Photoetching machine projection objective lens wave aberration field measurement method

Abstract

The invention discloses a photoetching machine projection objective lens wave aberration field measurement method, which utilizes a measurement system. The system comprises a light source, a lighting system, a mask table, a projection objective lens, a six-dimensional scanning worktable and an image sensor, wherein the light source is used for generating lighting light beams; the lighting system is used for adjusting the lighting light beams; the mask take can carry a test mask and position accurately; the projection objective lens can image a graph on the test mask and has an adjustable numerical aperture; the six-dimensional scanning worktable can position accurately; the image sensor is arranged on the six-dimensional scanning worktable and is used for measuring the image of the graph on the test mask; and the lighting system can adjust a beam waist size, light intensity distribution, a partial coherence factor and a lighting mode. When in measurement, the light intensity distribution of an aerial image is simulated and analyzed and a linear model of a Zernike coefficient is established based on the simulation and analysis first and then the Zernike coefficient is obtained by fitting by utilizing the linear model according to the aerial image measured by the image sensor.

Description

technical field [0001] The invention relates to an on-site measurement method for the wave aberration of a projection objective lens of a lithography machine. Background technique [0002] Step and scan projection lithography machines for photolithographic processes are well known in the field of very large scale integrated circuit fabrication. The projection objective lens system is one of the most important subsystems in a step-and-scan projection lithography machine. The wave aberration of the projection objective lens deteriorates the lithography imaging quality of the lithography machine and reduces the lithography process window. Wave aberration can be divided into odd aberration and idol aberration. Among them, the odd aberration mainly includes coma and triple wave aberration, and the idol aberration mainly includes spherical aberration and astigmatism. The coma aberration of the projection objective lens makes the imaging position shift after the pattern on the m...

AI Technical Summary

Problems solved by technology

[0004] TAMIS technology needs to use more than ten kinds of illumination settings when measuring the wave aberration of the projection objective lens, so the measurement speed is slow

Moreover, the number of Zernike coefficients that can be measured by TAMIS technology is very limited, only limited to Z 5 ,Z 7 ,Z 8 ,Z 9 ,Z 12 ,Z 14 ,Z 15 ,Z 16 ,Z 21 , and with the continuous reduction of lithographic feature size, the measurement accuracy of TAMIS technology is gradually unable to meet the requirements

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