Research On Optical Multi-Channel Surface Detecting System

With the development of semiconductor manufacturing processes, wafers and thin films are widely used in optoelectronic and microelectronic devices. The surface defects of wafers and thin films become the primary factors which have effects on devices performances. Therefore, it is necessary for manufacturers to detect these defects in real time and online. Because of the diversity of these defects, several instruments must be used to detect them. This can cause poor efficiency and high cost. So how to detect many defects with one instrument is concerned by many manufacturers.In this thesis, an optical multi-channel surface detecting system (OMSDS) is designed. The system combines the functions of reflectometers, scatterometers, phase shift detectors and optical profilometers. Experiments'results show that the system can measure the majority of defects of wafers and thin films. Finally, suggestions are also made to the further work. The main contents can be summarized as follows:(1)Several optical detecting methods are summarized and reorganized. The OMSDS and its basic optical layout are designed with the help of several conventional optical theory used for surface detecting. The experiment indicates that our design is feasible.(2)The function definition of the image gathering subsystem is made. According to the requirement of the image gathering subsystem and the characteristic of CMOS image sensor, the schematic circuit diagram (SCD) of the images gathering subsystem is designed. The printed circuit board is manufactured to verify the SCD of the images gathering subsystem. The image gathering of the OMSDS is carried out.(3)The function definition of the data transmission subsystem is made. The SCD of the data transmission subsystem is designed based on the requirement of the data transmission subsystem and the characteristic of USB interface. The USB firmware and its driver are programmed, which are verified by a development board of USB 2.0. The data transmission of the OMSDS is carred out.