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:
Mar. 24, 1992
Filed:
Jun. 18, 1991
Klaus D Beyer, Poughkeepsie, NY (US);
Louis L Hsu, Fishkill, NY (US);
Subodh K Kulkarni, Fishkill, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A process for forming air-filled isolation trenches in a semiconductor substrate by a conformal chemical vapor deposition (CVD) of a silicon dioxide layer over the passivated surface of the semiconductor substrate in which intersecting trenches have been formed and partially filled with a material that can subsequentially be removed from under the CVD silicon dioxide layer, such materials include water soluble glasses and polymeric materials, such as a polyimide. The CVD silicon dioxide is etched back to the passivated surface of the semiconductor substrate, forming openings in the layer at the trench intersections that extend to the trench fill material. The fill material is removed through these openings. A CVD silicon dioxide layer is deposited to fill the openings, leaving a silicon dioxide cap bridging the air-filled trench. Water soluble glasses that may be used to fill the trench include BSG glass (B.sub.2 O.sub.3 content greater than 55%) and germanosilicate glass (GeO.sub.2 content greater than 50%). A polymer fill, such as a polyimide, if used, may be removed by plasma etching in O.sub.2.