Inspection device and inspection method

• US 9,360,436 B2
• Filed: 11/13/2013
• Issued: 06/07/2016
• Est. Priority Date: 12/18/2012
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Hsieh, Yi-Chen, Chiang, Chih-Jung, Yang, Fu-Cheng
• Primary Examiner(s): Ustaris, Joseph
• Assistant Examiner(s): Ren, Zhubing
• Application Number:
  US14/079,568
• Publication Number:
  US 20140168417A1
• Time in Patent Office: 937 Days
• US Class Current: 1/1
• CPC Class Codes: G01N 2021/8848 Polarisation of light
• CPC Class Codes: G01N 21/21 Polarisation-affecting properties G01N21/19 takes precedence
• CPC Class Codes: G01N 21/8806 Specially adapted optical and illumination features
• CPC Class Codes: G01N 21/9501 Semiconductor wafers manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10
• CPC Class Codes: G02B 5/3066 involving the reflection of light at a particular angle of incidence, e.g. Brewster's angle

Abstract

The disclosure provides an inspection device including a light source module, an image receiving module and a processing unit. The light source module emits a first incident light and a second incident light to a device under test (DUT). The image receiving module receives a first image corresponding to the DUT irradiated by the first incident light, and receives a second image corresponding to the DUT irradiated by the second incident light. The processing unit calculates the contrast ratio of the first image and the second image to obtain a high-contrast image for inspection.

Claims

1. An inspection device, comprising:

a light source module, emitting a first incident light and a second incident light to a device under test (DUT);

an image receiving module, receiving a first image generated by the DUT irradiated by the first incident light and a second image generated by the DUT irradiated by the second incident light; and

a processor, calculating a contrast value of the first image and the second image to obtain a high contrast image for inspection;

wherein the DUT comprises a first testing region and a second testing region, and the image receiving module receives a first sub-image generated by the first incident light illuminating the first testing region, a second sub-image generated by the first incident light illuminating the second testing region, a third sub-image generated by the second incident light illuminating the first testing region, and a fourth sub-image generated by the second incident light illuminating the second testing region, and the processor utilizes a predetermined formula to calculate contrast values of the first sub-image, the second sub-image, the third sub-image and the fourth sub-image to obtain the high contrast image for inspection, wherein each of the first sub-image, the second sub-image, the third sub-image, the fourth sub-image and the high contrast image is divided into N regions by the following formula;

2. The inspection device as claimed in claim 1, wherein a wavelength of the first incident light is different from a wavelength of the second incident light.

3. The inspection device as claimed in claim 1, wherein an incident angle of the first incident light is different from an incident angle of the second incident light.

4. The inspection device as claimed in claim 1, wherein the light source module comprises a polarizer and a compensator, and the image receiving module comprises an analyzer and a photo-sensitive element, such that the first incident light and the second incident light pass through the polarizer and the compensator to the DUT, and the photo-sensitive element obtains the first image and the second image by the analyzer.

5. The inspection device as claimed in claim 4, wherein the optical axises of the polarizer, the compensator and/or the analyzer are different such that a polarizing configuration of the first incident light is different from a polarizing configuration of the second incident light.

6. The inspection device as claimed in claim 1, wherein the processor determines whether the DUT has defects by a gray-scale value of the high contrast image.

7. The inspection device as claimed in claim 1, wherein the light source module includes a first sub-light source module and a second sub-light source module emitting the first incident light and the second incident light to the DUT respectively, and the image receiving module further includes a first sub-image receiving module and a second sub-image receiving module respectively receiving a first image generated by the DUT irradiated by the first incident light and a second image generated by the DUT irradiated by the second incident light.

8. The inspection device as claimed in claim 7, wherein the first sub-image receiving module and the second sub-image receiving module respectively emit the first incident light and the second incident light to the DUT at the same time.

9. The inspection device as claimed in claim 7, wherein the first sub-light source module and the second sub-light source module respectively comprise a polarizer and a compensator, the first sub-image receiving module and the second sub-image receiving module further respectively comprise an analyzer and a photo-sensitive element, such that the first incident light and the second incident light pass through the polarizers and the compensators of the first sub-light source module and the second sub-light source module respectively to the DUT, and the photo-sensitive element obtains the first image and the second image by the analyzers of the first sub-image receiving module and the second sub-image receiving module respectively, wherein the optical axises of the polarizers, the compensators and/or the analyzers are different such that the polarizing configuration of the first incident light is different from the polarizing configuration of the second incident light.

10. An inspection method, applied to an inspection device, wherein the inspection device comprises a light source module, an image receiving module and a processor, the inspection method comprising:

emitting a first incident light and a second incident light to a device under test (DUT) by the light source module;

receiving a first image generated by the DUT irradiated by the first incident light and a second image generated by the DUT irradiated by the second incident light; and

calculating a contrast value of the first image and the second image to obtain a high contrast image for inspection by the processor;

wherein the DUT further comprises a first testing region and a second testing region, and the image receiving module receives a first sub-image generated by the first incident light illuminating the first testing region, a second sub-image generated by the first incident light illuminating the second testing region, a third sub-image generated by the second incident light illuminating the first testing region, and a fourth sub-image generated by the second incident light illuminating the second testing region, and the processor utilizes a predetermined formula to calculate the contrast values of the first sub-image, the second sub-image, the third sub-image and the fourth sub-image to obtain the high contrast image for inspection, wherein each of the first sub-image, the second sub-image, the third sub-image, the fourth sub-image and the high contrast image is divided into N regions by the following formula;

11. The inspection method as claimed in claim 10, wherein a wavelength of the first incident light is different from a wavelength of the second incident light.

12. The inspection method as claimed in claim 10, wherein an incident angle of the first incident light is different from an incident angle of the second incident light.

13. The inspection method as claimed in claim 10, wherein the first incident light and the second incident light pass through a polarizer and a compensator of the light source module to the DUT, and the first image and the second image are obtained by a photo-sensitive element of the image receiving module through an analyzer.

14. The inspection method as claimed in claim 13, wherein the optical axises of the polarizer, the compensator and/or the analyzer are different such that a polarizing configuration of the first incident light is different from a polarizing configuration of the second incident light.

15. The inspection method as claimed in claim 10, further comprising determining whether the DUT has defects by a gray-scale value of the high contrast image.

16. The inspection method as claimed in claim 10, wherein the light source module includes a first sub-light source module and a second sub-light source module emitting the first incident light and the second incident light to the DUT respectively, and the image receiving module includes a first sub-image receiving module and a second sub-image receiving module respectively receiving a first image generated by the DUT irradiated by the first incident light and a second image generated by the DUT irradiated by the second incident light.

17. The inspection method as claimed in claim 16, wherein the first sub-image receiving module and the second sub-image receiving module emit the first incident light and the second incident light to the DUT at the same time.

18. The inspection method as claimed in claim 16, wherein the first sub-light source module and the second sub-light source module respectively comprise a polarizer and a compensator, the first sub-image receiving module and the second sub-image receiving module further respectively comprise an analyzer and a photo-sensitive element, such that the first incident light and the second incident light pass through the polarizers and the compensators of the first sub-light source module and the second sub-light source module respectively to the DUT, and the photo-sensitive element obtains the first image and the second image by the analyzers of the first sub-image receiving module and the second sub-image receiving module respectively, wherein the optical axises of the polarizers, the compensators and/or the analyzers are different such that the polarizing configuration of the first incident light is different from the polarizing configuration of the second incident light.