JPH04239037A - Production of multilayer polyimide film - Google Patents

Abstract

PURPOSE:To obtain the title film comprising a polyimide film soluble in an organic solvent and, formed thereon, another polyimide film and having low permittivity and excellent transparency by forming the upper-layer film after the soluble polyimide film is heat-treated at a specified temperature. CONSTITUTION:A process for producing a multilayer polyimide film by forming a polyimide film on another polyimide film soluble in an organic solvent, wherein a polyimide film (e.g. one produced from 2,2'-bis(trifluoromethyl)-4,4'- diaminobiphenyl and 2,2-bis(3,4-dicarboxyphenyl)-hexafluoropropane dianhydride) soluble in an organic solvent (e.g. N,N-dimethylacetamide) is heat-treated at 380 deg.C or above before another polyimide film is formed thereon.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyimide multilayer film made of soluble polyimide, and more particularly to a method for producing a polyimide multilayer film for use in electronic parts, electronic/optical parts, and optical parts.

0002

BACKGROUND OF THE INVENTION Polyimide has been widely used mainly in the aerospace and aerospace fields because of its excellent heat resistance. Recently, it has been used as an interlayer insulating film for electronic components and as a material for multilayer wiring boards, taking advantage of its excellent heat resistance, which allows it to withstand semiconductor process temperatures. These polyimides are required to have a low dielectric constant from the viewpoint of increasing signal speed. Polyimide is also beginning to be expected to be used as an optical waveguide in electronic/optical components and optical components, and polyimide is required to have low optical transmission loss, that is, transparency. Recently, various polyimides having such low dielectric constant and transparency have been developed. For example, Sampe Journal (S
AMPE JOURNAL), July/August issue (198
5), page 28 reports some examples of transparent polyimides. It is stated that one of the characteristics of these transparent polyimides is that they are soluble in solvents. Furthermore, the present inventors disclosed a transparent fluorinated polyimide with a low dielectric constant in Japanese Patent Application No. 1-201170. Many of these polyimides are soluble in solvents.

By the way, when these low dielectric constant, transparent polyimides are used as interlayer insulating films or optical waveguides, it is often required to have a multilayer structure. That is, it is necessary to form at least one more polyimide film on top of the polyimide film. However, since these low dielectric constant, transparent polyimides have the property of being soluble in solvents, it is difficult to form them into multilayers, and as far as we have investigated, multilayers of these have not been realized. The present inventors utilized the difference in solubility in solvents between polyimide and its precursor, polyamic acid, to produce these polyimide multilayer films, using a solvent that is insoluble in polyimide but soluble in polyamic acid. We have successfully produced a polyimide multilayer film by preparing a polyamic acid solution and forming a polyimide film on the top layer of soluble polyimide. Although this manufacturing method is an interesting method for forming a multilayer film of soluble polyimide, it also has the disadvantage that the same solvent cannot be used for polyamic acid and polyimide.

0004

SUMMARY OF THE INVENTION It has been impossible to form a multilayer film of soluble polyimide using the same solvent. An object of the present invention is to provide a simple method for producing a multilayer film of soluble polyimide having a low dielectric constant and excellent transparency.

[0005]

[Means for Solving the Problems] To summarize the present invention, the present invention relates to a method for producing a polyimide multilayer film, in which a polyimide film is formed on the upper layer of a polyimide film soluble in an organic solvent. In manufacturing, a polyimide film soluble in an organic solvent is formed by heat treatment at 380° C. or higher.

In order to achieve the above object, the present inventors investigated the relationship between the heat treatment temperature of soluble polyimide and its solubility in solvents, and found that by increasing the heat treatment temperature of polyimide to a certain temperature or higher, the solubility in solvents can be improved. The present invention was completed based on the discovery that multi-layering is possible.

[0007] As the soluble polyimide used in the present invention, all soluble polyimides can be used. For example, among the polyimides, polyimide copolymers, and polyimide mixtures produced from tetracarboxylic acids or derivatives thereof and diamines shown below, those soluble in solvents may be mentioned.

Examples of tetracarboxylic acids and their derivatives such as acid anhydrides, acid chlorides, and esters include the following. Here, an example of a tetracarboxylic acid will be given.

(trifluoromethyl)pyromellitic acid,
Di(trifluoromethyl)pyromellitic acid, di(heptafluoropropyl)pyromellitic acid, pentafluoroethylpyromellitic acid, bis{3,5-di(trifluoromethyl)phenoxy}pyromellitic acid, 2,3,3 ′、
4'-biphenyltetracarboxylic acid, 3,3',4,4
'-Tetracarboxydiphenyl ether, 2,3',
3,4'-tetracarboxydiphenyl ether, 3,
3',4,4'-benzophenonetetracarboxylic acid, 2
, 3,6,7-tetracarboxynaphthalene, 1,4,
5,7-tetracarboxynaphthalene, 1,4,5,6
-Tetracarboxynaphthalene, 3,3',4,4'-
Tetracarboxydiphenylmethane, 3,3',4,4
'-Tetracarboxydiphenyl sulfone, 2,2-bis(3,4-dicarboxyphenyl)propane, 2,2
-bis(3,4-dicarboxyphenyl)hexafluoropropane, 5,5'-bis(trifluoromethyl)-
3,3',4,4'-tetracarboxybiphenyl, 2
,2',5,5'-tetrakis(trifluoromethyl)
-3,3',4,4'-tetracarboxybiphenyl,
5,5'-bis(trifluoromethyl)-3,3',4
, 4'-tetracarboxydiphenyl ether, 5,5
'-Bis(trifluoromethyl)-3,3',4,4'
-Tetracarboxybenzophenone, bis{(trifluoromethyl)dicarboxyphenoxy}benzene, bis{(trifluoromethyl)dicarboxyphenoxy}(
trifluoromethyl)benzene, bis(dicarboxyphenoxy)(trifluoromethyl)benzene, bis(dicarboxyphenoxy)bis(trifluoromethyl)benzene, bis(dicarboxyphenoxy)tetrakis(
trifluoromethyl)benzene, 3,4,9,10-tetracarboxyperylene, 2,2-bis{4-(3,4
-dicarboxyphenoxy)phenyl}propane, butanetetracarboxylic acid, cyclopentanetetracarboxylic acid, 2,2-bis{4-(3,4-dicarboxyphenoxy)phenyl}hexafluoropropane, bis{(trifluoromethyl) dicarboxyphenoxy}biphenyl, bis{(trifluoromethyl)dicarboxyphenoxy}bis(trifluoromethyl)biphenyl, bis{(
trifluoromethyl)dicarboxyphenoxy}diphenyl ether, bis(dicarboxyphenoxy)bis(
trifluoromethyl)biphenyl, etc.

[0010] Examples of diamines include the following. m-phenylenediamine, 2,4-diaminotoluene, 2,4-diaminoxylene, 2,4-diaminodurene, 4-(1H,1H,11H-eicosafluoroundecanoxy)-1,3-diaminobenzene, 4-
(1H,1H-perfluoro-1-butanoxy)-1,
3-diaminobenzene, 4-(1H,1H-perfluoro-1-heptanoxy)-1,3-diaminobenzene,
4-(1H,1H-perfluoro-1-octanoxy)
-1,3-diaminobenzene, 4-pentafluorophenoxy-1,3-diaminobenzene, 4-(2,3,5
, 6-tetrafluorophenoxy)-1,3-diaminobenzene, 4-(4-fluorophenoxy)-1,3-
Diaminobenzene, 4-(1H,1H,2H,2H-perfluoro-1-hexanoxy)-1,3-diaminobenzene, 4-(1H,1H,2H,2H-perfluoro-1-dodecanoxy)-1, 3-diaminobenzene, p
-phenylenediamine, (2,5-)diaminotoluene, 2,3,5,6-tetramethyl-p-phenylenediamine, (2,5-)diaminobenzotrifluoride,
Bis(trifluoromethyl)phenylenediamine, diaminotetra(trifluoromethyl)benzene, diamino(pentafluoroethyl)benzene, 2,5-diamino(perfluorohexyl)benzene, 2,5-diamino(perfluorobutyl)benzene, benzidine, 2,2
'-Dimethylbenzidine, 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 3,3',5,5'-tetramethylbenzidine, 3,3'-diacetylbenzidine ,2,2
'-Bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-bis(trifluoromethyl)-
4,4'-diaminobiphenyl, octafluorobenzidine, 4,4'-diaminodiphenyl ether, 4,4
'-Diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 2,2-bis(p-aminophenyl)propane, 3,3'-dimethyl-4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4 ,4'-
Diaminodiphenylmethane, 1,2-bis(anilino)
Ethane, 2,2-bis(p-aminophenyl)hexafluoropropane, 1,3-bis(anilino)hexafluoropropane, 1,4-bis(anilino)octafluorobutane, 1,5-bis(anilino)deca Fluoropentane, 1,7-bis(anilino)tetradecafluoroheptane, 2,2'-bis(trifluoromethyl)-4,
4'-diaminodiphenyl ether, 3,3'-bis(
trifluoromethyl)-4,4'-diaminodiphenyl ether, 3,3',5,5'-tetrakis(trifluoromethyl)-4,4'-diaminodiphenyl ether, 3,3'-bis(trifluoromethyl)- 4,4'-
Diaminobenzophenone, 4,4''-diamino-p-
Terphenyl, 1,4-bis(p-aminophenyl)benzene, p-bis(4-amino-2-trifluoromethylphenoxy)benzene, bis(aminophenoxy)bis(trifluoromethyl)benzene, bis(aminophenoxy) ) tetrakis(trifluoromethyl)benzene,
4,4'''-diamino-p-quarterphenyl, 4
, 4'-bis(p-aminophenoxy)biphenyl, 2
,2-bis{4-(p-aminophenoxy)phenyl}
Propane, 4,4'-bis(3-aminophenoxyphenyl)diphenylsulfone, 2,2-bis{4-(4-
aminophenoxy)phenyl}hexafluoropropane, 2,2-bis{4-(3-aminophenoxy)phenyl}hexafluoropropane, 2,2-bis{4-(2
-aminophenoxy)phenyl}hexafluoropropane, 2,2-bis{4-(4-aminophenoxy)-3
,5-dimethylphenyl}hexafluoropropane, 2
,2-bis{4-(4-aminophenoxy)-3,5-
ditrifluoromethylphenyl}hexafluoropropane, 4,4'-bis(4-amino-2-trifluoromethylphenoxy)biphenyl, 4,4'-bis(4-amino-3-trifluoromethylphenoxy)biphenyl, 4 , 4'-bis(4-amino-2-trifluoromethylphenoxy)diphenylsulfone, 4,4'-bis(
3-amino-5-trifluoromethylphenoxy)diphenylsulfone, 2,2-bis{4-(4-amino-3
-trifluoromethylphenoxy)phenyl}hexafluoropropane, bis{(trifluoromethyl)aminophenoxy}biphenyl, bis[{(trifluoromethyl)aminophenoxy}phenyl]hexafluoropropane, diaminoanthraquinone, 1,5-diaminonaphthalene , 2,6-diaminonaphthalene, bis{2-[(
aminophenoxy)phenyl]hexafluoroisopropyl}benzene, etc.

The polyimide layer formed on the soluble polyimide layer is not particularly limited and any polyimide can be used.

As a method for manufacturing the polyimide multilayer film of the present invention, the following method can be used, for example. silicon, quartz,
A solution of soluble polyimide or its precursor, polyamic acid, dissolved in a solvent is applied onto a substrate such as polyimide by a method such as spin coating, and cured at a predetermined temperature condition to make it insoluble in organic solvents. Obtain a membrane. Next, a polyamic acid solution, which is a precursor of polyimide for forming a second layer on the first layer polyimide film, is obtained. After applying this polyamic acid solution by a method such as spin coating, it is cured to obtain a second layer. If necessary, a third or higher multilayer film is formed in the same manner.

[0013] The present invention is characterized in that the heat treatment temperature of the soluble polyimide is kept constant, and for other manufacturing methods, general polyimide multilayer film manufacturing methods can be used.

[0014]

EXAMPLES The present invention will be explained in more detail using some examples below, but the present invention is not limited to these examples.

Example 1 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl as the diamine and 2,2' as the acid anhydride were deposited on a silicon wafer with a diameter of 3 inches whose surface was a silicon oxide layer. -bis(3,4-dicarboxyphenyl)-
15 wt% of polyamic acid, a precursor of soluble polyimide produced using hexafluoropropane dianhydride
The film thickness after heating the N,N-dimethylacetamide solution is 1
After coating by spin coating to a thickness of 0 μm, heat treatment was performed to a maximum temperature of 380° C. or higher. In this way, a polyimide film obtained from the first layer of soluble polyimide was produced. Next, the same polyamic acid solution was applied by spin coating so that the film thickness after heating was 10 μm, and then heat treatment was performed at a maximum temperature of 350° C. As a result, a two-layer film of soluble polyimide with a film thickness of 20 μm was formed. As a result of observing the cross section of the two-layer film using a scanning electron microscope, it was confirmed that the interface between both layers was formed without being attacked by the solvent.

Examples 2 to 9 In Example 1, 2,2′-bis(trifluoromethyl)-
Using polyamic acid produced from 4,4'-diaminobiphenyl and the acid anhydrides listed in Table 1, the same procedure as in Example 1 was carried out, and a two-layer polyimide film with a film thickness of 20 μm could be formed. .

[0017]

[Table 1]
Table 1────────────────
────────────────────── Example 1st layer soluble polyimide precursor 2nd
Used for layer polyimide precursor
Acid anhydride used on the body Acid anhydride used──────────────────────
──────────────── Example 2
6FDA:PMDA=1:0 6FDA:PMD
A=9:1────────────────────
──────────────── Example 3
6FDA:PMDA=1:0 6FDA:PM
DA=8:2────────────────────
────────────────── Example 4
6FDA:PMDA=1:0 6FDA:P
MDA=7:3──────────────────
────────────────── Example 5
6FDA:PMDA=1:0 6FDA:
PMDA=6:4──────────────────
──────────────────── Example 6
6FDA:PMDA=9:1 6FDA
:PMDA=1:0────────────────
──────────────────── Example 7 6FDA:PMDA=9:1 6FD
A: PMDA=9:1────────────────
────────────────────── Example 8 6FDA:PMDA=9:1 6F
DA:PMDA=8:2──────────────
────────────────────── Example 9 6FDA:PMDA=8:2 6
FDA:PMDA=7:3──────────────
────────────────────────
*6FDA; 2,2-bis(3,4-dicarboxyphenyl)-hexaflu
Olopropane dianhydride *PMDA; Pyromellitic dianhydride

Example 10 The polyimide two-layer film obtained in Example 1 was heat-treated at 380° C. for 1 hour, and then a polyamic acid solution, which was a precursor of the soluble polyimide used in Example 1, was heated on the upper layer. After coating by spin coating to a film thickness of 10 μm, heat treatment was performed at a maximum temperature of 350°C. As a result, a three-layer film of soluble polyimide with a film thickness of 30 μm was formed. As a result of observing the cross section of the three-layer film using a scanning electron microscope, it was confirmed that the interface between each layer was formed without being attacked by the solvent.

Comparative Example 1 An attempt was made to fabricate a multilayer film in the same manner as in Example 1, except that the heat treatment temperature was 350° C. and the heat treatment time was 1 hour. However, the first layer of soluble polyimide film was dissolved, and a multilayer film could not be produced.

[0020]

[Effects of the Invention] As explained above, according to the present invention, 1
A polyimide multilayer film can be easily provided by heat-treating the soluble polyimide layer at 380° C. or higher. Using the multilayer film according to the present invention, it is possible to manufacture low optical loss buried polyimide optical waveguides, low dielectric constant polyimide multilayer wiring boards, and the like.

Claims (2)

[Claims] Claim 1: In the production of a polyimide multilayer film in which a polyimide film is formed on the top layer of a polyimide film soluble in organic solvents, the polyimide film soluble in organic solvents is heated at 380°C.
A method for producing a polyimide multilayer film, characterized in that it is formed by performing the heat treatment described above. [Claim 2] At least one of the organic solvent-soluble polyimide films is 2,2'-bis(trifluoromethyl).
2. The method for producing a polyimide multilayer film according to claim 1, wherein the polyimide, polyimide copolymer, or polyimide mixture contains -4,4'-diaminobiphenyl as a synthetic raw material.