Modeling and Development of Polishing Processes

R. B. Mindek, Jr.
Automated Production Technology Division
Manufacturing Engineering Laboratory
National Institute of Standards and Technology
Gaithersburg, MD  20899

Lapping and polishing have a long history and are probably the oldest known manufacturing professions [1].  They are considered abrasive processes and are used to produce surface finishes and profiles of extreme precision, and are still today critical to the successful manufacture of many modern products, including optical lenses, metallic bearing surfaces, automotive components, gages, semi-conductor substrates and printed circuit boards.  Despite both past and more recent work investigating the relative influence of process parameters [1-9], polishing processes are not well understood, being still highly dependent on the skill, experience and intuition of individual craftsmen.  Successful automation of polishing processes will require this intuitive information to be captured in quantitative polishing process models, which would have significant impact on a number of important industries including optical and electronics manufacturing.  This work addresses the need for a better understanding of polishing processes by further developing a test apparatus known as the Rapid Renewable Lap Mindek-fig01.jpg , which currently has a patent pending [1,2].  Although recent work on this apparatus has led to new insights and some fundamental modeling of process performance trends for different lapping processes, additional work is being conducted to: (1) improve the existing models; (2) define their limits of validity; and (3) broaden the scope of the work to include additional types of lapping and polishing such as chemo-mechanical polishing.  This broadened scope will require the application of disciplines believed to influence polishing processes which heretofore have not been considered.  Namely, the influences of fluid mechanical aspects such as slurry film thickness and flow field distributions Mindek-fig02.jpg , together with pad geometry effects, and their potential interactions with the already broadly considered topic of tribology (abrasive processes).

Note:  Others working on this project include Dr. Chris J. Evans (NIST/APTD/Mentor) and Dr. Ed W. Paul (Visiting Professor, Stockton College).

[1] Evans, C.J., Parks, R.E., Roderick, D.J., McGlauflin, M.L., Rapidly Renewable Lap:  Theory and Practice, Annals of CIRP, Vol. 47/1, pp. 239-244.
[2] Parks, R.E., Evans, C.J., Roderick, D.J., Dagata, J., Applications of the Rapidly Renewable Lap, Proc. SPIE, Vol. 3134, 1997.
[3] Levert, J., Baker, R., Mess, F., Danyluk, S., Salant, R., Cook, L., In-Situ Slurry Film Measurements for Chemical-Mechanical Polishing, Proc. of ASPE,
    v.14,1996, pp.80-85.
[4] Dwyer-Joyce, R.S., Sayles, R.S., Ioannides, E., An Investigation Into the Mechanisms of Closed Three-Body Abrasive Wear, Wear, Vol. 175, 1994, pp.
[5] Moore, M.A., A Review of Two-Body Abrasive Wear, Wear, Vol. 27, 1974, pp. 1-17.
[6] Burwell, J.T., Jr., Survey of Possible Wear Mechanisms, Wear, v.1,1958, pp. 119-141.
[7] Hocheng, H., Tsai, H.Y., An Analytical Aspect of the Preston Equation, Proc. of the ASME, Manf. and Science Div., MED-Vol. 8, 1998, pp. 33-36.
[8] Bhagavat, M., Yang, F., Kao, I., Elasto-Plastic Finite Element Analysis of Indentations in Free Abrasive Machining, Proc. of the ASME, Manf. and Science
    Div., MED-Vol. 8, 1998, pp. 819-824.
[9] Twyman, F., Prism and Lens Making, Adam Hilger Ltd., London, 1942.