JPH04304234A - Thermoplastic polyetherimide and electronic device using same - Google Patents

Abstract

PURPOSE:To cure at a relatively low temp., facilitate etching, and enable the use as an orientation film or overcoat film of a liq. crystal display device. CONSTITUTION:A thermoplastic polyetherimide is prepd. by polymerizing a tetracarboxylic acid component contg. 10-80mol% tetracarboxylic acid of formula I (wherein Y is a group of formula II, III, or IV; R1 is 5-18C alkyl; R2 is 1-18C alkyl; X is 1-4C alkyl; and a, b, c, and d are each 0-2) with a diamine component contg. 10-80mol% arom. diamine of formula V [wherein Y is -O-, -CO-, -CO2-, -SO2-, or a group of formula VI; R1 and R2 are each (perfluoro)alkyl; X is halogen or 1-4C alkyl; and a, b, c, and d are each 0-2] in a soln. at -20 to 200 deg.C.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a new thermoplastic polyetherimide and an electronic device using the same.

0002

[Prior Art] Conventionally, polyimide with excellent heat resistance obtained by polycondensing tetracarboxylic dianhydride and diamine has been used for wiring films, insulating films, buffer coat films, etc. of various electronic devices. .

In addition, as an alignment film for liquid crystal display elements, for example, polyimide of pyromellitic dianhydride and 4,4'-diaminodiphenyl ether condensation (Japanese Patent Publication No. 55-101
8), and recently, due to the requirements for transparency of display elements or high pretilt angles of liquid crystals, polyimides for this purpose have been proposed (Japanese Unexamined Patent Publication No. 63-259).
No. 515, Japanese Unexamined Patent Publication No. 64-25126). Furthermore, various polyimides have been similarly proposed for insulating films for multilayer wiring in semiconductor devices and the like (Japanese Patent Application Laid-open Nos. 50-8469 and 1982-6279).

0004

[Problem to be solved by the invention] Curing of polyimide film (
Imidization rate of 90% or higher) usually requires heating at a high temperature (250° C. or higher) for a long time (30 minutes or longer). Further, since polyimide after curing is generally infusible and insoluble, it is not easy to etch the film once formed using an alkaline solution or the like. However, in recent years, polyimide, which cures at low temperatures in a short time and is easily etched, is required for insulation of various electronic devices.

[0005] For example, in liquid crystal display devices, as liquid crystal elements have larger screens and higher density, the substrates of the elements have also become larger and more expensive because they are required to have higher precision. When a polyimide film has been used as a color filter or overcoat film for the substrate, it cannot be easily peeled off even if a defect occurs in the film, so it is important to be able to easily reuse (repair) the substrate. This is becoming an issue. In addition, as wiring becomes finer in the field of semiconductor devices, stress migration of wiring due to high temperature curing of polyimide used as an insulating layer (cracks, disconnections, etc. due to thermal stress caused by differences in thermal expansion coefficients of materials) The occurrence of this is a problem.

An object of the present invention is to provide a new thermoplastic polyetherimide that can be cured at relatively low temperatures (250° C. or lower) and is relatively easy to etch.

Another object of the present invention is to provide an electronic device using the polyetherimide composite.

[0008]

[Means for Solving the Problems] As a result of intensive studies to solve the above problems, the present inventors have found that a specific alkyl The present invention was accomplished by discovering that the problem could be solved by introducing a flexible chain. The gist of the present invention is as follows.

(1) General formula [1]

0010

[Chemical formula 3]

[0011] where R1 is an alkyl group having 5 to 18 carbon atoms, R2 is an alkyl group having 1 to 18 carbon atoms, X is an alkyl group having 1 to 4 carbon atoms, and a, b, c and d are 0, 1 or 2. It is. ) A thermoplastic polyetherimide characterized by being a polymer of a composition of tetracarboxylic acid and diamine represented by:

(2) Furthermore, the diamine has the general formula [
2]

[0013]

[C4]

##STR1## where R1 and R2 represent an alkyl group or a perfluoroalkyl group. In addition, X is a halogen atom or an alkyl group having 1 to 4 carbon atoms, and a, b, c and d are 0,
A thermoplastic polyetherimide characterized by being a diamine represented by (1 or 2).

(3) The tetracarboxylic acid represented by the general formula [1] is contained in other tetracarboxylic acids at a molar ratio of 1
It is characterized by containing 0 to 80. In addition, the general formula [2
] is characterized in that the aromatic diamine represented by the formula is contained in other diamines in a molar ratio of 10 to 80.

The above polymer can be used in various electronic devices, such as
By using it in the alignment film of a liquid crystal display device, it becomes possible to use it in conjunction with a color filter or overcoat with low heat resistance, and also in terms of characteristics, brightness unevenness is improved. In addition, recycling and etching of the substrate becomes significantly easier. Furthermore, even when used as an insulating film of a semiconductor device, the curing temperature is low, so the thermal stress applied to the aluminum wiring layer is small, so stress migration and the like can be suppressed.

When used as an alignment film for a liquid crystal display device, it is important that R1 of the tetracarboxylic acid represented by the general formula [1] has 5 or more carbon atoms in order to increase the pretilt angle of the liquid crystal molecules. It is.

The bis[4-(dicarboxyphenoxy)phenyl] type tetracarboxylic acid represented by the above formula [1] is 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]. Octane, 2,2-bis[4
-(3,4-dicarboxyphenoxy)phenyl]decane, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]tridecane, 2,2-bis[4-(3
,4-dicarboxyphenoxy)phenyl]dodecane,
2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]heptane, 1,1-bis[4-(3,4-
dicarboxyphenoxy)phenyl]-2-methyloctane, 1,1-bis[4-(3,4-dicarboxyphenoxy)phenyl]-2-methyldodecane, 1,1-bis[4-(3,4- dicarboxyphenoxy)phenyl]-2-ethylpentadecane, 2,2-bis[3,5-
Dimethyl-4-(3,4-dicarboxyphenoxy)phenyl]dodecane, 2,2-bis[3,5-dimethyl-
4-(3,4-dicarboxyphenoxy)phenyl]octane, 2,2-bis[3,5-dimethyl-4-(3,
4-dicarboxyphenoxy)phenyl]decane, 2,
2-bis[3,5-diethyl-4-(3,4-dicarboxyphenoxy)phenyl]tridecane, 1,1-bis[4-(3,4-dicarboxyphenoxy)phenyl]
There are dianhydrides or carboxylic acids such as cyclohexane,
These are preferably used in a composition having a molar ratio of 10 to 80; if the molar ratio exceeds 80, there is a problem that the degree of polymerization is difficult to increase.

Examples of the tetracarboxylic acids other than the bis[4-(dicarboxyphenoxy)phenyl] type include pyromellitic acid, methylpyromellitic acid, dimethylpyromellitic acid, di(trifluoromethyl)pyromellitic acid,
,3',4,4'-biphenyltetracarboxylic acid, 5,
5'-dimethyl-3,3',4,4'-biphenyltetracarboxylic acid, p-(3,4-dicarboxyphenyl)
Benzene, 2,3,3',4'-tetracarboxydiphenyl, 3,3',4,4'-tetracarboxydiphenyl ether, 2,3,3',4'-tetracarboxydiphenyl ether, 3,3',4 , 4'-tetracarboxybenzophenone, 2,3,3',4'-tetracarboxybenzophenone, 2,3,6,7-tetracarboxynaphthalene, 1,4,5,7-tetracarboxynaphthalene, 1,2, 5,6-tetracarboxynaphthalene, 3,3',4,4'-tetracarboxydiphenylmethane, 2,3,3',4'-tetracarboxydiphenylmethane, 2,2-bis(3,4-dicarboxyphenyl) Propane, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane, 3,3',4,4
'-Tetracarboxydiphenyl sulfone, 3,4,9
, 10-tetracarboxyperylene, butanetetracarboxylic acid, 3,3',4,4'-ethylene glycol bis(phenyl)tetracarboxylic acid, cyclobutanetetracarboxylic acid, cyclopentanetetracarboxylic acid, and other dianhydrides or carboxylic acids. etc.

On the other hand, specific examples of the diamine represented by the general formula [2] include 2,2-bis[4-(p-aminophenoxy)phenyl]ether, 2,2-bis[4-
(p-aminophenoxy)phenyl]ketone, 2,2-
Bis[4-(p-aminophenoxy)phenyl]ester, 2,2-bis[4-(p-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(m-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(p
-aminophenoxy)]biphenyl, 2,2-bis[4
-(p-aminophenoxy)phenyl]propane, 2,
2-bis[4-(p-aminophenoxy)phenyl]pentane, 2,2-bis[4-(p-aminophenoxy)
Phenyl]octane, 1,1,1,3,3,3-hexafluoro-2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,1,1,3,3,3-hexa Fluoro-2,2-bis[3,5-dimethyl-4-(
4-aminophenoxy)phenyl]propane, 1,1,
1,3,3,3-hexafluoro-2,2-bis[3,
5-dibromo-4(4-aminophenoxy)phenyl]
Propane, 1,1,1,2,2,4,4,5,5,5-
decafluoro-3,3-bis[4-(4-aminophenoxy)phenyl]pentane, 1,1,1,3,3,4,
Examples include 4,4-octafluoro-2,2-bis(4-aminophenyl)butane.

Specific examples of diamines other than those mentioned above include p-phenylenediamine, m-phenylenediamine, diaminodiphenyl ether, diaminodiphenylmethane, 2,2-diaminodiphenylpropane, diaminodiphenylsulfone, diaminobenzophenone, diaminonaphthalene, and diaminota. -phenyl, 1,4-bis(
Aromatic diamines such as 4-aminophenoxy)benzene, alicyclic diamines such as diamino dicyclohexyl ether and diaminocyclohexane, aliphatic diamines such as 1,6-diaminohexane and 1,8-diaminooctane, diaminosiloxane, diaminosilane, etc. There is.

[0022] The method for synthesizing the precursor varnish in the present invention is as follows:
Generally, solutions such as N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, dimethyl sulfate, sulfolane, butyllactone, cresol, phenol, halogenated phenol, cyclohexanone, dioxane, tetrahydrofuran, acetophenone, etc. It is carried out in the range of -20 to 200°C.

[0023] In the present invention, the precursor varnish is
In addition to a complete amic acid or a derivative thereof, it may be one in which imidization has proceeded to some extent. In addition, when adhesiveness is required, silane coupling agents, titanate coupling agents, aluminum alcoholates, etc. can be used to roughen the adhesive surface.
Surface treating agents such as aluminum chelate, zirconium chelate, and aluminum acetylacetone are used, and these surface treating agents can be added to the precursor varnish.

In order to adjust the fluidity, coefficient of thermal expansion, modulus of elasticity, dielectric constant, refractive index, etc. of the precursor varnish, inorganic or organic powders, fibers, chopped strands, etc. may be used to defeat the purpose of the present invention. They may be mixed and used within a certain range.

[0025] Formation of the polyetherimide precursor film is as follows:
This can be done by general spin coating, printing, or the like.

Furthermore, the tetracarboxylic acid represented by the general formula [1] can be applied to various fields such as curing agents and plasticizers for ordinary epoxy resins, polyamide resins, polyester resins, and photosensitive resins.

[0027]

[Action] The thermoplastic polyetherimide of the present invention has a more flexible conformation than conventional polyimides because both the tetracarboxylic acid and the diamine have a bis[(diphenoxy)phenyl] type basic skeleton. . By introducing a long-chain alkyl group in the direction of the short axis of the molecule of the central bonding group Y of the tetracarboxylic acid, the flexible properties of the polymer are further enhanced.
It is thought that the glass transition temperature was also lowered, making low-temperature curability and etching easier.

[0028]

[Examples] The present invention will be specifically explained below with reference to Examples.

[Example 1] Synthesized 2,2-bis[
0.5 mol% of 4-(3,4-dicarboxyphenoxy)phenyl]octane dianhydride, 3,3',4,4'-
0.5 mol% of biphenyltetracarboxylic dianhydride, 0.7 mol% of 2,2-bis[4-(p-aminophenoxy)phenyl]propane, and 0.3 mol% of diaminodiphenyl ether in N-methyl A polyetherimide precursor varnish was prepared by reacting in -2-pyrrolidone at 5°C for 10 hours. Reduced viscosity ηs of the obtained precursor varnish
p/c is 0.3 dl/g (0.5% by weight, NMP solution,
30°C).

[0030] Note that the above-mentioned 2,2-bis[4-(3,4
The IR spectrum of -dicarboxyphenoxy)phenyl]octane dianhydride is shown in FIG. 2930cm￣1,
Absorption based on alkyl group at 2850 cm￣1,
Absorption based on carbonyl groups is seen at 1780cm￣1 and 1850cm￣1.

After diluting the polyetherimide precursor varnish to a concentration of 5% by weight, SiO2-T is deposited on the transparent electrode of the substrate.
Spin coat on the surface on which the iO2 inorganic film is formed, and
C. for 5 minutes to form a polyetherimide film of 800 Å. In order to make the twist angle of the liquid crystal molecules sandwiched by the substrates 260 degrees, the above-mentioned upper and lower substrates were rubbed at different angles, and a spacer was sandwiched between the substrates to assemble a liquid crystal cell with a gap of 6 μm. The cell contains a nematic liquid crystal whose main components are biphenyl liquid crystal, phenylcyclohexane liquid crystal, ester cyclohexane liquid crystal, and phenylcyclohexane methyl ether liquid crystal, to which 0.5% by weight of an optically active substance (manufactured by Merck & Co., Ltd.: S811) is added. The material was vacuum sealed.

Frequency change of threshold voltage of the liquid crystal cell (
30Hz/500Hz) showed a value of 0.99, indicating that brightness unevenness was reduced. Further, a substrate with a defective polyetherimide film was etched in an alkaline solution for 5 minutes to remove the polyetherimide film, and the substrate was recycled.

[Example 2] Synthesized 2,2-bis[
4-(3,4-dicarboxyphenoxy)phenyl]tridecane dianhydride 0.3 mol%, pyromellitic dianhydride 0.7 mol% and 1,6-diaminohexane 0
．． 7 mol%, 0.3 mol% of 1,1,1,3,3,3-hexafluoro-2,2-bis[4-(4-aminophenoxy)phenyl]propane in dimethylacetamide at 20°C. The mixture was reacted for 15 hours to produce a polyetherimide precursor varnish. Reduced viscosity η of the obtained precursor varnish
sp/c was 0.4 dl/g (0.5% by weight, NMP solution, 30°C).

[0034] Note that the above-mentioned 2,2-bis[4-(3,4
The IR spectrum of -dicarboxyphenoxy)phenyl]tridecane dianhydride is shown in FIG. 2930cm￣1
, 2850 cm 1, and an absorption based on a carbonyl group at 1780 cm 1, 1850 cm 1.

After diluting the polyetherimide precursor varnish to a concentration of 3% by weight, the solution was spin-coated on the indium oxide transparent electrode 4 of the color liquid crystal display device shown in FIG. 3, and heat-treated at 200° C. for 10 minutes. A polyetherimide film 5 having a thickness of 500 Å was formed. Thereafter, in order to make the twist angle of the liquid crystal molecules 280 degrees, the upper and lower substrates 1 were rubbed at different angles, and a spacer was inserted between the substrates to assemble a liquid crystal cell with a gap of 5 μm. The same liquid crystal material as in Example 1 was vacuum-sealed into the cell.

Even if a dye color filter with low heat resistance is used, since the baking temperature of the varnish is relatively low at 180° C., the filter will not deteriorate or discolor, and the cell characteristics will also be affected by the frequency change of the threshold voltage ( 30Hz/500Hz)
showed a value of 0.99, and it was possible to reduce uneven brightness. In addition, substrates with defective polyetherimide films were removed by etching in alkali. Note that immersion for about 5 minutes is sufficient to remove the defective polyetherimide film.

[Example 3] Synthesized 2,2-bis[
0.7 mol% of 4-(3,4-dicarboxyphenoxy)phenyl]heptane dianhydride, 2,2-bis(3,4
-dicarboxyphenyl)hexafluoropropane dianhydride and 1,1,1,3,3,3-hexafluoro-2,2-bis[4-(4-aminophenoxy)phenyl]propane. 0.7 mol% of diaminosiloxane and 0.3 mol% of diaminosiloxane in dimethylacetamide.
C. for 12 hours to prepare a polyetherimide precursor varnish. Reduced viscosity ηsp/ of the obtained precursor varnish
c is 0.3 dl/g (0.5% by weight, NMP solution, 30
℃).

[0038] Note that the above-mentioned 2,2-bis[4-(3,4
The IR spectrum of -dicarboxyphenoxy)phenyl]heptane dianhydride is shown in FIG. 2930cm￣1,
Absorption based on alkyl group at 2850 cm￣1,
Absorption based on carbonyl groups is seen at 1780cm￣1 and 1850cm￣1.

The polyetherimide precursor varnish was diluted to a concentration of 3% by weight, spin-coated as an overcoat for a color filter, and heat-treated at 210° C. for 10 minutes. Further, the solution was further spin-coated onto the transparent electrode, and heat-treated in the same manner to form a polyetherimide film.

In order to make the twist angle of the liquid crystal molecules 240 degrees, the upper and lower substrates were rubbed at different angles, and a spacer was inserted between the substrates to assemble a liquid crystal cell with a gap of 5.5 μm. The same liquid crystal material as in Example 1 was vacuum-sealed into the cell.

[0041] Excellent flatness as an overcoat film for the color filter, no deterioration or discoloration of the color filter, and cell characteristics with a change in threshold voltage frequency (30Hz/30Hz/
500Hz) showed a value of 0.99, and it was possible to reduce uneven brightness. Note that a substrate with a defective polyetherimide film could be removed and regenerated by etching in an alkali for about 5 minutes.

[Example 4] Synthesized 1,1-bis[
4-(3,4-dicarboxyphenoxy)phenyl]-
0.7 mol% 2-methylheptane dianhydride, 0.3 mol% cyclobutanetetracarboxylic acid, and 0 mol% 2,2bis[4-(p-aminophenoxy)phenyl]ketone.
．． 3 mol%, 1,8-diaminooctane 0.7 mol%
were reacted in N-methyl-2-pyrrolidone at 120°C for 6 hours to prepare a polyetherimide precursor varnish. The reduced viscosity η sp/c of the obtained precursor varnish is 0.25 d
l/g (0.5% by weight, NMP solution, 30°C).

[0043] Note that the above-mentioned 2,2-bis[4-(3,4
FIG. 5 shows the IR spectrum of -dicarboxyphenoxy)phenyl]-2-methylheptane dianhydride. 293
An absorption based on an alkyl group is observed at 0cm￣1,2850cm￣1, and an absorption based on a carbonyl group is observed at 1780cm￣1,1850cm￣1.

[0044] After diluting the polyetherimide precursor varnish to a concentration of 5% by weight, the solution was spin-coated on the active matrix electrode and the color filter.
A polyetherimide film having a thickness of 1200 Å was formed by heat treatment at 20° C. for 5 minutes. After that, the twist angle of the liquid crystal molecules was adjusted to 9
A liquid crystal cell with a gap of 5 .mu.m was assembled by rubbing the substrate to 0 degrees and inserting a spacer between the substrates. The same liquid crystal material as in Example 1 was vacuum-sealed into the cell.

Even if a color filter with low heat resistance is used, the varnish will not deteriorate or fade due to baking, and
Substrates with defective polyetherimide films were removed by etching in alkali. Note that immersion for about 5 minutes is sufficient to remove the defective polyetherimide film.

[Example 5] Synthesized 1,1-bis[
0.5 mol% of 4-(3,4-dicarboxyphenoxy)phenyl]cyclohexane dianhydride, 0.5 mol% of pyromellitic dianhydride and 2,2-bis[4-(p
-aminophenoxy) phenyl octane 0.7 mol%
, 0.3 mol% of diaminosiloxane was dissolved in dimethylacetamide and dimethylformamide at -10°C, 1
The mixture was reacted for 5 hours to produce a polyetherimide precursor varnish. The reduced viscosity ηsp/c of the obtained precursor varnish is 0
．． 45dl/g (0.5% by weight, NMP solution, 30°C)
Met.

[0047] Note that the above-mentioned 1,1-bis[4-(3,4
The IR spectrum of -dicarboxyphenoxy)phenyl]cyclohexane dianhydride is shown in FIG. 2930cm
Absorption based on alkyl group at ￣1,2850cm￣1,
In addition, absorptions based on carbonyl groups are seen at 1780cm￣1 and 1850cm￣1.

After diluting the polyetherimide precursor varnish to a concentration of 7% by weight, the solution was coated with an offset printing machine on the SiO2 inorganic film formed on the transparent electrode, and
C. for 5 minutes to form a 1000 Å polyetherimide film. After that, the twist angle of the liquid crystal molecules was set to 240
In order to make the upper and lower substrates at different angles, the upper and lower substrates were labiled at different angles, and a spacer was placed between the substrates to create a gap of 5.5 μm.
Assembled a liquid crystal cell of m. The same liquid crystal material as in Example 1 was vacuum-sealed into the cell.

Frequency change of threshold voltage (30Hz/5
00Hz) was 0.99, and it was possible to reduce unevenness in brightness. Furthermore, a phase plate was added to create a black and white liquid crystal display device. Note that immersion for about 5 minutes is sufficient to remove the defective polyetherimide film.

[Embodiment 6] Each of the above embodiments has been described with reference to the case where the present invention is applied to a liquid crystal display device, but specific examples of the case where the present invention is applied to various electronic devices will be explained with reference to the drawings.

FIG. 7 is a schematic cross-sectional view of an LSI having a multilayer wiring structure. An SiO2 insulating film 8 is provided on the surface of the semiconductor element 7 to form a metal film, and unnecessary portions of the metal film are removed by etching to provide first wiring 9 having a desired wiring pattern. The wiring 9 is electrically connected to the semiconductor element 7 through a through hole provided at a predetermined location in the SiO2 film 8. Next, the polyetherimide precursor varnish used in Example 1 was spin coated, and the final temperature was 2.
After forming the polyetherimide film 10 at 20° C., a circuit was formed by electrically connecting the second wiring 9' made of a metal film and the first wiring 9 to obtain an LSI. Also,
A protective layer of epoxy resin 11 was provided on the surface of the LSI.

The above LSI has a polyetherimide film 10
Since the curing temperature is as low as 220° C., the thermal stress applied to the metal (aluminum) wiring layer is small, so stress migration is less likely to occur.

FIG. 8 is a schematic cross-sectional view of a semiconductor memory element having an α-ray shielding layer. A memory element 13 made of a silicon chip is fixed on the substrate 12, and the memory element 13 is electrically connected to the outside by a bonding wire 14. The polyetherimide precursor varnish of Example 2 is spin-coated on the surface of the memory element 13, and
It was cured at 20° C. to form an α-ray shielding layer film 15. No occurrence of stress migration was observed.

FIG. 9 is a schematic cross-sectional view of a thin film magnetic head. A lower alumina 17, a lower magnetic material 18, and a gap alumina 19 are formed on a substrate 16, and a conductor coil 20 is spin-coated with the polyetherimide precursor varnish of Example 3 and cured at 220° C. to form an interlayer. Insulating film 2
Insulated with 1. A magnetic material 18' was provided on top of this. There was no deterioration of the conductor coil 20 due to the hardening of the polyetherimide, and a thin film magnetic head having an interlayer insulating film 21 with excellent flatness was obtained.

FIG. 10 is a schematic cross-sectional view of a magnetic bubble memory element. A conductor 25 is provided on a garnet substrate 22, and the polyetherimide precursor varnish of Example 4 is spin-coated thereon and cured at 200°C to form a polyetherimide insulating film 23.
After forming No. 4, patterning was performed using a conventional method. Deterioration of the conductor 25 was prevented, and no stress migration of the magnetic valve memory element was observed.

FIG. 11 is a schematic cross-sectional view of a high-density wiring board. A thermally oxidized SiO2 film 27 is formed on a silicon wafer substrate 26, and a first copper wiring 29 is formed on the film. Then, the second copper wiring 29 is connected via the insulating film 28.
is formed, and an insulating film 28 is further formed thereon. Pb/Sn electrode 31 via Cr/Ni/Au film 30
is provided. As the insulating film 28, the above-mentioned Example 5
After spin-coating the polyetherimide precursor varnish,
A patterned film was formed from polyetherimide cured at 200°C. In the copper wiring of the high-density wiring board of this example, dissolution of copper by carboxylic acid was suppressed, and no deterioration of the film was observed.

FIG. 12 is a schematic cross-sectional view of the flexible printed circuit board. The polyetherimide precursor varnish of Example 1 is applied directly to the copper foil and cured at low temperature to form the insulating film 33 of the polyetherimide film, and then the copper foil is etched into a predetermined pattern to form the wiring layer 32. Then, a flexible printed circuit board was created. Since the insulating film 33 was formed at 200° C., oxidation deterioration of the copper foil was suppressed, and a flexible printed circuit board with high adhesive strength to the copper foil was obtained.

FIG. 13 is a schematic cross-sectional view of an LSI-mounted printed wiring board. An LSI 39 is embedded in a metal substrate 34 using a film carrier method, and the LSI is connected to a copper wiring 35 through solder bumps and solder balls 36. It is insulated from the carrier film 37 by an interlayer insulating film 40 except for the conductive portion. The terminal 38 is connected to the outside. The polyetherimide precursor varnish of Example 2 was formed on the interlayer insulating film 40 by spin coating and cured at 200°C. No deterioration of the polyetherimide film due to copper was observed.

[Comparative Example 1] 1.0 mol % of 3,3',4,4'-biphenyltetracarboxylic dianhydride and 1.0 mol% of 2,2-bis[4-(p-aminophenoxy)phenyl]pentane. 0 mol% was reacted in N-methyl-2-pyrrolidone at 5°C for 5 hours to prepare a polyimide precursor varnish. The reduced viscosity ηsp/c of the obtained precursor varnish was 0.5 dl/g (0.5% by weight, NMP solution, 30°C)
Met.

After diluting the above precursor varnish to 4% by weight, it was spin-coated on the indium oxide transparent electrode of the color liquid crystal display device shown in FIG. 3, and heat-treated at 250° C. for 30 minutes.
A polyimide film with a thickness of 0 Å was formed. In order to make the twist angle of the liquid crystal molecules 260 degrees, the upper and lower substrates are rubbed at different angles, and a spacer is placed between the substrates to create a gap of 5.
A μm liquid crystal cell was assembled. The above-mentioned Example 1 was applied to the liquid crystal cell.
The same liquid crystal material was vacuum sealed. The attached color filter deteriorated and discolored, and the frequency change (30 Hz/500 Hz) of the threshold voltage of the liquid crystal cell was 0.95. In the cell, uneven brightness was observed. Further, when a substrate with a defective polyimide film was etched in an alkali, it took more than 30 minutes for the film to peel off.

[0061] When the above was cured at 220°C for 5 minutes, there was no deterioration or fading of the color filter, but the imidization rate was less than 50%, and more uneven brightness occurred than when curing at 250°C. .

[Comparative Example 2] 1.0 mol% of cyclobutanetetracarboxylic dianhydride and 1,1,1,3,
A polyimide precursor varnish was prepared in the same manner as in Comparative Example 1 except that 1.0 mol % of 3,3-hexafluoro-2,2-bis[4-(4-aminophenoxy)phenyl]propane was added. Using this, a liquid crystal cell was created in the same manner as in Comparative Example 1. The attached color filter deteriorated and faded, causing uneven brightness of the liquid crystal cell. Further, when a substrate with a defective polyimide film was etched in an alkali, it took more than 30 minutes for the film to peel off.

[0063] When the above was cured at 220°C for 5 minutes, there was no deterioration or fading of the color filter, but the imidization rate was less than 50%, and more uneven brightness occurred than when curing at 250°C. .

[Comparative Example 3] The polyimide precursor varnish used in Comparative Example 1 was applied as the interlayer insulating film 10 of the semiconductor element 7 of the LSI shown in FIG. 7 and cured at 250°C. Also,
25 applied to the α-ray shielding layer 15 of the semiconductor memory device in FIG.
Cured at 0°C.

Since these had a high curing temperature of 250° C., the thermal stress applied to the aluminum wiring layer increased, causing stress migration.

[Comparative Example 4] The polyimide precursor varnish used in Comparative Example 2 was applied to the interlayer insulating film 21 of the thin film magnetic head shown in FIG. 9 and the insulating film 2 of the magnetic bubble memory element shown in FIG.
3. Applied to the insulating film 33 of a flexible printed circuit board,
It was cured at 250°C. As a result, the conductor coil, permalloy, copper plate, etc. deteriorated.

[0067]

Effects of the Invention The polyimide of the present invention can be cured in a short period of time at a temperature of 220° C. or lower to achieve an imidization rate of 90% or higher. Furthermore, since the polyimide film can be easily etched, unnecessary films can be easily removed. Therefore, it becomes easy to recycle a substrate with a defective film, and the yield of products can be improved.

Furthermore, when used in insulating films, buffer coat films, etc. of various electronic devices, it is possible to suppress the occurrence of stress migration, etc., thereby making it possible to provide electronic devices with excellent quality.

In particular, as an alignment film for a liquid crystal display device, unevenness in brightness is less likely to occur, and deterioration and discoloration of the color filter film provided can be prevented.

[Brief explanation of drawings]

FIG. 1 is an infrared absorption spectrum of 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]octane dianhydride.

FIG. 2 is an infrared absorption spectrum of 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]tridecane dianhydride.

FIG. 3 is a schematic cross-sectional view of a color liquid crystal display device.

FIG. 4 is an infrared absorption spectrum of 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]heptane dianhydride.

FIG. 5 is an infrared absorption spectrum of 1,1-bis[4-(3,4-dicarboxyphenoxy)phenyl]-2-methylheptane dianhydride.

FIG. 6 is an infrared absorption spectrum of 1,1-bis[4-(3,4-dicarboxyphenoxy)phenyl]cyclohexane dianhydride.

FIG. 7 is a schematic cross-sectional view of an LSI having a multilayer wiring structure.

FIG. 8 is a schematic cross-sectional view of a semiconductor memory element having an α-ray shielding layer.

FIG. 9 is a schematic cross-sectional view of a thin film magnetic head.

FIG. 10 is a schematic cross-sectional view of a magnetic bubble memory element.

FIG. 11 is a schematic cross-sectional view of a high-density wiring board.

FIG. 12 is a schematic cross-sectional view of a flexible printed circuit board.

FIG. 13 is a schematic cross-sectional view of an LSI-mounted printed wiring board.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Glass substrate, 2... Color filter, 3... Overcoat film, 4... Electrode, 5... Alignment film, 6... Liquid crystal layer, 7,34
... Substrate, 8... SiO2 film, 9, 32... Wiring layer, 10... Polyetherimide film, 11... Epoxy resin, 12, 16
, 22, 26... Substrate, 13... Memory element, 14... Bonding wire, 15... α-ray shielding layer, 17... Lower alumina, 18... Magnetic material, 19... Gap alumina, 20... Conductor coil, 21, 33, 40... Insulating film, 22...substrate, 23
, 28... Insulating film, 24... Permalloy, 25... Conductor, 27... SiO2 film, 29, 35... Copper wiring, 30... Cr
/Ni/Au film, 31...Pb/Sn electrode, 36...solder ball, 37...carrier film, 38...terminal, 39...L
S.I.

Claims (15)

[Claims] [Claim 1] General formula [1] [Formula 1], R1 has 5 to 18 carbon atoms, and R2 has 1 to 18 carbon atoms.
an alkyl group, X is an alkyl group having 1 to 4 carbon atoms, a,
b, c and d are 0, 1 or 2. ) A thermoplastic polyetherimide characterized by being a polymer of a composition of tetracarboxylic acid and diamine represented by: 2. The thermoplastic polyetherimide according to claim 1, wherein the tetracarboxylic acid represented by the general formula [1] is contained in the other tetracarboxylic acid in a molar ratio of 10 to 80. 3. The diamine has the general formula [2] [Chemical formula 2], and R1 and R2 each represent an alkyl group or a perfluoroalkyl group. Further, the thermoplastic polyamide is an aromatic diamine represented by X is a halogen atom, an alkyl group having 1 to 4 carbon atoms, and a, b, c and d are 0, 1 or 2. ether imide. 4. The thermoplastic polyetherimide according to claim 3, wherein the aromatic diamine represented by the general formula [2] is contained in the other diamine in a molar ratio of 10 to 80. 5. A liquid crystal display device in which a nematic liquid crystal exhibiting positive dielectric anisotropy is sandwiched between a pair of substrates having transparent electrodes and at least one of which is transparent, wherein A liquid crystal display device characterized in that an alignment film of plastic polyetherimide is provided between a substrate and a liquid crystal layer. 6. A nematic liquid crystal exhibiting positive dielectric anisotropy and to which an optically active substance is added is sandwiched between a pair of substrates having transparent electrodes and at least one of which is transparent, and the twist angle of the liquid crystal is 240. A super-twist liquid crystal display device having a temperature of at least 100%, characterized in that an alignment film of thermoplastic polyetherimide represented by the general formula [1] is provided between the substrate and the liquid crystal layer. Display device. 7. A nematic liquid crystal exhibiting positive dielectric anisotropy and to which an optically active substance is added is sandwiched between a pair of substrates having transparent electrodes and at least one of which is transparent, and the twist angle of the liquid crystal is 240. In a color liquid crystal display device that is
1. A color liquid crystal display device, wherein an overcoat film between a transparent electrode and a color filter is made of thermoplastic polyetherimide represented by the general formula [1]. 8. The liquid crystal display device according to claim 5, wherein the electrode is an active matrix type electrode. 9. A semiconductor device, wherein the surface of the semiconductor element and the insulating film of the multilayer wiring formed on the surface are made of thermoplastic polyetherimide represented by the general formula [1]. 10. A semiconductor device, wherein the α-ray shielding layer provided on the surface of the semiconductor element is a thermoplastic polyetherimide represented by the general formula [1]. 11. A thin film magnetic head comprising: a lower magnetic layer provided on an insulating substrate; a conductor layer insulated from the lower magnetic layer by an insulating layer; and an upper magnetic layer provided on the insulating layer. 1. A thin film magnetic head, wherein the insulating layer is made of thermoplastic polyetherimide represented by the general formula [1]. 12. A semiconductor device comprising wiring connecting a semiconductor element mounted on a substrate to a circuit of a carrier film, and an interlayer insulating layer insulating the wiring, wherein the insulating layer has a heat resistance represented by the general formula [1]. A semiconductor device characterized by being made of plastic polyetherimide. 13. A magnetic bubble memory element comprising a conductor pattern provided on a magnetic substrate, and an insulating layer for insulating between the conductor pattern and the upper magnetic pattern, wherein the insulating layer is represented by the general formula [1]. A magnetic bubble memory device characterized by being made of thermoplastic polyetherimide. 14. A high-density multilayer wiring board in which multilayer wiring is formed on a ceramic substrate via a thin film insulating layer, wherein the thin film insulating layer is made of thermoplastic polyetherimide represented by the general formula [1]. A high-density multilayer wiring board characterized by: 15. A flexible printed board device comprising a substrate and metal wiring, wherein the substrate is made of thermoplastic polyetherimide represented by the general formula [1].