Classification and Size Estimation of Wafer Defects by Using Scattered Light Distribution

Abstract

SUMMARY Usually, wafer inspection is a two‐step process. The first step, which is very important, consists of detection of defects on the wafer. The second step classification of the detected defects, which is done after defect detection as necessary. Recently, it has become necessary to perform simultaneous detection and classification of wafer defects in order to reduce the wafer inspection time while maintaining high resolution of inspection. Optical wafer inspection is the most effective method for detecting and classifying defects and estimating their size in a short time. In this method, the scattered light distribution is compared with a database of previous scattered light distributions and pattern matching is used to classify defects and estimate their size. Therefore, to achieve optical wafer inspection based on scattered light distribution, it is necessary to gather scattered light distribution data for many samples of various kinds. The first aim of this study is to develop a defect classification and size estimation method utilizing the scattered light distribution. We propose a method of classifying defects on wafers and estimating their size. The proposed method is based on pattern matching utilizing a parametric eigenspace. The second aim of the paper is to validate the proposed method by applying it to scattered light distribution samples. The light scattering distribution samples were generated by discrete dipole approximation (DDA) simulation. A database of the light scattering distribution is easily created using the simulation.

Development of multi-stage optical variable attenuator system and its control method for wafer inspection system

“…2.1 System overview An overview of the optical wafer inspection system [2][3][4][5][6][7][8][9][10][11] is shown in Fig. 1.…”

“…Various inspection systems have been developed for each semiconductor manufacturing process [1]. Optical inspection systems for unpatterned wafers [2][3][4][5][6][7][8][9][10][11] are used to measure surface defects of silicon wafers as the pre-shipment inspection in wafer manufactures and the acceptance inspection in device manufactures. In order to inspect the entire wafer surface at high speed, this system rotates and moves the wafer to irradiate a laser beam onto the wafer in a spiral shape and detects the scattered light from defects.…”

A Light-Weighted CNN Model for Wafer Structural Defect Detection

“…The images are scaled randomly. The scaling matrix is shown in Formula (12). S is the scaling factor.…”

Structural Design and Simulation of a Multi-Channel and Dual Working Condition Wafer Defect Inspection Prototype

“…Defects such as pits, scratches, and particles exist on the surface of wafers [ 1 , 2 ]. These defects have a significant impact on subsequent manufacturing processes and product performance.…”