US 12,463,027 B2
Fine filters and methods for making the same
Tomoka Ogura, Tokyo (JP); and Hidesato Mano, Tokyo (JP)
Assigned to W. L. Gore & Associates G.K., Tokyo (JP)
Filed by W. L. Gore & Associates G.K., Tokyo (JP)
Filed on Aug. 24, 2022, as Appl. No. 17/894,665.
Application 17/894,665 is a division of application No. 15/741,994, granted, now 11,452,972, previously published as PCT/JP2016/072997, filed on Aug. 4, 2016.
Claims priority of application No. 2015-154539 (JP), filed on Aug. 4, 2015.
Prior Publication US 2022/0401888 A1, Dec. 22, 2022
Int. Cl. H01L 21/02 (2006.01); B01D 69/02 (2006.01); B01D 69/12 (2006.01); B01D 71/36 (2006.01); H01L 21/304 (2006.01); H05K 3/00 (2006.01); H05K 3/06 (2006.01); B01D 71/76 (2006.01)
CPC H01L 21/02 (2013.01) [B01D 69/02 (2013.01); B01D 69/1213 (2022.08); B01D 71/36 (2013.01); H01L 21/304 (2013.01); H05K 3/06 (2013.01); B01D 71/76 (2013.01); B01D 2325/16 (2013.01); H05K 3/0085 (2013.01)] 43 Claims
OG exemplary drawing
 
23. A method comprising:
obtaining a filter prepared by:
obtaining tetrafluoroethylene (F2C═CF2);
obtaining a fluoroolefin represented by a general formula: F2C═CF—R;
copolymerizing the tetrafluoroethylene with the fluoroolefin to form a tetrafluoroethylene copolymer having a side chain comprising a functional group R;
wherein the tetrafluoroethylene copolymer comprises at least one portion of the filter; and
modifying the tetrafluoroethylene copolymer with a linker group resulting in a modified side chain comprising an amino group, wherein a ratio of the amino group to the tetrafluoroethylene copolymer is from 0.1 μmol/g to 10 mmol/g;
obtaining a circuit board process liquid; and
filtering the circuit board process liquid using the filter, so as to remove particles from the circuit board process liquid;
wherein the filter comprises a tetrafluoroethylene copolymer;
wherein the tetrafluoroethylene copolymer comprises an amino group in a side chain.