TWI358528B - Interferometry systems and methods - Google Patents

Description

1358528 •, s IX. DESCRIPTION OF THE INVENTION: TECHNICAL FIELD OF THE INVENTION The present invention relates to an interferometric system and method. [Prior Art] The interferometric optical technique has been widely applied to the surface profile (s u r f a c e p r 〇 f i 1 e s) of a precision optical element (precision 〇 p t i c a 1 c 〇 m ρ e n e n t s). For example, when measuring the surface profile, an interferometer can reflect one of the test wavefront and the reference surface reflected by the test surface (tes1: surface). A reference wavefront is combined 'as such to form an optical interference pattern. The spatial variation in the intensity profile of the optical interference pattern is relative to the phase difference (phas ediff ence s ) between the combined test pre-guided wave and the reference pre-guided wave, the phase difference is Caused by changes in the contour of the test surface associated with the surface to be tested. A phase-shifting interferometry (PSI) can be used to accurately determine the phase differences and the calibration profy of the test surface. The surface rim measurement of the test surface is relative to the surface profile of the reference surface, which is ideally set (eg, flat (f 1 at)) or the known margin of production. 6961-PF; Ahddub 6 1358528 (tol erances). Under the action of P SI, the optical interference pattern is recorded relative to each phase displacement between the pre-test guided wave and the reference leading wave, such that a series of optical interference patterns are generated and these optical interference patterns Sustainable optical interference (eg, at least a half cycle from constructive to destructive interference). These optical interference patterns can define a continuous density value for each spatial position of the pattern, wherein the continuous density value includes a sinus〇idal dependence of the phase-shifts ′ The phase-offset is equal to the phase difference between the combined test pre-guided wave and the reference pre-guided wave and for the spatial position. With the use of conventional numerical techniques, the phase offset of each spatial position can be extracted via sinusoidal correlation of density values, thereby providing the contour of the test surface associated with the reference surface. This numerical technique is generally called phase

Phase-shi f t i ng algorithms. The phase shift in pSI can be produced by changing the length of the measuring surface to the length of the optical path of the interferometer as compared to the length of the reference surface to the optical path of the interferometer. For example, the reference surface can be moved relative to the measurement surface. On the other hand, the phase shift can be set to a constant, which is the non-zero optical path obtained by the change measurement and the reference pre-wave. The latter application is well known for its wavelength tuning PSI (wavelength tuning PSI) and has been described in the related art ', for example, U.S. Patent No. 4,594, 〇〇3 to G. E. Sommargren. 1057-6961-PF; Ahddub 7 1358528, Fizeau Interferometer is one of the features that can be used to characterize the surface of a test object. Interferometer. In many embodiments, for later analysis, one of the time periods during which a computer captures a continuous frame of interference pattern of one of the detectors. The phase shifting of the object surface is based on the mechanical translation or wavelength modulation of the reference surface. For example, 'the time modulation is not required for the Fizeau interference pattern. In some cases of (temporal modulation), the pro file surface is a high-speed measurement that can be used to adjust dynamically actuated parts. Although the Twymann-Green interferometer geometries in these different kinds of technologies include spatial phase shifts or phase shifts based on polarization, these techniques are still required for reference and object beam reflections. (reference and object beam ref lections) for separation. However, whether using space or polarization, the common-path characteristics of the large-aperture Fizeau interferometer cannot be easily referenced to objects and objects. The beam is reflected for separation. SUMMARY OF THE INVENTION 1057-6961-PF; Ahddub 8

1358528 In general, a first feature of the present invention includes an interferometer including a main cavity and an auxiliary reference surface, a main partially reflective surface, the partial reflective surface defining a major surface and a test surface The interferometer is designed to direct the input electromagnetic main portion to the main cavity, and to be guided by one of the input electromagnetic radiation, and is reflected by the auxiliary reference surface, wherein the first portion of the main portion of the cavity is via The main reference shot, one of the main parts of the main cavity, passes through the surface and is reflected by the test surface. The interferometer is designed to reflect the electromagnetics of the surface, the main reference surface, and the auxiliary reference surface. The detector detects an interference pattern with another electromagnetic radiation guide. Another feature of the invention is the inclusion of a method comprising: directing a major portion of the input electromagnetic radiation to an interference cavity, wherein one of the main portions of the main cavity is the first main cavity A primary reference surface is reflected by a second portion of the main cavity that passes through the primary reference surface and is fired by a test. The auxiliary reference surface, one of the input electromagnetic radiations, is guided to reflect from an auxiliary reference surface from one of the interferometers. The input reflected from the face, the primary reference surface, and the auxiliary reference surface is directed to a multi-element detector, thereby inducing interference with another electromagnetic radiation to form an interference pattern. Embodiments of the apparatus and/or method of the present invention may include one or more of the features. The interferometer, the cavity includes an auxiliary part to refer to the table radiation, and the main reference on the main empty surface is to dry the test table radiation guide. The main part of the method is reversed by the surface of the main part, This produces a test gauge electromagnetic radiation between τ to 1057-6961-PF; Ahddub 3 1358528. The method of the present invention can include determining surface profile information, interference patterns associated with the test surface, based on the interference pattern. It is formed by the input electromagnetic reflection reflected by the test surface main surface and the auxiliary reference surface. A second interference pattern is formed by electromagnetic light reflection reflected by the main reference surface and the auxiliary reference surface, and the test surface is The reflected electromagnetic radiation does not reach the multi-element detector. In one embodiment, the primary reference surface can be a partially reflective surface. In some embodiments, the second portion of the major portion of the main cavity is through the primary reference surface and is reflected by the test surface. The surface area of the auxiliary reference surface is smaller than the surface area of the main reference surface. The auxiliary reference surface is flat and the primary reference surface is curved: the device of the present invention may further include a preventive device, and electromagnetic radiation from the test surface may be remote from the multi-component detector in a selective manner of the preventive device. For example, the apparatus of the present invention can include an opening 1 between a primary reference surface and a test surface. The device of the invention may further comprise a multi-component detector and an electronic control

The device, where 'under the interference pattern, the electronic controller is designed to use L to determine the surface of the test surface. Under the interference pattern formed via electromagnetic radiation, the electromagnetic radiation is reflected by the test surface, the primary reference surface, and the auxiliary reference surface, and the electronic controller is designed to determine surface contour information of the test surface, and a second interference The pattern is formed by the electromagnetic radiation reflected by the primary &lt; reference surface and the auxiliary reference surface, and the electromagnetic radiation reflected by the test surface does not reach the multi-component measurement..." "A auxiliary reference surface is relative to the interferometer One optical axis is tilted to form a complex spatial carrier stripe in the pattern of the dry, 1057-6961-PF; Ahddub 10 1358528. The apparatus of the present invention further includes a positive parent phase detection system, and the quadrature phase detection system includes In some embodiments, the auxiliary reference surface is disposed on a converter, and the converter is designed to change the length of the optical path extending to the multi-element detector, the optical path length is the multi-element The detector is applied to the electromagnetic radiation reflected by the auxiliary reference surface. The interferometer can include a folding lens (for example: a mirror or an edge) With a frame, the folding lens is designed such that the main reference surface is facing up. The portion of the frame is designed to support the test surface. The interferometer includes a beam splitter (eg, a non-polarized beam splitter or polarization) The beam splitter is used to separate the main part of the input electromagnetic radiation from the auxiliary part of the incoming electromagnetic radiation. The interferometer may comprise one or more imaging lenses, and the imaging lens images the test surface in a multi-component debt Above the detector, the t-setting of the present invention may further comprise a light source 'the light source is used as a wheeled electromagnetic radiation (for example, a laser). The interferometer is a Fizeau interferometer, a Michelson interferometer, an interferometer or a Miru Interferometers. In a particular embodiment, the method of the present invention can be implemented by embodiments of the apparatus. In other advantages of the invention, embodiments of the apparatus and method can provide a plurality of Fizeau interferometers, In terms of environmental sources (eg vibration), these Fizeau interferometer pairs can be mechanically stable and relatively insensitive, and when When the instrument is used to measure between a test part or different parts, the environmental sources of these uncertainties are caused to cause the movement of the surface inside the interferometer. In terms of stability and environmental effects, 1057-6961-PF; Under the influence of Ahddub 11 1358528, the interferometer system can have better reliability and more precise. 'And, in addition, the single-picture using an interference pattern replaces multiple writings, by implementing The interferometer system included in the example can perform surface wheeling measurement because it is necessary to have (4) in a multi-faceted system. In terms of distance, the time required for single-screen measurement execution technology: More surface technology is less. In addition, the use of single-screen technology reduces the need for moving parts (eg, converters used for phase shifting), thereby reducing the cost of the interferometer system. A single facet measurement using a Fizeau interferometer is still executable with no optical elements between the reference surface and the test surface $πt, A. Therefore, the source of the error caused by the measurement using the Fizeau interferometer can be reduced compared to the system in which the optical element is included in the measurement beam path. In terms of commercial availability (c〇mmercia Uydan, • the features of the present invention can be achieved with appropriate and simple changes to the interferometer system in use. For example, commercially available crimes Interferometers may include the use of one of a few additional components to assist the mirror, and the price of these additional components is not too expensive. Compared to conventional phase shifting systems, devices and methods in some embodiments of the present invention may include The mechanical phase shift interferometer system, the mechanical phase shift interferometer system can effectively improve the properties. For example, the interferometer system can include an auxiliary mirror that is placed on a converter so that it can be in Fizeau The mechanical phase is displaced on the outer side of the cavity. It is made up of 1057-6961-PF; Ahddub 12 is the auxiliary point in the large opening system, so the above system is only far less than the special phase displacement of the reference mirror. The converter can be implemented with an auxiliary mirror to simplify the orthogonality relatively: in the case of the lzeau interferometer system, 'Using the pole u parent phase to measure the interference The system can be obtained from the non-known work. This Fizeau., and in the surface of the reference t; iZeaU work cavity beam is polarized in the year of the mud and the test piece (for example: a quarter glass B does not In the case where there is any fragment of the additional knives, the symmetry θ, ai can still be performed. In addition, after using the enthalpy, the phase measurement is performed. The phase measurement is performed. In a special embodiment, among the interference patterns, the straight lL 戟 and the stripe can be introduced to the .r ′′, and the interference pattern is used to drain the shaft and the mirror beam. The instrument replaces the reference mirror. In addition, in the case of &quot;'forming', it is possible to adjust the direction to the null position when measuring with the reference mirror. The above and other objects, features, and advantages of the present invention will become more apparent and understood <RTIgt; Complex F i zeail interference (Fizeau interferometers), these Fizeau interferometers are enhanced by the inclusion of an auxiliary reference mirror (auxiliary reference mirror). Since the reference surface of Fizeau is not required 13 1057-6961-PF; Ahddub 1358528 • ( F i zeau' s ref erence) and any additional elements introduced between the complex test surface (tes1; surf aCes) or changing the alignment between the above surfaces. (al ignment), the auxiliary reference mirror is Various interference quantities, interferometry techniques are used to complete. For example, Lu's auxiliary reference mirror is designed to introduce complex carrier fringes into a Fizeau interference pat tern, so that a single interferogram surface formed by the test surface can be utilized (single The interferogram frame produces a characteristic {characterization) of the test surface. As another example, quadrature phase measurements can be easily accomplished using polarization by introducing any additional components between the Fizeau reference surface and the complex test surface of the Fizeau interferometer. Instantane 〇us quadrature phase measurement). Since any optical components in the measurement beam path under the Fizeau interferometer are sources of first order errors in the measurement process, Under the influence of an auxiliary reference mirror, these techniques do not cause any substantial loss in system accuracy. In addition, the auxiliary reference mirror can also be mechanically phase-shifted in a Fizeau interferometer without causing movement of the reference or test surface during the process. The environmental stability associated with a stationary Fizeau cavity can improve the accuracy and repeatability of the system. Referring to FIG. 1 for the month of β, an interferometry system (interferometry 1057-6961-pp; Ahddub 14 1358528 system) 100 is used for one reference surface 141 and one test object 190 for a reference lens (reference 〇ptic) i4 ( For example, an optical plane is used to measure the optical interference generated by one of the surface 151 of one of the test surfaces 191 and one auxiliary reference mirror ( auxi liary reference mirr〇r) 150, wherein The auxiliary reference mirror 150 is substantially smaller than the reference lens 140. The reference surface 141 defines a Fizeail cavity with the test surface 191, such as the cavity 101 shown in FIG. The interference measurement system ι〇〇 Lu includes a mount 192 that is used to correlate with the auxiliary reference mirror 1 50! 1 Test object 1 9 〇 support. In addition, the interference measurement system 100 further includes a beam splitter 120. The beam splitter 120 separates a light source (i ght source) 10 (for example, an iaser diode, a HeNe laser, or the like) into a two-component optical component (component). Beams), the two component beams are respectively guided relative to the input beam and the transmitted components of the input beam, and the transmitted component is guided toward the Fizeau cavity 101, and the reflected component is It is directed toward the auxiliary reference mirror 150. In addition, the beam splitter 120 can combine the light reflected from the auxiliary reference mirror 150 via the Fizeau cavity 101 and direct the combined light to the pixel detector.

(pixelated detector) 160 (for example: CCD camera) ° Furthermore, the interference measurement system in Figure 1 includes the complex optical 1057-6961-PF; Ahddub 15 1358528 -- • components And beam shaping optics. The optical component includes a collimating lens 115, and a beam shaping lens package including lenses 130, 132. Before the light is incident on the beam splitter 120, the correcting lens 115 can collimate the diverging light from the light source 110. The beam reflected by the beam splitter 120 can be enlarged by the lens 130' 132 before the light comes into contact with the reference lens 140. In general, in addition to the correction lens ^5 and the lenses 130, 1 3 2, the interference measurement system 1 〇 〇 also includes other optical components. During operation, the light source 11 is illuminating the beam splitter 丨2〇. The beam splitter 120 transmits illumination of a portion of the surface ι 51 of the auxiliary reference mirror 15 , and uses a beam splitter to direct a portion of the illumination toward the F i zeau cavity 1 〇 1 . This illumination is partially transmitted by the reference lens 140 and reflected by the test surface 191 of the test article 19〇. In addition, a portion of the illumination from the beam splitter 12 and incident on the reference lens 140 is reflected via the reference surface 141. The illumination system reflected by the reference surface 14 and the test surface 91 is propagated along the common path (c〇ffim〇n path) of the beam splitter 120 from the F丨zeau cavity to the pixel detector. Detector 1 6 〇. In addition, a portion of the illumination reflected by the surface 151 of the auxiliary reference mirror i 5 is permeable to the pixel detector 16 via the beam splitter 12 (eight) from the auxiliary reference mirror 15 , the reference surface 141 and the test surface 191 and the interference of the guided wave (WaVefr〇ntS) incident on the pixel detector 16〇 results in a stripe pattern having a varying intensity. 1057-6961-PF; Ahddub 16 1358528 The interference s-test system 100 includes an electronic controller (electr〇nic C〇ntr〇ller) 180, which is in communication with the pixel detector i6〇. The electronic controller 180 includes a frame grabber for storing images detected by the pixel detector i6. The electronic controller 丨8〇 analyzes the image stored by the image capture card and provides the user with information about the test surface 191 based on the analysis result. In general, the 'auxiliary reference mirror 15 is a flat and directional mirror' that assists the reference mirror 1 5 〇 surface 1 5 丨 can be reflected relative to the reference surface 141 (path 〇f illun] inati〇 n) is tilted so that carrier fringes can be directed to one of the interference patterns formed by the measurement and wavefronts of the pixel detector 160. In general, under the action of the tilt mode described above, the fringes can be guided to the auxiliary reference mirror, and the guided waves are reflected by the reference surface 141 before being reflected by the reference surface 141. Among the patterns. In some embodiments, the 'carrier stripe may have a period id' for directional positioning of the auxiliary reference mirror 150. This period is substantially relative to the position of the pixel detector 16 〇 3 or 3 More than (detector 〇rpi X e 1 s) (for example: about 5 or more, about 8 or more, about 1 〇 or more than 1 、, about 2 〇 or 2 〇 More than one detector pixel). The auxiliary reference mirror 1 5 〇 can be placed on an adjustable mount to facilitate the adjustment of the direction of the auxiliary reference mirror 150. 1057-6961-PF Ahddub 17 1358528 When using the interferometric measuring system 1 〇0 to determine a surface prof ile of the test surface 19 1 , it comprises two steps: no interferometer measurement without the test surface 191 and having Measurement of the test object. For each measurement step, the interference phase (9 and signal modulation) of the image data of each detector pixel is electronically controllable. The device 1 800 can be determined. In one of the ways in which the phase information is input through each measurement step, the method is to perform a spatial Fourier transform of the interference pattern, and then the frequency is In the frequency domain, a carrier fringe frequency is discriminated by a digital filter. On each pixel, an inverse transform of the filtered spectrum is provided. Phase 0 and Signal Modulation # » by Macy's Two • Dimensional Fringe Pattern Analysis,” Appl, Opt., 22' pp. 3898-3901 (1983) as an example of 'exposing the use of Fourier transforms Phase extraction methods, all of which have been incorporated by reference. Based on the following calculations, the surface height profile of the reference surface 141 is related to each measurement. Phase information. As shown in Figure 1, when the interference measurement system 1 〇〇 does not contain the reference lens 14 0, the interference amount The complex reflectivity measured by System 1 is based on η, which is 1057-6961-PP; Ahddub 18 1358528 « - _ Amplitude effective reflectivity of auxiliary reference mirror ''internal amplitude reflectivity', ί is the effeet of transmission through the beam shaping, lens, and reference lens 140. In the case where all the constants of the cavity length and the phase change relating to the reflection effects are ignored, the measured phase can be measured for each pixel. Expressed as: (1) where, e.=arg(ri) (2) Θ; =arg(iV2) (3) where η =4^1 βχρ〇' θι) (4) Lu r2=T^exp (/02) (5) ί = ν^χρ(!·θ,) (6) Therefore Θ;=2Θ,+Θ2· (7) The phase value (phase vaiues) associated with the surface sufficiency can be based on Θ, = 2k\ ( 8 ) θ2 = 2kh2 ( 9 ) Since k = 2π/λ (10) 1057-6961-PF; Ahddub 19 1358528 and λ is the source wavelength measurement signal modulation Expressed as: ma=ivt4ra (11) where 'r is the fringe visibility coef f icient'. This fringe visibility coefficient is assumed to be independent of the field position (fi eld position), and the fringe visibility coefficient is over time. For the constant value, the interference pattern obtained by the test object 1 90 included is known as the ray tracing test table. 191. Referring to the general path of the light reflected by the surface U1 (c〇mm〇n path), the phase measurement of each pixel thereof can be expressed as: θδ = θζ-θ, (12), where θ 'ζ=2θ, +θζ_ (13) and the phase heart returned by the Fizeau cavity itself is ez=arg(z) (14) so z = (r2 + r3). (15) Measurement signal Modulated to MB: 2VT (16) where Z = |z|2 For the phase term θ3 of each pixel relative to the surface contour information of the test surface 191, the known &amp; ρ phase term % is by the following Measurement phase and signal modulation 1057-6961-PF; Ahddub 20 8 1358528 • · ψ 9 was decided. The composite reflectance r of the Fizeau cavity 101 is measurable for each pixel via measured data according to the following equation: (η) The reflectivity of the reference surface 141 is determined by the equation ( Η) and equation (5) to get ——(18) φ Therefore, from equation (15), we know that r3=z-r2, (19) one can be expressed as 6 =f^^[Mfiexpd — ζ·~)-岣], (20) The complex argument is the desired phase: _ θ3 = axg[MB exp( i θΒ-ΐθΑ)~ ma] + θ2 (2J) φ on the above reference surface The profile /?2 is known to determine the surface profile of the test surface 1 丨 independent of the effect of the optical system via equation (21). In a particular embodiment, the reflectivity of the reference surface 141 is required to be reduced. In these examples, 'antireflection (AR) coating is applied over the reference surface U1, thus reducing FiZeau II. The filling rate of the cavity 1〇1, and the effect of the optical path instability (err〇rs) between the reference surface 141 and the surface 1 51 of the auxiliary reference mirror 150 can be Being lowered 1057-6961-PP; Ahddl〇h 1358528 a · ·» ^ low. For example, the above technique is for reference surface 141, auxiliary, compared to the measurement error that may occur between the first measurement and the second measurement under unstable environments. The "inner" cavity is formed by the surface 151 of the reference mirror 150. The drift (dr ift) is more sensitive. In general, the high fill rate strip between m3 (high-finesse fj*inges) is the most sensitive. As the amplitude of the Fizeau cavity 101 decreases, the anti-reflective coating is applied to the reference surface 141. The amplitude of the stripe printed by it is reduced. For example, if =0. 5 % and 怂 = 4 % 'for an inner cavity (for example: by reference surface 141, auxiliary reference mirror 150 The resulting errors of the drift formed by the surface 151 are reduced by three factors. On the other hand or in addition, since the interference measurement system 1 can be designed to be sufficient Rigidity, first measurement and second time The phenomenon of internal cavity drift associated with a certain feature portion can be substantially avoided. In a particular embodiment, by the action of one of the interferometer systems, the first time The 'internal cavity' stability between the measurement and the second measurement is monitorable, and regardless of whether a test object (b) is positioned in the interferometer system, the interferometer system It is possible to monitor the interference pattern associated with the inner cavity. For example, an annulus can be placed in the field of view of the pixel detector 160, and the pixel detector 160 is only for the reference 1057. ^6961-PF; Ahddub 22 8 1358528 Test surface 141 is tested and the reflection r3 of test surface 191 is excluded. As shown in Fig. 2, one of the loops of some embodiments is available in Fizeau jade chamber 1〇 One of the holes 1 (aperhre) 21 () is formed. For example, "if the test object 1 90 is larger than the angle of view of the interference measuring system 1" in the use of masking for part of the test surface Way The reflection from the test surface can be excluded by using the lower H hole 21 0. For each measurement, one of the loops included in the interference measurement system 100 is a relative tip to the inner cavity. , tilt (ti It), piston (pist〇n) to make a decision. Equation (21) is corrected by measuring drift vaiues: θ3 = argfM, exp(θβ - / θ, + ζ θ^;) - Μ,] + θ2, (22) , 0 is: the phase change (phaSe change) between the first measurement and the second measurement and the pixel position related to one shift in the inner working chamber. Please refer to Fig. 3, the interference measurement System 3 〇〇 can be used to profiling a CUrVed test surf ace of a test object 39 0 . The interferometric measuring system 30 0 includes a reference object 310 having a curved (eg, spherical) reference surface 311 'and using a reference The object 31〇 and the test object 390 define a Fizeau cavity (Fizeau cav i ty ) 3; 0 Γ. The beam shaping lens of the interference measuring system 300 also includes an additional lens (add iti ona 1 1057-6961-PF; Ahddub 23 1358528 lens) 320 * j: ψ , , /, A 'this additional lens 320 is used For focusing on the beam splitter 1 2 0 from the beam splitter, the focus can be normalized.

It is incident on the curved surface of the test object # q Q η &gt; , I lr 390 (curve(j 5111^3^). In addition to the different geometry of the U cavity 3〇1, the interference measurement糸The system 0 入 入 η 入 入 入 全 全 全 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉 干涉Techniques may also be useful for phase information. For example, 'some embodiments may utilize polarization to obtain phase measurements from a single interference® pattern' thereby providing phase quadrature k to the interference pattern Between the orthogonal polarizations (orthogonal p〇iarizati〇ns). Figure 4 shows an interferometric measurement system 400' This interferometric measurement system 40 uses polarization to perform phase quadrature measurements (phase quadrature) The interference measurement system 400 includes a polarization beam splitter (PBS) 420 that separates incident illumination from the source 110 into a complex component. Beam, these component beams have In the orthogonal linear polarization states, a beam of light is reflected by the surface 151 of the auxiliary reference mirror 150, while other beams are reflected by the reference surface of the Fizeau cavity 110, the test surface. A quarter wave plates 410 are positioned in the path of the beams so that the polarization state of each beam can be rotated by 90 degrees. Thus, the beam originally transmitted via the PBS 420 can be The ray is reflected and the beam that is initially reflected and immediately reflected by the Fizeau cavity 101 is reflected by PBS 420 1057-6961-PF; Ahddub 24 1358528. PBS 420 will assist the reference mirror 150, Fizeau cavity 101 The reflected illumination is directed toward a detector assembly 401 'where' the detector assembly 4 (n includes pixel detectors 460, 470 and unpolarized light | splitter (non -p)侦测iarizing beam splitter 435. The detector assembly 401 also includes a plurality of lenses 430, 440, 445' for focusing and correcting illumination from the PBS 420. A portion of the illumination from the PBS 42 is directed toward the pixel detector 47A by reflection from the non-polarized beam splitter 435, and a portion of the illumination is passed to the pixel detector 460 using the non-polarized beam splitter 435. A linear polarizer (iinear p〇iar^zer) is positioned between each pixel detecting thief 4 60 0, 407 and the non-polarized optical splitter 4 3 5 . In particular, a polarizer 462 is positioned in front of the pixel detector 46, and another polarizer 472 is positioned in front of the pixel detector 47, wherein the polarizers 462, 472 are Oriented at 45 degrees with respect to the transmission axis of the PBS 42 (transmissi〇n_axis), thereby ensuring that the prime detectors 46〇, 47〇 can be reflected by the auxiliary reference mirror 150, the Fizeau cavity 1〇1 The illumination is sampled. A quarter slide is positioned between polarizer 472, non-polarized beam splitter 435, and a 90 degree phase shift can be introduced to the polarizer using the orientation of the slide. Among the transmitted polarization states. Therefore, in terms of the interference phase of the interference pattern on each of the detector pixels of a pixel detector, the interference phase is offset by 9 degrees and relative to the other pixel detector. The interference phase of the interference pattern on the pixel. 1057-6961-PF; Ahddub 8 1358528 The signal under quadrature can be used for fast modulation and phase measurement, which assumes constant density offset/ The DC is known. Therefore, 'measured intensity obtained by a camera that does not have one object is gA=lf+MAcos(QA) (23). The measured density obtained by the device is g^=lf+MAsm{QA) (24)

Quad a jDC 9 MQA)=^i~ (25) SA~h e+r-zff+wr)2 (26) In order to determine 'whether using highly tilted or rapid movement for auxiliary reference When the mirror is operated, it can create a separate measurement, so that the average is adjusted for the modulation term 沁c〇s (eJ and the blood team). At R. Smy the and R.

Moore, Proc. Soc. Phot. Opt. Eng. 429, 16 (1983), in an alternative embodiment, at least one having an additional phase shift is added. Under the action of the camera, the sufficient information provided can be solved simultaneously for modulation, average density and phase. In other embodiments, the polarization-encoded reference and measurement beams can project a plurality of images (muitiple images) to a single phase detector detector in various phase shift modes (sing 〗 e camera detector), this way with Kujawinska et al. in "Spatiai 1057-6961-PF; Ahddub 26 8 (28) (27) 1358528 and signal modulation can be expressed as: M2 = [7 (g2-g4)- (g〇-g6)f+f8g3-Wg5)]2 162 On the other hand or in addition, other methods for determining the phase and modulation of the interference by means of an auxiliary reference mirror can be employed. For example, the size of the opening of the Fizeau cavity is sufficient to capture the reflection of the entire test surface using a large reference optic (eg, the size of the reference surface 141 is the same or greater than The size of the test surface 19i is locally achievable. In fact, since the interference measurement system is designed to characterize large test parts, a relative The type and heavy reference lens is processed. Since the Fizeau aperture is not placed on the auxiliary mirror with the same size requirements and the auxiliary mirror is used as the reference lens 14 The manner in which the small auxiliary mirror is translated to perform mechanical phase shifting has a number of advantages. Thus, it can be seen that the converter is of a smaller size and simpler construction than one of the transducers used in the reference lens 140. Furthermore, since there is a physical distance (phys(d) dlstance) between the auxiliary reference mirrors, the auxiliary reference mirror can take a more effective way to self-test the objects. The isolation 疋 so that the t Flzeau cavity can have a better 1057-6961-PF during the data acquisition period; Ahddub 28 1358528 * • · In some embodiments as shown in Fig. 6, the 'interference measurement system can be designed to look upwards (upffard_) 00king) type system, thereby simplifying the gripping operation of the test part. For example, the interference measuring system 6〇〇 includes one. Mirror stack (fold mirror) 610, this folding mirror 61〇 beam splitter 120 is located on the reference object 640, between the test part 69〇. The folding mirror 610 directs the illumination from the beam splitter ι2〇 along a vertical path such that the illumination is illuminated onto the reference object 64〇 on the horizontal plane. Under the action of the test surface 691 associated with the reference surface 461, the test part 691 can be placed relatively easily on a frame (m〇unt) 692, whereby the frame 6 9 2 to maintain a small separation between the test surface 691 and the reference surface 601. In the above configuration, since the gravity automatically aligns the test part to the reference object 64, all of the flat parts of any size need not be aligned with the top and the tilt described above. In general, the above embodiments include the use of an auxiliary mirror and a Fizeau interferometer, and the phase and magnitude techniques of an auxiliary mirror are equally applicable to other types of interferometers. For example, the phase and amplitude technique using an auxiliary mirror is applicable to a conventional interference microscope objective [e.g., Mirau, Michelson or Linnik. Conventional Interference The microscope objective can include an auxiliary reference mirror that is relatively smallly modified with standard geometry. 1057-6961-PF; Ahddub 29 8

It is to be understood that the scope of the present invention is not intended to be While the present invention has been described in terms of the preferred embodiments of the present invention, any one skilled in the art will be able to make changes and refinements, as defined by the scope of the patent application. The figure shows a diagram of an embodiment of an interferometry assembly comprising a Fizeau interferometer and an auxiliary reference mirr〇r Enhanced by the "(10) interferometer. Figure 2 shows that the interference measurement assembly of Figure 1 can be modified to have a narrow annular aperture that blocks the line of sight for the object ( View) and thus may be retained for a portion of a single-surface reflection from a Fizeau reference. Figure 3 shows a diagram of an embodiment of an interference measurement assembly. The assembly includes a spherical Fizeau cavity and an auxiliary reference mirror. Figure 4 shows an embodiment of an interference measurement assembly. In the drawing, the interferometric measuring component comprises a Fizeau interferometer which uses an auxiliary reference mirror to enhance the Fizeau interferometer, and the auxiliary reference mirror utilizes polarization (ρ ο 1 arizati ο n+) It is provided as an instantaneous quadrature phase measurement 1057-6961-PF; Ahddub 30 1358528 • * * - *. Figure 5 shows a diagram of an embodiment of an interference measurement component. The interference measurement assembly includes a Fieze interferometer that enhances the Fizeau interferometer with an auxiliary reference mirror, and the auxiliary reference mirror uses mechanical phase shifting. It is known that 1 is used as a phase measurement. Figure 6 shows a diagram of an embodiment of an interference measuring assembly including an upward looking-looking Fizeau interferometer (upward-looking)

Fizeau interferometer), this upward looking Fizeau interferometer is enhanced with a secondary reference mirror for the Fizeau interferometer. Element Symbol Description] 100~ Interference Measurement System; 101- ~Fizeau Cavity; 110~ Light Source, 115-'Corrected Lens; 120- Beam Splitter 130, 132~Lens; 140- Reference Lens 9 141- 'Reference Surface 150- auxiliary reference mirror; 151--surface; 160~ pixel detector; 180-, electronic controller; 190~ test object» 191- - test surface; 192~ frame t 210- •• opening; 300 - Interference measurement system; 301--Fizeau cavity; 310~ Reference object* 9 311-reference surface; 320~ lens* 3 90--test object; 400-interference field measurement system; 401--detector component; 1057-6961-PF; Ahddub 31 1358528 420 ~ polarized beam splitter; 430, 440, 44 5 ~ lens 435 ~ non-polarized beam splitter; 460 ~ pixel detector; 462, 472 ~ polarizer 472 ~ Polarizer; 510~converter; 610~folding mirror; 641~ reference surface; 6 91~ test surface; 470~pixel detector; 5 0 0 ~ interference measurement system; 6 0 0~ interference measurement system; 640~ reference object; 6 9 0 ~ Test parts; 6 92~ rack.

1057-6961-PF; Ahddub 32

Claims (1)

135852 094108007 No. 7 modified on November 7, 100. Patent application scope: 1. An interference measurement system includes: an interferometer comprising a main cavity and an auxiliary reference surface, the main cavity including a part a reflective surface for defining a primary reference surface and a test surface. The interferometer is designed to direct a major portion of the input electromagnetic radiation to the main cavity for one of the input electromagnetic radiation The auxiliary portion is guided to be reflected by the auxiliary reference surface, wherein a first portion of the main portion in the main cavity is reflected in the main cavity via the main reference surface The first portion of the main portion is passed through the main reference surface and reflected by the test surface, the interferometer is further designed to guide the test surface, the main reference surface, the auxiliary reference surface reflected by the electromagnetic radiation And an interference pattern formed by the interference between the multi-component detector and the other electromagnetic radiation guide, wherein the auxiliary reference surface is Oblique state, so that the multi-element detector Ik π, the reference surface from the primary to the secondary reference anti _ exit surface of the non-parallel path of the electromagnetic radiation. 2·If the application scope of Shen 4 is 帛! The interferometric measuring system of the item, wherein the main cavity defines a Fizeau cavity. 3. If you apply for a patent scope! The interferometric measuring system of the present invention, wherein the optical path of the second portion between the primary reference surface and the test surface does not have a beam shaping lens. The interferometric measuring system of claim 1, wherein the product is smaller than a surface of the main reference surface. 4. The surface area of the auxiliary reference surface is as claimed in the patent application. 1057-6961-PF1 33 100 years η月7曰Revision replacement page 5. If Shenqing patent scope is the first! The interferometric measuring system of the item, wherein 'the auxiliary reference surface is flat' and the main reference surface is curved. 6. The interferometric measuring system of claim i, further comprising - (d) device - the electromagnetic (four) from the test surface can be remote from the multi-element detector in an alternative manner of the preventive device . 7. The interference measurement system of claim 1, wherein the multi-component detector and an electronic controller are further configured to design the electronic controller based on the interference pattern. To determine the surface contour information of the test surface. 8. The interference measurement system of claim 7, wherein the electromagnetic radiation is from the test surface, the primary reference surface, and the interference pattern formed by the electromagnetic radiation. The auxiliary reference surface is reflected by the 'electronic control H' which is designed to determine the surface rim of the test surface, and the two interference patterns are shaped by the electromagnetic radiation reflected by the primary reference surface and the auxiliary reference surface. And the electromagnetic radiation reflected by the test surface does not reach the multi-component detector. 9. The interferometric measurement system of claim 1, wherein the auxiliary reference surface is tilted relative to an optical axis of the interferometer to form a complex spatial carrier stripe in the interference pattern. S10. The interference measurement system of claim i, further comprising: a quadrature phase detection system, wherein the quadrature phase debt measurement system comprises the multi-element detector. 11. The interferometric measuring system of claim i, wherein the interferometer comprises a folding lens and a frame, the folding lens is set to 1057-6961-PF1 34 November 7 correction Replacement page 135852|〇94_7 is used to bring the primary reference surface up, and part of the machine to support the test surface. 1 2. In the amount of interference as recited in claim 1, the interferometer includes a beam splitter that separates the main portion of the input electromagnetic radiation from the input electromagnetic spoke portion. 1 3 _ In the interference amount described in claim 1, the interferometer includes one or more imaging lenses, and the imaging test surface is imaged on the multi-component detector. 14. The interference measurement as described in claim 1 includes a light source 'the light source is the input electromagnetic radiation. j 15. The auxiliary reference surface according to the interference amount described in claim 1 Is connected to a converter, the switch is used to change the optical path length of the input electromagnetic radiation, and the input is reflected to the multi-component detector 1 via the auxiliary reference surface. 6. The interference measurement method comprises: Directing a major portion of the input electromagnetic radiation to a dry cavity, wherein one of the main portions of the main cavity is reflected by a primary reference surface of one of the main cavities, one of the main portions The second part is reflected by the primary reference surface; for the input electromagnetic light-assisted reference surface, the test surface, the primary reference surface and the auxiliary are applied to an auxiliary reference surface from the interferometer The frame is a design measuring system, and the device is used for the auxiliary measuring system for shooting, and the lens is included in the measuring system. The measuring system, the converter is designed into one of the electromagnetic radiation related devices. The first part is the surface in the main cavity and is guided by the measuring line, by reflection; and the reference surface is 1057-6961-PF1 35 100 years 1 month 7th correction replacement page 135852^ 〇94] 〇8〇〇7^ reflection. The input electromagnetic radiation is guided to a multi-element detector to thereby guide the gate with another electromagnetic radiation; the interference of B forms an interference pattern, and the auxiliary reference surface is inclined, so that the auxiliary reference surface is inclined In the multi-component detection &amp; the primary reference surface and the path of the electromagnetic radiation reflected by the auxiliary reference surface are non-parallel. 1 7. The method of interferometry as described in claim 6 of the patent scope further includes determining the surface rim information associated with the test surface based on the interference pattern.馨1 8. An interferometric measuring system comprising: an interferometer comprising a main cavity and an auxiliary reference surface, the main cavity comprising a main reference surface and a test surface, wherein the interferometer is designed to Directing the main portion of the input electromagnetic radiation to the main cavity, under which the auxiliary portion of the entrained electromagnetic radiation is guided for reflection through the auxiliary reference surface, wherein the main cavity a first portion of the main portion is reflected by the primary reference surface, and a second portion of the main portion in the main cavity _ passes through the main reference surface and is reflected by the test surface, the main portion not contacting the Auxiliary reference surface, and the auxiliary portion does not contact the main reference surface or the test surface, the interferometer is further designed to guide the electromagnetic radiation reflected by the test surface, the main reference surface, and the auxiliary reference surface to a multi-element detector for interfering with another electromagnetic radiation guide to form an interference pattern; and an electronic controller based on the interferogram Below, the electronic controller is designed to determine the surface contour information of the test surface, the interferogram 1057-6961-Pfi 36 135852 鼋 _ (10) 〇 7 No. 1 11 November 7 曰 corrected replacement page 135852 鼋 _ (10) Case No. 7 is the main reference surface of the input electric field reflected by the test table and the test element detector. The surface is formed by the primary reference surface radiation, and the electromagnetic radiation reflected by the reflective surface of the auxiliary reference surface and the auxiliary interference surface two interference pattern are not formed by the electromagnetic radiation. The interferometric measuring system of claim 18, wherein the primary reference surface is a partially reflective surface. The interferometric measuring system of claim 19, wherein the second portion of the main portion in the main cavity passes through the main reference surface and is reflected by the test surface . 21. The interferometric measuring system of claim 18, wherein the dry/stepper is a Fizeau interferometer, a Michelson interferometer, a Linnik interferometer or a Mirau interferometer. 2 2. An interference measurement method, comprising: directing a main portion of the input electromagnetic radiation to a main cavity of an interferometer, wherein the first portion of the main portion in the main cavity Reflected by a primary reference surface of the main cavity, the second portion of the main portion of the main cavity being reflected by a test surface; for guiding the auxiliary reference surface of the input electromagnetic projection Thereby, thereby reflecting the auxiliary reference surface from one of the interferometers; guiding the input electromagnetic radiation reflected by the test surface, the main reference surface and the auxiliary reference surface to a multi-component detector, Thereby forming an interference pattern by interference with another electromagnetic radiation guide arch; and 1057-6961-PF1 37 1358528. No. 094108007 100 years 11 based on the interference pattern formed by the electromagnetic radiation Testing surface surface information of the surface, the electromagnetic radiation surface, the primary reference surface, and the auxiliary reference surface. The second interference pattern is defined by the primary reference surface and the auxiliary The emission of electromagnetic radiation being formed, and the test does not reach the surface emissivity of the multi-element detector, which is not in contact with the main portion of the auxiliary section is not the primary reference surface or reference surface in contact with the test surface. ® 23. In the interference described in claim 22, the second portion of the main portion is reflected by the primary test surface. On the 7th of the revised replacement page, it is determined that the reflection is reflected by the test, and the electromagnetic surface is reflected by a reference surface, and the auxiliary measurement method has its reference surface and is 1057-6961-PF1 38