Etching methods

• US 6,344,364 B1
• Filed: 08/23/2000
• Issued: 02/05/2002
• Est. Priority Date: 03/27/1998
• Status: Expired due to Term

• Current Assignee: Aptina Imaging Corporation (ON Semiconductor Corporation)
• Original Assignee: Micron Technology, Inc.
• Inventors: Gilton, Terry
• Primary Examiner(s): Mills, Gregory
• Assistant Examiner(s): GOUDREAU, GEORGE A
• Application Number:
  US09/645,057
• Time in Patent Office: 531 Days
• Field of Search: 438/5, 438/7, 438/8, 438/9, 438/14, 438/16, 438/605, 438/714, 216/59, 216/60, 216/62
• US Class Current: 438/14
• CPC Class Codes: H01L 22/26 Acting in response to an ongoing measurement without interruption of processing, e.g. endpoint detection, in-situ thickness measurement endpoint detection arrangements in CMP apparatus B24B37/013, in discharge apparatus H01J37/32

Abstract

In one aspect, the invention includes a method of etching, comprising: a) forming a material over a substrate, the material comprising a lower portion near the substrate and an upper portion above the lower portion; b) providing a quantity of detectable atoms within the material, the detectable atoms being provided at a different concentration in the lower portion than in the upper portion; c) etching into the material and forming etching debris; and d) detecting the detectable atoms in the debris. In another aspect, the invention includes a method of etching, comprising: a) providing a semiconductor wafer substrate, the substrate having a center and an edge; b) forming a material over the substrate, the material comprising detectable atoms; c) etching into the material and forming etching debris; d) detecting the detectable atoms in the debris; and e) estimating a degree of center-to-edge uniformity of the etching from the detecting.

Claims

1. A method of etching, comprising:

providing a semiconductor wafer substrate having a center and an edge;

forming a material comprising detectable atoms over the substrate;

etching into the material and forming etching debris;

detecting the detectable atoms in the debris;

estimating a degree of center-to-edge uniformity of the etching from the detecting; and

wherein the detectable atoms comprise atoms selected from the group consisting of yttrium, lanthanides, actinides, calcium, magnesium, and mixtures thereof.

3. The method of claim 1 wherein the detectable atoms comprise yttrium atoms.

4. The method of claim 1 wherein the detectable atoms comprise lanthanide atoms.

5. The method of claim 1 wherein the detectable atoms comprise actinide atoms.

6. The method of claim 1 wherein the detectable atoms comprise calcium atoms.

7. The method of claim 1 wherein the detectable atoms comprise magnesium atoms.

2. A method of monitoring center-to-edge uniformity of an etch occurring on a semiconductor wafer assembly, comprising:

providing a semiconductor wafer, the wafer having a center and an edge;

forming alternating first and second layers over the semiconductor wafer, the alternating layers and the semiconductive wafer together comprising a semiconductive wafer assembly, the alternating layers comprising at least one first layer and at least one second layer, the first layer comprising a first material and the second layer comprising a second material, the second material comprising indicator atoms at a higher concentration than the first material;

etching through one or more of the alternating layers, the etching forming debris;

monitoring the debris for the indicator atoms to determine when the etch has penetrated the second material;

ascertaining the length of time during which indicator atoms are detected;

determining a degree of center-to-edge uniformity of the etching from said length of time; and

wherein the indicator atoms comprise atoms selected from the group consisting of yttrium, lanthanides, actinides, calcium, magnesium and mixtures thereof.

8. The method of claim 2 wherein the detectable atoms comprise yttrium atoms.

9. The method of claim 2 wherein the detectable atoms comprise lanthanide atoms.

10. The method of claim 2 wherein the detectable atoms comprise actinide atoms.

11. The method of claim 2 wherein the detectable atoms comprise calcium atoms.

12. The method of claim 2 wherein the detectable atoms comprise magnesium atoms.