CN1016274B - Zaser contourgraph of contactless high resolution scanning type - Google Patents
Zaser contourgraph of contactless high resolution scanning typeInfo
- Publication number
- CN1016274B CN1016274B CN 86106872 CN86106872A CN1016274B CN 1016274 B CN1016274 B CN 1016274B CN 86106872 CN86106872 CN 86106872 CN 86106872 A CN86106872 A CN 86106872A CN 1016274 B CN1016274 B CN 1016274B
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- China
- Prior art keywords
- object lens
- laser
- polarization direction
- contourgraph
- light
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- Instruments For Measurement Of Length By Optical Means (AREA)
- Length Measuring Devices By Optical Means (AREA)
Abstract
The present invention relates to a novel contactless high-resolution scanning type laser contourgraph. Two coaxial laser beams of which the polarization directions are orthogonal are used as two arms of an interferometer, one laser beam is made into a parallel beam with a greater diameter by using the method of the present invention, the other laser beam is converged into a small light spot, and the two laser beams fall on a measured surface together. The measurement resolution can reach 1A; when the measured surface has high reflection performance, the measurement resolution can reach 0.1A. The contourgraph is suitable for measuring the fine surface contour shapes of various metals and non-metals, for example, the high-grade film-plated optical surfaces, metal reflectors of large-power laser devices, reflecting surfaces of X-ray astronomical devices, silicon sheet material surfaces, very large scale integrated circuits, fine standard blocks of checking contourgraphs, etc.
Description
The invention belongs to the laser measurement technology field.Measure the method and apparatus of fine surface contour shape with differential principle of interference of polarized light and photosignal phase measurement.
Because the development of high-performance optics equipment, ray equipment (as laser weapon and χ gamma ray object measurement mechanism) and ic industrial technology, new, the contactless contour measuring method of high resolving power becomes exigence, and the researcher is also quite a lot.Relevant in this respect article has:
(I) Z.F.Zhou(Zhou Zhaofei) " PTB Mitteilungen " 94.1/84 " untersuchungen ueber ein Fotoelektrl-sches Interferenz-Messmikroskop mit Zweifreq-ueuzlaser Zum Messen Von Feinstrukturen ".
（Ⅱ）G.Makosch，B.Drolliner《Applied Optles》1984.12.“Surface profile measurment With a scanning differential ac Interferometer”
(III) C.W.See, M.Vaez, and H.K.Wikramasinghe " Applied Optics " 1985.8. " Scanning differe-ntial phase contrast optical microscop:appl-ication to surface studies " " Applied Optics " 1 August 1985/Vol.24, No.15 etc. all have report.
But these research work all have obvious deficiency, and subject matter is:
1 differential interferometer can only be done relative measurement-can only compare the height difference of two little luminous point projections place, can not measure true profile.Often light beam just partly utilizes objective aperture because of causing enough little luminous point, and lateral resolution is low.
2 can only be applicable to a certain specific surface configuration or very little measurement range, and limitation is very big.
The manufacturing accuracy of 3 pairs of equipment itself requires too high, is difficult for stablizing, and is difficult to reach high resolving power.
4 use maximum contact synthesis measuring profilometer devices now, can scratch fine surface during measurement, for the surface that requires not allow to stay scuffing, then can't measure with instrument with contacts.
Zaser contourgraph of contactless high resolution scanning type provided by the invention can be measured the true shape of fine surface profile, has differential interferometer again and vibrates, disturbs insensitive advantage to external world, and manufacturing accuracy own is not also had excessive demand.Its resolution and signal to noise ratio (S/N ratio) are high.The meticulous profile of energy measurement Any shape, and contactless, can not scratch measured surface fully.Be applicable to and measure various metals and nonmetallic fine surface contour shape.As senior coated optics surface, the metallic mirror of high power laser, the reflecting surface of the astronomical device of X ray, silicon sheet material surface, VLSI (very large scale integrated circuit), the meticulous calibrated bolck of check and correction contourgraph etc.
Fig. 1 is the Zaser contourgraph of contactless high resolution scanning type structural representation
(1), laser tube.(2), slide.(3), (3 ') polaroid.(4), (17) lens.(5), (18) photoelectric tube.(6), (19) amplifier.(7), (10) icelandspar birefringece crystal.(9), (12) catoptron.(11), lens.(13), semi-permeable and semi-reflecting mirror.(14), λ/4 slides.(15), object lens.(16), measured piece.(20), phasometer.(21), register.
The present invention is a kind of polarized interferometer that utilizes differential principle. With polarized light splitting device laser is divided into mutually perpendicular two bundles in polarization direction, a branch of conduct makes to converge on the object lens rear focus with reference to arm, becomes the bigger collimated light beam ν of diameter behind object lens1 Other is light beam ν2As gage beam, before entering object lens, remain diameter and can be full of the flat of objective aperture Row light is converged to minimum luminous point through object lens and falls on the measured surface. This two-beam center is coaxial. Because the hot spot of reference arm light beam to the tested surface be very greatly for tiny uneven reactionless, and measure hot spot very little (can reach 1 μ m), be fine to 1 so can measure with the horizontal resolution capability of 1 μ m in short transverse
(dust), limiting resolution can reach 0.1
The surface profile shape. Because light beam ν1And ν2Be coaxial, optimally utilized that differential interferometer is anti-interference, the characteristics of vibrationproof superior performance, for phase measurement provides the high s/n ratio condition.
Below be to describe in detail:
As Fig. 1 and Fig. 2 (being the following partial enlarged drawing of crystal among Fig. 1 (10)).Their frequency of the laser beam laser beam of quadrature (or become after treatment) that laser instrument (1) penetrates the polarization direction quadrature is respectively ν
1And ν
2Tell the sub-fraction orthogonal beams as the reference signal with slide (2).The frequency of this reference beam is above-mentioned ν
1And ν
2Beat frequency, i.e. ν
Ginseng=ν
1-ν
2Major part then sees through slide (2) and is folded to icelandspar birefringece crystal (10) through catoptron (9), is broken down into two light beams according to the polarization direction.A branch of polarization direction of central authorities focuses on the focus in image space of object lens (15) through convergent lens (11) perpendicular to paper, is mapped on the measured piece surface by becoming parallel beam behind the object lens (15), and this a branch of light is just as the reference arm of interferometer.Another Shu Guang is folded to left by icelandspar birefringece crystal (10), and the polarization direction is parallel to paper, is mapped to semi-permeable and semi-reflecting mirror (13) after catoptron (12) reflection, and on the object lens (15) of transferring then, it is coaxial with reference arm to come back to central authorities.Because this Shu Guang does not produce convergence without lens (11), reaches object lens (15) so remain directional light, is converged to then on the measured piece surface and (sees accompanying drawing 2 for details).This a branch of light is exactly the gage beam of interferometer, or is called measuring beam.Such light path arrangement makes measuring beam can be full of aperture of objective lens, thereby obtains minimum convergence luminous point.Because reference beam cross section diameter quite big (and can regulate on demand in 40 microns to 10 millimeters scopes) forms a large spot on the measured piece surface, make the trickle fluctuations of fine surface virtually completely can ignore, and measuring beam is forming a minimum hot spot (its diameter at 1 micron to 5 micrometer ranges) on the test specimen surface to the influence of interferometer.Any horizontal direction size in test specimen surface greater than the small fluctuations of this hot spot all with measured come out (the horizontal direction size also can be found less than the fluctuations of two to three times of hot spots).The later course of work is: above-mentioned measuring beam and reference beam are reflected by measured surface, again through object lens (15), λ/4 slides (14) etc. turn back to icelandspar birefringece crystal (10), because they pass through λ/4 slides twice, the polarization direction is all turned over 90 ° separately, measuring beam passes through always when passing through icelandspar crystal (10) again, and reference beam is folded to the right side (Fig. 1).So just avoid reflected light to get back to laser instrument and caused job insecurity.This two-beam is combined into a branch of through icelandspar birefringece crystal (7) (its length is the twice of icelandspar birefringece crystal (10)) more again.Behind the polaroid (3 ') of 45 ° of placements, interfere, converge to photoelectric tube (18) by lens (17).Here the signal frequency that records should be:
(ν
1-ν
2) ± d ν=ν
Ginseng± d ν
In the formula d ν be measure luminous point when the measured piece along continuous straight runs moves with the lip-deep uneven and caused Doppler shift of bob of measured piece.Because this invention is used to measure the fine surface contour shape, ± d ν is everlasting in the half wavelength (λ/2), and maximum several half-wave wavelength are so compare and measure signal ν with phasometer (20)
GinsengThe reference signal ν that ± d ν and photoelectric tube (5) are sent here through amplifier (6)
GinsengPhase place.If tested plane is a desired smooth, d ν=0 then, phasometer (20) is output as a fixing level, register (21) straight line that draws.In fact as long as that fearness has only 1 on the measured piece surface
Even 0.1
The uneven output level that also will cause change, draw contour shape by register instrument or computing machine.If variation exceeds half wavelength (or the more segmentation of phasometer retaining range) then recording curve is a serrate, each sawtooth is half wavelength (λ/2) or thinner phase place score retaining range.Can restore with computer coordinates is true shape.
The invention has the advantages that and utilized the differential interferometer principle and cause coaxial measuring beam and reference beam, make anti-vibration, air temperature and current change performance more to be better than differential interferometer.This invention is extremely insensitive with the vibration interference of instrument itself to external world, still can stablize, measure exactly the only test specimen contour shape of 1nm that rises and falls when measured piece approximates 80nm with respect to the object lens Oscillation Amplitude.Simultaneously the objective table guide rail that installs itself there is not the accuracy requirement of undue strictness, because the not straight first-order error that do not cause of guide rail.In addition, when measuring operation, do not require very strict with test specimen level-off (level-off for present high-resolution profile device-, be a pretty troublesome problem) as Talystep.
Embodiment
Zaser contourgraph of contactless high resolution scanning type provided by the invention can be made of conventional optics, machining, and make model machine in the laboratory, makes a large amount of tests and contrast work:
1 pair of high power laser cavity mirror of making by oxygen-free copper (can be used for laser weapon).Soft again because of its surperficial dead smooth material, can only measure indistinct contour shape with existing best Talystep contourgraph and change, and stay cut, can not obtain true measurement result.And with apparatus of the present invention with 1
Profile variations be amplified to 2mm, measure contour curve clearly, do not contact the test specimen surface.
2 once measured by monocrystalline silicon and make the contourgraph calibration standard piece that is used for integrated circuit industry, measure its contour shape details, and had found that original calibrating has error.Because this device is to be scale with laser, as long as the lasing light emitter frequency stabilization reliably just need not to calibrate with other standard again.
3 once measured by glass and made the meticulousst level contourgraph check and correction reference block, and numerical value meets fine, and deviation has only 2 percent.Gauging error less than standard itself.
Claims (1)
1, a kind of Zaser contourgraph of contactless high resolution scanning type [1], use the polarized light splitting device beam split, and under object lens, form reference arm and gage beam and by extracting behind the laser beam expander than reference signal mutually, it is characterized in that laser being divided into mutually perpendicular two bundles in polarization direction with polarized light splitting device, a branch of reference arm as interferometer converges at the object lens top, becomes the big and disposable parallel beam v of diameter behind object lens
1, and another bundle v
2As gage beam keeping parallelism light before entering object lens, become minimum luminous point to drop on the test specimen surface through object lens centre convergence, this two-beam center is coaxial, and laser instrument (1) penetrates the laser beam of polarization direction quadrature or becomes the laser beam of quadrature after treatment, and their frequency is respectively v
1And v
2, tell the conduct of sub-fraction orthogonal beams than phase reference signal with slide (2), the frequency of this reference beam is above-mentioned v
1And v
2Beat frequency, i.e. v
Ginseng=v
1-v
2Major part then sees through slide (2) and is folded to icelandspar birefringece crystal (10) through catoptron (9), be broken down into two light beams according to direction of polarized light, a branch of polarization direction of central authorities is perpendicular to paper, focus on the focus in image space of object lens (15) through convergent lens (11), be mapped on the measured piece surface by becoming parallel beam behind the object lens (15), this a branch of light is just as the reference arm of interferometer, another Shu Guang is folded to left by icelandspar birefringece crystal (10), the polarization direction is parallel to paper, after catoptron (12) reflection, be mapped to semi-permeable and semi-reflecting mirror (13), transfer then on the object lens (15), it is coaxial with reference arm to come back to central authorities, and this Shu Guang does not produce convergence without lens (11), remain directional light and reach object lens (15), converged to then [2] on the measured piece surface.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 86106872 CN1016274B (en) | 1986-10-27 | 1986-10-27 | Zaser contourgraph of contactless high resolution scanning type |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 86106872 CN1016274B (en) | 1986-10-27 | 1986-10-27 | Zaser contourgraph of contactless high resolution scanning type |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN86106872A CN86106872A (en) | 1988-05-11 |
| CN1016274B true CN1016274B (en) | 1992-04-15 |
Family
ID=4803396
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 86106872 Expired CN1016274B (en) | 1986-10-27 | 1986-10-27 | Zaser contourgraph of contactless high resolution scanning type |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1016274B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1313815C (en) * | 2004-11-17 | 2007-05-02 | 中国科学院上海光学精密机械研究所 | High-resolution narrow-linewidth long-aging detection device |
| CN103697825B (en) * | 2013-12-30 | 2017-01-18 | 中国科学院西安光学精密机械研究所 | Super-resolution 3D laser measurement system and method |
| CN104457581B (en) * | 2014-08-28 | 2017-03-22 | 深圳奥比中光科技有限公司 | Overall Z-axis displacement measuring system |
| CN105651193A (en) * | 2016-04-01 | 2016-06-08 | 芜湖哈特机器人产业技术研究院有限公司 | Device and method for detecting formed oil pipes |
-
1986
- 1986-10-27 CN CN 86106872 patent/CN1016274B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| CN86106872A (en) | 1988-05-11 |
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