Edge bead control method and apparatus

• US 6,887,801 B2
• Filed: 07/18/2003
• Issued: 05/03/2005
• Est. Priority Date: 07/18/2003
• Status: Expired due to Fees

• Current Assignee: II-VI Delaware, Inc. (Coherent Corp.)
• Original Assignee: Finisar Corporation (II-VI Incorporated)
• Inventors: Li, Bernard Q.
• Primary Examiner(s): GHYKA, ALEXANDER G
• Application Number:
  US10/623,351
• Publication Number:
  US 20050014390A1
• Time in Patent Office: 655 Days
• Field of Search: 438/778, 438/780, 438/782, 427/240
• US Class Current: 438/780
• CPC Class Codes: H01L 21/6838 with gripping and holding devices using a vacuum; Bernoulli devices

Abstract

Methods and devices for handling wafers during wafer processing are provided. One embodiment includes an apparatus for holding a wafer. The holding apparatus includes a pocket for receiving a wafer, and may include a mechanism allowing for the wafer to be secured within the pocket. Methods are also included for preparing a wafer for fabrication processes by the use of a wafer holding apparatus. These methods may include applying a layer of photoresist to the surface of a wafer.

Claims

1. A method of preparing a wafer for a fabrication process, the method comprising:

providing a wafer receiving apparatus for receiving a wafer of a first size, the wafer receiving apparatus including a recessed portion having a depth;

placing a wafer of the first size in the recessed portion of the wafer receiving apparatus;

applying photoresist to the wafer;

spinning the wafer and the wafer receiving apparatus while the wafer is placed in the recessed portion of the wafer receiving apparatus; and

wherein the wafer receiving apparatus further includes a circumferential groove in the recessed portion, wherein the method further comprises;

allowing a fluid to enter the circumferential groove; and

causing the fluid in the circumferential groove to expand and release the wafer from the pocket.

2. The method of claim 1 wherein the spinning step is performed such that the spinning distributes the photoresist onto both the wafer and the wafer receiving apparatus.

3. The method of claim 1 wherein the depth of the recessed portion is selected to flatten the photoresist profile on the wafer.

4. The method of claim 3 wherein the depth of the recessed portion is substantially equal to the thickness of the wafer.

5. The method of claim 1 wherein the wafer receiving apparatus further includes a channel coupled to the recessed portion, the channel adapted to allow a vacuum force to be applied within the recessed portion.

6. The method of claim 5 further comprising:

applying a vacuum force via the channel after the wafer is placed, the vacuum force being applied such that the wafer is held in place in the recessed portion.

7. A method of reducing edge bead thickness while applying photoresist to a wafer comprising:

providing a wafer receiving apparatus for receiving a wafer of a first size, the wafer receiving apparatus including a pocket having a depth, wherein the depth is chosen to correspond to a wafer of the first size;

placing a wafer of the first size in the pocket of the wafer receiving apparatus;

applying photoresist to the wafer;

spinning the wafer and the wafer receiving apparatus while the wafer is placed in the pocket to create a photoresist layer of a desired thickness; and

wherein the wafer receiving apparatus is sized to be compatible with machines adapted for use with wafers of a second size larger than the first size.

8. The method of claim 7 wherein the depth is greater than the thickness of the wafer.

9. The method of claim 7 wherein the depth is less than the thickness of the wafer plus the thickness of the desired photoresist layer.

10. The method of claim 7 wherein the depth is substantially equal to the thickness of the wafer.

11. The method of claim 7 wherein the first size is the size of a three inch wafer, and the second size is the size of a four inch wafer.

12. The method of claim 7 further comprising securing the wafer in the pocket.

13. The method of claim 7 wherein the wafer receiving apparatus further includes a channel coupled to the recessed portion, the channel adapted to allow a vacuum force to be applied within the recessed portion and wherein the step of securing the wafer in the pocket includes:

applying a vacuum force via the channel after the wafer is placed, the vacuum force being applied such that the wafer is held in place in the recessed portion.

14. The method of claim 7 wherein the wafer receiving apparatus further includes a circumferential groove in the recessed portion, wherein the method further comprises:

allowing a fluid to enter the circumferential groove; and

causing the fluid in the circumferential groove to expand and release the wafer from the pocket.

15. A method of reducing edge bead thickness while applying photoresist to a wafer comprising:

providing a wafer receiving apparatus for receiving a wafer of a first size, the wafer receiving apparatus including a pocket having a depth, wherein the depth is chosen to correspond to a wafer of the first size;

placing a wafer of the first size in the pocket of the wafer receiving apparatus;

applying photoresist to the wafer;

spinning the wafer and the wafer receiving apparatus while the wafer is placed in the pocket to create a photoresist layer of a desired thickness; and

wherein the depth is less than the thickness of the wafer plus the thickness of the desired photoresist layer.

16. A method of reducing edge bead thickness while applying photoresist to a wafer comprising:

providing a wafer receiving apparatus for receiving a wafer, the wafer receiving apparatus being sized to be compatible with machines adapted for use with wafers of a second size larger than wafers of a first size, the wafer receiving apparatus including a pocket having a depth, wherein the depth is chosen to correspond to a wafer of the first size;

placing a wafer of the first size in the pocket of the wafer receiving apparatus;

applying photoresist to the wafer;

spinning the wafer and the wafer receiving apparatus while the wafer is placed in the pocket to create a photoresist layer of a desired thickness; and

wherein the first size is the size of a three inch wafer, and the second size is the size of a four inch wafer.

17. A method of reducing edge bead thickness while applying photoresist to a wafer comprising:

providing a wafer receiving apparatus for receiving a wafer of a first size, the wafer receiving apparatus including a pocket having a depth, wherein the depth is chosen to correspond to a wafer of the first size;

placing a wafer of the first size in the pocket of the wafer receiving apparatus;

applying photoresist to the wafer;

spinning the wafer and the wafer receiving apparatus while the wafer is placed in the pocket to create a photoresist layer of a desired thickness; and

wherein the wafer receiving apparatus further includes a circumferential groove in the recessed portion, wherein the method further comprises;

allowing a fluid to enter the circumferential groove; and

causing the fluid in the circumferential groove to expand and release the wafer from the pocket.