Chemical mechanical polishing apparatus and method
The present disclosure describes an apparatus and a method to detect a polishing pad profile during a polish process and adjust the polishing process based on the detected profile. The apparatus can include a polishing pad configured to polishing a substrate, a substrate carrier configured to hold the substrate against the polishing pad, and a detection module configured to detect a profile of the polishing pad. The detection module can include a probe configured to measure a thickness of one or more areas on the polishing pad, and a beam configured to support the probe, where the probe can be further configured to move along the beam.
1. A method for operating a polishing system, comprising:
determining a profile of one or more areas of a polishing pad of a polishing system during a polishing process;
comparing the profile to a reference profile, wherein the reference profile is a simulated profile of the polishing pad; and
adjusting one or more parameters of the polishing process based on the comparison.
2. The method of claim 1 , wherein determining the profile comprises collecting thickness data associated with the one or more areas of the polishing pad.
3. The method of claim 1 , wherein determining the profile comprises measuring a thickness of one or more areas of the polishing pad while the polishing pad is rotating.
4. The method of claim 1 , wherein the simulated profile is generated by a mathematical process, a machine learning process, a big data mining process, or a neural network process.
5. The method of claim 1 , wherein the polishing process comprises a substrate polishing process or a conditioning process.
6. The method of claim 1 , wherein adjusting the one or more parameters comprises adjusting at least one of a rotation speed of the polishing pad, a substrate carrier of the polishing system, a rotation speed of the substrate carrier, a pressure applied by the substrate carrier, a flow rate of a slurry supply of the polishing system, a location of the slurry supply, a location of a conditioner of the polishing system, a rotation speed of the conditioner, and a pressure applied by the conditioner.
7. A method, comprising:
scanning a surface of a polishing pad to determine a surface profile of the polishing pad;
performing a comparison between the surface profile and a reference profile; and
in response to a region of the surface of the polishing pad being determined as heavily-worn according to the comparison, adjusting a location of a wafer being polished on the polishing pad by moving the wafer away from the region.
8. The method of claim 7 , wherein scanning the surface of the polishing pad comprises moving an optical transmitter and an optical receiver across the surface of the polishing pad.
9. The method of claim 8 , wherein scanning the surface of the polishing pad further comprises:
transmitting, using the optical transmitter, a first optical signal towards the surface of the polishing pad; and
receiving, using the optical receiver, a second optical signal reflected by the surface of the polishing pad.
10. The method of claim 9 , wherein scanning the surface of the polishing pad further comprises detecting a phase difference between the first and second optical signals.
11. The method of claim 7 , wherein scanning the surface of the polishing pad comprises moving an acoustic device across the surface of the polishing pad.
12. The method of claim 11 , wherein scanning the surface of the polishing pad further comprises:
transmitting, using the acoustic device, a first acoustic signal towards the surface of the polishing pad; and
receiving, using the acoustic device, a second acoustic signal reflected by the surface of the polishing pad.
13. The method of claim 12 , wherein scanning the surface of the polishing pad further comprises determining a distance between the surface of the polishing pad and the acoustic device.
14. The method of claim 7 , further comprising generating a simulated profile as the reference profile by predicting a projected wear of the polishing pad.
15. A method, comprising:
performing a polishing process on a wafer by pressing the wafer against a surface of a polishing pad and rotating the wafer;
measuring a surface profile of the polishing pad while polishing the wafer;
dispensing a slurry on the polishing pad;
determining a condition of the surface of the polishing pad; and
adjusting, based on the condition of the polishing pad, a location on the polishing pad to dispense the slurry.
16. The method of claim 15 , wherein measuring the surface profile comprises measuring a thickness, a surface roughness, or a surface contour of the surface of the polishing pad.
17. The method of claim 15 , wherein determining the condition of the surface of the polishing pad comprises comparing the surface profile to a reference profile of the surface of the polishing pad.
18. The method of claim 15 , wherein the adjusting further comprises adjusting a rotation speed of the wafer or a pressure of the wafer applied against the surface of the polishing pad.
19. The method of claim 15 , further comprising:
conditioning the polishing pad by rotating a conditioner pressed against the surface of the polishing pad; and
adjusting, based on the condition of the polishing pad, a rotation speed of the conditioner or a pressure of the conditioner applied against the surface of the polishing pad.
20. The method of claim 15 , further comprising adjusting, based on the condition of the polishing pad, a flow rate to dispense the slurry.