Single-chamber sequential curing of semiconductor wafers

• US 8,137,465 B1
• Filed: 04/26/2005
• Issued: 03/20/2012
• Est. Priority Date: 04/26/2005
• Status: Active Grant

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Inventors: Wang, Feng, Kamian, George, Yam, Mark, Shrinivasan, Krishna, Gentile, Steve
• Primary Examiner(s): Zervigon, Rudy
• Application Number:
  US11/115,576
• Time in Patent Office: 2,520 Days
• Field of Search: 156/345.55, 156/345.31, 156/345.54, 118/719
• US Class Current: 118/719
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: H01L 21/67109 mainly by convection
• CPC Class Codes: H01L 21/67115 mainly by radiation

Abstract

The present invention relates to curing of semiconductor wafers. More particularly, the invention relates to cure chambers containing multiple cure stations, each featuring one or more UV light sources. The wafers are cured by sequential exposure to the light sources in each station. In some embodiments, the wafers remain stationary with respect to the light source during exposure. In other embodiments, there is relative movement between the light source and the wafer during exposure. The invention also provides chambers that may be used to independently modulate the cross-linking, density and increase in stress of a cured material by providing independent control of the wafer temperature and UV intensity.

Claims

1. An apparatus for curing a plurality of wafers, the apparatus comprising:

a) a chamber housing;

b) one or more wafer supports;

c) a plurality of non-overlapping UV exposure areas;

d) a plurality of UV light sources, each of which is associated with one and only one of the UV exposure areas, wherein each UV exposure area is illuminated by one and only one UV light source of the plurality of UV light sources; and

e) a rotational mechanism configured to;

1) sequentially expose each wafer to each of the plurality of UV light sources, wherein each wafer is uniquely within the associated UV exposure area during exposure to a particular UV light source,

2) concurrently expose multiple wafers to light from separate UV light sources, and

3) concurrently transfer multiple wafers between sequential UV exposure areas, wherein each of the concurrently transferred wafers is transferred from a different UV exposure area than from which any of the other concurrently transferred wafers are transferred, and wherein each of the concurrently transferred wafers is transferred to a different UV exposure area than to which any of the other concurrently transferred wafers are transferred.

2. The apparatus of claim 1, further comprising a mechanism for controlling the temperature of the wafer independent of the UV light intensity.

3. The apparatus of claim 1, wherein each UV light source includes a reflector block, the reflector block comprising at least one reflector configured to direct light emitted from the light source towards the associated UV exposure area.

4. The apparatus of claim 1, wherein each light source includes a cold mirror.

5. The apparatus of claim 4, wherein each cold mirror is mounted on a base coated with an IR-absorbing material.

6. The apparatus of claim 5, wherein each base includes coolant tubes.

7. The apparatus of claim 1, wherein the one or more wafer supports are configured to control the temperature of wafers supported by the one or more wafer supports.

8. The apparatus of claim 1, wherein the one or more wafer supports comprises a plurality of pedestals.

27. The apparatus of claim 1, wherein the rotational mechanism is centered among the plurality of UV exposure areas.

28. The apparatus of claim 1, wherein a relative orientation, as referenced to the rotational mechanism, between a first wafer support and a UV light source located directly above the first wafer support is different from a relative orientation, as referenced to the rotational mechanism, of a second wafer support and a UV light source located directly above the second wafer support, wherein the first and second wafer supports are different.

29. The apparatus of claim 1, further comprising a plurality of windows, each window associated with and disposed between a different UV light source and the associated UV exposure area, each window configured to prevent light emanated from the associated UV light source from illuminating the non-associated UV exposure areas.

30. The apparatus of claim 1, wherein each UV light source of the plurality of UV light sources includes a plurality of UV lamps.

31. The apparatus of claim 1, wherein:

the plurality of UV light sources includes a first UV light source with a first tubular lamp with a first illumination axis and a second UV light source with a second tubular lamp with a second illumination axis,

the plurality of UV exposure areas includes a first UV exposure area associated with the first UV light source and a second UV exposure area associated with the second UV light source,

the first illumination axis forms a first angle with respect to a first plane, the first plane coplanar with the rotational axis of the rotation mechanism and intersecting the center of the first UV exposure area,

the second illumination axis forms a second angle with respect to a second plane, the second plane coplanar with the rotational axis of the rotation mechanism and intersecting the center of the second UV exposure area, and

the first angle different from the second angle.

9. An apparatus for curing a plurality of wafers, the apparatus comprising:

a) a chamber housing;

b) one or more wafer supports;

c) a plurality of non-overlapping UV exposure areas;

d) a plurality of UV flood lamp sets, each UV flood lamp set associated with one and only one of the UV exposure areas, wherein each UV exposure area is illuminated by one and only one of the UV flood lamp sets; and

e) a rotational mechanism configured to;

1) sequentially expose each wafer separately to each of the plurality of UV flood lamp sets, wherein each wafer is uniquely within the associated UV exposure area during exposure to a particular UV flood lamp set and is stationary with respect to the particular UV flood lamp set during exposure;

2) concurrently expose multiple wafers to light from separate UV flood lamp sets, and

3) concurrently transfer multiple wafers between sequential UV exposure areas, wherein each of the concurrently transferred wafers is transferred from a different UV exposure area than from which any of the other concurrently transferred wafers are transferred, and wherein each of the concurrently transferred wafers is transferred to a different UV exposure area than to which any of the other concurrently transferred wafers are transferred.

10. The apparatus of claim 9, wherein the one or more wafer supports comprises a plurality of stationary pedestals and wherein the rotational mechanism comprises an indexer configured to move the wafers between the stationary pedestals.

11. The apparatus of claim 9, wherein the one or more wafer supports comprises a single stationary heating block and wherein the rotational mechanism comprises an indexer.

12. The apparatus of claim 9, wherein the one or more wafer supports comprises a carousel and the rotational mechanism comprises a mechanism to rotate the carousel.

13. The apparatus of claim 9, further comprising a stationary heating block.

14. The apparatus of claim 9, wherein each UV flood lamp set includes a reflector block, the reflector block comprising at least one reflector configured to direct light emitted from the UV flood lamp set towards the associated UV exposure area.

15. The apparatus of claim 9, wherein each UV flood lamp set is equipped with a parabolic cold mirror.

16. The apparatus of claim 15, wherein each cold mirror is mounted on a base coated with an IR-absorbing material.

17. The apparatus of claim 16, wherein each base includes coolant tubes.

18. The apparatus of claim 9, wherein the relative orientation between a first wafer support and a UV flood lamp set located directly above the first wafer support is different from the relative orientation of a second wafer support and a UV flood lamp set located directly above the second wafer support, wherein the first and second wafer supports are different.

19. An apparatus for curing a plurality of wafers, the apparatus comprising:

a) a chamber housing;

b) one or more wafer supports;

c) a plurality of non-overlapping UV exposure areas;

d) a plurality of UV focused lamp sets, each of which is associated with one and only one of the UV exposure areas, wherein each UV exposure area is illuminated by one and only one UV focused lamp set of the plurality of UV focused lamp sets; and

e) a rotational mechanism configured to;

1) sequentially expose each wafer to each of the UV focused lamp sets, wherein each wafer is uniquely within the associated UV exposure area during exposure to a particular UV focused lamp set and there is continuous relative movement between each wafer and the particular UV focused lamp set during exposure;

2) concurrently expose multiple wafers to light from separate UV focused lamp sets, and

3) concurrently transfer multiple wafers between sequential UV exposure areas, wherein each of the concurrently transferred wafers is transferred from a different UV exposure area than from which any of the other concurrently transferred wafers are transferred, and wherein each of the concurrently transferred wafers is transferred to a different UV exposure area than to which any of the other concurrently transferred wafers are transferred.

20. The apparatus of claim 19, wherein the one or more wafer supports comprises a carousel and the rotational mechanism is further configured to rotate the carousel.

21. The apparatus of claim 19, wherein the one or more wafer supports comprises a stationary heating block and wherein the wafers are suspended above the heating block.

22. The apparatus of claim 19, further comprising a reflector block;

wherein the reflector block comprises at least one reflector to reflect at least some of the light from a UV light source.

23. The apparatus of claim 19, wherein each UV lamp set is equipped with an elliptical cold mirror.

24. The apparatus of claim 23, wherein each cold mirror is mounted on a base coated with an IR-absorbing material.

25. The apparatus of claim 24, wherein each base includes coolant tubes.

26. The apparatus of claim 19, wherein the relative orientation between a first position and a lamp set located directly above the first position is different from the relative orientation of a second position and a lamp set located directly above the second position.

32. An apparatus for curing a plurality of wafers, the apparatus comprising:

a) a chamber housing;

b) one or more wafer supports;

c) a plurality of non-overlapping UV exposure areas;

d) a plurality of UV light sources, each of which is associated with one and only one of the UV exposure areas, wherein;

each UV exposure area is directly illuminated by the associated UV light source, and

each UV exposure area is not directly illuminated by any of the UV light sources associated with the other UV exposure areas; and

e) a rotational mechanism configured to;

1) sequentially expose each wafer to each of the plurality of UV light sources, wherein each wafer is uniquely within the associated UV exposure area during exposure to a particular UV light source,

2) concurrently expose multiple wafers to light from separate UV light sources, and

3) concurrently transfer multiple wafers between sequential UV exposure areas, wherein each of the concurrently transferred wafers is transferred from a different UV exposure area than from which any of the other concurrently transferred wafers are transferred, and wherein each of the concurrently transferred wafers is transferred to a different UV exposure area than to which any of the other concurrently transferred wafers are transferred.