An Integrated Model for Adjustment of Process Parameters to Recover Throughput Shortage in Semiconductor Assembly: A Case Study.

Purpose: Existing productivity improvements activities such as inventory buffer, overall equipment effectiveness (OEE) and total productive maintenance (TPM) do not associate the throughput shortage with the process parameters. The paper aims to develop and validate an integrated model to recover the throughput shortage through adjustment of process parameters in a semiconductor assembly setting. Design/methodology/approach: The mathematical model of planned throughput as a function of process parameters in an integrated multiple-process line is developed. When the actual throughput does not meet the planned throughput, throughput shortage occurs. The planned throughput for the next day is summed with the throughput shortage from the previous day, and mathematical programming is used to search the adjusted values of the process parameters. Findings: The throughput shortage can be restored at the following day with the reconfigured process parameters. If throughput shortage still exists, the additional throughput shortage will be carried forward to the subsequent day of planning where mathematical programming is repeated to search the adjusted values of the process parameters. The proposed optimisation model is essentially a parametric model, where actual data of process parameters are fitted into distribution and is translated into a range of allowable values within the 95% confidence interval. Research limitations/implications: The process parameters subject to adjustment in this model are the cycle time of Die Attach, Wire Bond and Pre-Cap Inspection. Downtime and setup time are not subjected to adjustments because these parameters require more extensive efforts to be changed. Practical implications: The mathematical programming computes adjusted values of process parameters to restore the throughput shortage, where it quantitatively correlates the process parameters and throughput shortage, rather than the conventional method of production improvement activities that do not quantitatively correlate with the throughput shortage. Originality/value: The research addresses the adjustment of process parameters to recover the throughput shortage in integrated multiple-process line. [ABSTRACT FROM AUTHOR]