DEVICE FOR APPLYING MAGNETIC FIELD TO A FILTER FOR REDUCING METALLIC CONTAMINANTS

• US 20200129895A1
• Filed: 08/22/2019
• Published: 04/30/2020
• Est. Priority Date: 10/31/2018
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: MAI, Hsuan-Ying, LEE, Hui-Chun, CHEN, Chun-Kuang, FENG, Tung-Hung
• Granted Patent: US 11,666,838 B2
• Time in Patent Office: Days
• CPC Class Codes: B01D 29/15 arranged for inward flow filtration
• CPC Class Codes: B01D 29/902 containing fixed liquid displacement elements or cores
• CPC Class Codes: B01D 35/06 Filters making use of electricity or magnetism ultrafiltration, microfiltration B01D61/14; electrodialysis, electro-osmosis B01D61/42; devices comprising filters and magnetic separators B03C1/30
• CPC Class Codes: B01D 35/30 Filter housing constructions
• CPC Class Codes: B03C 1/0332 using permanent magnets
• CPC Class Codes: B03C 1/0335 using coils
• CPC Class Codes: B03C 1/288 disposed at the outer circumference of a recipient
• CPC Class Codes: B03C 1/30 Combinations with other devices, not otherwise provided for
• CPC Class Codes: B03C 2201/18 Magnetic separation whereby the particles are suspended in a liquid
• CPC Class Codes: B03C 2201/20 Magnetic separation whereby the particles to be separated are in solid form
• CPC Class Codes: B03C 2201/22 characterised by the magnetical field, special shape or generation

Abstract

A filter is used for removing metallic contaminants in a solvent used in microcircuit fabrication. The filter includes a filter housing including a filter membrane for filtering solvent including metallic contaminants, and a magnet arranged about the filter housing and configured to generate a magnetic field to attract the metallic contaminants prior to the metallic contaminants entering the filter membrane. The magnet is arranged such that the magnetic field of the magnet is greater in a periphery of the filter housing compared to a central portion of the filter housing.

Claims

1. A filter, comprising:

a filter housing including a filter membrane for filtering solvent including metallic contaminants; and

a magnet arranged about the filter housing and configured to generate a magnetic field to attract the metallic contaminants prior to the metallic contaminants entering the filter membrane.

2. The filter of claim 1, wherein the magnet is arranged such that the magnetic field of the magnet is greater in a periphery of the filter housing compared to a central portion of the filter housing.

3. The filter of claim 1, wherein the magnet includes neodymium.

4. The filter of claim 1, wherein

the magnet is a bar magnet and the filter housing is cylindrical,

a plurality of bar magnets are attached to the filter housing, and

circumferentially adjacent bar magnets have opposite polarity poles in contact with the filter housing and diametrically opposite bar magnets have poles of a same polarity in contact with the filter housing.

5. The filter of claim 1, wherein

the magnet includes a plurality of arc segments arranged about the filter housing,

radially inner surfaces of adjacent arc segments include opposite polarity poles, and

radially inner surfaces of diametrically opposite arc segments have same polarity poles.

6. The filter of claim 5, wherein the filter housing is cylindrical and the plurality of arc segments contact an outer surface of the filter housing.

7. The filter of claim 5, wherein a plurality of magnets are disposed about the filter.

8. The filter of claim 7, wherein the plurality of magnets contact an outer surface of the filter housing.

9. A method of developing an exposed photoresist, comprising:

providing a filter including a filter membrane and a magnet arranged about the filter;

introducing a photoresist developer including metallic contaminants in the filter;

filtering, using the magnet, the metallic contaminants from the photoresist developer prior to the metallic contaminants entering the filter membrane; and

applying the filtered photoresist developer to the exposed photoresist.

10. The method of claim 9, further comprising arranging the magnet such that a magnetic field generated by the magnet is greater in a periphery of the filter compared to a central portion of the filter.

11. The method of claim 9, wherein the magnet includes neodymium.

12. The method of claim 9, wherein the filter includes a cylindrical filter housing that encloses the filter membrane, and the magnet is a bar magnet, and the method further comprises:

contacting a plurality of bar magnets to the filter housing such that circumferentially adjacent bar magnets have opposite polarity poles in contact with the filter housing and diametrically opposite bar magnets have poles of a same polarity in contact with the filter housing.

13. The method of claim 9, wherein

the magnet includes a plurality of arc segments arranged about the filter,

adjacent arc segments have opposite polarity poles, and

diametrically opposite arc segments have same polarity poles.

14. The method of claim 13, wherein the filter includes a cylindrical filter housing enclosing the filter membrane and the method further includes contacting the magnet to an outer surface of the filter housing.

15. The method of claim 14, further comprising contacting a plurality of magnets to the outer surface of the filter housing.

16. A filter, comprising:

a filter membrane for filtering solvent including metallic contaminants; and

an annular magnet arranged about the filter to attract the metallic contaminants prior to the metallic contaminants entering the filter membrane, wherein the annular magnet is arranged such that a magnetic field generated by the annular magnet is greater in a periphery of the filter compared to a central portion of the filter.

17. The filter of claim 16, wherein the annular magnet includes neodymium.

18. The filter of claim 16, wherein

the annular magnet includes a plurality of magnetic arc segments arranged about the filter,

adjacent arc segments have opposite polarity poles, and

diametrically opposite arc segments have same polarity poles.

19. The filter of claim 18, wherein the filter includes a filter housing that encloses the filter membrane and the annular magnet contacts an outer surface of the filter housing,

20. The filter of claim 19, comprising a plurality of annular magnets contacting an outer surface of the filter housing.