Wafer bath imaging

Patent metadata

Field	Value
Publication number	US-2022405902-A1
Application number	US-202117349538-A
Country	US
Kind code	A1
Filing date	Jun 16, 2021
Priority date	Jun 16, 2021
Publication date	Dec 22, 2022
Grant date	—

Abstract

An exemplary method of monitoring a bath process includes processing a first wafer by submerging the first wafer within a bath solution; capturing a video of the bath solution containing the first wafer during a first time interval; analyzing the video based on intensity of light captured in a frame of the video; and based on analyzing the video, determining a first metric of the bath solution during the first time interval.

First claim

What is claimed is:

1 . A method of monitoring a bath process, the method comprising:
processing a first wafer by submerging the first wafer within a bath solution; capturing a video of the bath solution containing the first wafer during a first time interval; analyzing the video based on intensity of light captured in a frame of the video; and based on analyzing the video, determining a first metric of the bath solution during the first time interval.

2 . The method of claim 1 , wherein analyzing the video comprises selecting a region of the video to be analyzed and analyzing the same region in further frames of the video following the frame.

3 . The method of claim 1 ,
wherein analyzing the video comprises
dividing each frame of the video being analyzed into an array of pixels based on a sensor size of a camera capturing the video, and
calculating a pixel intensity of light for each of the array of pixels, and
wherein determining the first metric of the bath solution during the first time interval comprises determining the first metric based on the pixel intensity of light for each of the array of pixels.

4 . The method of claim 1 ,
wherein analyzing the video comprises
dividing each frame of the video being analyzed into a plurality of zones, and
calculating a zonal intensity of light in each of the plurality of zones, and
wherein determining the first metric of the bath solution during the first time interval comprises determining the first metric based on the zonal intensity of light in each of the plurality of zones.

5 . The method of claim 1 ,
wherein analyzing the video comprises
dividing each frame of the video being analyzed into an one dimensional array of regions, and
calculating a regional intensity of light for each of the array of regions, and
wherein determining the first metric of the bath solution during the first time interval comprises determining the first metric based on the regional intensity of light for each of the array of regions.

6 . The method of claim 1 ,
wherein analyzing the video comprises subtracting from the intensity of light captured in each frame of the video being analyzed a background intensity of light obtained for that frame.

7 . The method of claim 1 , wherein the first metric is determined dynamically during the processing of the first wafer.

8 . The method of claim 1 , wherein the first metric is determined after processing the first wafer.

9 . The method of claim 1 , wherein the first metric of the bath solution is based on a number of pixels above an intensity threshold.

10 . The method of claim 1 , wherein the first metric of the bath solution comprises a bubble count of bubbles in the bath solution.

11 . The method of claim 1 , further comprising determining a second metric of the bath solution during the first time interval based on analyzing the video, the second metric being based on a directionality of the intensity of light captured in each frame of the video being analyzed.

12 . The method of claim 1 , further comprising:
detecting a fault in processing the first wafer.

13 . The method of claim 12 , wherein detecting the fault comprises identifying that the first metric of the bath solution changes during the first time interval.

14 . The method of claim 12 , wherein detecting the fault comprises
determining a second metric of the bath solution during the processing of a second wafer, and determining the first metric is different from the second metric.

15 . The method of claim 1 , further comprising:
changing a process for the bath solution during a second time interval for processing the first wafer in the bath solution.

16 . The method of claim 1 , further comprising:
comparing the first metric of the bath solution with a second metric of another bath solution of a different processing tool; and matching the first metric of the bath solution with the second metric of the another bath solution by adjusting a process parameter of the bath solution.

17 . The method of claim 1 , further comprising:
changing a process for the bath solution during a second time interval for processing a second wafer.

18 . The method of claim 1 , wherein analyzing the video comprises determining a uniformity of the bath solution during the first time interval based on the intensity of light captured in each frame of the video being analyzed.

19 . The method of claim 1 , further comprising:
correlating the first metric of the bath solution with a process metric for a processing tool holding the bath solution.

20 . The method of claim 1 , further comprising:
capturing an audio of the bath solution during the first time interval; analyzing the audio based on an intensity of the audio; and based on analyzing the audio, determining an audio-based metric of the bath solution during the first time interval.

21 . A method of detecting wafer bridging, the method comprising:
submerging a plurality of wafers within a bath solution; illuminating a side of the plurality of wafers with a light source; capturing a first image of a first portion of the side of the plurality of wafers; and determining wafer bridging occurred between any one of the plurality of wafers based on the first image.

22 . The method of claim 21 , further comprising:
capturing a second image of a second portion of the side of the plurality of wafers, wherein determining wafer bridging occurred comprises comparing the first image with the second image.

23 . The method of claim 22 , wherein the first image and the second image are different frames of a video.

24 . The method of claim 21 , further comprising:
analyzing the first image to determine distance between adjacent ones of the plurality of wafers, wherein determining whether wafer bridging occurred comprises determining whether any of the distance between adjacent ones of the plurality of wafers is less than a threshold.

25 . The method of claim 21 , further comprising:
analyzing the first image to count a number of wafer in the plurality of wafers, wherein determining whether wafer bridging occurred comprises determining that the count is less than the actual number of wafers in the plurality of wafers.

Assignees

• Tokyo Electron Ltd

Inventors

• Estrella Joel
• Simms Ihsan
• Carcasi Michael
• Hooge Joshua
• Marumoto Hiroshi

Classifications

• H10P72/0604 Primary

  Process monitoring, e.g. flow or thickness monitoring · CPC title

• H10P72/0416

  with the semiconductor substrates being dipped in baths or vessels · CPC title

• G06T7/0004 Primary

  Industrial image inspection · CPC title

• G06T2207/20021

  Dividing image into blocks, subimages or windows · CPC title

• G06T2207/30148

  Semiconductor; IC; Wafer · CPC title