Systems and methods for wafer alignment

Patent metadata

Field	Value
Publication number	US-10347519-B2
Application number	US-201916248500-A
Country	US
Kind code	B2
Filing date	Jan 15, 2019
Priority date	Jun 1, 2016
Publication date	Jul 9, 2019
Grant date	Jul 9, 2019

Abstract

Various embodiments of aligning wafers are described herein. In one embodiment, a photolithography system aligns a wafer by averaging individual via locations. In particular, some embodiments of the present technology determine the center locations of individual vias on a wafer and average them together to obtain an average center location of the set of vias. Based on a comparison of the average center location to a desired center location, the present technology adjusts the wafer position. Additionally, in some embodiments, the present technology compares wafer via patterns to a template and adjusts the position of the water based on the comparison.

First claim

We claim:

1. A system for aligning a wafer, the system comprising a controller configured to:
determine a center location of each of a plurality of features on the wafer;
determine an average center location of the plurality of features;
compare the average center location with a reference location; and
adjust a position of the wafer in response to the comparison.

2. The system of claim 1 , wherein the controller is configured to determine the center location of each of the plurality of features by detecting intensity of light reflected from the plurality of features.

3. The system of claim 1 , wherein the controller is configured to determine the center location of each of the plurality of features based either on shape recognition or on image pattern recognition.

4. The system of claim 1 , wherein the reference location is a center of a camera view field or a reference point associated with the wafer.

5. The system of claim 1 , wherein the controller is configured to adjust the position of the wafer by moving a substrate support configured to hold the wafer.

6. The system of claim 1 , wherein the controller is configured to determine the average center location by computing a mean, median, or weighted average of the determined center locations.

7. The system of claim 1 , wherein the controller is configured to determine the center location of each of the plurality of features by computing an x and y coordinate for each of the plurality of features.

8. The system of claim 7 , wherein the controller is configured to determine the average center location by computing an average x and y coordinate for the average center location.

9. The system of claim 1 , further comprising an electrical motor configured to move the wafer.

10. A method for aligning a wafer, comprising:
determining a center location of each of a plurality of features on the wafer;
determining an average center location of the plurality of features;
comparing the average center location with a reference location; and
adjusting a position of the wafer in response to the comparison.

11. The method of claim 10 , wherein determining the center location of each of the plurality of features comprises detecting intensity of light reflected from the plurality of features.

12. The method of claim 10 , wherein determining the center location of each of the plurality of features comprises shape recognition or image pattern recognition.

13. The method of claim 10 , wherein the reference location is a center of a camera view field or a reference point associated with the wafer.

14. The method of claim 10 , wherein adjusting the position of the wafer comprises moving a substrate support configured to hold the wafer.

15. The method of claim 10 , wherein determining the average center location comprises computing a mean, median, or weighted average of the determined center locations.

16. The method of claim 10 , wherein determining the center location of each of the plurality of features comprises computing an x and y coordinate for each of the plurality of features.

17. The method of claim 16 , wherein determining the average center location comprises computing an average x and y coordinate for the average center location.

18. The method of claim 10 , wherein adjusting the position of the wafer comprises using an electrical motor to move the wafer.

Assignees

• Micron Technology Inc

Inventors

• Chao Yang
• Ypma Keith E
• Strauch Steve J

Classifications

• H10P72/53 Primary

  using optical controlling means · CPC title

• G01B11/14

  for measuring distance or clearance between spaced objects or spaced apertures (G01B11/26 takes precedence; rangefinders G01C3/00) · CPC title

• G03F9/7088

  Alignment mark detection, e.g. TTR, TTL, off-axis detection, array detector, video detection · CPC title

• G03F9/7015

  Reference, i.e. alignment of original or workpiece with respect to a reference not on the original or workpiece · CPC title

• B65G2811/0626

  Orientation of articles · CPC title