Bidirectional off-axis alignment deviation measurement method, system and off-axis marking

Abstract

This invention discloses a bidirectional off-axis alignment deviation measurement method, system, and off-axis marker. By adjusting the relative displacement of the optical axis of the imaging device and the sample under test along the X-axis or Y-axis, the imaging device captures an image of the target marker, a first reference marker image, and a second reference marker image; the target marker is located at the target alignment unit of the sample under test. Based on the target marker image and the first reference marker image, the X-axis alignment deviation of the target alignment unit in the sample under test is calculated; based on the target marker image and the second reference marker image, the Y-axis alignment deviation of the target alignment unit in the sample under test is calculated.

Claims

1. A method for measuring bidirectional off-axis alignment deviation, comprising the following steps: By adjusting the relative displacement of the optical axis of the imaging device and the sample under test in the X-axis or Y-axis, the imaging device captures a target marker image, a first reference marker image, and a second reference marker image. The target marker image includes the target marker, the first reference marker image includes the first reference marker, and the second reference marker image includes the second reference marker. The target marker is located at the target alignment unit of the sample under test. The Y-axis distance between the first reference marker and the target marker is greater than the Y-axis distance between the second reference marker and the target marker, and the X-axis distance between the second reference marker and the target marker is greater than the X-axis distance between the first reference marker and the target marker. Based on the target marker image and the first reference marker image, the X-axis alignment deviation of the target alignment unit in the sample under test is calculated. Based on the target marker image and the second reference marker image, the Y-axis alignment deviation of the target alignment unit in the sample under test is calculated.

2. The bidirectional off-axis alignment deviation measurement method as described in claim 1, wherein, The target marker includes a first sub-target marker and a second sub-target marker; by adjusting the relative displacement between the optical axis of the imaging device and the sample under test in the X-axis or Y-axis, the imaging device captures an image of the target marker, an image of the first reference marker, and an image of the second reference marker, including: by adjusting the relative displacement between the optical axis of the imaging device and the sample under test in the X-axis or Y-axis, the imaging device captures an image of the first sub-target marker, an image of the first reference marker, an image of the second sub-target marker, and an image of the second reference marker; the first sub-target marker image includes the first sub-target marker, and the second sub-target marker image includes the second sub-target marker; based on the target marker image and the first reference marker image, the X-axis alignment deviation of the target alignment unit in the sample under test is calculated; based on the target marker image and the second reference marker image, the Y-axis alignment deviation of the target alignment unit in the sample under test is calculated, including: Based on the first sub-target marker image and the first reference marker image, the X-axis alignment deviation of the target alignment unit in the sample under test is calculated; based on the second sub-target marker image and the second reference marker image, the Y-axis alignment deviation of the target alignment unit in the sample under test is calculated.

3. The bidirectional off-axis alignment deviation measurement method as described in claim 1, wherein the target alignment unit shares a first reference mark with one or more other alignment units on the sample to be tested, and / or, the target alignment unit shares a second reference mark with one or more other alignment units on the sample to be tested.

4. The bidirectional off-axis alignment deviation measurement method as described in any one of claims 1 to 3, wherein both the first reference mark and the second reference mark are located in the lower layer material of the target alignment unit.

5. The bidirectional off-axis alignment deviation measurement method as described in claim 1, wherein the first reference mark is located in the first alignment unit of the sample to be tested, and the second reference mark is located in the second alignment unit of the sample to be tested.

6. The bidirectional off-axis alignment deviation measurement method as described in claim 1, wherein the first reference mark and the second reference mark are located in the same other alignment unit of the sample to be tested.

7. The bidirectional off-axis alignment deviation measurement method as described in claim 5, wherein the first alignment unit, the second alignment unit, and the target alignment unit are all located in the same layer of the sample to be tested.

8. The bidirectional off-axis alignment deviation measurement method as claimed in claim 1, wherein the first reference mark is located on another alignment unit on the sample to be tested, and the second reference mark is located on the underlying material of the target alignment unit; or, the second reference mark is located on another alignment unit on the sample to be tested, and the first reference mark is located on the underlying material of the target alignment unit.

9. The bidirectional off-axis alignment deviation measurement method as described in claim 1 or 8, wherein the target alignment unit is a first wafer or a diced wafer, and the underlying material of the target alignment unit is a second wafer.

10. The bidirectional off-axis alignment deviation measurement method as described in claim 1, wherein the bidirectional off-axis alignment deviation measurement method is applied to the alignment of the target alignment unit and the preceding layer material in photolithography; the target alignment unit is a photoresist layer, and the preceding layer material is a material formed in the sample to be tested prior to the photoresist layer.

11. The bidirectional off-axis alignment deviation measurement method as described in claim 1, wherein the target marker image, the first reference marker image, and the second reference marker image are captured by the imaging device by adjusting the relative displacement between the optical axis of the imaging device and the sample under test in the X-axis or Y-axis, comprising: By adjusting the relative displacement of the optical axis of the imaging device and the sample under test in the X-axis or Y-axis, the imaging device captures a first target mark image, a first reference mark image, a second target mark image, and a second reference mark image. Based on the target mark image and the first reference mark image, the X-axis alignment deviation of the target alignment unit in the sample under test is calculated. Based on the target mark image and the second reference mark image, the Y-axis alignment deviation of the target alignment unit in the sample under test is calculated, including: based on the first target mark image and the first reference mark image, the X-axis alignment deviation of the target alignment unit in the sample under test is calculated; based on the second target mark image and the second reference mark image, the Y-axis alignment deviation of the target alignment unit in the sample under test is calculated.

12. A bidirectional off-axis alignment deviation measurement system, comprising: An imaging device and a computing device are electrically connected to each other. The imaging device is used to capture a target marker image, a first reference marker image, and a second reference marker image by measuring the relative displacement of its own optical axis with the sample under test along the X-axis or Y-axis; and to transmit the target marker image, the first reference marker image, and the second reference marker image to the computing device. The target marker image includes a target marker, the first reference marker image includes a first reference marker, and the second reference marker image includes a second reference marker. The target marker is located at a target alignment unit on the sample under test. The Y-axis distance between the first reference marker and the target marker is greater than the Y-axis distance between the second reference marker and the target marker, and the X-axis distance between the second reference marker and the target marker is greater than the X-axis distance between the first reference marker and the target marker. The computing device is used to calculate the X-axis alignment deviation of the target alignment unit on the sample under test based on the target marker image and the first reference marker image; and to calculate the Y-axis alignment deviation of the target alignment unit on the sample under test based on the target marker image and the second reference marker image.

13. The bidirectional off-axis alignment deviation measurement system as claimed in claim 12, wherein the imaging device includes a light source, an optical path assembly, a stage, and an imaging assembly; the imaging assembly includes a detector and a processor; wherein, The stage is used to hold the sample to be tested; the detector is electrically connected to the processor; the light source is used to emit a probe beam to the optical path assembly; the optical path assembly is used to transmit the probe beam to the surface of the sample to be tested and transmit the light reflected from the surface of the sample to the detector; the detector is used to convert the collected reflected light into an electrical signal and transmit it to the processor; the processor is used to generate an image based on the electrical signal.

14. The bidirectional off-axis alignment deviation measurement system as claimed in claim 13, wherein the light source is an infrared light source and the response band of the imaging component includes the emission band of the infrared light source.

15. A bidirectional off-axis alignment deviation measurement system as claimed in any one of claims 12 to 14, wherein the target marker includes a first sub-target marker and a second sub-target marker; the imaging device is specifically configured to: acquire an image of the first sub-target marker, an image of the first reference marker, an image of the second sub-target marker, and an image of the second reference marker by adjusting the relative displacement between the optical axis of the imaging device and the sample under test in the X-axis or Y-axis; the first sub-target marker image includes the first sub-target marker, and the second sub-target marker image includes the second sub-target marker; the computing device is specifically configured to: calculate the X-axis alignment deviation of the target alignment unit in the sample under test based on the first sub-target marker image and the first reference marker image; and calculate the Y-axis alignment deviation of the target alignment unit in the sample under test based on the second sub-target marker image and the second reference marker image.

16. The bidirectional off-axis alignment deviation measurement system as claimed in any one of claims 12 to 14, wherein the target alignment unit shares a first reference mark with one or more other alignment units on the sample under test, and / or the target alignment unit shares a second reference mark with one or more other alignment units on the sample under test.

17. The bidirectional off-axis alignment deviation measurement system as claimed in any one of claims 12 to 14, wherein the first reference mark and the second reference mark are both located in the lower layer material of the target alignment unit.

18. The bidirectional off-axis alignment deviation measurement system as claimed in any one of claims 12 to 14, wherein the first reference mark is located in the first alignment unit of the sample under test, and the second reference mark is located in the second alignment unit of the sample under test.

19. The bidirectional off-axis alignment deviation measurement system as claimed in claim 18, wherein the first alignment unit, the second alignment unit, and the target alignment unit are all located in the same layer of the sample to be tested.

20. The bidirectional off-axis alignment deviation measurement system as claimed in any one of claims 12 to 14, wherein the target alignment unit is a first wafer or a diced wafer, and the underlying material of the target alignment unit is a second wafer.

21. The bidirectional off-axis alignment deviation measurement system as claimed in any one of claims 12 to 14, wherein the imaging device is specifically used to: acquire a first target mark image, a first reference mark image, a second target mark image, and a second reference mark image of the target mark by adjusting the relative displacement between the optical axis of the imaging device and the sample under test in the X-axis or Y-axis; the computing device is specifically used to: calculate the X-axis alignment deviation of the target alignment unit in the sample under test based on the first target mark image and the first reference mark image; and calculate the Y-axis alignment deviation of the target alignment unit in the sample under test based on the second target mark image and the second reference mark image.

22. An off-axis mark, comprising: Target marker, first reference marker, and second reference marker; the target marker is located in the target alignment unit of the sample to be tested; The Y-axis distance between the first reference mark and the target mark is greater than the Y-axis distance between the second reference mark and the target mark, and the X-axis distance between the second reference mark and the target mark is greater than the X-axis distance between the first reference mark and the target mark.

23. The off-axis mark as described in claim 22, wherein the target mark includes a first sub-target mark and a second sub-target mark; wherein the first sub-target mark is used in pairs with the first reference mark; and the second sub-target mark is used in pairs with the second reference mark.

24. The off-axis mark as claimed in claim 22, wherein the first reference mark is shared by the target alignment unit and one or more other alignment units on the test sample; and / or, the second reference mark is shared by the target alignment unit and one or more other alignment units on the test sample.

25. The off-axis mark as described in any one of claims 22 to 24, wherein, Both the first reference mark and the second reference mark are located in the lower layer material of the target alignment unit.

26. The off-axis mark as claimed in claim 22, wherein the first reference mark is located in a first alignment cell of the sample to be tested, and the second reference mark is located in a second alignment cell of the sample to be tested.

27. The off-axis mark as described in claim 22, wherein the first reference mark and the second reference mark are located in the same other alignment unit of the sample under test.

28. The off-axis mark as described in claim 26, wherein the first alignment unit, the second alignment unit, and the target alignment unit are all located in the same layer of the sample to be tested.

29. The off-axis marker as claimed in claim 22, wherein the first reference marker is located on another alignment unit on the test sample, and the second reference marker is located on the underlying material of the target alignment unit; or, the second reference marker is located on another alignment unit on the test sample, and the first reference marker is located on the underlying material of the target alignment unit.

30. An off-axis marker as described in claim 22 or 29, wherein the target alignment unit is a first wafer or a diced wafer, and the underlying material of the target alignment unit is a second wafer.

31. The off-axis mark as described in claim 22, wherein the off-axis mark is used in photolithography to align the target alignment unit with the preceding layer material; the target alignment unit is a photoresist layer, and the preceding layer material is a material formed in the sample under test prior to the photoresist layer.

32. The off-axis mark as claimed in claim 22, wherein the target mark is one or more combinations of the following mark types: square, box, or strip; the first reference mark is one or more combinations of the following mark types: square, box, or strip; and the second reference mark is one or more combinations of the following mark types: square, box, or strip.

33. The off-axis mark as described in claim 32, wherein the target mark, the first reference mark, and the second reference mark have the following characteristics: they are identical in shape and at least two are different in size; or, they are identical in shape and the same in size; or, two marks with the same shape are identical in shape and the two marks with the same shape are the same in size or different in size; or, they are all different in shape.

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