Run by Run (Generalized SPC) Control of Semiconductor Processes on the Production Floor

摘要

Classical Statistical Process Control states that one should not make process adjustments after each run based on post process measurements. At the other end of the spectrum is real time control which makes process adjustments continuously as the process is running. Most semiconductor processes do not have sensors that allow for real time feedback control. Multiple linear response surface methodology coupled with run by run (Generalized SPC) control has been applied at Delco Electronics to a high volume production epitaxy deposition process.rnThis resulted in nearly a 1.8X improvement in process capability for thickness control. This was achieved by interfacing an IBM compatible 486 computer to Gemini II epi reactors, translating Sun workstation Matlab script code from the Massachusetts Institute of Technology into PC compatible Matlab script code, and combining this with the InTouch man machine interface (MMI) software package from Wonderware, Inc.rnThis paper is a case study of our experience at implementing this on the production floor. We discuss the general nature of the process to show why this methodology is relatively easy to apply. Operator training was simplified, data acquisition capability was added, new enhanced modes of operation were implemented, and enhanced capability for more advanced processes is possible on equipment the did not originally provide these features. We will conclude with observations about how future implementations can be simplified based on our experience.