JP6575058B2 - Bump forming material, bump forming method and semiconductor device - Google Patents

Description

  The present invention relates to a bump forming material, a bump forming method, and a semiconductor device, for example, a bump forming material for forming a fine bump on an electrode provided on a substrate, a wafer, a chip, or the like. The present invention relates to a method and a semiconductor device.

  In recent years, regarding the mounting of electronic components on a substrate, there has been an increasing demand for higher density, and face-down mounting in which electronic components are joined via metal bumps has been widely adopted as a method that satisfies such requirements.

  In face-down mounting, electronic components can be connected with low resistance, but when the electrodes of electronic components are provided at a fine pitch, metal bumps are accurately formed on the electrodes at a fine pitch. Is required. In addition, in order to obtain stable connection reliability between electronic components, it is also required to ensure the height of the metal bumps with a certain degree of accuracy and to reduce manufacturing costs.

  Metal bump formation methods for face-down mounting include plating methods and vapor deposition methods, but these methods require significant capital investment and long manufacturing processes, and control bump height. And problems such as difficulty in forming fine bumps.

  Here, with reference to FIG.3 and FIG.4, the conventional bump formation process by a vapor deposition method is demonstrated. First, as shown in FIG. 3A, a resist 33 is applied to the surface of the semiconductor integrated circuit chip 30 having the pads 32 formed on the outermost surface. In the figure, reference numeral 31 denotes a coating insulating film. Next, as shown in FIG. 3B, the bump formation portion is selectively exposed and developed to form an opening 34 having an inversely tapered side wall to form a lift-off mask.

  Next, as shown in FIG. 3C, a metal film 35 for pad formation is formed by vapor deposition. Next, as shown in FIG. 4D, the metal film deposited on the resist 33 is also lifted off by removing the resist 33, and the remaining metal film is used as a bump forming metal film 36.

  Next, as shown in FIG. 4E, a flux 37 is applied to the entire surface. Next, as shown in FIG. 4 (f), the bump forming metal film 36 is reflowed to form bumps 38 by heating. Next, as shown in FIG. 4G, by removing the flux 37, a semiconductor integrated circuit chip on which the bumps 38 are formed is obtained.

  However, the bump forming method using the lift-off method is difficult to meet the demand for miniaturization because it is difficult to form openings in the lift-off mask with high density. Also, the height of the bump depends on the size of the opening and the thickness of the deposited metal film, but it is difficult to control both with high accuracy. Difficult to do.

  Therefore, various methods have been proposed as methods for selectively forming a conductor on a substrate with high accuracy other than the conventional plating method and vapor deposition method (see, for example, Patent Documents 2 to 4). In these proposals, a metal wiring is formed by forming a film containing metal, selectively irradiating with radiation, and removing a non-irradiated portion.

JP 2004-079771 A JP 10-508660 gazette JP 2008-159754 A JP 2009-004669 A

  However, in Patent Document 2, a metal complex is used, and in Patent Document 3 or Patent Document 4, a dispersion of metal fine particles is used. Therefore, there is a problem that baking at a high temperature is indispensable, and formation of a high aspect pattern such as a bump is difficult due to low resolution.

  Accordingly, it is an object to form bumps with high accuracy, low cost and high reliability by low-temperature firing.

From one disclosed aspect, there is provided a bump forming material including at least metal fine particles having an average particle diameter of 2 nm to 100 nm, a base resin, a photoacid generator, a crosslinking agent, and a solvent.

From another viewpoint to be disclosed, a bump-forming material film is formed on a substrate using the above-described bump-forming material, and the bump-forming material film is selectively irradiated with ionizing radiation to form the bump. the use material coating and developing treatment remains the irradiated portion of the ionizing radiation of the bump forming material film, a bump forming method and firing the bump forming material coating is provided.

  From another viewpoint to be disclosed, a semiconductor device including a bump formed by the above-described bump forming method is provided.

  According to the disclosed bump forming material, bump forming method, and semiconductor device, the bump can be formed with high accuracy, low cost, and high reliability by low-temperature firing.

It is explanatory drawing of the bump formation method of embodiment of this invention. It is explanatory drawing of the bump formation method of Example 1 of this invention. It is explanatory drawing to the middle of the bump formation process by the conventional vapor deposition method. It is explanatory drawing after FIG. 3 of the bump formation process by the conventional vapor deposition method.

  Here, with reference to FIG. 1, the bump formation method of embodiment of this invention is demonstrated. FIG. 1 is an explanatory diagram of a bump forming method according to an embodiment of the present invention. First, as shown in FIG. 1 (a), a bump forming material film containing at least metal fine particles, a base resin, a photoacid generator, a crosslinking agent, and a solvent on a substrate 11 having an electrode 12 formed on the surface thereof. 13 is applied and baked to remove the solvent in the bump forming material 13. Next, as shown in FIG. 1B, the bump-forming material film 13 is selectively irradiated with ionizing radiation 14 to ionize the photoacid generator at the irradiated portion to generate an acid, and heat treatment is performed. This promotes the crosslinking reaction between the base resin and the crosslinking agent.

  Next, as shown in FIG. 1C, the bump forming material film 13 in the unirradiated portion is removed by developing with a developing solution, and the irradiated portion is left as a bump forming pattern 15. Next, as shown in FIG. 1D, the bumps 16 are formed by firing at a low temperature to reduce the organic components. In the embodiment of the present invention, since a resist mask is not required only by the exposure process, it is possible to form a bump having a fine pitch and excellent height accuracy. In addition, since the metal complex or metal particles are not used directly, the heat treatment may be performed even at a low temperature at which the base resin does not undergo modification, which simplifies the manufacturing process.

  The method for applying the bump forming material in this case is not particularly limited, and can be appropriately selected from known application methods according to the purpose. Examples include dip coating, spin coating, spray coating, vapor coating, various printing methods, doctor blade methods, and the like. However, the spray coating method is particularly desirable for handling bump forming materials containing metal fine particles. Utilizing this spray coating method, the composition can be controlled in the film thickness direction by preparing multiple nozzles and spraying bump forming materials with different contents of various components onto the substrate at an arbitrary ratio. Is also possible.

  The ionizing radiation is not particularly limited as long as it can generate an acid by ionizing a photoacid generator, and can be appropriately selected according to the purpose. Examples thereof include ultraviolet rays, X-rays, electron beams, excimers. It is desirable to use an active energy beam such as a laser beam or a focused ion beam. In particular, X-rays or electron beams that are not easily affected by shielding by metal fine particles contained in the coating are desirable.

  Gold, platinum, copper, silver, indium, cobalt, nickel, bismuth, tin, rhodium, palladium, iridium, tungsten, aluminum, chromium, titanium, zinc, etc. can be selected as necessary as the metal fine particles. is there. It is also possible to use an alloy of these metals or a mixture of single metal fine particles.

  The average particle size of the metal fine particles is preferably 1 nm to 500 nm, and more preferably 2 nm to 100 nm. If the average particle size exceeds 500 nm, it is difficult to form a uniform film, and if it is less than 1 nm, it is difficult to maintain a bump forming pattern using a base resin.

  As the base resin, polyvinyl alcohol, polyvinyl acetal, polyvinyl acetate, polyvinyl pyrrolidone, polyacrylic acid, polyethylene oxide, phenolic hydroxyl group-containing resin, carboxyl group-containing resin, epoxy resin and the like can be selected as necessary. . Moreover, it is also possible to use these as a copolymer and a mixture.

  In the bump forming material, it is desirable that the metal fine particles are contained in an amount of 25 wt% to 400 wt% with respect to the base resin. When the content is less than 25% by weight, it is difficult to ensure conductivity, and when it exceeds 400% by weight, the crosslinking reaction does not proceed sufficiently, and a pattern may not be formed.

The photoacid generator is not particularly limited as long as it is a material that generates acid upon irradiation with ionizing radiation, and a group of iodonium salts represented by the following general formula can be used.

Alternatively, a group of sulfonium salts represented by the following general formula can be used.

Alternatively, a group of halogen compounds represented by the following general formula can be used.

Alternatively, a group of sulfonate compounds represented by the following general formula can be used.

Alternatively, a group of imide compounds represented by the following general formula can be used.

Alternatively, a group of carbonyl compounds represented by the following general formula can be used.

Alternatively, disulfone represented by the following general formula can be used.

Alternatively, a group of α, α-bisallylsulfonyldiazomethane represented by the following general formula can be used.

Furthermore, a group of diazonium salts represented by the following general formula can be used.

  As content of a photo-acid generator, it is desirable that it is 0.5 to 30 weight% with respect to base-material resin. If the content is less than 0.5% by weight, the cross-linking reaction of the base resin may not proceed sufficiently. If the content exceeds 30% by weight, the cross-linking reaction may reach the unexposed area.

  The cross-linking agent is not particularly limited as long as it has a function of cross-linking the base resin, and can be appropriately selected according to the purpose. For example, an amino type crosslinking agent is mentioned. Preferred examples of the amino crosslinking agent include urea derivatives, melamine derivatives, uril derivatives, and the like. These may be used individually by 1 type and may use 2 or more types together.

  Among these, examples of urea derivatives include urea, alkoxymethylene urea, N-alkoxymethylene urea, ethylene urea, ethylene urea carboxylic acid, and derivatives thereof. Moreover, as a melamine derivative, alkoxymethylmelamine, these derivatives, etc. are mentioned, for example. Examples of the uril derivative include benzoguanamine, glycoluril, and derivatives thereof.

  The content of the crosslinking agent is preferably 0.5% by weight to 50% by weight, and more preferably 1% by weight to 40% by weight with respect to the content of the base resin. If the content is less than 0.5% by weight, the crosslinking reaction to the base resin may not proceed sufficiently, and if it exceeds 50% by weight, the crosslinking reaction may reach the unexposed area.

  The solvent is not particularly limited as long as it can dissolve each component of the bump forming material, has an appropriate drying speed, and can form a uniform and smooth coating film after the organic solvent evaporates. What is normally used in the said technical field can be used. Examples of such solvents include glycol ether esters, glycol ethers, esters, ketones, cyclic esters, alcohols and water.

  Among these, examples of glycol ether esters include ethyl cellosolve acetate, methyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate and the like. Examples of ethers include ethyl cellosolve, methyl cellosolve, propylene glycol monomethyl ether, and propylene glycol monoethyl ether. Examples of the esters include ethyl lactate, butyl acetate, amyl acetate, and ethyl pyruvate. Examples of ketones include 2-heptanone and cyclohexanone. Examples of cyclic esters include γ-butyrolactone. Examples of alcohols include methanol, ethanol, propanol, isopropanol, butanol and the like. These solvents may be used alone or in combination of two or more.

  Further, as other components, as long as the effects of the present invention are not adversely affected, they can be appropriately selected according to the purpose, and include various known additives. For example, the solubility and applicability of each of the above compositions For the purpose of improvement, isopropyl alcohol, a surfactant and the like can be added.

  Such a surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. Nonionic surfactants, cationic surfactants, anionic surfactants, amphoteric surfactants, etc. Is mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, nonionic surfactants are desirable in that they do not contain metal ions.

  Examples of such nonionic surfactants include those selected from alkoxylate surfactants, fatty acid ester surfactants, amide surfactants, alcohol surfactants, and ethylenediamine surfactants. Preferably mentioned. Specific examples of these include polyoxyethylene-polyoxypropylene condensate compounds, polyoxyalkylene alkyl ether compounds, polyoxyethylene alkyl ether compounds, polyoxyethylene derivative compounds, sorbitan fatty acid ester compounds, glycerin fatty acid ester compounds, Primary alcohol ethoxylate compound, phenol ethoxylate compound, nonylphenol ethoxylate, octylphenol ethoxylate, lauryl alcohol ethoxylate, oleyl alcohol ethoxylate, fatty acid ester, amide, natural alcohol, ethylenediamine, Secondary alcohol ethoxylate type and the like.

  Moreover, there is no restriction | limiting in particular as a cationic surfactant, According to the objective, it can select suitably, For example, an alkyl cation type surfactant, an amide type quaternary cationic surfactant, an ester type quaternary cation And surface active agents.

  The amphoteric surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include amine oxide surfactants and betaine surfactants. The content of these surfactants in the bump forming material can be appropriately determined according to the type and content of each component.

  Further, in order to prevent oxidation of the metal fine particles contained in the bump forming material, a reducing agent represented by carboxylic acid or the like may be added to the bump forming material. Such a carboxylic acid is not particularly limited as long as it is a material species having a reducing action, but an acrylic acid derivative, acetic acid, oxalic acid or formic acid is preferable, and an acrylic acid derivative is particularly desirable. In addition, a material having a reducing action such as aldehyde can be used as necessary.

  The content of the carboxylic acid is preferably in the range of 0.1% by weight to 40% by weight with respect to the metal fine particles. When the content is less than 0.1% by weight, the carboxylic acid does not spread sufficiently in the film, and the function as a reducing agent is impaired. On the other hand, if the content exceeds 40% by weight, the reaction between the base resin and the crosslinking agent may be affected.

  Moreover, there is no restriction | limiting in particular as a developing solution used by image development processing, Although it can select suitably according to the objective, Water or aqueous alkali solution is especially suitable and can reduce the burden on an environment. Examples of the alkali include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium silicate and ammonia; primary amines such as ethylamine and propylamine; secondary amines such as diethylamine and dipropylamine; trimethylamine and triethylamine Tertiary amines; Alcohol amines such as diethylethanolamine and triethanolamine; Quaternary ammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, triethylhydroxymethylammonium hydroxide, and trimethylhydroxyethylammonium It is done.

  If necessary, a water-soluble organic solvent such as methyl alcohol, ethyl alcohol, propyl alcohol, and ethylene glycol, a surfactant, a resin dissolution inhibitor, and the like can be added to the alkaline aqueous solution. What is necessary is just to use what is added to the material for bump formation as surfactant added to alkaline aqueous solution.

  According to the bump forming method of the embodiment of the present invention, there is no pattern loss or dimension variation, and a bump forming pattern can be easily and efficiently formed at a low cost with high resolution. Furthermore, it can also be used to form various conductive patterns other than bumps, such as line & space patterns, hole patterns, pillar (column) patterns, trench (groove) patterns, line patterns, and the like. Further, examples of the substrate to be subjected to the bump formation include a mounting wiring substrate, a semiconductor chip, and a semiconductor wafer.

Next, with reference to FIG. 2, a bump forming method according to the first embodiment of the present invention will be described. First, the following substances are prepared as a bump forming material and mixed to obtain a bump forming material.
Metal fine particles: Indium (A-1) having an average particle diameter of 20 nm 200 parts by weight Base resin: 30% acetalized polyvinyl alcohol (B-1) 100 parts by weight Crosslinking agent: Tetramethoxymethylglycoluril (C-1) 20 Part by weight Photoacid generator: Bis (cyclohexylsulfonyl) diazomethane (D-1) 10 parts by weight Reducing agent: Polyacrylic acid (E-1) 5 parts by weight Solvent: Propylene glycol propyl ether (F-1) 1400 parts by weight

  Next, as shown in FIG. 2A, a bump forming material is sprayed by a spray coater onto a semiconductor substrate 21 in which 5 μm □ pads 22 are arranged vertically and horizontally at a pitch of 10 μm, and then deposited at 90 ° C. Baking is performed to form a bump-forming material film 23. Here, the thickness of the bump-forming material film 23 was set to 3 μm by adjusting the spray pressure and time.

  Next, as shown in FIG. 2B, an electron beam 24 having an acceleration voltage of 50 kV was drawn in a 5 μm square pattern at a location corresponding to the pad 22 using an electron beam exposure machine. Next, as shown in FIG. 2 (c), after drawing, baking is performed at 100 ° C., development is performed with a 4% aqueous potassium hydroxide solution for 60 seconds, and unirradiated portions are removed to form a bump forming pattern. 25 is formed. Finally, as shown in FIG. 2D, the semiconductor substrate 21 on which the bump forming pattern 25 is formed is heated in a nitrogen atmosphere at 200 ° C. for 5 minutes to form bumps 26.

  As a result, by using the bump forming material having the above-described composition, it was possible to form bumps with a fine pitch of 10 μm, which cannot be achieved by the conventional method, within a height variation of 0.2 μm.

Next, the bump forming method of Example 2 of the present invention will be described. However, the weight ratio of other compositions and the manufacturing method are exactly the same as those of Example 1 except that the solvent is different. Only the composition of will be described. In Example 2 of the present invention, the following substances were prepared as the bump forming material and mixed to obtain a bump forming material.
Metal fine particles: Indium (A-1) having an average particle diameter of 20 nm 200 parts by weight Base resin: 30% acetalized polyvinyl alcohol (B-1) 100 parts by weight Crosslinking agent: Tetramethoxymethylglycoluril (C-1) 20 Parts by weight photoacid generator: bis (cyclohexylsulfonyl) diazomethane (D-1) 10 parts by weight reducing agent: polyacrylic acid (E-1) 5 parts by weight solvent: isopropyl alcohol (F-2) 600 parts by weight

  In Example 2 as well, by using the bump forming material having the above-described composition, it was possible to form bumps with a fine pitch of 10 μm, which cannot be achieved by the conventional method, within a height variation of 0.2 μm.

Next, the bump forming method of Example 3 of the present invention will be described. However, the weight ratio of other compositions and the manufacturing method are exactly the same as those of Example 1 described above, only by reducing the weight part of the metal fine particles. Only the composition of the bump forming material will be described. In Example 3 of the present invention, the following substances were prepared as the bump forming material and mixed to obtain a bump forming material.
Metal fine particles: Indium (A-1) having an average particle diameter of 20 nm 25 parts by weight Base resin: 30% acetalized polyvinyl alcohol (B-1) 100 parts by weight Crosslinking agent: Tetramethoxymethylglycoluril (C-1) 20 Part by weight Photoacid generator: Bis (cyclohexylsulfonyl) diazomethane (D-1) 10 parts by weight Reducing agent: Polyacrylic acid (E-1) 5 parts by weight Solvent: Propylene glycol propyl ether (F-1) 1400 parts by weight

  Also in this Example 3, by using the bump forming material having the above-described composition, similarly to Example 1, a 10 μm fine pitch bump, which cannot be achieved by the conventional method, is formed within a height variation of 0.2 μm. We were able to.

Next, the bump forming method of Example 4 of the present invention will be described. However, the weight ratio of other compositions and the manufacturing method are exactly the same as in Example 2 above, except that the solvent is changed. Only the composition of the material will be described. In Example 4 of the present invention, the following substances were prepared as a bump forming material and mixed to obtain a bump forming material.
Metal fine particles: Indium (A-1) having an average particle diameter of 20 nm 25 parts by weight Base resin: 30% acetalized polyvinyl alcohol (B-1) 100 parts by weight Crosslinking agent: Hexamethoxymethylmelamine (C-2) 20 parts by weight Part photoacid generator: bis (cyclohexylsulfonyl) diazomethane (D-1) 10 parts by weight reducing agent: polyacrylic acid (E-1) 5 parts by weight solvent: isopropyl alcohol (F-2) 600 parts by weight

  Also in Example 4, by using the bump forming material having the above-described composition, as in Example 2, bumps with a fine pitch of 10 μm, which cannot be achieved by the conventional method, are formed within a height variation of 0.2 μm. We were able to.

Next, the bump forming method of Example 5 of the present invention will be described. However, the weight ratio of other compositions and the manufacturing method are exactly the same as those of Example 1 described above just by increasing the weight part of the metal fine particles. Only the composition of the bump forming material will be described. In Example 5 of the present invention, the following substances were prepared as the bump forming material and mixed to obtain a bump forming material.
Metal fine particles: Indium (A-1) having an average particle diameter of 20 nm 400 parts by weight Base resin: 30% acetalized polyvinyl alcohol (B-1) 100 parts by weight Crosslinking agent: Tetramethoxymethylglycoluril (C-1) 20 Part by weight Photoacid generator: Bis (cyclohexylsulfonyl) diazomethane (D-1) 10 parts by weight Reducing agent: Polyacrylic acid (E-1) 5 parts by weight Solvent: Propylene glycol propyl ether (F-1) 1400 parts by weight

  Also in Example 5, by using the bump forming material having the above-described composition, as in Example 1, bumps with a fine pitch of 10 μm, which cannot be achieved by the conventional method, are formed within a height variation of 0.2 μm. We were able to.

Next, the bump forming method of Example 6 of the present invention will be described. However, the weight ratio of other compositions and the manufacturing method are exactly the same as in Example 5 above, except that the solvent is changed. Only the composition of the material will be described. In Example 6 of the present invention, the following substances were prepared as the bump forming material and mixed to obtain a bump forming material.
Metal fine particles: Indium (A-1) having an average particle diameter of 20 nm 400 parts by weight Base resin: 30% acetalized polyvinyl alcohol (B-1) 100 parts by weight Crosslinking agent: Tetramethoxymethylglycoluril (C-1) 20 Parts by weight photoacid generator: bis (cyclohexylsulfonyl) diazomethane (D-1) 10 parts by weight reducing agent: polyacrylic acid (E-1) 5 parts by weight solvent: isopropyl alcohol (F-2) 600 parts by weight

  Also in the sixth embodiment, by using the bump forming material having the above-described composition, as in the second embodiment, a bump having a fine pitch of 10 μm, which cannot be achieved by the conventional method, is formed within a height variation of 0.2 μm. We were able to.

Next, the bump forming method of Example 7 of the present invention will be described, but the material of the bump forming material was changed, but the manufacturing method is exactly the same as in Example 1 above, so the composition of the bump forming material is I will explain only. In Example 7 of the present invention, the following substances were prepared as a bump forming material and mixed to obtain a bump forming material.
Metal fine particles: Tin-bismuth alloy (A-2) having an average particle diameter of 20 nm 200 parts by weight Base resin: Poly (methyl methacrylate-methacrylic acid) copolymer (50/50) (B
-2) 100 parts by weight cross-linking agent: hexamethoxymethyl melamine (C-2) 20 parts by weight photoacid generator: diphenyliodonium nonafluorobutane sulfonate (D-2)
10 parts by weight reducing agent: oxalic acid (E-2) 5 parts by weight Solvent: isopropyl alcohol (F-1) 1400 parts by weight

  In Example 7 as well, by using the bump forming material having the above-described composition, as in Example 1, bumps with a fine pitch of 10 μm, which cannot be achieved by the conventional method, are formed within a height variation of 0.2 μm. We were able to.

Next, the bump forming method of Example 8 of the present invention will be described, but the composition and manufacturing method are the same as those of Example 7 except that the solvent is different. Therefore, only the composition of the bump forming material is used. Will be explained. In Example 8 of the present invention, the following substances were prepared as a bump forming material and mixed to obtain a bump forming material.
Metal fine particles: Tin-bismuth alloy (A-2) having an average particle diameter of 20 nm 200 parts by weight Base resin: Poly (methyl methacrylate-methacrylic acid) copolymer (50/50) (B
-2) 100 parts by weight cross-linking agent: hexamethoxymethyl melamine (C-2) 20 parts by weight photoacid generator: diphenyliodonium nonafluorobutane sulfonate (D-2)
10 parts by weight reducing agent: oxalic acid (E-2) 5 parts by weight Solvent: isopropyl alcohol (F-2) 600 parts by weight

  Also in Example 8, by using the bump forming material having the above-described composition, as in Example 7, bumps with a fine pitch of 10 μm, which cannot be achieved by the conventional method, are formed within a height variation of 0.2 μm. We were able to.

Table 1 summarizes the constituent materials of each of the above examples. For comparison, Comparative Example 1 and Comparative Example 2 in which no base resin is used, Comparative Example 3 in which no cross-linking agent is added, and Comparative Example 4 and Comparative Examples 5 and 6 with no photoacid generator added are also presented.

  In the case of Comparative Example 1 and Comparative Example 2, since the base resin used as a base was not used, the crosslinking reaction did not occur, so that the bump forming pattern could not be formed. Moreover, in the case of Comparative Example 3 and Comparative Example 4, since no crosslinking agent was added, the crosslinking reaction of the base resin did not proceed, so that the bump forming pattern could not be formed. Furthermore, in the case of Comparative Example 5 and Comparative Example 6, since no photoacid generator was added, an exposure pattern could not be formed even when irradiated with an electron beam. The pattern for use could not be formed.

Here, the following additional notes are attached to the embodiment of the present invention including Examples 1 to 8.
(Appendix 1) A bump forming material comprising at least metal fine particles having an average particle diameter of 2 nm to 100 nm, a base resin, a photoacid generator, a crosslinking agent, and a solvent.
(Appendix 2) Among the metals selected from gold, platinum, copper, silver, indium, cobalt, nickel, bismuth, tin, rhodium, palladium, iridium, tungsten, aluminum, chromium, titanium, and zinc, The material for forming a bump according to appendix 1, which includes at least one of them.
(Appendix 3) Among the resins selected from the base resin, polyvinyl alcohol, polyvinyl acetal, polyvinyl acetate, polyvinyl pyrrolidone, polyacrylic acid, polyethylene oxide, phenolic hydroxyl group-containing resin, carboxyl group-containing resin, and epoxy resin, The bump forming material according to supplementary note 1 or supplementary note 2, characterized by containing at least one of them.
(Supplementary note 4) The bump forming material according to supplementary note 3, wherein the metal fine particles are contained in an amount of 25 wt% to 400 wt% with respect to the base resin.
(Supplementary Note 5) The photoacid generator is an iodonium salt, a sulfonium salt, a halogen compound, a sulfonic acid ester compound, an imide compound, a carbonyl compound, a disulfone compound, α, α-bisallylsulfonyldiazomethane, or a diazonium salt. The material for forming bumps according to any one of appendix 1 to appendix 4, characterized by containing at least one of them.
(Additional remark 6) The said crosslinking agent contains at least any one among the crosslinking agents chosen from the urea derivative, the melamine derivative, and the uril derivative, It is any one of Additional remark 1 thru | or Additional remark 5 characterized by the above-mentioned. Bump forming material.
(Supplementary note 7) The supplementary note, wherein the solvent contains at least one of water, alcohol, chain ester, cyclic ester, ketone, chain ether, and cyclic ether. The bump forming material according to any one of 1 to appendix 6.
(Appendix 8) Polyoxyethylene-polyoxypropylene condensate system, polyoxyalkylene alkyl ether system, polyoxyethylene alkyl ether system, polyoxyethylene derivative system, sorbitan fatty acid ester system, glycerin fatty acid ester system, primary alcohol ethoxy The bump formation according to any one of appendix 1 to appendix 7, further comprising a nonionic surfactant selected from a group of surfactants of rate-based, phenol ethoxylate-based, and acetylenic diol-based surfactants Materials.
(Supplementary note 9) The bump forming material according to any one of supplementary notes 1 to 8, wherein a reducing agent containing at least a carboxylic acid is further added.
(Supplementary note 10) The bump forming material according to supplementary note 9, wherein the reducing agent includes at least one of acrylic acid derivatives, acetic acid, oxalic acid, and formic acid.
(Appendix 11) A bump-forming material film is formed on the substrate using the bump-forming material described in any one of Appendices 1 to 10, and the bump-forming material film is selectively irradiated with ionizing radiation. , bump forming method, wherein the bump forming material coating and developing treatment remains the irradiated portion of the ionizing radiation of the bump forming material coating, firing the bump forming material coating.
(Additional remark 12) The said ionizing radiation is an electron beam, The bump formation method of Additional remark 11 characterized by the above-mentioned.
(Additional remark 13) The semiconductor device provided with the bump formed with the bump formation method of Additional remark 11 or Additional remark 12.

11 Substrate 12 Electrode 13 Bump Forming Material Film 14 Ionizing Radiation 15 Pump Forming Pattern 16 Bump 21 Semiconductor Substrate 22 Pad 23 Bump Forming Material Film 24 Electron Beam 25 Bump Forming Pattern 26 Bump 30 Semiconductor Integrated Circuit Chip 31 Covering Insulating Film 32 Pad 33 Resist 34 Opening 35 Metal Film 36 Metal Film 37 for Forming Pump Flux 38 Bump

Claims (6)

A bump forming material comprising at least metal fine particles having an average particle diameter of 2 nm to 100 nm, a base resin, a photoacid generator, a crosslinking agent, and a solvent.   The metal fine particles include at least one selected from gold, platinum, copper, silver, indium, cobalt, nickel, bismuth, tin, rhodium, palladium, iridium, tungsten, aluminum, chromium, titanium, and zinc. The bump forming material according to claim 1, further comprising:   The base resin is at least one selected from polyvinyl alcohol, polyvinyl acetal, polyvinyl acetate, polyvinyl pyrrolidone, polyacrylic acid, polyethylene oxide, phenolic hydroxyl group-containing resin, carboxyl group-containing resin, and epoxy resin. The bump forming material according to claim 1, comprising: a bump forming material.   The bump forming material according to claim 3, wherein the metal fine particles are contained in an amount of 25 wt% to 400 wt% with respect to the base resin. Forming a bump-forming material film on the substrate using the bump-forming material according to any one of claims 1 to 4,
Selectively irradiating the bump forming material film with ionizing radiation;
The bump-forming material film is developed to leave the portion irradiated with the ionizing radiation of the bump-forming material film,
A bump forming method comprising firing the bump forming material film.   A semiconductor device comprising a bump formed by the bump forming method according to claim 5.

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