Measuring method for dose uniformity of lithography machine

Abstract

The invention discloses a method for testing the dose uniformity of a photolithography machine. The test method includes: uploading the reticle to be exposed, which includes monitoring marks; using the reticle to be exposed to perform focal plane-dose matrix exposure to obtain the overlay error of the monitoring marks under different focal lengths and exposure doses; determining the focal length, exposure The relationship matrix between dose and overlay error; determine the exposure dose action interval according to the relationship matrix; use any exposure dose within the exposure dose action interval to perform focal length matrix exposure on the mask to be exposed; obtain the actual overlay error of the monitoring mark; according to the relationship The matrix and the actual overlay error determine the actual exposure dose of each point in the exposure field to obtain the dose uniformity of the lithography machine. The technical solution of the invention can adapt to various working conditions, and can also eliminate the interference of the focal plane and aberration, so that the exposure dose and dose uniformity of the photolithography machine can be accurately measured.

Description

technical field [0001] Embodiments of the present invention relate to the technical field of lithography machines, and in particular, to a method for measuring dose uniformity of a lithography machine. Background technique [0002] The exposure dose of the lithography machine refers to: the light energy of a specific wavelength (or wavelength range) accumulated on the unit area of ​​the silicon wafer during the exposure process, that is, the integral of the illumination light intensity on the silicon wafer surface to the exposure time. On this basis, dose uniformity refers to the control accuracy of the exposure dose at different positions of the lithography machine in the exposure field. At present, the dose uniformity test of the lithography machine is mainly realized by the internal sensor of the machine. There are mainly two detectors that can test the dose in the lithography machine, one belongs to the illumination subsystem, located in the illumination light path, and...

AI Technical Summary

Problems solved by technology

Lithography machines often adopt a fixed mode when using sensors to measure. However, the actual working conditions are complex and changeable, and the final exposure results may be different from the sensor measurement results. Therefore, an accurate process test method is needed to characterize the dose uniformity of the lithography machine.

For this, process engineers usually use critical dimension uniformity (Critical Dimension Uniformity, CDU) to monitor the state of the lithography machine, but ordinary patterns are affected by focal planes and aberrations, and it is difficult to characterize the dose uniformity of the lithography machine through critical dimension uniformity

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