Application of single asperity abrasion process for surface micro-machining

Basic understanding of asperity interaction with the counter surface during an abrasive wear process may be utilized to develop a precision machining process. This concept is implemented in this work using a diamond tip as the cutting tool and coated silicon wafer and metal specimens as the workpiece. The tip acts as a single asperity abrading the counter surface during the contact sliding motion. A precision machine based on computer numerical control was designed and built to perform such an abrasion process. The machine was instrumented to monitor the normal and frictional forces during the abrasion process. By optimizing the contact and sliding conditions the workpiece material could be removed at the micrometer scale. This technique was successfully developed to machine SiO2 resist material coated on silicon wafer. Subsequent processing of the silicon by chemical etching produced micro-grooves that could otherwise be fabricated only by more complicated and capital intensive photolithographic methods. Also, in a different process, by feeding the diamond tip in the direction perpendicular to the sliding direction after each path, 100 x 100 mum square pockets with recess steps of 2 mum could be successfully fabricated on a brass surface. This intricate pattern can be used as a tool for molding micro-parts. This work demonstrates the capability of single asperity abrasion process in surface micro-machining. (C) 2001 Elsevier Science B.V. All rights reserved.