Application to Semiconductor Processing

The most widely used pad for dielectric CMP is ICIOOO, a class III material [2]. A micrograph of ICIOOO pad microstructure is given in Fig. 7. A summary of material property data taken from a large volume analysis [18] is given in Table V. 

Property Average Standard deviation (SD) SD/Ave (%) Maximum Minimum Range 

While the results and conclusions are consistent with the asperity contact model discussed earlier, the data does not unambiguously demonstrate the connection to asperity deformation. One of the complicating assumptions in Ref. [14] was that the shear modulus used in the comparison was a composite modulus calculated from the bulk material properties of each component in a two-pad stack. If asperity deformation is a dominant factor, a more appropriate value is the shear modulus of the contacting member. 

Additional insight was obtained from conditioning studies conducted on class IV pads. A pad of the type described in Ref. [3] was prepared from a solid urethane sheet and used in an oxide CMP process. Pad material properties and process conditions employed are given in Tables VI and VII, respectively. 

The polishing rate decay kinetics observed in this experiment are graphically illustrated in Fig. 10. Data fit Eq. (12), yielding R, = 1524A/min and 

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Tsoupras, G. (1996). ICP-MS application to semiconductor processing chemical materials analysis. Analusis 24(9-10), 23. 

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