Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
2001-03-28
2003-02-11
Truong, Duc (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
C528S182000, C528S190000, C528S192000, C528S201000, C528S205000, C528S272000, C528S288000, C528S308600, C528S422000, C528S425000
Reexamination Certificate
active
06518390
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a precursor of a heat resistant resin, a heat resistant resin, an insulating film and a semiconductor device. More particularly, the present invention relates to a precursor providing a polybenzoxazole resin which exhibits excellent electric, mechanical and physical properties, in particular, excellent properties under heating, and is advantageously used for insulating interlayer films and films for protecting surfaces in semiconductors, insulating interlayer films of multi-layer circuits, cover coats of flexible copper clad laminates, solder resist films and liquid crystal-aligning films, a polybenzoxazole resin which is obtained from the above precursor and has the above characteristics, an insulating film comprising the polybenzoxazole resin and a semiconductor device comprising the insulating film.
2. Description of Related Art
As the insulating interlayer films, films of oxides (films of SiOx) prepared in accordance with the chemical vapor deposition process (the CVD process) are mainly used at present. However, inorganic insulating films such as films of oxides have a great permittivity. To achieve a high speed and a high performance of semiconductors, an insulating film having a low permittivity is desired and films of organic materials have been examined as the candidates. As the organic material used for semiconductors, heat resistant resins having excellent electric, mechanical and physical properties are proposed.
For example, application of polybenzoxazole resins as the above heat resistant resin has been attempted. To obtain a polybenzoxazole resin, in general, a precursor of the polybenzoxazole resin is prepared from a bisaminophenol compound and a dicarboxylic acid compound. An article such as a film is prepared by using the precursor and the precursor formed into the article is then converted into a polybenzoxazole resin. Examples of the polybenzoxazole resin include polybenzoxazole resins synthesized from 4,4′-diamino-3,3′-dihydroxybiphenyl and terephthalic acid and polybenzoxazole resins synthesized from 4,4′-diamino-3,3′-dihydroxy-biphenyl and 4,4′-biphenyldicarboxylic acid.
As described above, heat resistance can be easily improved by providing a rigid skeleton structure to a resin. However, this causes a decrease in the solubility of a precursor of the resin into organic solvents and working of the resin such as preparation of a film in accordance with a coating process becomes very difficult. On the other hand, for example, a polybenzoxazole resin prepared from 2,2-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane and isophthalic acid can be worked into various shapes since the precursor is soluble in organic solvents. However, when the above precursor is converted into a polybenzoxazole resin, heat resistance of the obtained resin tends to be inferior to the former polybenzoxazole resins.
Since the above heat resistant resins are examined as materials to replace inorganic compounds in applications such as insulating interlayer films in semiconductors, the improvement in the heat resistance of the heat resistant resins is increasingly required. It is necessary that heat resistance be further improved while the resin is kept soluble in organic solvents so that excellent processability is maintained.
SUMMARY OF THE INVENTION
The present invention has objects of providing a precursor of a polybenzoxazole resin which exhibits excellent processability due to excellent solubility in solvents and, after ring closure, excellent heat stability in applications and provides a resin which exhibits excellent electric, physical and mechanical properties and is advantageously used for insulating interlayer films of semiconductor devices; a heat resistant resin which is obtained from the above precursor and has the above characteristics; an insulating film comprising the polybenzoxazole resin; and a semiconductor device comprising the insulating film.
As the result of extensive studies by the present inventors to achieve the above objects, it was found that a precursor of a polybenzoxazole resin having a specific structure which is obtained by introducing a three-dimensionally crosslinking functional group into the structure of the main chain maintains the solubility in organic solvents and can be converted into a resin having high heat resistance by heating due to a three-dimensional structure formed by a combination of a conventional condensation reaction (the ring closure reaction with elimination of water) and the crosslinking reaction. The present invention has been completed based on the knowledge.
The present invention provides:
(1) A precursor of a polybenzoxazole resin which comprises a crosslinking group in a molecule;
(2) A precursor of a polybenzoxazole resin described in (1), which comprises a structure represented by general formula [1]:
wherein R
1
to R
4
each independently represent hydrogen atom or a monovalent organic group, X represents a tetravalent group selected from groups represented by following formulae (A), two groups represented by X may be the same with or different from each other, Y represents at least one divalent group selected from groups represented by following formulae (B), (C), (D) and (E), Z represents a divalent group selected from groups represented by following formulae (F), m and n each represent an integer satisfying relations of m>0, n≧0, 2≦m+n≦1,000 and 0.05≦m/(m+n)≦1 and arrangement of repeating units may be a block arrangement or a random arrangement;
Formulae (A)
Formulae (B)-1
Formulae (B)-2
Formulae (C)-1
Formulae (C)-2
Formulae (D)
Formula (E)
Formulae (F)
wherein X
1
in formulae (A) and (F) represents a divalent group selected from groups represented by following formulae (G):
Formula (G)
R in formulae (C) represents an alkyl group or a monovalent group selected from groups represented by formulae (H):
Formulae (H)
and hydrogen atoms on a benzene ring in groups represented by Formulae (A), (B), (C), (D), (E), (F) and (G) may be substituted with at least one atom or group selected from alkyl groups having 1 to 4 carbon atom, fluorine atom and trifluoromethyl group;
(3) A polybenzoxazole resin which is obtained from a precursor of a polybenzoxazole resin described in any of (1) and (2) by a condensation reaction and a crosslinking reaction;
(4) An insulating film which comprises a polybenzoxazole resin described in (3); and
(5) A semiconductor device which comprises at least one film which is selected from insulating interlayer films in multi-layer wiring and films for protecting surfaces and comprises an in sulating film described in (4).
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The precursor of a polybenzoxazole resin of the present invention comprises a crosslinking group in the molecule. Examples of the crosslinking group include substituent groups which can be three-dimensionally crosslinked such as ethynyl group, substituted ethynyl groups, internal acetylene group, biphenylene group, cyanato group, maleimide group, nadimide group and propargyl group. The precursor may have one or more crosslinking groups in the molecule.
As the precursor of a polybenzoxazole described above, compounds comprising the structure represented by the above general formula [1] are preferable.
The precursor of a polybenzoxazole resin comprising the structure represented by general formula [1] can be obtained in accordance with a conventional process such as the acid chloride process, the activated ester process and the condensation reaction in the presence of an agent for condensation with elimination of water such as polyphosphoric acid and dicyclohexylcarbodiimide using at least one compound selected from bisaminophenol compounds having a tetravalent group selected from the groups represented by formulae (A) and at least one dicarboxylic acid having a crosslinking group selected from the divalent groups represented by formulae (B), (C), (D) and (E). A combination
Fujimoto Masanori
Higashida Nobuhiro
Ishikawa Tadahiro
Okanuma Masako
Saito Hidenori
Smith , Gambrell & Russell, LLP
Sumitomo Bakelite Company Ltd.
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