JPS59212834A - Photosensitive heat resistant material - Google Patents

Abstract

PURPOSE:To obtain a microworkable and heat resistant material by reacting an unsatd. deriv. with amino groups produced by additionally reacting an unsatd. aziridine compd. with carboxylic groups of a polyamide acid and mixing the product with a bisazide compd. CONSTITUTION:An aziridine compd. having an unsatd. group represented by general formula ( I ) (R3 is a group having an unsatd. bond) is reacted with carboxylic acid groups linked to the side chains of a polyamide acid obtained by reacting diamine with tetracarboxylic dianhydride to produce a new amino group. An unsatd. deriv. represented by the general formula: R4-COX (R4 is a group having an unsatd. bond, and X is -OH, glycidyl, or isocyanate) is reacted with this resultant amine to obtain a polyimide precursor having an unsatd. bond. A substrate is coated with a mixture of said precursor and a bisazide compd. as a photo-crosslinking agent, imagewise exposed and developed to obtain a relief, and further it is heat-treated at 200-400 deg.C.

Description

[Detailed description of the invention] The present invention relates to a novel photosensitive heat-resistant material.

Conventionally, inorganic materials such as silicon oxide have been widely used in the semiconductor industry as insulating layers and passivation layers of solid-state devices.

On the other hand, organic materials have properties such as low stress, excellent smoothness, and high purity compared to inorganic materials, and in recent years, technology for using them as insulating layers and passivation layers has been developed, and some semiconductors It has been put into practical use in devices.

When an organic material is used for the above-mentioned purpose, the material is required to have thermal stability because it undergoes work steps such as die bonding, and it is necessary to use a heat-resistant organic material. Therefore, usually
Polyimide, which has excellent heat resistance, is being widely studied.

When polyimide is used as an insulating layer or passivation layer of a solid-state device, photoresist is generally used in the process of microfabrication, such as conductive parts between upper and lower conductor layers and through-holes for connection to external lead wires. Chemical etching treatment is performed.

For example, polyamic acid, which is a polyimide precursor, is coated on a substrate, heat treated to convert it to polyimide, a photoresist relief pattern is formed on the polyimide film, and the polyimide film is selectively chemically etched using a hydrazine-based etching agent. A relief pattern is formed on the polyimide.

However, in the patterning of polyimide in the above process,
Processes such as photoresist coating and peeling are required, making the entire process extremely complicated. Therefore, in order to simplify the microfabrication process, it has been desired to develop a heat-resistant material that can be microfabricated using direct light. As one of the above objects, a photosensitive heat-resistant material comprising polyamic acid and dichromate was proposed (Japanese Patent Publication No. 17374/1982).

According to this, a relief pattern of polyimide can be obtained by applying the material to a substrate, drying it, exposing it to light using a normal optical method, developing it, and then heat-treating it. However, this material has poor storage stability because it involves a dark reaction, and must be used immediately after being prepared as a photosensitive heat-resistant material by mixing dichromate.
Further, since the dichromate remains in the cured product, there is a drawback that the cured product has poor reliability as an insulating film.

Furthermore, JP-A-49-115541 describes, for example, the general formula: (wherein R is 0H2-0HOOOOH20H2-,0H
2-0(OH3)OOOOOH20H2-1α0H-OH
A photosensitive heat-resistant material has been proposed that is obtained by reacting a pyromellitic acid derivative represented by the structural formula (OOOOH20H2-, etc.) with a diamine. However, the synthesis process of the pyromellitic acid derivative is complicated and its purification is difficult, so the resulting photosensitive heat-resistant material has drawbacks such as being expensive.

Furthermore, JP-A No. 55-45746 describes that a photosensitive heat-resistant material can be obtained by completely reacting a polyamic acid with a monoepoxide having a photosensitive group such as methacrylglycidyl.

However, the reaction between eboxide and carboxylic acid is very complicated, such as requiring a reaction accelerator, and furthermore, there are drawbacks such as extremely poor storage stability after the reaction.

The present inventors have conducted intensive research aimed at overcoming the above-mentioned drawbacks and providing a photosensitive heat-resistant material that can be microfabricated and in which a relief pattern is formed by ordinary exposure means. As a result, (a) General formula (1) : (wherein, R□ is a divalent organic J (R2 represents a tetracarboxylic dianhydride residue containing at least 2 carbon atoms) and a polyamic acid represented by the general formula (2): (In the formula, R3 represents a monovalent organic group having an unsaturated bond) A polyimide precursor obtained by reacting an aziridine compound represented by the following in an organic solvent, and (b) general formula (3): % formula %(3) (wherein R4 represents a monovalent organic group having at least one unsaturated bond, or -OH.

and (c) a bisazide compound represented by general formula (4): % formula % (4) (in the formula, R5 represents a divalent organic group). However, the present invention was completed based on the discovery that the material is useful for insulating layers and passivation layers of solid-state devices as a material that can be microfabricated by direct light.

In the present invention, a new amide 7 group is generated by an addition reaction between a side chain nocarboxyl group in a polyamic acid produced by a reaction between a diamine component and a tetracarboxylic dianhydride and an unsaturated aziridine compound. This photosensitive heat-resistant material is characterized in that an unsaturated derivative represented by the general formula (3) is applied to the amide 7 group, and a bisazide compound is further added as a photocrosslinking component.

The polyamic acid represented by the general formula (1) used in the present invention can be obtained by reacting equimolar amounts of diamine and tetracarboxylic dianhydride. One is selected that is inert to carboxylic dianhydrides and is a good solvent for the polyamic acid to be obtained. For example, N,N-dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone, dimethylsulfoxide, hexamethylphosphoamide, and the like are preferably used. Further, the reaction is preferably maintained at a temperature of 8,000° C. or less, preferably from 20° C. to around room temperature, and is carried out for 2 to 10 hours.

Examples of the diamine which is one of the components constituting the polyamic acid represented by the general formula (1) used in the present invention include 4,4'-diaminodiphenyl ether, 4.4
'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfide, 4,4'-diaminodiphenylsulfone, 3,5'-diaminodiphenylsulfone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, benzidine, 0~tolidine, p-
7 Enylene diamine, m-phenylene diamine, 1.5
-diaminonaphthalene, 4t4'-diaminocyclohexylmethane, xylylene diamine, diaminophenyl indene, hexamethylene diamine, 1,6-di(p-aminophenyl)tetramethyldisiloxane, bis(γ-
aminopropyl)tetramethyldisiloxane, 4.41
-diaminostilbene, etc., and one or a mixture of two or more thereof can be used in the present invention.

Similarly, the other component, tetracarboxylic dianhydride, includes, for example, pyromellitic dianhydride, 2,2-
Bis(3,4-dicarboxyphenyl)p4>diacid t
a hydrate, bis(314-dicarboxyphenyl)nee f
Im anhydride, 5+&t4,4'-benzophenonetetracarboxylic dianhydride, 3.3',4.4'-biphenyltetracarpho>m dianhydride% 1121596-naphthalenetetracarboxylic dianhydride, 2, 2-His(dicarboxyphenyl)hexafluoropropanni ets
hydrate, 112.3.4-butanetetracarboxylic dianhydride, 1.2,6.4-cyclopentanetetracarboxylic dianhydride, 5-(2,5-dioxotetrahydrofuryl)-3-methyl Examples include -6-cyclohexene-1,2-dicarboxylic dianhydride, and one or a mixture of two or more thereof can be used in the present invention.

Examples of the tujiridine compound represented by the general formula (2) include Yoi0, and one or a mixture of two or more thereof can be used in the present invention.

It is desirable to obtain a polyimide precursor by reacting the carboxyl group of the side chain in the polyamic acid with the aziridine compound at a temperature of 60°C or less, preferably at a temperature of 20°C to room temperature for 2 to 6 hours.

The reaction proceeds quickly, so salts, bases, oxides,
The photosensitive heat-resistant material of the present invention has extremely excellent storage stability without requiring any additives such as peroxides that promote reactions.

In the reaction, the aziridine compound is preferably reacted in an amount of 0.2 to 1.2 equivalents, preferably 0.5 to 1.0 equivalents, relative to the side chain carboxyl group in the polyamic acid. If the amount is less than 0.2 equivalent, the crosslinking reaction upon exposure will not occur sufficiently, resulting in poor relief pattern forming ability. Moreover, if the air flow exceeds 1 or 2 blows, the cured product after heat treatment will be inferior in thermal stability.

A new secondary amine is generated by the above reaction, and by mixing the amine with the unsaturated derivative represented by the general formula (3), when X in the general formula (3) is 10H, O-
An unsaturated group is introduced into the polyimide precursor by the N bond, and in the case of the same (-NQO, the urea bond).

As a result, the crosslinking efficiency due to exposure increases as the number of photosensitive groups increases, and the difference in solubility between the exposed and unexposed areas increases, effectively achieving higher resolution.

Examples of the unsaturated derivatives represented by the general formula (3) used in the present invention include acrylic acid, methacrylic acid, cinnamic acid, cinnamylideneacetic acid, α-cyanocinnamic acid, vinylacetic acid, phenylmaleimidoacetic acid, glycidyl acrylate, and methacrylic acid. Examples include glycidyl acid, glycidyl cinnamate, phenylmaleimide acetate glycidyl methacroyl isocyanate, cinnamoyl isocyanate, vinyl isocyanate, iris isocyanate, and isopurbenyl isocyanate.

The above unsaturated derivative is added to the polyimide precursor in an amount of 0.2 to 1.0 equivalents based on the aziridine compound, and 1 to 2
It is preferable to react for a period of time. If the amount is less than 0.2 equivalent, no effect will be exhibited, and if the amount exceeds 1.0 equivalent, the thermal stability of the cured product will be poor.

Furthermore, the photosensitive heat-resistant material of the present invention can be changed by adding a bisazide compound represented by general formula (4), which is a photosensitive crosslinking agent, in an amount of 1 to 50% by weight based on the polyamide. If it is less than 1% by weight, the crosslinking effect will not be effectively exhibited, and if it exceeds 50 parts by weight, the cured product will have poor thermal stability.

Examples of the bisazide compound used in the present invention include 2,6-di(p-azidobenzal)-4-methylcyclohexanone, 2,6-di(p-azidobenzal)cyclohexanone, 4,4'-diazidobenzalacetone,
4.4'-Diazidostilbene, 4.4'-Diazidochalcone, 4.4'-Diazidobenzophenone, 2,8-
Examples include diazidoacridine, 4,4'-diazidodiphenylmethane, and 4,4'-diazidodiphenylamine, and one or a mixture of two or more of them can be used in the present invention.

The photosensitive heat-resistant material of the present invention can form a clear relief pattern even when exposed as it is, but by adding 0.01 to 10% by weight of a photosensitizer to the resin content, a marked increase in sensitivity can be achieved. It is possible. Such photosensitizers include, for example, cyanoacridine, 2-chloro-1,8-
Phthaloylnaphthalene, anthrathrone, 2'-bromo-1,2-benzaanthraquinone, 2'-chloro1.
2-benzanthraquinone, 1,2-benzanthraquinone, 1,8-dinitropyrene, 1-nitropyrene, 5
-Nitroacenaphthene, Michler's Katone, etc., and one type or a mixture of two or more of them can be used, but the present invention is not limited thereto.

The photosensitive heat-resistant material of the present invention is spin-coated onto a glass plate or silicon wafer, bleached at 50 to 9,000 ℃, irradiated with light or radiation through a mask having a predetermined pattern, and then N-methyl-2-pyrrolidone, By developing with a solvent such as N,N-dimethylacetamide or N,N-dimethylformamide, the unexposed areas are washed away and a sharp relief pattern on the end face is changed. Further, by performing a heat treatment at 200 to 400 degrees, a cured product having a good relief pattern with excellent heat resistance, chemical resistance, and electrical properties can be obtained.

The photosensitive heat-resistant material of the present invention can be stably stored at room temperature and protected from light for several months.

In addition, the photosensitive heat-resistant material of the present invention is not only useful as a material for insulating layers and passivation layers of solid-state devices such as semiconductors, or as a material for insulating films of magnetic heads, but also as a solder resist for printed circuits and as a highly heat-resistant material. It can also be applied to materials such as photoresists and other materials.

The present invention will be described in more detail below based on Examples, but the present invention is not limited to these Examples.

Reference Examples 1 to 6 Polyamic acids used in the present invention were synthesized according to the blending amounts of each component shown in Table 1. A typical synthesis method will be described below using Reference Example 1 as a representative example, but Reference Examples 2 to
6 can be similarly performed.

4,4'-shear mixing was carried out in a 100 ml four-hole flask equipped with a stirrer, a thermometer, a nitrogen inlet tube, and a calcium chloride tube. 3.5' keeping the solution at 2580; 4.
4'-benzophenone tetracarboxylic dianhydride 3.2
After adding 29 (0.01 mol) at once, the mixture was stirred at the above temperature for 4 hours to obtain a highly viscous polyamic acid.

Table 1 Example 1 2-(aziridinyl)ethylmethyl(0,0
After adding 16 mol) and reacting at 60°0 for 4 hours,
In addition, glycidyl methacrylate 2.62 (0,016
2,6-bis(p-azido7enyl)-4 was added to the reaction mixture and the reaction was continued for 4 hours at 60°O.
After adding 0.74 g (0,002 mol) of -methylcyclohexanone and stirring thoroughly at room temperature, the reaction mixture was filtered under pressure using a 1 μm glass filter to obtain the photosensitive heat-resistant material of the present invention.

The material was applied onto a glass plate and dried by heating at 60° 0 for 15 minutes, and then the material was irradiated with ultraviolet rays for 10 seconds using a predetermined photomask (super high pressure mercury lamp, distance 30 cm).

After exposure, a good relief pattern was obtained by immersing it in NMP for 60 to 120 seconds and developing it.

When heat treatment was then performed at 100°0 for 15 minutes, 200°0 for 15 minutes, and 350°0 for 60 minutes in a nitrogen atmosphere, no disturbance of the relief pattern occurred in the resulting cured product.

Examples 2 to 15 Photosensitive heat-resistant materials of the present invention were obtained by carrying out the same operations as in Example 1 according to the composition of each component shown in Table 2.

When this material was coated, exposed and developed in the same manner as in Example 1, good relief patterns were obtained in all cases.

When heat treatment was then performed under the same conditions as in Example 1, no blurring of the relief pattern occurred in any of the cured products.

Furthermore, thermogravimetric loss analysis was performed on the obtained cured product (in a nitrogen atmosphere, at a heating rate of 50o1',
The cured product obtained in Example 14 was heated at 690°C1 Example 15
In all of the cured products obtained, no decrease in weight was observed at temperatures below 400°O, except that decomposition started at 670°O.

In addition, all of the materials obtained in Examples 1 to 15 maintained stable turning properties even after being stored at room temperature and shielded from light for 6 months, and had excellent storage stability. ) l Shobu? 8 Po 2) Aoichi 1 Indication of the case Japanese Patent Application No. 5 B-87880 2 Name of the invention Photosensitive heat-resistant material 3 To representative Hitoshi Katayama of the person making the amendment Part 5, Subject of amendment (1) Description of the description tR6 of "Detailed Description of the Invention" Contents of Amendment (1) "Thujiridine" on page 10, line 9 of Memorandum M is corrected to "aziridine".

(2) Delete "For polyimide precursor" from the bottom two lines of page 13.

that's all

Claims (1)

[Claims] (1) (a) General formula (1): (In the formula, R is a divalent organic group, and R2 is a tetracarboxylic dianhydride residue containing at least 2 carbon atoms. ) and an aziridine compound represented by general formula (2): (wherein R3 represents a monovalent organic group having an unsaturated bond) in an organic solvent. A polyimide precursor and (b) general formula (8): % formula % (8) (wherein R4 represents a monovalent organic group having at least one unsaturated bond, and X is 10H1-O- 0H2-OH
(represents either -OH2 or -NOO)) and (Q) general formula (4): % formula % (4) (in the formula, R5 represents a divalent organic group) A photosensitive heat-resistant material mixed with a bisazide compound represented by (2) The photosensitive heat-resistant material according to claim (1), wherein the aziridine compound is blended within a range of 0.2 to 1.2 molarity with respect to the side chain carboxyl group in the polyamic acid. (8) Adding the unsaturated derivative to the aziridine compound (4)
) The above bisazide compound is a polyamic acid.