CN118089534A - High-precision error calibration device for Fizeau interferometer - Google Patents
High-precision error calibration device for Fizeau interferometer Download PDFInfo
- Publication number
- CN118089534A CN118089534A CN202410076355.2A CN202410076355A CN118089534A CN 118089534 A CN118089534 A CN 118089534A CN 202410076355 A CN202410076355 A CN 202410076355A CN 118089534 A CN118089534 A CN 118089534A
- Authority
- CN
- China
- Prior art keywords
- mirror
- calibrated
- interferometer
- light
- fizeau interferometer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000013307 optical fiber Substances 0.000 claims abstract description 19
- 238000003384 imaging method Methods 0.000 claims abstract description 16
- 238000005259 measurement Methods 0.000 claims abstract description 15
- 230000001427 coherent effect Effects 0.000 claims abstract description 13
- 230000010287 polarization Effects 0.000 claims abstract description 10
- 230000003287 optical effect Effects 0.000 claims description 21
- 230000004075 alteration Effects 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 6
- 230000009897 systematic effect Effects 0.000 claims description 4
- 238000005286 illumination Methods 0.000 claims description 2
- 238000005305 interferometry Methods 0.000 claims description 2
- 238000000034 method Methods 0.000 description 12
- 238000001514 detection method Methods 0.000 description 9
- 238000010586 diagram Methods 0.000 description 4
- 241000282326 Felis catus Species 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000011065 in-situ storage Methods 0.000 description 1
- 238000001259 photo etching Methods 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B9/00—Measuring instruments characterised by the use of optical techniques
- G01B9/02—Interferometers
- G01B9/02055—Reduction or prevention of errors; Testing; Calibration
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Instruments For Measurement Of Length By Optical Means (AREA)
Abstract
The invention discloses a high-precision error calibration device for a Fizeau interferometer, which comprises a light source, a point diffraction interferometer and a Fizeau interferometer to be calibrated, wherein the light source is used for generating short coherent light and heterodyning phase shifting; the point diffraction interferometer is used for measuring the surface shape of a reference surface of the Fizeau interferometer to be calibrated and emitting a point diffraction spherical wave; the point diffraction interferometer comprises an optical fiber coupler, a first converging mirror, a second converging mirror, a point diffraction plate, a first reflecting mirror, a first imaging mirror and a first detector; the to-be-calibrated Fizeau interferometer comprises a standard spherical mirror, a polarization beam splitter prism, a collimating mirror, a second reflecting mirror, a second imaging mirror and a second detector. The device utilizes the point diffraction interferometer to calibrate the surface shape error of the reference surface and the system error of the Fizeau interferometer, and further obtains high-precision absolute surface shape data of the measured element, so as to break the limitation of the standard spherical mirror surface shape processing precision on the system measurement precision.
Description
Technical Field
The invention relates to the technical field of optical measurement, in particular to a high-precision error calibration device for a Fizeau interferometer.
Background
The high-end optical equipment represented by a projection exposure system of a deep ultraviolet photoetching machine provides great challenges for processing optical elements and integrating optical systems, and the interferometer is used as core detection equipment which is indispensable for processing high-precision optical elements and integrating optical systems, so that the detection precision requirements are continuously improved. The high-precision surface shape detection interferometer mainly comprises a Tamangreen interferometer and a Fidelity interferometer, and compared with the Tamangreen interferometer, the Fidelity interferometer has the advantages of simple structure and strong anti-interference capability due to the characteristic of a common optical path of reference light and measuring light of the Fidelity interferometer, and is wider in practical application.
In order to improve the measurement accuracy of the Fizeau interferometer, the existing method mainly uses a spherical absolute detection technology to calibrate the surface shape error of a reference surface or separates absolute surface shape information of a measured surface by processing a plurality of measurement results. The sphere absolute detection technology mainly comprises a double sphere method, a random sphere method, a rotation translation method and the like. The bi-spherical method needs to measure the measured mirror at the cat eye position (the focal position of the standard spherical mirror), the conventional position (the confocal position of the standard spherical mirror and the measured mirror) and the rotating position of 180 degrees for three times, and obtains the absolute surface shape data of the measured mirror through a data processing method, but the method has high requirements on the optical axis alignment precision due to the need of rotating the measured mirror, and is difficult to accurately position the cat eye position, so that the absolute detection precision is influenced; the method has the advantages that the convergent light beam of the standard spherical mirror is incident on the sphere, the sphere rotates randomly around the sphere center after one-time detection is finished, the average result is measured for multiple times, the measurement result can be considered to only comprise the surface shape error of the reference surface, the subsequent measurement result can be deducted, the method has higher requirements on the surface shape precision of the random sphere, more detection times are needed, and certain requirements on environmental stability are provided; the rotation translation method obtains the rotation asymmetric component of the surface shape error by rotating the measured mirror at a plurality of equal angles, and obtains the rotation symmetric component of the surface shape error by translation, so as to obtain the surface shape information of the measured surface.
Disclosure of Invention
The invention aims to provide a high-precision error calibration device for a Fizeau interferometer, which utilizes a point diffraction interferometer to calibrate the surface shape error and the system error of a reference surface of the Fizeau interferometer, so as to obtain high-precision absolute surface shape data of a measured element, and break the limitation of standard spherical mirror surface shape processing precision on the system measurement precision.
The invention aims at realizing the following technical scheme:
a high accuracy error calibration device for a fizeau interferometer, the device comprising a light source, a point diffraction interferometer and a fizeau interferometer to be calibrated, wherein:
The light source is used for generating short coherent light and heterodyning phase shifting;
the point diffraction interferometer is used for measuring the surface shape of the reference surface of the Fizeau interferometer to be calibrated and emitting a point diffraction spherical wave;
The point diffraction interferometer comprises an optical fiber coupler, a first converging mirror, a second converging mirror, a point diffraction plate, a first reflecting mirror, a first imaging mirror and a first detector, wherein:
When the surface shape error of the reference surface of the Fizeau interferometer to be calibrated is calibrated, short coherent light generated by the light source is coupled to an optical fiber coupler in the point diffraction interferometer through an optical fiber, and then laser is respectively incident to a first converging mirror and a second converging mirror;
Then forming convergence points at pinholes of the point diffraction plates, respectively diffracting to generate reference light and measuring light, wherein the measuring light is incident on a reference surface of a standard spherical mirror of the Fizeau interferometer to be calibrated, and the point diffraction plates are positioned at focuses of the standard spherical mirror, so that reflected light of the reference surface of the standard spherical mirror is converged on a metal reflecting film layer near the pinholes of the point diffraction plates, and enters the first imaging mirror together with the reference light through the first reflecting mirror, finally low-frequency heterodyne interference is generated on the first detector, and then the surface shape error of the reference surface of the Fizeau interferometer to be calibrated can be calculated from an interference pattern collected on the first detector;
The to-be-calibrated Fizeau interferometer comprises a standard spherical mirror, a polarization beam splitter prism, a collimating mirror, a second reflecting mirror, a second imaging mirror and a second detector, wherein:
When the systematic error of the Fizeau interferometer to be calibrated is calibrated, the relative positions of the point diffraction interferometer and the Fizeau interferometer to be calibrated are kept unchanged, and short coherent light generated by a light source is connected into the Fizeau interferometer to be calibrated by using an optical fiber; then, the light beam sequentially passes through the polarization beam splitting prism and the collimating lens to form collimated light to be incident on the standard spherical lens, the last surface of the standard spherical lens is a ziming surface, and part of the light beam is returned to form reference light in a primary path; the transmitted light beam is converged on a metal reflecting film layer of a point diffraction plate of the point diffraction interferometer, and the partially transmitted light beam does not return to the Fizeau interferometer to be calibrated any more because the point diffraction plate is obliquely arranged relative to the optical axis;
Short coherent light generated by the light source enters the second converging mirror through the optical fiber and the optical fiber coupler, the converging light is diffracted at a pinhole of the point diffraction plate, high-quality spherical waves are generated, and the high-quality spherical waves enter the Fizeau interferometer to be calibrated through the standard spherical mirror, so that measuring light is formed;
the reference light and the measuring light sequentially pass through a collimating mirror, a polarization beam splitter prism, a second reflecting mirror and a second imaging mirror in the Fizeau interferometer to be calibrated and then reach the second detector; and heterodyne phase shifting is carried out on the second detector, and a plurality of frames of interferograms are collected, so that the system error calibration of the to-be-calibrated Fizeau interferometer is realized.
According to the technical scheme provided by the invention, the device utilizes the point diffraction interferometer to calibrate the surface shape error of the reference surface and the system error of the Fizeau interferometer, so that high-precision absolute surface shape data of the measured element are obtained, and the limitation of standard spherical mirror surface shape processing precision on the system measurement precision is broken.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a high-precision error calibration device for a Fizeau interferometer according to an embodiment of the invention;
Fig. 2 is a schematic diagram of an optical path for performing systematic error calibration by the apparatus according to an embodiment of the present invention.
Detailed Description
The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments of the present invention, and this is not limiting to the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to fall within the scope of the invention.
Fig. 1 is a schematic structural diagram of a high-precision error calibration device for a fizeau interferometer according to an embodiment of the present invention, where the device includes a light source 1, a point diffraction interferometer 2, and a fizeau interferometer 3 to be calibrated, where:
The light source 1 is used for generating short coherent light and heterodyning phase shifting;
The point diffraction interferometer 2 is used for measuring the surface shape of the reference surface of the Fizeau interferometer 3 to be calibrated and emitting a point diffraction spherical wave;
the point diffraction interferometer 2 comprises an optical fiber coupler 5, a first converging mirror 6, a second converging mirror 7, a point diffraction plate 8, a first reflecting mirror 9, a first imaging mirror 10 and a first detector 11, wherein:
As shown in fig. 1, when the surface shape error of the reference surface of the fein interferometer 3 to be calibrated is calibrated, the short coherent light generated by the light source 1 is coupled to the optical fiber coupler 5 inside the point diffraction interferometer 2 through the optical fiber 4, and then the laser is respectively incident to the first converging mirror 6 and the second converging mirror 7;
then forming convergence points at pinholes of the point diffraction plate 8, respectively diffracting to generate reference light and measuring light, wherein the measuring light is incident on a reference surface of a standard spherical mirror 12 of the Fizeau interferometer 3 to be calibrated, and the point diffraction plate 8 is positioned at a focus of the standard spherical mirror 12, so that reflected light of the reference surface of the standard spherical mirror 12 is converged on a metal reflecting film layer near the pinholes of the point diffraction plate 8, and enters the first imaging mirror 10 together with the reference light through the first reflecting mirror 9, finally low-frequency heterodyne interference is generated on the first detector 11, and then the surface shape error of the reference surface of the Fizeau interferometer 3 to be calibrated can be calculated from an interference pattern acquired from the first detector 11;
fig. 2 is a schematic diagram of an optical path for performing system error calibration by using the device according to the embodiment of the present invention, where the fizeau interferometer 3 to be calibrated includes a standard spherical mirror 12, a polarization splitting prism 14, a collimator lens 15, a second reflecting mirror 16, a second imaging mirror 17, and a second detector 18, and the method includes:
When the systematic error of the Fizeau interferometer 3 to be calibrated is calibrated, the relative positions of the point diffraction interferometer 2 and the Fizeau interferometer 3 to be calibrated are kept unchanged, and the optical fiber 13 is used for connecting the short coherent light generated by the light source 1 into the Fizeau interferometer 3 to be calibrated; then, the light beam sequentially passes through the polarization splitting prism 14 and the collimating lens 15 to form collimated light to be incident on the standard spherical lens 12, the last surface of the standard spherical lens 12 is a zimine surface, and part of the light beam is returned to form reference light in a primary path; the transmitted light beam is converged on the metal reflecting film layer of the point diffraction plate 8 of the point diffraction interferometer 2, and the partially transmitted light beam does not return to the Fizeau interferometer 3 to be calibrated any more because the point diffraction plate 8 is obliquely arranged relative to the optical axis;
Short coherent light generated by the light source 1 enters the second converging mirror 7 through the optical fiber 4 and the optical fiber coupler 5, the converging light is diffracted at a pinhole of the point diffraction plate 8 to generate high-quality spherical waves, and the high-quality spherical waves enter the Fizeau interferometer 3 to be calibrated through the standard spherical mirror 12 to form measuring light;
The reference light and the measuring light sequentially pass through a collimating mirror 15, a polarization splitting prism 14, a second reflecting mirror 16 and a second imaging mirror 17 in the Fizeau interferometer 3 to be calibrated and then reach the second detector 18; heterodyne phase shifting is carried out on the second detector 18, and a plurality of frames of interferograms are acquired, so that the system error calibration of the to-be-calibrated Fizeau interferometer 3 is realized.
In the specific implementation, in the calibration process by using the device:
The wavefront W R (r, θ) of the reference optical path is denoted as:
WR(r,θ)＝S(r,θ)+2L(r,θ)+2nA(r,θ)+I(r,θ)
Wherein r and θ are polar components of the spatial point, respectively; s (r, θ) is the wave aberration of the illumination light path; l (r, θ) is the wave aberration of the standard spherical mirror 12 in the Fizeau interferometer 3 to be calibrated; n is the refractive index of the reference surface corresponding lens of the standard spherical lens; a (r, θ) is the reference surface shape error; i (r, θ) is imaging optical path wave aberration;
the wavefront W T (r, θ) of the measurement light path is denoted as:
WT(r,θ)＝L(r,θ)+(n-1)A(r,θ)+I(r,θ)
The interferometry result M (r, θ) can be obtained by subtracting the wavefront of the reference optical path and the wavefront of the measurement optical path, expressed as:
M(r,θ)＝WR(r,θ)-WT(r,θ)＝S(r,θ)+L(r,θ)+(n+1)A(r,θ)
The surface shape error A (r, theta) of the reference surface of the Fizeau interferometer 3 to be calibrated is obtained through calculation, and the system error W sys (r, theta) is separated according to the known lens refractive index n and is expressed as:
Wsys(r,θ)＝S(r,θ)+L(r,θ)；
the system error is the wave front error irradiated to the surface of the measured element, and can be corrected in the subsequent measurement result.
It is noted that what is not described in detail in the embodiments of the present invention belongs to the prior art known to those skilled in the art.
In summary, the device according to the embodiment of the invention has the following advantages:
1. The device can not only calibrate the surface shape error of the reference surface, but also calibrate the system error of the Fizeau interferometer;
2. The device does not need to use the measured element for in-situ detection, the measured element can be detected in batches once the interferometer to be measured is calibrated, and a high-precision measurement result is obtained through a calibration file;
3. The calibration process of the device only needs to be carried out twice, no mechanical moving parts exist, and the requirement on environmental stability is reduced.
The foregoing is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions easily contemplated by those skilled in the art within the scope of the present invention should be included in the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims. The information disclosed in the background section herein is only for enhancement of understanding of the general background of the invention and is not to be taken as an admission or any form of suggestion that this information forms the prior art already known to those of ordinary skill in the art.
Claims (2)
1. A high accuracy error calibration device for fizeau interferometer, characterized in that the device includes light source, point diffraction interferometer and fizeau interferometer that waits to mark, wherein:
The light source is used for generating short coherent light and heterodyning phase shifting;
the point diffraction interferometer is used for measuring the surface shape of the reference surface of the Fizeau interferometer to be calibrated and emitting a point diffraction spherical wave;
The point diffraction interferometer comprises an optical fiber coupler, a first converging mirror, a second converging mirror, a point diffraction plate, a first reflecting mirror, a first imaging mirror and a first detector, wherein:
When the surface shape error of the reference surface of the Fizeau interferometer to be calibrated is calibrated, short coherent light generated by the light source is coupled to an optical fiber coupler in the point diffraction interferometer through an optical fiber, and then laser is respectively incident to a first converging mirror and a second converging mirror;
Then forming convergence points at pinholes of the point diffraction plates, respectively diffracting to generate reference light and measuring light, wherein the measuring light is incident on a reference surface of a standard spherical mirror of the Fizeau interferometer to be calibrated, and the point diffraction plates are positioned at focuses of the standard spherical mirror, so that reflected light of the reference surface of the standard spherical mirror is converged on a metal reflecting film layer near the pinholes of the point diffraction plates, and enters the first imaging mirror together with the reference light through the first reflecting mirror, finally low-frequency heterodyne interference is generated on the first detector, and then the surface shape error of the reference surface of the Fizeau interferometer to be calibrated can be calculated from an interference pattern collected on the first detector;
The to-be-calibrated Fizeau interferometer comprises a standard spherical mirror, a polarization beam splitter prism, a collimating mirror, a second reflecting mirror, a second imaging mirror and a second detector, wherein:
When the systematic error of the Fizeau interferometer to be calibrated is calibrated, the relative positions of the point diffraction interferometer and the Fizeau interferometer to be calibrated are kept unchanged, and short coherent light generated by a light source is connected into the Fizeau interferometer to be calibrated by using an optical fiber; then, the light beam sequentially passes through the polarization beam splitting prism and the collimating lens to form collimated light to be incident on the standard spherical lens, the last surface of the standard spherical lens is a ziming surface, and part of the light beam is returned to form reference light in a primary path; the transmitted light beam is converged on a metal reflecting film layer of a point diffraction plate of the point diffraction interferometer, and the partially transmitted light beam does not return to the Fizeau interferometer to be calibrated any more because the point diffraction plate is obliquely arranged relative to the optical axis;
Short coherent light generated by the light source enters the second converging mirror through the optical fiber and the optical fiber coupler, the converging light is diffracted at a pinhole of the point diffraction plate, high-quality spherical waves are generated, and the high-quality spherical waves enter the Fizeau interferometer to be calibrated through the standard spherical mirror, so that measuring light is formed;
the reference light and the measuring light sequentially pass through a collimating mirror, a polarization beam splitter prism, a second reflecting mirror and a second imaging mirror in the Fizeau interferometer to be calibrated and then reach the second detector; and heterodyne phase shifting is carried out on the second detector, and a plurality of frames of interferograms are collected, so that the system error calibration of the to-be-calibrated Fizeau interferometer is realized.
2. The high precision error calibration device for a fizeau interferometer of claim 1, wherein during calibration with the device:
The wavefront W R (r, θ) of the reference optical path is denoted as:
WR(r,θ)＝S(r,θ)+2L(r,θ)+2nA(r,θ)+I(r,θ)
Wherein r and θ are polar components of the spatial point, respectively; s (r, θ) is the wave aberration of the illumination light path; l (r, theta) is wave aberration of a standard spherical mirror in the Fizeau interferometer to be calibrated; n is the refractive index of the reference surface corresponding lens of the standard spherical lens; a (r, θ) is the reference surface shape error; i (r, θ) is imaging optical path wave aberration;
the wavefront W T (r, θ) of the measurement light path is denoted as:
WT(r,θ)＝L(r,θ)+(n-1)A(r,θ)+I(r,θ)
The interferometry result M (r, θ) can be obtained by subtracting the wavefront of the reference optical path and the wavefront of the measurement optical path, expressed as:
M(r,θ)＝WR(r,θ)-WT(r,θ)＝S(r,θ)+L(r,θ)+(n+1)A(r,θ)
Obtaining a reference plane surface shape error A (r, theta) of the Fizeau interferometer to be calibrated through calculation, and separating out a system error W sys (r, theta) according to a known lens refractive index n to be expressed as:
Wsys(r,θ)＝S(r,θ)+L(r,θ)；
the system error is the wave front error irradiated to the surface of the measured element, and can be corrected in the subsequent measurement result.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410076355.2A CN118089534A (en) | 2024-01-18 | 2024-01-18 | High-precision error calibration device for Fizeau interferometer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410076355.2A CN118089534A (en) | 2024-01-18 | 2024-01-18 | High-precision error calibration device for Fizeau interferometer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN118089534A true CN118089534A (en) | 2024-05-28 |
Family
ID=91141403
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202410076355.2A Pending CN118089534A (en) | 2024-01-18 | 2024-01-18 | High-precision error calibration device for Fizeau interferometer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN118089534A (en) |
-
2024
- 2024-01-18 CN CN202410076355.2A patent/CN118089534A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR100225923B1 (en) | Phase shifting diffraction interferometer | |
| JP3237309B2 (en) | System error measuring method and shape measuring device using the same | |
| EP1682851B1 (en) | Reconfigureable interferometer system | |
| CN106768280B (en) | Multi-wavelength lens-free Fourier transform digital holography-based vibration detection device | |
| WO2022241875A1 (en) | Transmissive and reflective digital holographic microscopy system | |
| US6704112B1 (en) | Application of the phase shifting diffraction interferometer for measuring convex mirrors and negative lenses | |
| US6876456B2 (en) | Absolute calibration of optical flats | |
| JPH1163946A (en) | Methods for measuring shape and manufacturing high-precision lens | |
| CN110631510B (en) | High-precision angle measuring device and method based on Michelson structure | |
| CN110160443B (en) | Optical fiber point diffraction interference device and method for transient three-coordinate measurement | |
| CN109458959B (en) | Variable-inclination-angle phase-shift grazing incidence interferometer measuring device and method | |
| CN114396887B (en) | Dynamic interferometer and measuring method | |
| JP2008107144A (en) | Apparatus and method for measuring refractive index distribution | |
| CN118089534A (en) | High-precision error calibration device for Fizeau interferometer | |
| JPH10160582A (en) | Interferometer for measuring transmitted wave front | |
| US11333487B2 (en) | Common path mode fiber tip diffraction interferometer for wavefront measurement | |
| CN104748946B (en) | Optical fiber point-diffraction interferometer optical fiber diffraction reference wavefront bias measurement method | |
| JPH07229721A (en) | Device for generating aspherical wave and method for measuring aspherical shape | |
| JPH116784A (en) | Device and method for measuring shape of aspherical surface | |
| JPS6365882B2 (en) | ||
| CN118129627B (en) | High-sensitivity mirror deformation measurement system and method based on speckle interference | |
| CN217716309U (en) | Thickness detection equipment of transparent film | |
| CN116608792B (en) | Wavefront interferometry system and method | |
| JPH11311600A (en) | Method and apparatus for measuring refractive index distribution | |
| JPH10232115A (en) | Measurement for interference of lens |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |