System and method for optical wafer characterization with image upsampling

Abstract

The system includes a processing unit communicatively connected to a detector array of an optical wafer characterization system, the processing unit configured to perform one or more steps of a method or process including obtaining one or more target images of a target location on a wafer from the detector array, applying a noise reduction filter to at least the one or more target images, determining one or more difference images from one or more reference images and the one or more target images, and upsampling the one or more difference images to generate one or more upsampled images. One or more wafer defects are detectable in the one or more difference images or the one or more upsampled images.

Claims

1. It is a system, The system includes a processing unit that is communicatively connected to the detector array of an optical wafer characterization system. The aforementioned processing unit is From the detector array, one or more target images of target locations on the wafer are acquired. A noise reduction filter is applied to at least one or more of the target images to remove spatial frequencies exceeding a selection threshold, the selection threshold depends on the minimum wavelength in the spectrum of the detected light. From one or more reference images and the one or more denoised target images, one or more difference images are determined. The system is configured to generate one or more upsampled images by upsampling the one or more difference images through interpolation. In the one or more upsampled images, one or more wafer defects are detectable. The system is configured to pass the one or more upsampled images through an anomaly detector. The anomaly detector is configured to adjust or remove upsampled image pixel values ​​that exceed a set threshold.

2. The processing unit is configured to acquire one or more reference images from the detector array. The system according to claim 1, wherein the one or more reference images are of reference locations near the target location on the wafer.

3. The system according to claim 1, wherein the processing unit is configured to determine one or more difference images from the one or more reference images and the one or more target images by subtracting the one or more reference images from the one or more target images.

4. The system according to claim 1, wherein the noise reduction filter is a spatial frequency filter and is configured to remove a portion of the noise in at least one or more target images acquired by the detector array, and is configured to suppress changes in the noise-free image.

5. The spatial frequency filter is a Fast Fourier Transform (FFT) filter, The system according to claim 4, wherein the at least one or more target images are subjected to a Fourier transform by the FFT filter, multiplied by a function of spatial frequency, and then subjected to an inverse Fourier transform.

6. The spatial frequency filter is a finite impulse response (FIR) filter, The system according to claim 4, wherein the at least one or more target images are convolved by the FIR filter.

7. The processing unit applies the noise reduction filter to the one or more reference images. The system according to claim 1, configured to determine one or more difference images from the one or more reference images and the one or more target images after noise reduction of the one or more reference images and the one or more target images.

8. The system according to claim 1, wherein the processing unit includes a field-programmable gate array (FPGA), an application-specific integrated circuit, an image processing device, or a central processing unit.

9. The system according to claim 1, wherein the optical wafer characterization system is a broadband plasma (BBP) tool.

10. The processing unit is configured to determine one or more control signals based on one or more wafer defects detected in the one or more upsampled images. The system according to claim 1, wherein the one or more control signals are configured to perform one or more adjustments on at least one of the one or more optical wafer characterization components of the optical wafer characterization system and the one or more semiconductor manufacturing components of the semiconductor manufacturing system.

11. The processing unit is connected to the controller in a communication manner, The controller includes one or more processors and memory, The memory is configured to store program instructions. The one or more processors are configured to execute the program instructions, The program instructions are sent to the one or more processors: The processing unit receives the one or more upsampled images. Based on the one or more wafer defects detected in the one or more upsampled images, one or more control signals are determined. The system according to claim 1, wherein the one or more control signals are configured to perform one or more adjustments on at least one of the one or more optical wafer characterization components of the optical wafer characterization system and the one or more semiconductor manufacturing components of the semiconductor manufacturing system.

12. It is a method, The processing unit acquires one or more target images of target locations on the wafer from the detector array of the optical wafer characterization system, The process involves applying a noise reduction filter to at least one or more target images to remove spatial frequencies exceeding a selection threshold, wherein the selection threshold depends on the minimum wavelength in the spectrum of the detected light. The processing unit determines one or more difference images from one or more reference images and one or more target images, The processing unit generates one or more upsampled images by upsampling the one or more difference images by interpolation. In the one or more upsampled images, one or more wafer defects are detectable. The process involves passing one or more of the upsampled images through an anomaly detector, the anomaly detector being configured to adjust or remove upsampled image pixel values ​​that exceed a set threshold. method.

13. The processing unit further includes acquiring the one or more reference images from the detector array, The method according to claim 12, wherein the one or more reference images are of reference locations near the target location on the wafer.

14. The method according to claim 12, wherein determining one or more difference images from the one or more reference images and the one or more target images includes subtracting the one or more reference images from the denoised one or more target images.

15. The method according to claim 12, wherein the noise reduction filter is a spatial frequency filter and is configured to remove a portion of the noise in at least one or more target images acquired by the detector array, and is configured to suppress changes in the noise-free image.

16. The spatial frequency filter is a Fast Fourier Transform (FFT) filter, The method according to claim 15, wherein the at least one or more target images are Fourier transformed by the FFT filter, multiplied by a function of spatial frequency, and inverse Fourier transformed.

17. The spatial frequency filter is a finite impulse response (FIR) filter, The method according to claim 15, wherein the at least one or more target images are convolved by the FIR filter.

18. Applying the noise reduction filter to the one or more reference images, The method according to claim 12, further comprising: determining one or more difference images from the one or more reference images and the one or more target images after denoising the one or more reference images and the one or more target images.

19. The method according to claim 12, wherein the processing unit includes a field-programmable gate array (FPGA), an application-specific integrated circuit, an image processing device, or a central processing unit.

20. The method according to claim 12, wherein the optical wafer characterization system is a broadband plasma (BBP) tool.

21. The processing unit further includes determining one or more control signals based on one or more wafer defects detected in the one or more upsampled images. The method according to claim 12, wherein the one or more control signals are configured to perform one or more adjustments on at least one of the one or more optical wafer characterization components of the optical wafer characterization system and the one or more semiconductor manufacturing components of the semiconductor manufacturing system.

22. The processing unit is connected to the controller in a communication manner, The method described above involves the controller receiving one or more upsampled images from the processing unit, The controller further includes determining one or more control signals based on one or more wafer defects detected in the one or more upsampled images, The method according to claim 12, wherein the one or more control signals are configured to perform one or more adjustments on at least one of the one or more optical wafer characterization components of the optical wafer characterization system and the one or more semiconductor manufacturing components of the semiconductor manufacturing system.

23. An optical wafer characterization system, A light source configured to generate and emit light, A lighting arm having one or more lighting optical systems configured to irradiate a wafer placed on a stage assembly with light received from the light source, A focusing arm having one or more focusing optical systems, A detector array having one or more sensors, wherein the one or more focusing optical systems are configured to image the wafer onto the detector array, The system comprises a processing unit that is communicatively connected to the detector array, The aforementioned processing unit is From the detector array, one or more target images of the target location on the wafer are acquired. A noise reduction filter is applied to at least one or more of the target images to remove spatial frequencies exceeding a selection threshold, the selection threshold depends on the minimum wavelength in the spectrum of the detected light. From one or more reference images and the one or more denoised target images, one or more difference images are determined. The system is configured to generate one or more upsampled images by upsampling one or more of the aforementioned difference images. In the one or more upsampled images, one or more wafer defects are detectable. The one or more upsampled images are passed through an anomaly detector, which is configured to adjust or remove upsampled image pixel values ​​that exceed a set threshold. Optical wafer characterization system.

24. The processing unit is configured to acquire one or more reference images from the detector array. The optical wafer characteristic evaluation system according to claim 23, wherein the one or more reference images are of reference locations on the wafer near the target location.

25. The optical wafer characteristic evaluation system according to claim 23, wherein the processing unit is configured to determine one or more difference images from the one or more reference images and the denoised one or more target images by subtracting the one or more reference images from the one or more target images.

26. The optical wafer characteristic evaluation system according to claim 23, wherein the noise reduction filter is a spatial frequency filter and is configured to remove a portion of the noise in at least one or more target images acquired by the detector array, and is configured to suppress changes in the noise-free image.

27. The spatial frequency filter is a Fast Fourier Transform (FFT) filter, The optical wafer characteristic evaluation system according to claim 26, wherein the at least one or more target images are Fourier transformed by the FFT filter, multiplied by a function of spatial frequency, and inverse Fourier transformed.

28. The spatial frequency filter is a finite impulse response (FIR) filter, The optical wafer characteristic evaluation system according to claim 26, wherein the at least one or more target images are convolved by the FIR filter.

29. The processing unit applies the noise reduction filter to the one or more reference images. The optical wafer characteristic evaluation system according to claim 23, configured to determine one or more difference images from the one or more reference images and the one or more target images after noise reduction of the one or more reference images and the one or more target images.

30. The optical wafer characterization system according to claim 23, wherein the processing unit includes a field-programmable gate array (FPGA), an application-specific integrated circuit, an image processing device, or a central processing unit.

31. The optical wafer characterization system according to claim 23, wherein the optical wafer characterization system is a broadband plasma (BBP) tool equipped with a laser-excited plasma light source.

32. The processing unit is configured to determine one or more control signals based on one or more wafer defects detected in the one or more upsampled images. The optical wafer characterization system according to claim 23, wherein the one or more control signals are configured to perform one or more adjustments on at least one of the one or more optical wafer characterization components of the optical wafer characterization system and the one or more semiconductor manufacturing components of the semiconductor manufacturing system.

33. The optical wafer characteristic evaluation system is The processing unit further comprises a controller that is communicatively connected to the processing unit, The controller includes one or more processors and memory, The memory is configured to store program instructions. The one or more processors are configured to execute the program instructions, The program instructions are sent to the one or more processors: The processing unit receives the one or more upsampled images. Based on the one or more wafer defects detected in the one or more upsampled images, one or more control signals are determined. The optical wafer characterization system according to claim 23, wherein the one or more control signals are configured to perform one or more adjustments on at least one of the one or more optical wafer characterization components of the optical wafer characterization system and the one or more semiconductor manufacturing components of the semiconductor manufacturing system.

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