CN1759296A - Full-filled optical measurements of surface properties of panels, substrates and wafers - Google Patents
Full-filled optical measurements of surface properties of panels, substrates and wafers Download PDFInfo
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Abstract
Techniques and systems for using optical interferometers to obtain full-field optical measurements of surfaces, such as surfaces of flat panels, patterned surfaces of wafers and substrates. Applications of various shearing interferometers for measuring surfaces are described.
Description
Technical field
The application requires the right of priority of U.S. Provisional Application of submitting on January 28th, 2,003 60/443,342 and the U.S. Provisional Application of submitting on January 29th, 60/443,329 and 2,003 60/443,804.Incorporate whole disclosures of above-mentioned three applications into this paper as the application's a part at this with way of reference.
Background technology
The application relates to the surface slope in flat board, substrate and the wafer or the measurement of other surface topology character, more specifically, relates to be used for the optical technology and the system of these measurements.
When the relevant light beam of two or more segment spaces at least was overlapping, optical interference will take place.Various optical interdferometers utilize the interference of two coherent light beams to produce the interference pattern of interference fringe, and interference fringe is that the difference by the optical path length of two interfering beams causes.Use the information that is included at least one interfering beam of in the optical measurement value, extracting exactly for one of this interference, to characterize the surface nature of being studied, for example surface topology character.
Summary of the invention
The application comprises optical technology and system, and it utilizes optical interference measurement to obtain patterning and the non-intrusion type of non-patterned surface in various devices and the structure, the measurement of the whole audience.Described embodiment comprises and utilizes the optical shearing interferometer mensuration to the patterning on various surfaces and the measurement of non-patterned surface shape.The application has also described the optical interferometry technology of the non-patterning rear surface of irradiate wafer or substrate, and wherein said wafer and substrate have the front surface of patterning.If reasonable in design, can provide the measurement of full field value on surface in real time based on the surface monitoring system of a technology in the disclosed optical technology.In addition, such surface monitoring system can provide on-site supervision to the wafer in the processing.
In one embodiment, for example, utilize detecting light beam to shine a surface to be measured, to produce the reflected probe beam that has distortion in that cause by described lip-deep irradiation area, the reflected wavefront with basic homogeneous wave front.Guide described reflected probe beam by an optical shearing interferometer instrument, an optical interference pattern between duplicating with another that obtains described reflected wavefront and described reflected wavefront, another copy space of wherein said reflected wavefront the shear distance that has been shifted.Then, regulate described another phase shift between duplicating of described reflected wavefront and described reflected wavefront, from described optical shearing interferometer instrument, to obtain a plurality of phase-shifted interference pattern of different phase shifts.Handle described interference pattern then, to obtain the surface slope information on the irradiation area described in the described surface to be measured.
In another embodiment, with the rear surface of support component contact wafer, to support described wafer.On the described wafer front surface opposite, be shaped on pattern with described rear surface.Shine described rear surface with detecting light beam, to produce the reflected probe beam that has distortion in that cause by the irradiation area on the described rear surface, the reflected wavefront.Produce an optical interference pattern with described reflected probe beam then, wherein said interference pattern comprises owing to the interruption that exists support component to cause on described rear surface or discontinuous (discontinuities).In the processing of described optical interference pattern, use interpolation algorithm, so that interpolation is carried out having the interference fringe that causes on the zone of described interruption in described rear surface, thus interference pattern feature that obtain only to cause, in the described irradiation area by described rear surface.Then, the described interpolated interference pattern from described rear surface is handled, with the surface slope of relevant position on the described front surface that obtains described wafer.
Perhaps, available other measurement and disposal route come the above-mentioned interpolation algorithm of surrogate data method in handling, with the data in the above zone, described rear surface that obtains to be occupied by described support component.For example, under the situation of not using interpolation algorithm, handle interference pattern, with the surface slope of relevant position on the described front surface that obtains described wafer from described rear surface.Then, the angle orientation that changes described the above wafer of support component at least once, thereby obtain at least one another reflected probe beam from identical detecting light beam, thereby obtain another optical interference pattern.Then, described another interference pattern from described rear surface is handled, with the surface slope of relevant position on the described front surface that obtains described wafer.Then the surface slope that obtains from the different interference patterns of described wafer different angles location is compared.Be filled in the missing data that the place, a position in the interference pattern is found, this is to realize by the data of utilizing position described in another interference pattern that obtains at place, different angles location.
The application has also described in order to improve measurement, uses the technology of interference pattern in shearing interferometer with different shear distance.In one embodiment, for example, shine surface to be measured with detecting light beam, thereby produce that cause by this surface, as to have a distorted wavefront new light beam with basic homogeneous wave front.Guide described new light beam by the optical shearing interferometer instrument, the optical interference pattern between duplicating with another that obtains described distorted wavefront and described distorted wavefront, described another copy space of wherein said distorted wavefront the shear distance that has been shifted.Then, regulate described shear distance to obtain the optical interference pattern of different shear distance.Then the described interference pattern of different shear distance is handled, to extract described lip-deep information to be measured.
In the superincumbent example, two interference patterns with two different shear distance can be subtracted each other, thereby produce a differential interference pattern, the corresponding new shear distance of this differential interference pattern, this new shear distance equals the poor of described two different shear distance.This technology can be used for obtaining the data of short shear distance, and may be difficult to obtain with given shearing interferometer.
The application has further described some shearing interferometers, and these interferometers are different from coherent gradient sensing (CGS) system of surface measurements.Compare with CGS, these non-CGS shearing interferometers may have some advantage in concrete the application.
In accompanying drawing, embodiment and claim, these and other embodiment, example and modification thereof and advantage will be described particularly.
Description of drawings
Fig. 1 shows a kind of system, and it has one according to the shear embodiment of the invention, that be used for surface measurement.
Fig. 2 shows an interference pattern, with the explanation phase-shifting technique.
Fig. 3 and Fig. 4 show two coherent gradient sensings (CGS) system that is used for surface measurements.
Fig. 5 A and Fig. 5 B show two kinds of exemplary phase-shifting techniques among the CGS.
Fig. 6 A, 6B, 7A, 7B, 7C, 8,9,10A, 10B, 11A, 11B and 11C show the example of non-CGS shearing interferometer, and these interferometers are suitable for coming surface measurements according to the technology that present patent application is described.
Figure 12 shows exemplary general arrangement, and it is used for measuring with optical mode the rear surface of wafer, and die support contacts with the rear surface at this.
Figure 13 shows an example, and wherein the rear side of wafer is to be supported by the die support that three asymmetric manners are located, and makes it possible to repeatedly measure wafer with different angle orientation, thereby directly collects the data on whole wafer surface.
Embodiment
The optical shearing interferometer instrument is on the cross-directional of the wave front direction of propagation, and the wave front of being out of shape for light beam same common produces the wave front of duplicating of two spatial displacement, and they are interfered.For example, can use horizontal and radial-shear interferometer.The interference of duplicating between the wave front of spatial displacement can produce interference pattern, and it has represented the space distribution of slope in the wave front.This class interferometer has been carried out optical differential (differentiation) to wave front in essence.In some example with the optical mode surface measurements that the application describes, at least one optical shearing interferometer instrument can be used to the optical measurement surface,, uses the collimated probe beam irradiating surface that is.Shearing interferometer can be designed to from detecting light beam pass the surface optical transmission or from detecting light beam by the optical reflection of surface reflection, produce the shear interference pattern.Then, the shear interference pattern is processed to obtain surface, slope, curvature and other surface topographical information.For example, can obtain the surface topology of surperficial whole shape and the microcosmic surface character (nanotopography) of surface local shape from shearing interferometer.Measurable surperficial example includes but not limited to, plane in various plates and dish, various substrate and wafer, integrated electronic circuit, integrated optical device, photoelectric circuit and MEMS (micro electro mechanical system) (MEMs), flat panel display systems (for example, LCD and plasma display) and mask and film and the graticule.
Utilize the optical shearing interferometer mensuration, have certain advantage with the optical mode surface measurements.For the patterned surface with various microstructures (for example mask substrate of the wafer of patterning and patterning), the optical shearing interferometer mensuration may be a kind of effective survey instrument.In addition, on-site supervision surface nature during the optical shearing interferometer instrument is used in device fabrication, on wafer scale, for example curvature and related stress, measured value can be used for dynamically controlling processing conditions and parameter.As an example, because the self-reference of optical shearing interferometer instrument (self-referencing) character, the measurement of optical shearing interferometer instrument and operation generally can significantly not be subjected to the influence of translation of rigid body and rotation.Like this, be basically perpendicular to the surface or measure measured wafer or device, can't influence measurement result with low incident angle guiding detecting light beam.By displacement or shearing wave front, the optical shearing interferometer instrument is measured the distortion of a point of wave front with respect to another point, and both are sheared distance separately, that is, and and the distance between two interference of same wave front are duplicated.Therefore in this sense, the optical shearing interferometer instrument is a self-reference, has improved its insensitivity or vulnerability to jamming to the change of measured wafer or device.This opposing to change may be favourable, and particularly the execution of Ce Lianging is in production environment or at the scene, (for example, deposits in Processing Room) in specific technological process, and in these places, separating vibration has very big difficulty.
Comparatively speaking, many non-shearing interferometers produce the wavefront interference of topology or pattern (surperficial absolute altitude), are based on from the distorted wavefront of specimen surface reflection with from the optical interference between the reference wave front of known reference surface reflection.It may be invalid using this non-shearing optical interdferometer to come the measuring element patterned surface, because under many circumstances, the wave front of patterned surface, uneven relatively or scattering is left in reflection, can not leave the wave front generation coherent interference of reference surface with reflection.In addition, patterned surface may have the reflectivity properties of fundamental difference, and for example, some zone of patterned surface is compared with other zone or the reference surface of patterned surface, may high absorption survey wavelength.Under these and other situation,, may be difficult to untie and explain the interferometric images that produces by the non-shearing interferometer of this class because there is a large amount of patterns.
Another feature of shear interference mensuration be wave front by optical differential, and this optical differential is recorded in the shear interference pattern.Therefore, only, just be enough to calculate curvature from the wave front slope meter to carry out single derivative operation (derivative operation) from the data of shear interference pattern.This has reduced operand in the process of handling interference data, therefore reduced data processing time.And, because the shear interference measuring method provides whole audience interferometry data, therefore () method for example, 3 points, the shear interference measuring method can be utilized the more data point for example to utilize conventional capacitance probe to come some points of surface measurements topology than other method.Compare with the method that those DATA REASONING density are much lower, this higher packing density provides more accurate measurement and better resisting interference.In addition, though various laser beam flying instrument also can be used for measuring wafer bending or surface curvature, these methods are only measured radial buckling usually.The shear interference mensuration can easily be measured the surface slope on two orthogonal directionss (X and Y) in the surface, thereby the whole curvature tensor and relevant stress state of wafer or substrate can be described.
Measure in the process of patterned surface of wafer or other structure (for example mask element of patterning) using the shear interference mensuration, the wafer (for example semiconductor and the photoelectricity wafer of 200 millimeters, 300 millimeters of diameters or other wafer size) of patterning can be placed in the shearing interferometer, modes of emplacement will make the collimated probe beam reflection leave wafer surface.Shearing interferometer is used for producing two interference wave fronts from the reflected probe beam on wafer surface, and latter two interference wave front of the short-range shearing of process is similar substantially in shape.Therefore, the interference between two wave fronts can produce coherent interference.May have noise and scattering though each wave front itself of patterned surface is left in reflection, having the coherence between wave front is enough to form the interference fringe pattern that contains information, and can be explained to extract surface information.
Fig. 1 shows an embodiment of system 100, and it measures specimen surface 130 based on the optical shearing interferometer method.The light source 110 that is provided produces collimated probe beam 112, and it has basic wave front uniformly.Light source 110 can produce the radiation of wide spectral range, comprises visible and nonvisible wavelength (for example, IR and UV radiation).Light from light source 110 can be coherent light or incoherent light.Guide these detecting light beam 112 irradiating surfaces 130 to produce reflected probe beam 132.Can detecting light beam 110 be directed to surface 130 with optical element 120 (for example beam splitter), and transmit reflected probe beam 132.Shear 101, promptly the optical shearing interferometer instrument is placed in the light path of reflected probe beam 132, to produce the shear interference pattern from reflected probe beam 132.Also can utilize the oblique incidence of collimated light beam 112 to the reflecting surface 130, thereby walk around beam splitter element 120.Usually, can implement shear 101 with any shearing interferometer.In actual applications, different shear constitutions may have unique feature or attribute, therefore says that from this respect they are different each other.The example of shear 101 comprises clapboard (the Bi-Lateral Shearing Interferometer in coherent gradient sensing (CGS) system that utilizes grating to cause wave front to shear, radial-shear interferometer, the bilateral scissors shearing interferometer, United States Patent (USP) 5,710,631) and other the device, some device wherein can the application with the lower part in describe.
In measurement, use phase shift can improve the method for coming measure patterned wafers with shearing interferometer by optical reflection.Can carry out phase shift, thereby little by little regulate being separated between two movable phase interfere wave fronts, thereby can or handle position of interference fringe in the specimen surface cocycle of measuring.In one embodiment, shearing interferometer can be configured to, and obtains a plurality of phase images of patterned wafer surface, for example in 0,90,180,270 and 360 phase places of spending.Phase-moving method makes and to list " relative phase " modulation at each pixel place by calculating detector array, just can measure the slope of wave front.Phase-moving method also can provide conforming explanation to the lip-deep wave front and the specimen slope of reflectance varies, as what seen on patterned wafers.On the wafer surface of patterning, each location of pixels on the sample can come reflected light with different intensity with respect to other location of pixels.This makes the explanation of any single lateral shear interferograms all become complicated.In the shear interference mensuration, phase-moving method can improve the degree of accuracy of slope resolution, and can accurately explain the interferogram on the patterned surfaces of reflectance varies.Why this becomes possibility, in part because of measured be the relative phase of each pixel or position in the shear interference pattern, and be not only the variation of fringe intensity.
Fig. 2 shows an example measuring relative phase in the phase-shifted interference pattern.The image of the interference pattern on the left side is to collect from the patterned surface of 300 millimeters silicon wafers.Interference pattern representative is a series of, for example, and in 5 phase-shifted interference pattern one.This figure upper right portion at length shows in the part, because the patterning of wafer surface, the intensity of interference fringe is marked change between difference.Comparatively speaking, the interference fringe pattern on naked surface or the continuous surface has the fringe intensity variation of smooth and continuous.The bottom-right illustration of Fig. 2 schematically shows, and is functions of phase-shift value or angle of phase displacement at the variation of two some fringe intensity on the patterned wafer surface.Axle has the angle step of 90 degree mutually, and intensity axis has been represented whole dynamic ranges of CCD or other imaging array.By a pixel region on the point 1 corresponding wafer of left side arrow logo, reflectivity herein is higher, thereby schematically uses significantly curve representation.A pixel region on the point 2 corresponding wafers of right side arrow sign, reflectivity herein is lower, thereby schematically uses curve representation more by a small margin.If implemented phase shift, relevant important parameter is the horizontal shift with respect to another curve (putting 2 curves) of relative phase angle or a curve (for example putting 1 curve), rather than the amplitude of curve.The intensity amplitude at any set point place in a series of phase shifting interferences should be sufficiently big, so that be enough to characterize dependent phase shift.
In the enforcement of phase shift,, be included in surface slope in the phase shifting interference with accurate explanation then with phase extraction algorithms with untie a plurality of phase shifting interferences that algorithm comes the collection of pattern Processing wafer surface.Suitable phase extraction algorithms can comprise Bucket nA, nB or nC, and wherein " n " is the frame number of phase shift data collection.Except above-mentioned Bucket category-A, Bucket category-B, Bucket C class algorithm, also can be with other phase extraction algorithms.The suitable algorithm of untiing comprises minimum discontinuous (Minimum Discontinuity, MDF) algorithm and pre-service conjugate gradient (Preconditioned Conjugate Gradient, PCG) algorithm.In addition, branch cut minimum (Branch Cut Minimization) algorithm and Wa Shi modulation guiding (Tiled ModulationGuided) algorithm also can be used for handling phase shifting interference, the surface that also can untie slight patterning effectively.
In case untied interferogram,, can further improve to the explanation of the slope data that is untreated with to the derivation of curvature by coming the untreated slope data of match with surperficial polynomial expression with statistical.In order to derive pattern (or microcosmic surface situation) and curvature data, can be to the slope data applied statistics surface fitting that is untreated (comprising Jone Ke (Zernicke) polynomial expression and Legendre (Legendre) polynomial expression) of deriving from patterned wafers.
The shear interference mensuration is owing to the essence of its self-reference, thereby a character that has is that the shear interference pattern that obtains utilizes measured surface self as the reference plane substantially, calculates derivation according to this surperficial flatness.Relative data on this level or the flatness can be used in the various application, wherein can monitor or control plane height or flatness.For example, in chemically mechanical polishing (CMP) technology or other processing of surface polishing, the relative height that can monitor whole surface is determined the validity of glossing.Shearing interferometer can be used for monitoring surface planarity, and measured value can be used for controlling real-time dynamicly the polishing condition of glossing.
In certain embodiments, the shear distance between the transverse shift wave front that interferes with each other can be conditioned in measuring process, thereby improves the resolution and the degree of accuracy of data.With the interferometric images that a plurality of shear distance increments are taken the surface, the feature that can tell can be less than being used for the camera of interferometry data or the valid pixel size of imaging sensor array of taking a sample so.In addition, as the application describes below, use a plurality of shear distance highly precisely to calculate pattern or the microcosmic surface situation of being estimated the surface, rather than calculate actual surface configuration with the standard figures integral algorithm according to the relative data of geometrical calculation.
With reference to figure 1, system 100 can be used for measuring the surface of various wafers, substrate, flat board or mask element again.System 100 can measure each point in the irradiation area on the specimen surface simultaneously, to obtain flatness, surface appearance, slope, curvature and stress information.The shear interference mensuration is particularly conducive to the measured pattern surface, for example the little finished surface that often can see in semiconductor or photoelectricity wafer and substrate.Shear 101 can produce relevant on patterned surface or half-phase is done interference.
As an example, Fig. 3 shows a kind of embodiment based on system design among Fig. 1, exemplary coherent gradient sensing (CGS) system 300.Some aspect of system 300 is described in people's such as Rosakis United States Patent (USP) 6,031,611 to some extent, incorporates this patent into this paper at this with way of reference.CGS system 300 is used to collimated coherent optical beam 112 from light source 110 as the optical detection means, obtains the specularly reflecting surface 130 that surface slope and curvature information are made by any material substantially with expression.Optical element 120 for example beam splitter can be used for light beam 112 is directed to surface 130.If reflecting surface 130 is crooked, the wave front of reflected probe beam 132 just deforms, so reflected probe beam 132 obtains optical path difference or phase transformations, and described optical path difference or phase transformation are relevant with the surface configuration on measured surface 130.This system produces " snapshot " of each point in the field of illumination of surface on 1 30, therefore can obtain in the field of illumination arbitrfary point along the surface shape information of any direction.This does not just need to make detecting light beam one next some ground not inswept surperficial 130, in a sequential manner point of one-shot measurement.
The grating 140 and 150 of two Δs that are separated from each other places the path of reflected probe beam 132, thereby measures curvature with the wave front of handling distortion.Two different diffraction components generation diffraction that second grating 150 produces first grating 140, thus two diffraction components produced, utilize optical element 160 (for example lens) that two diffraction components of second grating are mixed, and interfere with each other.If use lens as optical element, have identical angle of diffraction by second grating, 150 two diffracted beams that produce and that mix by lens from second grating 150, therefore parallel to each other.The diffraction that take place by two gratings 140 and 150 have been realized the relative spatial movement between two selected diffraction components, that is, and and transversal displacement.If other grating parameter is fixed, this transversal displacement is the function of the separation delta between two gratings 140 and 150 so.More specifically, shear distance is (Δ * tan θ), and wherein θ is the angle of diffraction of two interference diffraction light beams.Therefore, grating 140 and 150 produces the wave front of two spatial displacement from the same wave front of reflected probe beam 132.Spatial filter 170 is placed with respect to optical element 160, transmitting the interference pattern of selected diffraction components, and blocks other order of diffraction from second grating 150.Usually, can select the combination of any order of diffraction (diffraction order) and the order of diffraction to be used for measuring.
Then, the interference pattern of transmission is taken by imaging sensor 180, and to produce the electric signal of representing interference pattern, wherein sensor 180 can comprise sensing pel array, for example ccd array.Signal processor 190 is handled electric signal extracting the spatial gradient of wave front distortion, and the wave front distortion is that the shape by reflecting surface 130 causes.And thereby this spatial gradient is further processed the acquisition curvature information, therefore obtains the curvature chart of field of illumination on the surface 130.On interference pattern, carry out the primary space differential and come the gauging surface gradient.If the curved transition on surface is gradual change, if promptly (out-of-plane) displacement is less than the thickness of film, line or substrate outside the plane, so this technology just can provide the accurate measured value of height of surface curvature.Other interfere measurement technique is compared with some, and this technology is insensitive to rigid motion.The details of this data processing operation has been described in people's such as the Rosakis that above quotes the United States Patent (USP) 6,031,611.In case when having finished the processing of surface slope and curvature, processor 190 further moves to calculate stress according to surface curvature.
Two gratings 140 and 150 can be any grating usually, and they can have different pitch, and each other with arbitrarily angled orientation.Preferably, two gratings are relative to each other with the equidirectional orientation, and can have identical pitch and handle with reduced data.In this case, grating orientation is to be determined by the direction of the space displacement between two selected diffraction components (" shearing ") basically, and described space displacement is that the double diffraction by grating 140 and 150 forms.
Some application may need two spaces on the different directions to shear, thereby obtains the two-dimensional slope and the curvature measurement of the whole audience.This can realize by following method, that is, when specimen surface 130 during at first direction, carry out first with CGS system 300 and measure; Then, when specimen surface 130 turns to second direction (for example, perpendicular to first direction), then carry out second and measure.
Perhaps, can implement two arm CGS systems shown in Fig. 4, it has two and overlaps independently double grating on two different directions, thereby produces interference pattern simultaneously on two different space shear directions.Therefore, can on two space shear directions, all obtain the effect that pattern, slope and curvature distribution changed along with the time.
In addition, in two gratings 140 among Fig. 3 and 150 each can be replaced by original screen panel (grating plate), this original screen panel has the crossed grating of two quadratures to realize the two dimension shearing of the system among Fig. 4, spatial filter 170 can be substituted wave filter and be replaced, this substitutes wave filter has along the extra optical aperture of x1 direction skew, thereby can optionally transmit the interference pattern of shearing along vertical direction.
In described exemplary CGS system,, just can obtain phase shift by changing two gratings 140 and 150 s' relative position.In one embodiment, can regulate two gratings 140 and 150 by the relative position in the transverse plane of x1 and x2 definition, keep simultaneously along the fixed interval between two gratings 140 and 150 of x3 direction at required constant.Fig. 5 A illustrates a kind of CGS system, locating device wherein, and for example accurately translation stage or position transducer can be used for implementing the adjusting of relative position between this grating to obtain phase shift.One in two gratings of at least one lateral attitude controller joint to cause the change of lateral attitude.Two lateral attitude controllers can engage two gratings 140 and 150 respectively to cause phase shift.In this embodiment, two gratings remain parallel to each other with fixing spacing during transverse movement.Can obtain to have a plurality of shear interference patterns of grating 140 and 150 different horizontal relative positions, with further with phase extraction with untie algorithm and handle.
Fig. 5 B shows another kind of approach and implements phase shift mechanism among the CGS.In this design proposal, two gratings 140 are fixed with 150 relative lateral attitude, and two gratings 140 and 150 keep substantially parallel.Thereby the enforcing location control gear changes two gratings 140 and 150 separation delta along the x3 direction a little with δ.The δ value is much smaller than required separation delta, so separation delta and Measurement Resolution can significantly not be subjected to the influence of little change δ.Yet the little change (δ) of this separation delta can change the whole phase place of two gratings 140 and the 150 shear interference patterns that produce.In data acquisition, regulate Δ to have different little displacements (δ) thus obtain different shear interference patterns with different phase shifts so that with phase extraction with untie algorithm and further handle.
In addition, the specimen surface 130 that can tilt with different low-angles, thus in the interference pattern of CGS system correspondence, produce different phase shifts.Can realize required phase shift with these or other phase shift mechanism.
The CGS system can design the shear distance that can dynamically arrange, thus can be as indicated above like that in measuring process, utilize different interference distances to obtain data, to improve resolution and the degree of accuracy of measuring.In CGS system (example as shown in Figure 3 and Figure 4 system), in two gratings at least one can be joined on positioning table or the alignment sensor, thereby change two relative spacings between the grating in a controlled manner, to obtain the measured value of different shear distance.
Except the CGS system, can implement shear 101 among Fig. 1 with other shearing interferometer structure.Will provide several examples below.The optical element that these shearing interferometer utilizations are different from the CGS grating produces the lateral shear between two interference wave fronts, and has their unique separately features aspect surface measurements.
Fig. 6 A and Fig. 6 B illustrate two examples of cyclic shearing interferometer (cyclic shearing interferometer).Have the detecting light beam that the parallel-plate on a half reflection surface is used for receiving and be divided into two light beams.Fig. 6 A utilizes the rotation transparent panel to produce in of two light beams and shears and variable shear distance.Fig. 6 B uses movably mirror in light path, away from zero position of shearing, shear and variable shear distance thereby produce.Make one in two reverberators translation to take place or the parallel-plate with half reflection surface is tilted a little, just can obtain phase shift.Fig. 7 A, Fig. 7 B and Fig. 7 C show) example of Jamin shearing interferometer.Fig. 8 shows the Mech-Zehnder shearing interferometer.Fig. 9 shows the Michaelson shearing interferometer.Figure 10 A and Figure 10 B show two examples of the parallel-plate shearing interferometer that can produce big shear distance.Figure 11 A, 11B and 11C show the prism shearing interferometer, and it has different prisms to produce required shearing.The structure of these shearing interferometers and operating mechanism all are known.Rotate the optical element of selecting in these interferometers and just can control and regulate shear distance.Usually, the specimen surface of inclination measurement just can obtain phase shift.In some interferometer in these interferometers, thereby an optical element in can the translation light path produces required phase shift, and need not specimen surface.
Compare with the CGS system, the homogeneity of the shear distance in these cutting systems on the whole visual fields of control is relatively easy, because the CGS system need keep grating parallel when the interval that changes between two gratings.These systems also can relatively easily obtain less shear distance, that is, usually system is located at zero state of shearing, and obtains little shear distance with rotation a little.In addition, these systems do not need to use the embedded spatial filtering mechanism at the unwanted order of diffraction of the accurate supporting mechanism that is used for grating and CGS system.Because these non-CGS shearing interferometers have above-mentioned feature and further feature, thereby in implementing some relatively more difficult application of CGS, just can carry out optical measurement to the surface with these non-CGS shearing interferometers.
Compare with CGS, top non-CGS optical shearing interferometer measuring system is because its design feature can be realized little shear distance so can dispose and be operable to.Yet the non-CGS of CGS and these system can move obtaining the effective shear distance also littler than minimum shear distance, and minimum shear distance is that the limitation by the mechanism that regulates shear distance causes.For example, can move shearing interferometer, carry out two or more measurements with shear distance with incremental difference.In can measuring in conjunction with these two, thus an effective shear distance produced with the difference between two close shear distance.Therefore, use a plurality of shear distance highly precisely to calculate estimated statement face topological (estimated surfacetopology), rather than calculate actual surface configuration with the standard figures integral algorithm according to the relative data of geometrical calculation.The detail of this technology is provided below.
Utilize high spatial frequency (or low spatial wavelength) to describe feature in shearing interferometer and can be subjected to following restriction, promptly I realizes shear distance, minimum spot size (for example, the Pixel Dimensions of imaging array) or both combinations of measuring detector.In some shear interference measuring instruments, be about as much as at critical space wavelength under two times the situation of shear distance, shear distance may be main limiting factor (magnitude of shear distance is several millimeters, and the magnitude of Pixel Dimensions is hundreds of microns or littler).Can make shear distance shorter, but this can cause the susceptibility of interferometer very little.In the shearing interferometer of reflective-mode, for example, the slope=λ of each striped/2 ω, wherein λ surveys wavelength, and ω is a shear distance.
If the structure of given shearing interferometer allows to regulate shear distance, can from same sample, collect many group interferograms by different shear distance so.In this case, if data set is paired, can make effective shear distance of two groups of data equal poor between two groups of shear distance so.
At first, consider two measurements of a data set, it has two different shear distance ω 1 and ω 2 respectively, and interferogram is as follows:
S(x
1+ω
1，x
2)-S(x
1，x
2)＝n
1λ (1)
S(x
1+ω
2，x
2)-S(x
1，x
2)＝n
2λ (2)
Wherein n1 and n2 represent the interference fringe level, wherein at n=0,1,2,3, or the like the time constructive interference takes place, at n=0.5, destructive interference takes place in the time of 1.5,2.5 or the like.Two differences of measuring interferogram can be expressed as
S(x
1+ω
1，x
2)-S(x
1+ω
2，x
2)＝(n
1-n
2)λ (3)
Equation (3) can be write as again
S(x
1+(ω
1-ω
2)，x
2)-S(x
1，x
2)＝(n
1-n
2)λ (4)
Equation (4) show two data sets in conjunction with producing a data set or new interferogram, two shear distance that its effective shear distance that has is the individual data collection poor.Utilize this feature, select effective shear distance to equal the spot size of detector, spatial frequency response that just can optimization system.
This method of actual enforcement can be utilized: 1) interferometer system, it is designed to have the interferometry path of two different different shear distance, 2) interferometer system, it has the single interference measuring route, can regulate the shear distance of this system, thus the different interferograms that acquisition has different shear distance.The advantage of structure 1 is can obtain two groups of data simultaneously, and the therefore easier repeatably shear distance that keeps uniformly to be fixed in two paths in each path.The advantage of structure 2 is that it has assembly still less, and is therefore compacter and more cheap.
In the CGS interferometer, can regulate shear distance by changing grating interval, detection wavelength or pitch.
Regulating grating in CGS can utilize above-mentioned actuator to obtain at interval.As an example, to dispose pitch (pitch) be 25 microns at one, survey in the system of grating that wavelength is 632.8 nanometers, 1 micron of the every increase of shear distance, and grating will have to increase by 39 microns at interval.For the shear distance that reaches several micron dimensions changes, piezoelectric sensor (PZT) system is suitable, and motor-driven accurate plateform system is more suitable for causing the grating interval variation of tens of or hundreds of micron dimension shear distance variations.Under any situation, some extra tolerance devices (for example, displacement transducer) may be necessary, are uniform with the variation of guaranteeing grating interval (therefore, shear distance).The advantage of this type systematic is, the adjusting of shear distance is continuous, thereby shortcoming is to be difficult to change equably the homogeneous shear distance that grating keeps crossing over the visual field at interval.
Utilizing the detection wavelength to change shear distance can implement like this,, utilizes the laser (for example argon laser) that the different light source of shutter is housed or can regulates with wavelength that is.As an example, dispose in the system that pitch is 25 microns, a fixed grating grating at interval at one, become 514 nanometers from 632.8 nanometers and can cause 35.64 microns shear distance to change surveying wavelength.The advantage of such system is can obtain uniform shear distance to change, shortcoming is only may be that the shear distance that disperses changes (based on available source wavelength), and the optical system of interferometer can be designed to that two wavelength are had identical response (by design or adjusting).
If change shear distance among the CGS with pitch, two independently in the interferometry path with two pairs of projection gratings, it is at glass or similarly have fixing spectral line pattern on the substrate.Two pairs of gratings have two groups of different gratings, and each has different pitch.Perhaps, can produce the spectral line pattern of grating by electronics or optical means in adjustable mode.For example, the acoustics grating can be used for producing adjustable pitch to change shear distance.
For given application, the structure of shear interference instrument system depends on the power spectrum density of tested component (amplitude is to spatial frequency).Particularly, can select slope sensitivity λ/2 ω, guaranteeing coming the sign amplitude, and can select shear distance to guarantee to characterize spatial frequency (following Nyquist (Nyquist) sampling law) with acceptable signal-to-interference ratio.Like this, for given specimen types, this system can optimised pin.Optimizing actual embodiment is exactly, and can come characterization sample with minimum data, thereby is convenient to efficient calculation and analysis, also is convenient to data storage.
In the selection of slope sensitivity and shear distance, there are some physical constraints.For slope sensitivity, physical constraints is exactly the intensity level resolution of imaging system and surveys wavelength.As the example that the first order is estimated, the ccd array with 10 bit resolutions (1024 gray level) can be differentiated 1/2048 (from representing 1 striped to black Strength Changes in vain) of a striped in theory.If surveying wavelength is 632.8 nanometers, discernmible minimum constructive height difference is 0.31 nanometer (referring to an equation 1) on shear distance.In practice, the whole dynamic ranges that obtain imaging sensor are impossible or unpractical, interference source meeting restricting signal, and this signal can be extracted reliably.Make the dynamic range maximization of imaging sensor and/or the detection wavelength is minimized, can be used for characterizing less amplitude.
The selection of shear distance (so spatial frequency response) may be subjected to some restriction and compromise.The first, space wavelength can not be less than about 2 times of detection wavelength in the plane.The second, at the image array/sensor of fixed measure, the visual field is along with the spot/pixel size linearity reduces.The 3rd, selected shear distance has defined a zone along the sample limit, and the interference data outside the limit can not be collected into.Therefore, single shear distance is big more, and the data aggregation at place, sample limit just is limited more.
The optical shearing interferometer measuring system of above-mentioned CGS and other can be used for measuring directly or indirectly slope and the curvature that is formed on various features and assembly on the substrate.In directly measuring, detecting light beam is directly delivered to the top surface of these device patternings, to obtain curvature information.Surface characteristics on the top surface that will accurately measure and assembly and the zone around them can be flat and be optical reflection.For example, some perfect integrated circuit has the passivation top layer of being made by nonconducting dielectric substance usually, the circuit on the circuit component of these passivation layers on substrate below comprising.The surface of passivation layer is normally flat, and its reflection is enough for this direct measurement.
In some cases, the direct measurement of above-mentioned reflection based on patterned surface may be difficult to implement.For example, feature or the assembly that is formed at substrate front side or their peripheral regions may not be optical reflection.In addition, if the zone around feature and assembly and their, the character except slope or curvature can the distortion of appreciable impact wave front, validity and degree of accuracy based on this direct measurement of patterned top surface reflection will be influenced unfriendly so, because wave front distortion in this case no longer can be represented the global slopes and the curvature of detecting light beam irradiation area.The feature of front side and assembly make the wave front distortion of reflection, may be because of the factor except global slopes and curvature, and for example the height of feature or assembly is different from its zone on every side.Under the situation of these and other, the curvature of curvature or assembly can be measured indirectly, is promptly gone up the curvature measurement release of corresponding position by substrate rear side apparent surface.This is possible, because the stress in discrete feature on substrate or the assembly can make substrate deform, and the film that is formed on the substrate conforms to the overall curvature of substrate surface usually.
Height around some feature and their not simultaneously, at each feature, the distortion mutually on the reflected probe beam wave front comprises at least by the part of difference in height influence with by the part of curvature influence.Because the rear surface is not patterned, any optical interdferometer (comprising non-shearing interferometer) can be used for handling the reflection from the rear surface, to obtain surface curvature information.For example, the Twyman-Green of non-shearing and Michaelson interferometer can be used for obtaining the optical measurement value of the non-patterning of wafer rear surface.
It should be noted, can come the front surface or the top surface of optical measurement wafer patternization, and can come (comprise and shearing or non-shearing interferometer) rear surface of the non-patterning of optical measurement with any interferometer with above-mentioned phase shift shearing interferometer.Two measurements can be processed or contact measure with the integral body of improving patterned front surface.Surface information from non-patterning rear surface can be used to provide the whole integral surface slope information of wafer.And can advantageously obtain, and can be used to provide the detailed local surface information of patterned front surface from shearing interferometer from the surface information of patterning front side surface.
In one embodiment, the rear surface of wafer is supported by chip support, in part because the front surface of patterning for example circuit and other microstructure can be damaged by the contact of this class support component.Figure 12 shows exemplary planning chart, and it is used for measuring with optical mode the rear surface of wafer.The chip support that contacts with the rear surface influences optical measurement because appearing at irradiation area, therefore part has hindered from folded light beam and obtained the surface information that chip support occupies local.These effects of support do not wish to take place, and should be eliminated.
Figure 13 shows an example, and wherein the rear side of wafer is that die support by three asymmetric manners location supports, and makes that repeatedly measuring wafer with different angle orientation just can directly collect data on whole wafer surface.Figure 13 does not illustrate with one in the positioned at arbitrary angles wafer is placed into hardware (placing and rotating device, as commonly used in the automatic industrial) on the thin support.The measurement that Figure 13 further illustrates the wafer rear side can produce discontinuous interference pattern, this discontinuous be because the point that exists in measurement field supports.In traditional the setting, these interference can hinder and convert interference pattern to contain information data.Technology more described herein can allow to measure the zone that is occupied by chip support.
In one embodiment, come effectively the interference pattern on the discontinuous interference fringe to be carried out interpolation with interpolation algorithm, this discontinuous be that existence by chip support causes.The interpolation stripe edge can be extrapolated interference fringe, and this interference fringe can be used in the standard interference measurement Processing Algorithm.The algorithm that is used for producing these inferred fringes can be linear interpolation algorithm, spline interpolation algorithm, higher order polynomial interpolation algorithm and some algorithms that utilizes spatial filtering and one or more above-mentioned technology.Just can release the spatial filtering coefficient by experimental data and the gross data of analyzing wafer distortion, wafer distortion is caused by semiconductor and MEMs processing technology.
In case finished interpolation, based on spatial frequency content and with wafer on the consistance of other interference fringe, the software that drives described device also carries out " sense check " (sense check) to interference fringe resulting, that extrapolate.
Under many circumstances, these algorithms can be enough to interferometric striped data, make it convert implication abundant wafer shape, slope, curvature and stress information to.Yet if require the Measurement Resolution of higher level, device just should be measured the rear side of wafer with a plurality of angle orientation.Then, the consistance of the more a plurality of images of device, and missing data is by another image (promptly to make an image (that is the wafer part that is covered by support), with the image that different location obtains, what supported pin occupied in the wherein previous image no longer is covered to certain portions) data fill.The algorithm of carrying out this calculating is conspicuous.
Device also can utilize the supporting pin of transparent lens properties, and these supporting pins are sightless substantially for the probing wave front.These sway braces and supporting pin are processed by the machinability quartz, and polish through the grinding technics of complexity.
Some embodiment have only been described.But, it should be understood that and can make amendment and improve.
Claims (62)
1. method, it comprises:
The detecting light beam that utilization has basic homogeneous wave front shines a surface to be measured, to produce the reflected probe beam that has distortion in that caused by described lip-deep irradiation area, the reflected wavefront;
Guide described reflected probe beam by an optical shearing interferometer instrument, an optical interference pattern between duplicating with another that obtains described reflected wavefront and described reflected wavefront, another copy space of wherein said reflected wavefront the shear distance that has been shifted;
Regulate described another phase shift between duplicating of described reflected wavefront and described reflected wavefront, from described optical shearing interferometer instrument, to obtain a plurality of phase-shifted interference pattern of different phase shifts; And
Handle described interference pattern, to obtain the surface slope information on the irradiation area described in the described surface to be measured.
2. method according to claim 1 further comprises coherent gradient sensing (CGS) system with diffraction grating as described optical shearing interferometer instrument.
3. method according to claim 1 further comprises a radial-shear interferometer as described optical shearing interferometer instrument.
4. method according to claim 1 further comprises a bilateral scissors shearing interferometer with clapboard as described optical shearing interferometer instrument.
5. method according to claim 1 further is included in the described optical shearing interferometer instrument with prism and produces described optical interference pattern between described the duplicating of described reflected wavefront and described reflected wavefront.
6. method according to claim 1 further comprises and regulates described phase shift, to produce the phase shift of 0,90,180,270 and 360 degree.
7. method according to claim 1 further is included in the processing of described interference pattern of different phase shifts, and uses algorithm to be calculating phase information, thereby extracts the surface slope information of the above irradiation area of described surface to be measured.
8. method according to claim 7 further is included in and uses minimum discontinuous (MDF) algorithm in the algorithm.
9. method according to claim 7 further is included in and uses pre-service conjugate gradient (PCG) algorithm in the algorithm.
10. method according to claim 7 further is included in and uses the branch cut min algorithm in the algorithm.
11. method according to claim 7 further is included in and uses a watt formula modulation bootstrap algorithm in the algorithm.
12. method according to claim 7 further comprises with statistical and comes match measured surface slope with a surperficial polynomial expression.
13. method according to claim 12 further comprises with Jone Ke's polynomial expression as surperficial polynomial expression.
14. method according to claim 12 further comprises integration and additive process are applied in the statistics surface fitting of described measured surface slope.
15. method according to claim 1 further comprises the curvature information of utilizing described surface slope to obtain described irradiation area.
16. method according to claim 1 further comprises the stress information that utilizes described surface slope to obtain described irradiation area.
17. method according to claim 1 further is included in the processing of described interference pattern and uses phase extraction algorithms.
18. comprising, method according to claim 17, wherein said phase extraction algorithms be selected from a kind of in Bucket A, Bucket B, the Bucket C algorithm.
19. method according to claim 12 further comprises surperficial polynomial expression is made in the Legendre polynomial effect.
20. a system, it comprises:
A collimated telescope source, it produces a collimated probe beam to surface to be measured;
An optical shearing interferometer instrument apparatus, it is placed with the described detecting light beam that can receive from described surface reflection, and another optical interference between duplicating that can cause the reflected wavefront of described detecting light beam and described reflected wavefront, described another copy space of described reflected wavefront shear distance that has been shifted, wherein can make described optical shearing interferometer instrument regulate phase shift between described the duplicating of described reflected wavefront and described reflected wavefront, to obtain to have a plurality of phase-shifted interference pattern of different phase shifts;
An imaging device, it takes the described interference pattern that is produced by described optical shearing interferometer instrument; With
A treating apparatus, it handles the interference pattern of being taken by described imaging device, to obtain the surface slope information on irradiation area described in the described surface to be measured.
21. system according to claim 20, wherein said optical shearing interferometer instrument comprises coherent gradient sensing (CGS) system with diffraction grating.
22. system according to claim 20, wherein said optical shearing interferometer instrument comprises a radial-shear interferometer.
23. system according to claim 20, wherein said optical shearing interferometer instrument comprises a bilateral scissors shearing interferometer with clapboard.
24. system according to claim 20, wherein said optical shearing interferometer instrument comprises prism, and its work is to produce described reflected wavefront and the described reflected wavefront described optical interference pattern between duplicating.
25. system according to claim 20, wherein said optical shearing interferometer instrument is regulated described phase shift, to produce the phase shift of 0,90,180,270 and 360 degree.
26. system according to claim 20, wherein said treating apparatus is programmed, with the phase information in the described interference pattern of untiing different phase shifts, to extract the surface slope in the above irradiation area of described surface to be measured.
27. system according to claim 26 wherein uses the described treating apparatus of minimum discontinuous (MDF) algorithm to be programmed, to untie described phase information.
28. system according to claim 26 wherein uses pre-service conjugate gradient (PCG) algorithm that treating apparatus is programmed, to untie described phase information.
29. system according to claim 26 wherein is programmed with the described treating apparatus of branch cut min algorithm, to untie described phase information.
30. system according to claim 26 wherein is programmed with watt described treating apparatus of formula modulation bootstrap algorithm, to untie described phase information.
31. described treating apparatus is wherein operated by system according to claim 26, comes match measured surface slope with statistical with a surperficial polynomial expression.
32. system according to claim 31, wherein said treating apparatus is programmed, and carries out statistical fit with utilization Jone Ke's polynomial expression.
33. described treating apparatus is wherein operated by system according to claim 31, thereby integration and additive process are applied in the statistics surface fitting of described measured surface slope.
34. described treating apparatus is wherein operated by system according to claim 20, thereby obtains the curvature information of described irradiation area with described surface slope.
35. described treating apparatus is wherein operated by system according to claim 20, thereby obtains the stress information of described irradiation area with described surface slope.
36. system according to claim 31, wherein said treating apparatus is programmed, and carries out statistical fit with the utilization Legendre polynomial.
37. system according to claim 20, wherein said treating apparatus is programmed, to use phase extraction algorithms in the processing of described interference pattern.
38. according to the described system of claim 37, wherein said phase extraction algorithms comprises and is selected from a kind of in Bucket A, Bucket B, the Bucket C algorithm.
39. a method, it comprises:
With the rear surface of support component contact wafer,, wherein on the described wafer front surface opposite, be shaped on pattern with described rear surface to support described wafer;
Shine described rear surface with detecting light beam, to produce the reflected probe beam that has distortion in that cause by the irradiation area on the described rear surface, the reflected wavefront;
Produce an optical interference pattern with described reflected probe beam, wherein said interference pattern comprises the interruption that exists support component to cause owing on described rear surface;
In the processing of described optical interference pattern, use interpolation algorithm, so that interpolation is carried out having the interference fringe that causes on the zone of described interruption in described rear surface, thus interference pattern feature that obtain only to cause, in the described irradiation area by described rear surface; And
Described interpolated interference pattern from described rear surface is handled, with the surface slope of relevant position on the described front surface that obtains described wafer.
40., further comprise with linear interpolation algorithm described interference fringe carried out interpolation according to the described method of claim 39.
41., further comprise with the spline interpolation algorithm coming described interference fringe is carried out interpolation according to the described method of claim 39.
42., further comprise according to the consistance of other striped in spatial frequency content and the described interference pattern and come verification interpolation striped according to the described method of claim 39.
43., further comprise according to the described method of claim 39:
Utilize angle orientation that described support component changes described wafer at least once, thereby obtain at least one another reflected probe beam and another optical interference pattern;
In the processing of described another optical interference pattern, use described interpolation algorithm, so that interpolation is carried out having the interference fringe that causes on the zone of described interruption in described rear surface, thus interference pattern feature that obtain only to cause, in the described irradiation area by described rear surface;
Processing is from described another interference pattern of described rear surface, with the surface slope of relevant position on the described front surface that obtains described wafer;
Interference information between the interference pattern of different angles location acquisition is compared, to find missing data; And
Fill the missing data of a position of interference pattern, this is to realize by the data of utilizing position described in another interference pattern that obtains at place, different angles location.
44., further comprise with asymmetric manner the described rear surface that described support component supports described wafer is set according to the described method of claim 39.
45. according to the described method of claim 39, further comprise with shearing interferometer and handle described reflected probe beam, to produce described optical interference pattern.
46. according to the described method of claim 39, further comprise with non-shearing interferometer and handle described reflected probe beam, to produce described optical interference pattern.
47., further comprise according to the described method of claim 46:
Second detecting light beam is directed to described patterned front surface, produces second reflected probe beam with optical reflection by described patterned front surface;
Utilize shearing interferometer to handle described second reflected probe beam, to produce second optical interference pattern; And
From described optical interference pattern and described second optical interference pattern, extract the surface information of described patterned front surface.
48. a method, it comprises:
With the rear surface of support component contact wafer,, wherein on the described wafer front surface opposite, be shaped on pattern with described rear surface to support described wafer;
Shine described rear surface with detecting light beam, to produce the reflected probe beam that has distortion in that cause by the irradiation area on the described rear surface, the reflected wavefront;
Produce an optical interference pattern with described reflected probe beam, wherein said interference pattern comprises the interruption that exists support component to cause owing on described rear surface;
Described interference pattern from described rear surface is handled, with the surface slope of relevant position on the described front surface that obtains described wafer;
At least once change the angle orientation of described the above wafer of support component, thereby obtain at least one another reflected probe beam, thereby obtain another optical interference pattern from identical detecting light beam;
Described another interference pattern from described rear surface is handled, with the surface slope of relevant position on the described front surface that obtains described wafer;
The surface slope that obtains from the different interference patterns of described wafer different angles location is compared; And
Be filled in the missing data that the place, a position in the interference pattern is found, this is to realize by the data of utilizing position described in another interference pattern that obtains at place, different angles location.
49. according to the described method of claim 48, further comprise with asymmetric manner described support component is set, to support the described rear surface of described wafer.
50. a method, it comprises:
With the rear surface of support component contact wafer, supporting described wafer, wherein said support component is by making the light material transparent of surveying wavelength, and is shaped on pattern on the described wafer front surface opposite with described rear surface;
Detecting light beam with described detection wavelength shines described rear surface, to produce the reflected probe beam that has distortion in that caused by the irradiation area on the described rear surface, the reflected wavefront;
Produce an optical interference pattern with described reflected probe beam; And
Described interference pattern from described rear surface is handled, with the surface slope of relevant position on the described front surface that obtains described wafer.
51. a method comprises:
Shine surface to be measured with detecting light beam, thereby produce that cause by this surface, as to have a distorted wavefront new light beam with basic homogeneous wave front;
Guide described new light beam by the optical shearing interferometer instrument apparatus, optical interference pattern between duplicating with another that obtains described distorted wavefront and described distorted wavefront, described another copy space of wherein said distorted wavefront the shear distance that has been shifted;
Regulate described shear distance to obtain the optical interference pattern of different shear distance; And
Described interference pattern to different shear distance is handled, to extract described lip-deep information to be measured.
52., comprise that further the optical reflection that utilizes described surface produces described new light beam according to the described method of claim 51.
53., comprise that further the optical transmission that utilizes described surface produces described new light beam according to the described method of claim 51.
54., further comprise a coherent gradient sensor-based system (CGS) interferometer as described optical interdferometer according to the described method of claim 51.
55., further comprise according to the described method of claim 51:
Two interference patterns that will have two different shear distance subtract each other, thereby produce a differential interference pattern, the corresponding new shear distance of this differential interference pattern, and this new shear distance equals the poor of described two different shear distance.
56., further comprise the beam sizes of described new shear distance being elected as described detecting light beam according to the described method of claim 55.
57. a method, it comprises:
On the wafer surface of a wafer, carry out chemically mechanical polishing;
During described chemically mechanical polishing, shine described wafer surface with a detecting light beam, thereby produce that cause by described wafer surface, as to have a distorted wavefront new light beam with basic homogeneous wave front;
Guide new light beam by an optical shearing interferometer instrument, the optical interference pattern between duplicating with another that obtains described distorted wavefront and described distorted wavefront, described another copy space of wherein said distorted wavefront the shear distance that has been shifted;
Regulate described shear distance to obtain the optical interference pattern of different shear distance; With
Described interference pattern to different shear distance is handled, to extract the surface microscopic topology information on the described wafer surface; And
The information that utilization is extracted is controlled the operating parameter in the described chemically mechanical polishing.
58., further comprise the slurry flow velocity that changes described chemically mechanical polishing according to the information of being extracted according to the described method of claim 57.
59., further comprise the polishing pad pressure that changes described chemically mechanical polishing according to the information of being extracted according to the described method of claim 57.
60., further comprise the polishing pad speed that changes described chemically mechanical polishing according to the information of being extracted according to the described method of claim 57.
61., further comprise the slurry composition that changes described chemically mechanical polishing according to the information of being extracted according to the described method of claim 57.
62., further comprise according to the information of being extracted changing polishing pad hardness according to the described method of claim 57.
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| US44332903P | 2003-01-28 | 2003-01-28 | |
| US60/443,342 | 2003-01-28 | ||
| US60/443,329 | 2003-01-28 | ||
| US60/443,804 | 2003-01-29 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102037546B (en) * | 2008-02-29 | 2014-01-29 | 康宁股份有限公司 | Methods of making an unsupported article of pure or doped semiconducting material |
| CN103925886A (en) * | 2013-01-15 | 2014-07-16 | 中芯国际集成电路制造(上海)有限公司 | Wafer deformation detection system and method |
| CN110296666A (en) * | 2018-03-23 | 2019-10-01 | 泓邦科技有限公司 | Three-dimensional measuring device |
| CN110940298A (en) * | 2019-12-17 | 2020-03-31 | 重庆理工大学 | Autocollimator |
| CN111527372A (en) * | 2017-10-10 | 2020-08-11 | 斯特凡Tto有限公司 | Detection of fields |
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2004
- 2004-01-28 CN CN 200480006296 patent/CN1759296A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102037546B (en) * | 2008-02-29 | 2014-01-29 | 康宁股份有限公司 | Methods of making an unsupported article of pure or doped semiconducting material |
| CN103925886A (en) * | 2013-01-15 | 2014-07-16 | 中芯国际集成电路制造(上海)有限公司 | Wafer deformation detection system and method |
| CN111527372A (en) * | 2017-10-10 | 2020-08-11 | 斯特凡Tto有限公司 | Detection of fields |
| US11353523B2 (en) | 2017-10-10 | 2022-06-07 | Sintef Tto As | Detection of fields |
| CN110296666A (en) * | 2018-03-23 | 2019-10-01 | 泓邦科技有限公司 | Three-dimensional measuring device |
| CN110296666B (en) * | 2018-03-23 | 2021-04-20 | 泓邦科技有限公司 | Three-dimensional measuring device |
| CN110940298A (en) * | 2019-12-17 | 2020-03-31 | 重庆理工大学 | Autocollimator |
| CN110940298B (en) * | 2019-12-17 | 2021-07-27 | 重庆理工大学 | Autocollimator |
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