Method for optimizing photoetching process window

Abstract

The invention provides a method for measuring the surface position of a semiconductor structure and a method for optimizing a photoetching process window, and is applied to the technical field of semiconductors. Specifically, in the method for measuring the surface position of the semiconductor structure provided by the invention, the measurement precision of the horizontal surface position of the semiconductor structure (wafer) is improved by changing the wavelength of a detection laser beam of a surface horizontal sensing system, so that based on the process in the prior art, the problem of low wafer surface measurement precision caused by the light transmission of the photoresist is solved. Moreover, in the method for optimizing the photoetching process window provided by the invention, the heights of different areas on the surface of the wafer are accurately measured by using the surface horizontal sensing system for detecting the wavelength reduction of the laser beam, the height is adjusted based on the height, and then the exposure process is carried out on the wafer after the horizontal plane is adjusted, so that better focusing is achieved during exposure, and a photoetching process window is further improved.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a method for measuring the surface position of a semiconductor structure and a method for optimizing a photolithography process window. Background technique [0002] With the research and development of high-integration, ultra-high-speed, and ultra-high-frequency integrated circuits and devices, the feature size of large-scale integrated circuits and ultra-large-scale integrated circuits is becoming smaller and smaller, and the processing size enters deep submicron, hundreds of nanometers or even nanometers. In the field of microelectronics technology, micro-lithography technology is the highest precision processing technology that humans can achieve so far. However, the further development of integrated circuits requires the support of corresponding exposure technology. Photoresist technology is an important part of exposure technology. [0003] Usually, there are various...

AI Technical Summary

Problems solved by technology

[0004] However, due to the light transmittance of the photoresist used as the exposure surface, only 5% (transverse magnetic wave) to 35% (transverse electric wave) of the laser light irradiated on the wafer surface is used as reflected light by the sensor of the surface level sensing system Receive, even if the incident angle is adjusted, there will still be a lot of light penetrating below the exposure surface, which will affect the measurement accuracy of the wafer surface

For semiconductor structures with variable wire distribution and film layers in the back-end wiring layer, the surface detection error can be as high as ±0.05~0.15um, which obviously cannot meet the design requirements.

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