Method and apparatuses for reducing porogen accumulation from a UV-cure chamber

• US 9,073,100 B2
• Filed: 02/25/2013
• Issued: 07/07/2015
• Est. Priority Date: 12/05/2005
• Status: Active Grant

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Inventors: Gytri, Lisa, Gordon, Jeff, Lee, James, Balderrama, Carmen, Harris, Joseph Brett, Smargiassi, Eugene, Lau, Stephen Yu-Hong, Kamian, George D., Xi, Ming
• Primary Examiner(s): Lund, Jeffrie R
• Assistant Examiner(s): Antolin, Stanislav
• Application Number:
  US13/776,527
• Publication Number:
  US 20130284087A1
• Time in Patent Office: 862 Days
• Field of Search: 118/642, 118/723.VE, 118/724, 156/345.31, 156/345.33, 156/345.5, 156/345.54, 156/345.55, 392/416, 427/492, 427/508, 427/553, 427/595, 428/8, 438/378, 438/492, 438/795, 134/1, 134/166.R, 134/37
• US Class Current: 1/1
• CPC Class Codes: B08B 5/02 Cleaning by the force of jets, e.g. blowing-out cavities airguns or nozzles per se B05B1/005
• CPC Class Codes: B08B 7/00 Cleaning by methods not provided for in a single other subclass or a single group in this subclass
• CPC Class Codes: B08B 7/0035 by radiant energy, e.g. UV, laser, light beam or the like
• CPC Class Codes: B08B 7/0057 by ultraviolet radiation
• CPC Class Codes: B08B 7/0071 by heating B08B7/0035 takes precedence
• CPC Class Codes: H01L 21/02041 Cleaning
• CPC Class Codes: H01L 21/02203 the layer being porous
• CPC Class Codes: H01L 21/02348 treatment by exposure to UV light
• CPC Class Codes: H01L 21/223 using diffusion into or out of a solid from or into a gaseous phase H01L21/221 - H01L21/222 take precedence; diffusion through an applied layer H01L21/225
• CPC Class Codes: H01L 21/26 Bombardment with radiation H01L21/3105 takes precedence
• CPC Class Codes: H01L 21/67017 Apparatus for fluid treatment H01L21/67126, H01L21/6715 take precedence
• CPC Class Codes: H01L 21/67115 mainly by radiation

Abstract

Porogen accumulation in a UV-cure chamber is reduced by removing outgassed porogen through a heated outlet while purge gas is flowed across a window through which a wafer is exposed to UV light. A purge ring having specific major and minor exhaust to inlet area ratios may be partially made of flame polished quartz to improve flow dynamics. The reduction in porogen accumulation allows more wafers to be processed between chamber cleans, thus improving throughput and cost.

Claims

1. An apparatus comprising:

a UV light source;

a wafer support exposed to the UV light source;

a window having first and second sides, the window interposed between the UV light source and the wafer support such that the first side faces the UV light source and the second side faces the wafer support, wherein the wafer support is exposed to the UV light source through the window;

an inlet for injecting a purge gas; and

an outlet for exhausting the purge gas, wherein;

a portion of the inlet unbroken by the outlet spans 75% or more of a perimeter around the wafer support, and

the inlet and the outlet are both located such that the purge gas flows between the second side of the window and the wafer support.

2. The apparatus of claim 1, wherein the apparatus is a chamber comprising one or more stations and further comprises a heater configured to heat a portion of the chamber around the outlet.

3. The apparatus of claim 2, wherein the heater is configured to heat the portion of the chamber around the outlet to at least about 100°

C.

4. The apparatus of claim 2, wherein the portion of the chamber comprises a baffle.

5. The apparatus of claim 2, wherein the portion of the chamber includes chamber walls, a baffle, and an exhaust.

6. The apparatus of claim 1, wherein the outlet comprises flame polished quartz.

7. The apparatus of claim 1, wherein the outlet has a surface polish R_a of between about 4 and 63 angstroms.

8. The apparatus of claim 1, wherein the apparatus is a chamber comprising one or more stations and chamber materials surrounding the outlet are coated with a UV absorbing material.

9. An apparatus comprising:

a cure chamber having a window into the cure chamber;

a wafer support located in the cure chamber and configured to support a wafer; and

a purge ring positioned between the wafer support and the window, the purge ring having;

an inlet portion;

an inlet plenum located in the inlet portion, the inlet plenum being fluidly connectable to a gas source;

an inlet baffle located in the inlet portion;

an outlet portion;

a heater located in the outlet portion and configured to heat the outlet portion; and

an outlet channel located in the outlet portion, the outlet channel being located substantially opposite the inlet baffle across the purge ring, wherein;

the inlet portion and the outlet portion at least partially define a ring hole space,

the inlet baffle is operable to convey gas from the inlet plenum into the ring hole space,

the outlet portion is operable to convey gas and other matter out of the ring hole space, and

a portion of the inlet portion unbroken by the outlet portion spans more than 50% of a perimeter around the wafer support and a portion of the outlet portion unbroken by the inlet portion spans less than 50% of the ring hole space.

10. The apparatus of claim 9, wherein a major outlet area defined by a combined sectional surface area perpendicular to the wafer support plane of all features used for exhausting gases and a major inlet area defined by a combined inlet sectional surface area of all features that serve as final restrictions on the inlet path of a gas have a major outlet to major inlet surface area ratio that is greater than 4 for at least one station.

11. The apparatus of claim 10, wherein the ratio of the major outlet surface area to inlet surface area is greater than about 6 for at least one station.

12. The apparatus of claim 9, wherein a minor outlet surface area defined by a cross-sectional area of an opening of the outlet portion used to convey the gas and the other matter out of the ring hole space and a minor inlet surface area defined by a cross-sectional area of an opening of the inlet portion that is configured to convey purge gas supplied from the purge gas source to the inlet plenum have a minor outlet surface area to minor inlet surface area ratio that is greater than about 2.

13. A UV cure chamber, the chamber comprising one or more cure stations, each cure station comprising:

a. a window having a first side and a second side;

b. a UV light source mounted proximate to the first side of the window;

c. a wafer support exposed to the UV source disposed on the second side of the window, the wafer support providing a wafer support plane;

d. an inlet for injecting a purge gas, the inlet positioned on the wafer support side of the window and configured to direct the purge gas in a direction non-parallel to and toward the second side of the window; and

e. an outlet for exhausting the purge gas, the outlet positioned opposite the inlet on the wafer support side of the window, wherein;

a major outlet area is a combined sectional surface area perpendicular to the wafer support plane of all features used for exhausting gases,

a major inlet area is a combined inlet sectional surface area of all features that serve as final restrictions on the inlet path of a gas,

a ratio of the major outlet area to the major inlet area is greater than 4 for at least one of the one or more cure stations, and

a portion of the inlet unbroken by an outlet spans 75% or more of a perimeter around the wafer support.

14. The chamber of claim 13, wherein:

a minor outlet area is a cross sectional area of a primary gas exhaust opening connected to the outlet,

a minor inlet area is the cross sectional area of a primary gas delivery opening connected to the inlet, and

a ratio of the minor outlet area to the minor inlet area is greater than 2.

15. The chamber of claim 13, wherein at least one of the one or more cure stations further comprises a heater configured to heat chamber materials around the outlet.

16. The chamber of claim 15, wherein the heater is configured to heat chamber materials around the outlet to at least about 100°

C.

17. The chamber of claim 15, wherein the chamber materials comprise a baffle.

18. The chamber of claim 15, wherein the chamber materials include chamber walls, a baffle, and an exhaust.

19. The chamber of claim 13, wherein the outlet comprises flame polished quartz.

20. The chamber of claim 13, wherein the outlet has a surface polish Ra of between about 4 and 63 angstroms.

21. The chamber of claim 13, wherein the chamber materials surrounding the outlet are coated with a UV absorbing material.

22. The chamber of claim 13, wherein the chamber includes four cure stations and the outlet to inlet surface area ratio is greater than about 4 for three of the cure stations.

23. The chamber of claim 13, further comprising a heater configured to heat the outlet.