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Automatic focusing method and device for lithography machine

A technology of automatic focusing and lithography, which is applied in opto-mechanical equipment, optics, instruments, etc., and can solve the problems of small measurement range, low measurement accuracy, and complex structure.

Active Publication Date: 2013-01-02
HUAZHONG UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage of this device is that the structure is too complicated, the measurement range is small, and the measurement accuracy is low, which is difficult to meet the needs of the current technology.

Method used

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  • Automatic focusing method and device for lithography machine
  • Automatic focusing method and device for lithography machine
  • Automatic focusing method and device for lithography machine

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Experimental program
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Effect test

Embodiment Construction

[0035] Such as figure 1 Shown, the inventive method comprises the following steps:

[0036] (1) Convert the light beam from the light source of the lithography machine into a parallel beam, and first project it onto the surface of the silicon wafer through a slit, and the width of the slit is recorded as d;

[0037] (2) Utilize the vibrating mirror to receive the reflected light beam on the surface of the silicon wafer, the amplitude of the vibrating mirror is 0.5d, and the frequency is denoted as f;

[0038] Let the defocus amount of the silicon wafer be z, and the offset of the reflected beam caused by the silicon wafer offset is recorded as k, and the relationship between the two satisfies:

[0039] k=2γ·sinα·z (I)

[0040] In the formula, γ is the magnification of the light path system from the light source to the silicon wafer, and α is the incident angle of the beam projected to the silicon wafer, both of which are constant values ​​in the focusing system.

[0041] (3...

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Abstract

The invention discloses an automatic focusing method and an automatic focusing device for a lithography machine. The method comprises the following steps of: projecting parallel beams onto the surface of a silicon wafer through a first slit; scanning the beams by a vibration reflector and making the beams pass a second slit; receiving a light intensity signal by a photoelectric detector; extracting frequency domain components of which the frequency is 2 times scanning frequency from the light intensity signal to obtain the coarse tuning amount of the silicon wafer; extracting frequency domaincomponents of which the frequency is doubling the scanning frequency from the light intensity signal to obtain the fine tuning amount of the silicon wafer; and adjusting the silicon wafer to a focus position by a driving device. The focusing device mainly comprises the two slits, the vibration reflector, a photoelectric sensor, a drive platform and a plurality of optical lenses; and the signal processing procedure is finished by computer programming. Compared with the conventional focusing method by comparing the intensities of light spots, the method and the device have the characteristics of simple structure, quick response, high precision (higher than 0.1 microns) and strong antijamming capability.

Description

technical field [0001] The invention belongs to the technical field of automatic focusing of photolithography machines and photoelectric detection, and in particular relates to an automatic focusing method and device of photolithography machines. Background technique [0002] With the vigorous development of the electronic industry, the application of integrated circuits has become more and more extensive, and the high precision of its production has also received more attention. Lithography machine is the most critical equipment in all links of integrated circuit production. Lithography technology is the basis of large-scale integrated circuit manufacturing and the core driving force to promote the development of integrated circuits. Graphics are imaged on silicon wafers. Since the surface of the silicon wafer is coated with photosensitive photoresist, when the pattern on the mask plate is imaged on the silicon wafer, the photoresist at the corresponding position will prod...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G03F7/027
Inventor 刘世元张鹏
Owner HUAZHONG UNIV OF SCI & TECH
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