The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 02, 1985
Filed:
May. 03, 1984
Robert G Brault, Santa Monica, CA (US);
Hughes Aircraft Company, El Segundo, CA (US);
Abstract
Disclosed is a method of pretreating a semiconductor wafer so that a solution coating of a positive resist of poly(methacrylic anhydride) can be directly applied to the treated surface. A typical semiconductor wafer of silicon is first precoated with a thin layer of poly(t-butyl methacrylate) and then heated to convert the poly(t-butyl methacrylate) to the anhydride. The thickness of this anhydride-precursor layer is less than about 1,000 Angstroms. Next, there is applied to the surface of the precursor layer a solution of the poly(methacrylic anhydride) dissolved in, for example, dimethylacetamide, dimethylformamide, or N-methylprrolidione. Such solvents, which are not capable of adequately wetting the silicon surface directly, are capable of wetting the precursor layer comprising poly(methacrylic anhydride), thus ensuring a uniform deposit of poly(methacrylic anhydride) upon the treated surface of the wafer. After the solution has been applied to the treated wafer, the solvent is removed by evaporation to form a uniform solution-deposited poly(methacrylic anhydride) layer having a thickness which ranges from about 2,000 Angstroms to about 20,000 Angstroms.