High-accuracy alignment mark structure based on machine vision alignment

Abstract

The invention discloses a high-accuracy alignment mark structure based on machine vision alignment. The shape structure of the high-accuracy alignment mark structure based on the machine vision alignment is in an asymmetric shape, wherein the asymmetric shape comprises non-axial symmetry and non-central symmetry; the high-accuracy alignment mark structure based on the machine vision alignment at least comprises a line array, and the lines of the line array are ranked in parallel; the width of the lines in the line array is different from the width of the line seam among the lines; and the lines in the line array are ranked in a staggered mode. The high-accuracy alignment mark structure disclosed by the invention reduces the influence on the imaging quality of alignment mark figures because of process factors such as optical proximity effect, corrosion accuracy control and the like, thereby enhancing alignment accuracy and alignment efficiency.

Description

technical field [0001] The invention relates to a high-precision alignment mark structure, in particular to a high-precision alignment mark structure based on machine vision alignment. Background technique [0002] In the field of semiconductor processing, especially in the manufacturing process of integrated circuits (IC) or micro devices, lithography and detection technology are undoubtedly the core parts. In a semiconductor chip, the various physical components of transistors, capacitors, resistors, and metal wiring layers are arranged on or within the surface of the wafer. Different devices and their interconnections can be ionized into many layers during IC design (currently mainly EDA design, that is, electronic design automation), and each layer is composed of many planar feature patterns. The photolithography process is to realize the graphic design conversion of the design on the substrate surface, convert the designed and processed planar feature graphics to the c...

AI Technical Summary

Problems solved by technology

In the actual lithography and etching process, due to the influence of the optical proximity effect and the control of etching precision, the slope of the edge of the final alignment mark line is nonlinear and has a large curvature. In the process of image acquisition, The gray level change at the edge of the line is small, the sharpness is not enough, and because the entire alignment mark is axisymmetric or centrosymmetric grating distribution, the optical environment of each grating line is similar, therefore, the edge of each line in the alignment mark The gray scale of the image is similarly affected, resulting in the poor accuracy of pattern matching. It is prone to shift the center position of the alignment mark for image recognition relative to the actual position, and it is random, so the alignment accuracy is also reduced. bit efficiency drop

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