CN101510051A - Inspection method and equipment, photolithography equipment and method for manufacturing photolithography processing unit and device - Google Patents

Abstract

A scatterometer is provided with a radiation source which can be emitted and radiated within different first and second wavelength scopes. An adjustable optical element setting is used for realizing the color aberration amendment according to the need of used wavelength scope. A single-scattering instrument can thus adopt a wavelength with wide intervals for realizing measurement.

Description

The method of inspection and equipment, lithographic equipment, lithographic processing cell and device making method

Technical field

The present invention relates to a kind of for example can be used for is making the method for checking in the device by photoetching technique, and relates to a kind of method, especially scatterometer method that adopts photoetching technique to make device.

Background technology

Lithographic equipment is a kind of machine that (is applied to usually on the target part of described substrate) on the substrate that required pattern is applied to.For example, lithographic equipment can be used in the manufacturing of integrated circuit (IC).In this case, the pattern that is called mask or mask (reticle) alternatively can be formed device and be used to be created on circuit pattern to be formed on the individual layer of described IC.This design transfer can be arrived on the target part (part that for example, comprises a part of tube core, one or more tube cores) on the substrate (for example, silicon wafer).Typically, via imaging with described design transfer on the radiation-sensitive materials that is provided with on the described substrate (resist) layer.Usually, single substrate will comprise the network of the adjacent target part of continuous formation pattern.Known lithographic equipment comprises: so-called stepper, in described stepper, by exposing an entire pattern onto described target each the target part of radiation of partly coming up; And so-called scanner, in described scanner, by radiation beam along assigned direction (" scanning " direction) scan described pattern, simultaneously scan described substrate with this direction comes each target part of radiation parallel or antiparallelly.Can also described pattern be formed device from described pattern transfer on the described substrate by described pattern is impressed (imprinting) to described substrate.

For monitoring photoetching technology, usually measure one or more parameters of the substrate that is patterned, for example, in substrate or the aliasing error between the successive layers that forms on the substrate.Have the various technology that the micromechanism that photoetching process forms is measured of being used for, described technology comprises uses scanning electron microscope and various professional tool.A kind of professional inspection instrument of form is a scatterometer, and in described scatterometer, radiation beam is directed on the lip-deep target of substrate, and one or more attributes of the bundle of process scattering or reflection are measured.By for described bundle reflected by substrate or scattering before and afterwards one or more attributes compare, can determine one or more attributes of described substrate.This can be for example finishes by reflecting bundle and data in being stored in the known measured value storehouse that is associated with known substrate attribute are compared.The scatterometer of two kinds of main types is known.The spectral dispersion instrument is directed to the broadband radiation bundle on the substrate, and measures the radiation spectrum be dispersed into specific narrow angular range (as the intensity of the function of wavelength).Angle decomposition scatter is measured the intensity of the radiation that is scattered as the function of angle.Ellipsometer is measured polarization state.Angle decomposition scatter and ellipsometer can adopt homogeneous beam, multicolour light beam (light beam that promptly has the composition of a plurality of different wavelength) or broad band light beam.

It is achromatic adopting broadband or multicolour light beam need make the optical system of scatterometer.It is known being used to make the achromatic technology of the optical system that relates to refraction optical element, but along with the increase of the quantity or the scope of wavelength to be adapted to, it is more complicated and difficult that described technology becomes.Can more easily make employing is achromatic based on the optical system of the catoptron of Schwartz Xi Er (Schwarzschild) optical element for example, but because blocking on the pupil plane, described optical system is inapplicable, especially for the scatterometer and the ellipsometer of the optical system with high-NA.

Summary of the invention

Be intended to for example provide a kind of wavelength of wide interval or method and apparatus of the scatterometer that wavelength coverage is measured of can adopting more.

According to an aspect of the present invention, provide a kind of inspection machine, described inspection machine configuration is used for determining and by being used for being printed in the photoetching process of making device layer on the substrate value of the parameter correlation of the target pattern on the substrate, described equipment comprises:

Radiation source is provided for launching selectively first radiation beam with first wavelength in first wavelength coverage, perhaps has second radiation beam of second wavelength in second wavelength coverage, and described second wavelength coverage is different from described first wavelength coverage;

Optical system, one that is provided for being selected in first or second radiation beam is directed on the target pattern, and will by the tomographic projection of target pattern break-in to the detecting device to obtain the spectrum (scatterometric spectra) of scatterometer spectrum or scatterometry; And

Adjustable optical element, being provided for launching first radiation beam according to radiation source selectively still is second radiation beam, realizes the aberration correction of optical system.

According to an aspect of the present invention, provide a kind of be used for determining with by being used for being printed on the method for inspection of value of the parameter correlation of the target pattern on the substrate in the photoetching process of making device layer on the substrate, described method comprises:

The control radiation source is launched first radiation beam with first wavelength in first wavelength coverage selectively, perhaps has second radiation beam of second wavelength in second wavelength coverage, and described second wavelength coverage is different from described first wavelength coverage;

Adopt optical system that of selecting in first radiation beam or second radiation beam is directed on the target pattern, and will be by the tomographic projection of target pattern break-in to detecting device, to obtain the spectrum of scatterometer spectrum or scatterometry; And

Adjusting adjustable optical element still is the aberration correction that second radiation beam is realized optical system selectively to launch first radiation beam according to radiation source.

According to an aspect of the present invention, provide a kind of inspection machine, described inspection machine configuration is used for determining and by being used for being printed in the photoetching process of making device layer on the substrate value of the parameter correlation of the target pattern on the substrate, described equipment comprises:

Optical system, be provided for to have first radiation beam of first wavelength in first wavelength coverage, second radiation beam that perhaps has second wavelength in second wavelength coverage is directed on the target pattern, and will by the tomographic projection of target pattern break-in to the detecting device to obtain the spectrum of scatterometer spectrum or scatterometry, described second wavelength coverage is different from described first wavelength coverage, described optical system comprises object lens and imaging optical system, described object lens have pupil plane and are provided for revising by the radiation of target pattern break-in, and described imaging optical system is provided for image projection with pupil plane to detecting device; And

Adjustable optical element is provided for selectively realizing the aberration correction of described optical system according to being that first radiation beam or second radiation beam are guided by optical system.

Description of drawings

, embodiments of the invention are described with reference to accompanying schematic figure only by example at this, in accompanying schematic figure, identical Reference numeral is represented identical part, and wherein:

Fig. 1 a illustrates lithographic equipment;

Fig. 1 b illustrate lithographic cell or bunch;

Fig. 2 illustrates first scatterometer according to an embodiment of the invention;

Fig. 3 illustrates second scatterometer according to an embodiment of the invention;

Fig. 4 illustrates the 3rd scatterometer according to an embodiment of the invention; And

Fig. 5 illustrates the 4th scatterometer according to an embodiment of the invention.

Embodiment

The schematically illustrated lithographic equipment according to an embodiment of the invention of Fig. 1.Described equipment comprises:

Irradiation system (irradiator) IL, configuration is used to regulate radiation beam B (for example, UV radiation or deep ultraviolet (DUV) radiation);

Supporting construction (for example mask platform) MT, configuration is used to support pattern and forms device (for example mask) MA and be used for accurately locating the first steady arm PM that pattern forms device according to the parameter of determining with configuration and link to each other;

Substrate table (for example wafer station) WT, configuration is used to keep substrate (for example being coated with the wafer of resist) W, and with configuration be used for according to the parameter of determining accurately the second steady arm PW of position substrate link to each other; And

Optical projection system (for example refraction type projection lens system) PS, described optical projection system PS configuration is used for giving the target portion C of the graphic pattern projection of radiation beam B to substrate W (for example comprising or many tube cores) with formed device MA by pattern.

Described irradiation system can comprise various types of opticses, the combination in any of the optics of refractive, reflection-type, magnetic type, electromagnetic type, electrostatic or other types or above-mentioned optics for example is with to radiation channeling conduct, shaping or control.

Supporting construction is with the design of the orientation that depends on pattern and form device, lithographic equipment and form the mode whether device remain on medium other conditions of vacuum environment such as for example pattern and keep pattern to form device.Described supporting construction can adopt machinery, vacuum, static or other clamping technology keep pattern to form device.Described supporting construction can be framework or platform, for example, framework or platform can be as required for fixing or movably.Described supporting construction can guarantee that pattern forms device (for example with respect to optical projection system) and is positioned on the desired position.Any use of term " mask " or " mask " here can be thought and more upper term " pattern formation device " synonym.

Here employed term " pattern formation device " should be interpreted as to represent can be used in to give radiation beam so that partly form any device of pattern in the target of substrate on the xsect of radiation beam with pattern widely.Should be noted that the pattern that is endowed radiation beam can with at the required pattern of substrate target part definitely not conform to (if for example this pattern comprises phase shift feature or so-called supplemental characteristic).Usually, the pattern that is endowed radiation beam will conform to the specific functional layer in the device that target partly forms such as integrated circuit.

It can be transmission-type or reflective that pattern forms device.The example that pattern forms device comprises mask, array of programmable mirrors and liquid crystal display able to programme (LCD) panel.Mask is known in photoetching, and comprises the mask-type such as binary mask type, alternating phase-shift mask type, attenuated phase-shifting mask type and various hybrid mask types.The example of array of programmable mirrors adopts the matrix arrangements of small reflector, and each small reflector that can tilt independently is so that reflect the radiation beam of incident along different directions.The described catoptron that tilts gives pattern by described catoptron matrix radiation reflected bundle.

Term used herein " optical projection system " should be interpreted as comprising widely the optical projection system that is suitable for any types employed exposing radiation or other factors such as using immersion liquid or use vacuum, comprise the combination in any of refractive, reflection-type, reflection-refraction type, magnetic type, electromagnetic type and electrostatic optical systems or said system.Here any use of term " projecting lens " can be thought and more upper term " optical projection system " synonym.

As shown here, described equipment is transmission-type (for example, adopting transmissive mask).Alternatively, described equipment can be reflection-type (for example, adopt the array of programmable mirrors of type as mentioned above, or adopt reflection type mask).

Described lithographic equipment can be the type with two (two platforms) or more substrate tables (and/or two or more supporting construction).In this " many " machine, can use additional platform and/or supporting construction concurrently, or can be with one or more other and/or when supporting construction is used to expose, on one or more and/or supporting construction, carry out preliminary step.

Described lithographic equipment also can be that wherein at least a portion substrate can be had relative high refractive index liquid (for example water) covering so that fill the type in the space between optical projection system and the substrate.Immersion liquid also can be applied in other spaces in the lithographic equipment (for example between described mask and optical projection system).The numerical aperture that immersion technique is used to increase optical projection system is being known in the art.Here employed this term " submergence " does not also mean that structure (for example substrate) must be immersed in the liquid, and only means that in exposure process liquid is between optical projection system and substrate.

With reference to Fig. 1 a, described irradiator IL receives the radiation beam that sends from radiation source S O.This source and described lithographic equipment can be independent entities (for example when this source is excimer laser).In this case, this source can be considered to the ingredient that forms lithographic equipment, and the help of the bundle transmission system BD by comprising suitable guide catoptron for example and/or beam expander, described radiation beam is passed to described irradiator IL from described source SO.In other cases, described source can be the ingredient or the integral part (for example when described source is mercury lamp) of described lithographic equipment.Described source SO and described irradiator IL and described bundle transmission system BD (described if desired bundle transmission system BD) can be called radiating system together.

Described irradiator IL can comprise the adjuster AD of the angle intensity distributions that is used to adjust described radiation beam.Usually, can adjust outside at least and/or inner radially (radial) scope (generally being called σ-outside and σ-inside) of the intensity distributions in the pupil plane of described irradiator.In addition, described irradiator IL can comprise various miscellaneous parts, for example integrator IN and condenser CO.Described irradiator can be used to regulate described radiation beam, in its xsect, to have required homogeneity and intensity distributions.

Described radiation beam B incides the described pattern that remains on supporting construction (for example, mask platform) MT and forms on device (for example, the mask) MA, and forms pattern by described pattern formation device.Passed pattern and formed after the device MA, described radiation beam B is by optical projection system PS, and described optical projection system PS focuses on radiation beam on the target portion C of described substrate W.By the second steady arm PW and position transducer IF (for example, interferometry device, linear encoder or capacitive transducer) help, can accurately move described substrate table WT, for example so that the different target portion C is positioned in the radiation path of described radiation beam B.Similarly, for example the machinery from the mask storehouse obtain or machine searching after, or in scan period, the described first steady arm PM and another position transducer (clearly not illustrating among Fig. 1 a) can be used for that pattern is formed device MA and accurately locate with respect to the radiation path of described radiation beam B.The long-range module (coarse positioning) of a part that usually, can be by forming the described first steady arm PM and the help of short distance module (fine positioning) realize that supporting construction MT's is mobile.Similarly, can adopt the long-range module of a part that forms the described second steady arm PW and short distance module to realize moving of described substrate table WT.Under the situation of stepper (opposite with scanner), described supporting construction MT can only link to each other with the short distance actuator, maybe can fix.Can use pattern formation device alignment mark M1, M2 and substrate alignment marks P1, P2 to come alignment pattern to form device MA and substrate W.Although shown substrate alignment marks has occupied the application-specific target part, they can be in the space between the target part (these are known as the line alignment mark).Similarly, under the situation that will be arranged on more than one tube core on the pattern formation device MA, described pattern forms the device alignment mark can be between described tube core.

Described equipment can be used at least a of following pattern:

1. in step mode, when the whole pattern that will give described radiation beam once projects on the target portion C, supporting construction MT and described substrate table WT are remained static substantially (that is, single static exposure).Then described substrate table WT is moved along X and/or Y direction, make and to expose to the different target portion C.In step mode, the full-size of exposure field has limited the size of the described target portion C of imaging in single static exposure.

2. in scan pattern, when the graphic pattern projection that will give described radiation beam is on the target portion C, supporting construction MT and substrate table WT are synchronously scanned (that is, single dynamic exposure).Substrate table WT can determine by (dwindling) magnification and the image inversion feature of described optical projection system PS with respect to speed and the direction of supporting construction MT.In scan pattern, the full-size of exposure field has limited the width (along the width of non-direction of scanning) of the described target part in the single dynamic exposure, and the length of described scanning motion has been determined the height (along the height of described direction of scanning) of described target part.

3. in another pattern, the supporting construction MT that keeps pattern able to programme to form device is remained basic stationary state, and when the graphic pattern projection that will give described radiation beam is on the target portion C, described substrate table WT is moved or scans.In this pattern, adopt impulse radiation source usually, and after the moving each time of described substrate table WT or between the continuous radiation pulse in scan period, upgrade described pattern able to programme as required and form device.This operator scheme can be easy to be applied to utilize pattern able to programme to form in the maskless lithography of device (for example, the array of programmable mirrors of type) as mentioned above.

Also can adopt the combination and/or the variant of above-mentioned use pattern, or diverse use pattern.

Shown in Fig. 1 b, lithographic equipment LA forms the part of lithographic cell LC (be also referred to as sometimes photoetching bunch), and described lithographic cell also comprises and is used for realizing on substrate before one or more exposures and the device of the technology after the exposure.Usually, these comprise one or more spinner SC of being used for the deposit resist layer, are used for one or more developer DE that the resist that exposed is developed, one or more chill plate CH and one or more bake plate BK.Lining processor or mechanical arm RO pick up substrate from I/O port I/O1, I/O2, it is moved between different process units, and it is passed to the loading bay LB of lithographic equipment.These devices that often are referred to as track (track) are under the control of track control module TCU, described track control module TCU self is by management control system SCS control, and described management control system SCS is also via photoetching control module LACU control lithographic equipment.Therefore, different equipment can be operated and be used for turnout and treatment effeciency maximization.

For the substrate by lithographic equipment exposure correctly and is as one man exposed, need check through the substrate of overexposure to measure one or more attributes, for example aliasing error between two successive layerss, line thickness, critical dimension (CD) etc.If the error of detecting can be adjusted (if especially check can be finished or enough rapid still being in to another substrate that makes same batch treated exposure status at once) to the exposure of one or more continuous substrates.The substrate that had exposed also can be stripped from and rework (so that improve output), or abandoned, avoids thus exposing on the known substrate that has a defective.Partly exist under the situation of defective in some targets of substrate only, can only partly further expose those intact targets.Another kind may be to set continuous processing step, and with the needs of adaptive compensation error, the time of for example repairing etch step can be adjusted and be used to compensate the variation to the critical dimension of substrate of the substrate that caused by lithographic process steps.

Inspection machine is used to determine one or more attributes of substrate, and especially, be used for determining different substrates or same substrate different layers one or more attributes how from the layer to the layer and/or from one side of substrate to the variation of another side.Inspection machine can be integrated among lithographic equipment LA or the lithographic cell LC, maybe can be independent device.In order the most promptly to measure, need inspection machine upright measurement the after the exposure at one or more attributes on the resist layer of overexposure.Yet, latent image in the resist have very low contrast (through the resist of radiant exposure part and between the resist part through radiant exposure very little refringence is not only arranged), and be not that all inspection machines all have enough sensitivity and come latent image is effectively measured.Therefore, measurement can be carried out behind the baking procedure after the exposure (PEB), baking procedure after the described exposure (PEB) is normally at the first step that carries out on the substrate of overexposure, and increased resist through overexposure with without the contrast between the part of exposure.In this stage, it is half potential that the image in the resist can be called as.Also can be in the exposed portion of resist or non-exposed portion removed moment, perhaps after such as pattern transfer steps such as etchings, to measuring through the resist image that develops.A kind of possibility of processing again that may limit defective substrate in back, but still can provide Useful Information, for example for purpose of process control.

Fig. 2 illustrates scatterometer SM1 according to an embodiment of the invention.It comprises broadband (white light) the tomographic projection device 2 of tomographic projection to the substrate W.Institute's radiation reflected is transferred to spectrometer detector 4, and described spectrometer detector 4 is measured by the spectrum 10 of the radiation of direct reflection (being about to the function measurement of intensity as wavelength).From these data, produce the structure of the spectrum detected or distribute and can rebuild by processing unit PU, for example by rigorous couple-wave analysis (rigorous coupled waveanalysis) and non-linear regression or by with bottom Fig. 2 shown in the simulated spectra storehouse compare.Usually,, know the cardinal principle form of described structure and suppose some parameters, only leave some structural parameters and determine according to scatterometry data (scatterometry data) according to the knowledge of the manufacture craft of described structure for described reconstruction.This scatterometer can be configured to normal incidence scatterometer or oblique incidence scatterometer.

According to embodiments of the invention, radiation source 2 can be controlled and be used for at least two kinds of different wavelength coverages output radiations selectively, for example in ultraviolet range (less than 300nm) and near infrared range (700-800nm).Radiation source 2 can comprise first radiation source that is used to launch UV radiation, for example deuterium lamp or xenon lamp.Therefore, first wavelength coverage that can be exported by described radiation source can be at about 200nm to the scope of about 300nm.Radiation source 2 also can comprise second radiation source, for example quartz-tungsten halogen (quartz-tungsten-halogen) radiation source or laser, and perhaps laser diode is with the emission near-infrared radiation.Second wavelength coverage that can be exported by radiation source can be in the scope from about 700nm to about 800nm.For described first and second radiation sources, one or more wave filters can be set for the wavelength coverage that will be launched and be restricted in the needed scope.In order to export the radiation in first and second wavelength coverages, excite first and second radiation sources selectively.Alternatively, two provenances can be excited simultaneously and shutter separately can open and close, and perhaps move the bundle steering component, to select output from required radiation source.If different wavelength coverage to be used is enough near, then also can adopt single tunable radiation source.In order to make it possible between more than two wavelength coverage, to select, can provide more than two selectable radiation sources and/or tunable radiation source.

Radiation in ultraviolet range is useful for measuring CD; Owing to the improvement of obtainable CD value along with photoetching technique diminishes, need shorter wavelength accurately to measure.Radiation near infrared range is useful for the overlapping measurement in the layer of polysilicon or similar polysilicon.Other wavelength coverage may be particularly useful for other measurement.By provide can be in two or more different scopes radiation emitted source selectively, can in single scatterometer, carry out different measurement (for example CD and overlapping).Owing to can on substrate, carry out multiple measurement, and need be between scatterometer translate substrate, so this has reduced the quantity of the scatterometer that work in-process provided, and increase turnout.

Scatterometer SM1 optical system (not shown) need be adapted to different wavelength coverage to be used.Therefore, adaptive optical element AE1 is set at the suitable position in the optical system of scatterometer, and when selecting different wavelength coverages, under the control of control module CU, carries out essential correction.Adjustable element AE1 can take various form.For example, it can comprise controllably deformable catoptron, controllably deformable lens element, movably lens element, a plurality of lens element, and described relative positions can be adjusted and/or can be removable lens element.

Another scatterometer SM2 as shown in Figure 3 according to an embodiment of the invention.In this device, adopt lens combination 12 to be focused by the radiation that radiation source 2 sends, focus on the substrate W by 16 reflections of partial reflection surface and via micro objective 15 with high-NA (NA) (wishing at least 0.9 or at least 0.95) by interference filter 13 and polarizer 17.Immersion scatterometer even can have surpasses the lens of 1 numerical aperture.Then, institute's radiation reflected is transmitted into detecting device 18 by partial reflection surface 16, so that detect scattering spectrum.Detecting device can be located on the back projection pupil plane 11 at focal length place of lens 15, yet pupil plane can be alternatively with auxiliary optical element (not shown) imaging once more on detecting device 18.Described pupil plane is that the radial position of radiation thereon limits incident angle and azimuthal plane of position, angle qualification radiation.Described detecting device wishes it is two-dimensional detector, so that can measure the bidimensional angle scattering spectrum intensity measurements of the function of scattering angle (promptly as) of substrate target.Detecting device 18 can be for example charge-coupled device (CCD) or complementary metal oxide semiconductor (CMOS) (CMOS) sensor, and can have the integral time of 40 milliseconds of for example every frames.

Be often used in the intensity of for example measuring incident radiation with reference to bundle.For this reason, when radiation beam incided on the partial reflection surface 16, the part of radiation beam was restrainted towards reference mirror 14 transmissions as reference by described surface.Then, described reference bundle is projected on the different piece of same detecting device 18.

One or more interference filters 13 be used in as 405-790nm or even the scope of lower for example 200-300nm in select interested wavelength.Interference filter can be tunable rather than comprise a different set of optical filter.Replace one or more interference filters, can use grating, or except one or more interference filters, also can use grating.

Detecting device 18 can be measured the intensity of the radiation that is scattered of single wavelength (or narrow wavelength coverage), independent intensity at a plurality of wavelength, perhaps all-in-one-piece intensity on wavelength coverage.And then detecting device can be measured the intensity and/or the phase differential between transverse magnetic polarized radiation and transverse electric polarized radiation of transverse magnetic (TM) polarized radiation and transverse electric (TE) polarized radiation individually.

Can adopt the broadband radiation source 2 that provides big etendue (etendue) (be radiation source 2 have wide radiation frequency or wavelength coverage and be colored thus), allow the mixing of multi-wavelength.A plurality of wavelength on the broadband need the space of each bandwidth with δ λ and at least 2 δ λ (being the twice of wavelength bandwidth).A plurality of radiation " source " can be by the different piece of the expansion radiation source of cutting apart with for example fibre bundle.By this way, carrying out scattering spectra that angle decomposes can be measured on a plurality of wavelength concurrently.Can measure the three-dimensional spectrum (wavelength and two different angles) that comprises more information than two-dimensional spectrum.This allows more information measured, and this increases the robustness of metrology process.This has carried out more detailed description in U.S. Patent Application Publication No.US2006-0066855, the document integral body by reference is incorporated herein.

As about described in the described embodiment of Fig. 2, the radiation that radiation source 2 can be used to launch the selectable wavelength (or set of wavelengths) that has in first wavelength coverage or second wavelength coverage by control module CU control.According to selected scope, adjustable element AE2 Be Controlled is used to realize the essential compensation of optical system.Radiation source 2 and adjustable element AE2 can adopt and the identical form of corresponding components in the described embodiment about Fig. 2.In conjunction with the wavelength coverage of exporting by described source 2 or the selection of group, one or more wave filters 13 are exchanged or are adjusted.

As shown in the figure, adjustable element AE2 is set in the measurement branch road of scatterometer SM2, that is, between sample and detecting device 18, but alternately be set in the irradiation branch road (promptly between radiation source 2 and described sample).At least two adjustable element can be provided, and for example every branch road is one.Adjustable element AE2 also can be set in the high-NA objective 15.

Scatterometer SM3 according to another embodiment of the invention as shown in Figure 4.In this embodiment, two radiation sources 31,32 provide the have orthogonal polarization state radiation beam of (for example p and s), described radiation beam scioptics 33 and 34 to be focused forming empty radiation source, and by polarization beam apparatus 35 combinations.As mentioned above, each radiation source may command is used to be transmitted in the radiation in first or second wavelength coverage.Orifice plate 20 can be provided with one or more holes, is used for described irradiation beam is shaped as for example conventional, ring-type and/or multipole irradiation beam.Selection mechanism 23, motor for example can be used to select in a plurality of holes of described plate.

Relay optics 36,37 projects on the substrate W that is kept by substrate table WT measuring hot spot via unpolarized beam splitter 39 and object lens 40.Catoptron 38 can be out of shape under the control of control module CU (not shown), to realize and the synchronous essential aberration correction of selected wavelength coverage of exporting by radiation source 31,32.Object lens 40 have high-NA, and for example greater than 0.9 or 0.95, so that it forms pupil plane PP in inside, this is arrived on the detecting device 45 (for example ccd array or other forms of camera) by scioptics 42 and 43 reimagings.Movably the edge of a knife or knife edge 44 provide for focusing.

Unpolarized beam splitter 39 with the part of incoming beam via catoptron 46 and lens 47, be directed on the reference mirror 48, from described reference mirror 48, described radiation beam returns and is guided towards camera 45, forming, thereby make the effect of variation of any radiation source intensity be removed with reference to hot spot.

Scatterometer SM4 according to another embodiment of the invention as shown in Figure 5.This scatterometer is identical with above-mentioned scatterometer SM3 major part, and therefore the description of common unit is omitted.

Substitute deformable catoptron 38, scatterometer SM4 has simple folding mirror 38a, and described folding mirror 38a can be by half silver-plated (half-silvered), to connect or coupling in the irradiation that is used for the focusing system (not shown).In order to realize the essential correction of optical system according to selected wavelength coverage, two (or more a plurality of) removable objective lens 40a, 40b provide actuator 40c together, to realize the exchange of object lens.One of them each wavelength coverage for described radiation source 31,32 outputs of removable object lens (or group) is optimised.Scheme as an alternative, adjustable element also can be set in the object lens 40 of high-NA.

In any above-mentioned scatterometer, the target on substrate W can be printed grating, so that after developing, striped is formed by real resist line.Described striped can be alternatively etched advances described substrate.Target pattern is selected as for parameters of interest (for example focus in the lithographic projection apparatus, dosage, overlapping, aberration etc.) sensitivity, so that the variation of correlation parameter will be expressed as the variation of printed target.For example, target pattern can be to the aberration sensitivity in the lithographic projection apparatus especially optical projection system PL, and the existence of illumination symmetry (illumination symmetry) and this aberration will self be expressed as the variation of printed target pattern.Correspondingly, the scatterometry data of the target pattern of being printed are used to rebuild described target pattern.The parameter of described target pattern (for example live width and linear) can be imported in the process of reconstruction, and described process of reconstruction is realized according to the knowledge of printing step and/or other scatterometry programs (scatterometry processes) by processing unit PU.

There are two kinds of basic skills that are used for determining the parameters of interest value (for example CD) of target: iteration modeling and library searching according to the data (being called spectrum) that obtain from scatterometer.In the iteration modeling technique, the theoretical model of object construction is used to calculate the spectrum as the function of parameters of interest that obtains from target.Begin with initial value or seed numerical value, the spectrum of predicting is calculated and is compared with the spectrum that measures, so that can improve the estimation of parameter value.This process repeats for iteration repeatedly, mate in the required limit of error or scope (margin) up to spectrum of predicting and the spectrum that measures, at this point, suppose that the actual value of parameter equates with the parameter value of predicting that is used for the spectrum that acquisition is predicted in required accuracy rating.

In library searching, adopt the model that spectrum is related with parameter value once more, the library of spectra of predicting is rebuilt, and measured spectrum compared with the clauses and subclauses in storehouse, to determine immediate coupling.The scope of the quantity of the clauses and subclauses in the described storehouse by desired possible parameter value determine, the scope of described possible parameter value depends on parameter value and can be in advance how be accurately inferred and required measuring accuracy.

The another kind of technology that can be used in the scatterometry (scatterometry) is principal component analysis (PCA) (Principal Component Analysis/PCA).With this technology, the matrix of test or calibrating pattern is printed under the situation that changes the parameters of interest value.Spectrum obtains at each test pattern, and analyzedly is used to release one group of major component (principal components) (basic function), so that each spectrum can be expressed as one group of coefficient that multiplies each other with major component.Then according to the known parameter value of test pattern, can derive the function that described coefficient and described parameter value are got in touch.The spectrum that draws according to measurement target is broken down into one group of coefficient that multiplies each other with major component, and described coefficient value is used for determining described parameter value.

In order to ensure the precision in scatterometry, need guarantee that optical system is aberrationless in the required limit.This need measure the aberration in the optical system.The conventional route of measuring the aberration in the optical system (optical system that for example is used for scatterometer) is an interferometry.Yet, the hardware that interfere measurement technique need add, and very consuming time, and be difficult on equipment just in use, realize.Correspondingly, period regulation and diagnostic monitoring carry out under the situation in long period not using one section of scatterometer.

Although in this article can be specifically with reference to the use that described lithographic equipment is used to make IC, but be to be understood that lithographic equipment described here can have other application, for example, manufacturing of the guiding of integrated optics system, magnetic domain memory and check pattern, flat-panel monitor, LCD, thin-film head etc.It should be appreciated to those skilled in the art that in the context of this alternative application, any use of term " wafer " or " tube core " here can be thought respectively and more upper term " substrate " or " target part " synonym.Here the substrate of indication can be handled before or after exposure, for example in track (track) (a kind ofly typically resist layer is coated onto on the substrate, and the instrument that the resist that has exposed is developed), measurement facility and/or the instruments of inspection, handle.Under applicable situation, disclosure herein can be applied in this and other substrate processing instruments.In addition, more than described substrate can be handled once, for example, make described term substrate used herein also can represent to have comprised the substrate of a plurality of processing layers for producing multilayer IC.

Although below specifically with reference in the context of optical lithography, using embodiments of the invention, it should be understood that the present invention can be used for other and use, for example imprint lithography, and the situation of needing only allows, and is not limited to optical lithography.In imprint lithography, the profile that pattern forms device defines the pattern that produces on substrate.The profile that described pattern can be formed device is printed in the resist layer that offers described substrate, makes up described resist is solidified by applying electromagnetic radiation, heat, pressure or its thereon.After described resist solidified, described pattern formed device and removes from described resist, and stays pattern in resist.

Term used herein " radiation " and " bundle " comprise the electromagnetic radiation of all types, comprise: UV radiation (for example have about 365,355,248,193,157 or the wavelength of 126nm) and extreme ultraviolet radiation (for example having the wavelength in the 5-20nm scope), and the particle beams, for example ion beam or electron beam.

Under the situation that situation allows, any in various types of opticses or their combination can be represented in described term " lens ", comprises refraction type, reflective, magnetic, electromagnetic type and electrostatic optics.

Although below described certain embodiments of the present invention, it should be understood that the present invention can realize with above-mentioned different form.For example, the present invention can take to comprise the form of the computer program of the one or more sequence of machine-readable instruction of describing above-mentioned disclosed method, perhaps take to have the form of the data storage medium (for example, semiconductor memory, disk or CD) of this computer program of storage therein.

Above description is illustrative, rather than restrictive.Therefore, it will be understood by those of skill in the art that and under the condition of the protection domain that does not deviate from appended claim, can make amendment the present invention.

Claims (20)

1. inspection machine, described inspection machine configuration be used for determining with by being used for being printed on the value of the parameter correlation of the target pattern on the substrate in the photoetching process of making device layer on the substrate, described equipment comprises:

Radiation source is provided for launching selectively first radiation beam with first wavelength in first wavelength coverage, perhaps has second radiation beam of second wavelength in second wavelength coverage, and described second wavelength coverage is different from described first wavelength coverage;

Optical system, one that is provided for being selected in first or second radiation beam is directed on the target pattern, and will by the tomographic projection of target pattern break-in to the detecting device to obtain the spectrum of scatterometer spectrum or scatterometry; And

Adjustable optical element, being provided for launching first radiation beam according to radiation source selectively still is second radiation beam, realizes the aberration correction of optical system.

2. equipment according to claim 1, wherein said first wavelength coverage are 5 to 300nm.

3. equipment according to claim 1, wherein said second wavelength coverage are 400 to 800nm.

4. equipment according to claim 1, wherein said first radiation beam comprises a plurality of components or composition, wherein each component or composition have the wavelength separately in first wavelength coverage.

5. equipment according to claim 1, wherein said second radiation beam comprises a plurality of components or composition, wherein each component or composition have the wavelength separately in second wavelength coverage.

6. equipment according to claim 1, wherein said first radiation beam is the broadband radiation bundle, described broadband radiation bundle is included in the wavelength of the certain limit in first wavelength coverage.

7. equipment according to claim 1, wherein said second radiation beam is the broadband radiation bundle, described broadband radiation bundle is included in the wavelength of the certain limit in second wavelength coverage.

8. equipment according to claim 1, wherein said adjustable lay the grain are learned element and are comprised deformable mirror.

9. equipment according to claim 1, wherein said adjustable lay the grain element comprises can adjust the refractor element.

10. equipment according to claim 1, wherein said adjustable lay the grain are learned element and are comprised refractor element and actuator, and described actuator is provided for adjusting the position and/or the direction of described refractor element.

11. equipment according to claim 1, wherein said adjustable lay the grain are learned element and comprised a pair of refractor element and actuator, described actuator is provided for adjusting described a pair of refractor relative positions.

12. equipment according to claim 1, wherein said adjustable lay the grain are learned element and comprised a plurality of removable optical elements and actuator, described actuator is provided for selectively one in the described replaceable optical element being positioned in the optical system.

13. equipment according to claim 1, wherein said optical system comprises irradiation branch road and detection branch, described irradiation branch road is provided for selected of going out in first or second radiation beam is directed on the target pattern, and described detection branch be provided for by the tomographic projection of described target pattern break-in to detecting device, to obtain the spectrum of scatterometer spectrum or scatterometry, wherein said adjustable optical element is set in the irradiation branch road.

14. equipment according to claim 1, wherein said optical system comprises irradiation branch road and detection branch, described irradiation branch road is provided for selected of going out in first or second radiation beam is directed on the target pattern, and described detection branch be provided for by the tomographic projection of described target pattern break-in to detecting device, to obtain the spectrum of scatterometer spectrum or scatterometry, wherein said adjustable optical element is set in the detection branch.

15. equipment according to claim 1, wherein said optical system comprises objective system, and adjustable lay the grain element is set in the objective system.

16. equipment according to claim 1, wherein said adjustable lay the grain are learned element and comprise a plurality of object lens that can locate selectively in optical systems.

17. a lithographic equipment comprises:

Illuminating optical system is provided for irradiation pattern;

Projection optical system is provided for image projection with described pattern to substrate; And

Inspection machine, described inspection machine configuration are used for determining and by being used for being printed in the photoetching process of making device layer on the substrate value of the parameter correlation of the target pattern on the substrate, described equipment comprises:

Optical system, be provided for to have first radiation beam of first wavelength in first wavelength coverage, second radiation beam that perhaps has second wavelength in second wavelength coverage is directed on the target pattern, and will by the tomographic projection of described target pattern break-in to the detecting device to obtain the spectrum of scatterometer spectrum or scatterometry, described second wavelength coverage is different from described first wavelength coverage, and

Adjustable optical element, being provided for still is that second radiation beam is guided by optical system according to first radiation beam selectively, realizes the aberration correction of described optical system.

18. a lithographic cell comprises:

Coating machine is provided for being substrate coating radiation-sensitive layer;

Lithographic equipment is provided for image exposure to the radiation-sensitive layer of the substrate that is coated with by described coating machine;

Developer is provided for the image that is exposed by lithographic equipment is developed; And

Inspection machine, described inspection machine configuration are used for determining and by being used for being printed in the photoetching process of making device layer on the substrate value of the parameter correlation of the target pattern on the substrate, described equipment comprises:

Radiation source is provided for launching selectively first radiation beam with first wavelength in first wavelength coverage, perhaps has second radiation beam of second wavelength in second wavelength coverage, and described second wavelength coverage is different from described first wavelength coverage;

Optical system, one that is provided for being selected in first or second radiation beam is directed on the target pattern, and will by the tomographic projection of target pattern break-in to the detecting device to obtain the spectrum of scatterometer spectrum or scatterometry; And

Adjustable optical element, being provided for launching first radiation beam according to radiation source selectively still is second radiation beam, realizes the aberration correction of optical system.

19. one kind be used for determining with by being used for being printed on the method for inspection of value of the parameter correlation of the target pattern on the substrate in the photoetching process of making device layer on the substrate, described method comprises:

The control radiation source is launched first radiation beam with first wavelength in first wavelength coverage selectively, perhaps has second radiation beam of second wavelength in second wavelength coverage, and described second wavelength coverage is different from described first wavelength coverage;

Adopt optical system that of selecting in first radiation beam or second radiation beam is directed on the target pattern, and will be by the tomographic projection of target pattern break-in to detecting device, to obtain the spectrum of scatterometer spectrum or scatterometry; And

Adjusting adjustable optical element, still is the aberration correction that second radiation beam is realized optical system selectively to launch first radiation beam according to radiation source.

20. an inspection machine, described inspection machine configuration are used for determining and by being used for being printed in the photoetching process of making device layer on the substrate value of the parameter correlation of the target pattern on the substrate, described equipment comprises:

Optical system, be provided for to have first radiation beam of first wavelength in first wavelength coverage, second radiation beam that perhaps has second wavelength in second wavelength coverage is directed on the target pattern, and will by the tomographic projection of target pattern break-in to the detecting device to obtain the spectrum of scatterometer spectrum or scatterometry, described second wavelength coverage is different from described first wavelength coverage, described optical system comprises object lens and imaging optical system, described object lens have pupil plane and are provided for collecting by the radiation of target pattern break-in, and described imaging optical system is provided for image projection with pupil plane to detecting device; And

Adjustable optical element, being provided for still is that second radiation beam is guided by optical system according to first radiation beam selectively, realizes the aberration correction of described optical system.

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