Support apparatus for semiconductor wafer processing

• US 6,576,064 B2
• Filed: 07/10/1997
• Issued: 06/10/2003
• Est. Priority Date: 07/10/1997
• Status: Expired due to Term

• Current Assignee: National Technology & Engineering Solutions Of Sandia LLC (Honeywell International Inc.)
• Original Assignee: Sandia Corporation (Martin Marietta Corporation)
• Inventors: Torres, Kenneth J., Nilson, Robert H., Griffiths, Stewart K.
• Primary Examiner(s): LUND, JEFFRIE ROBERT
• Application Number:
  US08/891,304
• Publication Number:
  US 20010001953A1
• Time in Patent Office: 2,161 Days
• Field of Search: 118/728, 118/715, 118/729, 118/725, 118/500, 118/502, 432/249, 432/241
• US Class Current: 118/728
• CPC Class Codes: C23C 16/4583 the substrate being supported substantially horizontally
• CPC Class Codes: H01L 21/6875 characterised by a plurality of individual support members, e.g. support posts or protrusions
• CPC Class Codes: H01L 21/68757 characterised by a coating or a hardness or a material

Abstract

A support apparatus for minimizing gravitational stress in semiconductor wafers, and particularly silicon wafers, during thermal processing. The support apparatus comprises two concentric circular support structures disposed on a common support fixture. The two concentric circular support structures, located generally at between 10 and 70% and 70 and 100% and preferably at 35 and 82.3% of the semiconductor wafer radius, can be either solid rings or a plurality of spaced support points spaced apart from each other in a substantially uniform manner. Further, the support structures can have segments removed to facilitate wafer loading and unloading. In order to withstand the elevated temperatures encountered during semiconductor wafer processing, the support apparatus, including the concentric circular support structures and support fixture can be fabricated from refractory materials, such as silicon carbide, quartz and graphite. The claimed wafer support apparatus can be readily adapted for use in either batch or single-wafer processors.

Claims

1. An apparatus for supporting a surface of a semiconductor wafer during thermal processing, comprising:

a support fixture comprising a plate-like member; and

a wafer support means consisting of first and second arrays of uniformly spaced projecting points having substantially the same height above said plate-like member, wherein said first and second arrays of projecting points are disposed on said support fixture at respective first and second concentric diameters, wherein said first diameter is equal to about 10% to 70% of a diameter of the semiconductor wafer and said second diameter is equal to about 70% to 100% of the semiconductor wafer diameter, said support fixture and said wafer support means selected from the group of materials consisting of quartz, silicon carbide and graphite.

2. The apparatus of claim 1, wherein said first diameter is about equal to 35.0% of the semiconductor wafer diameter and wherein said second diameter is about equal to 82.3% of the semiconductor wafer diameter.

3. The apparatus of claim 1, wherein some of said uniformly spaced projecting points in said first and said second arrays of projecting points have been removed to permit access for a semiconductor wafer loading and unloading means.

4. A vertical carrier means for supporting a surface of each of a plurality of semiconductor wafers during thermal processing, comprising:

a plurality of support fixtures extending between a top end and a bottom end of said carrier means and spaced in a substantially uniform manner between said top and bottom ends;

wherein each support fixture comprises a plate-like member; and

wafer support means disposed on each of said plurality of support fixtures, wherein each of said wafer support means consists of first and second arrays of uniformly spaced projecting points having substantially the same height above said plate-like member, wherein said first and second arrays of projecting points are disposed on said support fixture at respective first and second concentric diameters, wherein said first diameter is equal to about 10% to 70% of a diameter of the semiconductor wafer and said second diameter is equal to about 70% to 100% of the semiconductor wafer diameter, said plurality of support fixtures and said wafer support means selected from the group of materials consisting of quartz, silicon carbide and graphite.

5. The vertical carrier means of claim 4 wherein said first diameter is about equal to 35.0% of the semiconductor wafer diameter and wherein said second diameter is about equal to 82.3% of the semiconductor wafer diameter.

6. The vertical carrier of claim 4, wherein some of said uniformly spaced projecting points in said first and said second arrays of projecting points have been removed to permit access for semiconductor wafer loading and unloading means.

7. A method for supporting a semiconductor wafer during thermal processing, comprising the steps of:

providing a semiconductor wafer support means comprising;

a support fixture comprising a plate-like member; and

a wafer support means consisting of first and second arrays of uniformly spaced projecting points having substantially the same height above said plate-like member, wherein said first and second arrays of projecting points are disposed on said support fixture at respective first and second concentric diameters, wherein said first diameter is equal to about 10% to 70% of a diameter of the semiconductor wafer and said second diameter is equal to about 70% to 100% of the semiconductor wafer diameter; and

placing said semiconductor wafer onto said wafer support means such that said semiconductor wafer is disposed about co-axially on said first and second support structures, said first and second support structures and said support fixture selected from the group consisting of quartz, silicon carbide and graphite.