Abstract
For inspecting LSI reticle patterns automatically with high accuracy, pattern inspection method by comparing reticle patterns with its design data is described.
This method utilizes the data, which controlls a pattern generator for drawing reticle patterns, as a design data, The data consist of an aggregate of rectangles which form the reticle patterns. The data are stored in a magnetic tape in the form of rectangle parameters (center position, width, height, slant angle).
In order to compare the optically detected reticle patterns with the design data, the data are converted to a video signal along the detector's raster scanning line of the patterns. The method for the conversion and block diagrams of the conversion circuits are presented. The circuits generate a video signal from the design data, at high speed. Inspection is then performed by comparing the generated signal with the detected reticle pattern signal.
The structure of the reticle inspection system utilized the developed method is briefly described. The system detect defects as small as 4μm. The time of inspection is 45 minutes for 90×90mm reticle.
