JP2000154250A - Polyimide resin for underfill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyimide resin which is soluble in organic solvents and desirably applied to an underfill process where the circuit board on which semiconductor chips have been mounted is a polyimide substrate by selecting a polyimide resin containing a specified proportion of a polyimidosiloxane component. SOLUTION: The polyimide resin used comprises 40-80 mol% polyimidosiloxane component of formula I, 5-50 mol% polyimide component of formula II, and the balance of a polyimide component of formula III. In the formulae, R1 is a residue derived by removing the four carboxyl groups from an aromatic tetracarboxylic acid; R2 is a hydrocarbon group or phenylene; R3 is a 1-3C alkyl or phenyl; n1 is 3-50; r1 is hydroxyl or carboxyl; X is a direct bond, -O-, -S-, or a group of any one of formulae IV to IX; n2 is 1 or 2; n3 is 0-3; R4 and R5 are each H, methyl, or trifluoromethyl; and R6 is a residue derived by removing the amino groups from a diamine compound other than the diamine compounds forming the diamine components of formulae I and II.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyimide resin for underfill which is soluble in an organic solvent, an underfill material containing the resin, and a cured film formed by the underfill material. It is suitable to be applied to an underfill step in a case where a circuit board on which is mounted is a polyimide substrate.

[0002]

2. Description of the Related Art Electronic devices such as mobile phones and mobile phones are required to be light and small, and a bare semiconductor is directly mounted on a circuit board from a conventional mounting method such as a pin grid array. An implementation method has been developed. Among these methods, in the case of a semiconductor bare chip mounting by the face-down method, a gap is generated between the bare chip and the substrate, and the gap needs to be filled with a non-conductive material. This non-conductive material is called an underfill material (sealing material), and an epoxy-based underfill material has been developed.

[0003] However, as the pitch of the circuit becomes narrower, the adhesion between the circuit board and the epoxy underfill material and the occurrence of cracks after the underfill material is cured have become problems. In particular, when the circuit board is a polyimide substrate, the epoxy-based underfill material has poor wettability with the polyimide film, so that the epoxy-based underfill material is bubbled in a narrow gap between the semiconductor chip and the polyimide substrate. It is difficult to fill sufficiently without generating
In addition, since a crack occurs after curing and does not function as an insulating film, development of a new underfill material has been required.

Accordingly, an object of the present invention is to provide a polyimide film having good wettability, which can easily fill a narrow gap between a semiconductor chip and a polyimide substrate, good adhesion between the polyimide substrate and the semiconductor chip, and after curing. Cracks do not occur, and the cured film obtained has both excellent electrical properties and solder heat resistance, can prevent the occurrence of metal migration between bumps, and can reinforce semiconductor contacts.
An object of the present invention is to provide an underfill material.

[0005]

Means for Solving the Problems The present inventors have conducted various studies on the binder resin of the underfill material, and as a result,
It has been found that an underfill material that achieves the above object can be obtained by using a polyimide resin containing a specific amount of a specific polyimide siloxane component. The present invention
Based on the above findings, polyimide siloxane components 40 to 40 represented by the following general formula (1)
80 mol%, 5 to 50 mol% of a polyimide component represented by the following general formula (2) represented by the following chemical formula (2), and a remaining polyimide component represented by the following general formula (3) represented by the following chemical formula (3).
(00 mol%).

[0006]

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[0007]

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[0008]

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Further, the present invention provides the following components (a) and (b)
And (c), wherein the solution viscosity at 25 ° C. is 500 centipoise or less. (A) 100 parts by weight of the above-mentioned polyimide resin for underfill of the present invention (b) 2 to 30 parts by weight of an epoxy resin (c) 50 to 140 parts by weight of a high boiling point solvent

[0010] The present invention is also formed by filling a space between a polyimide substrate and a semiconductor chip mounted on the substrate with the above-described underfill material of the present invention, followed by heating, drying and curing. A cured film of the underfill material is provided.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The polyimide resin for underfill of the present invention, an underfill material containing the resin, and a cured film formed by the underfill material will be described in detail below.

First, the underfill polyimide resin of the present invention will be described. The polyimide resin for underfill of the present invention comprises an aromatic tetracarboxylic acid component, a diaminopolysiloxane represented by the following general formula (4) and a general formula (5) represented by the following chemical formula (8). Diamine compound and, if necessary, other diamine compound [H ₂
It can be obtained by thermally or chemically imidizing a diamine component comprising NR ₆ —NH ₂ (R ₆ is the same as in the case of the general formula (3)) in an organic solvent.

[0013]

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[0014]

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The aromatic tetracarboxylic acid component includes 2,3,3 ′, 4′-biphenyltetracarboxylic acid, 3,3 ′, 4,4′-biphenyltetracarboxylic acid, 3,3 ′, 4, 4'-diphenylethertetracarboxylic acid, 3,3 ', 4,4'-diphenylsulfonetetracarboxylic acid, 3,3', 4,4'-benzophenonetetracarboxylic acid, 2,2-bis (3,4-benzene Dicarboxylic acid) hexafluoropropane, pyromellitic acid, 1,4-bis (3,4-benzenedicarboxylic acid) benzene, 2,2-bis [4- (3,4-phenoxydicarboxylic acid) phenyl] propane, or a mixture thereof And esterified products of lower alcohols. Among these, 2,3,3 ′, 4′-biphenyltetracarboxylic acid, 3,3 ′, 4,4′-diphenylethertetracarboxylic acid, and dianhydrides of these acids are particularly suitable for the above-mentioned underfill. This is preferable because the solubility of the polyimide resin in an organic solvent is excellent.

As the diaminopolysiloxane represented by the above general formula (4), R _{2 in} the formula is a divalent hydrocarbon group,
Preferably, it is an alkylene group having 2 to 6 carbon atoms, more preferably an alkylene group having 3 to 5 carbon atoms, or a phenylene group, wherein R ₃ is independently a methyl group having 1 to 3 carbon atoms, an ethyl group,
An alkyl group such as a propyl group or a phenyl group, and n
1 is 3 to 50, preferably 3 to 20. When the number of n1 is small, the curling property tends to be high. When the number of n1 is too large, the solvent resistance is reduced, the reactivity with the aromatic tetracarboxylic acid component is reduced, and Since the molecular weight of the polyimide resin to be obtained is low, the solubility in an organic solvent is low, and the compatibility with other organic compounds is poor, the above-mentioned one is suitable.

Specific examples of the diaminopolysiloxane represented by the above general formula (4) include α, ω-bis (2-aminoethyl) polydimethylsiloxane, α, ω
-Bis (3-aminopropyl) polydimethylsiloxane, α, ω-bis (4-aminophenyl) polydimethylsiloxane, α, ω-bis (4-amino-3-methylphenyl) polydimethylsiloxane, α, ω- Screw (3-
Aminopropyl) polydiphenylsiloxane, α, ω-
Bis (4-aminobutyl) polydimethylsiloxane and the like can be mentioned.

The diamine compound represented by the general formula (5) is an aromatic diamine having a group (hydroxyl group or carboxyl group) having a reactivity with an epoxy resin in the molecule. Examples of the diamine compound having a hydroxyl group in the diamine compound represented by the general formula (5) include diaminophenol compounds such as 2,4-diaminophenol, 3,3′-diamino, 4,4′-dihydroxybiphenyl, 4 '
-Diamino, 3,3'-dihydroxybiphenyl,
Hydroxybiphenyl compounds such as 4,4′-diamino, 2,2′-dihydroxybiphenyl, 4,4′-diamino, 2,2 ′, 5,5′-tetrahydroxybiphenyl, 3,3′-diamino, 4,4'-dihydroxydiphenylmethane, 4,4'-diamino, 3,3 '
-Dihydroxydiphenylmethane, 4,4'-diamino, 2,2'-dihydroxydiphenylmethane, 2,
2-bis [3-amino, 4-hydroxyphenyl] propane, 2,2-bis [4-amino, 3-hydroxyphenyl] propane, 2,2-bis [3-amino, 4-
Hydroxyphenyl] hexafluoropropane, 4,
Hydroxydiphenylalkane compounds such as 4'-diamino, 2,2 ', 5,5'-tetrahydroxydiphenylmethane, 3,3'-diamino, 4,4'-dihydroxydiphenylether, 4,4'-diamino,
3,3′-dihydroxydiphenyl ether, 4,
4'-diamino, 2,2'-dihydroxydiphenyl ether, 4,4'-diamino, 2,2 ', 5,5'-
Hydroxydiphenylether compounds such as tetrahydroxydiphenylether, 3,3′-diamino,
4,4′-dihydroxydiphenyl sulfone, 4,
4'-diamino, 3,3'-dihydroxydiphenylsulfone, 4,4'-diamino, 2,2'-dihydroxydiphenylsulfone, 4,4'-diamino, 2,4
Hydroxydiphenylsulfone compounds such as 2 ′, 5,5′-tetrahydroxydiphenylsulfone;
Bis (hydroxyphenoxyphenyl) alkane compounds such as 2-bis [4- (4-amino, 3-hydroxyphenoxy) phenyl] propane, and 4,4′-bis (4-amino, 3-hydroxyphenoxy) biphenyl Bis (hydroxyphenoxy) biphenyl compounds, and bis (hydroxyphenoxyphenyl) sulfone compounds such as 2,2-bis [4- (4-amino, 3-hydroxyphenoxy) phenyl] sulfone; Can be mentioned.

The compound having a carboxyl group in the diamine compound represented by the general formula (5) includes
Benzenecarboxylic acids such as 3,5-diaminobenzoic acid and 2,4-diaminobenzoic acid, 3,3′-diamino,
4,4'-dicarboxybiphenyl, 4,4'-diamino, 3,3'-dicarboxybiphenyl, 4,4'-diamino, 2,2'-dicarboxybiphenyl, 4,4 '
Carboxybiphenyl compounds such as -diamino, 2,2 ', 5,5'-tetracarboxybiphenyl;
3'-diamino, 4,4'-dicarboxydiphenylmethane, 4,4'-diamino, 3,3'-dicarboxydiphenylmethane, 4,4'-diamino, 2,2'-dicarboxydiphenylmethane, 2,2- Bis [3-amino, 4-carboxyphenyl] propane, 2,2-bis [4-amino, 3-carboxyphenyl] propane,
2,2-bis [3-amino, 4-carboxyphenyl]
Hexafluoropropane, 4,4'-diamino, 2,2
Carboxydiphenylalkane compounds such as 2 ′, 5,5′-tetracarboxybiphenyl, 3,3′-diamino, 4,4′-dicarboxydiphenyl ether,
4,4'-diamino, 3,3'-dicarboxydiphenyl ether, 4,4'-diamino, 2,2'-dicarboxydiphenyl ether, 4,4'-azimino, 2,4
Carboxydiphenyl ether compounds such as 2 ′, 5,5′-tetracarboxydiphenyl ether;
3′-diamino, 4,4′-dicarboxydiphenylsulfone, 4,4′-diamino, 3,3′-dicarboxydiphenylsulfone, 4,4′-diamino, 2,2 ′,
Carboxydiphenylsulfone compounds such as 5,5′-tetracarboxydiphenylsulfone; bis (carboxyphenoxyphenyl) alkane compounds such as 2,2-bis [4- (4-amino, 3-carboxyphenoxy) phenyl] propane; Bis (carboxyphenoxy) biphenyl compounds such as 4,4'-bis (4-amino, 3-carboxyphenoxy) biphenyl, 2,2
Examples thereof include diamine compounds having a carboxyl group such as bis (carboxyphenoxyphenyl) sulfone compounds such as -bis [4- (4-amino, 3-carboxyphenoxy) phenyl] sulfone.

The other diamine compound (H ₂ N-
R ₆ -NH ₂ ) includes 1,4-diaminobenzene,
Diamines containing one benzene such as 1,3-diaminobenzene, 2,4-diaminotoluene, 1,4-diamino, 2,5-dihalogenobenzene, bis (4-aminophenyl) ether, bis (3- Aminophenyl) ether, bis (4-aminophenyl) sulfone, bis (3
-Aminophenyl) sulfone, bis (4-aminophenyl) methane, bis (3-aminophenyl) methane, bis (4-aminophenyl) sulfide, bis (3-aminophenyl) sulfide, 2,2-bis (4- Aminophenyl) propane, 2,2-bis (3-aminophenyl)
Propane, 2,2-bis (4-aminophenyl) hexafluoropropane, o-dianisidine, o-tolidine,
Diamines containing two benzenes such as tridine sulfonic acids, 1,4-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene,
1,4-bis (4-aminophenyl) benzene, 1,4
-Bis (3-aminophenyl) benzene, α, α′-bis (4-aminophenyl) -1,4-diisopropylbenzene, α, α′-bis (4-aminophenyl) -1,
Diamines containing three benzenes such as 3-diisopropylbenzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoro propane,
2,2-bis [4- (4-aminophenoxy) phenyl] sulfone, 4,4 ′-(4-aminophenoxy) biphenyl, 9,9-bis (4-aminophenyl) fluorene, 5,10-bis ( Diamine compounds such as diamines containing 4 or more benzenes such as 4-aminophenyl) anthracene. Hexamethylenediamine,
An aliphatic diamine compound such as diaminododecane can be used together with the diamine compound.

In the polyimide resin for underfill of the present invention, the polyimide siloxane component represented by the above general formula (1), the polyimide component represented by the above general formula (2) and the polyimide component represented by the above general formula (3) The percentage is
In order, 40 to 80 mol%, 5 to 50 mol% and the balance, preferably 50 to 80 mol% (particularly 50 to 70 mol%),
10 to 30 mol% and the balance (usually 0 to 40 mol%) (the sum of the components is 100 mol%). Further, the polyimide resin for underfill of the present invention preferably has an acid / amine (equivalent ratio) larger than 1, particularly preferably about 1.05 to 2 times. In this case, the terminal group of the polyimide resin for underfill of the present invention becomes an acid terminal (acid or acid anhydride terminal), and storage stability is improved when used in combination with an epoxy resin.

The polyimide resin for underfill of the present invention can be obtained, for example, by the following method. (1) An aromatic tetracarboxylic acid component and a diamine component comprising a diaminopolysiloxane represented by the above general formula (4), a diamine compound represented by the above general formula (5) and, if necessary, other diamine compounds. use,
A method of obtaining a polyimide resin by continuously polymerizing and imidizing at 15 to 250 ° C. in an organic polar solvent.

(2) Separating the diamine component, first, the excess amount of the aromatic tetracarboxylic acid component and the diaminopolysiloxane represented by the above general formula (4) are mixed in an organic polar solvent for 1 hour.
Polymerization and imidization at 5-250 ° C, average polymerization degree 1
An imide siloxane oligomer having an acid or acid anhydride group at about 10 terminals is prepared, and an aromatic tetracarboxylic acid component and an excess amount of the diamine compound represented by the above general formula (5) and, if necessary, other diamines The compound is polymerized and imidized in an organic polar solvent at 15 to 250 ° C. to prepare an imide oligomer having an amino group at the terminal having an average degree of polymerization of about 1 to 10, and then both are mixed to form 15 to 60 A method in which a block type polyimide resin is obtained by reacting at 130 ° C. and further raising the temperature to 130 to 250 ° C.

(3) A diamine comprising an aromatic tetracarboxylic acid component, a diaminopolysiloxane represented by the general formula (4), a diamine compound represented by the general formula (5), and if necessary, other diamine compounds. A method in which a component is first polymerized in an organic polar solvent at 20 to 80 ° C. to obtain a polyamic acid, and then imidized to obtain a polyimide resin.

As the organic polar solvent used for obtaining the above polyimide resin, a nitrogen-containing solvent such as N, N-
Dimethylacetamide, N, N-diethylacetamide, N, N-dimethylformamide, N, N-diethylformamide, N-methyl-2-pyrrolidone, 1,3-
Dimethyl-2-imidazolidinone, N-methylcaprolactam and the like; solvents containing a sulfur atom such as dimethylsulfoxide, diethylsulfoxide, dimethylsulfone, diethylsulfone and hexamethylsulfonamide; phenolic solvents such as cresol and phenol; Xylenol and the like; diglyme-based solvents such as diethylene glycol dimethyl ether (diglyme), triethylene glycol dimethyl ether (triglyme), and tetraglyme; solvents having an oxygen atom in the molecule such as acetone, methanol, ethanol, ethylene glycol, dioxane, and tetrahydrofuran; Other examples include pyridine and tetramethylurea. If necessary, an aromatic hydrocarbon solvent such as benzene, toluene and xylene, or another organic solvent such as solvent naphtha and benzonitrile may be used in combination.

As the polyimide resin for underfill of the present invention, those obtained by any of the above methods (1) to (3) may be used, but the imidization ratio is high and the high boiling point described later is high. It can be dissolved in a solvent at a high concentration of at least 40% by weight or more, preferably 45 to 65% by weight, particularly about 50 to 60% by weight, and has a solution viscosity at 25 ° C (E type rotational viscometer) of 10 to 10%. It is preferably 500 centipoise, particularly preferably 100 to 400 centipoise.

Next, the underfill material of the present invention will be described. The component (a) of the underfill material of the present invention comprises:
The underfill polyimide resin of the present invention described above.

The epoxy resin of the component (b) of the underfill material of the present invention (hereinafter sometimes abbreviated simply as epoxy) has an epoxy equivalent of 100 to 100.
A liquid or solid epoxy resin having a molecular weight of about 0 to about 300 to 5000 is preferable. For example, epoxy resin of bisphenol A type or bisphenol F type (manufactured by Yuka Shell: Epicoat 806, Epicoat 825)
Etc.) Trifunctional or higher functional epoxy resin (made by Yuka Shell: Epicoat 152, Epicoat 154, Epicoat 180)
Series, Epicoat 157 Series, Epicoat 10
32 series, manufactured by Ciba-Geigy: MT0163, etc.).

The amount of the epoxy resin used as the component (b) is 2 to 30 parts by weight, preferably 10 to 20 parts by weight, based on 100 parts by weight of the polyimide resin used as the component (a). If the amount is too large or too small, the adhesiveness is reduced, and the heat resistance and chemical resistance after curing are deteriorated. Therefore, the above range is preferable. Additives that promote the curing of the epoxy resin, such as hydrazides and imidazoles, may be used together with the epoxy resin.

Examples of the high boiling solvent of the component (c) of the underfill material of the present invention include the above-mentioned organic polar solvents which can be used for obtaining the underfill polyimide resin of the present invention of the component (a). But with a boiling point of 140
It is preferable to use one having a temperature of not lower than 210 ° C and not lower than 210 ° C. The use of an organic solvent having a boiling point of 180 ° C. or higher, particularly 200 ° C. or higher (eg, methyltriglyme) is optimal because the dissipation due to evaporation of the solvent is extremely reduced.

The amount of the high boiling point solvent used as the component (c) is as follows:
5 parts per 100 parts by weight of the polyimide resin of component (a)
0 to 140 parts by weight, preferably 55 to 120 parts by weight. If the amount is more than 140 parts by weight, cracks tend to occur in the dried film, and if it is less than 50 parts by weight, the viscosity increases and the filling rate into the voids decreases.

The underfill material of the present invention includes talc,
It is not preferable to add an inorganic filler such as mica or barium sulfate. However, Aerosil (submicron or less finely divided silica) may be added, and a pigment such as phthalocyanine green may be added. The aerosil preferably has an average particle diameter of 0.007 to 0.03 μm, and the amount of the aerosil is preferably 0.1 to 5 parts by weight based on 100 parts by weight of the polyimide resin of the component (a). The pigment has an average particle diameter of 0.01 to 0.1.
10 μm is preferable, and the amount of the component (a)
0.1 to 5 parts by weight based on 100 parts by weight of the polyimide resin. In addition, a small amount of carbon or the like can be added to the underfill material of the present invention for coloring, if necessary.

The underfill material of the present invention comprises the component (a)
A predetermined amount of the polyimide resin, the epoxy resin of the component (b), and other additional components such as aerosil and pigment, if necessary, is added to the high boiling point solvent of the component (c), and the mixture is easily stirred and mixed. Can be obtained. Further, the underfill material of the present invention can be obtained by adding the polymerization solution of the polyimide resin of the component (a) as it is or using a diluting solution obtained by diluting the polymerization solution with an appropriate organic solvent, and adding the component (a) to the polymerization solution or the diluting solution. b) adding a predetermined amount of epoxy resin and other additional components such as aerosil and pigment as needed,
It can also be easily obtained by uniformly stirring and mixing.

The underfill material of the present invention has a solution viscosity at 25 ° C. of 500 centipoise or less, preferably 100 to 100 centipoise.
400 centipoise is appropriate from the viewpoints of workability, physical properties of the solution, and properties of the cured film.

The underfill material of the present invention is, for example, as shown in FIGS. 1 and 2, a gap between a polyimide substrate 1 on which a copper circuit 2 is formed and a semiconductor chip 3 mounted on the substrate 1. By filling the gap between the adjacent bumps 4 and 4 and drying by heating to remove the solvent and to cure, the cured film 5 of the underfill material can be formed in the gap. In FIG. 1, about 80 copper circuits 2 as lead wires are shown, but usually about 400 or about 400 or more, and the pitch is 8
It is 0 μm or 80 μm or less. After the cured film 5 of the underfill material is formed, the surface of the copper circuit is protected by applying a coverlay (for example, "Pilalux" manufactured by DuPont, "Neofrex" manufactured by Mitsui Chemicals, Inc.).
Examples of a method of filling the gap with the underfill material include a method of dropping the underfill material into the gap, and the like.
The filling rate of the underfill material is preferably 0.5 cm / 1 minute or more, particularly preferably 1 cm / 1 minute or more. . The heating and drying may be performed, for example, at a temperature of about
Heat for about 120 minutes, then heat at a temperature of about 100 to 130 ° C for about 30 to 120 minutes, and finally 120 to 180
Multistage heating and drying, such as heating at a temperature of about 30 ° C. for about 30 to 120 minutes, is preferred.

[0036]

The present invention will be described in more detail with reference to examples and comparative examples below, but the present invention is not limited to these examples. The compounds used in the following Examples and Comparative Examples are shown below along with their abbreviations. a-BPDA: 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride DAPSi: α, ω-bis (3-aminopropyl) polydimethylsiloxane MBAA: bis (3-carboxy, 4-aminophenyl) Methane BAPP: 2,2-bis [4- (4-aminophenoxy) phenyl] propane

The physical properties were evaluated as follows. Viscosity: E type viscometer (Tokyo Keiki Co., Ltd.), 25 ° C, 1.34
° Measurement using a cone Cracks: The number of cracks observed by observing 200 places between bumps with a microscope. Filling speed: time required for filling between glass plates having a gap of 10 μm.

Example 1 a-BPDA (1.40 mol), MBAA (0.25 mol) and DAPSi (0.75 mol) were heated and stirred in a triglyme solvent at a temperature of 160 ° C. for 6 hours to obtain a polyimide solution. Was. This polyimide solution was a solution having a polymer solid content concentration of 56.5% by weight and a solution viscosity (25 ° C.) of 250 centipoise. Further, the imidation ratio was 100%. Epicoat 10 on 100 parts by weight of the above polyimide solution
32H60 (epoxy resin made by Yuka Shell) (15 parts by weight) and curing catalyst 2E4MZ (manufactured by Shikoku Chemicals) (0.3
Parts by weight) to obtain an underfill material. The solution viscosity (25 ° C.) of this underfill material was 350 centipoise, and the filling rate was 1 cm / min. The underfill material was dropped into a gap between a polyimide substrate on which a copper circuit was formed and a semiconductor chip mounted on the substrate. The underfill material could easily penetrate and fill the gap between the substrate and the chip without generating bubbles. This is 90 ° C. × 90 minutes + 100 ° C. × 30 minutes + 160
The film was heated and dried at three stages of ° C. × 60/60 to remove the solvent of the underfill material and cured to obtain a cured film. No crack was observed in this cured film (the number of cracks generated was 0). The number of cracks is the number of cracks observed between inner leads under microscopic observation.

COMPARATIVE EXAMPLE 1 MBAA (0.10 mol) and DAPS instead of MBAA (0.25 mol) and DAPSi (0.75 mol)
A cured film was obtained in the same manner as in Example 1 except that i (0.90 mol) was used. Solution viscosity of underfill material (25
° C) was 300 centipoise. In the obtained cured film, cracks were observed between the bumps (the number of occurrences of cracks was 1).
0).

Example 2 An underfill material was obtained in the same manner as in Example 1 except that Epicoat 1032H60 (25 parts by weight) was used instead of Epicoat 1032H60 (15 parts by weight). The solution viscosity of this underfill material was (25 ° C.) 400 centipoise. Using the underfill material, a cured film was obtained in the same manner as in Example 1. No cracks were observed in the obtained cured film (the number of cracks generated was 0).
Pieces).

Example 3 a-BPDA (1.40 mol), DAPSi (0.60 mol)
Mol), BAPP (0.30 mol) and MBAA (0.
(10 mol) in a triglyme solvent at a temperature of 160 ° C. for 6 hours with stirring to obtain a polyimide solution. This polyimide solution was a solution having a polymer solid content concentration of 53.4% by weight and a solution viscosity (25 ° C.) of 250 centipoise. Also,
The imidation ratio was 100%. The above polyimide solution 1
Epicoat 1032H60 (15 parts by weight)
And a curing catalyst 2E4MZ (0.3 parts by weight) were added to obtain an underfill material. The solution viscosity of this underfill material was (25 ° C.) 350 centipoise. The underfill material was dropped into a gap between a polyimide substrate on which a copper circuit was formed and a semiconductor chip mounted on the substrate. The underfill material could easily penetrate and fill the gap between the substrate and the chip without generating bubbles. This is 80 ° C x 30 minutes + 90 ° C x 45 minutes +
Heat drying was performed in four stages of 100 ° C. × 45 minutes + 160 ° C. × 60 minutes to remove and cure the solvent of the underfill material, thereby obtaining a cured film. No crack was observed in this cured film (the number of cracks generated was 0).

Example 4 The underfill material was dried by heating at 90 ° C. × 90 minutes + 160.
A cured film was obtained in the same manner as in Example 3 except that heating and drying were performed in two stages at 90 ° C. × 90 minutes. No crack was observed in the obtained cured film (the number of cracks generated was 0).

[0043]

The polyimide resin for underfill of the present invention is soluble in an organic solvent, and is particularly suitable for use in an underfill process when a circuit board on which a semiconductor chip is mounted is a polyimide substrate. is there. Also,
The underfill material of the present invention has good wettability with the polyimide film, can easily fill the narrow gap between the semiconductor chip and the polyimide substrate, has good adhesion with the polyimide substrate and the semiconductor chip, and causes cracks after curing. In addition, the cured film obtained has both excellent electrical properties and solder heat resistance, can prevent the migration of metal between bumps, and can reinforce semiconductor contacts.

[Brief description of the drawings]

FIG. 1 is a partially enlarged plan view showing an example of a state in which a cured film of an underfill material of the present invention is formed in a gap between a polyimide substrate and a semiconductor chip.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

[Explanation of symbols]

 Reference Signs List 1 polyimide substrate 2 copper circuit 3 semiconductor chip 4 bump 5 cured film of underfill material

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J002 CD05X CM04W EP016 EU016 EU026 EU116 EV206 GQ05 4J043 PA04 PC066 QB15 QB26 QB31 RA35 SA06 SA85 SB04 TA14 TA22 TB01 UA121 UA131 UB021 UB121 UB281 UB301 ZA02 ZA13 AB37A ABB AB47A BA09 BA18 CA15 CA21 CA26 CA46 CA51 CA54 CD12

Claims (3)

[Claims] 1. A polyimide siloxane component represented by the following general formula (1): 40 to 80 mol%, and a polyimide component represented by the following general formula (2): 5 to 50 mol%.
A polyimide resin for underfill comprising mol% and the remainder of the polyimide component represented by the following formula (3) (total of 100 mol% of each component). Embedded image Embedded image Embedded image 2. An underfill material comprising the following components (a), (b) and (c) and having a solution viscosity at 25 ° C. of 500 centipoise or less. (A) 100 parts by weight of the polyimide resin for underfill according to claim 1 (b) 2 to 30 parts by weight of an epoxy resin (c) 50 to 140 parts by weight of a high boiling point solvent 3. The method according to claim 2, wherein the space between the polyimide substrate and the semiconductor chip mounted on the substrate is filled with the underfill material according to claim 2, and then heated and dried to be cured. Cured film of underfill material.