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. 16, 2001
Filed:
Aug. 26, 1998
Vikram N. Doshi, Plano, TX (US);
Hiro Tomomatsu, Plano, TX (US);
Roy D. Clark, Princeton, TX (US);
Richard L. Guldi, Dallas, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
Hydrofluoric acid (HF) mixed with water and often buffered with ammonium fluoride is a standard silicon dioxide wet etchant which is followed by a rinse. An improved silicon dioxide etch is vapor HF which may be followed by a water vapor rinse. The invention discloses a further improved silicon dioxide etch. Following an initial exposure to vapor HF for oxide removal, a first insitu water rinse occurs. A second exposure to vapor HF then occurs and is followed by a second insitu water rinse. Water, rather than water vapor, aids in freeing particles from the wafer surface. During both the water rinses, the wafer may be rotated at increasing speeds to aid in sweeping particles from wafer surface. The process may be practiced in a commercially available reactor and is suitable for ULSI devices having complex topographies, such as, for example, 64 megabit DRAMs employing crown type memory cells.