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:
Jun. 05, 2012
Filed:
Jul. 22, 2008
Applicants:
Takanobu Takeda, Joetsu, JP;
Tamotsu Watanabe, Joetsu, JP;
Inventors:
Takanobu Takeda, Joetsu, JP;
Tamotsu Watanabe, Joetsu, JP;
Assignee:
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C08F 6/00 (2006.01);
U.S. Cl.
CPC ...
Abstract
A polymer for use in photoresist compositions is synthesized by effecting polymerization reaction to form a polymerization product mixture and subjecting the mixture to molecular weight fractionation by a liquid phase separation technique using a good solvent and a poor solvent. The fractionation step is iterated at least twice, and one iteration of fractionation includes adding a good solvent which is different from the good solvent added in the other iteration of fractionation.