Reflective surface for CVD reactor walls

• US 6,319,556 B1
• Filed: 11/09/1999
• Issued: 11/20/2001
• Est. Priority Date: 07/11/1997
• Status: Expired due to Term

• Current Assignee: ASM America Incorporated (ASM International NV)
• Original Assignee: Micron Technology, Inc.
• Inventors: Olsen, Aage, Halpin, Michael W.
• Primary Examiner(s): Wong, Edna
• Application Number:
  US09/437,069
• Time in Patent Office: 742 Days
• Field of Search: 427/307, 427/299, 427/180, 427/184, 205/206, 205/208
• US Class Current: 427/307
• CPC Class Codes: C23C 14/12 Organic material
• CPC Class Codes: C23C 14/28 by wave energy or particle radiation C23C14/32 - C23C14/48 take precedence
• CPC Class Codes: C23C 16/481 by radiant heating of the substrate
• CPC Class Codes: C30B 25/105 by irradiation or electric discharge
• CPC Class Codes: C30B 31/12 Heating of the reaction chamber
• CPC Class Codes: G02B 5/0215 the surface having a regular structure
• CPC Class Codes: G02B 5/0221 the surface having an irregular structure G02B5/0226 takes precedence
• CPC Class Codes: G02B 5/0268 characterized by the fabrication or manufacturing method
• CPC Class Codes: G02B 5/0284 used in reflection

Abstract

A reflector plate is provided for scattering radiant heat energy in a semiconductor processing reactor chamber to achieve uniform temperature across a substrate to be processed. The surface is characterized by a plurality of adjoining depressions with substantially no planar sections among the depressions. The width to depth ratio for the depressions averages over 3:1. Crests separating the depressions define an angle of greater than about 60°, thus providing a relatively smooth texture for the reflecting surface. The reflecting surface is thus easy to clean. A method of manufacturing the reflector plate comprises removing material from a planar metal surface by ball-end milling. The depth of each depression and degree of overlap with adjacent depressions can randomly vary within selected ranges. A highly specular finish is then provided on the stippled surface by gold electroplating.

Claims

1. A method of manufacturing a reflector for scattering radiant energy in a semiconductor processing tool, comprising:

providing a base plate with a substantially planar surface;

removing material from substantially all of the planar surface in a region of the base plate to produce a non-planar surface, wherein removing material comprises milling a plurality of cavities in the planar surface;

providing a reflecting finish on the non-planar surface; and

placing the base plate in the semiconductor processing tool.

2. The method of claim 1, wherein removing material from substantially all of the planar surface comprises removing greater than about 98% of the planar surface in the region.

3. The method of claim 2, wherein removing material from substantially all of the planar surface comprises removing greater than about 99% of the planar surface in the region.

4. The method of claim 1, wherein milling the plurality of cavities comprises:

milling a first cavity to a first randomly selected depth within a predetermined range of depths;

moving the base plate relative to a mill by a randomly selected distance within a predetermined range of distances; and

milling a second cavity to a second randomly selected depth within the predetermined range of depths.

5. The method of claim 1, wherein the cavities overlap over substantially all of the base plate non-planar surface.

6. The method of claim 1, wherein the cavities have a width to depth ratio greater than about 5:

1.

7. The method of claim 1, wherein milling the cavities comprises applying a ball-end mill to the planar surface.

8. The method of claim 7, wherein the ball-end mill has a diameter between about {fraction (1/16)} inch and ½

inch.

9. The method of claim 8, wherein the ball-end mill has a diameter of about ⅜

inch.

10. The method of claim 8, wherein milling the cavities comprises removing material to a depth of between about 0.0005 inch and 0.02 inches.

11. The method of claim 8, wherein milling the cavities comprises removing material to a depth of between about 0.008 inch and 0.012 inch.

12. The method of claim 1, wherein the non-planar surface includes substantially no planar surfaces.

13. The method of claim 1, wherein providing the reflecting finish comprises providing a specular finish on the non-planar surface.

14. The method of claim 1,wherein providing the specular finish comprises nickel flash plating the non-planar surface prior to gold electroplating.

15. A method of manufacturing a reflector plate for scattering radiant energy in a high temperature semiconductor processing reactor, comprising:

providing a base plate with a substantially planar surface;

forming a plurality of depressions in the base plate, each of the depressions having a depth into the base plate and a width in a dimension perpendicular to the depth, a ratio of width to depth for the depressions across the base plate averaging greater than about 3;

1;

providing a specular finish on the depressions, to form a reflector plate; and

positioning the reflector plate within the high temperature semiconductor processing reactor.

16. The method of claim 15, wherein the ratio of width to depth for the depressions across the base plate averages greater than about 5:

1.

17. The method of claim 16, wherein the ratio of width to depth for the depressions across the base plate averages greater than about 10:

1.

18. The method of claim 15, wherein forming the plurality of depressions comprises removig material from the planar surface of the base plate.

19. The method of claim 15, wherein forming the plurality of depressions comprises milling a plurality of overlapping cavities.

20. The method of claim 19, wherein milling the plurality of overlapping cavities comprises milling each cavity to a randomly chosen depth within a predetermined range of depths.