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Displacement measurement system and method based on diffraction grating

A diffraction grating and displacement measurement technology, applied in measurement devices, optical devices, instruments, etc., can solve the problems of large occupied space, complex structure, time-consuming and laborious installation, etc., and achieve the effect of convenient installation, simple structure and high measurement accuracy.

Inactive Publication Date: 2017-08-08
SHANGHAI MICRO ELECTRONICS EQUIP (GRP) CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the measurement light and reference light of the traditional interferometer displacement measurement system are exposed to the air and are greatly affected by air disturbance, which gradually cannot meet the increasing accuracy requirements.
[0005] A displacement measurement system is described in the prior art, which includes the relative displacement measurement function of two components in six degrees of freedom, and its structure includes at least two diffraction gratings, sensors, linear polarizers, at least two intensity radiation detection device, etc., but due to its complex structure and large space occupation, installation is time-consuming and laborious

Method used

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  • Displacement measurement system and method based on diffraction grating
  • Displacement measurement system and method based on diffraction grating
  • Displacement measurement system and method based on diffraction grating

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Effect test

Embodiment 1

[0058] Please refer to figure 1 The present invention provides a displacement measurement system based on a diffraction grating, which is placed on the side of a movable worktable. The movable worktable is a mask stage for carrying a mask or a workpiece stage for carrying a silicon wafer 7. 6. In this embodiment, the movable worktable is the workpiece table 6. The lowest end of the displacement measurement system and the bottom surface of the workpiece table 6 are located on the same horizontal plane, and the displacement measurement system sequentially includes:

[0059] A light source 1 for providing measurement light;

[0060] A prism is fixed on one side of the work table 6 to reflect the measuring light. In this embodiment, the prism is a reflecting prism 21, please refer to Figure 4 , The length of the reflecting prism 21 is equal to the length of the side of the workpiece table 6 corresponding to the reflecting prism 21;

[0061] A diffraction grating 3, fixed on the frame 9 ...

Embodiment 2

[0076] Please refer to Figure 5 The difference between this embodiment and the first embodiment is that the light formed after the measuring light is reflected by the reflecting prism 21 intersects the surface of the diffraction grating 3, and the incident surface of the photodetector 4 and the surface of the diffraction grating 3 also intersect.

[0077] Please refer to Image 6 , After the measurement light emitted by the light source 1 is reflected by the reflecting prism 21, the incident angle of the formed reflected light when it enters the diffraction grating 3 is C, and it is diffracted after entering the diffraction grating 3, so the exit angle of the resulting diffracted beam is also The exit angle of the +1-order diffracted light is D, and the exit angle of the -1st-order diffracted light is D'. For the +1-order diffracted light, the grating equation is d(sin C+sin D)=mλ, for For -1 order diffracted light, the grating equation is d(sin C+sin D')=mλ, d is the period of t...

Embodiment 3

[0085] Please refer to Figure 7 The difference between this embodiment and the first embodiment is that the prism is a dichroic prism 22, and the entire displacement measurement system also includes a coupler system.

[0086] The dichroic prism 22 divides the light emitted from the light source 1 into the measurement light incident on the diffraction grating 3 and the reference light transmitted to the coupler system.

[0087] Please refer to Picture 8 The coupler system respectively includes a first coupler 51 that receives the diffracted light diffracted from the diffraction grating 3 by the measurement light, a second coupler 52 that receives the reference light formed by the refraction of the measurement light by the dichroic prism 22, the first coupler 51 and The second coupler 52 is the third coupler 53 of the optical signal transmitted through the optical fiber 41, and the entire coupler system, the beam splitter 22 and the photodetector 4 are also connected through the opt...

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Abstract

The invention provides a displacement measurement system and a method based on a diffraction grating. A light source, a prism, a diffraction grating and a photoelectric detector are arranged, and a corresponding control system is configured. The prism is fixed on a movable worktable, and the diffraction grating is fixed on a machine frame. When the movable worktable moves relative to the machine frame of a lithography machine, the interference fringes produced after the light emitted by the light source is diffracted by the diffraction grating will change. Thus, the control system can obtain the displacement of the movable worktable relative to the machine frame of the lithography machine by calculating the change of the interference fringes. The measurement system is simple in structure and easy to install. Because the system carries out measurement in an airtight package box, the system is less disturbed by the outside environment during measurement, and thus, has higher precision of measurement than the traditional interferometer.

Description

Technical field [0001] The invention relates to the field of semiconductor photoetching machines, in particular to a displacement measurement system and method based on a diffraction grating. Background technique [0002] With the continuous reduction of the device size required by integrated circuits, the lithography machine, as an integrated circuit, transfers the feature pattern on the mask to the substrate, and its accuracy requirements are also increasing, especially the need to continuously improve the light The measurement accuracy of the position of the movable element in the engraving machine. [0003] The movable components in the lithography machine mainly refer to the mask table that carries the mask and the workpiece table that carries the silicon wafer. During the lithography process, the mask table or the workpiece table is displaced relative to the overall frame of the lithography machine , Measuring the displacement of the mask table or the workpiece table relativ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01B11/02
Inventor 陈南曙
Owner SHANGHAI MICRO ELECTRONICS EQUIP (GRP) CO LTD