Characteristics of High Rotational Speed Polishing with Oscillation Speed Control

Abstract:

The miniaturization of semiconductor devices is advancing rapidly. The requirement for wafer flatness is becoming increasingly stringent as the use of shorter wavelengths in the latest laser lithography results in a smaller focusing depth of field. In our research, a flatness of 0.1 µm has been achieved over an entire 12" wafer surface by planarization with oscillation speed control type polishing. However, in addition it is necessary to increase the removal rate in order to reduce the polishing time. Although high rotational speed polishing is a solution to meet this requirement, the polishing characteristics change with the rotational conditions. Using a simulation program, we calculated that the stock removal saturates as the rotational speeds of the wafer and polishing pad are increased beyond a certain point. Also, experimental results showed that at high rotational speeds actual stock removal is significantly less than that indicated by the simulation, and that too much slurry causes unnecessary etching.

• Periodical: Key Engineering Materials (Volumes 291-292)
• Pages: 355-358
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.291-292.355
• Online since: August 2005
• Authors: Kenichiro Yoshitomi, Atsunobu Une, Masaaki Mochida
• Keywords: CMP, Oscillation Speed Control, Polishing Simulation, Slurry Flow Rate, Stock Removal

References

[1] A. Une at al., Influence of Wafer Chucking on Focus Margin for Resolving Fine Patterns in Optical Lithography, Microelectronic Engineering Vol. 53, (2000), pp.137-140.

DOI: 10.1016/s0167-9317(00)00281-1

[2] T. Senga at al., Profile Control by the smart simulator in partical Polishing CMP, CMP-MIC Conference, (2003), pp.200-204.

[3] K. Yoshitomi, A. Une and M. Mochida, Highly Efficient CMP Planarization Using a Ring Polisher with Oscillation Speed Control, Proceedings of ISAAT2001, (2001).

0.

4.

8 -150 -100 -50 0 50 100 150 Distance from wafer center mm Stock removal µm.

0.

4.

8 -150 -100 -50 0 50 100 150 Distance from wafer center mm Stock removal µm.

0.

4.

8 -150 -100 -50 0 50 100 150 Distance from wafer center mm Stock removal µm Experimental Simulated Experimental Simulated Experimental Simulated Fig. 7. Stock removal for different slurry rates for oscillation (a) Oscillation range of 20 - 40 mm Fig. 8. Stock removal when the wafer and the pad rotated at 300 rpm and -300 rpm respectively, and slurry rate was 50 ml/min (b) Oscillation range of 100 - 120 mm.

DOI: 10.31857/s0002-33372019358-70-10125

0.

4.

8 -150 -100 -50 0 50 100 150 Distance from wafer center mm Stock removal µm.

0.

4.

8 -150 -100 -50 0 50 100 150 Distance from wafer center mm Stock removal µm.

0.

4.

8 -150 -100 -50 0 50 100 150 Distance from wafer center mm Stock removal µm 50ml/min 100ml/min Experimental Simulated Experimental Simulated Simulated at 100 ml/min Wafer : 100 rpm, Pad : -300 rpm.

[4] K. Yoshitomi, A. Une and M. Mochida, Inprovement simulation accuracy in precision CMP with Oscillation Speed Control, Advances in Abrasive Technology 6, (2003), pp.429-432.

DOI: 10.4028/www.scientific.net/kem.257-258.429