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US4595775A
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N-methylhydridosilazanes, polymers thereof, methods of making same and silicon nitrides produced therefrom
Assignee: Petrarch Systems Inc
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Filing: 1984-04-06
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Granted: 1986-06-17
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Expires: 2004-04-06
Abstract
Abstract Cyclic silazanes which are particularly useful for the formation of silicon nitrides have the general formula: ##STR1## wherein Me represents methyl (CH 3 ), n=3-6, x=0-1 and y=0.25-1. These N-methylhydridosilazanes are a convenient source of silicon nitride by chemical vapor deposition to form films for masking layers and dielectric coatings with reduced levels of silicon carbide contamination in the silicon nitride. Low molecular weight, linear polymers of the N-methylhydridosilazanes are also useful in the preparation of silicon nitrides by evaporation from liquid solutions and subsequent pyrolysis and are particularly useful for infiltration of refractories. Particularly preferred compounds of the invention are 2,6 di-N-methyl-1,3,5,7-tetramethylcyclotetrasilazane; 2,4,6,8-tetra-N-methyl-1,5-dimethylcyclotetrasilazane and their polymeric derivatives.
Inventors
- 👤 Barry C. Arkles
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:30
CPC Classifications
C; C07; C07F; C07F7/00; C07F7/02; C07F7/21
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
18 words
A cyclic silazane of the formula: ##STR7## wherein Me represents methyl (CH 3 ), n=3-6, x=0-1 and y=0.25-1.
Claim 2
Dependent Claim
18 words
A cyclic silazane of the formula: ##STR7## wherein Me represents methyl (CH 3 ), n=3-6, x=0-1 and y=0.25-1.
Claim 3
Dependent Claim
9 words
A cyclic silazane according to claim 1 wherein n=3.
Claim 4
Dependent Claim
9 words
A cyclic silazane according to claim 1 wherein n=4.
Claim 5
Dependent Claim
3 words
2,6 di-N-methyl-1,3,5,7 tetramethylcyclotetrasilazane.
Claim 6
Dependent Claim
3 words
2,6 di-N-methyl-1,3,5,7 tetramethylcyclotetrasilazane.
Claim 7
Dependent Claim
3 words
2,4,6,8 tetra-N-methyl-1,5 dimethylcyclotetrasilazane.
Claim 8
Dependent Claim
3 words
2,4,6,8 tetra-N-methyl-1,5 dimethylcyclotetrasilazane.
Claim 9
Dependent Claim
3 words
2,4,6 tri-N-methyl-1,3,5 trimethylcyclotrisilazane.
Claim 10
Dependent Claim
3 words
2,4,6 tri-N-methyl-1,3,5 trimethylcyclotrisilazane.
Claim 11
Dependent Claim
20 words
Polymeric derivatives of the cyclic silazanes of claim 1 produced by equilibration of said cyclic silazanes with an ammonium salt.
Claim 12
Dependent Claim
62 words
A method of producing the cyclic silazane of claim 4 and polymeric derivatives thereof comprising reacting methyldichlorosilane with methylamine in the presence of a basic receptor and a hydrocarbon solvent under chilled conditions, adding ammonia to the reaction mixture, filtering out amine hydrochlorides, stripping the solvent from the mixture and distilling the remainder to yield said cyclic silazane and polymeric derivatives thereof.
Claim 13
Dependent Claim
62 words
A method of producing the cyclic silazane of claim 5 and polymeric derivatives thereof comprising reacting methyldichlorosilane with methylamine in the presence of a basic receptor and a hydrocarbon solvent under chilled conditions, adding dichlorosilane to the reaction mixture, filtering out amine hydrochlorides, stripping the solvent from the mixture and distilling the remainder to yield said cyclic silazane and polymeric derivatives thereof.
Claim 14
Independent Claim
19 words
A method according to claims 8 or 9 wherein said basic receptor is triethylamine and said solvent is pentane.
Claim 15
Dependent Claim
14 words
Polymeric derivatives produced as a byproduct of the methods of claims 8 or 9.
Claim 16
Dependent Claim
5 words
Poly 2,6 di-N-methyl- 1,3,5,7 tetramethylcyclotetrasilazane.
Claim 17
Dependent Claim
5 words
Poly 2,6 di-N-methyl- 1,3,5,7 tetramethylcyclotetrasilazane.
Claim 18
Dependent Claim
4 words
Poly 2,4,6,8 tetra-N-methyl-1,5 dimethylcyclotetrasilazane.
Claim 19
Dependent Claim
4 words
Poly 2,4,6,8 tetra-N-methyl-1,5 dimethylcyclotetrasilazane.
Claim 20
Dependent Claim
4 words
Poly 2,4,6 tri-N-methyl-1,3,5 trimethylcyclotrisilazane.
Claim 21
Dependent Claim
4 words
Poly 2,4,6 tri-N-methyl-1,3,5 trimethylcyclotrisilazane.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-06-16 | 1989-12-16 | 1990-06-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-06-16 | 1993-12-16 | 1994-06-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-06-16 | 1997-12-16 | 1998-06-17 | $7700.00 | Window Closed / Lapsed |