Shinichi Shinoda

High-quality image processing architecture for facsimiles

A total and coherent image processing architecture for G3/G4/ISDN facsimiles is proposed that features high-quality multi-level processing by means of correlative area scanning and a software-oriented processing architecture. This image processing LSI controller includes a resolution converter and error diffusion halftone processing circuits in 4000 gates. A semi-superfine scanning mode is evaluated, which will be adopted as a new CCITT G3 optional mode.

Focus measurement using SEM image analysis of circuit pattern

We have developed a new focus measurement method based on analyzing SEM images that can help to control a scanner. In advanced semiconductor fabrication, rigorous focus control of the scanner has been required because focus error causes a defect. Therefore, it is essential to ensure focus error are detected at wafer fabrication. In the past, the focus has been measured using test patterns made outside of the chip by optical metrology system. Thus, present focus metrology system can’t measure the focus of an arbitrary point in the chip. The new method enables a highly precise focus measurement of the arbitrary point of the chip based on a focus plane of a reference scanner. The method estimates the focus amount by analyzing side wall shapes of circuit patterns of SEM images. Side wall shapes are quantified using multisliced contours extracted from SEM-images high accuracy. By using this method, it is possible to measure the focus of the arbitrary circuit pattern area of the chip without a test pattern. We believe the method can contribute to control the scanner and to detect hot spots which appear by focus error. This new method and the evaluation results will be presented in detail in this paper.

Consideration of correlativity between litho and etching shape

We developed an effective method for evaluating the correlation of shape of Litho and Etching pattern. The purpose of this method, makes the relations of the shape after that is the etching pattern an index in wafer same as a pattern shape on wafer made by a lithography process. Therefore, this method measures the characteristic of the shape of the wafer pattern by the lithography process and can predict the hotspot pattern shape by the etching process. The method adopts a metrology management system based on DBM (Design Based Metrology). This is the high accurate contouring created by an edge detection algorithm used wafer CD-SEM. Currently, as semiconductor manufacture moves towards even smaller feature size, this necessitates more aggressive optical proximity correction (OPC) to drive the super-resolution technology (RET). In other words, there is a trade-off between highly precise RET and lithography management, and this has a big impact on the semiconductor market that centers on the semiconductor business. 2-dimensional shape of wafer quantification is important as optimal solution over these problems. Although 1-dimensional shape measurement has been performed by the conventional technique, 2-dimensional shape management is needed in the mass production line under the influence of RET. We developed the technique of analyzing distribution of shape edge performance as the shape management technique. In this study, we conducted experiments for correlation method of the pattern (Measurement Based Contouring) as two-dimensional litho and etch evaluation technique. That is, observation of the identical position of a litho and etch was considered. It is possible to analyze variability of the edge of the same position with high precision.

Study of shape evaluation for mask and silicon using large field of view

We have developed a highly integrated method of mask and silicon metrology. The aim of this integration is evaluating the performance of the silicon corresponding to Hotspot on a mask. It can use the mask shape of a large field, besides. The method adopts a metrology management system based on DBM (Design Based Metrology). This is the high accurate contouring created by an edge detection algorithm used in mask CD-SEM and silicon CD-SEM. Currently, as semiconductor manufacture moves towards even smaller feature size, this necessitates more aggressive optical proximity correction (OPC) to drive the super-resolution technology (RET). In other words, there is a trade-off between highly precise RET and mask manufacture, and this has a big impact on the semiconductor market that centers on the mask business. As an optimal solution to these issues, we provide a DFM solution that extracts 2-dimensional data for a more realistic and error-free simulation by reproducing accurately the contour of the actual mask, in addition to the simulation results from the mask data. On the other hand, there is roughness in the silicon form made from a mass-production line. Moreover, there is variation in the silicon form. For this reason, quantification of silicon form is important, in order to estimate the performance of a pattern. In order to quantify, the same form is equalized in two dimensions. And the method of evaluating based on the form is popular. In this study, we conducted experiments for averaging method of the pattern (Measurement Based Contouring) as two-dimensional mask and silicon evaluation technique. That is, observation of the identical position of a mask and a silicon was considered. The result proved its detection accuracy and reliability of variability on two-dimensional pattern (mask and silicon) and is adaptable to following fields of mask quality management. •Discrimination of nuisance defects for fine pattern. •Determination of two-dimensional variability of pattern. •Verification of the performance of the pattern of various kinds of Hotspots. In this report, we introduce the experimental results and the application. We expect that the mask measurement and the shape control on mask production will make a huge contribution to mask yield-enhancement and that the DFM solution for mask quality control process will become much more important technology than ever. It is very important to observe the form of the same location of Design, Mask, and Silicon in such a viewpoint. And we report it about algorithm of the image composition in Large Field.