Intelligent Sampling Decision Scheme Based on the AVM System for Mass Production Applications

Abstract

Wafer inspection plays a significant role in monitoring the quality of wafers production for continuous improvement However it requires measuring tools and additional cycle time to do real metrology which is costly and time-consuming Therefore reducing sampling rate to as low as possible is a high priority to reduce production cost Several sampling methods in the literature were proposed to achieve this goal They utilized real sampling inspections as the representatives for the other related wafers to monitor the whole production process Under the condition of stable manufacturing process virtual metrology (VM) may be applied to monitor the quality of wafers while real metrology is unavailable Therefore the sampling rate may further be reduced with a sampling decision scheme being designed according to reliable VM Two stages of tasks are designed and implemented to construct a generic intelligent sampling decision scheme The first stage is to develop the Static Intelligent Sampling Decision (Static ISD) scheme with static sampling rate and the advanced second stage is to build the Dynamic Intelligent Sampling Decision (Dynamic ISD) scheme with dynamic/automated sampling rate The authors have developed the automatic virtual metrology (AVM) system for various VM applications Therefore this paper focuses on applying various indices of the AVM system to develop both the Static and Dynamic ISD schemes for reducing sampling rate while VM accuracy is still sustained

Date of Award	2014 Sept 23
Original language	English
Supervisor	Fan-Tien Cheng (Supervisor)