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:
Oct. 31, 2000
Filed:
Dec. 18, 1998
George R Misium, Plano, TX (US);
Sunil V Hattangady, McKinney, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A method is disclosed of nitridating an oxide layer (12) to form a stop layer for selective etching of sacrificial layer comprising the steps of, obtaining a wafer (10), forming a gate (30) on the wafer (10), depositing an oxide layer (12) on the wafer (10) and the gate (30), exposing the surface of the oxide layer (12) to a nitrogen ion containing plasma at, e.g., room temperature, wherein the nitrogen ions form a nitrided layer (22) on the oxide layer (12). Next, a silicate layer (32) is deposited on the nitrided layer (22), planarized and patterned with photoresist (14) for etching. The contacts or vias are then formed through the silicate layer (32) by etching down to the nitrided layer (22) that acts as a stop layer, followed by a second etching step that removes the nitrided layer (22). The photoresist (14) is then stripped and the silicon oxide layer (12) etch down to the wafer (10). The process of the present invention prevents the exposure of the wafer (10) to contaminants from the photoresist layer (14) and the etch chemicals that can deposit reactive radicals. These reactive radicals, also known as mobile ions, decrease the reliability of the device by contaminating subsequent layers or structures.