<title>SEM-based ADC evaluation and integration in an advanced process fab</title>

Abstract

This paper summarizes the work completed as part of the Equipment Evaluation Program (EEP) for the Applied Materials SEMVision cX at Texas Instruments KFAB facility. This tool employs real time Automatic Defect Classification (ADC) software in conjunction with an Automatic Defect Redetection (ADR) capability. The SEMVision cX utilizes a unique imaging system that employs multiple detectors to create several perspectives of the defect image. These perspectives enhance certain features of the defect that facilitate Automatic Defect Redetection of all defect types, and enable a rule-based ADC system. This tool was designed to meet the requirements of an advanced CMOS fab, which requires increased imaging resolution to resolve the ever-smaller defects that can cause yield loss. This evaluation program was begun to accomplish three objectives: 1) To evaluate the tool for automatic defect classification on advanced CMOS technology. 2) To increase speed/throughput/resolution of defect review. 3) To increase the accuracy of defect classification with the use of ADC. Of great importance for TI's advanced wafer fabs is the need for a defect review SEM that also has the capability of ADC to improve defect classification accuracy and also to improve queue time in the Yield Enhancement (YE) operations. In addition to this, the need to be fully integrated into the fab DMS (Defect Management System) and TI's Automation system is crucial for automating many routine functions for the YE group. With the YE group personnel freed from the manv tedious data management tasks, they can work on yield issues in real-time. The SEM Vision cX differs from usual fab SEM's in that it employs MPSI (Multiple Perspective Imaging) which is three detectors, one at normal incidence to the wafer and two on either side of normal from the electron beam. This configuration of detectors gives added information to the ADC system, provides for robust redetection, and establishes a paradigm for automatic defect classification based on topography and material perspectives. The SEMVision cX met all of the requirements during the evaluation with the exception of the tilt and rotate capabilities. There were two areas that were involved in this evaluation, one was for the defect review SEM itself and the other was for Automatic Defect Classification (ADC). Also included in this evaluation was the integration of the SEMVision cX into TI's DMS (Defect Management System) and Automation networks.