Solvent prewet and method to dispense the solvent prewet
View Patent ↗A method and apparatus is provided for more efficient application of photoresist to a wafer surface. One aspect of the method comprises applying solvent to the wafer and spinning it to coat the entire wafer surface prior to the application of photoresist. This reduces surface tension on the wafer and reduces the amount of resist required to achieve a high quality film. The apparatus comprises adding a third solenoid and nozzle to the coating unit to accommodate the application of solvent to the center of the wafer surface. The method also describes incorporating a new solvent comprising diacetone alcohol, which is a low-pressure solvent, providing extended process latitudes and reduced material expenditures.
1. A method of coating a wafer, comprising:
dispensing a solvent on a wafer surface, wherein the solvent includes diacetone alcohol and aliphatic ester, wherein the diacetone alcohol is between 70% and 90% of the solvent;
spinning the wafer until the solvent is distributed across the wafer surface;
dispensing a photo resist solution on the wafer; and
spinning the wafer until the photo resist solution is distributed across the wafer surface.
2. The method of claim 1 , wherein dispensing a solvent comprises:
positioning a nozzle to dispense the solvent at a desired location on the wafer surface;
providing a solenoid to control the nozzle; and
actuating the solenoid to dispense the solvent.
3. The method of claim 1 , wherein the aliphatic ester is between 10% and 30% of the solvent.
4. A method of coating a wafer, comprising:
dispensing a solvent on a wafer surface, wherein the solvent includes diacetone alcohol and aliphatic ester, wherein the diacetone alcohol is approximately 70% of the solvent;
spinning the wafer until the solvent is distributed across the wafer surface;
dispensing a photo resist solution on the wafer; and
spinning the wafer until the photo resist solution is distributed across the wafer surface.
5. The method of claim 4 , wherein the aliphatic ester is between 10% and 30% of the solvent.
6. A method of coating a wafer, comprising:
dispensing a solvent on a wafer surface, wherein the solvent includes diacetone alcohol and aliphatic ester, wherein the diacetone alcohol is approximately 90% of the solvent;
spinning the wafer until the solvent is distributed across the wafer surface;
dispensing a photo resist solution on the wafer; and
spinning the wafer until the photo resist solution is distributed across the wafer surface.
7. A method of coating a wafer, comprising:
dispensing a solvent on a wafer surface, wherein the solvent includes diacetone alcohol and aliphatic ester, wherein the diacetone alcohol is between 70% and 90% of the solvent and the aliphatic ester is approximately 10% of the solvent;
spinning the wafer until the solvent is distributed across the wafer surface;
dispensing a photo resist solution on the wafer; and
spinning the wafer until the photo resist solution is distributed across the wafer surface.
8. A method of coating a wafer, comprising:
dispensing a solvent on a wafer surface, wherein the solvent includes diacetone alcohol and aliphatic ester, wherein the diacetone alcohol is approximately 70% of the solvent and the aliphatic ester is approximately 30% of the solvent;
spinning the wafer until the solvent is distributed across the wafer surface;
dispensing a photo resist solution on the wafer; and
spinning the wafer until the photo resist solution is distributed across the wafer surface.
9. A method of coating a wafer, comprising:
providing a wafer processing machine that includes a prewetting nozzle;
positioning a nozzle to dispense a solvent through the prewetting nozzle at a desired location on the wafer surface, wherein the solvent includes between 70% and 90% diacetone alcohol and further includes aliphatic ester;
actuating a solenoid to control solvent flow through the prewetting nozzle;
spinning the wafer until the solvent is distributed across the wafer surface;
dispensing a photo resist solution on the wafer, and
spinning the wafer until the photo resist solution is distributed across the wafer surface.
10. The method of claim 9 , wherein spinning the wafer until the solvent is distributed across the wafer surface includes spinning the wafer until the solvent is partially dry.
11. The method of claim 9 , wherein the aliphatic ester is between 10% and 30% of the solvent.
12. A method of coating a wafer, comprising:
distributing a solvent on a wafer surface, the solvent including aliphatic ester and 70% to 90% diacetone alcohol;
partially drying the wafer surface; and
distributing a photo resist solution on the wafer surface.
13. The method of claim 12 , wherein distributing a solvent comprises:
dispensing the solvent on the wafer surface; and
spinning the wafer until the solvent is distributed across the wafer surface.
14. The method of claim 12 , wherein partially drying the wafer surface comprises spinning the wafer until the wafer surface is partially dry.
15. The method of claim 12 , wherein distributing a photo resist solution comprises applying the photo resist solution on the wafer surface and spinning the wafer at a ramping rate to form a uniform photo resist film on the wafer surface.
16. The method of claim 12 , wherein the solvent includes between 10% and 30% ester.
17. A method of coating a wafer, comprising:
distributing a solvent on a wafer surface, the solvent including aliphatic ester and approximately 70% diacetone alcohol;
partially drying the wafer surface; and
distributing a photo resist solution on the wafer surface.
18. The method of claim 17 , wherein the aliphatic ester is between 10% and 30% of the solvent.
19. A method of coating a wafer, comprising:
distributing a solvent on a wafer surface, the solvent including aliphatic ester and approximately 90% diacetone alcohol;
partially drying the wafer surface; and
distributing a photo resist solution on the wafer surface.
20. A method of coating a wafer, comprising:
distributing a solvent on a wafer surface, the solvent including approximately 10% aliphatic ester and between 70% and 90% diacetone alcohol;
partially drying the wafer surface; and
distributing a photo resist solution on the wafer surface.
21. A method of coating a wafer, comprising:
distributing a solvent on a wafer surface, the solvent including approximately 30% aliphatic ester and approximately 70% diacetone alcohol;
partially drying the wafer surface; and
distributing a photo resist solution on the wafer surface.
22. A method of coating a wafer, comprising:
distributing a solvent on a wafer surface, the solvent including aliphatic ester and further including 70% to 90% diacetone alcohol;
partially drying the wafer surface; and
forming a photo resist film on the wafer surface.
23. The method of claim 22 , wherein forming a photo resist film comprises:
dispensing a photo resist solution onto the wafer; and
distributing the photo resist across the wafer surface by spinning the wafer.
24. The method of claim 22 , wherein distributing a solvent includes distributing a solvent that includes between 10% ester and 90% alcohol to 30% ester and 70% alcohol.
25. A method of forming a photo resist film on a wafer, comprising:
prewetting a wafer surface with a solvent that includes between 10% and 30% aliphatic ester and between 70% to 90% diacetone alcohol; and
forming a photo resist film on the wafer surface.
26. The method of claim 25 , further comprising partially drying the wafer surface after prewetting the wafer surface.
27. The method of claim 25 , wherein prewetting the wafer surface comprises:
dispensing the solvent on the wafer surface; and
spinning the wafer.
28. The method of claim 25 , wherein prewetting the wafer surface comprises:
dispensing the solvent on the wafer surface;
distributing the solvent across the wafer surface; and
partially drying the wafer surface.
29. The method of claim 25 , wherein forming a photo resist film comprises:
dispensing a photo resist solution onto the wafer; and
distributing the photo resist solution across the wafer surface by spinning the wafer.
30. A method of forming a photo resist film on a wafer, comprising:
dispensing solvent on a wafer surface, wherein the solvent include aliphatic ester and between 70% to 90% diacetone alcohol;
spinning the wafer to dispense the diacetone alcohol and to partially dry the wafer surface; and
forming a photo resist film on the wafer surface.
31. The method of claim 30 , wherein the aliphatic ester is between 10% and 30% of the solvent.
32. A method of forming a photo resist film on a wafer, comprising:
dispensing a solvent on a wafer surface, the solvent including aliphatic ester and between 70% to 90% diacetone alcohol;
distributing the solvent across the wafer surface by spinning the wafer;
dispensing a photo resist solution onto the wafer; and
distributing the photo resist solution across the wafer surface by spinning the wafer.
33. The method of claim 32 , wherein dispensing a solvent on a wafer surface includes positioning a prewetting nozzle such that the solvent is dispensed at a desired location on the wafer surface.
34. The method of claim 32 , wherein dispensing a photo resist solution on the wafer includes dispensing a solvent component that includes a mixture of aliphatic ester and diacetone alcohol.
35. The method of claim 34 , wherein the solvent includes between 10% and 30% ester.
36. The method of claim 32 , wherein dispensing a photo resist solution on the wafer includes positioning a nozzle such that the photo resist solution is dispensed at a desired location on the wafer surface.
37. The method of claim 32 , wherein distributing the photo resist solution across the wafer surface by spinning the wafer includes spinning the wafer at a ramping rate to form a uniform photo resist film on the wafer surface.
38. The method of claim 32 , wherein dispensing diacetone alcohol on a wafer surface and dispensing a photo resist solution on the wafer both include dispensing the same solvent that is used to clean wafer edge after the photo resist solution has been distributed.
39. A method of coating a wafer, comprising:
providing a solvent, including between 10% aliphatic ester and 90% diacetone alcohol to 30% aliphatic ester and 70% diacetone alcohol;
distributing the solvent on a wafer surface as a solvent prewet; and
distributing the solvent as part of a photo resist solution on the wafer surface,
wherein distributing the solvent on a wafer surface as a solvent prewet includes dispensing the solvent on the wafer surface, and spinning the wafer.
40. A method of coating a wafer, comprising:
providing a solvent, including between 10% aliphatic ester and 90% diacetone alcohol to 30% aliphatic ester and 70% diacetone alcohol;
distributing the solvent on a wafer surface as a solvent prewet; and
distributing the solvent as Part of a photo resist solution on the wafer surface, wherein distributing the solvent on a wafer surface as a solvent prewet includes dispensing the solvent on the wafer surface, distributing the solvent across the wafer surface, and partially drying the wafer surface.
41. A method of coating a wafer, comprising:
providing a solvent, including between 10% aliphatic ester and 90% diacetone alcohol to 30% aliphatic ester and 70% diacetone alcohol;
distributing the solvent on a wafer surface as a solvent prewet; and
distributing the solvent as part of a photo resist solution on the wafer surface, wherein distributing the solvent as part of a photo resist solution on the wafer surface includes dispensing the photo resist solution on the wafer and spinning the wafer to distribute the photo resist solution across the wafer surface.
42. A method of coating a wafer, comprising:
selecting a solvent including between 70% to 90% diacetone alcohol and aliphatic ester;
dispensing the solvent on the wafer as a pre-wet step;
spinning the wafer until the solvent is distributed across the wafer surface;
dispensing a photoresist solution on the wafer having solvent on its surface; and
spinning the wafer until the photoresist is distributed across the wafer surface.
43. The method of claim 42 , wherein dispensing the solvent comprises:
positioning a nozzle to dispense the solvent in the middle of the wafer;
controlling the nozzle with a solenoid; and
causing the nozzle to dispense the solvent by signaling the solenoid.
44. The method of claim 42 , wherein the solvent includes between 70% and 90% aliphatic ester.
45. A method of coating a wafer, comprising:
directing a nozzle at a center of a wafer held in a wafer processing machine;
dispensing less than 1.0 cc of a solvent through the nozzle on the wafer as a pre-wet step, the solvent including aliphatic ester and between 70% and 90% diacetone alcohol;
spinning the wafer until the solvent is distributed across the wafer surface;
dispensing a photoresist solution on the wafer having solvent on its surface; and
spinning the wafer until the photoresist is distributed across the wafer surface.
46. The method of claim 45 , wherein the solvent includes between 70% and 90% aliphatic ester.
47. A method of coating a wafer, comprising:
positioning a nozzle such that it is directed at the center of a wafer;
controlling the nozzle with a solenoid;
causing the nozzle to dispense less than 1.0 cc of a solvent on the wafer as a pre-wet step by signaling the solenoid, the solvent including aliphatic ester and between 70% and 90% diacetone alcohol;
spinning the wafer until the solvent is distributed across the wafer surface;
dispensing a photoresist solution on the wafer before the solvent on the wafer surface is dry; and
spinning the wafer until the photoresist is distributed across the wafer surface.
48. The method of claim 47 , wherein the solvent includes between 70% and 90% aliphatic ester.