Photoetching machine exposure method

Abstract

The invention provides a photoetching machine exposure method which is used for scanning a stepping photoetching machine. The photoetching machine exposure method comprises the following steps of: 1, inclining a slit-shaped lens for a certain angle along a scanning direction of a photoetching mask objective table and a wafer objective table so that the focal length of light projected to a wafer from the slit-shaped lens is gradually changed; and 2, scanning the photoetching mask objective table and the wafer objective table to perform exposure. Compared with the prior art, the photoetching machine exposure method has the beneficial effects that one-time exposure is equivalent to the conventional multi-focal-length repeated exposure, so the method is convenient and quick; furthermore, the focal length range is changed continuously and linearly; and in a focal depth range, an exposed picture has more uniform contrast and a larger technical window can be obtained.

Description

technical field [0001] The invention relates to an exposure method for a photolithography machine, in particular to an exposure method for a scanning and stepping photolithography machine. Background technique [0002] In the modern semiconductor lithography process, in order to improve the lithography process window, multi-focal length repeated exposure is a commonly used technology. With the reduction of the line width of the semiconductor process, Resolution Enhancement Technology (RET, Resolution Enhancement Technology) is also widely used in the advanced process. One of the techniques is to take multiple exposures at different focal length planes to increase the focal depth range (DOF, depth of focus) of the exposure, and at the same time improve the entire lithography process window (DOF-EL, Depth of Focus and Exposure Latitude ). In the multiple focal length exposure method, the final image contrast pair is homogenized in the entire focal length range, and the image...

AI Technical Summary

Problems solved by technology

[0005] When the stepper lithography machine is imaging, the pattern of the lithography plate is imaged through the entire lens area at one time. Therefore, repeated exposure with multiple focal lengths can only be done by changing the focal length multiple times and repeating exposure multiple times. The sacrifice of production capacity is inevitable. of

[0006] In addition, under normal circumstances, the lens plane of the scanning stepper is parallel to the plane of the wafer or the plane of the photolithography plate, and the same method as the stepper can be used to move the upper and lower distances of the wafer stage Changing the focal length to complete multi-focal length repeated exposure, but this is also at the expense of productivity

[0007] The above-mentioned existing multi-focal length repeated exposure method increases the original conventional exposure method from one time to multiple times. Although the process window of lithography is increased, the production capacity of the equipment is reduced, which is not suitable for mass production.

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