Methods for enhancing chemical mechanical polishing pad processes
View Patent ↗The present invention discloses a CMP device and methods that are capable of improving CMP processing through incorporation of vibration sources which produce vibrations in a direction substantially parallel to the working surface of the CMP pad. The CMP device includes a CMP pad dresser. Such a method can include steps of vibrating a CMP pad, CMP pad dresser, or wafer in a direction substantially parallel to a working surface of the CMP pad and engaging the CMP pad dresser with a working surface of a CMP pad The results of vibrating the superabrasive particles can provide benefits to both the CMP pad and dresser, according to several aspects disclosed herein.
1. A method of minimizing a drag coefficient on superabrasive particles of a CMP pad dresser during a CMP pad conditioning process, comprising:
rotating a CMP pad dresser in a circular motion relative to a CMP pad;
vibrating the CMP pad in a direction substantially parallel to a working surface of the CMP pad at a frequency of at least about 1 KHz while rotating the CMP pad dresser; and
engaging the CMP pad dresser with the working surface of the CMP pad such that vibration between the CMP pad dresser and the CMP pad occurs in a direction substantially parallel to the working surface of the CMP pad, wherein the vibration reduces frictional forces between the CMP pad dresser and the CMP pad.
2. The method of claim 1 , wherein minimizing drag coefficient creates CMP pad asperities having substantially uniform heights.
3. The method of claim 2 , wherein the uniform asperity height evens workload distribution, thereby extending CMP pad service life.
4. The method of claim 2 , wherein the uniform asperity height promotes uniform polishing of the wafer being polished by the CMP pad.
5. The method of claim 1 , wherein minimizing drag coefficient creates CMP pad troughs having substantially uniform depths.
6. The method of claim 1 , wherein minimizing the drag coefficient minimizes CMP pad asperity size.
7. The method of claim 1 , wherein minimizing the drag coefficient minimizes removal of CMP pad material.
8. The method of claim 1 , wherein minimizing the drag coefficient reduces wear on superabrasive particles.
9. The method of claim 1 , wherein the vibration is in a lateral, circular, elliptical, or random motion substantially parallel to the working surface of the CMP pad.
10. The method of claim 1 , wherein the vibrating is only in a direction parallel to a working surface of the CMP pad.
11. The method of claim 1 , wherein the vibration is controlled by controlling either vibration frequency, amplitude or both.
12. The method of claim 1 , wherein the vibrating is at an ultrasonic frequency.
13. The method of claim 12 , wherein the frequency is an ultrasonic frequency greater than 15 kHz.
14. The method of claim 12 , wherein a temperature measurement of at least a portion of the CMP pad is elevated by at least about 5° C. by the vibrating.
15. The method of claim 1 , wherein a slurry of particles is present on the CMP pad.
16. The method of claim 15 , wherein vibrations disperse particles in the slurry.
17. The method of claim 1 , wherein the vibrating is continuous.
18. The method of claim 1 , wherein the vibrating is diffused.