JPH0251167B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an element having an insulating film, and in particular, a protective coating (P-
The present invention relates to an element having an insulating film suitable for coating an N junction part or as an alignment film of a liquid crystal display element.

2. Description of the Related Art Semiconductor devices in which the surface of an element is protectively coated with a polyimide polymer have been known. However, aromatic polyimide polymers are generally insoluble in organic solvents, so when coating them,
After coating with a solution of polyamic acid, which is its precursor, the solvent is removed and a ring-closing reaction is caused by heating. Therefore, a high processing temperature is required, but
High-temperature treatment is undesirable not only from the viewpoint of workability but also because at high temperatures an undesirable Au--Al alloy is formed in the bonding portion, which tends to reduce the moisture resistance of the semiconductor device.

On the other hand, it is already known that aromatic polyimide-based materials can be used as alignment films in liquid crystal cells, particularly in nematic liquid crystal display devices that operate under the action of an electric field and utilize electrothermal optical effects. For example, 4, which is described in Japanese Patent Application Laid-open No. 51-65960,
The polyimide obtained by condensation of 4'-diaminodiphenyl ether and pyromellitic dianhydride has fairly good orientation uniformity and durability in deterioration tests. However, since such polyimide polymers are insoluble in organic solvents,
When forming an alignment film on a substrate, a solution of polyamic acid, which is a precursor of polyimide, is applied, and then, when the solvent is removed, dehydration and ring closure are performed. Therefore, it is necessary to set the processing temperature to 200℃,
This further promotes browning of the alignment film. As a result, the liquid crystal display element becomes brownish after being filled with liquid crystal.
At the same time, there were problems in that the visual field became dark and the contrast deteriorated, so that the function as a display element, especially the requirement for high quality display, was not met.

Furthermore, as demand for multilayer liquid crystal cells having a structure in which two or more liquid crystal layers are laminated via a transparent substrate has increased in recent years, coloring of conventional polyimide alignment films has become a problem.

An object of the present invention is to provide an element having an insulating film that can be formed by low-temperature processing.
Particularly for liquid crystal display elements, the purpose is to provide a liquid crystal display element having an alignment film that is not colored during film formation, has excellent transparency, and has an inconspicuous Nesa pattern.

In the present invention, the thickness of the semiconductor element coating film made of the aromatic polyetherimide polymer is preferably selected from the range of 1 to 300 μm. especially,
If the semiconductor device is a memory and a protective coating is applied to prevent soft errors caused by alpha rays,
Preferably, 100 μm is chosen.

The aromatic polyetheramide polymer used in the present invention is a polycondensation product of dinitrophthalimide of an aromatic diamine represented by the general formula () and an allurimetal diphenoxide represented by the general formula (). MO−Ar−OM () or by polycondensation of the bis(ether acid anhydride) of the general formula () and the aromatic diamine of the general formula (). H ₂ N-R-NH ₂ () (However, in the above formulas () to (), Ar and R are divalent aromatic residues,
M represents an alkali metal).

The present inventors have conducted repeated studies in order to obtain a polyimide that can be processed at relatively low temperatures and has less coloring, in order to reduce the coloring of liquid crystal display elements and improve transparency, which was a drawback of conventional polyimide films. . As a result, it was found that certain polyetherimides are soluble in polar solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. Using a solution of polyetherimide,
Since film formation requires only the removal of the solvent, processing can be performed at a relatively low temperature, and the alignment film is less likely to be colored.

The aromatic polyetherimide polymer used in the present invention has little coloring, is excellent in transparency, and can form an alignment film having sufficient liquid crystal alignment properties without conspicuous Nesa patterns. Furthermore, the alignment film of the present invention is also excellent for use in multilayer liquid crystal displays.

Specific examples of dihydric phenols used in the production of the aromatic polyetherimide used in the present invention include 2,2-bis(4-hydroxyphenyl)propane, 4,4'-dihydroxydiphenyl ether, and hydroquinone. , catechol, bis(4-hydroxyphenyl)methane, 4,4'-
Dihydroxydiphenyl sulfone, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenyl sulfide, 2,2-bis(4-hydroxyphenyl)-1,1,1,3,3, 3-hexafluoropropane, 2,5-dihydroxytoluene, 4,4'-dihydroxy-3,3'-dimethyldiphenyl, 3,3',5,5'-tetramethyl-
4,4'-dihydroxydiphenyl, bis[4-
Examples include (4-hydroxyphenoxy)phenyl]sulfone, bis[4-(4-hydroxyphenoxy)phenyl]ether, and 4,4'-di(P-hydroxyphenoxy)benzophenone.

Further, examples of aromatic diamines used in the production of aromatic polyetherimide used in the present invention include m-phenylene diamine, p-phenylene diamine, 4,4'-diaminodiphenylpropane, 4, 4′-diaminodiphenyl sulfide,
4,4'-diaminodiphenyl sulfone, 4,4'-
Diaminodiphenyl ether, 1,5-diaminonaphthalene, 2,4-diaminotoluene, 2,6
-Diaminotoluene, 4,4'-diaminodiphenylmethane, 4,4'-diaminobenzophenone, bis[4-(4-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)] phenyl]propane, 2,2-bis[4-
(4-aminophenoxy)phenyl]1,1,1,
3,3,3-hexafluoropropane, 4,4'-
Examples include (p-aminophenoxy)benzophenyl, bis[4-(4-aminophenoxy)phenyl]methane, bus[4-(4-aminophenoxy)phenyl]ether, and the like.

The aromatic polyetherimide polymer includes dimethylformamide, dimethylacetamide, N-
Dissolve in methylpyrrolidone, dimethyl sulfoxide, etc. to form a varnish. For semiconductor device coating, this can be applied to the device and formed into a film at a temperature of 100 to 200°C. Thereafter, it is sealed with, for example, epoxy resin, diallyl phthalate resin, phenol resin, unsaturated polyester resin, silicone resin, or the like.

In forming an alignment film for a liquid crystal display element, no special consideration is required when handling the polymer solution prepared as described above, and it can be carried out by brush coating, dipping, spin coating, printing, or other conventional methods. can.

The alignment film of the present invention can be formed directly on a substrate provided with a conductive layer, but an even more excellent liquid crystal display element can be obtained by using one in which an inorganic insulating film is provided below or above the conductive layer. be able to. Such inorganic insulating films include SiO ₂ ,
Films of Al ₂ O ₃ and TiO ₂ are suitable.

Further, in the present invention, in order to obtain an even stronger alignment film, one or more of epoxy-based and amino-based silane coupling agents can be used in combination.
Examples of the silane coupling agent include γ-aminopropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane. In application, it may be added dropwise into the above polymer solution, or an alignment film may be formed on top of the silane coupling agent film.

As an example of the liquid crystal sealed in the liquid crystal display element of the present invention, the following can be mentioned. These are usually applied as a mixture of two or more components.

(1) As a biphenyl type liquid crystal A mixture of (2) as an ester type liquid crystal, The mixture (3) of cyclohexane type liquid crystal is There is a mixture of

Next, the present invention will be explained by examples.

Example 1 52 parts by weight of 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 41 parts by weight of 2,2-bis[4-(4-aminophenoxy)] A mixture of phenyl]propane, 1000 parts by weight of N-methylpyrrolidone and 300 parts by weight of toluene was stirred at room temperature for about 1 hour and then refluxed at 150°C for about 1 hour. At this time, the water produced was distilled off azeotropically. Furthermore, 200 parts of toluene was added, and the temperature was raised to 180° C. while distilling off toluene, and then cooled. The aromatic polyetherimide polymer thus obtained was prepared into a 15% N-methylpyrrolidone solution. Apply this to MOS type LSI and
C. for 30 minutes, 150.degree. C. for 1 hour, and 200.degree. C. for 2 hours to form a film about 40 .mu.m thick on the surface of the device.

Thereafter, it was transfer molded and sealed with epoxy resin. 80℃, 90%RH, 1000 for this semiconductor device
The failure rate after hours was excellent at 0/90.

Example 2 Aromatic production as in Example 1 with 0.1 mol of 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride and 0.1 mol of metaphenylene diamino A group polyetherimide polymer was obtained. A varnish with a solid content of 15% was prepared in the same manner and applied to a MOS LSI. This semiconductor device
Moisture resistance at 80°C and 90% was good.

Example 3 From 43.6 parts of bis[4-(4-hydroxyphenoxy)phenyl]sulfone, 8 parts of an aqueous NaOH solution of sodium hydroxide in 50 parts of water, 30 parts of dimethyl sulfoxide and 100 parts of benzene. The mixture was heated with stirring, and water was removed by azeotroping with benzene. Then 45.8 parts of 1,3-di[4-nitrophthalimino]benzene and 300 parts of dimethyl sulfoside were added. 120℃
After reacting for 2 hours, the reaction mixture was poured into methanol to precipitate the polymer. After drying the obtained powder, it was dissolved in dimethylformamide and MOS
Apply to mold IC, 80℃, 30 minutes, 150℃, 1 hour,
After heating at 180°C for 2 hours, it was sealed with epoxy resin. This semiconductor device had good moisture resistance.

Example 4 52 parts by weight of 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 41 parts by weight of 2,2-bis[4-(4-aminophenoxy)] A mixture of phenyl]propane, 1000 parts by weight of N-methylpyrrolidone and 300 parts by weight of toluene was stirred at room temperature for about 1 hour and then refluxed at 150°C for about 1 hour. At this time, the water produced was distilled off azeotropically. Furthermore, 200 parts of toluene was added, and the temperature was raised to 180° C. while distilling off toluene, and then cooled. The aromatic polyetherimide polymer thus obtained was prepared into a 7% N-methylpyrrolidone solution. 50, 100, 150 nm using polymer solution using offset printing machine on liquid crystal cell substrate
An alignment film was printed, and the solvent was removed by heating at 180°C for 1 hour. Thereafter, a rubbing operation was performed in a certain direction with a cotton cloth, and an organic seal of epoxy resin was applied to the two substrates with a spacer interposed therebetween, thereby producing an element.
In this way, elements are formed, and these elements are
After separately injecting (1) biphenyl type liquid crystal, (2) ester type liquid crystal, and (3) cyclohexane type liquid crystal,
Each injection port was sealed with epoxy resin to create a liquid crystal display element. In either case, high-quality elements with very excellent transparency and inconspicuous Nesa patterns could be obtained.

Example 5 Produced in the same manner as in Example 1 with 0.1 mol of 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride and 0.1 mol of metaphenylene diamino. An aromatic polyetherimide polymer was obtained.

Add propyltriethoxysilane to this polymer solution.
0.1% by weight was added, an alignment film was formed in the same manner as in Example 1, and a liquid crystal display element was prepared using a glass frit seal, and its transparency and the presence or absence of a Nesa pattern were examined.

In both cases, high-quality elements with very excellent transparency and inconspicuous Nesa patterns could be obtained.

Example 6 From 43.6 parts of bis[4-(4-hydroxyphenoxy)phenyl]sulfone, 8 parts of an aqueous NaOH solution of sodium hydroxide in 50 parts of water, 30 parts of dimethyl sulfoxide and 100 parts of benzene. The mixture was heated with stirring, and water was removed by azeotroping with benzene. Next, 45.8 parts of 1,3-di[4-nitrophthalimino]benzene and 300 parts of dimethyl sulfoside were added. 120
After reacting for 2 hours at °C, the reaction mixture was poured into methanol to precipitate the polymer. After drying the obtained powder, it was dissolved in dimethylformamide and 5%
It was made into a solution. Using this _polymer solution, a 50 _{, 100} , A 150 nm alignment film was formed. In either case, high-quality elements with very excellent transparency and inconspicuous Nesa patterns could be obtained.

Claims (1)

[Claims] 1. The insulating film has the general formula () [However, Ar and R represent divalent aromatic residues. ] An element having an insulating film comprising an aromatic polyetherimide polymer having repeating units represented by the following. 2. Claim 1 provides that the aromatic polyetherimide polymer has the formula () (However, Ar in the formula is [formula] [formula] [formula] [formula] [formula] [formula] [formula] [formula] [formula] [formula] [formula] [formula] [formula] [formula] [formula] represents a group selected from the group consisting of, X is SO ₂ ,
An element having an insulating film, which is a polymer having a repeating unit represented by CO, [Formula] [Formula] O, or _CH2 . 3. Claim 1 provides that the aromatic polyetherimide polymer has the formula () [However, in the formula, R is metaphenylene, paraphenylene, [formula] [formula] [formula] and [formula] [formula] (however, Z is SO ₂ , CO, [formula] [formula] O, or CH ₂ An element having an insulating film _, characterized in that it is a polymer having a repeating unit selected from the group consisting of 4 Claims 1, 2, or 3
2. The element having an insulating film according to item 1, wherein the aromatic polyetherimide polymer layer has a thickness of 1 to 300 μm. 5. An element having an insulating film according to claim 1, 2, 3, or 4, wherein the insulating film coats a surface of a semiconductor element. 6. An element having an insulating film according to claim 5, wherein the semiconductor element is a memory, and the aromatic polyetherimide polymer layer has a thickness of 30 to 100 μm. 7. An element having an insulating film according to claim 1, 2, 3, or 4, wherein the insulating film is an alignment film of a liquid crystal display element.