Semiconductor process method

Abstract

The invention provides a semiconductor process method, which comprises the following steps of 1) providing a background plate, and forming a rectangle on the background plate by using a positioning mark point, 2) placing the wafer in the rectangle of the positioning mark point with the back face upward, and photographing to obtain an ellipse-like wafer picture and the positioning mark point, 3) editing the picture, and marking the positions corresponding to the edge gaps and the defects of the wafer, 4) finding out wafer edges, defects, edge gaps and positioning mark points on the picture, (5) transforming the positioning mark points into rectangles with the same size as the rectangles in the step 1), 6) transforming the defect and the edge gap back to the position of the back of the original wafer, and reconstructing the depth distortion of the picture, 7) performing mirror surface overturning on the wafer, and 8) superposing the front defect position and the back defect position of the wafer to identify the chip with at least one of the front defect and the back defect. The defect of the back surface of the wafer can be accurately reflected to the front surface of the wafer, so that all defective chips can be accurately detected.

Description

technical field [0001] The invention relates to the field of semiconductor chip manufacturing, in particular to a semiconductor process method. Background technique [0002] Before the wafer is diced to separate the wafer into individual chips, there is usually a final inspection of the wafer. In this inspection, the chip has poor reliability or For other defects, it is necessary to mark the chip with defects, which is usually called "ink pass die" process. Any defect on the front and back of the wafer corresponding to the same chip needs to be marked, so the back defect of the wafer is reflected to the front of the wafer to finally determine all defects based on the front and back defects of the wafer. The location of the defective chip is very important. In the prior art, the backside of the wafer is usually photographed after the ink pass die is completed, and the positions of the defective chips on the picture are fitted to the front side of the wafer, and then cut acc...

AI Technical Summary

Problems solved by technology

In the prior art, the backside of the wafer is usually photographed after the ink pass die is completed, and the positions of the defective chips on the picture are fitted to the front side of the wafer, and then cut according to the fitting result. However, due to the optical and image Due to various reasons such as depth scaling, errors are prone to occur in this process, and all defective chips cannot be correctly identified.

Specifically, optical reasons include unexpected offset during the photographing process, shadows caused by foreign objects, optical reflections, etc., or the color of the wafer is similar to the background and it is difficult to identify the wafer from the background, or it is difficult to identify the wafer The direction of the kerf, etc.; and the problem in the process of image depth scaling is usually due to the problem of the shooting angle that the captured wafer image is usually ellipsoidal, and it is difficult to reconstruct the defects on the wafer based on the ellipsoidal wafer image.

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