JP2003160773A - Composite adhesive sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite adhesive sheet capable of adhering to an object to be adhered such as a lead-frame, a metal plate, a ceramic plate and an organic wiring board. <P>SOLUTION: This composite adhesive sheet is obtained by applying a varnish of a heat resistant resin containing a composing unit expressed by formula (3) on one or both surfaces of a surface-treated heat resistant film, and heating to form an adhesive layer(s). The resin in the adhesive layer has a glass transition temperature of ≥250°C and includes aromatic groups expressed by formulae (4) to (8), and 10 to 90 mol% of linkage groups linking to these aromatic groups are amide groups. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a lead frame,
The present invention relates to a composite sheet that can be adhered to an adherend such as a metal plate, a ceramic plate and an organic wiring board. In particular, the present invention relates to a composite sheet having excellent heat resistance and low water absorption, which is suitable for bonding semiconductor chips and the like.

[0002]

2. Description of the Related Art Conventionally, epoxy-based thermosetting adhesives and heat-resistant hot melt adhesives have been used for connecting semiconductor lead frames and chips. In recent years, as the size of chips has increased, the percentage of chips in the package has increased. Therefore, if the adhesive or sealant absorbs moisture,
Moisture absorbed by the heat during solder expansion expands, resulting in frequent occurrence of cracks in the package. In order to prevent this phenomenon, it is necessary to lower the moisture absorption of the adhesive and to increase the heat resistance so as to withstand the temperature at the time of solder connection.

[0003]

[Patent Document 1] Japanese Patent Laid-Open No. 02-158681

[Patent Document 2] Japanese Unexamined Patent Publication No. 02-272078

[Patent Document 3] Japanese Patent Laid-Open No. 03-014890

[Patent Document 4] Japanese Patent Application Laid-Open No. 03-140328

[Patent Document 5] Japanese Patent Laid-Open No. 03-159006

[Patent Document 6] Japanese Patent Laid-Open No. 63-045051

[Patent Document 7] Japanese Patent Application Laid-Open No. 01-126331

[Patent Document 8] JP-A-63-172736

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a composite sheet having an adhesive layer having a low moisture absorption rate and a high heat resistance.

[0005]

The first invention of the present invention is as follows:
After applying a polyamic acid or polyimide varnish containing a structural unit represented by the general formula (1) or the general formula (2) and having a glass transition temperature of 250 ° C. or higher to one or both surfaces of the surface-treated heat-resistant film, It is a composite adhesive sheet in which an adhesive layer is formed by heating.

[0006]

[Chemical 9]

[0007]

[Chemical 10]

[In the general formulas (1) and (2),
R ¹ , R ² , R ³ , and R ⁴ are each independently hydrogen or an alkyl group or an alkoxy group having 1 to 4 carbon atoms, at least two of which are alkyl groups or alkoxy groups, and R ⁵ is Hydrogen or an alkyl group having 1 to 4 carbon atoms, X is —CH ₂ —, —C (CH ₃ ) ₂ —, —O.
A group represented by —, —SO ₂ —, —CO— or —NHCO—, and Ar ¹ is a tetravalent aromatic group. ]

A second invention of the present invention is to apply a varnish of a heat-resistant resin containing a constitutional unit represented by the general formula (3) to one or both surfaces of a surface-treated heat-resistant film, and then heat the adhesive to form an adhesive layer. And the resin of the adhesive layer is linked to the aromatic groups of general formula (4), general formula (5), general formula (6), general formula (7), and general formula (8). Base 10
˜90 mol% is an amide group, and the composite adhesive sheet has a glass transition temperature of 250 ° C. or higher.

[0010]

[Chemical 11]

[In the general formula (3), R⁶, R⁷,
R⁸, R⁹Are each independently hydrogen or C1-4
Alkyl group or alkoxy group, which is
At least two or more are alkyl groups or alkoxy groups
X is -CH₂ -, -C (CH ₃ )₂-, -O-,-
SO₂ A group represented by-, -CO- or -NHCO-
And Z is general formula (4), general formula (5), general formula
(6), general formula (7), general formula (8) (general formula (4),
General formula (5), general formula (6), general formula (7), general formula
Ar in (8)² Is a divalent to tetravalent aromatic group, R^TenIs water
It is an alkyl group having 1 to 4 carbon atoms. )
It is a group that is ]

[0012]

[Chemical 12]

[0013]

[Chemical 13]

[0014]

[Chemical 14]

[0015]

[Chemical 15]

[0016]

[Chemical 16]

The first invention will be described. The adhesive used in the first invention comprises a structural unit represented by the general formula (1) or the general formula (2), and is formed from a polyamic acid or polyimide varnish having a glass transition temperature of 250 ° C. or higher.

[0018]

[Chemical 17]

[0019]

[Chemical 18]

[In the general formulas (1) and (2),
R ¹ , R ² , R ³ , and R ⁴ are each independently hydrogen or an alkyl group or an alkoxy group having 1 to 4 carbon atoms, at least two of which are alkyl groups or alkoxy groups, and R ⁵ is Hydrogen or an alkyl group having 1 to 4 carbon atoms, X is —CH ₂ —, —C (CH ₃ ) ₂ —, —O.
A group represented by —, —SO ₂ —, —CO— or —NHCO—, and Ar ¹ is a tetravalent aromatic group. ]

The above-mentioned polyamic acid or polyimide is represented by the general formula (9) with an acid dianhydride.

[Chemical 19] [In the general formula (9), Y represents an amino group or an isocyanate group, and R ¹¹ , R ¹² , R ¹³ and R ¹⁴ each independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms or an alkoxy group, At least two or more of these are alkyl groups or alkoxy groups, and X is —CH _{2
-, - C (CH 3)} 2 -, - O -, - SO 2 -, - CO-
Alternatively, it is a group represented by -NHCO-. ] It synthesize | combines with the diamine or diisocyanate represented by this.

Among the compounds represented by the general formula (9), those in which Y is an amino group 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 '
-Dimethyldiphenylmethane, 4,4'-diamino-
3,3'-diethyldiphenylmethane, 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-trin-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 (3,3 ', 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'
-Tetramethyl diphenyl ether, 4,4'-diamino-3,3 ', 5,5'-tetraethyl diphenyl ether, 4,4'-diamino-3,3', 5,5'-tetra n-propyl diphenyl ether, 4, 4'-diamino-3,3 ', 5,5'-tetraisopropyldiphenyl ether, 4,4'-diamino-3,3', 5,5 '
-Tetrabutyldiphenylether, 4,4'-diamino-3,3 ', 5,5'-tetramethyldiphenylsulfone, 4,4'-diamino-3,3', 5,5'-tetraethyldiphenylsulfone, 4, 4'-diamino-
3,3 ', 5,5'-tetra-n-propyldiphenyl sulfone, 4,4'-diamino-3,3', 5,5'-tetraisopropyldiphenyl sulfone, 4,4'-diamino-3,3 ' , 5,5'-Tetrabutyldiphenylsulfone, 4,4'-diamino-3,3 ', 5,5'-tetramethyldiphenylketone, 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'-tetraisopropyldiphenylketone, 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.

Among the compounds represented by the above general formula (9), those in which Y is an isocyanate group include the diamines exemplified above in which an amino group is replaced with an isocyanate group. . General formula (9)
In Examples of the diamine used in combination with diamine represented, para-phenylenediamine, meta-phenylenediamine, meta-toluylene diamine, 4,4 '- diaminodiphenyl ether (DDE), 4,4' - diaminodiphenylmethane, 4,4 '- diamino Diphenyl sulfone, 3,3 '
- diaminodiphenyl sulfone, 4,4 '- diamino benzophenone, 3,3' - diaminobenzophenone,
1,4 - bis (4 - aminocumyl) benzene (BA
P), 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 a siloxane diamine represented by general formula (10).

[0024]

[Chemical 20] [In the general formula (10), R ¹⁵ and R ¹⁸ are divalent organic groups, R ¹⁶ and R ¹⁷ are monovalent organic groups, and m is 1 to 1
00 is an integer. ]

In formula (10, R ¹⁵ and R ¹⁸ each independently include a trimethylene group, a tetramethylene group, a phenylene group, a toluylene group, etc., and R ¹⁶ and R ¹⁷ each independently a methyl group, an ethyl group. , R ¹⁶ and R ¹⁷ may be the same or different, and in the siloxane diamine of the general formula (10), R ¹⁵ and R ¹⁸ are both trimethylene groups. , R ¹⁶ and R ¹⁷ are both methyl groups, m is 1, about 10 on average, about 20 on average, about 30 on average, 5 on average.
About 0 and about 100 on average are LP-7100, X-22-161AS, X-22-1 respectively.
61A, X-22-161B, X-22-161C and X-22-161E (all are trade names of Shin-Etsu Chemical Co., Ltd.).

Examples of the acid anhydride include pyromellitic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride (BTDA), 3,3', 4,4'-biphenyltetracarboxylic acid. Dianhydride, 2,2-bisphthalic acid hexafluoroisopropylidene dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride,
Bis (3,4-dicarboxyphenyl) sulfone dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenylsulfone 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)] bisphenylbistrimellitate dianhydride or the like is used.

Of these diamines and acid anhydrides,
The monomer is appropriately selected so that the Tg of the obtained polyimide is 250 ° C. or higher. Polyimides are obtained by thermal or chemical ring closure of polyamic acids. The varnish used in the present invention does not necessarily have to be 100% imidized, but it is preferably completely imidized.

Examples of the heat-resistant film used in the present invention include polyimide, polyamide, and engineering plastics such as polysulfone, polyphenylene sulfide, polyether ether ketone, and polyarylate, which have a glass transition temperature (T
From the viewpoint of g), water absorption and thermal expansion coefficient, a polyimide film is preferable. Tg is 250 ° C or higher, water absorption is 2% or lower,
A film having a coefficient of thermal expansion of 3 × 10 ⁻⁵ ° C. ⁻¹ or less is particularly preferable. The heat-resistant film requires surface treatment to increase the adhesive strength with the adhesive. As the surface treatment method, any treatment such as alkali treatment, chemical treatment such as silane coupling treatment, physical treatment such as sandblasting, plasma treatment, corona treatment, etc. can be used, but the most suitable treatment depends on the type of adhesive. Any suitable process may be used. Chemical treatments or plasma treatments are particularly suitable for the adhesives according to the invention. The adhesive may be polyimide alone, a mixture of polyimide and polymaleimide, or an epoxy resin, a curing agent, a curing accelerator, etc. may be added and used. Further, a filler such as ceramic powder or glass powder or a coupling agent may be added. The method for applying the polyamic acid varnish or the polyimide varnish to the heat resistant film is not particularly limited. It may be applied by any method such as a doctor blade, a knife coater or a die coater. It is also possible to apply a film through the varnish, but this is not preferred because it is difficult to control the thickness. The film coated with the adhesive is heat-treated to remove the solvent and imidize, but the heat-treatment temperature differs depending on whether it is polyamic acid or polyimide.
In the case of polyamic acid varnish, T is used for imidization.
A temperature of g or more is necessary, but in the case of imide varnish, it may be any temperature at which the solvent can be removed. In order to improve the adhesive strength between the adhesive and the heat resistant film, it is preferable to perform heat treatment at a temperature of 250 ° C. or higher.

As the adhesive used in the second invention of the present invention, a varnish of a heat-resistant resin containing a structural unit represented by the general formula (3) is applied to a heat-resistant film and then heated to form an adhesive layer. The resin of the adhesive layer is 10 of the groups linked to the aromatic groups of general formula (4), general formula (5), general formula (6), general formula (7), and general formula (8). ~
90 mol% is an amide group and has a glass transition temperature of 25
It is 0 ° C or higher.

[0030]

[Chemical 21]

{In the general formula (3), R ⁶ , R ⁷ and R
⁸ , R ⁹ are each independently hydrogen or an alkyl group or alkoxy group having 1 to 4 carbon atoms, at least two of which are alkyl groups or alkoxy groups, and X is —CH ₂ —, —C ( _{CH 3) 2 -, - O} -, -
Z is a group represented by SO ₂ —, —CO— or —NHCO—, and Z is general formula (4), general formula (5), general formula (6), general formula (7), general formula (8) ( General formula (4),
In general formula (5), general formula (6), general formula (7), and general formula (8), Ar ² is a divalent to tetravalent aromatic group, R ¹⁰ is hydrogen or an alkyl group having 1 to 4 carbon atoms. is there. ) Is a group represented by. }

[0032]

[Chemical formula 22]

[0033]

[Chemical formula 23]

[0034]

[Chemical formula 24]

[0035]

[Chemical 25]

[0036]

[Chemical formula 26]

(In the general formula (4), the general formula (5), the general formula (6), the general formula (7) and the general formula (8), Ar ² is a divalent to tetravalent aromatic group, and R ¹⁰ is hydrogen. Or an alkyl group having 1 to 4 carbon atoms). }

The above adhesive is synthesized from an acid anhydride or a dicarboxylic acid or an amide-forming derivative thereof and the same diamine or diisocyanate represented by the general formula (9) as used in the first invention. It As the diamine, the same diamine as the diamine exemplified as the diamine used in combination with the diamine represented by the general formula (9) in the first invention is used in combination. The acid anhydride used in the first invention is also used as the acid anhydride. Examples of the dicarboxylic acid or its amide-forming derivative include terephthalic acid, isophthalic acid, biphenylcarboxylic acid, phthalic acid, naphthalene dicarboxylic acid, diphenyl ether dicarboxylic acid, and the like. Examples include acid dichlorides and dialkyl esters.

A part of the diamine or dicarboxylic acid may be replaced with an aminocarboxylic acid such as aminobenzoic acid.
From these diamines, acid anhydrides and dicarboxylic acids, the monomer is appropriately selected so that the Tg of the obtained resin is 250 ° C. or higher. When polyimide and polyamide are mixed, the Tg of the adhesive after mixing should be 250 ° C. or higher. The amide group is 10 to 90 mol%, preferably 20 to 70 mol%, and more preferably 30 to 50 mol% of the total of the groups of the general formulas (4) to (8). If it is less than 10%, the adhesive strength will be small, and if it is more than 90%, the water absorption will be large. Polyimides are obtained by thermal or chemical ring closure of polyamic acids. The varnish used in the present invention does not necessarily have to be 100% imidized, but it is preferably completely imidized. The adhesive may be polyamide imide alone, a mixture of polyimide and polyamide, or an epoxy resin, a curing agent, a curing accelerator, etc. may be added and used. Further, a filler such as ceramic powder or glass powder or a coupling agent may be added.

The method of applying the heat resistant adhesive varnish to the heat resistant film is not particularly limited. It may be applied by any method such as a doctor blade, a knife coater or a die coater. It is also possible to apply a film through the varnish, but this is not preferred because it is difficult to control the thickness. The film coated with the adhesive is heat-treated to remove the solvent and imidize, but the heat-treatment temperature differs depending on whether it is a polyamic acid varnish or a polyimide varnish. In the case of a polyamic acid varnish, a temperature of Tg or higher is required for imidization, but in the case of an imide varnish, it may be a temperature at which the solvent can be removed. In order to improve the adhesive strength between the adhesive and the heat resistant film, it is preferable to perform heat treatment at a temperature of 250 ° C. or higher.

The composite adhesive sheets obtained in the first and second aspects of the present invention are the adherends such as lead frames, ceramic plates, metal plates, metal foils, plastic films, plastic plates and laminated plates. Or by sandwiching it between the adherends and heating and pressurizing it at a temperature equal to or higher than the melting temperature of the adhesive. FIG. 1 is a cross-sectional view in which an LSI chip 2 and a lead frame 3 are adhered by the composite adhesive sheet of the present invention, 5 is a wire and 6 is a sealing material.

[0042]

Example 1 In a four-necked flask equipped with a stirrer, a thermometer, a nitrogen gas introduction tube, and a calcium chloride tube, 4,4'-diamino-3,
3.66 g (10 mmol) of 3 ', 5,5'-tetraisopropyldiphenylmethane (IPDDM) and 28.3 g of N, N-dimethylformamide (DMF) were added and dissolved. Next, bisphenol A bis trimellitate dianhydride (B
After adding 5.76 g (10 mmol) of ABT little by little, the reaction was carried out for 1 hour while cooling so as not to exceed 5 ° C. and then for 6 hours at room temperature to synthesize a polyamic acid.
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 synthesize a polyimide. The obtained polyimide varnish was poured into water, and the obtained precipitate was separated, pulverized and dried to obtain a polyimide powder. This polyimide powder was added to DMF at 0.
It was dissolved at a concentration of 1 g / dl, and the reduced viscosity when measured at 30 ° C. was 0.57 dl / g. Further, a solubility test was conducted by adding this polyimide powder to various organic solvents to a concentration of 5 wt% and observing the dissolved state at room temperature. As a result, the polyimide powder is
It was soluble in MF, N-methylpyrrolidone (NMP), methylene chloride, dioxane, THF and toluene. Further, this polyimide powder was dissolved in DMF, and the obtained varnish was cast on a glass plate. After drying at 100 ° C. for 10 minutes, it was peeled off, fixed on an iron frame and dried at 250 ° C. for 1 hour to obtain a film. Using the film thus obtained, a load of 25 kg / cm was applied by a penetration method.
^2. The glass transition temperature (Tg) of the polyimide was 261 ° C. when the temperature rising rate was 10 ° C./min. The thermal decomposition temperature was 405 ° C. The water absorption rate when the film was immersed in water at 25 ° C. for 24 hours was 0.3%.
Further, when the obtained film was bent at an angle of 180 degrees and a flexibility test was conducted, the film did not crack and showed good flexibility. After coating NMP varnish of polyimide on plasma-treated Upilex S film, 1
A composite sheet was obtained by drying at 00 ° C for 10 minutes and further at 300 ° C for 10 minutes. This composite sheet is stacked on 42 alloy and 3
After being soaked at 50 ° C. and 3 MPa for 5 seconds, the 90-degree peeling strength was measured and found to be 0.8 kN / m. A semiconductor chip was packaged as shown in FIG. 1 using this composite sheet, subjected to moisture absorption treatment under conditions of 85 ° C. and 85% RH for 48 hours, and then immersed in a solder bath at 260 ° C. However, no crack was generated.

Example 2 3.58 g (10 mmol) of bis (3,4-dicarboxyphenyl) sulfone dianhydride (DSDA), IPDD
M 1.83 g (5 mmol), 2,2-bis [4-
(4-Aminophenoxy) phenyl] propane (BAP
P) Example 1 except that 2.05 g (5 mmol) is used.
A polyamic acid varnish was obtained in the same manner as. This polyamic acid varnish was obtained in the same manner as in Example 1 to obtain a polyimide powder. The reduced viscosity was 1.39 dl / g, the Tg was 268 ° C, and the thermal decomposition temperature was 410 ° C. The water absorption rate was 0.7%. Using the above polyamic acid varnish, 100 ° C. 10
A composite sheet was obtained in the same manner as in Example 1 except that the heat treatment was performed at 300 ° C. for 15 minutes. Adhesion with 42 alloy is 1.2
kN / m, and the semiconductor package obtained in the same manner as in Example 1 did not generate cracks by the solder treatment after moisture absorption.

Example 3 3.22 g of 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride (BTDA) instead of BABT
(10 mmol), NMP 20.6 g instead of DMF
A polyamic acid varnish was obtained in the same manner as in Example 1 except that was used. 10 g of xylene was added to this varnish and heated at 180 ° C. for 5 hours to obtain a polyimide varnish. The reduced viscosity was 0.48 dl / g, the Tg was 300 ° C, and the thermal decomposition temperature was 405 ° C. The water absorption rate was 1.0%. After the alkali treatment, the above-mentioned polyimide varnish is applied to the Kapton film subjected to the silane coupling treatment, and the temperature is 100 ° C. 10
Min, 275 ° C. and heat treated for 10 minutes to obtain a composite sheet. 42
The adhesive strength with the alloy was 0.92 kN / m, and the semiconductor package obtained in the same manner as in Example 1 did not generate cracks due to the solder treatment after absorbing moisture.

Example 4 5.76 g (10 mmol) BABT, IPDDM
A polyimide powder was obtained in the same manner as in Example 1 except that 2.38 g (6.5 mmol) and 0.43 g (3.5 mmol) of metatoluylenediamine (MTDA) were used. The reduced viscosity was 0.61 dl / g, the Tg was 275 ° C, and the thermal decomposition temperature was 415 ° C. The water absorption rate was 0.5%. After coating the NMP varnish of the above-mentioned polyimide on an alkali-treated Upilex S film, 10 minutes at 100 ° C.,
Further, it was dried at 300 ° C. for 10 minutes to obtain a composite sheet. Four
The adhesive strength with the 2-alloy was 0.85 kN / m, and the semiconductor package obtained in the same manner as in Example 1 was free from cracks due to the solder treatment after moisture absorption.

Example 5 3.58 g (10 mmol) of DSDA, IPDDM
0.92 g (2.5 mmol), BAPP 3.08 g
A polyimide powder was obtained in the same manner as in Example 3 except that (7.5 mmol) was used. Reduced viscosity is 1.16dl / g, T
The g was 256 ° C and the thermal decomposition temperature was 440 ° C. The water absorption rate was 1.2%. After coating the above DMAc varnish of polyimide on a plasma-treated Upilex S film, the temperature is 100 ° C. for 10 minutes, and further 250 ° C. for 10 minutes.
Minute drying was performed to obtain a composite sheet. The adhesive strength with the 42 alloy was 1.35 kN / m, and the semiconductor package obtained in the same manner as in Example 1 did not cause cracks due to the solder treatment after moisture absorption.

Comparative Example 1 3.58 g (10 mmol) of DSDA, IPDDM
0.55 g (1.5 mmol), m-APPS 3.6
A polyimide powder was obtained in the same manner as in Example 1 except that 7 g (8.5 mmol) was used. Reduced viscosity is 0.65dl /
The g and Tg were 232 ° C and the thermal decomposition temperature was 455 ° C.
The water absorption rate was 2.2%. NMP of the above polyimide
After coating the varnish on the plasma-treated Upilex S film, 10 minutes at 100 ° C and 1 hour at 300 ° C
It was dried for 0 minutes to obtain a composite sheet. The adhesive strength with 42 alloy was 1.05 kN / m. The semiconductor package obtained in the same manner as in Example 1 had cracks due to the solder treatment after moisture absorption.

Comparative Example 2 4.10 g (10 mmol) of BAPP was added to DMF 2
Dissolve in 4.5 g, 2.02 g of triethylamine (2
(0 mmol), and then 2.03 g (10 mmol) of isophthalic acid chloride was added little by little while cooling to 5 ° C or lower. After reacting at 5 ° C or lower for 5 hours, a polyamide powder was obtained in the same manner as in Example 1. The reduced viscosity is 0.
50 dl / g and Tg were 219 degreeC and the thermal decomposition temperature was 425 degreeC. The water absorption rate was 2.2%. After coating the NMP varnish of the above polyamide on a plasma-treated Upilex S film, 10 minutes at 100 ° C., and further 30 minutes
A composite sheet was obtained by drying at 0 ° C. for 10 minutes. The adhesive strength with 42 alloy was 1.55 kN / m. The semiconductor package obtained in the same manner as in Example 1 had cracks due to the solder treatment after moisture absorption.

Synthesis Example 1 4,4'-diamino-3, was added to a four-necked flask equipped with a stirrer, a thermometer, a nitrogen gas inlet tube, and a calcium chloride tube.
3.66 g (10 mmol) of 3 ', 5,5'-tetraisopropyldiphenylmethane (IPDDM) and 28.3 g of N, N-dimethylformamide (DMF) were added and dissolved. Next, bisphenol A bis trimellitate dianhydride (B
After adding 5.76 g (10 mmol) of ABT little by little, the reaction was carried out for 1 hour while cooling so as not to exceed 5 ° C. and then for 6 hours at room temperature to synthesize a polyamic acid.
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 synthesize a polyimide. The obtained polyimide varnish was poured into water, and the obtained precipitate was separated, pulverized and dried to obtain a polyimide powder. This polyimide powder was added to DMF at 0.
It was dissolved at a concentration of 1 g / dl, and the reduced viscosity when measured at 30 ° C. was 0.57 dl / g. Further, this polyimide powder was dissolved in DMF, and the obtained varnish was cast on a glass plate. After drying at 100 ° C. for 10 minutes, it was peeled off, fixed on an iron frame and dried at 250 ° C. for 1 hour to obtain a film. Using the film thus obtained, a load of 25 kg / cm ² and a heating rate of 1 were measured by a penetration method.
Glass transition temperature (Tg) of polyimide under conditions of 0 ° C / min
Was 261 ° C. Pyrolysis temperature is 40
It was 5 ° C. The water absorption rate when the film was immersed in water at 25 ° C. for 24 hours was 0.3%.

Synthesis Example 2 4,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) 4.10 g (10 mmol)
Was dissolved in 24.5 g of DMF, and triethylamine 2.0 was added.
After adding 2 g (20 mmol), 2.03 g (10 mmol) of isophthaloyl chloride was added little by little while cooling to 5 ° C or lower. After reacting at 5 ° C. or lower for 5 hours, a polyamide powder was obtained in the same manner as in Synthesis Example 1. Reduced viscosity is 0.50 dl / g, Tg is 219 ° C, thermal decomposition temperature is 4
It was 25 ° C. The water absorption rate was 2.2%.

Synthesis Example 3 1.74 g (7) of 4,4'-diaminodiphenyl sulfone
DM) and BAPP 1.23 g (3 mmol)
Dissolve in 20 g of F, 2.02 g of triethylamine (20
Then, 2.03 g (10 mmol) of isophthalic acid chloride was added little by little while cooling to 5 ° C. or lower. After reacting at 5 ° C. or lower for 5 hours, a polyamide powder was obtained in the same manner as in Synthesis Example 1. Reduced viscosity is 0.45
dl / g and Tg were 260 degreeC and the thermal decomposition temperature was 435 degreeC. The water absorption rate was 2.5%.

Example 6 A DMF varnish prepared by mixing 85 wt% of the polyimide of Synthesis Example 1 and 15 wt% of the polyamide of Synthesis Example 2 was applied on a plasma-treated Upilex S film, and then 100
A composite sheet was obtained by drying at 10 ° C for 10 minutes and further at 250 ° C for 10 minutes. Stack this composite sheet on 42 alloy for 350
After being soaked at 3 ° C. for 3 seconds at 90 ° C., the 90-degree peel strength was measured and found to be 1.2 kN / m. In addition,
Tg of blend film is 255 ℃, water absorption is 0.6%
Met. A semiconductor chip was packaged as shown in FIG. 1 using this composite sheet, subjected to moisture absorption treatment under conditions of 85 ° C. and 85% RH for 48 hours, and then immersed in a solder bath at 260 ° C. However, no crack was generated.

Comparative Example 3 A composite sheet was obtained in the same manner as in Example 1 except that the polyamide DMF varnish of Synthesis Example 2 was used. The adhesive strength with 42 alloy is 1.
It was 55 kN / m. The semiconductor package obtained in the same manner as in Example 1 had cracks due to the solder treatment after moisture absorption.

Comparative Example 4 A composite sheet was obtained in the same manner as in Example 1 except that the polyimide DMF varnish of Synthesis Example 1 was used. However, the adhesive strength to the Upilex film was weak, and sometimes peeling occurred.

Example 7 An NMP varnish prepared by mixing 60 wt% of the polyimide of Synthesis Example 1 and 40 wt% of the polyamide of Synthesis Example 3 was used.
A composite sheet was obtained in the same manner as in Example 1 except that the heat treatment was performed at 10 ° C for 10 minutes, and further at 300 ° C for 10 minutes. The adhesive strength of this composite sheet with 42 alloy was 1.6 kN / m. The Tg of the blend film was 260 ° C., and the water absorption rate was 1.1%. Example 1 using this composite sheet
In the semiconductor package obtained in the same manner as above, no crack was generated even by the solder treatment after moisture absorption.

Example 8 1.83 g (5 mmol) IPDDM, BAPP2.0
5 g (5 mmol), trimellitic anhydride chloride 0.
64 g (3 mmol), triethylamine 0.30 g
(3 mmol), except that 30 g of NMP was used, Synthesis Example 2
A polyamic acid varnish was obtained in the same manner as. To this varnish, 2.51 g (7 mmol) of bis (3,4-dicarboxyphenyl) sulfone dianhydride (DSDA) was added little by little at 5 ° C or lower, and then reacted at 5 ° C or lower for 5 hours. Thereafter, acetic anhydride and pyridine were added to obtain a polyamideimide powder in the same manner as in Synthesis Example 1. The polyamideimide had a reduced viscosity of 0.65 dl / g, a Tg of 257 ° C. and a thermal decomposition temperature of 385 ° C. The water absorption rate was 1.0%. After the alkali treatment, a silane coupling-treated Kapton film was coated with a varnish prepared by dissolving the above polyamideimide in DMAc, followed by 100 ° C. for 10 minutes and 275 ° C.
Heat treatment was performed for minutes to obtain a composite sheet. The adhesive strength with the 42 alloy was 1.4 kN / m, and the semiconductor package obtained in the same manner as in Example 1 was free from cracks due to the solder treatment after moisture absorption.

[0057]

Since the composite sheet of the present invention has a low moisture absorption rate and high heat resistance, it is effective in improving the reliability of the semiconductor package.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a usage state of a composite sheet.

[Explanation of symbols]

1. Composite sheet 2. LSI chip 3. Lead frame

Claims (2)

[Claims] 1. A polyamic acid or polyimide varnish containing a structural unit represented by the general formula (1) or (2) on one or both sides of a surface-treated heat-resistant film and having a glass transition temperature of 250 ° C. or higher. After applying, a composite adhesive sheet in which the adhesive layer is formed by heating. [Chemical 1] [Chemical 2] [In General Formula (1) and General Formula (2), R ¹ , R ² , R
³ , R ⁴ are each independently hydrogen or an alkyl group or alkoxy group having 1 to 4 carbon atoms, at least two of which are alkyl groups or alkoxy groups, and R ⁵ is hydrogen or 1 to 4 carbon atoms. an alkyl group, X is _{-CH 2 -, - C (CH} 3) 2 -, - O -, -
Ar ² is a group represented by SO ₂ —, —CO— or —NHCO—, and Ar ¹ is a tetravalent aromatic group. ] 2. A varnish of a heat-resistant resin containing a structural unit represented by the general formula (3) is applied to one or both surfaces of a surface-treated heat-resistant film and then heated to form an adhesive layer. The resin of the adhesive layer is 10 to 90 moles of the group connected to the aromatic group of general formula (4), general formula (5), general formula (6), general formula (7), and general formula (8). % Is an amide group and has a glass transition temperature of 250 ° C. or higher. [Chemical 3] {In the general formula (3), R ⁶ , R ⁷ , R ⁸ and R ⁹ are each independently hydrogen or an alkyl group or an alkoxy group having 1 to 4 carbon atoms, at least two of which are alkyl groups or an alkoxy group, X is -CH _{2
-, - C (CH 3)} 2 -, - O -, - SO 2 -, - CO-
Or a group represented by -NHCO-, and Z is represented by general formula (4), general formula (5), general formula (6), general formula (7),
In general formula (8) (general formula (4, general formula (5), general formula (6), general formula (7), general formula (8), Ar ² is a divalent to tetravalent aromatic group, R ¹⁰ is Hydrogen or an alkyl group having 1 to 4 carbon atoms). [Chemical 5] [Chemical 6] [Chemical 7] [Chemical 8]