Polishing pad detection device and polishing pad detection method

Abstract

A polishing pad detection device is used in a chemical mechanical polishing system. The chemical mechanical polishing system has a polishing pad. The polishing pad detection device includes: a computing unit; and a first contour sensing unit for emitting a first laser beam to irradiate the polishing pad and form a first light stripe. The first contour sensing unit obtains first distance information based on the first light stripe. The computing unit determines the state of the polishing pad based on the first distance information.

Claims

1. An abrasive pad detection device (1) is used in a chemical mechanical polishing system having an abrasive pad (9), the abrasive pad detection device (1) comprising: One arithmetic unit (111); A first contour sensing unit (16) is electrically connected to the arithmetic unit (111); and a storage unit (112) is electrically connected to the arithmetic unit (111). The storage unit (112) includes a preset operation command (1121). The arithmetic unit (111) controls the following according to the preset operation command (1121): Before the polishing pad (9) is polished, when the chemical mechanical polishing system controls the polishing pad (9) to rotate, the first contour sensing unit (16) emits a first laser beam (161) to irradiate the polishing pad (9) and form a first light strip (162). The first light strip (162) spans the plurality of grooves (9g) of the polishing pad (9); Based on the first light strip (162), a plurality of reference distance information (Hb) is obtained at a fixed frequency. When one of the reference distance information (Hb) is substantially the same as the other of the reference distance information (Hb), the number of the reference distance information (Hb) is recorded; after the polishing pad (9) is polished, it is determined whether the polishing pad (9) has rotated an integer number of revolutions based on the number of the reference distance information (Hb); when the polishing pad (9) has rotated an integer number of revolutions, the first contour sensing unit (16) emits the first laser beam (161) to irradiate the polishing pad (9) and form the first light stripe (162); a distance distribution information (Hd) between the first light stripe (162) of the polishing pad (9) and the first contour sensing unit (16) is obtained based on the first light stripe (162); and the state of the polishing pad (9) is determined based on the distance distribution information (Hd) and one or the other of the reference distance information (Hb).

2. The abrasive pad detection device (1) as claimed in claim 1, wherein the first light strip (162) covers a radius (R) of the abrasive pad (9).

3. The abrasive pad detection device (1) as claimed in claim 2, wherein the length of the first light strip (162) is equal to the radius (R) of the abrasive pad (9).

4. The abrasive pad detection device (1) as claimed in claim 1, further comprising: A second contour sensing unit (17) is electrically connected to the computing unit (111). The second contour sensing unit (17) emits a second laser beam (171) to irradiate the polishing pad (9) and form a second light stripe (172). The second contour sensing unit (17) obtains a second distance information (H2) based on the second light stripe (172). The computing unit (111) determines the state of the polishing pad (9) based on one or the other of the distance distribution information (Hd) and the reference distance information (Hb) and the second distance information (H2).

5. The abrasive pad detection device (1) as claimed in claim 4, wherein the first light strip (162) and the second light strip (172) form a continuous light strip (LB) that covers a radius (R) of the abrasive pad (9).

6. The abrasive pad detection device (1) as claimed in claim 5, wherein the length of the continuous light strip (LB) is equal to the radius (R) of the abrasive pad (9).

7. The abrasive pad detection device (1) as claimed in claim 1, further comprising: A first light source (121) is electrically connected to the computing unit (111), the first light source (121) emits a light ray (L), the light ray (L) illuminates the polishing pad (9); and a first camera (131) is electrically connected to the computing unit (111), the first camera (131) captures the polishing pad (9) and generates a first image information (311); wherein, the computing unit (111) obtains a first gray level difference distribution (331) based on the first image information (311), and determines the state of the polishing pad (9) based on one or the other of the first gray level difference distribution (331), the distance distribution information (Hd) and the reference distance information (Hb).

8. A method for testing an abrasive pad (9) in a chemical mechanical polishing system, the method comprising: Before grinding the polishing pad (9), the chemical mechanical polishing system controls the polishing pad (9) to rotate, and uses a first laser beam (161) to irradiate the polishing pad (9) and form a first light strip (162), which spans the plurality of grooves (9g) of the polishing pad (9); Based on the first light strip (162), a plurality of reference distance information (Hb) is obtained at a fixed frequency; When one of the reference distance information (Hb) is substantially the same as the other of the reference distance information (Hb), the number of reference distance information (Hb) obtained is recorded; After the polishing pad (9) is ground, it is determined whether the polishing pad (9) has rotated an integer number of revolutions based on the number of reference distance information (Hb); When the polishing pad (9) has rotated an integer number of revolutions, the first laser beam (161) is used to irradiate the polishing pad (9) and form the first light strip (162); Based on the first light strip (162), a distance distribution information (Hd) between the first light strip (162) of the polishing pad (9) and a first contour sensing unit (16) is obtained; and the state of the polishing pad (9) is determined based on one or the other of the distance distribution information (Hd) and the reference distance information (Hb).

9. The polishing pad detection method as described in claim 8, wherein determining the state of the polishing pad (9) based on the distance distribution information (Hd) further includes: When the absolute value of the difference between a first distance information (H1) of the distance distribution information (Hd) and one or the other of the reference distance information (Hb) is greater than a distance threshold, the first distance information (H1) is defined as a bad distance information.

10. The method for testing abrasive pads as described in claim 8 further includes: The polishing pad (9) is illuminated with a light beam (L); a first image information (311) of the polishing pad (9) is obtained; a first line segment (321) is obtained in the first image information (311), the first line segment (321) spanning the plurality of grooves (9g) of the polishing pad (9); and a first gray level difference distribution (331) in the first line segment (321) is obtained; the state of the polishing pad (9) is determined based on one or the other of the distance distribution information (Hd) and the reference distance information (Hb), further comprising: determining the state of the polishing pad (9) based on one or the other of the first gray level difference distribution (331) and the distance distribution information (Hd) and the reference distance information (Hb).

11. The abrasive pad detection method as claimed in claim 10, wherein the first line segment (321) is located at the corresponding position of the first light stripe (162) in the first image information (311).

12. The method for testing abrasive pads as described in claim 10, further comprising: A second line segment (322) is obtained from the first image information (311), the second line segment (322) spanning the plurality of grooves (9g) of the abrasive pad (9); a second gray level difference distribution (332) is obtained from the second line segment (322); a plurality of peak values ​​(35) are obtained from the second gray level difference distribution (332); a peak reference value (351) is defined; and the peak values ​​(35) greater than or equal to the peak reference value (351) are defined as the plurality of qualified peak values ​​(352).

13. The abrasive pad testing method as described in claim 12, wherein defining the peak reference value (351) further includes: Calculate an average value of gray level difference peaks (343) based on the first gray level difference distribution (331); and define the peak reference value (351) as the average value of gray level difference peaks (343) multiplied by a factor.

14. The method for testing abrasive pads as described in claim 12, further comprising: In the second grayscale difference distribution (332), a distance (D) is obtained between any two adjacent qualified peak values ​​(352); a distance threshold is defined; and when one of the distances (D) is greater than the distance threshold, the second grayscale difference distribution (332) is defined as an undesirable grayscale difference distribution (36).

15. The method for testing abrasive pads as described in claim 10, further comprising: A first grayscale difference average value (341) is calculated based on the first grayscale difference distribution (331); after a time interval of obtaining the first image information (311) of the polishing pad (9), a second image information (312) of the polishing pad (9) is obtained; a third line segment (323) is obtained in the second image information (312), the third line segment (323) spans the plurality of grooves (9g) of the polishing pad (9); a third grayscale difference distribution (333) is obtained in the third line segment (323); a second grayscale difference average value (342) is calculated based on the third grayscale difference distribution (333); and the state of the polishing pad (9) is determined based on the first grayscale difference average value (341) and the second grayscale difference average value (342).

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