Optical end-pointing for integrated circuit delayering; systems and methods using the same

Patent metadata

Field	Value
Publication number	US-12236573-B2
Application number	US-202117539333-A
Country	US
Kind code	B2
Filing date	Dec 1, 2021
Priority date	Dec 3, 2020
Publication date	Feb 25, 2025
Grant date	Feb 25, 2025

Abstract

Systems for determining an end-point of a delayering process using optical end-point detection are described. In embodiments, the systems include a controller with an optical end-pointing (OE) module that is configured to determine an end-point of a delayering process based at least in part on the color or thickness of a surface layer of an integrated circuit (IC). In embodiments, the OE module determines whether an end-point of the delayering process has been reached based at least in part on a comparison of a determined thickness of an IC surface layer to a target thickness. The thickness of the surface layer may be determined by the OE module using a machine learning model, such as a convolutional neural network. Methods of identifying an end-point of a delayering process are also described.

First claim

What is claimed:

1. A system for delayering integrated circuits (ICs), comprising an optical sensor and a controller, the controller comprising a processor, a memory comprising an optical end-point (OE) module, and communications circuitry;
wherein:
the communications circuitry is configured to communicatively couple with delayering equipment that is configured to perform a delayering process on an IC;
the sensor is configured to image a surface of an IC during or after execution the delayering process by said delayering equipment, and to transmit a sensor signal indicative of a color of a surface layer of the IC to said controller;
in response to said sensor signal, the OE module is configured to cause the controller to:
determine the color of the surface layer of the IC;
determine a thickness of the surface layer of the IC based at least in part on the determined color; and
determine whether an end-point of said delayering process has been reached based at least in part on the determined thickness.

2. The system of claim 1 , wherein the memory comprises calibration data stored therein, and the OE module is configured to cause the controller to determine the thickness of the surface layer using said calibration data and said determined color of the surface layer.

3. The system of claim 1 , wherein the OE module is configured to cause the controller to determine whether an end-point of said delayering process has been reached at least in part by comparing the determined thickness to a target thickness.

4. The system of claim 3 , wherein when the determined thickness is greater than the target thickness, the OE module is configured to cause the controller module to determine that the end-point of the delayering process has not been reached.

5. The system of claim 3 , wherein when the determined thickness is less than or equal to the target thickness, the OE module is configured to cause the controller module to determine that the end-point of the delayering process has been reached.

6. The system of claim 1 , wherein the OE module is configured to determine the thickness of the surface layer of the IC using a machine learning model.

7. The system of claim 6 , wherein the machine learning model is a convolutional neural network (CNN) model.

8. The system of claim 1 , wherein the surface layer of the IC comprises a dielectric material.

9. The system of claim 8 , wherein the dielectric material comprises SiO 2 , SiO, SiO x , or a combination of two or more thereof.

10. The system of claim 3 , wherein the OE module is further configured to cause the communications circuitry to issue a control signal to the delayering equipment, wherein the control signal is configured to cause the delayering equipment to continue performance of the delayering operation when the determined thickness is greater than the target thickness, and to stop performance of the delayering operation when the determined thickness is less than or equal to the target thickness.

11. A method of delayering an integrated circuit (IC), comprising:
imaging, with an optical sensor, a surface of an IC during or after performance of a delayering process by delayering equipment and producing a sensor signal indicative of a color of a surface layer of said IC;
receiving the sensor signal with a controller comprising a processor and a memory comprising an optical end-point (OE) module; and
with the OE module:
determining the color of the surface layer based at least in part on the sensor signal;
determining a thickness of the surface layer based at least in part on the determined color; and
determining whether an end-point of the delayering process has been reached based at least in part on the determined thickness.

12. The method of claim 11 , wherein determining the thickness of the surface layer is performed using calibration data stored in the memory of the controller and said determined color of the surface layer.

13. The method of claim 11 , wherein determining whether the end-point of the delayering process has been reached comprises comparing the determined thickness to a target thickness.

14. The method of claim 13 , wherein when the determined thickness is greater than the target thickness, the OE module determines that the end-point of the delayering process has not been reached.

15. The method of claim 8 , wherein when the determined thickness is less than or equal to the target thickness, the OE module determines that the end-point of the delayering process has been reached.

16. The method of claim 11 , wherein determining the thickness of the surface layer is performed with a machine learning model.

17. The method of claim 16 , wherein the machine learning model is a convolutional neural network (CNN) model.

18. The method of claim 11 , wherein the surface layer of the IC comprises a dielectric material.

19. The method of claim 18 , wherein the dielectric material comprises SiO 2 , SiO, SiO x , or a combination of two or more thereof.

20. The method of claim 13 , wherein the controller further comprises communications circuitry, and the method further comprises causing the communications circuitry to issue a control signal to the delayering equipment, wherein the control signal is configured to cause the delayering equipment to continue performance of the delayering operation when the determined thickness is greater than the target thickness, and to stop performance of the delayering operation when the determined thickness is less than or equal to the target thickness.

Assignees

• Battelle Memorial Institute

Inventors

• Scholl Jonathan
• Darby Nicholas
• Baur Joshua

Classifications

• G01N1/32 Primary

  Polishing; Etching · CPC title

• G06T2207/20081

  Training; Learning · CPC title

• G06T2207/20084

  Artificial neural networks [ANN] · CPC title

• G06T2207/30148

  Semiconductor; IC; Wafer · CPC title

• G06T7/90

  Determination of colour characteristics · CPC title