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. 11, 1992
Filed:
Aug. 05, 1991
Applicant:
Inventor:
Johnny C Chen, San Jose, CA (US);
Assignee:
Read-Rite Corp., Milpitas, CA (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C25D / ;
U.S. Cl.
CPC ...
205135 ; 2041922 ; 20419222 ;
Abstract
A process for making thin film magnetic heads includes forming a precisely defined back gap opening used for magnetic closure of the P1 and P1 pole pieces. A mushroom-like photoresist structure having a cap layer supported by a stem layer is formed over the P1 pole piece by a double resist spin and double exposure method with a critical baking step to harden previously deposited photoresist layers between the first exposure and the second photoresist spin. The cap layer defines the back gap opening. When the mushroom-like photoresist structure is removed by a single step lift-off with a solvent, the back gap opening is formed.