Tribology dimensional

Runnels and Eyman [41] report a tribological analysis of CMP in which a fluid-flow-induced stress distribution across the entire wafer surface is examined. Fundamentally, the model seeks to determine if hydroplaning of the wafer occurs by consideration of the fluid film between wafer and pad, in this case on a wafer scale. The thickness of the (slurry) fluid film is a key parameter, and depends on wafer curvature, slurry viscosity, and rotation speed. The traditional Preston equation R = KPV, where R is removal rate, P is pressure, and V is relative velocity, is modified to R = k ar, where a and T are the magnitudes of normal and shear stress, respectively. Fluid mechanic calculations are undertaken to determine contributions to these stresses based on how the slurry flows macroscopically, and how pressure is distributed across the entire wafer. Navier-Stokes equations for incompressible Newtonian flow (constant viscosity) are solved on a three-dimensional mesh ... 

Heat. Heat is the third major component of tribological effects, easily examined by rubbing one s hands together briskly, first dry and then wet. The heat produced through friction can be intense, leading to dimensional changes that in turn aggravate both friction and abrasion and perhaps lead to the failure of the mechanism. 

Dimensional criterion. In tribological contact processes both lateral and depth dimensions are important, the former because of the size and shape of wear debris and the latter because of the presence of thin films. It is therefore vital to match the characteristics of a technique to the dimensions of the analysis. 

In engine oil circulation systems glass fibre-reinforced PES is particularly suitable, since the polymer matrix ensures the necessary thermal and dimensional stability when in contact with hot engine oil. In addition there are the outstanding mechanical and tribological characteristics up to high temperatures. 

Toumerie B., Danos J.C., Fr6ne J. - Three-dimensional modeling of THD lubrication in face-seals , ASME Journal of Tribology, Vol. 123, pp. 196-204,2001. 

Kweh, C. C., Evans, H. P., and Sindle, R. W., 1989, Micro-Elastohydrodynamic Lubrication of An Elliptical Contact with Transverse and 3-Dimensional Roughness, ASME Journal of Tribology, Vol. Ill, pp.577-584. 

Ai, X., Cheng, H.S., and Zheng, L., 1993, "A Transient Model for Micro-Elastohydrodynamic Lubrication with Three Dimensional Irregularities, ASME Journal of Tribology, Vol.115, pp.102-110. 

Kweh, C C, Evans, H P, and Snidle, R W, 1989, "Microelastohydrodynamic lubrication of an elliptical contact with transverse and three-dimensional roughness", J. of Tribology, Trans ASME, Vol lll,pp 577-584. 

Dimensional Rough Surfaces, ASME Journal of Tribology, Vol.119, pp.375-384. 

Ai, X. L., 1998, Effect of three-dimensional random surface roughness on contact fatigue , ASME Journal of Tribology. Vol. 120, pp. 159-164. 

This article has investigated the potential of cross-linked polyamides for tribological applications. Results have shown a significant influence of the structural properties decrease in crystallinity, cross-linking particularly within quasi-amorphous or less crystalline ranges and the formation of a three-dimensional network. This shows up in the macroscopic material behavior increased insolubility, increased elastic modulus, particularly in the glass transition region, increased stiffness, brittleness, reduced creep and an increase in surface polarity. 

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