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:
Nov. 26, 2024
Filed:
Dec. 18, 2019
Nissan Chemical Corporation, Tokyo, JP;
NISSAN CHEMICAL CORPORATION, Tokyo, JP;
Abstract
A method for producing a coating film-forming composition for lithography, including a step for passing a liquid through a filter cartridge. The filter cartridge is obtained by layering more than one type of filtration base fabrics or winding same around a hollow inner tube, wherein: the fabrics are non-woven fabrics in which metal-adsorbing groups are chemically bonded to polyolefin fibers; the fabrics contain non-woven fabric layers A and B; layer A is configured from polyolefin fibers to which sulfonic acid groups are chemically bonded as metal-adsorbing groups; and layer B is configured from polyolefin fibers to which at least one type selected from among amino groups, N-methyl-D-glucamine groups, iminodiacetic acid groups, iminodiethanol groups, amidoxime groups, phosphoric acid groups, carboxylic acid groups and ethylenediamine triacetic acid groups chemically bonded as metal-adsorbing groups. Thus, the amount of metal impurities that are the cause of minute defects on a wafer can be reduced.