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:
Dec. 05, 1995
Filed:
Dec. 21, 1994
Yoshimi Shiramizu, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
In a cleaning method, two kinds of cleaning solutions, one of which is acid solution of about pH 2 or less (first cleaning solution) and other of which is acid solution of about pH 3 to 4 (second cleaning solution), are successively used to clean a semiconductor substrate. In a first cleaning step, the semiconductor substrate is cleaned with the first cleaning solution to transform metals on the surface of the semiconductor substrate to metallic complex salts, and then in a second cleaning step the semiconductor substrate is cleaned with the second cleaning solution to transfer the metallic complex salts adsorbed on the surface of the semiconductor substrate into the second cleaning solution by osmotic pressure due to the difference in pH between the first and second cleaning solutions.