Overlay mark, and overlay measurement method and semiconductor device manufacturing method using same

Abstract

The present invention relates to an overlay mark, and an overlay measurement method and a semiconductor device manufacturing method using the same. The present invention provides an overlay mark for determining the relative shift between two successive pattern layers or between two or more patterns separately formed on a single layer, the overlay mark comprising: a first overlay structure that includes a pair of first bars facing one another and extending in a first direction, and a pair of second bars facing one another and extending in a second direction that is orthogonal to the first direction; and a second overlay structure that includes a plurality of pairs of third bars parallel to the first bars, and a plurality of pairs of fourth bars parallel to the second bars, wherein the gapsbetween neighbouring third bars are different from one another, and the gaps between neighbouring fourth bars are different from one another. The overlay mark according to the present invention has different gaps between bars, thereby being capable of minimising the occurrence of errors during image analysis.

Description

technical field [0001] The present invention relates to an alignment mark, an alignment measurement method using it, and a semiconductor device manufacturing method. Background technique [0002] On the semiconductor substrate, a plurality of pattern layers are sequentially formed. And, a circuit of one layer is formed by dividing into two patterns by double patterning or the like. Only when such a patterned layer or multiple patterns of one layer are accurately formed to a predetermined position can a desired semiconductor element be manufactured. [0003] Therefore, in order to confirm whether the pattern layer is accurately aligned, an alignment mark formed simultaneously with the pattern layer is used. [0004] The method of determining alignment using the alignment marks is as follows. First, the pattern layer formed in the previous process (eg, etching process) is used as the pattern layer, and at the same time, one structure that is a part of the alignment mark is ...

AI Technical Summary

Problems solved by technology

like figure 1 The mark shown has the following problem: Since a plurality of rods 2 are arranged at equal intervals, when the intensity of the signal is weak, it will be as follows: figure 2 The error shown is read when the image is analyzed shifted one cycle to the left

In this case, there is also a problem that the alignment mark image obtained by the chromatic aberration due to the difference in the refractive index of each wavelength of the light source;

The strain of such an image becomes the reason for reducing the accuracy of the alignment determination

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