydride, Ethylene glycol bistrimellitic anhydride, etc. An acid anhydride hardener can be used alone or in combination of two or more.

From the viewpoint of excellent curability, adhesion, and storage stability, the equivalent ratio of the acid anhydride-based curing agent to the component (a) (anhydride group/epoxy group, molar ratio) is preferably 0.3 to 1.5, It is more preferably 0.4 to 1.0, and still more preferably 0.5 to 1.0. If the equivalence ratio is 0.3 or more, the curability is improved, and the adhesive force tends to increase. If it is 1.5 or less, unreacted acid anhydride does not remain excessively, the water absorption rate is suppressed to a low value, and the insulation reliability is further improved. tendency.

(B-iii) Amine-based hardener As the amine-based hardener, dicyandiamine, various amine compounds, and the like can be used.

From the viewpoint of excellent curability, adhesion, and storage stability, the equivalent ratio of the amine-based curing agent to the component (a) (amine/epoxy group, molar ratio) is preferably 0.3 to 1.5, and more It is preferably 0.4 to 1.0, and more preferably 0.5 to 1.0. If the equivalent ratio is 0.3 or more, the curability is improved, and the adhesion tends to be improved. If it is 1.5 or less, unreacted amine does not remain excessively, and the insulation reliability tends to be further improved.

(B-iv) Imidazole-based hardeners As imidazole-based hardeners, 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 Acid ester, 1-cyanoethyl-2-phenylimidazolium trimellitate, 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-triazine isocyanurate adduct, 2-phenylimidazole isocyanurate adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl- Adducts of 4-methyl-5-hydroxymethylimidazole, epoxy resin and imidazole, etc. Among these, from the viewpoint of more excellent curability, storage stability, and connection reliability, 1-cyanoethyl-2-undecylimidazole and 1-cyano-2-phenylimidazole are preferred , 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 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 isocyanurate adduct, 2-phenylimidazole isocyanurate adduct, 2-phenyl-4,5-dihydroxymethylimidazole and 2-phenyl-4-methyl-5-hydroxymethylimidazole. The imidazole-based hardener can be used alone or in combination of two or more. In addition, it may be a latent curing agent obtained by microencapsulating these.

The content of the imidazole-based hardener is preferably 0.1 to 20 parts by mass, and more preferably 0.1 to 10 parts by mass relative to 100 parts by mass of the component (a). If the content of the imidazole-based hardener is 0.1 parts by mass or more, the curability tends to be improved, and if it is 20 parts by mass or less, the adhesive composition will not harden before the formation of the metal joint, and there is a tendency for poor connection.

(Bv) Phosphine-based hardeners As phosphine-based hardeners, triphenylphosphine, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra(4-methylphenyl) borate and tetraphenyl Phosphonium (4-fluorophenyl) borate, etc.

The content of the phosphine-based hardener is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass relative to 100 parts by mass of the component (a). If the content of the phosphine-based hardener is 0.1 parts by mass or more, the curability tends to be improved, and if it is 10 parts by mass or less, the semiconductor adhesive will not be cured before the formation of metal bonding, and there is a tendency that connection failure is less likely to occur.

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

As the component (b), from the viewpoint of excellent curability, it is preferable to use a phenol resin-based hardener and an imidazole-based hardener, an acid anhydride-based hardener and an imidazole-based hardener, and an amine-based hardener and an imidazole-based hardener Agents, imidazole-based hardeners alone. If the connection is made in a short period of time, the productivity is improved, so it is more preferable to use an imidazole-based hardener excellent in rapid hardening property alone. In this case, if curing in a short time, volatile components such as low-molecular components can be suppressed, so the generation of voids can also be easily suppressed.

((C) component: high molecular weight component with a weight average molecular weight of 10,000 or more)
Examples of (c) high-molecular-weight components with a weight average molecular weight of 10,000 or more (excluding compounds corresponding to (a) components) include phenoxy resins, polyimide resins, polyamide resins, and polycarbodiimide. Resin, cyanate resin, (meth)acrylic resin, polyester resin, polyethylene resin, polyether resin, polyetherimide resin, polyvinyl acetal resin, polyurethane resin, Acrylic rubber and the like, among them, from the viewpoint of excellent heat resistance and film formability, preferably phenoxy resin, polyimide resin, (meth)acrylic resin, acrylic rubber, cyanate resin , Polycarbodiimide resin, more preferably phenoxy resin, polyimide resin, (meth)acrylic resin, acrylic rubber. (C) The components can also be used alone or in the form of a mixture or copolymer of two or more.

(C) The mass ratio of the component to (a) component is not particularly limited. In order to maintain the film shape, the content of (a) component is preferably 0.01 to 5 parts by mass relative to 1 part by mass of (c) component, more It is preferably 0.05 to 4 parts by mass, and more preferably 0.1 to 3 parts by mass. If the content of the (a) component is 0.01 parts by mass or more, there is no case where the curability or the adhesive force is reduced, and if the content is 5 parts by mass or less, there is no case where the film formability and film formability are reduced. In addition, the combination of (c) component and (a) component, and their mass ratio can also be used to adjust the thixotropic value.

(C) The weight-average molecular weight of the component is 10,000 or more in terms of polystyrene. In order to individually exhibit good film formability, it is preferably 30,000 or more, more preferably 40,000 or more, and further more than 50,000 or more. When the weight average molecular weight is 10,000 or more, there is no fear that the film formability is reduced. In addition, in this specification, the weight average molecular weight refers to the weight average molecular weight when measured by polystyrene conversion using high-performance liquid chromatography (C-R4A manufactured by Shimadzu Corporation).

(C) The polydispersity Mw/Mn of the component is preferably 3 or less, and more preferably 2.5 or less. If Mw/Mn is 3 or less, it is considered that there is little variation in molecular weight and the thixotropy value tends to be lowered easily.

((D) composition: filler)
Examples of the filler of component (d) include insulating inorganic fillers. Among them, an inorganic filler having an average particle diameter of 100 nm or less is more preferable. Examples of insulating inorganic fillers include glass, silica, alumina, titanium oxide, mica, and boron nitride. Among them, silica, alumina, titanium oxide, and boron nitride are preferred, and more preferred are Silicon dioxide, aluminum oxide, boron nitride. The insulating inorganic filler may also be whiskers. Examples of the whiskers 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 more excellent insulation reliability, the component (d) is preferably insulating. The adhesive for semiconductors of this embodiment is preferably a conductive metal filler that does not contain silver filler or solder filler.

From the viewpoint of improving dispersibility and adhesion, the component (d) is preferably a filler subjected to surface treatment. Examples of surface treatment agents include glycidyl (epoxy) compounds (excluding compounds corresponding to (a) component), amine compounds, phenyl compounds, phenylamine compounds, (methyl) Acrylic compounds (for example, compounds having a structure represented by the following general formula (1)), vinyl compounds having a structure represented by the following general formula (2), and the like.

[Chemical 1]

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

Using as having the general formula (1) compound represented by the structure of the surface-treated filler was include R ¹¹ is a hydrogen atom acrylic surface treated filler, R ¹¹ is methyl methacrylate, the surface-treated filler, R ¹¹ is Ethyl acrylic surface treatment fillers such as ethyl are preferably R ¹¹ is not a bulky acrylic surface treatment from the viewpoint of reactivity with the resin contained in the adhesive for semiconductors and the surface of the semiconductor substrate and bond formation Filler, methacrylic acid surface treatment filler. R ^{12 is} also not particularly limited, but those with a higher weight-average molecular weight have less volatile components and are therefore preferred.

[Chem 2]

[R ²¹ , R ²² and R ²³ represent a monovalent organic group, 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 relatively small groups, for example, hydrogen atoms or alkyl groups. In addition, R ²¹ , R ²² and R ²³ may be a monovalent organic group with improved reactivity of the vinyl group. R ^{24 is} also not particularly limited, and from the viewpoint of not easily evaporating and easily reducing pores, those having a higher weight average molecular weight are preferred. In addition, R ²¹ , R ²² , R ²³ and R ²⁴ can be selected according to the ease of surface treatment.

As the surface treatment agent, in terms of ease of surface treatment, a silane treatment agent such as an epoxy-based silane, an amine-based silane, and a (meth)acrylic silane is preferred. The surface treatment agent is preferably a glycidyl-based, phenylamine-based, or (meth)acrylic compound from the viewpoint of excellent dispersibility, fluidity, and adhesion. The surface treatment agent is more preferably a phenyl-based or (meth)acrylic compound from the viewpoint of excellent storage stability.

From the viewpoint of improved visibility, the average particle diameter of the component (d) is preferably 100 nm or less, and more preferably 60 nm or less. From the viewpoint of improvement in adhesion, the component (d) is preferably an inorganic filler having an average particle diameter of 60 nm or less that has been surface-treated with (meth)acrylic silane or epoxy silane. On the other hand, the larger the average particle diameter of the component (d), the smaller the thixotropic value.

Based on the total amount of the adhesive for semiconductors, the content of (d) component is preferably 20% by mass to 80% by mass, more preferably 30% by mass to 75% by mass, and still more preferably 50% by mass to 75% by mass . If the content of the component (d) is 20% by mass or more, there is no fear that the adhesive force will decrease or the reflow resistance will decrease. In addition, if the content of the component (d) is 40% by mass or less, there is no fear that the connection reliability will be lowered due to thickening. (D) The more the content of the component, the smaller the thixotropic value.

((E) Ingredient: Flux)
The adhesive for semiconductors may further contain (e) flux which exhibits flux activity (activity for removing oxides, impurities, etc.). Examples of the flux include nitrogen-containing compounds having non-covalent electron pairs (imidazoles, amines, etc.; except for the compounds contained in the component (b)), carboxylic acids, phenols, and alcohols. In addition, carboxylic acids exhibit fluxing activity more strongly than alcohols, and it is easy to improve connectivity.

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

The adhesive for semiconductors can be further formulated: ion trapping agent, antioxidant, silane coupling agent, titanium coupling agent, leveling agent, etc. These may be used alone or in combination of two or more. About these compounding amounts, it is sufficient to adjust suitably so that the effect of each additive may be shown.

<Method for manufacturing semiconductor adhesive>
From the viewpoint of improving productivity, the adhesive for semiconductors of the present embodiment is preferably in the form of a film (film-like adhesive). The method of producing the film-like adhesive will be described below.

First, after adding (a) component, (b) component, (c) component, and other components as needed to an organic solvent, a resin varnish is prepared by dissolving or dispersing by stirring, mixing, or the like. Thereafter, the base film subjected to the release treatment is coated with a blade coater, a roll coater, an applicator, a die coater, a comma coater, etc. After the resin varnish is applied, the organic solvent is reduced by heating to form a film-like adhesive on the base film. Alternatively, a film-like adhesive may be formed on the wafer by a method in which a resin varnish is spin-coated on the wafer or the like to form a film before the organic solvent is reduced by heating, and then the solvent is dried.

As the organic solvent used in the preparation of the resin varnish, it is preferable to have characteristics that can uniformly dissolve or disperse each component, and examples include dimethylformamide, dimethylacetamide, and N-methyl- 2-pyrrolidone, dimethyl sulfoxide, diethylene glycol dimethyl ether, toluene, benzene, xylene, methyl ethyl ketone, tetrahydrofuran, ethyl cellosolve, ethyl cellosolve acetate, Butyl cellosolve, dioxane, cyclohexanone, and ethyl acetate. Among these, from the viewpoint of film-forming properties, it is preferable to use cyclohexanone, and it is preferable that part or all of the material contained in the adhesive for semiconductor is soluble in cyclohexanone. That is, it is preferable that a part or all of the material contained in the resin varnish is a dissolved cyclohexanone. These organic solvents may be used alone or in combination of two or more. Stirring and kneading when preparing the resin varnish can be performed using, for example, a stirrer, attritor, three-roller, ball mill, bead mill, or homogenizer.

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 examples include polyester films, polypropylene films, polyethylene terephthalate films, and poly Acetamide film, polyetherimide film, polyether naphthalate film, methylpentene film, etc. The base film is not limited to a single-layer film including one of these films, and may be a multilayer film including two or more films.

As conditions for volatilizing the organic solvent from the resin varnish after coating, specifically, heating at 50° C. to 200° C. for 0.1 minutes to 90 minutes is preferably performed. As long as it does not affect the porosity and viscosity adjustment after installation, it is preferable to set the condition that the organic solvent volatilizes to 1.5% by mass or less.

From the viewpoints of visibility, fluidity, and filling properties, the thickness of the film in the film-like adhesive of this embodiment is preferably 10 μm to 100 μm, and more preferably 20 μm to 50 μm.

<Semiconductor device>
The adhesive for semiconductors of this embodiment can be preferably used in a semiconductor device, and is therefore preferably used as an adhesive for semiconductors. For example, the electrodes in the connection portions of the semiconductor wafer and the printed circuit board are electrically connected to each other. The semiconductor device or the semiconductor device in which the electrodes of the connection portions of the plurality of semiconductor wafers are electrically connected to each other can be particularly preferably used for sealing the connection portions. Hereinafter, a semiconductor device using the adhesive for semiconductors of this embodiment will be described. The electrodes of the connection portion in the semiconductor device may be any one of metal bonding of the bump and the wiring, and metal bonding of the bump and the bump. In the semiconductor device, for example, a flip-chip connection that is electrically connected via an adhesive for semiconductor can be used.

1(a) and 1(b) are schematic cross-sectional views showing an embodiment of a semiconductor device (a COB type connection state of a semiconductor wafer and a substrate). As shown in FIG. 1( a ), the first semiconductor device 100 includes a semiconductor wafer 10 and a substrate (wiring circuit board) 20 facing each other, and wires 15 arranged on surfaces of the semiconductor wafer 10 and the substrate 20 facing each other, The connection bump 30 connecting the wiring 15 of the semiconductor wafer 10 and the substrate 20 to each other, and the adhesive 40 filled in the gap between the semiconductor wafer 10 and the substrate 20 without a gap. The semiconductor wafer 10 and the substrate 20 are connected via flip chip via the wiring 15 and the connection bump 30. The wiring 15 and the connection bump 30 are sealed with the adhesive 40 for semiconductors, and are blocked from the external environment.

As shown in FIG. 1( b ), the second semiconductor device 200 includes a semiconductor wafer 10 and a substrate (wiring circuit board) 20 facing each other, and bumps 32 respectively disposed on surfaces of the semiconductor wafer 10 and the substrate 20 facing each other. And an adhesive 40 for a semiconductor filled in the gap between the semiconductor wafer 10 and the substrate 20 without a gap. The semiconductor wafer 10 and the substrate 20 are connected to each other by opposing bumps 32 and are connected via flip chip. The bump 32 is sealed by the semiconductor adhesive 40 and is blocked from the external environment.

FIGS. 2( a) and 2 (b) are schematic cross-sectional views showing another embodiment of the semiconductor device (a COC-type connection state of semiconductor wafers). As shown in FIG. 2( a ), the third semiconductor device 300 is the same as the first semiconductor device 100 except that the two semiconductor wafers 10 are flip-chip connected by the wiring 15 and the connection bump 30. As shown in FIG. 2( b ), the fourth semiconductor device 400 is the same as the second semiconductor device 200 except that the bumps 32 flip-chip connect the two semiconductor wafers 10.

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

The substrate 20 is not particularly limited as long as it is a printed circuit board, and can be used for glass epoxy resin, polyimide resin, polyester resin, ceramics, epoxy resin, bismaleimide triazine resin A circuit board on which a wiring (wiring pattern) is formed by etching away unnecessary portions of the formed metal layer on the surface of an insulating substrate as a main component; the surface of the insulating substrate is formed by metal plating or the like A circuit board on which wiring (wiring pattern) is formed; a circuit board on which wiring (wiring pattern) is formed by printing a conductive substance on the surface of the insulating substrate.

The connection parts such as the wiring 15 and the bump 32 contain gold, silver, copper, solder (main components such as tin-silver, tin-lead, tin-bismuth, tin-copper), nickel, tin, lead, etc. as main components. May contain multiple metals.

On the surface of the wiring (wiring pattern), gold, silver, copper, solder (main components such as tin-silver, tin-lead, tin-bismuth, tin-copper), tin, nickel, etc. may also be formed as the main Composition of metal layer. The metal layer may include only a single component or multiple components. In addition, it may have a structure in which a plurality of metals are laminated. Copper and solder are usually used because of their low cost. Furthermore, copper and solder contain oxides, impurities, etc., so the adhesive for semiconductors preferably has fluxing activity.

As the material of the conductive bumps called bumps, gold, silver, copper, solder (main components such as tin-silver, tin-lead, tin-bismuth, tin-copper), tin, nickel, etc. can be used as main Ingredients may include only a single ingredient or multiple ingredients. In addition, it may be formed in such a structure that these metals are laminated. The bumps can also be formed on the semiconductor wafer or the substrate. Copper and solder are usually used because of their low cost. Furthermore, copper and solder contain oxides, impurities, etc., so the adhesive for semiconductors preferably has fluxing activity.

In addition, semiconductor devices (packages) such as those shown in FIG. 1(a), FIG. 1(b) or FIGS. 2(a) and 2(b) may be laminated, and gold, silver, copper, solder (main The components are, for example, tin-silver, tin-lead, tin-bismuth, tin-copper), tin, nickel, etc., and are electrically connected. For example, as seen in TSV technology, an adhesive may be interposed between semiconductor wafers for flip-chip connection or lamination to form holes through the semiconductor wafer and be connected to electrodes on the pattern surface.

3 is a schematic cross-sectional view showing another embodiment of the semiconductor device (semiconductor wafer build-up type (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 wafer 10 via the connection bump 30, thereby connecting the semiconductor wafer 10 to the interposer 50 flip chip connection. The gap between the semiconductor wafer 10 and the interposer 50 is filled with a semiconductor adhesive 40 without a gap. On the surface of the semiconductor wafer 10 opposite to the interposer 50, the semiconductor wafer 10 is overlaid via the wiring 15, the connection bump 30 and the semiconductor adhesive 40. The wiring 15 on the pattern surface of the front and back of the semiconductor wafer 10 is connected to each other by the through electrode 34 filled in the hole penetrating the inside of the semiconductor wafer 10. In addition, as the material of the through electrode 34, copper, aluminum, or the like can be used.

With this TSV technology, signals can also be obtained from the backside of semiconductor chips that are not normally used. Furthermore, since the through-electrode 34 is vertically penetrated in the semiconductor wafer 10, the distance between the opposing semiconductor wafers 10 or between the semiconductor wafer 10 and the interposer 50 can be shortened to realize flexible connection. The adhesive for semiconductors of this embodiment can be preferably used as a sealing material between opposing semiconductor wafers 10 or between the semiconductor wafer 10 and the interposer 50 in this TSV technique.

<Method of manufacturing semiconductor device>
The manufacturing method of the semiconductor device of this embodiment uses the semiconductor adhesive of this embodiment to connect a semiconductor wafer and a printed circuit board, or a plurality of semiconductor wafers to each other. The manufacturing method of the semiconductor device of the present embodiment includes, for example, the steps of obtaining the semiconductor device by electrically connecting the connection portions of the semiconductor wafer and the wiring circuit board to each other while connecting the semiconductor wafer and the wiring circuit board via an adhesive, Or a step of obtaining a semiconductor device by electrically connecting the connection portions of the plurality of semiconductor wafers to each other while connecting the plurality of semiconductor wafers to each other via an adhesive.

In the method of manufacturing the semiconductor device of this embodiment, the connection portions can be connected to each other by metal bonding. That is, the connection portions of the semiconductor wafer and the printed circuit board are connected to each other by metal bonding, or the connection portions of the plurality of semiconductor chips are connected to each other by metal bonding.

As an example of the method of manufacturing the semiconductor device of this embodiment, a method of manufacturing the sixth semiconductor device 600 shown in FIG. 4 will be described. In the sixth semiconductor device 600, a substrate (for example, glass epoxy substrate) 60 having wiring (copper wiring) 15 and wiring (for example, pillars and copper posts) having wiring (copper wiring) 15 are connected via an adhesive 40 for semiconductor The 15 semiconductor wafers 10 are connected to each other. The wiring 15 of the semiconductor wafer 10 and the wiring 15 of the substrate 60 are electrically connected by connecting bumps (solder bumps) 30. On the surface of the substrate 60 on which the wiring 15 is formed, a solder resist 70 is arranged outside the formation position of the connection bump 30.

In the manufacturing method of the sixth semiconductor device 600, first, a semiconductor adhesive (film-like adhesive) 40 is attached to the substrate 60 on which the solder resist 70 is formed. The attachment can be performed by heat pressing, roll lamination, vacuum lamination, and the like. The supply area and thickness of the semiconductor adhesive 40 can be appropriately set according to the size of the semiconductor wafer 10 or the substrate 60, the height of the bump, and the like. The adhesive 40 for semiconductors can be attached to the semiconductor wafer 10, or the adhesive 40 for semiconductors can be attached to the semiconductor wafer and then cut into individual semiconductor wafers 10, thereby producing an adhesive with semiconductor attached 40's semiconductor wafer 10. In this case, if it is a semiconductor adhesive with high light transmittance, the visibility can be ensured even if the alignment mark is covered, so it is pasted not only on the semiconductor wafer (semiconductor wafer) but also on the substrate The scope of attachment is not limited, and the operability is excellent.

After attaching the semiconductor adhesive 40 to the substrate 60 or the semiconductor wafer 10, the connection bump 30 on the wiring 15 of the semiconductor wafer 10 and the wiring 15 of the substrate 60 are aligned using a connection device such as a flip chip bonding machine. Then, the semiconductor wafer 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 in the connection portion, it is preferable to apply a temperature of 240° C. or higher to the solder portion), thereby The semiconductor wafer 10 and the substrate 60 are connected, and the gap between the semiconductor wafer 10 and the substrate 60 is sealed and filled with the adhesive 40 for semiconductor. The connection load depends on the number of bumps, but it should be set by considering the uneven height of the absorption bumps and controlling the deformation of the bumps. From the viewpoint of improving productivity, the connection time is preferably short. Preferably, the solder is melted to remove the oxide film, impurities on the surface, and the like, and metal bonding is formed at the connection portion.

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

It is also possible to temporarily fix it after the alignment and perform heat treatment in a reflow furnace, thereby melting the solder bumps and connecting the semiconductor wafer to the substrate, thereby manufacturing a semiconductor device. Temporary fixation does not significantly require the formation of metal joints, so compared with the above-mentioned formal crimping, it can have advantages of low load, short time, and low temperature, resulting in improved productivity and prevention of deterioration of the connection part. After the semiconductor wafer and the substrate are connected, heat treatment may be performed in an oven or the like to harden the adhesive. The heating temperature is a temperature at which the adhesive is cured, preferably substantially completely cured. The heating temperature and heating time may be set appropriately. In this case, the obtained semiconductor device includes the hardened material of the adhesive.
[Example]

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

The compounds used in the examples and comparative examples are as follows.
(A) Epoxy resin and multifunctional solid epoxy resin containing triphenol methane skeleton (manufactured by Mitsubishi Chemical Corporation, trade name "EP1032H60", hereinafter referred to as "EP1032")
・Epoxy resin containing naphthalene skeleton (manufactured by DIC Corporation, trade name "HP4032D")
・Bisphenol F liquid epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name "YL983U", hereinafter referred to as "YL983")
・Soft epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name "YL7175", hereinafter referred to as "YL7175")

(B) Hardener・2,4-Diamino-6-[2'-methylimidazole-(1')]-ethyl-s-triazine isocyanurate adduct (Shikoku Chemical Industry Co., Ltd. Made by Co., Ltd. under the trade name "2MAOK-PW", hereinafter referred to as "2MAOK-PW")

(C) High-molecular-weight components with a weight average molecular weight of 10,000 or more • Acrylic resin (manufactured by Kuraray Co., Ltd., trade name "Kurarity LA4285", Mw/Mn=1.28, weight average molecular weight Mw: 80,000 )

(D) Filler inorganic filler/epoxide surface treatment nano silica filler (made by Admatechs Co., Ltd., trade name "50nmSE-AH1", average particle size: about 50 nm, hereinafter referred to as " SE Nanosilica")
・Inorganic silica filler (made by Admatechs Co., Ltd., trade name "SE2050", average particle size: 0.5 μm, hereinafter referred to as "SE2050")
・Inorganic silica filler (made by Admatechs Co., Ltd., trade name "SE2050SEJ", average particle size: 0.5 μm, hereinafter referred to as "SE2050SEJ")

(E) Flux and glutaric acid (manufactured by Sigma Aldrich, Japan, melting point: about 97°C)

<Preparation of film adhesive>
(Example 1)
11.25 g epoxy resin (6.8 g for "EP1032", 0.75 g for "HP4032D", 1.5 g for "YL983", 2.2 g for "YL7175"), 0.6 g for hardener "2MAOK", 0.45 g for glutaric acid , 35.3 g of inorganic filler "SE Nanosilica", 2.0 g of acrylic resin "LA4285", and cyclohexanone (the amount of solid content in the resin varnish is 47% by mass), the same quality as the solid content is added The beads with a diameter of 1.0 mm were stirred for 30 minutes using a bead mill (manufactured by Fritsch Co., Ltd., planetary micro-pulverizer P-7). Thereafter, the beads used for stirring are removed by filtration to obtain a resin varnish.

Apply the obtained resin varnish to a base film (made by Teijin DuPont Film Co., Ltd., trade name "Purex (Purex) A54") using a small precision coating device (manufactured by Lianjing Seiki Co., Ltd.) , Dry the applied resin varnish in a clean oven (manufactured by ESPEC) (100°C/5 minutes) to obtain a film-like adhesive. Manufactured so that the thickness becomes 0.02 mm.

(Example 2)
Except that the epoxy resin "HP4032D" was increased to 1.5 g and the epoxy resin "YL983" was reduced to 0.75 g, a film-like adhesive was produced in the same manner as in Example 1.

(Comparative example 1)
Do not mix epoxy resin "YL7175" and "HP4032D", and add inorganic silica filler (made by Admatechs Co., Ltd., trade name "SE2050", average particle size: 0.5 μm) 2.3 g, except for this Other than that, it carried out similarly to Example 1, and produced the film-like adhesive agent.

(Comparative example 2)
Adding inorganic silica filler (manufactured by Admatechs Co., Ltd., trade name "SE2050SEJ", average particle size: 0.5 μm) 3.3 g to reduce "SE nanosilica" to 27.9 g, and Except that "LA4285" was reduced to 0.5 g, a film-like adhesive was produced in the same manner as in Example 1.

Table 1 collectively shows the formulations of Examples 1 to 2 and Comparative Examples 1 to 2.

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

(1) Preparation of samples for measurement of thixotropy value Using a desktop laminator (made by Lami Corporation, trade name "HOTDOG GK-13DX"), the produced film-like adhesive was laminated ( Multilayer) until the total thickness becomes 0.4 mm (400 μm), and cut out 7.3 mm in length and 7.3 mm in width to obtain a measurement sample.

(2) Measurement of thixotropic value For the obtained measurement sample, using a shear viscosity measuring device (manufactured by TA Instruments Japan Co., Ltd., trade name "ARES") under a fixed condition of temperature 120°C Measure the viscosity at a frequency that continuously changes from 1 Hz at 0.1 Hz per second to 70 Hz, and divide the viscosity value at 7 Hz by the viscosity value at 70 Hz as the thixotropic value.

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

(4) Coverage evaluation method Observe and measure the semiconductor device obtained by the above (3) semiconductor device manufacturing method from above the upper wafer using a microscope (manufactured by Keyence Co., Ltd.) The bleed width of resin from the end of the wafer. Regarding the oozing width, the oozing width W ₁ (unit: μm) of the resin from the center of one side of the wafer, and the oozing width of the resin from the center side which is 0.2 mm from one end (the corner of the wafer) of the one side are measured W ₂ (unit: μm), and find the ratio (W ₂ /W ₁ ). In addition, W ₂ is the smaller of the oozing width of the resin from the center side 0.2 mm from one end of the one side of the wafer, and the oozing width of the resin from the center side 0.2 mm from the other end Value. The above ratio (W ₂ /W ₁ ) was measured on all four sides of the wafer, and the average value was obtained as "coverage".

Coverage is an index indicating whether the adhesive resin has penetrated the corners of the wafer in the semiconductor device. Since it is preferable that there is no difference in the bleeding width between the corners of the semiconductor device and the center of the side, the closer the coverage is to 1, the better.

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

[Table 1]

According to the evaluation results in Table 1, the coverage of Example 1 and Example 2 with a thixotropic value of 3.1 or less exceeded 0.4, and the coverage of Comparative Example 1 and Comparative Example 2 with a large thixotropic value of over 3.1 was less than 0.4. From the foregoing, it was confirmed that the film-like semiconductor adhesive of the present disclosure having a low thixotropy value has high coverage.

10‧‧‧Semiconductor chip

15‧‧‧Wiring

20, 60‧‧‧ substrate

30‧‧‧Connecting bump

32‧‧‧Bump

34‧‧‧Through electrode

40‧‧‧adhesive for semiconductor

50‧‧‧Intermediary

70‧‧‧ solder resist

100‧‧‧Semiconductor device

200‧‧‧Semiconductor device

300‧‧‧Semiconductor device

400‧‧‧Semiconductor device

500‧‧‧Semiconductor device

600‧‧‧Semiconductor device

1(a) and 1(b) are schematic cross-sectional views showing an embodiment of the semiconductor device of the present disclosure.

2(a) and 2(b) are schematic cross-sectional views showing another embodiment of the semiconductor device of the present disclosure.

3 is a schematic cross-sectional view showing another embodiment of the semiconductor device of the present disclosure.

4 is a schematic cross-sectional view showing another embodiment of the semiconductor device of the present disclosure.

Claims (8)

An adhesive for semiconductors, which is electrically connected to a semiconductor device in which the electrodes of the connection portions of the semiconductor wafer and the printed circuit board are electrically connected to each other, or the electrodes of the connection portions of the plurality of semiconductor wafers are mutually electrically In a semiconductor device formed by sexual connection, for sealing at least a part of the connection portion, The thixotropic value of the adhesive for semiconductors is 1.0 or more and 3.1 or less, The thixotropic value is a sample obtained by stacking the adhesive for semiconductors up to a thickness of 400 μm, and is measured under a fixed condition at a temperature of 120° C. using a shear viscosity measuring device to continuously change the frequency from 1 Hz to 70 Viscosity at Hz, and the value obtained by dividing the viscosity value at 7 Hz by the viscosity value at 70 Hz. The adhesive for semiconductors as described in item 1 of the patent application range 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 adhesive for semiconductor as described in item 2 of the scope of patent application further contains (d) filler. The adhesive for semiconductor as described in item 2 or 3 of the patent application scope further contains (e) flux. The adhesive for semiconductors according to any one of claims 2 to 4, wherein (c) 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 adhesive for semiconductors according to any one of claims 2 to 5 in the patent application range, wherein part or all of the material contained in the adhesive for semiconductors is soluble in cyclohexanone. The adhesive for semiconductors described in any one of the first to sixth patent application ranges is in the form of a film. A method of manufacturing a semiconductor device, including: While using the adhesive for semiconductors described in any one of the first to seventh patent application scopes, the semiconductor wafer and the printed circuit board are aligned and connected to each other while using the connection device and via the semiconductor adhesive A step of electrically connecting the electrodes of the connection portions of the semiconductor wafer and the printed circuit board to each other, and sealing at least a part of the connection portion with the adhesive for the semiconductor; or using the connection device and via the semiconductor The adhesive aligns and connects the plurality of semiconductor wafers, electrically connects the electrodes of the connection portions of the plurality of semiconductor wafers to each other, and seals at least a part of the connection portions with the semiconductor adhesive A step of.