Method for producing coating film-forming composition for lithography
US12153348B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 18, 2019 |
| Grant date | Nov 26, 2024 |
| Priority date | — |
| Expiry date | Nov 16, 2041 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D2239/1233
- WIPO fieldChemical engineering
- WIPO sectorChemistry
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.