Fine filters and methods for making the same

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.

A method for producing a circuit board, comprising:

• forming one or more selected from the group consisting of a circuit, a semiconductor device and a semiconductor device precursor on a circuit board by using a process liquid for a circuit board production;
• wherein the process liquid for the circuit board production is filtered by a device comprising:
• 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.