Implementation of a Fluctuation Smoothing Production Control Policy in IBM&#8217;s 200mm Wafer Fab
Efficient operation of IBM Vermont’s 200mm semiconductor wafer fabrication facility is essential to achieve the objective of transforming the site into a world class foundry manufacturer. To that end, we develop a fluctuation smoothing for the variation of cycle time (FSVCT) production control policy capable of allowing for a diversity of cycle time commitments. The policy directs which lot should next receive processing when a tool becomes available. In the absence of a validated cycle time model for the fabricator, we obtain estimates of achievable cycle time performance in the presence of business constraints on the cycle times of certain lots via a consequence of Little’s law. The mean and variation of cycle time implications for IBM Vermont’s facility are highlighted.
Abstract Some new possibilities of using specular neutron reflection in the study of roughness and interdiffusion in thin-film structures have been proposed and tested (the use of polychromators and supermirrors, direct measurement of the thickness of nonmagnetic interdiffusion layers). A statistical roughness growth law was found to be satisfactory in the interpretation of results, the growth rate being dependent on the materials used, film deposition techniques, etc. The use of ( λ 4 , λ 2 ) -sequences is proposed to increase the sensitivity of the method to the nonmagnetic interdiffusion layer thickness.