| CPC B01D 61/58 (2013.01) [B01D 3/145 (2013.01); B01D 61/145 (2013.01); B01D 61/147 (2013.01); B01D 61/18 (2013.01); B01D 65/02 (2013.01); B01D 69/02 (2013.01); B01D 69/08 (2013.01); B01D 69/1213 (2022.08); B01D 71/36 (2013.01); C08F 236/20 (2013.01); C08J 9/365 (2013.01); H01L 21/67017 (2013.01); B01D 2311/2523 (2022.08); B01D 2311/2623 (2013.01); B01D 2311/2669 (2013.01); B01D 2317/02 (2013.01); B01D 2325/022 (2013.01); B01D 2325/36 (2013.01); B01D 2325/42 (2013.01); C08J 2327/18 (2013.01); C08J 2347/00 (2013.01); G03F 7/32 (2013.01); G03F 7/422 (2013.01)] | 14 Claims |

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1. A filtering device for obtaining a chemical liquid by purifying a liquid to be purified, comprising:
an inlet portion;
an outlet portion;
a filter A;
at least one filter B different from the filter A; and
a flow path extending from the inlet portion to the outlet portion,
wherein the filter A and the filter B are arranged in series between the inlet portion and the outlet portion,
the filter A is a filter A1,
the filter A1 has a porous base material made of polytetrafluoroethylene and a coating layer which is disposed to cover the porous base material and contains a fluorinated ionomer,
the fluorinated ionomer contains
a fluorinated monomer unit containing an ethylene group and a functional group which is convertible into a hydrophilic group selected from the group consisting of —SO2F, —COOR, —COF, and a combination of these, R is a C1-C20 alkyl radical or a C6-C20 aryl radical;
a monomer unit derived from at least one bis-olefin selected from the group consisting of Formulas (OF-1), (OF-2), and (OF-3); and
at least one kind of atom selected from the group consisting of an iodine atom and a bromine atom,
![]() in Formula (OF-1), j is an integer of 2 to 10, and R1, R2, R3, and R4 may be the same as or different from each other and each represent H, F, or a C1-C5 alkyl group, a perfluoroalkyl group, or a fluoroalkyl group,
![]() in Formula (OF-2), a plurality of A's may be the same as or different from each other and are each independently selected from the group consisting of F, Cl, and H, a plurality of B's may be the same as or different from each other and are each independently selected from the group consisting of F, Cl, H, and ORB, RB is a branched or linear alkyl radical capable of being at least partially fluorinated or chlorinated, E is a divalent group which is capable of being inserted into an ether bond, is fluorinated as necessary, and has 2 to 10 carbon atoms,
![]() in Formula (OF-3), E, A, and B have the same definition as E, A, and B in Formula (OF-2), R5, R6, and R7 may be the same as or different from each other and each represent H, F, a C1-C5 alkyl group, a perfluoroalkyl group, or a fluoroalkyl group,
wherein the chemical liquid is a resist solution,
the filter B includes at least a filter BD disposed on a downstream side of the filter A on the flow path,
the filter BD contains polyolefin,
the filter B includes at least one filter BU disposed on an upstream side of the filter A on the flow path,
the at least one filter BU has a pore size equal to or greater than 50 nm and, the pore size of the at least one filter BU is equal to or smaller than 200 nm.
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