Method and apparatus for producing ultra-high purity water
The present invention relates to a system and method for producing ultrapure water, particular for use in immersion lithography processes. In one embodiment of the present invention, a self contained point-of-use cabinet that can consistently provide ultrapure water for use in immersion lithography equipment is provided. The present invention also relates to a system and method for providing a material having a predetermined specific refractive index to an immersion lithography device.
1 . A system for providing ultrapure water to a immersion lithography device, the system comprising:
a prefilter in fluid communication with a water supply;
a reverse osmosis unit in fluid communication with the prefilter;
a deionization unit in fluid communication with the reverse osmosis unit;
an ultraviolet light unit in fluid communication with the deionization unit;
a filter in fluid communication with the ultraviolet light unit;
a degasser in fluid communication with the filter; and
an ultrafilter in fluid communication with the degasser;
wherein ultrapure water exits the system from the ultrafilter and may be used by the immersion lithography device.
2 . A system according to claim 1 , wherein the system is housed in a single cabinet.
3 . A system according to claim 2 , wherein the cabinet is a point-of-use cabinet.
4 . A system according to claim 1 , further comprising:
a storage vessel in fluid communication with the reverse osmosis unit; and
a pump in fluid communication with the storage vessel and the deionization unit.
5 . A system according to claim 4 , wherein the system is housed in a single cabinet.
6 . A system according to claim 5 , wherein the cabinet is a point-of-use cabinet.
7 . A system according to claim 1 , wherein the deionization unit, the ultraviolet light unit, the filter, the degasser, and the ultrafilter are housed in a single cabinet.
8 . A system according to claim 7 , wherein the cabinet is a point-of-use cabinet.
9 . A system according to claim 1 , wherein the reverse osmosis unit and the ultrafilter are in fluid communication with a system drain.
10 . A system according to claim 4 , wherein the storage vessel is in fluid communication with a system drain.
11 . A system according to claim 1 , further comprising means to add dopants to the ultrapure water.
12 . A system according to claim 11 , wherein said means includes flow controllers.
13 . A system according to claim 12 , wherein said means further includes mixing means.
14 . A method of producing ultrapure water for an immersion lithography process, the method comprising:
treating a water supply by prefiltration to obtain prefiltered water;
treating the prefiltered water by reverse osmosis to remove ions and large molecules;
treating the water from the reverse osmosis process using ultraviolet light to remove impurities and suspend solids;
treating the water from the ultraviolet light process by filtration to obtain filtered water;
treating the filtered water by degassification to
treating the water from the degassification process to ultrafiltration to obtain ultrapure water.
15 . A method according to claim 14 , further comprising:
storing the water from the reverse osmosis process until requested for use by the immersion lithography process.
16 . A method according to claim 14 , further comprising:
adding a dopant to the ultrapure water.
17 . A system for providing a medium having a specific predetermined refractive index to an immersion lithography device, the system comprising:
a source of ultrapure water;
a source of at least one dopant material; and
means for combining the ultrapure water and the at least one dopant material to obtain the medium.
18 . A system according to claim 17 , wherein said means for combining includes a separate flow controller for the ultrapure water and for each of the at least one dopant material.
19 . A system according to claim 18 , wherein said means further includes mixing means.
20 . A method for providing a medium having a specific predetermined refractive index to an immersion lithography device, the method comprising:
providing a precise quantity of ultrapure water; and
adding a precise quantity of at least one dopant material to the ultrapure water to obtain the medium.
21 . A method according to claim 20 , wherein said adding is carried out using a separate flow controller for the ultrapure water and for each of the at least one dopant material.
22 . A system according to claim 20 , further comprising:
mixing the ultrapure water and the at least one dopant material.