Alignment method of wafer and mask plate and overlay method of nano structure

Abstract

The invention relates to a wafer and mask alignment method and a nanostructure overlay method, and the alignment method comprises the steps: S1, moving a mask to a wafer, and enabling the mask and the wafer to be located in a scanning region of an imaging device based on a near-field scanning optical microscope principle, the reference benchmark used for being aligned with the mask plate moved to the wafer in the step is exposed; s2, scanning the scanning area by using a scanning device to obtain first position data of the reference mark and second position data of the alignment mark; s3, for each piece of first position data, determining a minimum relative distance between the first position data and the second position data; and S4, moving the mask plate to enable the minimum relative distance to be within a preset distance range. According to the wafer and mask alignment method and the nanostructure overlay method, optical imaging under the nanoscale can be realized, so that high-precision overlay alignment is realized.

Description

technical field [0001] The invention relates to an alignment method of a wafer and a mask and a nanostructure overlay method, which are applied to overlay technology and belong to the technical field of semiconductors. Background technique [0002] In a manufacturing process of a semiconductor device, when a stacked structure having a circuit pattern of a semiconductor device is formed, a photolithography process is performed on each layer. In the circuit pattern, connections must also be formed between the upper and lower layers. Therefore, the overlay accuracy of the patterns of the respective layers is important. At present, in the field of semiconductors such as microelectronics, the realization of overlay through reticle usually includes three categories: projection method (achieved by projection lithography machine), nanoimprint technology and contact lithography technology (that is, generalized contact lithography technology) The generalized contact lithography tech...

AI Technical Summary

Problems solved by technology

However, it cannot be applied to the overlay process of near-working distance gap imaging lithography. At present, the current near-working distance gap imaging lithography is based on the principle of optical microscopy to achieve overlay. However, for the principle of traditional optical microscopy, its resolution There is a 1 / 4 wavelength linewidth resolution limit

The wavelength of the light source used is narrowed from the ultraviolet band (g-line and i-line of mercury lamp) to the 193nm deep ultraviolet band. If you enter into a shorter wavelength light source, such as extreme ultraviolet (EUV), X-ray, etc., not only is it difficult to obtain a high-power light source, but the cost is high , and the supporting technology has poor compatibility and inheritance

Therefore, affected by the resolution limit of traditional optical microscope technology, it is easy to cause the exposure pattern to deviate from the actual position, which affects the overlay accuracy of the lithography machine, and then affects the performance of the semiconductor device.

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