Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Reexamination Certificate
2002-05-31
2004-06-15
Hightower, P. Hampton (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
C528S125000, C528S126000, C528S171000, C528S172000, C528S173000, C528S174000, C528S179000, C528S182000, C528S183000, C528S188000, C528S332000, C528S335000, C528S336000, C528S338000, C528S327000, C528S339000, C525S420000
Reexamination Certificate
active
06750317
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to polyhydroxyamides that can be used for preparing highly crosslinked polymers and to temperature stable polymers prepared from these polyhydroxyamides. The invention further relates to polymers that have been three-dimensionally crosslinked using the polyhydroxyamides.
In microelectronics, in the automobile industry, in mechanical engineering, and in the aerospace industry, chemically-inert, high-heat-resistance polymers are needed as protective and insulating coats. In microelectronics, such polymers are used, for example, as a dielectric between the chip and a metallization level or between two metal levels in a chip: for example, in multichip modules or in memory chips and logic chips. Furthermore, such polymers are also used as a buffer coat between chip and housing. In the automobile industry, in mechanical engineering, and in the aerospace industry, such chemically-inert, high-heat-resistance polymers are needed for producing weather-resistant protective coats.
Polybenzoxazoles exhibit a high level of temperature stability and great chemical resistance. They are generally prepared from polyhydroxyamides that are readily soluble in organic solvents, such as N-methyl-pyrrolidone. The solutions can be applied to surfaces by spin coating, by dipping or by brush methods. The solvent can be removed subsequently by heating, which can be accompanied or followed by cyclization of the polyhydroxyamide to the polybenzoxazole, with elimination of water, in accordance with the reaction depicted below, so giving a polymer having the properties described above.
Polyhydroxyamides that are readily soluble in organic solventsand exhibit good temperature stability are described, for example, in European Patent Application No. EP 0 317 942 (which corresponds to U.S. Pat. No. 4,845,183), European Patent No. EP 0 512 339 B1 (which corresponds to U.S. Pat. No. 5,376,499), German published, non-prosecuted Application No. DE 37 17 212 A1, or U.S. Pat. No. 5,077,378 issued to Mueller et al. These materials, however, exhibit only moderate adhesion to substrates such as, for example, silicon oxide, silicon nitride, titanium nitride, tantalum nitride, glass or metals.
U.S. Pat. No. 3,644,288 issued to Odier et al. describes three-dimensionally crosslinked polybenzoxazoles obtained by cyclization from the corresponding crosslinked hydroxypolyamides by heating to a temperature in the range 220-400° C. The hydroxypolyamides are obtained by reacting an aromatic dihydroxydiamine compound, a dicarboxylic acid compound, and a tricarboxylic acid compound with one another. In one variant, the hydroxypolyamides are prepared by preparing in a first stage a linear polyamide of low molecular weight, starting from a dihydroxydiamine and a dicarboxylic acid compound, and in a second stage crosslinking this linear polyamide by adding a triester of a tricarboxylic acid. The hydroxypolyamides obtained in this way have a structure that is three-dimensionally crosslinked to a high degree and are therefore insoluble solids. For further processing, these solids are pulverized. Accordingly, it is very difficult if not impossible to process these hydroxypolyamides to thin coats, because they cannot be applied to a surface by spin coating in the form of a solution in an appropriate solvent, These hydroxypolyamides are therefore unsuited to application in microelectronics.
U.S. Pat. No. 3,644,286 issued to Odier et al. describes crosslinked polyamides and processes for preparing them. Appropriate dihydroxydiamines are reacted with dicarboxylic acid derivatives and tricarboxylic acid derivatives to give infusible solids that cannot be dissolved in organic solvents and sulphuric acid. Since these polyhydroxyamides cannot be applied in the form of a thin coat to a substrate, these compounds are likewise unsuited to application in microelectronics.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a material and additive for highly crosslinked chemically and thermally stable polyhydroxyamide polymers that overcome the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and that are readily soluble in organic solvents and, from which, it is possible to prepare polybenzoxazoles that have good insulating properties, high thermal and chemical stability, and good adhesion to all customary substrates.
This object is achieved by a polyhydroxyamide of the Formula I
where
a, a′, a″ to d, d′, d″ may each be identical or different and
a=0 or 1;
b=0 to 100;
c=0 or 1; and
d=0 or 1;
where
if a=0, b=c=0;
if c=0, d=0;
if d=1, e=1; and
if a =1 and b=c=0, d=0; and
where
Z
1
, Z
2
, and Z
3
, which may each be identical or different, denote a tetravalent radical having up to 100 carbon atoms;
Y
1
, Y
2
, and Y
3
, which may each be identical or different, denote a divalent radical containing at least two carbonyl groups which form an amide bond to the adjacent nitrogen, and comprising up to 100 carbon atoms; and
X, independently at each occurrence, denotes hydrogen or a monovalent radical having up to 30 carbon atoms which comprises at least one reactive group which is able to form a bond to another reaction center.
The polyhydroxyamides of the invention are readily soluble in many organic solvents, such as cyclohexanone, diethylene glycol monoethyl or diethyl ether, N-methylpyrrolidone, &ggr;-butryolactone or ethyl lactate. They can be processed readily, for example, by spin coating or by brush methods. After drying and baking on the substrate, during which the polyhydroxyamide is cyclized to the polyoxazole, the resulting film exhibits a substantially higher thermal stability than other comparable materials and a markedly better adhesion to a variety of substrates.
The polyhydroxyamides of the invention include as their central unit a radical derived from the benzenetricarboxylic acid. Going out from this central unit in a star formation are three linear side chains. In this form, the polyhydroxyamide of the Formula I does not yet exhibit a highly crosslinked form. However, because the side chains carry terminal groups X that can react with further compounds, the polyhydroxyamides of the Formula I are able to react with further polymers and crosslink them. Therefore, by adding polyhydroxyamides of the Formula I, highly-three-dimensionally crosslinked structures that possess high mechanical stability can be formed. By adding reactive groups X, containing for example a polymerizable double bond, the polyhydroxyamides of the Formula I may also be crosslinked further themselves. Accordingly, the polyhydroxyamides of the Formula I, accordingly can also be used themselves as a starting product for conversion into corresponding polybenzoxazoles. As a result of the branching of the polymers at the central unit derived from a benzenetricarboxylic acid, and/or, where appropriate, by further crosslinking, the polymer acquires a desirable high mechanical stability. The polyhydroxyamides of the Formula I may also, however, be used as crosslinking agents for other, preferably linear, polymers. Through the fraction of the added polyhydroxyamides of the Formula I, it is possible in this case to control the degree of crosslinking and consequently, for example, the solubility of the crosslinked polymer in an organic solvent as well. The central radical is preferably of symmetrical construction; in other words, it is derived from 1,3,5-benzenetricarboxylic acid. However, other substitution patterns of the central benzene nucleus may be realized. Attached to each of the three carbonyl groups of the central benzene radical, via an amide bond, is a side chain. The three side chains may be identical or different and may have different chain lengths. The conditions stated for the indices a to d therefore apply analogously to the indices a′ to d′ and, respectively, a″ to d″ as
Halik Marcus
Hösch Holger
Recai Sezi
Walter Andreas
Greenberg Laurence A.
Hampton Hightower P.
Infineon - Technologies AG
Locher Ralph E.
Stemer Werner E.
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