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:
Jan. 11, 1977
Filed:
Apr. 16, 1975
Ingrid E Magdo, Hopewell Junction, NY (US);
Steven Magdo, Hopewell Junction, NY (US);
IBM Corporation, Armonk, NY (US);
Abstract
In the fabrication of integrated circuits, a method is provided for forming masking structures comprising silicon nitride which avoids the stresses and dislocations associated with direct silicon nitride masking as well as the 'bird's beak' problems associated with silicon dioxide-silicon nitride composite mask structures. The mask is formed by first forming a silicon dioxide mask having at least one opening through which the substrate is exposed. Then, a mask comprising silicon nitride is formed on the first mask; this mask has at least one opening laterally smaller than the openings in the first mask and respectively in registration with at least some of the openings in said first mask. Thus, the second mask contacts and covers a portion of the exposed silicon substrate under each of the registered openings. The masked silicon substrate is subjected to a processing step such as oxidation, etching or diffusion which alters the characteristics of those portions of the silicon substrate remaining exposed. During this processing step a second mask serves as a barrier mask.