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:
Aug. 17, 1999
Filed:
May. 19, 1998
Applicant:
Inventors:
Assignee:
Oki Electric Industry Co., Ltd., Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
H01L / ;
U.S. Cl.
CPC ...
438-3 ; 438253 ; 438240 ;
Abstract
In a process where a capacitor using a BST film for a dielectric film is incorporated into a DRAM, the film is selectively removed by wet etching for forming a contact hole. For this purpose, a bottom electrode is formed and then an amorphous film is formed on the entire surface of a silicon wafer. And after forming a crystalline top electrode on this film, lamp heating is performed to crystallize only the area that is in contact with the electrode. Then wet etching is performed using a solution of hydrogen and ammonium fluoride (1:2), which allows removing only the amorphous area selectively.