Method and apparatus for chemical mechanical polishing
View Patent ↗A chemical mechanical polishing apparatus prevents scratches caused by a direct friction between a polishing pad and a wafer. The apparatus includes a polishing pad, in which grooves are regularly formed, for generating a dynamic pressure by rotation; a polishing table to which the polishing pad is adhered; a wafer provided at a predetermined interval from the polishing pad; a polishing head, on which the wafer is mounted, for driving the wafer; and a slurry supplier for providing slurry to a surface of the polishing pad.
1. An apparatus for chemically mechanically polishing a mounted substrate comprising:
a polishing pad having herring-bone shaped grooves formed so as to generate a dynamic pressure by rotation of the pad;
a polishing table to which the pad is adhered;
a polishing head moveably positioning the substrate at a first predetermined distance from the pad, the first distance being large enough such that the substrate does not directly contact the pad; and
a slurry supplier providing slurry to a surface of the pad.
2. The apparatus of claim 1 , further comprising a polishing conditioner provided at a second predetermined distance from the pad.
3. The apparatus of claim 1 , wherein the pad comprises a polishing pad having grooves formed so as to maintain the substrate at the predetermined first distance from the polishing pad by the dynamic pressure.
4. The apparatus of claim 1 , wherein the grooves comprise a portion bent in a predetermined direction.
5. The apparatus of claim 1 , wherein the pad comprises a polishing pad rotatable in a direction opposite to the predetermined direction.
6. The apparatus of claim 1 , wherein the grooves have a width ratio Lp/L between 0.22 and 0.5.
7. The apparatus of claim 1 , wherein the grooves have a bent angle β between 22° and 32°.
8. The apparatus of claim 1 , wherein the grooves have a depth D between 50 μm and 410 μm.
9. The apparatus of claim 1 , wherein the grooves have a vertical length γ between 0.5 mm and 4 mm.
10. The apparatus of claim 1 , wherein the head comprises a head which oscillates and rotates the substrate.
11. A chemical mechanical polishing apparatus comprising:
a rotatable polishing pad, having grooves formed in a herringbone structure and having a bent portion bent in a predetermined direction such that a rising dynamic pressure is generated when the pad is rotated;
a polishing table to which the polishing pad is adhered;
a polishing head moveably supporting a mounted wafer such that the wafer is maintained at a predetermined first distance from the pad by the pressure, the first distance being large enough such that the substrate does not directly contact the pad; and
a slurry supplier for providing slurry to a surface of the polishing pad.
12. The chemical mechanical polishing apparatus of claim 11 , further comprising a polishing conditioner provided at a predetermined second distance from the polishing pad.
13. The chemical mechanical polishing apparatus of claim 11 , wherein the pad comprises a polishing pad rotatable in a direction perpendicular to the predetermined direction.
14. The chemical mechanical polishing apparatus of claim 11 , wherein the grooves have a groove width ratio Lp/L between 0.22 and 0.5, a bent angle β between 22° and 32°, a groove depth D between 50 μm and 410 μm, and a vertical length γ between 0.5 mm and 4 mm.
15. The chemical mechanical polishing apparatus of claim 11 , wherein the polishing head comprises a head which oscillatingly moves a mounted wafer in a direction perpendicular to the rotation direction of the polishing pad.
16. A method for chemically mechanically polishing a substrate, comprising:
adhering a polishing pad to a polishing table, the pad having grooves which generate a dynamic pressure when rotated;
mounting the substrate on a polishing head;
providing slurry to a surface of the pad; and
rotating the pad to generate a dynamic pressure sufficient to maintain the substrate at a predetermined first distance from the pad, the first distance being large enough such that the substrate does not directly contact the pad.
17. The method of claim 16 , further comprising:
operating a polishing conditioner at a second predetermined distance from the pad.
18. The method of claim 16 , wherein adhering the pad comprises:
adhering a pad having grooves with a herringbone-shaped structure having a bent portion.
19. The method of claim 18 , wherein rotating the pad further comprises:
rotating the pad in a direction perpendicular to the direction of the bent portion of the herringbone-shaped grooves.
20. The method of claim 18 , wherein the herringbone-shaped grooves have a groove width ration Lp/L between 0.22 and 0.5.
21. The method of claim 18 , wherein the herringbone-shaped grooves have a bent angle β between 22° and 32°.
22. The method of claim 18 , wherein the herringbone-shaped grooves have a groove depth D between 50 μm and 410 μm.
23. The method of claim 18 , wherein the herringbone-shaped grooves have a vertical length γ between 0.5 mm and 4 mm.
24. The method of claim 16 , further comprising:
oscillating and rotating the substrate using the polishing head.