Track 1 Session 4

2:20 to 3:20 p.m. Wednesday April 7, 2010

Manufacturing Process Reliability: A Tool That Supplements Six Sigma for Zero Defects

With the steady growth of customer requirements and expectations, the Zero Defect strategy becomes more and more common to manufacturers in different market segments. This surely will be the case when the distance between the supply chain and the final product is long. In contrast to most reliability data, the amount of data processed during manufacturing is rather large. It is therefore important to be able to assess these data down to the parts per million (ppm) level. Previously, this was done by using Statistical Process Control (SPC) and the Six Sigma philosophy. However, in today’s high volume processes, feedback loops based on SPC alone are either too slow or do not show trends when associated quality costs have already increased. In this presentation, the process control philosophy is reviewed and classified within the Zero Defect strategy. Then an enhanced but simple method of combining Weibull analysis with SPC concepts is shown. This method makes it possible to initiate an out-of-control action plan before process variation actually starts to increase quality costs to a large extent.

Key Words: Process Reliability, SPC, PPM Capable SPC Strategy, Weibull Analysis, MLE (Maximum Likelihood Estimation), LSE (Least Square Estimation), Process Defect Density, Tool Defect Density, Zero Defects, fWLR-Monitoring, Raw Data Assessment, Plotting Positions

Andreas Aal

Melexis Microelectronic Integrated Systems

Germany