JPH0940931A - Heat-resistant adhesive and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a thin semiconductor device with a high reliability without using an adhesive tape by using a heat-resistant polyimide adhesive obtd. from 2,2-bis(3, 4-dicarboxyphenyl) hexafluoroisopropylidene dianhydride and a specific diamine mixture. SOLUTION: 2, 2-Bis(3,4-dicarboxyphenyl) hexafluoroisopropylidene dianhydride (A) represented by formula I is reacted with an equimolar amt. of a diamine mixture comprising a diamine (B) represented by formula II[wherein R<1> to R<4> are each H or a 1-4C alkyl or alkoxy provided at least two of them are each a 1-4C alkyl or alkoxy; and X is CH2 , C(CH2 )2 , O, CO, etc.] and a siloxanediamine (C) represented by formula III(wherein R<5> to R<8> are each an org. group; and (m) is 1-100) to give a heat-resistant polyimide adhesive contg. 5-90mol% condensed AB units and 0.5-30mol% condensed AC units. Pref. 100 pts.wt. thus obtd. adhesive is compounded with up to 15 pts.wt. coupling agent. This adhesive is suitable for bonding a semiconductor chip of a semiconductor device of an LOC structure to a lead frame without using a substrate tape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat resistant adhesive and a semiconductor device, and more particularly to a specific polyimide heat resistant adhesive and a semiconductor device using this adhesive.

[0002]

2. Description of the Related Art In recent years, due to the increase in semiconductor chip area accompanying the high integration of semiconductors, the structure of a conventional semiconductor device (also called a semiconductor package) cannot accommodate a semiconductor chip. In order to solve this, a semiconductor device having a lead-on-chip (LOC) structure capable of increasing the storage rate of semiconductor chips has been developed. A semiconductor device having a LOC structure has a structure in which a lead frame is arranged above a semiconductor chip via an adhesive as shown in FIG. 1, and the semiconductor chip (2) is bonded to the lead frame (3) with the adhesive (1). Then, the electrodes of the semiconductor chip and the lead frame are connected (wire bonded) with a wire (4), and the semiconductor chip, the bonding portion between the semiconductor chip and the lead frame, and the wire connection portion are sealed with a sealing material (5). Manufactured. Conventionally, a double-sided adhesive-attached tape has been mainly used as the adhesive.

[0003]

However, the double-sided adhesive-coated tape used here has a structure in which the adhesive is applied to both sides of an insulating film having a thickness of about 50 μm (the total thickness is about 100 μm), the total thickness is 100 μm
It is difficult to set the thickness to m or less, and there is a drawback that the thickness of the semiconductor device cannot be reduced by the thickness occupied by the base tape.
Further, when the adhesive or the sealing material absorbs moisture, the moisture expands due to heat at the time of solder connection, and as a result, there is a problem that cracks occur in the semiconductor device. An object of the present invention is to provide a semiconductor device thinner than before and a heat-resistant adhesive suitable for the semiconductor device by using only an adhesive without using a tape with double-sided adhesive (in other words, a base tape). It is to be.

[0004]

The present invention relates to the following heat resistant adhesive (1) or (2) and a semiconductor device (3). (1) 5-90 mol% of the structural unit represented by the general formula (I) and 0.5-30% of the structural unit represented by the general formula (II).
Heat resistant adhesive containing mol%.

Embedded image

Embedded image [In the formulas (I) and (II), R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, a C1-4 alkyl group or C1.
A ~ 4 alkoxy groups, and at least two of these indicates an alkyl group or C1 -4 alkoxy group C1 -4, X is, -CH ₂ -, - C
_{(CH 3) 2 -, -} O -, - SO 2 -, - CO- or -N
HCO-, R ⁵ and R ⁸ each represent a divalent organic group, R ⁶ and R ⁷ each represent a monovalent organic group,
m represents an integer of 1 to 100. (2) A heat-resistant adhesive which further contains a coupling agent in an amount not exceeding 15 parts by weight based on 100 parts by weight of the adhesive of (1) above.

(3) A semiconductor device using the heat-resistant adhesive, that is, a lead frame and a semiconductor chip are bonded by an adhesive formed on the surface of the semiconductor chip, and the electrodes on the semiconductor chip and the lead frame are bonded to each other. Of the general formula (II), wherein (i) the adhesive is composed of 5 to 90 mol% of the structural unit represented by the general formula (I). A semiconductor device which is a heat-resistant adhesive containing 0.5 to 30 mol% of a structural unit represented by the formula; or (ii)
The adhesive is composed of structural units 5 to 9 represented by the general formula (I).
0 mol% and the structural unit represented by the general formula (II) 0.5 to 3
A semiconductor device which is a heat-resistant adhesive containing 100 parts by weight of a heat-resistant adhesive containing 0 mol% and further containing a coupling agent in an amount not exceeding 15 parts by weight.

The heat-resistant adhesive of the present invention containing 5 to 90 mol% of the structural unit represented by the general formula (I) and 0.5 to 30 mol% of the structural unit represented by the general formula (II) is , Formula (II
I)

Embedded image 2,2-bisphthalic acid hexafluoroisopropylidene dianhydride (abbreviated as 6FDA) or an amide-forming derivative of a free acid, acid halide, acid ester or the like (containing 50 mol% or more of all acid components) ) Containing "acid component"
And the general formula (IV)

[Chemical 6] [In the formula (IV), R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, a C1-4 alkyl group or a C1-4 alkoxy group, and at least these the two indicates an alkyl group or C1 -4 alkoxy group C1 -4, X _{is, -CH 2 -, - C (} CH 3) 2 -,
_{-O -, - SO 2 -,} - shows a CO- or -NHCO-. ] The diamine represented by these, or the corresponding diisocyanate (10-90 mol% content of all diamine components), and general formula (V).

[Chemical 7] [In the formula (V), R ⁵ and R ⁸ each represent a divalent organic group, R ⁶ and R ⁷ each represent a monovalent organic group, and m
Represents an integer of 1 to 100. ] The "diamine component" containing the siloxane diamine represented by or the corresponding diisocyanate (containing 1 to 30 mol% of the total diamine component) has an acid component / diamine component amount ratio of equimolar or almost equimolar. Thus, it is obtained by reacting this.

It is preferable that the heat-resistant adhesive obtained further contains a coupling agent. The purpose of adding the coupling agent is to further improve the adhesive force or reflow crack resistance of the adhesive, and the heat-resistant adhesive 1
An amount not exceeding 15 parts by weight with respect to 00 parts by weight is added.

The heat-resistant adhesive of the present invention is preferably used for a semiconductor device, particularly a semiconductor device having a LOC structure as shown in FIG. In this case, the heat resistant adhesive of the present invention is formed on the circuit element (active element) surface of the semiconductor chip.

The semiconductor chip used is silicon (S
i) On a substrate such as a wafer or a gallium arsenide (GaAs) wafer, a circuit element (active element) that is an element constituting an electronic circuit such as a transistor, a diode, a resistor, or a capacitor is manufactured, and further Si ₃ N ₄ is manufactured. , SiO ₂ , PS
An inorganic insulating film such as G (phosphosilicate glass) and a wiring of a metal such as aluminum are formed, a part of the wiring is used as an electrode for an external connection terminal, and a surface is formed on a portion other than an electrode portion serving as an external connection terminal. On a semiconductor chip (shown in FIG. 2A of FIG. 2) on which a protective organic protective film is formed, or on a substrate such as a silicon wafer, a circuit element, which is an element that constitutes an electronic circuit such as a transistor, is manufactured.
An example is a semiconductor chip (shown in FIG. 3A) in which an inorganic insulating film such as i ₃ N ₄ and a metal wiring such as aluminum are formed, and a part of the wiring is used as an electrode for an external connection terminal.

A method of forming an adhesive having a desired pattern on the active element surface of the semiconductor chip can be performed by the method described below. The thickness of the adhesive varies depending on the structure and electrical characteristics of the semiconductor device, and also depends on whether the adhesive also serves as the surface protective film. ˜50 μm. After the adhesive is formed on the surface of the semiconductor chip, the semiconductor chip is pressed against the lead frame while heating at a temperature above the melting temperature of the adhesive to bond the lead frame and the semiconductor chip, and then the electrodes and leads of the semiconductor chip. A semiconductor device is manufactured by connecting (wire bonding) a wire to a frame with a wire such as a gold wire, and then sealing the semiconductor chip, the bonding portion between the semiconductor chip and the lead frame, and the wire connecting portion with a sealing material. .

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The amount of 2,2-bisphthalic acid hexafluoroisopropylidene dianhydride (or its amide-forming derivative) of the formula (III) used in the production of the heat-resistant adhesive of the present invention is 50 mol% or more, preferably 70 mol% or more of the total acid components. Other acid anhydrides may be used in combination for improving the properties of the adhesive. When the amount of 2,2-bisphthalic acid hexafluoroisopropylidene dianhydride used is less than 50 mol% of all the acid components (that is, when the amount of other acid anhydride used exceeds 50 mol%), the dielectric constant is It becomes high and is not preferable.

Other acid anhydrides which may be used in combination include trimellitic anhydride, pyromellitic dianhydride, 3,
3 ', 4,4'-benzophenone tetracarboxylic dianhydride (BTDA), 3,3', 4,4'-biphenyltetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride , Bis (3,4-dicarboxyphenyl) sulfone dianhydride (DSDA), 4,
4'-bis (3,4-dicarboxyphenoxy) diphenyl sulfone dianhydride, 2,2-bis [4- (3,4-
Dicarboxyphenoxy) phenyl] propane dianhydride, ethylene glycol bis trimellitate dianhydride (EBTA), decamethylene glycol bis trimellitate dianhydride (DBTA), bisphenol A bis trimellitate dianhydride (BABT), 2, 2-bis [4-
(3,4-Dicarboxyphenylbenzoyloxy) phenyl] hexafluoropropane dianhydride, 4,4′-
[1,4-phenylenebis (1-methylethylidene)]
Examples thereof include bisphenyl bis trimellitate dianhydride.

In the production of the heat-resistant adhesive of the present invention, the amount of the diamine of the general formula (IV) used (when diisocyanate is used instead of diamine, the amount of the corresponding diisocyanate used; the same applies hereinafter) is The total amount of diamines is 10 to 90 mol%, preferably 30 to 80 mol%. If the diamine of the general formula (IV) is less than 10 mol% of all diamines, the water absorption rate and the dielectric constant are large, and the diamine is 90 mol%.
If it exceeds, the adhesive strength decreases.

Examples of the diamine of the general formula (IV) include 4,4'-diamino-3,3 ', 5,5'-tetramethyldiphenylmethane, 4,4'-diamino-3,3', 5.
5'-tetraethyldiphenylmethane, 4,4'-diamino
-3,3 ', 5,5'-Tetra-n-propyldiphenylmethane, 4,4'-diamino-3,3', 5,5'-tetraisopropyldiphenylmethane, 4,4'-diamino-3,3 ' ，
5,5'-tetrabutyldiphenylmethane,

4,4'-diamino-3,3'-dimethyl-5,
5'-diethyldiphenylmethane, 4,4'-diamino-
3,3'-dimethyl-5,5'-diisopropyldiphenylmethane, 4,4'-diamino-3,3'-diethyl-5,5'-
Diisopropyldiphenylmethane, 4,4'-diamino-
3,5-Dimethyl-3 ', 5'-diethyldiphenylmethane, 4,4'-diamino-3,5-dimethyl-3', 5'-diisopropyldiphenylmethane, 4,4'-diamino-3
5-diethyl-3 ', 5'-diisopropyldiphenylmethane, 4,4'-diamino-3,5-diethyl-3', 5'-dibutyldiphenylmethane,

4,4'-diamino-3,5-diisopropyl
-3 ', 5'-dibutyldiphenylmethane, 4,4'-diamino-3,3'-diisopropyl-5,5'-dibutyldiphenylmethane, 4,4'-diamino-3,3'-dimethyl-5,
5'-dibutyldiphenylmethane, 4,4'-diamino-
3,3'-diethyl-5,5'-dibutyldiphenylmethane,

4,4'-diamino-3,3'-dimethyl-
Diphenylmethane, 4,4'-diamino-3,3'-diethyl-diphenylmethane, 4,4'-diamino-3,3 '
-Di-n-propyldiphenylmethane, 4,4'-diamino-3,3'-diisopropyldiphenylmethane, 4,
4'-diamino-3,3'-dibutyldiphenylmethane,

4,4'-diamino-3,3 ', 5-trimethyldiphenylmethane, 4,4'-diamino-3,3',
5-triethyldiphenylmethane, 4,4'-diamino-3,3 ', 5-tri-n-propyldiphenylmethane, 4,4'-diamino-3,3', 5-triisopropyldiphenylmethane, 4,4'-diamino -3, 3 ', 5
-Tributyldiphenylmethane,

4,4'-diamino-3-methyl-3'-ethyldiphenylmethane, 4,4'-diamino-3-methyl-3'-isopropyldiphenylmethane, 4,4'-diamino-3-ethyl-3 ' -Isopropyldiphenylmethane, 4,4'-diamino-3-ethyl-3'-butyldiphenylmethane, 4,4'-diamino-3-isopropyl-3'-butyldiphenylmethane,

4,4'-diamino-2,2'-bis (3,4
3 ', 5,5'-tetramethyldiphenyl) isopropane, 4,4'-diamino-2,2'-bis (3,3',
5,5'-tetraethyldiphenyl) isopropane,
4,4'-diamino-2,2'-bis (3,3 ', 5,5'
-Tetra-n-propyldiphenyl) isopropane, 4,
4'-diamino-2,2'-bis (3,3 ', 5,5'-tetraisopropyldiphenyl) isopropane, 4,4'
-Diamino-2,2'-bis (3,3 ', 5,5'-tetrabutyldiphenyl) isopropane,

4,4'-diamino-3,3 ', 5,5'-
Tetramethyldiphenyl ether, 4,4'-diamino-3,3 ', 5,5'-tetraethyldiphenyl ether, 4,4'-diamino-3,3', 5,5'-tetra-
n-propyl diphenyl ether, 4,4'-diamino-3,3 ', 5,5'-tetraisopropyl diphenyl ether, 4,4'-diamino-3,3', 5,5'-tetrabutyl diphenyl ether,

4,4'-diamino-3,3 ', 5,5'-
Tetramethyldiphenyl sulfone, 4,4'-diamino-3,3 ', 5,5'-tetraethyldiphenyl sulfone, 4,4'-diamino-3,3', 5,5'-tetra n
-Propyldiphenyl sulfone, 4,4'-diamino-
3,3 ′, 5,5′-tetraisopropyldiphenylsulfone, 4,4′-diamino-3,3 ′, 5,5′-tetrabutyldiphenylsulfone,

4,4'-diamino-3,3 ', 5,5'-
Tetramethyl diphenyl ketone, 4,4'-diamino-
3,3 ′, 5,5′-tetraethyldiphenylketone,
4,4'-diamino-3,3 ', 5,5'-tetra n-propyl diphenyl ketone, 4,4'-diamino-3,
3 ', 5,5'-tetraisopropyl diphenyl ketone,
4,4'-diamino-3,3 ', 5,5'-tetrabutyldiphenylketone,

4,4'-diamino-3,3 ', 5,5'-
Tetramethylbenzanilide, 4,4'-diamino-
3,3 ', 5,5'-tetraethylbenzanilide, 4,
4'-diamino-3,3 ', 5,5'-tetra-n-propylbenzanilide, 4,4'-diamino-3,3', 5
5'-tetraisopropylbenzanilide, 4,4'-diamino-3,3 ', 5,5'-tetrabutylbenzanilide and the like can be mentioned.

In the production of the heat-resistant adhesive of the present invention, the amount of the siloxane diamine of the general formula (V) used is 1 to 30 mol% of the total diamine, preferably 3 to 25.
Mol%. If the diamine of the general formula (V) is less than 1 mol% of all the diamines, the adhesive force is low, and if it exceeds 30 mol%, the Tg and the adhesive force are lowered.

R ⁵ and R ⁸ in the general formula (V) are each independently a trimethylene group, a tetramethylene group, a phenylene group, a toluylene group or the like, and R ⁶ and R ⁷ are each independently a methyl group. , an ethyl group, there are phenyl group, a plurality of R ⁶ and a plurality of R ⁷ may be the same as or different from each other. The siloxane diamine of the general formula (V), wherein R ⁵ and R ⁸ are both trimethylene groups, and R ⁶ and R ⁷ are both methyl groups, can be obtained from Shin-Etsu Chemical Co., Ltd. "LP-7100"
(M is 1), "X-22-161AS" (m is about 10 on average), "X-22-161A" (m is about 20 on average), "X-22-161B""(M
Is about 30), "X-22-161C"
(M having an average of around 50) and "X-22-161
They are sold under the trade name of "E" (m having an average of around 100).

In addition to the diamine of the general formula (IV) and the siloxane diamine of the general formula (V), "other diamine" is used in combination in the range of 0 to 49 mol% with respect to the total diamine in order to improve the properties of the adhesive. You may. If the amount of the "other diamine" used exceeds 49 mol% with respect to all the diamines, the water absorption rate and the dielectric constant increase, which is not preferable. . "Other diamines" that can be used in combination include paraphenylenediamine, metaphenylenediamine, metatoluylenediamine,

4,4'-diaminodiphenyl ether (DDE), 4,4'-diaminodiphenylmethane,
4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone,

1,4-bis (4-aminocumyl) benzene (BAP), 1,3-bis (4-aminocumyl) benzene, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (3) -Aminophenoxy) benzene,
1,4-bis (4-aminophenoxy) benzene, 2,
2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP), 2,2-bis [4- (3-aminophenoxy) phenyl] propane,

Bis [4- (3-aminophenoxy) phenyl] sulfone (m-APPS), bis [4- (4-aminophenoxy) phenyl] sulfone, 2,2-bis [4- (4-aminophenoxy)) Phenyl] hexafluoropropane, and the like.

When diisocyanate is used in place of the diamines of the formulas (IV) and (V) or the above "other diamines", examples of the diisocyanate are those in which the amino group of the diamine shown above is replaced with an isocyanate group. Can be mentioned.

The heat-resistant adhesive of the present invention comprises a "acid component" containing 2,2-bisphthalic acid hexafluoroisopropylidene dianhydride of the formula (III) or an amide-forming derivative thereof, and a general formula (IV) Of the diamine (or the corresponding diisocyanate) and the "diamine component" containing the siloxane diamine of the general formula (V) (or the corresponding diisocyanate) have an acid component / diamine component amount ratio of equimolar or almost equimolar. Thus, it is manufactured by reacting under appropriate conditions. At this time, the degree of imidation of the generated polyimide can be appropriately adjusted by selecting the conditions. The reaction conditions are, for example, 100 ° C. or higher, particularly 120 ° C. or higher,
When reacted in the presence of a catalyst such as tributylamine, triethylamine, triphenyl phosphite or the like, a completely or almost completely imidized polyimide can be produced.

By reacting at 80 ° C. or lower, particularly 50 ° C. or lower, a polyamic acid which is a precursor of polyimide and is hardly or hardly imidized can be produced. It is also possible to produce a polyimide precursor in which imidization is partially advanced.

The polyamic acid or the polyimide precursor partially imidized is further treated at 100 ° C. or higher,
In particular, a method of heating at 120 ° C. or higher for imidization, an acid anhydride such as acetic anhydride, propionic anhydride, or benzoic anhydride, a ring-closing agent such as carbodiimide such as dicyclohexylcarbodiimide, and further pyridine, isoquinoline, trimethylamine as necessary. , Ring-closing catalysts such as aminopyridine and imidazole are chemically closed (imidized) (the ring-closing agent and the ring-closing catalyst are used in the range of 1 to 8 mol per 1 mol of the acid anhydride, respectively). The (preferred) method makes it possible to produce polyimides whose imidization is almost or completely completed. These reactions are usually performed in an organic solvent. The heat resistant adhesive of the present invention is preferably a completely or almost completely imidized polyimide.

The organic solvent that can be used in the reaction includes N,
N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethylsulfoxide, hexamethylphosphoramide, phenol, m-
There are cresol, chlorobenzene, etc., and two or more kinds may be mixed and used as long as they are compatible with each other. These organic solvents can also be used as a solvent for diluting or dissolving the heat-resistant adhesive of the present invention.

A coupling agent is preferably added to the above heat-resistant adhesive. The amount of the coupling agent added is not more than 15 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the heat-resistant adhesive.
If the coupling agent is added in excess of 15 parts by weight, the adhesive becomes too hard and the adhesive strength is reduced, which is not preferable.

The coupling agent used is a silane coupling agent, that is, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyl. Epoxysilane such as trimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinylsilane such as γ-methacryloxytrimethoxysilane, γ-aminopropyltriethoxysilane, γ
-Aminopropyltrimethoxysilane, N-phenyl-
In addition to aminosilanes such as γ-aminopropyltrimethoxysilane and mercaptosilanes such as γ-mercaptopropyltrimethoxysilane, and the like, coupling agents such as titanate, aluminum chelate, and zirconate can be used, but preferably silane coupling. Agents, more preferably epoxysilane coupling agents.

The heat-resistant adhesive of the present invention may be further added with an organic component such as polymaleimide, epoxy resin or organic silicone particles, or an inorganic filler such as silica particles or alumina particles.

The heat-resistant adhesive of the present invention is also characterized by a low dielectric constant in addition to heat resistance. The low dielectric constant is advantageous for speeding up signal transmission and also has an advantage that the adhesive layer can be thin.

FIG. 1 shows a schematic sectional view of an example of a semiconductor device according to the present invention. In FIG. 1, 1 is an adhesive, 2 is a semiconductor chip, 3 is a lead frame, 4 is a wire, and 5 is a sealing material. The heat resistant adhesive of the present invention is particularly preferably used for a semiconductor device having a LOC structure as shown in FIG.

The following properties are preferably required as the properties of the heat resistant adhesive of the present invention used for a semiconductor device. That is, the glass transition temperature (Tg) is preferably 150 to 350 ° C, more preferably 170 to 300 ° C,
More preferably 200 to 290 ° C., the water absorption rate is preferably 3% by weight or less, the “protrusion length” (an index representing the fluidity of the resin) is preferably 2 mm or less, and further preferably 1 m.
m or less, more preferably 0.5 mm or less. When the glass transition temperature is lower than 200 ° C. or when the “protrusion length” is 1 mm to 2 mm, the water absorption is preferably less than 1.5% by weight. "Overhang length"
Is measured by the following method. "Overhang length" measurement: 19mm x 50mm (length x
Horizontal), 25 μm thick film adhesive at 350 ° C., 3
When pressed under the conditions of MPa and 1 minute, the length of the adhesive that protrudes from the long side (for one side) is measured at the center of the piece, and the value (mm) is taken as the protruding length.

Typical examples of application of the heat-resistant adhesive of the present invention to a semiconductor device are shown schematically in FIGS. 2 and 3. FIG. 2 shows that a heat-resistant adhesive (1) is formed on a part of the active element surface of a semiconductor chip (2A) with an organic protective film,
The semiconductor chip and the lead frame (3) are adhered to each other, and the electrodes (8) of the semiconductor chip and the lead frame (3) are attached.
It is a cross-sectional schematic diagram of (2B) when and are connected by the wire (4). In FIG. 3, a heat-resistant adhesive (1) is formed (3B) on the entire surface of the semiconductor chip shown in FIG. 3A except for the electrode (8) on the active element surface, and the heat-resistant adhesive (1) is applied. The semiconductor chip and the lead frame (3) are bonded by using the electrode (8) and the lead frame (3) with the wire (4).
It is a cross-sectional schematic diagram at the time of connecting by (3C). 2 and 3, 1 is an adhesive, 2 is a semiconductor chip, 3 is a lead frame, 4 is a wire, 6 is a silicon wafer, 7 is a circuit element, 8 is aluminum wiring (electrode portion), and 8'is aluminum wiring. , 9 are inorganic insulating films, and 10 are organic protective films.

When a semiconductor chip having a structure as shown in FIG. 2A is used, the heat-resistant adhesive has a pattern in which at least the electrode portion is exposed and which has an area necessary for the adhesion, and the active element is used. It is formed on a part of the surface.
In this case, the heat resistant adhesive of the present invention serves as an adhesive (2B in FIG. 2).

When the semiconductor chip having the structure shown in FIG. 3A is used, the heat-resistant adhesive replaces the organic protective film (10) in 2A of FIG. Is a pattern covering the entire surface and is formed on the active element surface (3B in FIG. 3). In this case, the heat-resistant adhesive of the present invention serves as both the surface protective film and the adhesive of the portion other than the electrode portion on the active element surface (3 in FIG. 3).
C).

The adhesive can be formed on the active element surface of the semiconductor chip in a desired pattern, for example, a pattern in which the electrode portion is exposed and the other surface is covered, as follows. (A) An adhesive (organic solvent-soluble resin) film layer is formed on the semiconductor chip by a method such as spin coating or doctor blade; (B) A resist image having a desired pattern is formed on it (C) Organic It is treated with a solvent to etch and remove the organic solvent-soluble resin film layer in the portion not covered with the resist image; (D) The resist image peeling liquid is treated to peel the resist image from the organic solvent-soluble resin film layer And (E) treat with alcohol.

There are various methods for forming a resist image of a desired pattern (which is a layer made of a material that is not eroded by an etching solution and has resistance) on a semiconductor chip, but it is usually soluble in an organic solvent. A layer of a resist image forming material (also simply referred to as “resist”) is formed on the resin film layer, exposed through a photomask having a desired pattern, treated with a developing solution, and formed. The resist image stripping solution contains 0.01 to 10.0 parts by weight of arylsulfonic acid such as benzenesulfonic acid, toluenesulfonic acid, and toluenesulfonic acid with respect to 100 parts by weight of the solvent, and the solubility of the solvent. Parameter is 5.0-1
A stripper that is 1.0 (eg, xylene, cyclohexane, toluene, etc.) can be used.

As another method of forming the adhesive having a desired pattern on the active element surface of the semiconductor chip, a screen printing method may be used. The electrodes on the semiconductor chip can be exposed by these methods.

As described above, the heat-resistant adhesive of the present invention is preferably used in a semiconductor device having a LOC structure. However, the heat-resistant adhesive of the present invention is formed on the back surface of a semiconductor chip or a lead frame. Accordingly, the present invention can be applied to a semiconductor device having another structure, for example, a semiconductor device having a structure in which a semiconductor chip is located above a lead frame.

[0049]

The present invention will be described in detail below with reference to examples. Example 1 A four-necked flask equipped with a stirrer, a thermometer, a nitrogen gas inlet tube and a calcium chloride tube was charged with 4, 4 as a diamine component.
2.75 g of 4'-diamino-3,3 ', 5,5'-tetraisopropyldiphenylmethane (IPDDM) (7.
5 mmol), 0.62 g (2.5 mmol) of "LP-7100" (siloxane diamine), and 23.4 g of N, N-dimethylformamide (DMF) as a solvent were added and dissolved. Next, 2,2-bisphthalic acid hexafluoroisopropylidene dianhydride (6FDA) as an acid anhydride component was cooled while cooling the reaction solution so as not to exceed 5 ° C.
After adding 4.4 g (10 mmol) little by little, the mixture was cooled to 5 ° C for 1 hour while cooling, and then at room temperature for 6 hours.
The reaction was carried out for a time to obtain a polyamic acid varnish. To the obtained polyamic acid varnish, 2.55 g of acetic anhydride and 1.98 g of pyridine were added and reacted at room temperature for 3 hours to obtain a polyimide. The obtained polyimide varnish was poured into water and the resulting precipitate was separated, pulverized and dried to obtain a polyimide powder.

This polyimide powder was dissolved in DMF, and the resulting varnish was cast on a glass plate. 10 at 100 ° C
After minute drying, it was peeled off, fixed on an iron frame and dried at 250 ° C. for 1 hour to obtain a film. The thickness of the film thus obtained was 25 μm, and the glass transition temperature (Tg) was 215 ° C. when measured with a thermomechanical tester (TMA).
The water absorption rate when immersed in water at 0 ° C. for 24 hours was 0.3% by weight, and the dielectric constant at 1 MHz was 2.6. Separately, γ-glycidoxypropyltrimethoxysilane (SH6040: 100 parts by weight of the polyimide powder).
(Toray Silicone Co., Ltd.) 3 parts by weight was dissolved in DMF, the resulting varnish was cast on a glass plate, and the "protrusion length" of the film obtained in the same manner as above was measured to be 0.5 mm. Met.

100 g of the above polyimide powder and γ-glycidoxypropyltrimethoxysilane (SH6040) 3
The varnish obtained by dissolving 400 g of N-methyl-2-pyrrolidone in 400 g was applied on a silicon wafer by spin coating to a thickness of 30 μm, heated at 120 ° C. for 30 minutes, and then heated at 275 ° C. for 10 minutes to bond. A wafer coated with the agent was obtained.
After the adhesive on the electrode portion was removed from the adhesive-coated wafer using a photosensitive resist, the wafer was diced and cut into chips. After this chip was attached to a lead frame under the conditions of 375 ° C. and 3 MPa, wire bonding was performed,
A semiconductor device was assembled by sealing with a sealing material. When this semiconductor device was made to absorb moisture under the conditions of 85 ° C. and 85% RH for 48 hours and then solder reflow was performed in an infrared furnace at 245 ° C., no crack was generated in this semiconductor device.

Example 2 As a diamine component, 4,4'-diamino-3,3 ',
5,5'-tetraisopropyldiphenylmethane (IP
DDM) 2.75 g (7.5 mmol), "161A
S "(siloxane diamine) 0.62 g (1.5 mmol) and 2,2-bis [4- (4-aminophenoxy)
Phenyl] propane (BAPP) 0.41 g (1.0 mmol) was used, and 2,2-bisphthalic acid hexafluoroisopropylidene dianhydride (6FD
A) 4.4 g (10 mmol) was used and otherwise the same operation as in Example 1 was carried out to obtain a polyimide, and then the film was obtained. When the physical properties of the film were measured in the same manner as in Example 1, Tg was 230 ° C. and the water absorption rate was 0.3% by weight, 1 MH
The dielectric constant of z was 2.7. Further, 3 parts by weight of γ-glycidoxypropyltrimethoxysilane (SH6040) was dissolved in DMF with respect to 100 parts by weight of the above polyimide powder, and the obtained varnish was cast on a glass plate.
The "protruding length" of the film obtained in the same manner as above was 0.3 mm. When a semiconductor device was manufactured in the same manner as in Example 1 and solder reflow was performed, no crack was generated.

Comparative Example 1 As the diamine component, 4,4'-diamino-3,
3.66 g (10.0 mmol) of 3 ′, 5,5′-tetraisopropyldiphenylmethane (IPDDM) was used, and 2,2-bisphthalic acid hexafluoroisopropylidene dianhydride (6FDA) was used as an acid anhydride component. 4 g
The same procedure as in Example 1 was carried out except that (10 mmol) was used to obtain a polyimide, and then the film was obtained. When the physical properties of the film were measured in the same manner as in Example 1, the Tg was 400 ° C. or higher, the water absorption was 0.3% by weight, and the dielectric constant at 1 MHz was 2.6. When a semiconductor device was manufactured in the same manner as in Example 1 and solder reflow was performed, cracks occurred due to peeling between the adhesive layer and the semiconductor chip and between the adhesive layer and the sealing material.

[0054]

The heat-resistant adhesive according to claim 1 is suitable as an adhesive for semiconductor devices, does not require a base tape, and can provide a semiconductor device thinner than before. The semiconductor device according to claim 3 has excellent package crack resistance during solder reflow and high reliability.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an example of a semiconductor device having a LOC structure.

FIG. 2 shows a case where a semiconductor chip with an organic protective film (2A) is used, a heat-resistant adhesive is formed on a part of the active element surface, and the semiconductor chip and the lead frame are bonded to each other (2
It is a cross-sectional schematic diagram which shows B).

FIG. 3 is a diagram illustrating a semiconductor chip (3A) before applying an organic protective film, a heat-resistant adhesive is formed on the entire surface other than electrodes on the active element surface (3B), and the semiconductor chip and leads are formed by the heat-resistant adhesive. It is a cross-sectional schematic diagram which shows the place (3C) bonded to the frame.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Heat-resistant adhesive 2 ... Semiconductor chip 3 ... Lead frame 4 ... Wire 5 ... Sealing material 6 ... Silicon wafer 7 ... Circuit element 8 ... Aluminum wiring (electrode part) 8 '... Aluminum wiring 9 ... Inorganic insulating film 10 ... Organic protective film

Claims (3)

[Claims] 1. A structural unit represented by the general formula (I): 5 to 90
Mol% and the structural unit represented by the general formula (II) 0.5 to 3
A heat-resistant adhesive containing 0 mol%. Embedded image Embedded image [In the formulas (I) and (II), R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, C
1 to 4 alkyl groups or C1 to 4 alkoxy groups, and at least two of them are C1 to 4 alkyl groups or C1 to 4 alkoxy groups, and X is- _{CH 2 -, - C (CH} 3) 2 -, - O -, - SO 2
-, -CO- or -NHCO- is shown, R ⁵ and R ⁸ are each a divalent organic group, R ⁶ and R ⁷ are each a monovalent organic group, and m is 1 to 100. Indicates an integer. ] 2. With respect to 100 parts by weight of the adhesive of claim 1,
Further, a heat resistant adhesive containing a coupling agent in an amount not exceeding 15 parts by weight. 3. A lead frame and a semiconductor chip are adhered to each other with an adhesive formed on the surface of the semiconductor chip to electrically connect an electrode of the semiconductor chip and the lead frame,
A semiconductor device sealed with a sealing material, wherein the adhesive is the heat-resistant adhesive according to claim 1.