WAFER STAGE

• US 20100315617A1
• Filed: 06/12/2009
• Published: 12/16/2010
• Est. Priority Date: 06/12/2009
• Status: Active Grant

• Current Assignee: Semicaps Pte Limited
• Original Assignee: Semicaps Pte Limited
• Inventors: Chua, Wah Pheng, Chua, Choon Meng, Phang, Chee Hong Jacob, Koh, Lian Ser, Tan, Soon Huat
• Granted Patent: US 8,436,631 B2
• Time in Patent Office: Days
• US Class Current: 355/72
• CPC Class Codes: G03B 27/58 Baseboards, masking frames, or other holders for the sensitive material G03B27/53 takes precedence ; for electrophotographic copiers G03G15/65

Abstract

A wafer stage and a method of supporting a wafer for inspection. the wafer stage comprises a platform for supporting a wafer such that a backside of the wafer is suspended above a cavity of the platform; and a support structure disposed substantially within the cavity for supporting a portion of the wafer; wherein the wafer stage is adapted for relative movement of the platform with respect to the support structure for alignment of the wafer with respect to a probe.

Claims

1. A wafer stage, comprising:

a platform for supporting a wafer such that a backside of the wafer is suspended above a cavity of the platform; and

a support structure disposed substantially within the cavity for supporting a portion of the wafer;

wherein the wafer stage is adapted for relative movement of the platform with respect to the support structure for alignment of the wafer with respect to a probe.

2. The wafer stage according to claim 1, wherein the support structure comprises:

a support bar; and

a support element projecting from a top surface of the support bar for supporting the portion of the wafer.

3. The wafer stage according to claim 2, wherein the support element is hollow and is disposed around an aperture formed in the support bar enabling an optical inspection of the backside of the wafer through the hollow support element and the aperture.

4. The wafer stage according to claim 2, wherein the support bar is coupled to an anchor structure for inhibiting movement of the support bar in a plane parallel to the platform.

5. The wafer stage according to claim 4, wherein the anchor structure is adapted for allowing movement of the support structure in a direction perpendicular to said plane parallel to the platform.

6. The wafer stage according to claim 2, wherein the support bar is received in two slots formed in the platform and aligned across the cavity.

7. The wafer stage according to claim 2, wherein the hollow support is coated with or formed from a static dissipating low-friction material.

8. The wafer stage according to claim 7, wherein the support bar is coated with or formed from the static dissipating low-friction material.

9. The wafer stage according to claim 8, wherein the static dissipating low-friction material comprises PEEK Bearing Grade or Static-Dissipative Acetal Copolymer.

10. A method of supporting a wafer for inspection, the method comprising the steps of:

supporting the wafer such that a backside of the wafer is suspended above a cavity of a platform;

providing a support structure disposed substantially within the cavity for supporting a portion of the wafer; and

effecting relative movement of the platform with respect to the support structure for alignment of the wafer with respect to a probe.

11. The method according to claim 10, wherein the support structure comprises an support bar and a hollow support element disposed around an aperture formed in the support bar and projecting from a top surface of the support bar, and the method further comprises performing an optical inspection of the backside of the wafer through the hollow support element and the aperture.