CN-122015659-A - In-situ detection method for cosine installation errors between self-tracing grating interference type workpieces

CN122015659ACN 122015659 ACN122015659 ACN 122015659ACN-122015659-A

Abstract

The invention discloses an in-situ detection method for cosine installation errors between self-tracing grating interference type workpieces, which belongs to the technical field of precise measurement and comprises the steps of respectively depositing self-tracing gratings on two workpieces to be measured, simultaneously measuring grating interference signals through two self-tracing grating interferometers which move cooperatively, adjusting the periodic direction of one self-tracing grating to be consistent with the motion measuring axis direction of a high-precision displacement table, enabling two reading heads of the self-tracing grating interferometers to be ideally installed relative to the respective gratings through debugging interference optical signals, respectively acquiring displacement signals of the two self-tracing gratings through the two reading heads of the self-tracing interferometers along with the displacement of the self-tracing gratings, and calculating to obtain the cosine installation errors between the workpieces through comparing the ratio of the period numbers of original signals acquired by the two reading heads. The method solves the problem of in-situ detection of the cosine installation error of the workpiece, and has the advantages of self-calibration of the magnitude, high measurement accuracy and environmental interference resistance.

Inventors

CHENG XINBIN
LI TONGBAO
Xue Dongbai
HE CHUNLING
DENG XIAO
LI YAO
LIN ZICHAO
WANG JUN
XIE YUYING
WEI ZHENBO

Assignees

同济大学

Dates

Publication Date: 20260512
Application Date: 20260212

Claims (10)

1. The in-situ detection method for cosine installation errors between self-tracing grating interference type workpieces is characterized by comprising the following steps of: S1, respectively depositing self-tracing gratings on two workpieces to be detected, and respectively performing coarse alignment on the two workpieces to be detected in a parallel state of the two self-tracing gratings along the grating period direction, so as to simultaneously measure grating interference signals through two self-tracing grating interferometers which move cooperatively; s2, adjusting the periodic direction of the first grating to be consistent with the direction of a motion measuring axis of the high-precision displacement table, and enabling two reading heads of the self-tracing grating interferometer to be ideally installed relative to the respective grating by debugging interference optical signals; S3, along with the displacement of the self-tracing gratings, two reading heads of the self-tracing interferometer respectively and simultaneously collect displacement signals of the two self-tracing gratings; s4, calculating to obtain the cosine installation error between the workpieces by taking the displacement measurement signal of one reading head as a reference and utilizing the theoretical distance of the self-tracing grating and comparing the ratio of the cycle numbers of the original signals acquired by the two reading heads.
2. The method for in-situ detection of cosine installation errors between self-tracing grating interference type workpieces according to claim 1 is characterized in that two workpieces to be detected are roughly aligned in a parallel state of two self-tracing gratings along a grating period direction, wherein a first grating period direction is strictly parallel to a first workpiece reference direction and fixed, and a second grating period direction is strictly parallel to a second workpiece reference direction and fixed.
3. The in-situ detection method for cosine installation errors between interference type workpieces of a self-tracing grating according to claim 1, wherein the self-tracing grating is deposited through a precisely machined ultra-high perpendicularity orthogonal reflecting mirror and a clamp, and the deposition direction of a grating line of the self-tracing grating is guaranteed to be strictly parallel to the reference direction of the workpieces.
4. The method for in-situ detection of cosine installation errors between self-tracing grating interference type workpieces according to claim 1, wherein the laser wavelength of a self-tracing grating interferometer reading head light source module is smaller than twice the theoretical distance between self-tracing gratings.
5. The method for in-situ detection of cosine installation errors between self-tracing grating interference type workpieces according to claim 1, wherein the method for achieving ideal installation of the self-tracing grating and the reading head is that laser is incident to the self-tracing grating at a littrow angle and returns in a primary way, so that interference signals are strongest.
6. The method for in-situ detection of cosine installation errors between self-tracing grating interference type workpieces according to claim 1 is characterized in that a reading head module of the self-tracing grating interferometer at least comprises two reading heads, and the reading head module of the self-tracing grating interferometer adopts any displacement measurement mode of homodyne interference, heterodyne interference and self-mixing interference.
7. The method for in-situ detection of cosine installation errors between workpieces by self-tracing grating interference according to claim 1, wherein the readhead modules of the self-tracing grating interferometer are respectively in the same motion direction with the corresponding self-tracing gratings.
8. The method for in-situ detection of cosine installation errors between self-tracing grating interference type workpieces according to claim 1, wherein in step S2, the periodic direction of the first grating is adjusted to be consistent with the direction of the motion measuring axis of the high-precision displacement table, no interference signal is generated when displacement perpendicular to the motion measuring axis is given at this time, the ideal installation of the first readhead and the first grating is ensured, and the signals collected by the first readhead at this time are: ; Wherein, the Representing the period of the first grating and, Is the distance of the displacement platform movement.
9. The method for in-situ detection of cosine installation errors between interference type workpieces of self-tracing grating as set forth in claim 8, wherein step S3 comprises the steps of simultaneously moving the first grating and the second grating, wherein the first reader and the second reader respectively collect interference original signals of the first grating and the second grating, and the installation angle errors are rotation angles due to the grating period of the second grating and the installation angle errors of the first grating Pitch angle of Angle of deflection Then the second readhead acquires the signal: ; Wherein, the Representing the period of the second grating.
10. The method for in-situ detection of cosine installation errors between workpieces by self-tracing grating interference type according to claim 9, wherein step S4 comprises the following steps of based on theoretical spacing of self-tracing grating by taking displacement measurement signals of a first reading head as a reference And by comparing two phase signals And And obtaining the comparison result of displacement measurement signals of the two self-tracing grating interferometers: ; Wherein, the And Representing displacement measurement results of the second reading head and the first reading head respectively; obtaining two workpiece installation cosine errors through comparison The following are provided: 。

Description

In-situ detection method for cosine installation errors between self-tracing grating interference type workpieces Technical Field The invention relates to the technical field of precision measurement, in particular to an in-situ detection method for cosine installation errors between self-tracing grating interference type workpieces. Background Precision manufacturing and measurement are key technologies to support strategic and pilot industry development. The high-end equipment is used as a core support for industrial development, and the performance index of the high-end equipment is directly influenced by the assembly precision of each component. Taking a core equipment-double workpiece stage photoetching machine for integrated circuit manufacture as an example, the pose precision between two workpiece stages and between each workpiece stage and a main reference of a system is a basic stone for determining the photoetching machine alignment precision and yield. Six degrees of freedom errors in assembly and operation of the workpiece table, particularly pitch, roll, etc., in the vertical direction must be tightly controlled at the micro-arc measurement level. These angle errors can directly introduce abbe errors and cosine errors, resulting in deviations of the actual exposure pattern position from the ideal position. Therefore, high-precision measurement and control of assembly angle errors between the double workpiece stages becomes a key for realizing high-end lithography manufacturing. In industrial practice, the assembly error is generally measured with high precision by means of a laser interferometer, optical microscopic imaging and other technologies. The principle of the laser interferometer for calibrating the workpiece installation error is to utilize the laser wavelength as a scale and calculate displacement or angle deviation by measuring the optical path difference. Because the laser wavelength is easily disturbed by the environment, the robustness is poor, and the high-precision measurement requirement of the industrial field is difficult to adapt. The optical microscopy and imaging technology captures alignment marks on the workpieces through microscopic imaging or diffraction optical technology, calculates the relative positions of the two workpieces through optical signal processing, is generally difficult to trace, and meanwhile, has limited measurement range, and cannot meet the requirement of large-scale measurement. Therefore, there is a need for an in-situ detection method for cosine installation errors between workpieces, which is environmentally robust, traceable and highly accurate. Disclosure of Invention The invention aims to provide an in-situ detection method for cosine installation errors between self-tracing grating interference type workpieces, which aims to solve the problems in the background technology. In order to achieve the above purpose, the invention provides an in-situ detection method for cosine installation errors between self-tracing grating interference type workpieces, which comprises the following steps: S1, respectively depositing self-tracing gratings on two workpieces to be detected, and respectively performing coarse alignment on the two workpieces to be detected in a parallel state of the two self-tracing gratings along the grating period direction, so as to simultaneously measure grating interference signals through two self-tracing grating interferometers which move cooperatively; s2, adjusting the periodic direction of the first grating to be consistent with the direction of a motion measuring axis of the high-precision displacement table, and enabling two reading heads of the self-tracing grating interferometer to be ideally installed relative to the respective grating by debugging interference optical signals; S3, along with the displacement of the self-tracing gratings, two reading heads of the self-tracing interferometer respectively and simultaneously collect displacement signals of the two self-tracing gratings; s4, calculating to obtain the cosine installation error between the workpieces by taking the displacement measurement signal of one reading head as a reference and utilizing the theoretical distance of the self-tracing grating and comparing the ratio of the cycle numbers of the original signals acquired by the two reading heads. Preferably, the two workpieces to be detected are roughly aligned in parallel along the grating period direction by the two self-tracing gratings respectively, wherein the first grating period direction is strictly parallel and fixed with the first workpiece reference direction, and the second grating period direction is strictly parallel and fixed with the second workpiece reference direction. Preferably, the self-tracing grating realizes deposition through a precisely processed ultra-high perpendicularity orthogonal reflecting mirror and a clamp, and ensures that the deposition direction of a grating line of t