Designing method for multi-partition optical phase plate in photo-etching illumination

Abstract

The invention relates to a designing method for a multi-partition optical phase plate in photo-etching illumination, which is characterized by comprising the following steps of: (1) calculating the size l of a phase unit; (2) selecting the partition size d of the optical phase plate; (3) emitting a light beam and determining the light distribution of required light beam, and carrying out matrix process; (4) assigning the initial phase in one partition in the phase plate; (5) processing discretization process with iterative algorithm to obtain the phase distribution of the partition; (6) repeating the step (4) and the step (5) in each partition one by one to obtain the phase distribution of each partition and combine the phase distribution so as to obtain the integral phase distribution; and (7) estimating the designing result. The optical phase plate designed by the invention has the characteristic of insensitivity property for position, size, shape and light distribution of the emitted light beam so that the required output light distribution can be obtained.

Description

technical field [0001] The invention belongs to the field of microlithography, and relates to very large-scale integrated circuit manufacturing equipment, in particular to a design method of a multi-section optical phase plate used for lithography illumination. Background technique [0002] In the illumination system of a lithography machine, in order to improve the quality of lithography, various resolution enhancement technologies are usually used, and off-axis illumination is one of the important technologies. Off-axis illumination technology converts the light intensity distribution in the cross-section of the laser output beam into a specific light intensity distribution that can improve imaging resolution. This specific light intensity distribution can be used for different mask patterns. The distribution can also be a uniform circular distribution. Generally, the light source of the lighting system is usually an excimer laser operating in the form of a pulse. The las...

AI Technical Summary

Problems solved by technology

For excimer lasers used in lithography machines, the position, size and light intensity distribution of the beam have obvious jitter and instability; and because there is usually a transmission distance of 5 to 20 meters between the laser and the lighting system of the lithography machine, The relative change between the laser and the lithography machine installation foundation is inevitable. Although technical measures have been taken to stabilize the position and light intensity of the laser beam in the lighting system, this effect has not been completely eliminated.

The current design method can no longer meet the needs of actual use

[0006] 2. The design requires a large amount of computation, takes a long time, and requires high computing equipment

Since the laser wavelengths used in mainstream lithography machines are in the ultraviolet band, such as 193nm and 248nm, etc., the size of the phase unit of the optical phase plate is limited, so when the overall size is determined, the number of units is very large, so the calculation is very large , and need to store a large amount of data

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