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:
Feb. 13, 2001
Filed:
Aug. 27, 1997
Paul William Dryer, Gilbert, AZ (US);
Michael J. Davison, Mesa, AZ (US);
Ralph A. Dyrsten, Phoenix, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A wet etch bath (,) holds a wet etchant (,) for etching a dielectric over a semiconductor substrate. The wet etch bath (,) has a tub (,) separated from a reservoir (,) by a wall (,). The tub (,) is filled with the wet etchant (,) to a height of the wall (,). The reservoir (,) is filled with the wet etchant (,) to a height less than the height of the wall. A pump (,) coupled to the reservoir (,) pumps the wet etchant (,) through an osmotic membrane degasifier (,) to the tub (,). Adding the wet etchant (,) to the tub (,) causes the wet etchant (,) to cascade over the wall (,) back to the reservoir (,). The osmotic membrane degasifier (,) reduces a concentration of a reactive agent in the wet etchant (,).