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Phase modulation method, phase modulator, mark alignment system, and readable storage medium

A phase modulator and phase modulation technology, applied in the field of mark alignment system and readable storage medium, phase modulator, and phase modulation method, can solve the problems of not meeting application requirements, limited range of optical path difference, poor versatility, etc. Achieve the effects of stray light, improve precision, and reduce contrast

Active Publication Date: 2021-10-19
SHANGHAI MICRO ELECTRONICS EQUIP (GRP) CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, the current phase modulation technology has poor versatility and can only eliminate the influence of parasitic interference (ie stray light) in a certain range of optical path difference. The range of optical path difference is limited and cannot meet the application requirements of other ranges of optical path difference.

Method used

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  • Phase modulation method, phase modulator, mark alignment system, and readable storage medium
  • Phase modulation method, phase modulator, mark alignment system, and readable storage medium
  • Phase modulation method, phase modulator, mark alignment system, and readable storage medium

Examples

Experimental program
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Embodiment 1

[0059] This embodiment provides a phase modulation method for optical alignment, including:

[0060] Step 1. Take the same modulation frequency and perform multiple measurements. The number of modulation amplitudes and / or the maximum modulation amplitude are different for each measurement, and the modulation amplitude is periodically switched between the corresponding multiple modulation amplitudes during each measurement;

[0061] Step 2. Compare the results of the multiple measurements, and obtain the number of modulation amplitudes and the maximum modulation amplitude corresponding to the optimal measurement result at the modulation frequency.

[0062] Based on the introduction in the above basic principles, in step 1, when the modulation frequency is constant, the number of modulation amplitudes set in a measurement is n, and the maximum modulation amplitude is Then during the time period of this measurement, the maximum modulation amplitude will be included The n modul...

Embodiment 2

[0080] The focal lengths of different lens groups in different optical alignment systems are different, resulting in different positions and ranges of the optical path difference generated by stray light, and the modulation frequency f can determine the range and position of the optical path difference of the stray light fringe contrast. In order to meet the different requirements of different optical alignment systems, this embodiment provides a phase modulation method. Compared with Embodiment 1, after performing steps 1 and 2, step 3 is also performed: changing the modulation frequency, and analyzing the maximum When the modulation amplitude is the same and the number of modulation amplitudes is the same, the measurement results corresponding to different modulation frequencies are used to determine the modulation frequency, the number of modulation amplitudes and the maximum modulation amplitude corresponding to the optimal measurement result among all the measurement result...

Embodiment 3

[0087] In order to meet the requirements of different optical alignment systems, this embodiment provides a phase modulation method, which is different from Embodiment 2 in that it is implemented in the order of step 3, step 1, and step 2, that is, the method of this embodiment Phase modulation methods specifically include:

[0088] First, perform step 3: determine the initial modulation frequency and maximum modulation amplitude according to the requirements of the optical alignment system, and then change the modulation frequency when the maximum modulation amplitude and the number of modulation amplitudes are the same to obtain measurement results corresponding to different modulation frequencies, Determine the optimal measurement result from the measurement results corresponding to these modulation frequencies, and obtain the modulation frequency corresponding to the optimal measurement result as the optimal modulation frequency;

[0089] Then, perform step 1: take the opt...

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Abstract

The invention provides a phase modulation method, a phase modulator, a mark alignment system, and a readable storage medium. Under the condition of a certain modulation frequency, by changing the maximum modulation amplitude and / or the number of modulation amplitudes, the optical The aligned laser is phase-modulated to suppress parasitic interference, so that the contrast of stray light fringes within the range of optical path difference where the stray light corresponding to the modulation frequency disappears is closer to 0, thereby eliminating the influence of stray light and improving optical sensitivity. Accuracy of quasi-signal. Furthermore, the technical solution of the present invention can also effectively increase the range of optical path difference where stray light disappears by changing the modulation frequency, so as to meet the requirements of different optical alignment systems with different focal lengths, and has high versatility.

Description

technical field [0001] The invention relates to the technical field of optical alignment and precision measurement, in particular to a phase modulation method, a phase modulator, a mark alignment system and a readable storage medium. Background technique [0002] In the field of precision alignment and measurement, the degree of optical alignment has a great influence on the precision and accuracy of measurement. Optical alignment technology is a hot spot that researchers care about and study. For example, when using non-diffraction spot for straightness measurement in precision manufacturing engineering, the alignment accuracy of the center of the non-diffraction light ring-shaped spot has a decisive impact on the accuracy of straightness error measurement; another example is in scanning interference field exposure technology , the degree of beam coincidence directly affects the contrast of the interference fringes in the interference field, thereby affecting the quality of...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G03F9/00G02F1/03
CPCG02F1/0327G03F9/7088G03F9/7092
Inventor 胥欣孙建超
Owner SHANGHAI MICRO ELECTRONICS EQUIP (GRP) CO LTD