JP3516473B2 - Heat-resistant adhesive film for printed circuit boards - Google Patents

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 film for a printed circuit board, and in particular, a novel heat-resistant adhesive film for a printed circuit board, which can be subjected to low-temperature pressure bonding, has a low expansion coefficient after thermocompression bonding, and has excellent dielectric properties. It is about.

[0002]

2. Description of the Related Art As a printed wiring board, a board made of paper-phenol resin, glass fiber-epoxy resin, or a polyimide film, a polyethylene terephthalate film and a metal foil are conventionally used.

Further, in recent years, in printed wiring boards used in the fields of electric / electronic equipment and precision equipment, the wiring occupying area has become smaller, so that the demand for multilayer wiring boards is ever increasing. Various adhesives or adhesive films are used in the process of laminating the printed wiring boards to form a multilayer wiring board or compounding different circuit materials.

As such an adhesive, a prepreg-like adhesive in which a woven fabric such as glass fiber is impregnated with an epoxy type or bismaleimide type resin is known. But,
This has problems such as insufficient flexibility and poor dimensional stability. Further, conventionally, adhesives such as acrylonitrile butadiene rubber / phenol resin, phenol resin / butyral resin, and acrylonitrile butadiene rubber / epoxy resin have been proposed (JP-A-4-29393).
JP-A-4-36366 and JP-A-4-41
581). However, these adhesives are heat resistant,
Insufficient chemical resistance and durability, large thermal deterioration, insufficient solder heat resistance after moisture absorption, and workability such as smearing during drilling for through hole formation. The points were not enough either.

Further, since these adhesives have a large expansion coefficient of the resin after thermocompression bonding, they are sufficient in terms of reliability such as easy peeling at the interface between the adherend and the adhesive at the through holes during thermal shock. Was not.

As a means for solving these various problems,
A polyimide adhesive having excellent heat resistance has been proposed.
For example, the thermoplastic polyimide adhesive disclosed in USP 4,543,295 is known. However, in order to obtain satisfactory strength, it is necessary to use such a polyimide in order to bond substrates such as copper or a polyimide film to each other.
Since a thermocompression bonding temperature of 50 ° C. or higher is required, there is a difficulty in practical use.

As a polyimide-based adhesive having excellent adhesive strength, Japanese Unexamined Patent Publication (Kokai) No. 52-91082 discloses a film made of polyamideimide and an epoxy resin as an adhesive for producing a copper clad film for flexible printed wiring boards. Has been done. However, when such a film is used for adhering surfaces on which circuits are formed, such as in the production of multilayer printed wiring boards, the fluidity is insufficient, so that the circuit surface is not sufficiently filled and the solder bath It is not possible to obtain sufficient heat resistance against.

Therefore, as a multi-layer printed circuit board adhesive and cover lay film adhesive, low-temperature pressure bonding at 250 ° C. or lower is possible, and further adhesive strength, chemical resistance, heat resistance, moisture absorption solder heat resistance, dimensions during wiring processing. There has been a strong demand for materials having excellent stability and the like.

[0009]

DISCLOSURE OF THE INVENTION The present invention provides a heat-resistant polyimide-based printed circuit board having excellent fluidity, heat resistance, solder heat resistance after moisture absorption, workability, dielectric properties, etc. under thermocompression bonding conditions of 200 ° C. or less. It is intended to provide an adhesive film.

[0010]

The present invention comprises an epoxy group and
Aromatic diamine containing reactive functional groups
Aromatic diamines and diaminosiloxanes and tetracals
Having a silicon unit by reacting boric acid dianhydride
Obtain the polyimide resin (A) and use this polyimide resin.
(A) 70 to 99 wt% epoxy resin (B) 1 to 30 wt%
Is mixed in the presence of a solvent to give a resin solution.
After coating on the substrate, dry and peel from the substrate
A glass transition point of 60 to 170 ° C., a tensile rupture strength of the film after curing is 4 to 20 kg / mm ² , and a tensile elastic modulus of 100 to 300 kg / mm ² is a single layer polyimide system. A method for producing a heat-resistant adhesive film for a printed circuit board.

As a result, sufficient adhesiveness, heat resistance, solder heat resistance after moisture absorption, dimensional stability during wiring processing, adhesive fillability into circuits, and through hole reliability under thermocompression bonding conditions of 200 ° C. or less. (Smear removal during punching, heat shock resistance after lamination), etc. can be manufactured.

If the glass transition point exceeds 170 ° C., it is 2
Since the fluidity is insufficient under thermocompression bonding conditions of 00 ° C or lower, the filling of irregularities on the circuit surface is not sufficient, and the heat resistance to the solder bath is insufficient. It is possible, but the heat resistance and chemical resistance are poor,
Insufficient solder heat resistance after moisture absorption.

The adhesive film after curing has a tensile breaking strength of 2
Exceeding 0 kg / mm ² or tensile modulus of 300
If it exceeds kg / mm ² , the circuit surface irregularities will not be sufficiently filled, and if the tensile breaking strength is less than 4 kg / mm ² or the tensile modulus is less than 300 kg / mm ² , smearing during drilling will occur. Occurs remarkably, and the reliability of the obtained through hole is poor.

Further, if the linear expansion coefficient of the cured adhesive film is less than 5 × 10 ^-5 / ° C, the filling of irregularities on the circuit surface is not sufficient, and if it exceeds 15 × 10 ^-5 / ° C, the wiring is processed. The dimensional stability is low and the through hole reliability is poor.

Furthermore, if the dielectric constant of the adhesive film after curing exceeds 3.5 at 1 MHz or the dielectric loss tangent exceeds 0.005, problems such as delay of circuit response speed in multi-layer and high-density wiring board occur. Easier to do.

The resin of the heat-resistant adhesive film for a polyimide-based printed circuit board of the present invention is obtained, for example, by mixing 70 to 99% by weight of a polyimide resin having a silicon unit and 1 to 30% by weight of an epoxy resin. Also,
The composition of the present invention is also included in the scope of the present invention as long as the film has the above-mentioned characteristics even if the composition is other than the above, as long as it is a heat-resistant adhesive film for polyimide-based printed circuit boards.

In the present invention, as the polyimide resin having a silicon unit, it is desirable to use a solvent-soluble polyimide having good film formability. As an example that is preferably used as a solvent-soluble polyimide, the following general formula (1)

[Chemical 1] And the following general formula (2)

[Chemical 2] It is an aromatic polyimide resin represented by.

The polyimide resin having the repeating units represented by the above general formulas (1) and (2) can be obtained by reacting diaminosiloxane and aromatic diamine with tetracarboxylic dianhydride.

Specific examples of the tetracarboxylic acid dianhydride include 3,3 ', 4,4'-diphenyl ether tetracarboxylic acid dianhydride and 3,3', 4,4'-diphenylsulfone tetracarboxylic acid dianhydride. Things, 3,3 ', 4,4'
-Benzophenone tetracarboxylic dianhydride, 2,
2 ', 3,3'-benzophenone tetracarboxylic acid dianhydride can be mentioned. In addition, as a part of the tetracarboxylic dianhydride component, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, Pyromellitic dianhydride,
1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 3, 4,6,7-anthracene tetracarboxylic acid dianhydride, 1,2,7,8-phenanthrene tetracarboxylic acid dianhydride, 4,4 ′-(hexafluoroisopyridene) phthalic acid dianhydride and the like can be mentioned. To be

The diaminosiloxane is represented by the following general formula (4)

[Chemical 3] The diaminosiloxane represented by is used. As a specific example, preferably

[Chemical 4] Etc.

The average n number of these diaminosiloxanes is preferably in the range of 1-20, more preferably 5-15. By introducing a silicon unit into the polyimide resin by using these diaminosiloxanes, it is possible to impart fluidity at the time of thermocompression bonding and improve the filling property on the printed circuit board surface.

Specific examples of aromatic diamines include:
m-phenylenediamine, p-phenylenediamine,
4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylmethane, benzidine, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4 ' -Diaminodiphenyl ether, 3,3 '
-Diaminodiphenyl ether, 4,4'-diamino-
Examples thereof include p-terphenyl, but for the purpose of improving solubility in organic solvents, 2,2-bis (3-aminophenoxyphenyl) propane, 2,2-bis (4-aminophenoxyphenyl) propane, 3, 3-bis (3
-Aminophenoxyphenyl) sulfone, 4,4-bis (3-aminophenoxyphenyl) sulfone, 3,3-
Bis (3-aminophenoxyphenyl) sulfone, 4,
4-bis (4-aminophenoxyphenyl) sulfone,
2,2-bis (3-aminophenoxyphenyl) hexafluoropropane, 2,2-bis (4-aminophenoxyphenyl) hexafluoropropane, 1,4-bis (4-aminophenoxy) benzene, 4,4- ( p-phenylene diisopropylidene) bisaniline, 4,4-
A diamine having three or more aromatics such as (m-phenylenediisopropylidene) bisaniline can be used.

Further, the following general formula (3) having a functional group reactive with an epoxy resin in a part of the aromatic diamine

[Chemical 5] It is also possible to blend a diamine represented by

Examples of aromatic diamines are 2,5-diaminophenol, 3,5-diaminophenol, 4,
4 '-(3,3'-dihydroxy) diaminobiphenyl, 4,4'-(2,2'-dihydroxy) diaminobiphenyl, 2,2'-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, 3, 3 ', 4,
4'-biphenyltetraamine, 3,3 ', 4,4'-
Tetraaminodiphenyl ether, 4,4 ′-(3,
3′-dicarboxy) diphenylamine, 3,3′-dicarboxy-4,4′-diaminodiphenyl ether and the like can be mentioned, with 4,4 ′-(3,3 ′ being particularly preferred.
-Dihydroxy) diphenylamine, 4,4 '-(2,
2'-dihydroxy) diphenylamine. When these aromatic diamines are used, they react with the epoxy resin during thermocompression bonding to form a crosslinked structure, so that the adhesive strength and chemical resistance of the heat-resistant adhesive of the present invention can be further improved.

The polyimide resin is prepared by reacting the above-mentioned diaminosiloxane and aromatic diamine with tetracarboxylic dianhydride in a solvent to form a precursor resin and then subjecting it to ring closure by heating to give the above-mentioned general formulas (1) and (2). A polyimide resin having the repeating unit represented can be produced. At this time, the constitutional ratio of the repeating units represented by the general formulas (1) and (2) is (1) / (2) = 50/50 to 10/90.
It is preferably in the range of.

Examples of the epoxy resin include bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4'-biphenol and 2,2 '.
-Phenols such as biphenol, hydroquinone, resorcin, or tris (4-hydroxyphenyl)
Trivalent or higher phenols such as methane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, phenol novolac, o-cresol novolac, halogenated phenols or halogenated bisphenols such as tetrabromobisphenol A There is a glycidyl ether compound derived from

When the above-mentioned epoxy resin is used, an epoxy resin curing agent may be added for the purpose of promoting curing. Specific examples of the epoxy resin curing agent include phenol novolac, o-cresol novolac, phenol resole, diethylenetriamine, pyromellitic dianhydride, and phthalic anhydride.

In addition to the above-mentioned components, conventionally known curing accelerators, coupling agents, fillers, pigments and the like may be appropriately blended.

The heat-resistant adhesive of the present invention is used after being formed into a film, but it is possible to use a conventionally known method. As a preferable molding method, a resin solution is coated on a substrate such as a metal foil, a polyester film, or a polyimide film by a conventionally known method, dried, and then peeled from the substrate for the printed circuit board of the present invention. It can be used as a heat resistant adhesive film.

Typical solvents used in the film forming step are N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, N,
N-dimethylmethoxyacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone and other amide solvents,
Tetrahydrofuran, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dioxane, γ-butyrolactone, xylenol, chlorophenol, phenol, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, toluene, xylene, methyl ethyl ketone, and other ethers, alcohol solvents. be able to. Further, as the solvent at the time of forming the film, the solvent used at the time of producing the polyimide resin may be used as it is.

The methods and conditions for measuring various characteristics of the heat resistant adhesive film of the present invention are described below. The thickness of the adhesive film is 50 μm. (1) Glass transition temperature measuring device: thermomechanical analyzer (Seiko Denshi Kogyo Co., Ltd.)
Made) test piece: width 2mm, length 30mm (distance between grips 15
mm) Measuring conditions: The thermal expansion amount of the test piece in the lengthwise direction is measured under the conditions of a load of 2 g and a heating rate of 5 ° C./min, and the inflection point is defined as the glass transition temperature.

(2) Tensile breaking strength measuring device: Tensile tester STOROGRAPH-R1 (manufactured by Toyo Seiki Co., Ltd.) Test piece: temperature 180 ° C. ± 5 ° C., pressure 25 ± 2 kg / mm
^2. Thermo-compression bonded by hydropressing for 60 minutes. Width 12.5 mm, length 120 mm (distance between grips 101.6 mm) Measurement conditions: room temperature crosshead speed 25 mm / mi
A load is applied to the test piece at n, and the load at the time when the test piece breaks is measured. The value obtained by dividing the measured load by the cross-sectional area (0.31 mm ² ) of the test piece is taken as the tensile breaking strength.

(3) Tensile elastic modulus Measured with the same device, test piece and method as the tensile breaking strength,
The value obtained by dividing the difference in stress due to the original average cross-sectional area between two points on the straight line from the first straight line portion of the load-deflection curve by the difference in strain between the same two points is taken as the tensile elastic modulus.

(4) Linear expansion coefficient measuring device: thermomechanical analyzer (Seiko Denshi Kogyo Co., Ltd.)
Made) test piece: temperature 180 ° C ± 5 ° C, pressure 25 ± 2 kg / mm
^2. Thermo-compression bonded by hydropressing for 60 minutes. 5mm square size. Measurement conditions: The thermal expansion amount in the thickness direction of the test piece is measured under the conditions of a load of 2 g and a heating rate of 5 ° C./min, and the difference in the thermal expansion amount between the two points up to the inflection point is the same two points. The value obtained by dividing by the temperature difference between them is the coefficient of linear expansion.

(5) Dielectric constant measuring device: TR-1100 type dielectric loss automatic measuring device (manufactured by Ando Electric Co., Ltd.) Test piece: temperature 180 ° C. ± 5 ° C., pressure 25 ± 2 kg / mm
^2. Using silver paste on both sides of the adhesive film thermocompression bonded by hydropressing for 60 minutes according to JIS
Printed electrode pattern of C-6481. Measurement conditions: temperature 23 ± 3 ° C, relative humidity 5 as pretreatment
After standing in a 0 ± 5% room for 24 hours, the dielectric constant at 1 MHz is measured.

(6) Dielectric loss tangent The dielectric loss tangent is measured by the same device, test piece and method as the dielectric constant.

(7) Adhesive strength measuring device: Tensile tester STOROGRAPH-M1 (manufactured by Toyo Seiki Co., Ltd.) Test piece: temperature 180 ° C. ± 5 ° C., pressure 25 ± 2 kg / mm
² , Adhering material by hydropressing under conditions of time 60 minutes /
Adhesive film / adhered material thermocompression bonded. (Adhering material: Copper foil 35 μm, polyimide film 25 μm) Width 10 mm, length 100 mm Measurement conditions: After fixing the test piece to a stainless steel plate with a thickness of 2 mm with double-sided tape, pull it in the direction of 180 degrees at a speed of 50 mm / min. The peeling force is defined as the adhesive strength.

(8) Solder heat resistance test piece: temperature 180 ° C. ± 5 ° C., pressure 25 ± 2 kg / mm
² , Adhering material by hydropressing under conditions of time 60 minutes /
Adhesive film / adhered material thermocompression bonded. (Substrate: Copper foil 35 μm, Polyimide film 25 μm) Size 25 ± 1 mm square Measurement conditions: After thermocompression bonding, temperature 40 ± 3 ° C., relative humidity 90 ±
After being left to stand in a 5% room for 24 hours, each test piece is immersed in a solder bath at a pitch of 220 ° C. to 10 ° C. for 60 seconds, and the upper limit temperature at which foaming or peeling does not occur is measured.

(9) Fillability test piece: temperature 180 ° C. ± 5 ° C., pressure 40 ± 2 kg / mm
^2. Thermocompression-bonded by hydropressing under the following conditions for 60 minutes. Single-sided copper-clad laminate / Adhesive film / Single-sided copper-clad laminate Single-sided copper-clad laminate (Matsushita Electric Works FR-4, R1761;
Copper 35μm, substrate 100μm line width 0.1mm, line spacing 1mm
The circuit is formed by, and the patterns are laminated so that the patterns face each other at right angles via an adhesive film. Size 100 ± 1 mm square Measurement condition: After thermocompression bonding, the degree of filling the circuit is determined by an optical microscope (Nikon Co., HFX- Observe in II).

(10) Drillability test piece: temperature 180 ° C. ± 5 ° C., pressure 40 ± 2 kg / mm
^2. Thermocompression-bonded by hydropressing under the following conditions for 60 minutes. Single-sided copper-clad laminate / adhesive film / double-sided copper-clad laminate / adhesive film / single-sided copper-clad laminate Here, single-sided copper-clad laminate (Espanex (trade name) copper 18 μm manufactured by Nippon Steel Chemical Co., Ltd., Resin 25 μm) Double-sided copper clad laminate (Nippon Steel Chemical Co., Ltd. Espanex (trade name) copper 18 μm, resin 50 μm) Size 100 ± 1 mm square Measurement condition: 0.3 mmφ drill (made by Union Tool,
UC type) is used to make 1000 holes, and the degree of generation of chips and the like in the cross section of the through hole is determined by a scanning electron microscope (S510 type,
Observed by Hitachi, Ltd.

(11) Through-hole thermal shock reliability measuring device: Through-hole reliability tester (PH-500
C, manufactured by Matsushita Electric Works, Ltd.) Test piece: A circuit formed by a test pattern defined in JIS C-5012 and thermocompression bonded under the same configuration and conditions as the through hole punchability. Hole diameter: 0.3 mmφ, number of holes: 289 holes, plating thickness: 18 ± 2 μm Measurement conditions: shown in Table 1 below.

[0042]

[Table 1]

After the test piece was treated at 105 ° C. for 1 hour, →
→ is one cycle and the through-hole resistance is measured.
The defect was judged when the wire was broken (resistance value was 10Ω or more) at high temperature, and the number of cycles until the wire was broken was defined as the through-hole thermal shock reliability.

[0044]

EXAMPLES The present invention will be described in more detail with reference to the following examples. The abbreviations used in this example indicate the following compounds. ODPA: 3,3 ′, 4,4′-diphenyl ether tetracarboxylic acid dianhydride DSDA: 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic acid dianhydride BTDA: 3,3 ′, 4,4 ′ -Benzophenone tetracarboxylic acid dianhydride 6FDA: 4,4 '-(hexafluoroisopyridene)
Phthalic acid dianhydride PSX-A: average molecular weight 740 diaminosiloxane PSX-B: average molecular weight 1240 diaminosiloxane PSX-C: average molecular weight 2000 diaminosiloxane BAPP: 2,2'-bis (4-aminophenoxyphenyl) Propane BAPSM: Bis (3-aminophenoxyphenyl) sulfone BisAM: 4,4- (m-phenylenediisopropylidene) bisaniline BisAF-A: 2,2- (4-aminophenoxyphenyl) hexafluoropropane o-DAP: 2 , 5-Diaminophenol o-HAB: 4,4 '-(3,3'-dihydroxy) diaminobiphenyl m-HAB: 4,4'-(2,2'-dihydroxy) diaminobiphenyl DGEBA: Bisphenol A type epoxy resin (190
g / eq) o-CNB: o-cresol novolac type epoxy resin (275 g / eq) BCNB: polyglycidyl ether of brominated phenol novolac (200 g / eq)

Example 1 37.14 g of ODPA was placed in a 1-liter separable flask.
(0.11 mol), N-methyl-2-pyrrolidone 200
g and diethylene glycol dimethyl ether 200 g
Was added and mixed well at room temperature. Next, PSX-A31.
56 g (n = 8.4, 0.035 mol) was added dropwise using a dropping funnel, the reaction solution was ice-cooled with stirring, and BAP was added.
P30.3g (0.075mol) was added and the mixture was allowed to stand at room temperature for 2
After stirring for a time, polyamic acid was obtained. This polyamic acid solution was heated to 190 ° C., heated and stirred for 20 hours, and ring-closed while azeotroping diethylene glycol dimethyl ether and condensed water to obtain a polyimide solution having a logarithmic viscosity of 0.9 dl / g.

Next, the solid content of the obtained polyimide solution was 7
5 parts by weight of o-cresol novolac type epoxy resin (Yukaka Shell Epoxy Co., Ltd., Epicoat 180)
H-65) (25 parts by weight) was blended and stirred for 2 hours at room temperature to prepare an adhesive resin solution. This resin solution was applied onto a glass plate and dried to form a film, which was used as a heat resistant adhesive film.

The glass transition point of this film and tensile rupture strength after curing by thermocompression bonding, tensile elastic modulus, linear expansion coefficient, dielectric constant, dielectric loss tangent, solder heat resistance, drill hole drilling property, through hole thermal shock reliability Each was measured. The physical properties are shown in Table 3.

Examples 2 to 7 Films having the compositions shown in Table 2 were prepared in the same manner as in Example 1, and the same properties as in Example 1 were measured. Its composition is shown in Table 2.
Table 3 shows the characteristics.

Comparative Examples 1 to 1 Films having the compositions shown in Table 2 were prepared in the same manner as in Example 1, and the same properties as in Example 1 were measured. Its composition is shown in Table 2.
Table 3 shows the characteristics.

[0050]

[Table 2]

[Table 3]

[0051]

EFFECTS OF THE INVENTION The heat-resistant adhesive film for a printed circuit board of the present invention has excellent heat resistance and chemical resistance inherent to polyimide.
It has a feature that it can be thermocompression-bonded at 250 ° C or lower at a lower temperature than conventional polyimide-based adhesives without impairing its electrical properties, and the cured film after thermocompression bonding has a low expansion coefficient and excellent dielectric properties. .

Therefore, the heat-resistant adhesive film for a printed circuit board according to the present invention can be suitably used as an adhesive for a multilayer printed circuit board, an adhesive for a composite circuit board, an adhesive for a coverlay film and the like.

[Table 2]

[Table 2]

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Watanabe 3-10-6 Hatazawa Minami, Kisarazu City, Chiba Prefecture (56) References JP-A-5-11276 (JP, A) JP-A-5-32960 (JP, A) JP-A-5-25453 (JP, A) JP-A-5-140526 (JP, A) JP-A-5-311144 (JP, A) JP-A-5-140525 (JP, A) JP-A-3 -205474 (JP, A) JP-A-5-331444 (JP, A) JP-A-5-1224 (JP, A) JP-A-2-168635 (JP, A) JP-A-6-200216 (JP, A) ) JP-A-6-322119 (JP, A) JP-A-6-329998 (JP, A) JP-A-5-112760 (JP, A) JP-A-5-32950 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C09J 4/00-201/10 C08G 73/00-73/10 H05K 3/00-3/46

Claims (2)

(57) [Claims] 1. A functional group having reactivity with an epoxy group is included.
Aromatic diamine and diamino containing aromatic diamine
React with siloxane and tetracarboxylic dianhydride
To obtain a polyimide resin (A) having a silicon unit
Epoxy to 70-99% by weight of this polyimide resin (A)
Resin (B) 1-30 wt% is compounded in the presence of a solvent
As a solution, apply this resin solution on the substrate and then dry
The glass transition point is characterized by peeling from the substrate.
60 ~ 170 ℃, the tensile strength of the cured film is 4
A to 20 kg / mm ^2, tensile elastic modulus is 100 to 300 / mm ²
A method for producing a single layer heat-resistant adhesive film for a polyimide-based printed circuit board . 2. A heat-resistant adhesive film for printed circuit board
The linear expansion coefficient after curing is (5 to 15) × 10 ^-5 / ° C, the dielectric constant is 3.5 or less at a frequency of 1 MHz, and the dielectric loss tangent is
0.005 der Ru請 Motomeko 1 producing a polyimide-based printed heat-resistant adhesive film substrate according below.