System and method for determining post bonding overlay

Patent metadata

Field	Value
Publication number	US-12197137-B2
Application number	US-202318520244-A
Country	US
Kind code	B2
Filing date	Nov 27, 2023
Priority date	Dec 11, 2020
Publication date	Jan 14, 2025
Grant date	Jan 14, 2025

Abstract

A wafer shape metrology system includes a wafer shape metrology sub-system configured to perform one or more stress-free shape measurements on a first wafer, a second wafer, and a post-bonding pair of the first and second wafers. The wafer shape metrology system includes a controller communicatively coupled to the wafer shape metrology sub-system. The controller is configured to receive stress-free shape measurements from the wafer shape sub-system; predict overlay between one or more features on the first wafer and the second wafer based on the stress-free shape measurements of the first wafer, the second wafer, and the post-bonding pair of the first wafer and the second wafer; and provide a feedback adjustment to one or more process tools based on the predicted overlay. Additionally, feedforward and feedback adjustments may be provided to one or more process tools.

First claim

What is claimed:

1. A wafer shape metrology system comprising:
a wafer shape metrology sub-system configured to perform one or more stress-free shape measurements on a first wafer and a second wafer; and
a controller communicatively coupled to the wafer shape metrology sub-system, the controller including one or more processors configured to execute a set of program instructions stored in a memory, the set of program instructions configured to cause the one or more processors to:
receive the one or more stress-free shape measurements for the first wafer and the second wafer from the wafer shape sub-system;
determine a first wafer shape distortion of the first wafer by comparing the first wafer shape to a first reference structure and determine a second wafer shape distortion of the second wafer by comparing the second wafer shape to a second reference structure;
predict overlay between one or more features on the first wafer and one or more features on the second wafer based on the one or more stress-free shape measurements of the first wafer and the second wafer, the first wafer shape distortion, and the second wafer shape distortion; and
provide a feedforward adjustment to one or more process tools based on the predicted overlay.

2. The wafer shape metrology system of claim 1 , wherein at least one of the first reference structure or the second reference structure comprises an idealized flat plate.

3. The system of claim 1 , wherein the providing one or more feedforward control to one or more process tools based on the predicted overlay comprises:
providing one or more feedforward control signals to a bonder based on the predicted overlay.

4. The system of claim 1 , wherein the wafer shape metrology sub-system comprises a first interferometer sub-system and a second interferometer sub-system.

5. The system of claim 1 , wherein the predicting overlay between one or more features on the first wafer and one or more features on the second wafer based on the one or more stress-free shape measurements of the first wafer and the second wafer, the first shape distortion, and the second wafer shape distortion comprises:
extracting one or more wafer shape parameters from the one or more stress-free shape measurements of the first wafer and the second wafer.

6. The system of claim 5 , further comprising:
inputting the extracted one or more wafer shape parameters of the first wafer and the second wafer and the first shape distortion and the second wafer shape distortion into a mechanical model to predict overlay between one or more features on the first wafer and one or more features on the second wafer.

7. The system of claim 5 , wherein the extracted one or more wafer shape parameters comprises at least one of local shape curvature (LSC) or in-plane distortion (IPD).

8. The system of claim 5 , further comprising:
inputting the extracted one or more wafer shape parameters of the first wafer and the second wafer and the first shape distortion and the second wafer shape distortion into a machine learning algorithm to predict overlay between one or more features on the first wafer and one or more features on the second wafer.

9. The system of claim 8 , furthering comprising:
training the machine learning algorithm.

10. The system of claim 9 , wherein the training the machine learning algorithm comprises:
training the machine learning algorithm with infrared overlay data.

11. A system comprising:
a controller configured to receive wafer shape measurements from a wafer shape metrology sub-system, the controller including one or more processors configured to execute a set of program instructions stored in a memory, the set of program instructions configured to cause the one or more processors to:
receive one or more stress-free shape measurements for a first wafer and a second wafer from the wafer shape sub-system;
determine a first wafer shape distortion of the first wafer by comparing the first wafer shape to a first reference structure and determine a second wafer shape distortion of the second wafer by comparing the second wafer shape to a second reference structure;
predict overlay between one or more features on the first wafer and one or more features on the second wafer based on the one or more stress-free shape measurements of the first wafer and the second wafer, the first wafer shape distortion, and the second wafer shape distortion; and
provide a feedforward adjustment to one or more process tools based on the predicted overlay.

12. The wafer shape metrology system of claim 11 , wherein at least one of the first reference structure or the second reference structure comprises an idealized flat plate.

13. The system of claim 11 , wherein the providing one or more feedforward control to one or more process tools based on the predicted overlay comprises:
providing one or more feedforward control signals to a bonder based on the predicted overlay.

14. The system of claim 11 , wherein the wafer shape metrology sub-system comprises a first interferometer sub-system and a second interferometer sub-system.

15. The system of claim 11 , wherein the predicting overlay between one or more features on the first wafer and one or more features on the second wafer based on the one or more stress-free shape measurements of the first wafer and the second wafer, the first shape distortion, and the second wafer shape distortion comprises:
extracting one or more wafer shape parameters from the one or more stress-free shape measurements of the first wafer and the second wafer.

16. The system of claim 15 , further comprising:
inputting the extracted one or more wafer shape parameters of the first wafer and the second wafer and the first shape distortion and the second wafer shape distortion into a mechanical model to predict overlay between one or more features on the first wafer and one or more features on the second wafer.

17. The system of claim 15 , wherein the extracted one or more wafer shape parameters comprises at least one of local shape curvature (LSC) or in-plane distortion (IPD).

18. The system of claim 15 , further comprising:
inputting the extracted one or more wafer shape parameters of the first wafer and the second wafer and the first shape distortion and the second wafer shape distortion into a machine learning algorithm to predict overlay between one or more features on the first wafer and one or more features on the second wafer.

19. The system of claim 18 , furthering comprising:
training the machine learning algorithm.

20. The system of claim 19 , wherein the training the machine learning algorithm comprises:
training the machine learning algorithm with infrared overlay data.

21. A method comprising:
acquiring one or more stress-free shape measurements for a first wafer and a second wafer;
determining a first wafer shape distortion of the first wafer by comparing the first wafer shape to a first reference structure and determine a second wafer shape distortion of the second wafer by comparing the second wafer shape to a second reference structure;
predicting overlay between one or more features on the first wafer and one or more features on the second wafer based on the one or more stress-free shape measurements of the first wafer and the second wafer, the first wafer shape distortion, and the second wafer shape distortion; and
providing a feedforward adjustment to one or more process tools based on the predicted overlay.

Assignees

• Kla Corp

Inventors

• Zach Franz
• Smith Mark D
• Shen Xiaomeng
• Saito Jason
• Owen David

Classifications

• H10P74/203 Primary

  Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects · CPC title

• H10P74/23

  characterised by multiple measurements, corrections, marking or sorting processes · CPC title

• H10P72/0616

  Monitoring of warpages, curvatures, damages, defects or the like · CPC title

• H10W99/00

  Subject matter not provided for in other groups of this subclass · CPC title

• G03F7/70633 Primary

  Overlay, i.e. relative alignment between patterns printed by separate exposures in different layers, or in the same layer in multiple exposures or stitching · CPC title