厦门大学2011高等代数.pdf

_____________________________________________________________________________________________ 1 The Design of a 3-D Surface Geometry Acquisition System for Highly Irregular Shaped Objects: with Application to CZ Semiconductor Manufacture Vivek A. Sujan and Steven Dubowsky Department of Mechanical Engineering Massachusetts Institute of Technology Cambridge, MA 02139 Abstract A Robotic System is being developed to automate the crucible packing process in CZ semiconductor wafer production. It requires the delicate manipulation and packing of highly irregular polycrystalline silicon nuggets, into a fragile fused silica crucible. For this application, a dual optical 3-D surface geometry measuring system that uses active laser triangulation has been developed and essfully tested. One part of the system measures the geometry profile of a nugget being packed and the other the profile of the nuggets already in the crucible. A resolution of 1mm with 15 KHz sampling frequency is achieved. Data from the system is used by a packing algorithm to determine optimal nugget placement. The system is shown to achieve high production rates, required precision and cost effectiveness. 1 Introduction The requirements for growing large single device-grade semiconductor crystals are very stringent. Extraordinary low impurity levels, on the order of 1 part in 10 billion, are required. Such low c