JP3080183B2 - Polyimide resin thin film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyimide resin thin film used for an interlayer insulating film, an optical thin film, a passivation film, a soft error prevention film, a liquid crystal alignment film and the like of a semiconductor device.

[0002]

As one method of forming the polyimide resin film containing fluorine on the tetracarboxylic acid dianhydride and a diamine as a raw material monomer of the Related Art Polyimide is especially open flat 3-
As seen in 6363 discloses, for example, pyromellitic dianhydride and 2,2-bis (4-aminophenyl) using a hexafluoropropane evaporated both monomers in a vacuum, polymerization on the substrate so There has been proposed a method of forming a polyimide resin thin film. Further, as disclosed in Japanese Patent Application No. 1-120117 as a method for forming a polyimide resin thin film containing both monomers as fluorine, for example, both monomers are reacted in a polar organic solvent such as N, N-dimethylformamide. A method has been proposed in which a polyamic acid solution is prepared, a polyamic acid solution is spin-coated on an aluminum substrate, and heated and fixed stepwise under a nitrogen atmosphere.

[0003]

As a polyimide film used as a semiconductor insulating film, a material having a smaller relative dielectric constant is desired in order to reduce charge-up. However, the above-mentioned method of forming a polyimide resin thin film containing fluorine in one of the monomers yields only a polyimide resin thin film having a relatively large dielectric constant, and also contains fluorine in both of the monomers and is formed by spin coating and heating. Is not a very suitable method for an insulating film because the adhesive force between the formed polyimide film and the substrate is small. An object of the present invention is to solve the above problems and to provide a polyimide resin thin film having a small relative dielectric constant and a large adhesive force with a substrate.

[0004]

SUMMARY OF THE INVENTION In general, the present invention relates to a polyimide resin thin film having the following general formula (1):

Embedded image [Wherein R ₁ is the following formula (Formula 2):

Embedded image R ₂ is any of the groups represented by the following formulas (Formula 3):

Embedded image Wherein Rf is a fluorine or perfluoroalkyl group, and X is the following formula (Formula 4):

Embedded image (Where Rf 'is a perfluoroalkylene group, and n is a group of 1 to 10), and a polyimide containing a repeating unit represented by the following formula: In a thin film made of a polyimide resin as a constituent element, the thin film has the following general formula (Formula 5):

Embedded image Tetracarboxylic acids represented by [wherein R ₁ is the general formula (Formula 1) in the same meaning as R _1], or an acid component mainly composed of a derivative represented by the following general formula (Formula 6):

Embedded evaporation respectively and H ₂ N-R ₂ -NH ₂ diamine composed mainly of diamine represented by [wherein R ₂ is the general formula (Formula 1) R ₂ as synonymous in] component And then polymerized on a substrate to form the polyimide resin film.

[0005] The tetracarboxylic acid or its derivative used for forming the polyimide film of the present invention may be a compound in which all monovalent elements bonded to carbon such as an alkyl group or a phenyl ring in the molecule are fluorine or perfluoroalkyl groups. Anything may be used as long as it is set. Examples of the tetracarboxylic acid and its derivatives such as acid anhydrides, acid chlorides, and esterified compounds include the following. Here, examples of tetracarboxylic acids include 1,4-difluoropyromellitic acid and 1-trifluoromethyl-4.
-Fluoropyromellitic acid, 1,4-di (trifluoromethyl) pyromellitic acid, 1,4-di (pentafluoroethyl) pyromellitic acid, hexafluoro-3,3 ′,
4,4'-biphenyltetracarboxylic acid, hexafluoro-3,3 ', 4,4'-benzophenonetetracarboxylic acid, 2,2-bis (3,4-dicarboxytrifluorophenyl) hexafluoropropane, 3-bis (3,4-dicarboxytrifluorophenyl) hexafluoropropane, 1,4-bis (3,4-dicarboxytrifluorophenoxy) tetrafluorobenzene,
Hexafluoro-3,3 '(or 4,4') oxybisphthalic acid and the like. Among these, 1,4-di (trifluoromethyl) pyromellitic dianhydride, which is a fluorinated dianhydride having a fluoroalkyl group introduced into a benzene ring of pyromellitic dianhydride, 1,4-di ( A method for producing (pentafluoroethyl) pyromellitic dianhydride and the like is described in Japanese Patent Application No. 63-165056.

Examples of the diamine that can be used in the present invention include an alkyl group excluding an amino group in the molecule, and a fluorine or perfluoroalkyl group for all monovalent elements bonded to carbon such as a phenyl ring. Any substance may be used as long as it is 3,4,5,6-tetrafluoro-1,2-phenylenediamine, 2,4,5,6-tetrafluoro-1,3-phenylenediamine, 2,3 ,
5,6-tetrafluoro-1,4-phenylenediamine, 4,4'-diaminooctafluorobiphenyl, bis (2,3,5,6-tetrafluoro-4-aminophenyl) ether, bis (2,3 5,6-tetrafluoro-4-aminophenyl) sulfone, hexafluoro-
2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl and the like.

In the present invention, not only a tetracarboxylic acid component or a diamine is used as a single compound, but also a mixture of a plurality of diamines and a tetracarboxylic acid component may be used. In this case, the sum of the number of moles evaporated per unit time of a plurality or a single diamine component and the sum of moles evaporated per unit time of a plurality or a single tetracarboxylic acid component should be equal or almost equal. . In order to achieve the intended purpose, it is preferable that all the constituent elements of the polyimide are perfluorinated polyimide, but even if a part of the non-perfluorinated acid component or diamine component is used as a raw material, the It is not a big problem if the ratio is small. The degree of vacuum for evaporating the raw material monomer and polymerizing it on the substrate is 1 × 10 ⁻⁴ to 1 × 10 ⁻⁷ To.
rr is preferred.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings, but the present invention is not limited to these embodiments.

FIG. 1 is a sectional view of an example of an apparatus for producing a thin film according to the present invention. Reference numeral 1 denotes a growth chamber, and the inside of the growth chamber 1 is connected to an evacuation system 2 of an external vacuum pump. At the same time, a substrate 3 on which a polyimide resin vapor deposition film is to be formed in the growth chamber 1 is held on a substrate holder 4,
Is heated to a desired temperature by a heater 5 provided on the back surface of the substrate holder 4, and a film thickness formed on the substrate 3 is measured by a film thickness monitor 6 installed near the substrate 3. did. Further, a K cell 7 for evaporating the raw material monomers a and b of the polyimide resin was provided in the lower part of the growth chamber 1 so as to face the substrate 3. In the drawings, reference numerals 8 and 9 denote shutters interposed between the substrate 3 and the K cell 7. Next, an example of forming a polyimide resin film by polymerization using the above-described apparatus will be described.

Example 1 First, 1,4-bis (3,4-dicarboxytrifluorophenoxy) tetrafluorobenzene dianhydride was added to one of the K cells 7 and 2,4,5,6-tetrafluoro-
After filling with 1,3-phenylenediamine and closing the shutters 8 and 9, the total pressure of the atmosphere gas in the growth chamber 1 is set to 1 × 10 ⁻⁷ Torr using the vacuum exhaust system 2. Next, the raw material monomers a and b from the K cell are monitored by the film thickness monitor 6.
The acid dianhydride was heated to 80 ° C ± 2 ° C while measuring the evaporation rate of
And the diamine is heated to 70 ° C. ± 2 ° C. Next, after the raw material monomers a and b reach the target temperature and the required evaporation rate is obtained, the shutters 8 and 9 are opened, and the raw material monomers a and b are deposited on the substrate 3 at a growth rate of 60 A / min to a thickness of 2 A.
Then, the shutters 8 and 9 are closed, and the substrate 3 is heated to a temperature of 200 ° C. by the heater 5 and held for a predetermined time to cause a polymerization reaction of polyimide on the substrate 3 so that the substrate 3 is placed on the substrate 3. A polyimide resin thin film was formed, and the relative dielectric constant was examined. As a result, the relative dielectric constant is 2.7 or less (10 k
Hz). The raw material monomers a and b were evaporated at a ratio of 1: 1 by adjusting the evaporation rate so as to form a stoichiometric thin film. The obtained polyimide resin thin film is dense and high-purity and has good adhesion to the substrate.Electrical insulation, chemical resistance, and other physical properties such as heat resistance are not much brighter than those obtained by the conventional wet method. Was.

Example 2 Next, 1,4-bis (3,4-dicarboxytrifluorophenoxy) tetrafluorobenzene dianhydride was used as a raw material monomer a at 80 ° C. ± in the same manner as in Example 1.
The mixture was heated and evaporated at 2 ° C., and bis (2,2
3,5,6-tetrafluoro-4-aminophenyl) ether is heated and evaporated at 70 ° C. ± 2 ° C.
The substrate 3 is deposited to a thickness of 2000 A at a deposition rate of A / min. Thereafter, the substrate 3 is heated at a temperature of 200 ° C. by a heater 5 and held for a predetermined time to cause a polymerization reaction of polyimide to contain fluorine on the substrate 3. The resulting polyimide resin thin film was formed, and the relative dielectric constant was examined. As a result, the relative dielectric constant was 2.7 or less (10 kHz).

Comparative Example 1 For comparison with the above-mentioned example, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride was used as the starting monomer a, and 2-
Using bis [4- (4-aminophenoxy) phenyl] hexafluoropropane and the same apparatus and the same method as in the previous example, both monomers were 2,000 A thick on the substrate 3.
Then, the substrate 3 is heated to a temperature of 300 ° C. by the heater 5 and held for a predetermined time to cause a polymerization reaction of polyimide on the substrate 3 to form a polyimide resin thin film on the substrate 3 and to examine a relative dielectric constant. Was. As a result, the relative dielectric constant is 2.9-
3.1 (10 kHz).

[0013]

As described above, according to the present invention, there is provided a method for forming a polyimide resin thin film by evaporating an aromatic acid component and an aromatic diamine as raw material monomers in a vacuum and polymerizing them on a substrate. Since both the raw material monomers of the polyimide resin are fluorine-containing monomers, there is an effect that a polyimide resin thin film having a small relative dielectric constant can be formed on a substrate by an evaporation polymerization method.

[Brief description of the drawings]

FIG. 1 is a sectional view of an example of an apparatus for producing a polyimide resin thin film of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Growth chamber, 2 ... Vacuum exhaust system, 3 ... Substrate, 4 ... Substrate holder, 5 ... Heater, 6 ... Film thickness monitor, 7 ... K cell, 8 and 9 ... Shutter, a and b ... Raw material monomer

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Toru Matsuura 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-3-6363 (JP, A) JP-A-Hei 2-56274 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08J 5/18 CFG C08G 76/10 C08L 77/06 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] 1. A compound represented by the following general formula (1): [Wherein R ₁ is the following formula (Chemical formula 2): Any of the groups represented by the formula, R ₂ is represented by the following formula (Formula 3): Wherein Rf is a fluorine or perfluoroalkyl group, and X is a group represented by the following formula: Wherein Rf 'is a perfluoroalkylene group, and n is any one of groups represented by 1 to 10). In a thin film made of a polyimide resin as a constituent element, the thin film has the following general formula (Formula 5): Tetracarboxylic acids represented by [wherein R ₁ is the general formula (Formula 1) in the same meaning as R _1], or an acid component mainly composed of a derivative represented by the following general formula (Formula 6): [ of 6] H ₂ N-R ₂ -NH ₂ diamine each evaporating a diamine component mainly comprising represented by [wherein R ₂ is formula 1 in the same meaning as R ₂ in] A polyimide resin thin film obtained by polymerizing on a substrate to form the polyimide resin film.