CN101263430A

CN101263430A - Microlithography projection optical system, method for manufacturing a device and method to design an optical surface

Info

Publication number: CN101263430A
Application number: CNA2006800335441A
Authority: CN
Inventors: H-J·曼恩; W·乌尔里希; M·普莱托里尔斯
Original assignee: Carl Zeiss SMT GmbH
Current assignee: Carl Zeiss SMT GmbH
Priority date: 2005-09-13
Filing date: 2006-09-12
Publication date: 2008-09-10
Anticipated expiration: 2026-09-12
Also published as: DE102006043251A1; CN101263430B

Abstract

In general, in one aspect, the invention features a microlithography projection optical system (101) that includes a plurality of elements (310-360) arranged to image radiation from an object plane (103) to an image plane (102), at least one of the elements being a reflective element that has a rotationally asymmetric surface positioned in a path of the radiation. The rotationally asymmetric surface deviates from a rotationally symmetric surface by about 10 nm or more and the optical system is a microlithography projection optical system.

Description

The method of micro-lithography projection optical system, the method that is used for manufacturing installation and design optical surface

Technical field

The present invention relates to a kind of micro-lithography projection optical system, particularly a kind of projection objective, a kind of micro-lithography instrument of this optical system, a kind of this micro-lithography instrument that uses of comprising come micro-lithography to make the method for micro-structural components, pass through the micro-structural components of this method manufacturing and the method that designs optical surface in this optical system.

Background technology

Projection objective is widely used in the micro-lithography, and it is by being deposited on the suprabasil photosensitive material layer image that forms chopper wheel, and the figure transfer of the dish of self-modulation in the future is to substrate.Usually, projection objective can be divided into three kinds of different classifications: refractive objective lens, reflecting objective and catadioptric objective.Refractive objective lens uses refracting element (for example lens) will arrive the picture plane from the photoimaging of object plane.Reflecting objective uses reflecting element (for example catoptron) will arrive the picture plane from the photoimaging of object plane.Catadioptric objective uses refraction and reflecting element will arrive the picture plane from the photoimaging of object plane simultaneously.

Object lens, especially for the object lens in the optical projection system, can obtain from " Optical systemdesign issues in development of projection camera for EUV lithography " (Proc.SPIE 2437 (1995)) of T.Jewell.Other object lens can obtain from EP0730169A, EP0730179A, EP0730180A, EP0790513A, US 5063586A, US6577443A, US 6660552A and US 6710917A.

Summary of the invention

Target of the present invention is, improves the resolution of optical system under given illumination wavelength, and described optical system especially can be used as the projection objective in the microlithographic projection exposure device.In addition, optical system according to the present invention should have higher light percent of pass with respect to irradiates light.

The optical system of the feature of this target by having claim 1 realizes.

In the following description, rotation asymmetric surface according to the present invention also is called the free type curved surface.Unlike sphere or aspheric surface border, the free type curved surface does not have rotation axes of symmetry.According to free type curved surface of the present invention, being different from the known aspheric surface that is used for the EUV projection objective rotates symmetrical minute surface part and is, described known aspheric surface rotating mirror surface is described by mathematical Taylor expansion, promptly has the sag that is provided by rotational symmetric n rank polynomial expression.The central point that is used for all these polynomial Taylor expansions limits by shared optical axis.Because Taylor expansion is calculated easily, optimize easily and in such minute surface manufacturing, have a large amount of experiences, so existing minute surface is described by this expansion.Yet the inventor recognizes that existing Taylor expansion with common center can cause undesirable distortion, and can not be reduced to below the specified level.When according to the present invention, when one of optical surface is embodied as free type or rotation symmetrical surface, can avoid rotating symmetrical optical surface intrinsic described distortion restriction.Use the free type curved surface, can overcome the rotation symmetrical surface intrinsic numerical aperture and the restriction of distortion, this is especially favourable in EUV micro-lithography protection field.In certain embodiments, the free type curved surface can be the surface about the meridian ellipse minute surface symmetry of optical system.Meridian ellipse is limited by the aperture of the optical element of the central point of the normal of object plane and thing field and optical system.Advantageously, projection objective according to the present invention is the reflective projection object lens.Usually, the picture plane parallel of optical system is in object plane.Optical system can have the zone that minimum profile curvature radius is 300mm as the plane.In optical system, at the object plane place, chief ray can be about 3 °, 5 °, 7 ° or bigger angle with respect to the object plane normal.Optical system can have and is positioned at apart from object plane for surpassing 2.8m, particularly surpassing the entrance pupil at 10m place.Usually, in the optical system with free type curved surface, accurately the pupil plane that limits is non-existent.On the pupil plane of optical system, the chief ray of putting with respect to different fields compiles.On the pupil plane, superimposed from the light of each point.Term pupil plane is used for representing the zone perpendicular to the light that guides in optical system, and wherein, light distribution distributes corresponding to the irradiating angle in object plane.The light of imaging can be from being positioned at the object reflection of object plane.The object that is positioned at object plane can be the chopper wheel that is imaged onto the picture plane by a plurality of elements.This optical system can have the minification of 4X.Can comprise four or more reflecting element according to optical system of the present invention.Particularly, described optical system can comprise six or more a plurality of reflecting element.A plurality of elements can be set to be used for photoimaging to the intermediate image plane between object plane and picture plane.In this case, field stop can be placed on the intermediate image plane place or near.Particularly, a plurality of elements can comprise five elements, and along the light path from object plane to the picture plane, intermediate image plane can be between the 4th and the 5th element.Object plane and be separated by as the plane and be approximately 1m or bigger distance L.From object plane to the optical path length as the plane approximately is 2L, 3L, 4L or bigger.A plurality of elements can comprise at least one pair of adjacent elements on light path, wherein this is to the at interval about 0.5L or more of adjacent elements.Advantageously, the neither one element can cause blocking of outgoing pupil in a plurality of element.Described a plurality of element can comprise first catoptron and second catoptron, and described first catoptron and second catoptron have apart from object plane and be respectively d ₁And d ₂Minor increment, d wherein ₁/ d ₂Approximately be 2 or bigger.Optionally, d ₁/ d ₂Also can be less than 2.In this case, optical system has big operating distance in object lens one side usually.Described a plurality of element can comprise first element from object plane on as the light path on plane, wherein first element has positive focal power.This optical system can comprise the aperture diaphragm between object plane and picture plane.A plurality of elements of this optical system can comprise three elements, and from object plane to the picture light path on plane on, aperture diaphragm can second and three element between.Optionally, aperture diaphragm can be positioned at second or the three element place.Light can be by aperture diaphragm once or twice.Be used for light source according to optical system of the present invention and can be having approximately smaller or equal to 300nm, smaller or equal to 200nm, smaller or equal to the LASER Light Source of 100nm.

Mathematics expansion according to the free type curved surface of claim 2 has provided preferably and repeatably reflecting surface manufacturing.In this expansion, α can be 66.And m can comprise even number, and m+n can be equal to, or greater than 10.

According to the variation of

claim

3 or 4 the object lens distortion suitably is reduced to and is lower than by using the accessible limit of the symmetrical optical surface of rotation.One or more position, the rotation symmetrical surface can depart from about 100 λ of only rotation symmetrical surface or bigger.One or more position, the rotation symmetrical surface can depart from the about 50nm of only rotation symmetrical surface or bigger, 100nm or bigger, 500nm or bigger, 1000nm or bigger.

Reduced the manufacturing requirement of free type optical surface according to the free type optical surface of the minute surface symmetry of claim 5.

Two reflecting elements with free type optical surface according to claim 6 cause the minimized possibility of better aberration on the one hand, and make that can and satisfy particular aberration with less complexity minimizes requirement ground manufacturing Free Surface.This optical system also can comprise three, four, five or six free type elements.

According to the optical system of the reflecting element that is no more than the positive chief ray angle magnification of two have comprising of claim 7, relatively low angle of incident light appears on catoptron, therefore make lower aberration is arranged at starting end.This especially be to use according to Claim 8 only comprise a optical system with reflecting element of positive chief ray angle magnification.

Numerical aperture according to the optical system of claim 9 allows high resolving power.The numerical aperture of picture side can be up to 0.25,0.28,0.3,0.35,0.4 or bigger.

Image field size according to claim 10 allows effective optical system of using in the micro-lithography projection arrangement.When improving aberration correction by the free type curved surface, have the possibility that is designed to of rectangle image field now, this design can not adapt to the requirement of appointment showing too high aberration when using the rotation symmetrical surface.This rectangular field can have the minimum dimension of about 2mm, and can have about first dimension and about second dimension more than or equal to 1mm more than or equal to 1mm, and wherein first and second dimensions are quadratures.Second dimension can be for about 10mm or approximately more than or equal to 20mm.

Make projection quality only by diffraction according to the distortion of claim 11 with according to the wavefront error of claim 12, i.e. projection light wavelength, limit.Particularly, the optical system with so low distortion preferably use 10 and the 30nm scope in the EUV light source.

This optical system can have the chief ray that is not parallel to the object plane normal on object plane.Make according to the key light line angle of claim 13, be controlled at light distribution in the illumination optical element before the projection objective, can be controlled at the distribution of the irradiating angle in the picture plane by the optical element that uses low quantity.This point is impossible by the optical system that use is used for the convergence apparatus of chief ray angle, because this will cause the requirement to add ons, distributes by the control of the light distribution on chain of command irradiating angle to obtain chain of command.Dispersing according to having of claim 13 in the optical system of chief ray, object plane is between a plurality of elements and entrance pupil of optical system.

Help avoid high aberration according to the maximum incident angle degree of claim 14 at starting end.Lip-deep maximum incident angle degree at each element can be less than 18 ° or less than 15 °.

Allow the high deviation of the substrate that is provided with on as the plane according to the telecentric optical system of claim 15.

Optical system according to claim 16 allows to obtain very high resolution.Ratio θ/NA can be about 60 or littler, perhaps 50 or littler.

The micro-optic design that the optical system of approximately moving smaller or equal to thing-kine bias of 75mm allows optical system that has according to claim 17.The image skew can be approximately smaller or equal to 50mm, perhaps approximately smaller or equal to 25mm.Under the situation of zero image skew, the axle rotation that optical system can intersect around the central field point with thing and image field need not the conversion of central field point.This uses the occasion advantageous particularly of metering and testing tool when requiring the optical system rotation.

The compact design of the chief ray with small incident degree is provided according to the freeboard (freeboard) of the element of claim 18.Four of optical system or more element can have approximately the freeboard more than or equal to 5mm.This has reduced the support of optical system optical element and the designing requirement of substrate.

The optical system with light source according to claim 19 advantageously utilizes aberration to minimize by using at least one free type surface, because in the wavelength coverage of this light source, aberration and distortion are possible.More preferably, wavelength arrives in the scope of about 15nm at about 10nm.

According to the advantage of the optical system of claim 20 and according to the micro-lithography instrument of claim 21 corresponding to above mentioned various optical systems according to claim 1 to 19.According to the manufacture method of claim 22 with according to the element of claim 23 also is like this.

Provide a kind of repeatably method for designing to make the free type surface that to make with controllable mode according to the method for designing of claim 24.

And embodiment can comprise the advantage that one or more is following.For example, embodiment comprises the reflective projection object lens, and described object lens are being the heart far away as the plane.This can provide the image magnification ratio of constant or approximately constant in as side operating distance scope.

In one embodiment, the refraction projection object lens have high resolution.For example, projection objective can have the ability of resolution less than the structure of about 50nm.High can obtain high resolution in as the projection objective of side numerical aperture having, described object lens are designed to the operation (for example approximately 10nm to about 30nm) under the short wavelength.

Projection objective can provide the image of low aberration, in one embodiment, proofreaies and correct projection objective to obtain about 30m λ or littler wavefront error.In one embodiment, proofread and correct projection objective to obtain to be lower than distortion smaller or equal to about 2nm.

Embodiment comprises such reflecting objective, and it has high numerical aperture, and the imaging that has low pattern distortion, hangs down the disposition far away on wavefront error and the picture plane in bigger image field is provided.These characteristics can obtain by using one or more free type catoptron.

In certain embodiments, no matter how many projection objectives is around the rotation of turning axle, can both easily realize the metering of projection objective.For example, when projection objective rotated around this axle, the embodiment of projection objective (for example, the projection objective of high NA) can obtain less or zero image skew, and this can cause axle to enter the court a little less or not have skew.Therefore, when projection objective rotates, can carry out the metering of repetition at same point, and need not to reset the potential field point.

Embodiment also comprises such reflective projection object lens, and it does not have, and a relevant pupil blocks or the center pupil blocks.

The embodiment of projection objective can be adapted to the operation in the different wavelength coverages, comprises visible and ultraviolet (UV) wavelength.Embodiment also can be adapted to the operation of UV (EUV) wavelength extremely far away.And embodiment can be adapted to more than one wavelength or a wavelength coverage.

The embodiment of reflective projection object lens can be used in the lithography tool (for example photoetching scanner) and low relatively overscanning can be provided.For example, have the projection objective of rectangle image field, can obtain low overscanning by use.In this embodiment, but alignment image is so that the edge of rectangular field is parallel to the leading edge of wafer position, avoid need crossing for the corner of scanning position the leading edge of image field boundary scan wafer position, this often takes place with respect to arc field scan rectangle or square wafer position the time.

Embodiment comprises the lithography tool with high relatively output.For example, have the embodiment of low relatively overscanning, more efficient than comparable system with big overscanning.Thereby the system of these low overscanning can provide higher wafer throughput than comparable system.

In certain embodiments, the reflective projection object lens have low relevant or field-free relevant shade influence.For example, the reflective projection object lens can make its entrance pupil away from object plane (for example infinite distant place), to obtain consistent chief ray lighting angle on the thing field.This can reduce or be avoided a relevant shade influence, the occasion that this influence changes when occurring in chief ray angle by the thing field.Optionally, perhaps in addition, projection objective can have the less variation of the incident angle value of the light in the meridian cross section of less chief ray incident angle value and/or each catoptron in projection objective, by each reflection multilayer lamination of optimizing for described incident angle is provided, can obtain the average reflectance of the increase of each catoptron.

In a particular embodiment, projection objective can comprise such feature, makes the irradiation system complexity reduce.For example, the position of the entrance pupil of projection objective can be positioned at before the object plane.That is to say that the chief ray that originates in different points is dispersed relative to each other.This can make to not be used in the irradiation system and use telescope with the emergent pupil image rotation of the irradiation system position to the entrance pupil of projection objective, and reaches the emergent pupil of the entrance pupil/irradiation system of projection objective.

Other characteristics and advantage will become apparent by following description, figure and claim.

Description of drawings

Fig. 1 is the synoptic diagram of micro-lithography execution of instrument example;

Fig. 2 A is the synoptic diagram of the part of the micro-lithography instrument shown in Fig. 1;

Fig. 2 B is the cross-sectional view on rotation symmetrical surface and corresponding rotation symmetric reference surface;

Fig. 3 is the cross-sectional view at the projection objective embodiment shown in the meridian cross section;

Fig. 4 is the cross-sectional view in the part of the catoptron of the projection objective shown in the meridian cross section;

Fig. 5 A is the light path synoptic diagram that has on the catoptron of positive chief ray angle magnification;

Fig. 5 B is the light path synoptic diagram that has on the catoptron of negative chief ray angle magnification;

Fig. 6 A is the figure of the occupy-place face (footprint) of catoptron;

Fig. 6 B is the cross-sectional view of catoptron shown in Fig. 6 A;

Fig. 7 A is the vertical view of the embodiment of a ring segment field;

Fig. 7 B is the vertical view with respect to the ring segment field of a pair of wafer wafer position;

Fig. 7 C is the vertical view with respect to the rectangular field of a pair of wafer wafer position;

Fig. 8 is the synoptic diagram of the projection objective of micro-lithography execution of instrument example shown in Figure 1;

Fig. 9 is the cross-sectional view at the projection objective shown in the meridian cross section;

Figure 10 is the cross-sectional view in the part of the projection objective shown in the meridian cross section;

Figure 11 is the cross-sectional view at the projection objective shown in the meridian cross section;

Figure 12 is the cross-sectional view at the projection objective shown in the meridian cross section;

Figure 13 is the cross-sectional view at the projection objective shown in the meridian cross section;

Figure 14 A is the cross-sectional view at the projection objective shown in the meridian cross section;

Figure 14 B is the cross-sectional view that comprises the optical system of projection objective shown in Figure 14 A and irradiation system;

Figure 15 is the cross-sectional view at the projection objective shown in the meridian cross section;

Figure 16 A illustrates the x-y vector plot with the distortion of the change in location in the image field that calculates for projection objective shown in Figure 15;

Figure 16 B illustrates the x-y vector plot with the chief ray angle of the change in location in the image field that calculates for projection objective shown in Figure 15;

Figure 17 is the cross-sectional view at the projection objective shown in the meridian cross section;

Figure 18 to 20 illustrates for projection objective shown in Figure 17 lateral aberration with the change in location in the image field;

Figure 21 is the cross-sectional view at the projection objective shown in the meridian cross section;

Figure 22 to 24 illustrates for projection objective shown in Figure 21 aberration along with the change in location in the image field;

Figure 25 is the cross-sectional view at the projection objective shown in the meridian cross section;

Figure 26 to 28 illustrates for projection objective shown in Figure 25 aberration along with the change in location in the image field;

Figure 29 is the cross-sectional view at the projection objective shown in the meridian cross section;

Figure 30 to 32 illustrates for projection objective shown in Figure 29 aberration along with the change in location in the image field;

Figure 33 is the cross-sectional view at the projection objective shown in the meridian cross section;

Figure 34 to 36 illustrates for projection objective shown in Figure 33 aberration along with the change in location in the image field;

Figure 37 is the cross-sectional view at the projection objective shown in the meridian cross section;

Figure 38 to 40 illustrates for projection objective shown in Figure 37 aberration along with the change in location in the image field;

Figure 41 is the cross-sectional view at the projection objective shown in the meridian cross section;

Figure 42 to 44 illustrates for projection objective shown in Figure 41 aberration along with the change in location in the image field;

Figure 45 is the cross-sectional view at the projection objective shown in the meridian cross section;

Figure 46 to 48 illustrates for projection objective shown in Figure 45 aberration along with the change in location in the image field;

Figure 49 is the cross-sectional view at the projection objective shown in the meridian cross section;

Figure 50 illustrates for projection objective shown in Figure 49 aberration along with the change in location in the image field;

Figure 51 is the cross-sectional view at the projection objective shown in the meridian cross section;

Figure 52 is the cross-sectional view at the projection objective shown in the meridian cross section;

Figure 53 is the process flow diagram that shows a kind of manufacturing step of semiconductor device; And

Figure 54 is the process flow diagram that shows the wafer-process step.

Embodiment

On the one hand, the present invention relates to have one or more catoptron reflective projection object lens of (so-called free type catoptron) with free type mirror surface.Reflective projection object lens with free type catoptron can be used in the micro-lithography instrument.With reference to figure 1, micro-lithography instrument 100 generally includes: light source 110, irradiation system 120, projection objective 101 and objective table 130.Show the cartesian coordinate system that is used for reference.Light source 110 sends the light of wavelength X, then light 112 is directed to irradiation system 120.Irradiation system 120 is directed to the chopper wheel 140 that is positioned at object plane 103 with light interaction (for example expansion and homogenising) and with light 122.Projection objective 101 will be from the photoimaging of chopper wheel 140 reflection to the substrate that is positioned at picture plane 102 the surface.Be depicted as light 152 at projection objective 101 as the light of side.For example, as shown in Figure 1, this light is just schematic, and conduct is not with respect to the actual description of the light path of chopper wheel 140.Substrate 150 is supported by objective table 130, and this objective table makes projection objective 101 chopper wheel 140 is imaged onto the different piece of substrate 150 with respect to projection objective 101 mobile substrates 150.

Projection objective 101 comprises axis of reference 105.In the embodiment of projection objective with respect to meridian cross section symmetry, axis of reference 105 is perpendicular to object plane 103 and be positioned at the meridian cross section.

Select light source 110 so that the light of the hope operation wavelength X with instrument 100 to be provided.In certain embodiments, light source 110 is LASER Light Source, for example KrF laser instrument (wavelength that for example, has about 248nm) or ArF laser instrument (wavelength that for example, has about 193nm).Can use non-laser light source, comprise light emitting diode (LED), for example in the blueness or the UV part of electromagnetic wave spectrum, for example about 365nm, about 280nm or about 227nm, radiative LED.

Usually, for the projection objective that is designed in the lithography tool, its af at wavelength lambda is in ultraviolet portion, extreme ultraviolet part or the extreme ultraviolet part of electromagnetic wave spectrum.For example, λ can be for being less than or equal to about 400nm (for example, be less than or equal to about 300nm, be less than or equal to about 200nm, be less than or equal to about 100nm, be less than or equal to about 50nm, be less than or equal to about 30nm).λ can be greater than about 2nm (for example, more than or equal to about 5nm, more than or equal to about 10nm).In an embodiment, λ can be about 193nm, 157nm, 13nm or 11nm.Use short wavelength to wish, because the resolution of projection objective is roughly proportional with wavelength usually.Therefore than the identical projection objective that uses longer wavelength, use short wavelength can make projection objective differentiate littler feature in the picture.Yet in a particular embodiment, λ can be in the non-UV part (for example, visible light part) of electromagnetic wave spectrum.

Irradiation system 120 comprises and is placed the optical element that has the calibration light of even light distribution with composition.Irradiation system 120 also comprises light guided optical part far away usually, so that light 122 is directed to chopper wheel 140.In certain embodiments, irradiation system 120 also comprises the element of the hope polarisation distribution that is used to provide light.

Usually, object plane 103 is parallel to picture plane 102.Yet, in a particular embodiment, tilt with respect to object plane 103 as plane 102.For example, as plane 102 can tilt more than or equal to about 1 ° angle (for example, more than or equal to about 2 °, more than or equal to about 3 °, more than or equal to about 4 °, more than or equal to about 5 °).

Object plane 103 and picture plane 102 spacing distance L, this distance also refers to the longitudinal size or the track lenth of projection objective 101.Track lenth is limited by the distance between two parallel planes.First plane is an object plane, and second is defined as the parallel plane nearest apart from object plane, makes thing field, image field and optical element all between these two parallel planes.Usually, this distance depends on the specific design of projection objective 101 and the operation wavelength of instrument 100.In certain embodiments, for example be in the instrument of EUV lithography design, L (for example, arrives in the scope of about 2.5m at about 1.5m) in the scope of about 3m at about 1m.In a particular embodiment, L is less than 2m, as is less than or equal to about 1.9m (for example, be less than or equal to about 1.8m, be less than or equal to about 1.7m, be less than or equal to about 1.6m, be less than or equal to about 1.5m).L is comparable, and to be greater than or equal to 0.2m bigger (for example, more than or equal to about 0.3m, more than or equal to about 0.4m, more than or equal to about 0.5m, more than or equal to about 0.6m, more than or equal to about 0.7m, more than or equal to about 0.8m, more than or equal to about 0.9m, more than or equal to about 1m).

The optical path length of imaging and the ratio of track lenth change according to the specific design of projection objective 101.In certain embodiments, the ratio of optical path length and track lenth can be higher.For example, the ratio of optical path length and track lenth can be approximately to be greater than or equal to 2 (for example, approximately to be greater than or equal to 2.5, approximately be greater than or equal to 3, approximately be greater than or equal to 3.5, approximately be greater than or equal to 4, approximately be greater than or equal to 4.5, approximately be greater than or equal to 5).

Projection objective 101 has amplification ratio, promptly refers to the ratio of the size of entering the court at object plane 103 and corresponding size of entering the court as plane 102.Usually, the projection objective that is used for lithography tool is the reduced projection object lens, and this represents that they reduce size of images or have dwindled image.Therefore, in certain embodiments, compare with the size on the object plane 103, projection objective 101 can generate size on as plane 102 and more than or equal to about 2 times (for example reduce, more than or equal to about 3 times, more than or equal to about 4 times, more than or equal to about 5 times, more than or equal to about 6 times, more than or equal to about 7 times, more than or equal to about 8 times, more than or equal to about 9 times, more than or equal to about 10 times).That is to say, projection objective 101 more than or equal to about 2 times minification (for example can have, more than or equal to about 3 times, more than or equal to about 4 times, more than or equal to about 5 times, more than or equal to about 6 times, more than or equal to about 7 times, more than or equal to about 8 times, more than or equal to about 9 times, more than or equal to about 10 times).Yet more generally, projection objective can be designed to provide the picture or the picture identical with dimension of object of amplification.

Also with reference to figure 2A, light 152 limits light cone, and it has constituted the chopper wheel image on as plane 102.The angle of light cone is relevant with the picture side numerical aperture (NA) of projection objective 101.Can be expressed as side NA:

NA＝n _osinθ _max

N wherein _oThe refractive index of the surperficial adjacent immersing medium of finger and substrate 150, θ _MaxIt is half-angle degree from the maximum light cone of the imaging light of projection objective 101.

Usually, projection objective 101 can have picture side NA more than or equal to about 0.1 (for example, more than or equal to about 0.15, more than or equal to about 0.2, more than or equal to about 0.25, more than or equal to about 0.28, more than or equal to about 0.3, more than or equal to about 0.35).In certain embodiments, projection objective 101 has higher picture side NA.For example, in certain embodiments, projection objective 101 can have picture side NA greater than 0.4 (for example, more than or equal to about 0.45, more than or equal to about 0.5, more than or equal to about 0.55, more than or equal to about 0.6).Usually, the resolution of projection objective 101 changes according to wavelength X and picture side NA.

Do not wish to be bound by theory, the resolution of projection objective can determine that its formula is based on wavelength and picture side NA:

R = k \frac{λ}{NA},

Wherein R is the minimum dimension that can print, and k is the dimensionless constant that is called technological factor.K changes according to the different factors relevant with optical radiation (for example, polarizability), illumination characteristic (for example, partial coherence, annular irradiation, dipole device, four utmost point devices etc.) and anticorrosive additive material.Usually, k is about 0.4 in about 0.8 the scope, but also can be lower than 0.4 or be higher than 0.8 in some applications.

Projection objective 101 also is the nominal heart far away on as the plane.For example, on the picture exposure field on plane, the chief ray that is parallel to each other can depart from be less than or equal to about 0.5 ° (for example, be less than or equal to about 0.4 °, be less than or equal to about 0.3 °, be less than or equal to about 0.2 °, be less than or equal to about 0.1 °, be less than or equal to about 0.05 °, be less than or equal to about 0.01 °, be less than or equal to about 0.001 °).Therefore, projection objective 101 can provide fully constant magnification in as the operating distance of size.In certain embodiments, chief ray nominal ground is perpendicular to picture plane 102.Therefore, the uneven shape of crystal column surface or can not cause distortion or the shade influence of picture on the plane as defocusing of plane.

In a particular embodiment, projection objective 101 has high relatively resolution (that is, the value of R can be less).For example, R can be and is less than or equal to about 150nm and (for example, is less than or equal to about 130nm, be less than or equal to about 100nm, be less than or equal to about 75nm, be less than or equal to about 50nm, be less than or equal to about 40nm, be less than or equal to about 35nm, be less than or equal to about 32nm, be less than or equal to about 30nm, be less than or equal to about 28nm, be less than or equal to about 25nm, be less than or equal to about 22nm, be less than or equal to about 20nm, be less than or equal to about 18nm, be less than or equal to about 17nm, be less than or equal to about 16nm, be less than or equal to about 15nm, be less than or equal to about 14nm, be less than or equal to about 13nm, be less than or equal to about 12nm, be less than or equal to about 11nm, for example about 10nm).

The quality of the picture that forms by projection objective 101 can quantize in various mode.For example, can characterize picture based on picture measurement or the calculation deviation under the ideal conditions relevant with Gaussian optics.These deviations are common so-called aberrations.A kind of tolerance that is used to quantize with the wavefront deviation of desirable or imagination figure is root mean square wavefront error (W _Rms).W _RmsBe defined in " optics handbook " (volume 1, second edition, Michael Bass are edited (McGraw-Hill, Inc., 1995), the page number 35.3), it is incorporated herein by reference.Usually, the W of object lens _RmsBe worth lowly more, more little with the wavefront deviation of hope or desirable figure, picture quality is also good more.In a particular embodiment, projection objective 101 is for having less W as the picture on the plane 102 _RmsFor example, projection objective 101 can have the W that is less than or equal to 0.1 λ _Rms(for example, be less than or equal to about 0.07 λ, be less than or equal to about 0.06 λ, be less than or equal to about 0.05 λ, be less than or equal to about 0.045 λ, be less than or equal to about 0.04 λ, be less than or equal to about 0.035 λ, be less than or equal to about 0.03 λ, be less than or equal to about 0.025 λ, be less than or equal to about 0.02 λ, be less than or equal to about 0.015 λ, be less than or equal to about 0.01 λ, for example about 0.005 λ).

The tolerance that another kind is used to assess the picture element amount is called the curvature of field.The curvature of field refers to the peak-paddy distance of the spot correlation position, field of focal plane.In certain embodiments, projection objective 101 is for having the less curvature of field as the picture on the plane 102.For example, projection objective 101 can have the picture side curvature of field (for example, be less than or equal to about 30nm, be less than or equal to about 20nm, be less than or equal to about 15nm, be less than or equal to about 12nm, be less than or equal to 10nm) that is less than or equal to about 50nm.

Another tolerance that is used to assess optical property is called distortion.Distortion refers to a little correspondingly depart from the maximum value of ideal image point position entering the court as the plane.In certain embodiments, projection objective 101 can have less maximum distortion.For example, projection objective 101 can have the maximum distortion that is less than or equal to about 50nm and (for example, is less than or equal to about 40nm, be less than or equal to about 30nm, be less than or equal to about 20nm, be less than or equal to about 15nm, be less than or equal to about 12nm, be less than or equal to 10nm, be less than or equal to 9nm, be less than or equal to 8nm, be less than or equal to 7nm, be less than or equal to 6nm, be less than or equal to 5nm, be less than or equal to 4nm, be less than or equal to 3nm, be less than or equal to 2nm, for example 1nm).

And in a particular embodiment, distortion can change less amount at image field.For example, distortion can change at image field and to be less than or equal to about 5nm (for example, be less than or equal to about 4nm, be less than or equal to about 3nm, be less than or equal to about 2nm, be less than or equal to about 1nm).

As a reflecting system, projection objective 101 comprises a plurality of catoptrons, and it is set to, and to form the mode of the picture of chopper wheel 140 on substrate 150 surfaces, will be directed on the substrate 150 from the light of chopper wheel 140 reflections.The specific design of projection objective is described below.Yet more generally, the quantity of catoptron, size and structure depend on the optical characteristics of hope of projection objective 101 and the physical restriction of instrument 100 usually.

Usually, the number could varyization of the catoptron in the projection objective 101.Usually, the number of catoptron is relevant with the various performance balances of the optical property feature that relates to object lens, the optical property feature of described object lens for example is, the percent of pass of wishing (for example, that from the light intensity of thing, its imaging on picture plane 102), wishes blocks as side NA and relevant image resolution ratio and the maximum pupil of hope.

Usually, projection objective 101 (for example has at least 4 catoptrons, more than or equal to 5 catoptrons, more than or equal to 6 catoptrons, more than or equal to 7 catoptrons, more than or equal to 8 catoptrons, more than or equal to 9 catoptrons, more than or equal to 10 catoptrons, more than or equal to 11 catoptrons, more than or equal to 12 catoptrons).In certain embodiments, when hope was positioned at the catoptron of all object lens between object plane and the picture plane, object lens 101 had even number catoptron (for example, 4 catoptrons, 6 catoptrons, 8 catoptrons, 10 catoptrons) usually.In a particular embodiment, when all catoptrons of projection objective all are placed between object plane and the picture plane, also can use the odd number catoptron.For example, when one or more catoptron during with bigger angle tilt, and when all catoptrons all were placed between object plane and the picture plane, projection objective can comprise the odd number catoptron.

Usually, at least one has rotation symmetry or free type curved surface in the catoptron of projection objective 101.Unlike sphere or non-spherical reflector, the free type minute surface does not have rotation axes of symmetry.Usually, rotation symmetric reference face (for example, sphere or aspheric surface rotation symmetric reference surface), the rotation symmetrical surface of match rotation asymmetric surface like this reference surface refers to are recently departed from the free type surface.

Rotation symmetric reference surface can followingly be determined with respect to the free type minute surface.At first, obtain to characterize the information of the free type minute surface of considering.In the embodiment of the optical data of known catoptron, this information comprises cone constant, the k of the basic radius of determining catoptron (for example, 1/c, wherein c is a vertex curvature), catoptron and characterizes the multinomial coefficient of catoptron.Selectively be that perhaps in addition, the information that characterizes catoptron can obtain (for example, using interferometer to obtain) from the surfacial pattern of mirror surface is measured.Surfacial pattern is measured the function z ' can provide a description mirror surface (x ', y '), and wherein z ' is a mirror surface along the sag of the z ' axle of different (x ', y ') coordinate, shown in Fig. 2 B.Initial step also comprises the occupy-place face of determining catoptron, i.e. the actual mirror surface zone that is used for optical reflection imaging in object lens.This occupy-place face can obtain by the reflector area of using the ray trace program to follow the tracks of the light by object lens and to extract the light contact.

After having obtained to characterize the information of rotation asymmetric surface feature, can set up this surperficial local coordinate system, off-centre and inclination that wherein should the surface be zero.Set the inclination on this surface and eccentric provide the starting point of better definition to optimized Algorithm, described optimized Algorithm is determined reference surface and definition z ' axle, along this axle, can determine that the sag between mirror surface and reference surface is poor.Under the situation of the optical data of known mirror surface, z ' axle can be determined based on cone constant, k and basic radius, 1/c.For the rotation symmetric part of optical data, z ' axle is the antimeric axis of symmetry of rotation of rotation asymmetric surface.In the embodiment that mirror surface characterizes with the surfacial pattern measurement, z ' axle is corresponding to metering axle (for example interfering optical axis).Fig. 2 B shows this point for the two dimension part of the asymmetric catoptron 201 of rotation, and wherein local coordinate system is expressed as x ', y ' and z ' axle.Rotate the x of the occupy-place face boundary representation of asymmetric catoptron 201 for the xsect among Fig. 2 B _MinAnd x _Max

Can set up initial reference surface with respect to this coordinate system then.This initial reference surface has zero and tilts and zero off-centre.This initial reference surface or spherical surface or rotate symmetrical aspheric surface.This initial reference surface is set up by the rotation symmetrical surface of specifying the asymmetric minute surface of approximate rotation.This initial reference surface provides starting point to optimized Algorithm.In case set up the initial reference surface, determine along the z ' axle of local coordinate system measure at the local distance bi (i=1...N) between a plurality of points on initial reference surface and a plurality of points that rotate asymmetric surface occupy-place face surface.Next step determines local distance (d by using a plurality of suitable parameters and suitable algorithm _i) minimum value, and set up rotation symmetric reference surface (surface 211 among Fig. 2 B).On rotation symmetric reference surface is under the situation of spherical surface, and described parameter comprises ball centre position, the radius in local coordinate system of reference surface.In Fig. 2 B, the off-centre of ball centre range coordinate initial point is by coordinate x _cAnd z _cIllustrate (along the offset y of y ' axle _cIn Fig. 2 B, do not illustrate).The radius of spherical surface is set at R, according to following formula, and parameters optimization R, x _c, y _cAnd z _cSo that local distance d to be provided _iMinimum value:

z’＝(R ²-(x’-x _c) ²-(y’-y _c) ²) ^1/2-z _c，

It is with coordinate (x _c, y _c, z _c) be that center, radius are the formula of the spherical surface of R.

On rotation symmetric reference surface is under the situation of aspheric surface, and above-mentioned parameter can comprise off-centre and inclination, basic radius, cone constant and the non-spherical coefficient of reference surface.These parameters can be determined based on following formula:

z^{'} = \frac{c^{'} h^{2}}{1 + \sqrt{1 - (1 + k^{'}) c^{' 2} h^{2}}} + \underset{j}{Σ} {A_{j}^{'} h}^{2 j},

It is for describing the formula of taper and aspheric surface.Here, h ²=x ' ²+ y ' ², and A ' _jIt is the coefficient that characterizes rotation symmetric reference surface stray circle poppet surface.Usually, the non-spherical coefficient A ' that is used for the reference surface of match mirror surface _jNumber change according to the computing power of system of the precision level that is used for gauging surface, pot life and hope.In certain embodiments, reference surface can use the non-spherical coefficient calculations that reaches three rank.In a particular embodiment, use the coefficient (for example, quadravalence, six rank) that is higher than three rank.For taper and the parameterized more discussion of aspheric surface, for example, can be with reference to the CodeV product manual, its can obtain from Optical Research Associates (Pasadena, CA)

Usually, can use different optimized Algorithm to carry out match.For example, in certain embodiments, can use the least square fitting algorithm, for example the damped least squares fitting algorithm.The damped least squares fitting algorithm can use and can the commercial optical design software that obtains calculate, for example Code V or ZEMAX (can be from Optima Research, Ltd., Standsted, United Kingdom acquisition).

After having defined rotation symmetric reference surface, can determine and visual local distance between other points of minute surface.Also can determine to rotate other features of symmetric reference surface.For example, can determine to rotate the symmetric reference surface and depart from the maximal value of rotating asymmetric minute surface.

For example, the free type surface can have more than or equal to about λ from the maximum deviation on best-fit sphere or rotation symmetric reference surface (for example, more than or equal to about 10 λ, more than or equal to about 20 λ, more than or equal to about 50 λ, more than or equal to about 100 λ, more than or equal to about 150 λ, more than or equal to about 200 λ, more than or equal to about 500 λ, more than or equal to about 1000 λ, more than or equal to about 10000 λ, more than or equal to about 50000 λ).The free type surface more than or equal to the maximum deviation of rotating asymmetric sphere from best-fit of about λ (for example can have, more than or equal to about 5 λ, more than or equal to about 10, more than or equal to about 20 λ, more than or equal to about 50 λ, more than or equal to about 100, more than or equal to about 200, more than or equal to about 500, more than or equal to about 1000 λ, more than or equal to about 10000).In certain embodiments, the free type surface can have the maximum deviation from best-fit rotation symmetroid that is less than or equal to about 1000 λ and (for example, is less than or equal to about 900, be less than or equal to about 800, be less than or equal to approximately 700, be less than or equal to about 600 λ, be less than or equal to about 500).

In a particular embodiment, the free type surface can have more than or equal to 10nm from the maximum deviation of best-fit sphere (for example, more than or equal to about 100nm, more than or equal to about 500nm, more than or equal to about 1 μ m, more than or equal to about 5 μ m, more than or equal to about 10 μ m, more than or equal to about 50 μ m, more than or equal to about 100 μ m, more than or equal to about 200 μ m, more than or equal to about 500 μ m, more than or equal to about 1000 μ m, more than or equal to about 2000 μ m, more than or equal to about 3000 μ m).The free type surface can have the maximum deviation from the best-fit sphere (for example, be less than or equal to about 5mm, be less than or equal to about 3mm, be less than or equal to about 2mm, be less than or equal to about 1mm, be less than or equal to about 500 μ m) that is less than or equal to about 10mm.

The free type surface can have and (for example rotates symmetrical aspheric maximum deviation more than or equal to about 10nm from best-fit, more than or equal to about 100nm, more than or equal to about 500nm, more than or equal to about 1 μ m, more than or equal to about 5 μ m, more than or equal to about 10 μ m, more than or equal to about 50 μ m, more than or equal to about 100 μ m, more than or equal to about 200 μ m, more than or equal to about 500 μ m, about 1000 μ m).The free type surface can have be less than or equal to about 10mm (for example rotate symmetrical aspheric maximum deviation from best-fit, be less than or equal to about 5mm, be less than or equal to about 3mm, be less than or equal to about 2mm, be less than or equal to about 1mm, be less than or equal to about 500 μ m).

The curvature of minute surface characterizes with the first and second average principal curvaturess, and they are determined by the point on each minute surface of the chief ray of reflection kernel field point.The first and second average principal curvaturess can be as Handbook ofMathematics by I.N.Bronstein, et al., 4 ^ThEd. (Springer, 2004), p567, calculate with describing.Usually, first principal curvatures of catoptron is different from second principal curvatures of catoptron.In certain embodiments, the absolute value of the difference between first and second principal curvaturess is more than or equal to about 10 ^-8(for example, more than or equal to 10 ^-7, more than or equal to 5 * 10 ^-7, more than or equal to about 10 ^-6, more than or equal to about 5 * 10 ^-6, more than or equal to about 10 ^-5, more than or equal to about 5 * 10 ^-5, more than or equal to about 10 ^-4, more than or equal to about 5 * 10 ^-4, more than or equal to about 10 ^-3).

Usually, first and/or second principal curvatures can be for positive or for negative.First and/or second principal curvatures of minute surface can be less relatively.For example, in certain embodiments, for the one or more catoptrons in projection objective 101, the absolute value of first principal curvatures is to be less than or equal to about 10 ^-2(for example, be less than or equal to about 5 * 10 ^-3, be less than or equal to about 3 * 10 ^-3, be less than or equal to about 2 * 10 ^-3, be less than or equal to about 10 ^-3).The absolute value of the first principal curvatures sum of catoptron can be less than or equal to about 10 in projection objective 101 ^-3(for example, be less than or equal to about 5 * 10 ^-4, be less than or equal to about 3 * 10 ^-4, be less than or equal to about 2 * 10 ^-4, be less than or equal to about 10 ^-4, be less than or equal to 5 * 10 ^-5, be less than or equal to 10 ^-5).

In a particular embodiment, for the one or more catoptrons in projection objective 101, the absolute value of second principal curvatures is to be less than or equal to about 10 ^-2(for example, be less than or equal to about 5 * 10 ^-3, be less than or equal to about 3 * 10 ^-3, be less than or equal to about 2 * 10 ^-3, be less than or equal to about 10 ^-3).The absolute value of the second principal curvatures sum of catoptron can be to be less than or equal to about 10 in projection objective 101 ^-3(for example, be less than or equal to about 5 * 10 ^-4, be less than or equal to about 3 * 10 ^-4, be less than or equal to about 2 * 10 ^-4, be less than or equal to about 10 ^-4, be less than or equal to 5 * 10 ^-5, be less than or equal to 10 ^-5).

The first and second principal curvatures sums of catoptron in projection objective 101, promptly, the first principal curvatures sum of all catoptrons in the projection objective 101, the second principal curvatures sum of all catoptrons in the projection objective 101, or the first and second principal curvatures sums of all catoptrons in the projection objective 101, can be less.For example, the absolute value of the first and second principal curvatures sums of catoptron can be less than or equal to about 10 ^-3(for example, be less than or equal to about 5 * 10 ^-4, about 3 * 10 ^-4, be less than or equal to about 2 * 10 ^-4, be less than or equal to about 10 ^-4, be less than or equal to 5 * 10 ^-5, be less than or equal to 10 ^-5).

In a particular embodiment, the free type minute surface can be described with formula mathematics ground:

Z = \frac{{cr}^{2}}{1 + \sqrt{1 - (1 + k) c^{2} r^{2}}} + Σ_{j = 2}^{66} C_{j} X^{m} Y^{n}

Wherein

j = \frac{{(m + n)}^{2} + m + 3 n}{2} + 1

And Z is the sag that is parallel to the surface of Z axle (it can be parallel or be not parallel to the Z axle in projection objective 101, that is, it is eccentric and favours the Z axle in projection objective 101 usually), and c is the constant corresponding to vertex curvature, and k is the cone constant, and C _jBe monomial X _mY _nCoefficient.Usually, c, k and C _jHope optical characteristics according to the catoptron relevant with projection objective 101 is determined.And, the exponent number of monomial, m+n can change on demand.Usually, the monomial of higher-order can provide the design of the projection objective with higher aberration correction level, yet the common more computation of the monomial of higher-order becomes original and determines.In certain embodiments, m+n is more than or equal to 10 (for example, more than or equal to 15, more than or equal to 20).As described below, the parameter of free type catoptron formula can be used and can the commercial optical design software that obtains determine.In certain embodiments, m+n is less than 10 (for example, are less than or equal to 9, are less than or equal to 8, be less than or equal to 7, be less than or equal to 6, be less than or equal to 5, be less than or equal to 4, be less than or equal to 3).

Usually, except shown in top, the formula mathematical description can be used in the free type surface.For example, in certain embodiments, the free type surface can use Zernike polynomial expression mathematics to describe (for example at handbook CODE

The middle appearance, it can be from Optical Research Associates, Pasadena, and CA is commercial to be obtained.) or use two-dimentional spline surface.The example of two-dimensional spline curved surface is Bezier batten or non-uniform rational Bezier batten (NURBS).For example, the two-dimensional spline curved surface can be put with the net point on the x-y plane and corresponding z value or slope and these and describe.According to the particular type of spline surface, obtain whole curved surfaces by for example utilizing polynomial expression or function interpolation between net point, described polynomial expression or function have the characteristic relevant with continuity or differentiability (for example analytical function).

Usually, the number of the free type catoptron in projection objective 101 and position can change.Embodiment can comprise more than or equal to the projection objective of two free type catoptrons (for example having, more than or equal to three free type catoptrons, more than or equal to four free type catoptrons, more than or equal to five free type catoptrons, more than or equal to six free type catoptrons).

Projection objective 101 generally includes one or more catoptron with positive light coke.That is to say that the reflecting part of catoptron has concave surface, is known as concave mirror.Projection objective 101 can comprise the concave mirror (for example, more than or equal to three, more than or equal to four, more than or equal to five, more than or equal to six) more than or equal to two.Projection objective 101 can also comprise the catoptron with negative power.One or more catoptron has the reflecting part (being called convex mirror) of convex surface in other words.In certain embodiments, projection objective 101 can comprise the convex mirror (for example, more than or equal to three, more than or equal to four, more than or equal to five, more than or equal to six) more than or equal to two.

Figure 3 illustrates the embodiment of the projection objective that comprises six catoptrons.Especially, projection objective 300 comprises six free type catoptrons 310,320,330,340,350 and 360.Shown in the data of projection objective 300 table 1A below and the table 1B.Table 1A shows optical data, and table 1B shows the free type constant of each minute surface.In order to show the purpose of 1A and table 1B, the following correspondence of catoptron title: the corresponding catoptron 310 of catoptron 1 (M1); The corresponding catoptron 320 of catoptron 2 (M2); The corresponding catoptron 330 of catoptron 3 (M3); The corresponding catoptron 340 of catoptron 4 (M4); The corresponding catoptron 350 of catoptron 5 (M5); The corresponding catoptron 360 of catoptron 6 (M6).Table 1A and show subsequently in " thickness " refer to the distance of adjacent elements in the light path.For the free type catoptron, monomial coefficient C _jEccentric and the rotation (perhaps tilting) of this catoptron quilt from initial projection objective design is provided in table 1B with number of mirrors.Radius R is the inverse of vertex curvature c.Off-centre represents that with mm rotation expenditure numerical table shows.The dimension of monomial coefficient is mm ^=j+1The N radius is a nondimensional scalar factor (for example, can read handbook CODE V).

In Fig. 3, projection objective 300 illustrates in the meridian cross section.Meridian ellipse is the plane of symmetry of projection objective 300.The symmetry of meridian ellipse is meant relatively, and the only relative y eccentric shaft of catoptron tilts with relative x axle.And, on the x coordinate axis, have odd-order (for example, x, x ³, x ⁵, etc.) the coefficient of free type catoptron be zero.

Projection objective 300 is configured to work under 13.5nm illumination, and has 0.35 picture side NA and 1500mm track lenth.The optical path length of imaging is 3833mm.Thereby the ratio of optical path length and track lenth approximately is 2.56.Projection objective has the minification of 4X, less than the maximum distortion of 100nm, the W of 0.035 λ _RmsThe curvature of field with 28nm.Other features of projection objective 300 are occurring in the discussion to projection objective 101 subsequently.

For example, from first catoptron in the light path of object plane 103, promptly catoptron 310, have positive light coke.Catoptron 320,340 and 360 also is the

P catoptron.Catoptron

330 and 350 has negative (N) focal power.Therefore, the catoptron in the light path of projection objective 300 is PPNPNP in proper order.

Table 1A

Table 1B

For the catoptron in the projection objective 300, the free type curved surface is as follows from the maximum deviation of the best-fit sphere of each catoptron: for catoptron 310 are 154 μ m; For catoptron 320 are 43 μ m; For catoptron 330 are 240 μ m; For catoptron 340 are 1110 μ m; For catoptron 350 are 440 μ m; For catoptron 360 are 712 μ m.The free type curved surface rotates symmetrical aspheric maximum deviation from best-fit: for catoptron 310 is 47 μ m; For catoptron 320 is 33 μ m; For catoptron 330 is 96 μ m; For catoptron 340 is 35 μ m; For catoptron 350 is 152 μ m; For catoptron 360 is 180 μ m;

First and second principal curvaturess of catoptron 310 are respectively 9.51 * 10 ^-4With 9.30 * 10 ^-4First and second principal curvaturess of other catoptrons are as follows respectively in the projection objective 300: catoptron 320 is 2.76 * 10 ^-5With 1.56 * 10 ^-5 Catoptron 330 is-2.38 * 10 ^-3With-2.17 * 10 ^-3 Catoptron 340 is 1.79 * 10 ^-3With 1.75 * 10 ^-3 Catoptron 350 is-2.64 * 10 ^-3With-2.10 * 10 ^-3 Catoptron 360 is 1.93 * 10 ^-3With 1.91 * 10 ^-3The first principal curvatures sum of projection objective 300 is-3.19 * 10 ^-4The second principal curvatures sum is 3.29 * 10 ^-4The first and second principal curvatures sums are 9.97 * 10 ^-6, and the inverse of the first and second principal curvatures sums is 1.00 * 10 ^-5

In a particular embodiment, the feasible photoimaging from object plane 103 of the placement of catoptron arrives one or more intermediate image plane in the projection objective 101.For example, projection objective 300 will be from the photoimaging of object plane 103 to the intermediary image that is near the position 305 the catoptron 360.Embodiment with one or more intermediary image also comprises the pupil plane more than or equal to two.In certain embodiments, in order to place aperture diaphragm basically on the pupil plane, at least one is that physics can contact in these pupil planes.Aperture diaphragm is used to limit the size in the aperture of projection objective.

In projection objective 101, the coma on the intermediary image may be bigger.Coma can by chief ray and up and down the distance between the light up and down at cross-over place quantize.In certain embodiments, this distance can be more than or equal to about 1mm (for example, more than or equal to about 2mm, more than or equal to about 3mm, more than or equal to about 4mm, more than or equal to about 5mm, more than or equal to about 6mm, more than or equal to about 7mm).In projection objective, the coma on the intermediary image can be less.In certain embodiments, this distance can be to be less than or equal to about 1mm (for example, be less than or equal to about 0.1mm, be less than or equal to about 0.01mm).

Usually, the catoptron of projection objective is formed, and makes that its reflection major part impinges perpendicularly on it or the wavelength that incides on it in certain specific incident angle scope is the light of λ.For example, catoptron can be formed from into, make its reflection more than or equal to about 50% (for example, more than or equal to about 60%, more than or equal to about 70%, more than or equal to about 80%, more than or equal to about 90%, more than or equal to about 95%, more than or equal to about 98%) the vertical incidence light of wavelength X.

In certain embodiments, catoptron comprises the film lamination of multiple layers of different materials, and it is set to the vertical incidence light of reflected wavelength lambda basically.Every tunic in the lamination can have the optical thickness of about λ/4.Multilayer laminated comprise more than or equal to about 20 (for example, more than or equal to about 30, more than or equal to about 40, more than or equal to about 50) film.Usually, being used to constitute multilayer laminated material can select according to operation wavelength λ.For example, molybdenum that multilayer replaces and silicon or molybdenum and beryllium film can be used to be configured for to reflect the reflection of light mirror (for example, λ approximately be respectively 13nm, perhaps 11nm) of 10nm in the 30nm scope.Usually, molybdenum and silicon fiml that multilayer replaces are preferred for λ=11nm, and molybdenum beryllium and film that multilayer replaces are preferred for λ=13nm.

In a particular embodiment, catoptron is formed by such quartz glass, the aluminium of its coated individual layer, and applies one or more layers dielectric material again, for example by MgF ₂, LaF ₂Or Al ₂O ₃The layer that forms.For example, can use the catoptron that forms by aluminium to be used to have the light of about 193nm wavelength with dielectric coated.

Usually, the be reflected wavelength of mirror reflection is that the percent of the light of λ changes according to minute surface glazed thread incident angle.Because imaging passes the reflective projection object lens and propagates along a plurality of different paths, so the incident angle of each catoptron glazing can change.This effect illustrates with reference to figure 4, wherein shows the part of the catoptron 400 on the meridian cross section, and it comprises concave reflection surface 401.Imaging is along the incident on surface 401 of a plurality of different paths, and described path comprises by the path shown in light 410,420 and 430.Light 410,420 and 430 incident, wherein surface normal difference on the part on surface 401.The direction of the surface normal of these parts is illustrated by line 411,421 and 431, corresponds respectively to light 410,420 and 430.Light 410,420 and 430 is respectively with angle θ ₄₁₀, θ ₄₂₀And θ ₄₃₀Incide on the surface 401.Usually, angle θ ₄₁₀, θ ₄₂₀And θ ₄₃₀Variable.

For each catoptron in the projection objective 101, the incident angle of imaging can characterize with different modes.A kind of sign is the maximum incident angle degree that incides the meridional ray on each catoptron on the meridian cross section of projection objective 101.Meridional ray is meant the light that is arranged in the meridian cross section.Usually, in projection objective 101 for different catoptron θ _MaxVariable.

In certain embodiments, the maximum θ of all catoptrons in the projection objective 101 _MaxValue is to be less than or equal to about 75 ° (for example, are less than or equal to about 70 °, are less than or equal to about 65 °, be less than or equal to about 60 °, be less than or equal to about 55 °, be less than or equal to about 50 °, be less than or equal to about 45 °).θ _MaxCan be greater than about 5 ° (for example, more than or equal to about 10 °, more than or equal to about 20 °).In certain embodiments, maximum θ _MaxValue can be less.For example, maximum θ _MaxValue can be to be less than or equal to 40 ° (for example, are less than or equal to about 35 °, are less than or equal to about 30 °, be less than or equal to about 25 °, be less than or equal to about 20 °, be less than or equal to about 15 °, be less than or equal to about 13 °, be less than or equal to about 10 °).

As an example, in projection objective 300, the θ of catoptron 310 _MaxBe 8.22 °, the θ of catoptron 320 _MaxBe 10.38 °, the θ of catoptron 330 _MaxBe 22.35 °, the θ of catoptron 340 _MaxBe 7.49 °, the θ of catoptron 350 _MaxBe 24.58 °, the θ of catoptron 360 _MaxIt is 6.15 °.

In certain embodiments, θ _MaxMaximal value (angle) with can be to be less than or equal to about 100 (for example, be less than or equal to approximately 80, be less than or equal to about 70 as the ratio of side NA, be less than or equal to approximately 68, be less than or equal to approximately 60, be less than or equal to about 50, be less than or equal to approximately 40, be less than or equal to about 30).

The another kind of sign is the chief ray incident angle that put the central authorities field corresponding on each catoptron in the meridian cross section of projection objective 101.This angle is called θ _CRUsually, θ _CRVariable.For example, for projection objective 300, catoptron 310 has 6.59 ° θ _CR, catoptron 320 has 7.93 ° θ _CR, catoptron 330 has 20.00 ° θ _CR, catoptron 340 has 7.13 ° θ _CR, catoptron 350 has 13.06 ° θ _CR, catoptron 360 has 5.02 ° θ _CRIn certain embodiments, in projection objective 101, θ _CRMaximal value, θ _CR(max) can be lower.For example, θ _CR(max) can be to be less than or equal to about 35 ° (for example, to be less than or equal to about 30 °, to be less than or equal to about 25 °, be less than or equal to about 20 °, be less than or equal to about 15 °, be less than or equal to about 13 °, be less than or equal to about 10 °, be less than or equal to about 8 °, be less than or equal to about 5 °).For projection objective 300, θ _CR(max) be 20.00 °, it is the θ of catoptron 330 _CR

In certain embodiments, θ _{CR (max)}Maximal value (angle) with can be to be less than or equal to about 100 (for example, be less than or equal to approximately 80, be less than or equal to about 70 as the ratio of side NA, be less than or equal to approximately 68, be less than or equal to approximately 60, be less than or equal to about 50, be less than or equal to approximately 40, be less than or equal to about 30).

Each catoptron in the projection objective 101 also can be characterized by the incident angle range delta θ of projection objective 101 meridian ellipse glazed threads.For each catoptron, Δ θ is corresponding to θ _MaxWith θ _MinBetween difference, θ wherein _MinIt is the minimum angles of the light of each catoptron of incident on projection objective 101 meridian ellipses.Usually, Δ θ is variable for each catoptron in the projection objective 101.For some catoptrons, Δ θ can be less, for example, Δ θ is less than or equal to about 20 ° (for example, to be less than or equal to about 15 °, be less than or equal to about 12 °, be less than or equal to about 10 °, be less than or equal to about 8 °, be less than or equal to about 5 °, be less than or equal to about 3 °, be less than or equal to 2 °).Be that for some catoptrons in the projection objective 101, Δ θ can be bigger alternatively.For example, the Δ θ of some catoptrons can be more than or equal to 20 ° (for example, more than or equal to about 25 °, more than or equal to about 30 °, more than or equal to about 35 °, more than or equal to about 40 °).For projection objective 300, the Δ θ of catoptron 310 _MaxBe 3.34 °, the Δ θ of catoptron 320 _MaxBe 4.92 °, the Δ θ of catoptron 330 _MaxBe 5.18 °, the Δ θ of catoptron 340 _MaxBe 0.98 °, the Δ θ of catoptron 350 _MaxBe the Δ θ of 24.07 ° and catoptron 360 _MaxIt is 2.77 °.

In certain embodiments, the Δ θ maximal value of all catoptrons in the projection objective 101, Δ θ _Max, can be less.For example, Δ θ _MaxCan be less than or equal to about 25 ° (for example, be less than or equal to about 20 °, be less than or equal to about 15 °, be less than or equal to about 12 °, be less than or equal to about 10 °, be less than or equal to about 9 °, be less than or equal to about 8 °, be less than or equal to about 7 °, be less than or equal to about 6 °, be less than or equal to about 5 °, be less than or equal to about 3 °).For projection objective 300, Δ θ _MaxIt is 24.07 °

The another kind of mode that characterizes light path in the projection objective 101 is by the chief ray magnification on each catoptron, just refers to before each mirror reflects and afterwards the merchant of angle tangent between chief ray (for example, in the meridian cross section) and axis of reference 105.For example, with reference to figure 5A, wherein before catoptron 510 reflections, chief ray 501 departs from from axis of reference 105, and from catoptron 510 reflected back axis of reference 105, catoptron 510 has positive chief ray angle magnification.With reference to figure 5B, alternatively, wherein before catoptron 520 reflection and afterwards, chief ray 502 all departs from axis of reference 105, and catoptron 520 has negative chief ray angle magnification.In both cases, the chief ray magnification is provided by tan (α)/tan (β).In a particular embodiment, in projection objective, a plurality of have the catoptron of positive chief ray angle magnification corresponding to incident angle bigger on one or more catoptron.Therefore, only have the projection objective with catoptron of positive chief ray angle magnification also can show less incident angle of light on catoptron.For projection objective 300, catoptron 310,320,330 and 350 has negative chief ray angle magnification, and catoptron 340 has positive chief ray angle magnification.

Relative spacing in the projection objective 101 between catoptron is variable according to the specific design of projection objective.Less incident angle of light on distance bigger between the adjacent mirror (with respect to light path) can be corresponding to catoptron.In a particular embodiment, projection objective 101 can comprise that at least one pair of separates the adjacent mirror greater than 50% projection objective track lenth.For example, in projection objective 300,

catoptron

340 and 350 is at a distance of greater than 50% projection objective track lenth.

In a particular embodiment, and between second catoptron in object plane and the light path apart from d _Op-2Compare, have bigger relative distance d between first catoptron in object plane and light path _Op-1,, this embodiment can be corresponding to incident angle of light lower on the catoptron.For example, d _Op-1/ d _Op-2(for example, more than or equal to about 2.5, more than or equal to about 3, more than or equal to about 3.5, more than or equal to about 4, more than or equal to about 4.5, more than or equal to about 5) embodiment also can have lower incident angle of light more than or equal to about 2.In projection objective 300, d _Op-1/ d _Op-2Be 2.38.

Usually, the occupy-place face size in projection objective 101 and the shape variable of catoptron.Occupy-place face shape digital reflex mirror projects to the shape on the x-y plane.The occupy-place face of catoptron can be circular, oval, polygon (for example, rectangle, square, hexagon) or irregularly shaped.In an embodiment, occupy-place face is with respect to the meridian ellipse symmetry of projection objective 101.

In a particular embodiment, the full-size of the occupy-place face that catoptron can have is for (for example being less than or equal to about 1500mm, be less than or equal to about 1400mm, be less than or equal to about 1300mm, be less than or equal to about 1200mm, be less than or equal to about 1100mm, be less than or equal to about 1000mm, be less than or equal to about 900mm, be less than or equal to about 800mm, be less than or equal to about 700mm, be less than or equal to about 600mm, be less than or equal to about 500mm, be less than or equal to about 400mm, be less than or equal to about 300mm, be less than or equal to about 200mm, be less than or equal to about 100mm).The full-size of the occupy-place face that catoptron can have is more than or equal to about 10mm (for example, more than or equal to about 20mm, more than or equal to about 50mm).

Example at the catoptron 600 that has oval occupy-place face shown in Fig. 6 A.Catoptron 600 has the full-size of x direction, and it is by M _xExpression.In an embodiment, M _xCan be to be less than or equal to about 1500mm (for example, to be less than or equal to about 1400mm, to be less than or equal to about 1300mm, be less than or equal to about 1200mm, be less than or equal to about 1100mm, be less than or equal to about 1000mm, be less than or equal to about 900mm, be less than or equal to about 800mm, be less than or equal to about 700mm, be less than or equal to about 600mm, be less than or equal to about 500mm, be less than or equal to about 400mm, be less than or equal to about 300mm, be less than or equal to about 200mm, be less than or equal to about 100mm).M _xCan be greater than about 10mm (for example, more than or equal to about 20mm, more than or equal to about 50mm).

Catoptron 600 is with respect to meridian 601 symmetries.Catoptron 600 has size M along meridian 601 _yFor catoptron 600, M _yCompare M _xLittle, yet, more generally, M _yCan be less than, be equal to, or greater than M _xIn certain embodiments, M _yScope be 0.1M _xTo M _x(for example, more than or equal to about 0.2M _x, more than or equal to about 0.3M _x, more than or equal to about 0.4M _x, more than or equal to about 0.5M _x, more than or equal to about 0.6M _x, more than or equal to about 0.7M _x, more than or equal to about 0.8M _x, more than or equal to about 0.9M _x).Be alternatively, in a particular embodiment, M _yCan be more than or equal to about 1.1M _x(for example, more than or equal to about 1.5M _x), for example from about 2M _xTo 10M _xScope in.M _yCan be (for example to be less than or equal to about 1000mm, be less than or equal to about 900mm, be less than or equal to about 800mm, be less than or equal to about 700mm, be less than or equal to about 600mm, be less than or equal to about 500mm, be less than or equal to about 400mm, be less than or equal to about 300mm, be less than or equal to about 200mm, be less than or equal to about 100mm).M _yCan be greater than about 10mm (for example, more than or equal to about 20mm, more than or equal to about 50mm).

In projection objective 300, the M of catoptron 310 _xAnd M _yBe respectively 303mm and 139mm; The M of catoptron 320 _xAnd M _yBe respectively 187mm and 105mm; The M of catoptron 330 _xAnd M _yBe respectively 114mm and 62mm; The M of catoptron 340 _xAnd M _yBe respectively 299mm and 118mm; The M of catoptron 350 _xAnd M _yBe respectively 99mm and 71mm; The M of catoptron 360 _xAnd M _yBe respectively 358mm and 332mm;

In certain embodiments, the pedestal of catoptron can extend to (for example, the part of the optical reflection imaging of catoptron) outside the minute surface in one or more direction.For example, the pedestal of catoptron can extend beyond the optics effective surface more than or equal to about 10mm (for example, more than or equal to about 20mm, more than or equal to about 30mm, more than or equal to about 40mm, more than or equal to about 50mm) at x and/or y direction.By the non-optical effective surface that can be attached to erecting device is provided, Reflector base is extended with and is beneficial to connection catoptron is installed in the projection objective 101.

Preferably, the Reflector base extension should be on the direction of the light path in blocking projection objective 101.When light when the catoptron, distance between catoptron edge and the light path and the relating to parameters that is called " freeboard ", this parameter be near the light at catoptron edge and the mirror reflection that is reflected near the minor increment between the light at catoptron edge.In certain embodiments, projection objective 101 can comprise more than or equal to about 20mm (for example having, more than or equal to about 25mm, more than or equal to about 30mm, more than or equal to about 35mm, more than or equal to about 40mm, more than or equal to about 45mm, more than or equal to about 50mm) one or more catoptron of freeboard.Big freeboard provides the dirigibility in catoptron processing, because projection objective can hold the Reflector base of extension, and does not stop imaging.Yet in projection objective, less freeboard is corresponding to incident angle of light little on the catoptron.In certain embodiments, projection objective 101 can comprise one or more catoptron with the freeboard that is less than or equal to about 15mm (for example, be less than or equal to about 12mm, be less than or equal to about 10mm, be less than or equal to about 8mm, be less than or equal to about 5mm).In a particular embodiment, projection objective 101 comprises that one or more has one or more catoptrons of the freeboard between 5 to 25mm.For example, in projection objective 300, the freeboard that catoptron 310,320,330,350 and 360 has between 5 to 25mm.

Usually, the variable thickness of catoptron in the projection objective 101.The thickness digital reflex mirror normal of catoptron is to the size of its optical surface.Usually, catoptron should have sufficient thickness so that fit in the projection objective.With reference to figure 6B, the thickness of catoptron 600 can be used maximum ga(u)ge T _MaxWith minimum thickness T _MinDescribe.Usually, T _MaxAnd T _MinBetween difference depend on the structure of curvature mirror and Reflector base.In certain embodiments, T _MaxBeing less than or equal to about 200mm (for example, is less than or equal to about 150mm, is less than or equal to about 100mm, be less than or equal to about 80mm, be less than or equal to about 60mm, be less than or equal to about 50mm, be less than or equal to about 40mm, be less than or equal to about 30mm, be less than or equal to about 20mm).In a particular embodiment, T _MinMore than or equal to about 1mm (for example, more than or equal to about 2mm, more than or equal to about 5mm, more than or equal to about 10mm, more than or equal to about 20mm, more than or equal to about 50mm, more than or equal to about 100mm).

In certain embodiments, the full-size of any catoptron is to be less than or equal to about 1500mm (for example, to be less than or equal to about 1400mm in the projection objective, be less than or equal to about 1300mm, be less than or equal to about 1200mm, be less than or equal to about 1100mm, be less than or equal to about 1000mm, be less than or equal to about 900mm, be less than or equal to about 800mm, be less than or equal to about 700mm, be less than or equal to about 600mm, be less than or equal to about 500mm, be less than or equal to about 300mm).In certain embodiments, the full-size of any catoptron is (for example, more than or equal to about 20mm more than or equal to about 10mm in the projection objective, more than or equal to about 30mm, more than or equal to about 40mm, more than or equal to about 50mm, more than or equal to about 75mm, more than or equal to about 100mm).

Usually, the field shape variable of projection objective 101.In certain embodiments, the field has arcuate shape, for example the shape of ring section.With reference to figure 7A, ring section field 700 can be by the d of x dimension _x, the y dimension d _yWith radius dimension d _rCharacterize.d _xAnd d _yCorrespond respectively to along the size of the field of x direction and y direction.d _rCorresponding to the ring radius, its from axle 705 to the field 700 inner boundary measure and obtain.Encircle section field 700 with respect to the plane symmetry that is parallel to the y-z plane, and by line 710 expressions.Usually, d _x, d _y, and d _rSize according to the design variation of projection objective 101.Usually, d _yCompare d _x Little.Object plane 103 with the picture plane 102 on relevant field dimension d _x, d _y, and d _rSize change according to the magnification of projection objective 101 or minification.

In certain embodiments, the d on picture plane 102 _xBigger.For example, the d on picture plane 102 _xCan be more than or equal to 1mm (for example, more than or equal to about 3mm, more than or equal to about 4mm, more than or equal to about 5mm, more than or equal to about 6mm, more than or equal to about 7mm, more than or equal to about 8mm, more than or equal to about 9mm, more than or equal to about 10mm, more than or equal to about 11mm, more than or equal to about 12mm, more than or equal to about 13mm, more than or equal to about 14mm, more than or equal to about 15mm, more than or equal to about 18mm, more than or equal to about 20mm, more than or equal to about 25mm).d _xCan be to be less than or equal to about 100mm (for example, be less than or equal to about 50mm, be less than or equal to about 30mm).D on the picture plane 102 _yCan be at about 0.5mm (for example, about 1mm, about 2mm, about 3mm, about 4mm) in the scope between about 5mm.

Usually, as the d on the plane 102 _rMore than or equal to about 10mm.For example, as the d on the plane 102 _rCan be more than or equal to about 15mm (for example, more than or equal to about 20mm, more than or equal to about 25mm, more than or equal to about 30mm).In certain embodiments, d _rCan be very big (for example, more than or equal to about 1m, more than or equal to about 5m, more than or equal to about 10m).In a particular embodiment, the field is a rectangular shape, d _rBe infinitely great.For example, projection objective 300 has rectangular field.In particular, in the picture plane surveying, projection objective 300 has in the y dimension and is 2mm and is the rectangular field of 26mm in the x dimension.

More generally, for other shapes, projection objective 101 can have maximum field size greater than 1mm on as plane 102 (for example, more than or equal to about 3mm, more than or equal to about 4mm, more than or equal to about 5mm, more than or equal to about 6mm, more than or equal to about 7mm, more than or equal to about 8mm, more than or equal to about 9mm, more than or equal to about 10mm, more than or equal to about 11mm, more than or equal to about 12mm, more than or equal to about 13mm, more than or equal to about 14mm, more than or equal to about 15mm, more than or equal to about 18mm, more than or equal to about 20mm, more than or equal to about 25mm).In a particular embodiment, projection objective has the maximum field size (for example, be less than or equal to about 50mm, be less than or equal to about 30mm) that is no more than about 100mm.

In certain embodiments, the image field shape is corresponding to the shape of wafer position on (for example in one or more dimensions) wafer, and described wafer utilizes projection objective 101 exposures.For example, when exposed wafer, image field is shaped as the reduction overscanning.Overscanning refers to that needs surpass the boundary scan image field of wafer position with the whole position of exposing.Usually, this occurs under the shape and the inconsistent situation of wafer position shape of image field.

Overscanning can be characterized (for example, being expressed as number percent) by the ratio of the ultimate range between aberration leading edge and wafer position back edge, and at described wafer position, the corner that is in its rear rim is exposed.With reference to figure 7B, overscanning is corresponding to d _OsWith d _yRatio, d wherein _OsBe the distance between image field 700 leading edges and wafer position 720 back edge, be exposed in the

back edge corner

721 and 722 of described wafer position.In a particular embodiment, projection objective can have less overscanning.For example, projection objective can have and is less than or equal to about 5% overscanning (for example, be less than or equal to approximately 4%, be less than or equal to approximately 3%, be less than or equal to approximately 2%, be less than or equal to approximately 1%, be less than or equal to approximately 0.5%, be less than or equal to about 0.1%).

In a particular embodiment, the projection objective 101 of use can have zero overscanning.For example, with reference to figure 7C, under the embodiment that uses the square wafer position 740 of image field 730 exposures, can scan with zero overscanning.

With reference to figure 8, usually, projection objective 101 is introduced the image offset d _Ois, its specific design according to projection objective changes.Image skew is meant the distance of the respective point of point in the thing field in the image field, and it is measured in the x-y plane.For the projection objective with optical axis (public rotation axes of symmetry of each catoptron in the projection objective), the image skew can use following formula to calculate:

d _ois＝h _o(1-M)

H wherein _oRefer to the distance on the x-y plane of central field point on the thing field, and M is the magnification of projection objective apart from optical axis.For example, for have the 4X minification (for example, M=0.25) and central field point apart from optical axis the projection objective of 120mm, d are arranged _OisBe 90mm.

In certain embodiments, projection objective 101 can have less image skew, and for example, projection objective has zero image skew.Projection objective with less image skew can have more elongated optical design.And, in embodiment with the skew of zero image, projection objective 101 can along with thing field and image field on the axle that intersects of central field point rotate, and do not need the central field point with respect to for example objective table 130 translations.For example, when being used for respect to projection objective 101 detections in the placement of the normal position of central field point and aiming at the metering outfit of wafer, this is favourable, because when projection objective rotates, central field point does not have translation in this position relatively.Thereby in operating process, in projection objective when rotation,, zero image skew makes the metering of projection objective 101 and test convenient more.This is shown in Figure 8, and it shows test and metering outfit 150a in picture plane 150, and its test surfaces for example is the ccd array of two dimension.This test is placed with metering outfit so that axis of reference consistent with axle 150 and detection faces central point intersect.The horizontal expansion of the detection faces of test and metering outfit 150a is greater than the image offset d _OisBecause less image offset d _Ois, the projection quality of test and metering outfit 150a energy measurement projection objective 101, and need not to consider the rotation of projection objective 101 around axis of reference 105.

In certain embodiments, projection objective 101 has the d that is less than or equal to about 80mm _Ois(for example, be less than or equal to about 60mm, be less than or equal to about 50mm, be less than or equal to about 40mm, be less than or equal to about 30mm, be less than or equal to about 20mm, be less than or equal to about 15mm, be less than or equal to about 12mm, be less than or equal to about 10mm, be less than or equal to about 8mm, be less than or equal to about 5mm, be less than or equal to about 4mm, be less than or equal to about 3mm, be less than or equal to about 2mm, be less than or equal to about 1mm).For example, projection objective 300 has the d of 57mm _Ois

The embodiment of projection objective 101 can have the bigger free operating distance of picture side.Refer to bee-line between the minute surface of the catoptron of picture plane 102 and the most contiguous optical reflection imaging as plane 102 as the free operating distance of side.The definition of this free operating distance is different from the definition in the optical system that has the rotation symmetrical surface usually, and wherein, free operating distance is normally measured in optical axis.According to the application, shown in Figure 9 corresponding to the free operating distance of definition, wherein show the nearest catoptron on distance images plane 102, catoptron 810.Light is from surface 811 reflections of catoptron 810.Be labeled as d as the free operating distance of side _wIn certain embodiments, d _wMore than or equal to about 25mm (for example, more than or equal to about 30mm, more than or equal to about 35mm, more than or equal to about 40mm, more than or equal to about 45mm, more than or equal to about 50mm, more than or equal to about 55mm, more than or equal to about 60mm, more than or equal to about 65mm).In a particular embodiment, d _wBe approximately to be less than or equal to 200mm (for example, be less than or equal to about 150mm, be less than or equal to about 100mm, be less than or equal to about 50mm).For example, projection objective 300 has the free operating distance of picture side of about 45mm.Bigger also wishes as the side operating distance, because it allows the surface of substrate 150 to be positioned at picture 102 places, plane, and without the side of surface of contact to the catoptron 810 on picture plane 102.

Similarly, the free operating distance of thing side refer to object plane 103 and in projection objective 101 bee-line between the minute surface of the reflecting surface of the catoptron of the object plane 103 of close optical reflection imaging.In certain embodiments, projection objective 101 has the bigger free operating distance of thing side, for example, projection objective 101 can have the free operating distance of thing side more than or equal to about 50mm (for example, more than or equal to about 100mm, more than or equal to about 150mm, more than or equal to about 200mm, more than or equal to about 250mm, more than or equal to about 300mm, more than or equal to about 350mm, more than or equal to about 400mm, more than or equal to about 450mm, more than or equal to about 500mm, more than or equal to about 550mm, more than or equal to about 600mm, more than or equal to about 650mm, more than or equal to about 700mm, more than or equal to about 750mm, more than or equal to about 800mm, more than or equal to about 850mm, more than or equal to about 900mm, more than or equal to about 950mm, more than or equal to about 1000mm).In a particular embodiment, the free operating distance of thing side is not more than about 2000mm (for example, be less than or equal to about 1500mm, be less than or equal to about 1200mm, be less than or equal to about 1000mm).For example, projection objective 300 has the free operating distance of thing side of about 300mm.Enter among the embodiment in the space between projection objective 101 and the object plane 103 in hope, the bigger free operating distance of thing side is favourable.For example, be among the embodiment of reflection modulation dish at chopper wheel 140, need be from facing the side irradiation chopper wheel of object lens 101.Therefore, this just requires between projection objective 101 and object plane 103 enough spaces are arranged, to allow by the irradiating angle irradiation chopper wheel of irradiation system 120 with hope.And, usually, the bigger free operating distance of thing side makes to have dirigibility in the design of other parts of instrument, for example, by between the supporting construction of projection objective 101 and chopper wheel 140, providing enough space so that miscellaneous part (for example, evenly filtrator) to be installed.

Usually, projection objective 101 is designed to chief ray or convergence, disperses or is parallel to each other substantially at chopper wheel 140 places.Correspondingly, corresponding to object plane 103, the entrance pupil position changeable of projection objective 101.For example, under the situation that chopper wheel 140 place's chief rays are assembled, entrance pupil is positioned at picture plane one side of object plane 103.On the contrary, under the situation that chopper wheel 140 place's chief rays are dispersed, object plane 103 is between entrance pupil and picture plane 102.And, the distance variable between object plane 103 and entrance pupil.In certain embodiments, entrance pupil apart from object plane 103 (measuring along the axle perpendicular to object plane 103) more than or equal to the 1m place (for example approximately is positioned at, more than or equal to about 2m, more than or equal to about 3m, more than or equal to about 4m, more than or equal to about 5m, more than or equal to about 8m, more than or equal to about 10m).In certain embodiments, the relative object plane 103 of entrance pupil is positioned at infinite distant place.This is corresponding in chopper wheel 140 places, the situation that chief ray is parallel to each other.For projection objective 300, on object plane 103, the angle of chief ray incident central field point is 7 °, and the maximum variation that forms the chief ray angle of central field point chief ray is 0.82 °.Entrance pupil object plane 103 with the relative side in picture plane 102, be 1000mm apart from object plane 103.

Irradiation system 120 can be arranged so that the emergent pupil of irradiation system is positioned at the entrance pupil place of projection objective 101 substantially.In a particular embodiment, irradiation system 120 comprises the telescope subsystem, and its emergent pupil with irradiation system projects to the entrance pupil position of projection objective 101.Yet in certain embodiments, the emergent pupil of irradiation system 120 is positioned at the entrance pupil place of projection objective 101, and does not use telescope in irradiation system.For example, when object plane 103 was between the entrance pupil of projection objective 101 and projection objective, the emergent pupil of irradiation system 120 can be consistent with the entrance pupil of projection objective, and do not use telescope in irradiation system.

Usually, projection objective 101 can use can the commercial optical design software that obtains, and for example ZEMAX, OSLO or Code V design.Usually, for example, the initial designs (for example placement of catoptron) by specifying projection objective and the parameter of optical wavelength, a size and numerical aperture for example, and begin design.Then, for the optical property standard of appointment, as wavefront error, distortion, disposition far away and field curvature etc., described code optimization design.

In a particular embodiment, initial projection objective is represented by the rotation symmetry catoptron (for example, sphere or aspheric catoptron) that is positioned at optical axis center.Then, each catoptron from optical axis off-centre to making catoptron satisfy the position of some preassigneds.For example, each catoptron can be a certain amount of from optical axis off-centre, and this amount minimizes the incident chief ray angle by catoptron for specific field.In an embodiment, catoptron is eccentric more than or equal to about 5mm (for example, more than or equal to about 10mm, more than or equal to about 20mm, more than or equal to about 30mm, more than or equal to about 50mm).In a particular embodiment, catoptron is eccentric in being less than or equal to about 200mm (for example, be less than or equal to about 180mm, be less than or equal to about 150mm, be less than or equal to about 120mm, be less than or equal to about 100mm).

Be that perhaps in addition, each catoptron tiltable makes catoptron satisfy some preassigneds to a certain position alternatively.This inclination refers to the orientation of each catoptron axis of symmetry with respect to the optical axis of the initial configuration of projection objective.The catoptron tiltable is more than or equal to about 1 ° (for example, more than or equal to about 2 °, more than or equal to about 3 °, more than or equal to about 4 °, more than or equal to about 5 °).In certain embodiments, the catoptron tiltable is less than or equal to about 20 ° (for example, are less than or equal to about 15 °, are less than or equal to about 12 °, be less than or equal to about 10 °).

After eccentric and/or inclination, can determine the free type surface of each catoptron, with at concrete optical property standard, optimize projection objective optimization.

Except catoptron, projection objective 101 can comprise one or more miscellaneous part, for example one or more aperture diaphragms.Usually, the shape variable of aperture diaphragm.The example of aperture diaphragm comprises circular aperture diaphragm, oval aperture diaphragm and or polygon aperture diaphragm.Aperture diaphragm also can be placed as, make twice of imaging by or once pass through aperture diaphragm.Aperture diaphragm in the projection objective 101 can exchange mutually, and/or have an adjustable aperture.

In certain embodiments, projection objective 101 comprises field diaphragm.For example, comprise among the embodiment of intermediary image at projection objective, field diaphragm can be placed on the intermediary image place or near.

Embodiment can comprise dividing plate (for example, cover wafer and avoid parasitic light).In certain embodiments, projection objective 101 can comprise the element that the reflector position that is used for monitoring projection objective changes.These information can be used to the accommodation reflex mirror to proofread and correct any the relatively moving between the catoptron.The catoptron adjustment can robotization.The example of system that is used to monitor/adjust reflector position is at U.S.6, and 549, open among the 270B1.

With reference to Figure 10, the embodiment of projection objective 1000 comprises the embodiment of six

catoptrons

1010,1020,1030,1040,1050 and 1060, has 0.35 picture side numerical aperture and the operation wavelength of 13.5nm.

Catoptron

1010,1020,1030,1040,1050 and 1060 all is the free type catoptron.Projection objective 1000 will arrive picture plane 102 from the photoimaging of object plane 103 with the minification of 4X.The track lenth of projection objective 1000 is 1497mm, and the optical path length of imaging is 4760mm.Thereby the ratio of optical path length and track lenth approximately is 3.18.

The entrance pupil of projection objective 1000 is positioned at the 1000mm place apart from object plane 103, and object plane is between entrance pupil and catoptron.Because the reflection modulation dish is positioned at object plane 103 places, the irradiates light device can be positioned at 1070 places, position, corresponding to entrance pupil.The chief ray angle of central field point is 7 ° on the object plane 103.The maximum variable quantity of 103 chief ray angle is 0.82 ° on the object plane.

Projection objective 1000 has rectangular field.Picture side field width degree d _xBe 26mm, as side field length d _yBe 2mm.Projection objective 1000 has the image skew of 13mm.

The performance of projection objective 1000 comprises the picture side W of 0.021 λ _RmsDistortion is less than 10nm, and is 19nm as the side field curvature.Projection objective 1000 provides the intermediary image between catoptron 1040 and 1050.The coma at intermediary image place is bigger.Particularly, the distance between chief ray and the upper and lower light at upper and lower light infall is 7mm.

Power of mirror is as follows in order to looking like on the light path on plane 102 from object plane 103: catoptron 1010 has positive light coke, catoptron 1020 has negative power, catoptron 1030 has positive light coke, catoptron 1040 has positive light coke, catoptron 1050 has negative power, and catoptron 1060 has positive light coke.

The size of the occupy-place face of each catoptron is given as M _x* M _y, as follows: catoptron 1010 is 323mm * 152mm, and catoptron 1020 is 107mm * 59mm, and catoptron 1030 is 297mm * 261mm, and catoptron 1040 is 277mm * 194mm, and catoptron 1050 is 99mm * 72mm, and catoptron 1060 is 268mm * 243mm.

Catoptron 1010 is 475 μ m from the maximum deviation of best-

fit sphere.Catoptron

1020,1030,1040,1050 and 1060 maximum deviation from the best-fit sphere are respectively 1234 μ m, 995 μ m, 1414 μ m, 170 μ m and 416 μ m.Each catoptron is respectively 236 μ m, 102 μ m, 102 μ m, 148 μ m, 54 μ m and 327 μ m from the aspheric maximum deviation of best-fit for

catoptron

1010,1020,1030,1040,1050 and 1060.

First and second principal curvaturess of catoptron 1010 are respectively 1.16 * 10 ^-3With 1.05 * 10 ^-3For other catoptrons in the projection objective 1000, first and second principal curvaturess are as follows respectively: catoptron 1020 is-3.02 * 10 ^-3With-1.13 * 10 ^-3, catoptron 1030 is 5.97 * 10 ^-4With 4.96 * 10 ^-4, catoptron 1040 is 5.50 * 10 ^-4With 3.63 * 10 ^-4, catoptron 1050 is-2.24 * 10 ^-3With-2.04 * 10 ^-3, catoptron 1060 is 2.57 * 10 ^-3With 2.48 * 10 ^-3First principal curvatures of projection objective 1000 and be-3.78 * 10 ^-4The second principal curvatures sum is 1.22 * 10 ^-3The first and second principal curvatures sums 8.45 * 10 ^-4, and the inverse of the first and second principal curvatures sums is 1.18 * 10 ³

The incident chief ray angle of central field point for

catoptron

1010,1020,1030,1040,1050 and 1060, is respectively 3.40 °, 9.86 °, 6.48 °, 10.13 °, 13.66 ° and 7.00 °.The maximum incident angle degree θ of each catoptron on the meridian cross section _Max, be respectively 3.94 °, 10.42 °, 7.45 °, 14.34 °, 24.28 ° and 8.61 ° for

catoptron

1010,1020,1030,1040,1050 and 1060.For

catoptron

1010,1020,1030,1040,1050 and 1060, Δ θ is respectively 1.13 °, 2.74 °, 3.42 °, 9.96 °, 23.69 ° and 3.95 °.

Catoptron

1010,1020,1030,1050 and 1060 has greater than 5mm and less than the freeboard of 25mm.Catoptron 1030 has positive chief ray angle magnification, and

catoptron

1040 and 1050 has negative chief ray angle magnification.

Projection objective 1000 be 45mm as the free operating distance of side.The free operating distance of thing side is 252mm.

In projection objective 1000, d _Op-1/ d _Op-2Be 3.14.And adjacent mirror is to 1020 and 1030,1030 and 1040, and 1040 and 1050 are separated by the projection objective track lenth greater than 50%.And the distance between catoptron 1010 and object plane 103 is greater than 50% of projection objective track lenth.

Shown in the related data of projection objective 1000 table 2A below and the table 2B.Table 2A and show 2B and table subsequently in parameter and parameter unit all be with top table 1A and 1B in corresponding parameter identical with unit.Table 2A shows optical data, and table 2B shows the free type constant for each mirror surface.In order to show the purpose of 2A and table 2B, the following correspondence of catoptron title: catoptron 1 (M1) is corresponding to catoptron 1010, catoptron 2 (M2) is corresponding to catoptron 1020, catoptron 3 (M3) is corresponding to catoptron 1030, catoptron 4 (M4) is corresponding to catoptron 1040, catoptron 5 (M5) is corresponding to catoptron 1050, and catoptron 6 (M6) is corresponding to catoptron 1060.

Table 2A

Table 2B

With reference to Figure 11, the embodiment of projection objective 1000 comprises

catoptron

1110,1120,1130,1140,1150 and 1160, and has 0.35 picture side numerical aperture and the operation wavelength of 13.5nm.

Catoptron

1110,1120,1130,1140,1150 and 1160 all is the free type catoptron.Projection objective 1100 will be from the photoimaging of object plane 103 to picture plane 102 with the minification of 4X.The track lenth of projection objective 1100 is 2000mm, and the optical path length of imaging is 5337mm.Therefore, the ratio of optical path length and track lenth approximately is 2.67.Projection objective 1100 has the aperture diaphragm 1106 that is placed on catoptron 1120 places.

The entrance pupil of projection objective 1100 is positioned at infinite distant place.The chief ray angle of central field point is 7 ° on the object plane 103.The maximum variable quantity of chief ray angle is less than 0.06 ° on the object plane 103.

Projection objective 1100 has rectangular field.Picture side field width degree d _xBe 26mm.Picture side field length d _yBe 2mm.Projection objective 1100 has the image skew of 31mm.

The performance of projection objective 1100 comprises the picture side W of 0.025 λ _RmsAs the side field curvature is 10nm.Projection objective 1100 provides the intermediary image between

catoptron

1140 and 1150.

Power of mirror is as follows in order to looking like on the light path on plane 102 at object plane 103: catoptron 1110 has positive light coke, catoptron 1120 has positive light coke, catoptron 1130 has negative power, catoptron 1140 has positive light coke, catoptron 1150 has negative power, and catoptron 1160 has positive light coke.

The size of the occupy-place face of each catoptron is given as M _x* M _y, as follows: catoptron 1110 is 291mm * 195mm, and catoptron 1120 is 159mm * 152mm, and catoptron 1130 is 157mm * 53mm, and catoptron 1140 is 295mm * 66mm, and catoptron 1150 is 105mm * 86mm, and catoptron 1160 is 345mm * 318mm.

The incident chief ray angle of central field point for

catoptron

1110,1120,1130,1140,1150 and 1160, is respectively 4.38 °, 4.03 °, 18.37 °, 7.74 °, 12.64 ° and 5.17 °.The maximum incident angle degree θ of each catoptron on the meridian cross section _Max, be respectively 6.48 °, 6.44 °, 20.05 °, 9.12 °, 21.76 ° and 7.22 ° for

catoptron

1110,1120,1130,1140,1150 and 1160.For

catoptron

1110,1120,1130,1140,1150 and 1160, Δ θ is respectively 4.27 °, 4.92 °, 4.09 °, 3.12 °, 19.37 ° and 4.61 °.

Catoptron

1110,1150 and 1160 has greater than 5mm and less than the freeboard of 25mm.Catoptron 1140 has positive chief ray angle magnification, and

catoptron

1110,1120,1130 and 1150 has negative chief ray angle magnification.

Projection objective 1000 be 25mm as the free operating distance of side.The free operating distance of thing side is 163mm.

In projection objective 1100, d _Op-1/ d _Op-2Be 6.57.And adjacent mirror is separated by the projection objective track lenth greater than 50% 1040 and 1050.And the distance between catoptron 1110 and object plane 103 is greater than 50% of projection objective track lenth.

Shown in the related data of projection objective 1100 table 3A below and the table 3B.Table 3A shows optical data, and table 3B shows the aspheric surface constant of each mirror surface.In table 3A and table 3B, the following correspondence of the title of catoptron: catoptron 1 (M1) is corresponding to catoptron 1110, catoptron 2 (M2) is corresponding to catoptron 1120, catoptron 3 (M3) is corresponding to catoptron 1130, catoptron 4 (M4) is corresponding to catoptron 1140, catoptron 5 (M5) is corresponding to catoptron 1150, and catoptron 6 (M6) is corresponding to catoptron 1160.

Table 3A

Table 3B

With reference to Figure 12, the embodiment of projection objective 1200 comprises six catoptrons 1210,1220,1230,1240,1250 and 1260, and has 0.35 picture side numerical aperture and the operation wavelength of 13.5nm.

Catoptron

1210,1220,1230,1240,1250 and 1260 all is the free type catoptron.Projection objective 1200 will be from object plane 103 photoimagings to picture plane 102 with the minification of 4X.Axis of reference 1205 perpendicular to object plane 103 and picture plane 102, intersects with corresponding point in thing field and the image field.The track lenth of projection objective 1200 is 1385mm, and the optical path length of imaging is 4162mm.Thereby the ratio of optical path length and track lenth approximately is 3.01.Projection objective 1200 has the aperture diaphragm that is positioned over catoptron 1220 places.

The entrance pupil of projection objective 1200 is positioned at infinite distant place, and object plane is between entrance pupil and catoptron.The chief ray angle of central field point is 7 ° on the object plane 103.The maximum variable quantity of 103 chief ray angle is 0.06 ° on the object plane.

Projection objective 1200 has rectangular field.Picture side field width degree d _xBe 26mm, as side field length d _yBe 2mm.Projection objective 1200 has zero image skew.

Projection objective 1200 provides the intermediary image between

catoptron

1240 and 1250.

Power of mirror is as follows in order to looking like on the light path on plane 102 from object plane 103: catoptron 1210 has positive light coke, catoptron 1220 has negative power, catoptron 1230 has positive light coke, catoptron 1240 has positive light coke, catoptron 1250 has negative power, and catoptron 1260 has positive light coke.

The size of the occupy-place face of each catoptron is given as M _x* M _y, as follows: catoptron 1210 is 250mm * 153mm, and catoptron 1220 is 70mm * 69mm, and catoptron 1230 is 328mm * 153mm, and catoptron 1240 is 325mm * 112mm, and catoptron 1250 is 87mm * 75mm, and catoptron 1260 is 269mm * 238mm.

The incident chief ray angle of central field point for

catoptron

1210,1220,1230,1240,1250 and 1260, is respectively 6.13 °, 10.61 °, 8.65 °, 8.26 °, 14.22 ° and 5.23 °.The maximum incident angle degree θ of each catoptron on the meridian cross section _Max, be respectively 6.53 °, 11.63 °, 8.91 °, 11.39 °, 24.26 ° and 7.44 ° for

catoptron

1210,1220,1230,1240,1250 and 1260.For

catoptron

1210,1220,1230,1240,1250 and 1260, Δ θ is respectively 1.07 °, 3.64 °, 1.74 °, 7.44 °, 21.70 ° and 4.51 °.

Catoptron

1210,1220,1250 and 1260 has greater than 5mm and less than the freeboard of 25mm.Catoptron 1240 has positive chief ray angle magnification, and

catoptron

1210,1220,1230 and 1250 has negative chief ray angle magnification.

Projection objective 1200 be 40mm as the free operating distance of side.The free operating distance of thing side is 439mm.

In projection objective 1200, d _Op-1/ d _Op-2Be 1.91.And adjacent mirror is separated by the projection objective track lenth greater than 50% 1240 and 1250.And the distance between catoptron 1210 and object plane 103 is greater than 50% of projection objective track lenth.

Shown in the related data of projection objective 1200 table 4A below and the table 4B.Table 4A shows optical data, and table 4B shows the free type constant of each mirror surface.In table 4A and table 4B, the following correspondence of the title of catoptron: catoptron 1 (M1) is corresponding to catoptron 1210, catoptron 2 (M2) is corresponding to catoptron 1220, catoptron 3 (M3) is corresponding to catoptron 1230, catoptron 4 (M4) is corresponding to catoptron 1240, catoptron 5 (M5) is corresponding to catoptron 1250, and catoptron 6 (M6) is corresponding to catoptron 1260.

Table 4A

Table 4B

With reference to Figure 13, the embodiment of projection objective 1300 comprises six catoptrons 1310,1320,1330,1340,1350 and 1360, and has 0.35 picture side numerical aperture and the operation wavelength of 13.5nm.

Catoptron

1310,1320,1330,1340,1350 and 1360 all is the free type catoptron.Projection objective 1300 will arrive picture plane 102 from the photoimaging of object plane 103 with the minification of 4X.The track lenth of projection objective 1300 is 1500mm, and the optical path length of imaging is 4093mm.Thereby the ratio of optical path length and track lenth approximately is 2.73.Projection objective 1300 has the aperture diaphragm that is positioned at catoptron 1320 places.

The entrance pupil of projection objective 1300 is positioned at infinite distant place.The chief ray angle of central field point is 7 ° on the object plane 103.The maximum variable quantity of 103 chief ray angle is less than 0.1 ° on the object plane.

Projection objective 1300 has rectangular field.Picture side field width degree d _xBe 26mm, as side field length d _yBe 2mm.Projection objective 1300 has the image skew of 119mm.

Projection objective 1300 provides the intermediary image between

catoptron

1340 and 1350.

Power of mirror is as follows in order to looking like on the light path on plane 102 from object plane 103: catoptron 1310 has positive light coke, catoptron 1320 has negative power, catoptron 1330 has positive light coke, catoptron 1340 has positive light coke, catoptron 1350 has negative power, and catoptron 1360 has positive light coke.

The size of the occupy-place face of each catoptron is given as M _x* M _y, as follows: catoptron 1310 is 271mm * 173mm, and catoptron 1320 is 69mm * 65mm, and catoptron 1330 is 290mm * 115mm, and catoptron 1340 is 272mm * 66mm, and catoptron 1350 is 81mm * 67mm, and catoptron 1360 is 274mm * 243mm.

For

catoptron

1310,1320,1330,1340,1350 and 1360, the incident chief ray angle of central field point is respectively 9.66 °, 12.15 °, 9.10 °, 5.45 °, 13.31 ° and 4.60 °.For

catoptron

1310,1320,1330,1340,1350 and 1360, the maximum incident angle degree θ of each catoptron on the meridian cross section _MaxIt is respectively 11.20 °, 15.46 °, 9.63 °, 8.64 °, 23.31 ° and 6.17 °.For

catoptron

1310,1320,1330,1340,1350 and 1360, Δ θ is respectively 3.25 °, 7.32 °, 1.57 °, 6.92 °, 21.18 ° and 3.63 °.

Catoptron 1340 has positive chief ray angle magnification, and

catoptron

1310,1320,1330 and 1350 has negative chief ray angle magnification.Projection objective 1300 be 40mm as the free operating distance of side.The free operating distance of thing side is 582mm.The free operating distance of this big thing side allows to insert miscellaneous part, particularly irradiation system, and for example, folding mirror or homogeneity filtrator are injected in additional plunderring.

In projection objective 1300, d _Op-1/ d _Op-2Be 1.63.And adjacent mirror is separated by the projection objective track lenth greater than 50% 1340 and 1350.And the distance between catoptron 1310 and object plane 103 is greater than 50% of projection objective track lenth.

Shown in the related data of projection objective 1300 table 5A below and the table 5B.Table 5A shows optical data, and table 5B shows the aspheric surface constant of each mirror surface.In table 5A and table 5B, the following correspondence of the title of catoptron: catoptron 1 (M1) is corresponding to catoptron 1310, catoptron 2 (M2) is corresponding to catoptron 1320, catoptron 3 (M3) is corresponding to catoptron 1330, catoptron 4 (M4) is corresponding to catoptron 1340, catoptron 5 (M5) is corresponding to catoptron 1350, and catoptron 6 (M6) is corresponding to catoptron 1360.

Table 5A

Table 5B

With reference to figure 14A, the embodiment of projection objective 1400 comprises six catoptrons 1410,1420,1430,1440,1450 and 1460, and has 0.40 picture side numerical aperture and the operation wavelength of 13.5nm.

Catoptron

1410,1420,1430,1440,1450 and 1460 all is the free type catoptron.Projection objective 1400 will arrive picture plane 102 from the photoimaging of object plane 103 with the minification of 4X.The track lenth of projection objective 1400 is 1498mm, and the optical path length of imaging is 3931mm.Thereby the ratio of optical path length and track lenth approximately is 2.62.Projection objective 1300 has the pupil plane that places between

catoptron

1420 and 1430.

The entrance pupil of projection objective 1400 is positioned at the 1000mm place apart from object plane 103, and object plane is between entrance pupil and catoptron.The chief ray angle of central field point is 7 ° on the object plane 103.The maximum variable quantity of 103 chief ray angle is 0.82 ° on the object plane.

Projection objective 1400 has rectangular field.Picture side field width degree d _xBe 26mm, as side field length d _yBe 2mm.Projection objective 1400 has the image skew of 38mm.

The performance of projection objective 1400 comprises the picture side W of 0.083 λ _RmsDistortion approximately is 100nm, and is 36nm as the side field curvature.Projection objective 1400 provides the intermediary image between

catoptron

1440 and 1450.

Power of mirror is as follows in order to looking like on the light path on plane 102 from object plane 103: catoptron 1410 has positive light coke, catoptron 1420 has positive light coke, catoptron 1430 has negative power, catoptron 1440 has positive light coke, catoptron 1450 has negative power, and catoptron 1360 has positive light coke.

The size of the occupy-place face of each catoptron is given as M _x* M _y, as follows: catoptron 1410 is 326mm * 159mm, catoptron 1420 is 210mm * 123mm, catoptron 1430 is 120mm * 66mm, catoptron 1440 is 312mm * 119mm, and catoptron 1450 is 112mm * 83mm, and catoptron 1460 is 405mm * 379mm.

For

catoptron

1410,1420,1430,1440,1450 and 1460, the incident chief ray angle of central field point is respectively 6.70 °, 8.08 °, 20.41 °, 6.68 °, 14.52 ° and 5.67 °.For

catoptron

1410,1420,1430,1440,1450 and 1460, the maximum incident angle degree θ of each catoptron on the meridian cross section _MaxIt is respectively 8.61 °, 10.91 °, 21.98 °, 7.41 °, 27.19 ° and 6.86 °.For

catoptron

1410,1420,1430,1440,1450 and 1460, Δ θ is respectively 3.92 °, 5.69 °, 3.82 °, 1.79 °, 26.83 ° and 3.20 °.

Catoptron

1410,1420,1430,1450 and 1460 has greater than 5mm and less than the freeboard of 25mm.Catoptron 1440 has positive chief ray angle magnification, and

catoptron

1410,1420,1430 and 1450 has negative chief ray angle magnification.

Projection objective 1400 be 45mm as the free operating distance of side.The free operating distance of thing side is 291mm.

In projection objective 1400, d _Op-1/ d _Op-2Be 2.47.And adjacent mirror is separated by the projection objective track lenth greater than 50% 1440 and 1450.

Shown in the related data of projection objective 1400 table 6A below and the table 6B.Table 6A shows optical data, and table 6B shows the aspheric surface constant of each mirror surface.In table 6A and table 6B, the following correspondence of the title of catoptron: catoptron 1 (M1) is corresponding to catoptron 1410, catoptron 2 (M2) is corresponding to catoptron 1420, catoptron 3 (M3) is corresponding to catoptron 1430, catoptron 4 (M4) is corresponding to catoptron 1440, catoptron 5 (M5) is corresponding to catoptron 1450, and catoptron 6 (M6) is corresponding to catoptron 1460.

Table 6A

Table 6B

With reference to figure 14B, projection objective 1400 can be used in the optical system 1401, it comprises light source 1405 and illumination optical element, and described illumination optical element comprises collector unit 1415, spectral purity filtrator 1425, a facet mirrors 1435 and pupil facet mirrors 1445.Light source 1405 is EUV light sources, is set to provide the light of 13.5nm wavelength to projection objective.Collector unit 1415 is collected from the light of light source 1405, and light is directed to spectral purity filtrator 1415, and described filtrator is crossed the incident light beyond the filtering 13.5nm wavelength, and the light of 13.5nm is guided the facet mirrors 1435 of showing up.With pupil facet mirrors 1445, a facet mirrors is positioned at the reflection modulation dish at object plane 103 places with the rayed of 13.5nm.Provide illumination to make chief ray disperse from chopper wheel.In this way illumination is offered chopper wheel, and need not use additional parts, for example, plunder to inject and penetrate catoptron.

With reference to Figure 15, projection objective 1500 comprises the embodiment of six

catoptrons

1510,1520,1530,1540,1550 and 1560, and has 0.40 picture side numerical aperture and the operation wavelength of 13.5nm.

Catoptron

1510,1520,1530,1540,1550 and 1560 all is the free type catoptron.Projection objective 1500 will arrive picture plane 102 from the photoimaging of object plane 103 with the minification of 4X.The track lenth of projection objective 1500 is 1499mm, and the optical path length of imaging is 4762mm.Thereby the ratio of optical path length and track lenth approximately is 3.18.

The entrance pupil of projection objective 1500 is positioned at the 1000mm place apart from object plane 103, and object plane is between entrance pupil and catoptron.Owing to be positioned at the reflection modulation dish of object plane 103, the illumination optical element particularly has the catoptron of pupil facet, can be positioned over 1501 places, position corresponding to entrance pupil.The chief ray angle of central field point is 7 ° on the object plane 103.The maximum variable quantity of 103 chief ray angle is 0.82 ° on the object plane.

Projection objective 1500 has rectangular field.Picture side field width degree d _xBe 26mm, as side field length d _yBe 2mm.Projection objective 1500 has the image skew of 7mm.

The performance of projection objective 1500 comprises the picture side W of 0.040 λ _RmsAlso with reference to figure 16A, distortion is less than about 3nm on the image field.As the side field curvature is 35nm.Projection objective 1500 provides the intermediary image between catoptron 1540 and 1550.With reference to figure 16B, chief ray on image field, in the scope of about 0.001rad (0.06 °) perpendicular to looking like plane 102.

Power of mirror is as follows in order to looking like on the light path on plane 102 from object plane 103: catoptron 1510 has positive light coke, catoptron 1520 has negative power, catoptron 1530 has positive light coke, catoptron 1540 has positive light coke, catoptron 1550 has negative power, and catoptron 1560 has positive light coke.

The size of the occupy-place face of each catoptron is given as M _x* M _y, as follows: catoptron 1510 is 253mm * 162mm, catoptron 1520 is 105mm * 66mm, catoptron 1530 is 227mm * 301mm, catoptron 1540 is 182mm * 220mm, and catoptron 1550 is 111mm * 85mm, and catoptron 1560 is 289mm * 275mm.

For

catoptron

1510,1520,1530,1540,1550 and 1560, the incident chief ray angle of central field point is respectively 3.96 °, 12.21 °, 7.51 °, 11.98 °, 15.82 ° and 8.08 °.For

catoptron

1510,1520,1530,1540,1550 and 1560, the maximum incident angle degree θ of each catoptron on the meridian cross section _MaxIt is respectively 4.47 °, 12.81 °, 8.55 °, 16.91 °, 27.68 ° and 9.96 °.For

catoptron

1510,1520,1530,1540,1550 and 1560, Δ θ is respectively 1.10 °, 3.61 °, 4.19 °, 12.12 °, 27.17 ° and 4.79 °.

Catoptron

1510,1520,1540,1550 and 1560 has greater than 5mm and less than the freeboard of 25mm.Catoptron 1530 has positive chief ray angle magnification, and

catoptron

1510,1520,1540 and 1550 has negative chief ray angle magnification.

Projection objective 1500 be 45mm as the free operating distance of side.The free operating distance of thing side is 260mm.

In projection objective 1500, d _Op-1/ d _Op-2Be 3.05.And adjacent mirror is separated by the projection objective track lenth greater than 50% 1520 and 1530,1530 and 1540,1540 and 1550.And the distance between catoptron 1510 and object plane 103 is greater than 50% projection objective track lenth.

Shown in the related data of projection objective 1500 table 7A below and the table 7B.Table 7A shows optical data, and table 7B shows the aspheric surface constant of each mirror surface.In table 7A and table 7B, the following correspondence of the title of catoptron: catoptron 1 (M1) is corresponding to catoptron 1510, catoptron 2 (M2) is corresponding to catoptron 1520, catoptron 3 (M3) is corresponding to catoptron 1530, catoptron 4 (M4) is corresponding to catoptron 1540, catoptron 5 (M5) is corresponding to catoptron 1550, and catoptron 6 (M6) is corresponding to catoptron 1560.

Table 7A

Table 7B

Figure 17 to 20 shows another embodiment of the present invention, and it has four catoptrons that are designed to the free type curved surface.Show object plane 3000, as plane 3002, the first catoptron S1, the second catoptron S2, the 3rd catoptron S3, the 4th catoptron S4.The table of optical data below all is expressed as M1 to M4 with catoptron S1 to S4.For embodiment, provide following data according to Figure 17 to 20:

Numerical aperture: 0.26

The imaging factor: 1: 4

Thing field shape: rectangle

Thing side scanning field width: 100mm

Thing side scanning field height: 8mm

Length: 2360mm

Picture plane inclination :-3.084 °

This embodiment show have numerical aperture, the system of the balanced combination of size, system dimension, wavefront and distortion correction.

Optical data shown in the following table:

x _Thing/mmy _Thing/mmThe distortion distortion distorts 13,5nm's

The heart far away/degree

(x)/nm (y)/nm absolute value/nm wavefront error

0 600 0 -0.960073 0.960073 0.0196465 0.027195

0 602 0 -1.46082 1.46082 0.0111602 0.019766

0 604 0 -1.14157 1.14157 0.00258716 0.015522

0 606 0 -0.708422 0.708422 0.00607316 0.01395

0 608 0 -0.868087 0.868087 0.0148213 0.032279

12.5 600 -0.702813 -0.349919 0.785105 0.0226563 0.026075

12.5 602 -0.506161 -0.815296 0.959639 0.0159931 0.018251

12.5 604 -0.214821 -0.491402 0.536306 0.011916 0.01476

12.5 606 0.161171 -0.084304 0.181888 0.0132822 0.014764

12.5 608 0.611783 -0.300692 0.681685 0.0190686 0.032953

25 600 -0.828473 0.99838 1.29736 0.0299227 0.025603

25 602 -0.613329 0.633853 0.882011 0.0254871 0.014924

25 604 -0.210678 0.966257 0.988958 0.0234105 0.012561

25 606 0.359349 1.28961 1.33874 0.0243974 0.016745

25 608 1.07663 0.89729 1.40152 0.028208 0.035061

37.5 600 -0.079109 1.6231 1.62502 0.0391462 0.033551

37.5 602 -0.207297 1.40928 1.42444 0.036144 0.015412

37.5 604 -0.058849 1.73794 1.73893 0.035006 0.008795

37.5 606 0.335888 1.90321 1.93262 0.0359723 0.018708

37.5 608 0.946577 1.1986 1.5273 0.0389452 0.038658

50 600 1.28921 -0.96207 1.60861 0.0492443 0.056489

50 602 0.261464 -1.00092 1.03450 0.0471902 0.03219

50 604 -0.405953 -0.714664 0.821914 0.0466375 0.018965

50 606 -0.753775 -0.809016 1.10575 0.0476858 0.02652

50 608 -0.82272 -1.99027 2.15361 0.0502807 0.047096

x _Thing/mmAnd y _Thing/mmX coordinate and y coordinate in the expression object plane.Value distortion (x) and distortion (y) are illustrated in the distortion of corresponding coordinate.Distortion absolute value on the corresponding coordinate axle that the absolute value/nm of distortion has represented to measure on as the plane.The heart/kilsyth basalt far away has shown the chief ray angle of each coordinate.13.5nm wavefront error represent RMS wavefront error in the light illuminating unit of wavelength X=13.5nm.Because optical system in the face of claiming, therefore, is enough to be provided at the data that have positive x seat aiming field point in the object plane with respect to the yz level crossing.

Figure 18 to 20 shows according to Figure 17, the lateral aberration in the emergent pupil coordinate system of object lens.These aberrations show the wavefront error of 15 field points, that is, and and at x=0, x=x _Max/ 2 and x=x _MaxThe center, thing field at place is at y _MinAnd y _MaxBetween five equidistant y coordinates.

Figure 21 to 24 shows another embodiment of the present invention, and it has four catoptrons that are designed to the free type curved surface.Show object plane 3000, as plane 3002, the first catoptron S1, the second catoptron S2, the 3rd catoptron S3, the 4th catoptron S4.The table of optical data below all is expressed as M1 to M4 with catoptron S1 to S4.For embodiment, provide following data according to Figure 21 to 24:

Numerical aperture: 0.3

The imaging factor: 1: 4

Thing field shape: rectangle

Thing side scanning field width: 100mm

Thing side scanning field height: 8mm

Length: 2354mm

Picture plane inclination :-3.798 °

This embodiment shows has the system that has increased numerical aperture.

Optical data can obtain from following table:

x _Thing/mmy _Thing/mmThe distortion distortion distorts 13,5nm's

The heart far away/degree

(x)/nm (y)/nm absolute value/nm wavefront error

0 600 0 -2.20023 2.20023 0.0179382 0.046032

0 602 0 -1.79021 1.79021 0.0109101 0.029756

0 604 0 -1.28717 1.28717 0.00378722 0.023987

0 606 0 -0.891336 0.891336 0.00343113 0.017834

0 608 0 -0.799202 0.799202 0.0107455 0.043696

12.5 600 -1.08427 -1.27001 1.66991 0.0239704 0.043224

12.5 602 -0.470847 -0.877877 0.996175 0.0193253 0.026959

12.5 604 0.0397523 -0.421226 0.423098 0.0164496 0.024212

12.5 606 0.437494 -0.10014 0.448809 0.016432 0.020337

12.5 608 0.712381 -0.110954 0.72097 0.0193876 0.042811

25 600 -1.45171 0.861628 1.68815 0.0365032 0.04072

25 602 -0.473724 1.1945 1.28501 0.0337094 0.021812

25 604 0.296494 1.50628 1.53518 0.0322325 0.025914

25 606 0.838851 1.59734 1.80421 0.0323169 0.027051

25 608 1.13332 1.27182 1.70351 0.0340121 0.041958

37.5 600 -0.729082 2.21013 2.32728 0.0509314 0.052463

37.5 602 0.112795 2.42562 2.42824 0.0490538 0.021672

37.5 604 0.637771 2.47706 2.55785 0.0481478 0.026628

37.5 606 0.815622 2.16558 2.31408 0.0483103 0.033809

37.5 608 0.616222 1.29608 1.43512 0.0495729 0.044712

50 600 0.775128 -0.556886 0.954435 0.0660057 0.083092

50 602 0.722695 -0.544482 0.904847 0.0646623 0.033187

50 604 0.238001 -0.896861 0.927904 0.0640826 0.022442

50 606 -0.719402 -1.81183 1.94942 0.0643192 0.040278

50 608 -2.18984 -3.48339 4.11454 0.0653953 0.058456

Figure 22 to 24 shows according to Figure 21, the lateral aberration in the emergent pupil coordinate system of object lens.

Figure 25 to 28 shows another embodiment of the present invention, and it has four catoptrons that are designed to the free type curved surface.Show object plane 3000, as plane 3002, the first catoptron S1, the second catoptron S2, the 3rd catoptron S3, the 4th catoptron S4.Below all, in the table of optical data, catoptron S1 is expressed as M1 to M4 to S4.For embodiment, provide following data according to Figure 25 to 28:

Numerical aperture: 0.25

The imaging factor: 1: 5

Thing field shape: rectangle

Thing side scanning field width: 100mm

Thing side scanning field height: 8mm

Length: 3030mm

Picture plane inclination: 0 °

This embodiment shows the system with parallel principal plane.

And this embodiment illustrates the different imaging factor of knowing clearly 1: 5.

Optical data can obtain from following table:

x _Thing/mmy _Thing/mmThe distortion distortion distorts 13,5nm's

The heart far away/degree

(x)/nm (y)/nm absolute value/nm wavefront error

0 800 0 -0.340392 0.340392 0.0258308 0.017169

0 802 0 -0.548595 0.548595 0.0138699 0.019794

0 804 0 -0.199318 0.199318 0.00186948 0.024128

0 806 0 0.121535 0.121535 0.0101706 0.014148

0 808 0 -0.173787 0.173787 0.0222505 0.035190

12.5 800 0.0450163 -0.176646 0.182292 0.0264815 0.018897

12.5 802 -0.0866232 -0.387405 0.396971 0.0151773 0.020501

12.5 804 -0.0707759 -0.0498264 0.0865557 0.00674106 0.024709

12.5 806 0.0891365 0.250161 0.265567 0.0122229 0.015804

12.5 808 0.389682 -0.0752142 0.396874 0.0233473 0.036331

25 800 0.164298 0.201778 0.260208 0.0283526 0.021433

25 802 -0.143816 -0.0170961 0.144828 0.0185673 0.020512

25 804 -0.157147 0.284935 0.325397 0.0131056 0.024535

25 806 0.117459 0.521867 0.534922 0.0169632 0.017161

25 808 0.673133 0.105856 0.681406 0.0263743 0.038085

37.5 800 0.382136 0.456584 0.595397 0.0312476 0.023030

37.5 802 -0.192076 0.222698 0.294088 0.0231726 0.017658

37.5 804 -0.324591 0.463967 0.566237 0.0195923 0.021537

37.5 806 -0.025688 0.594265 0.59482 0.022802 0.014965

37.5 808 0.694325 0.0256282 0.694798 0.0307906 0.038495

50 800 0.623063 0.0244512 0.623543 0.0349462 0.032248

50 802 -0.351568 -0.233592 0.422096 0.0284496 0.023561

50 804 -0.738167 -0.0805832 0.742553 0.0261558 0.025133

50 806 -0.550452 -0.102823 0.559974 0.0291262 0.020735

50 808 0.197816 -0.888445 0.910201 0.0361232 0.042244

Figure 26 to 28 shows according to Figure 25, the lateral aberration in the coordinate system of the emergent pupil of object lens.

Figure 29 to 32 shows another embodiment of the present invention, and it has four catoptrons that are designed to the free type curved surface.Show object plane 3000, as plane 3002, the first catoptron S1, the second catoptron S2, the 3rd catoptron S3, the 4th catoptron S4.Below all, in the table of optical data, catoptron S1 is expressed as M1 to M4 to S4.For embodiment, provide following data according to Figure 29 to 32:

Numerical aperture: 0.24

The imaging factor: 1: 5

Thing field shape: rectangle

Thing side scanning field width: 100mm

Thing side scanning field height: 8mm

Length: 2273mm

Picture plane inclination: 0 °

Compare with the embodiment of Figure 25, this embodiment has low a little numerical aperture and high a little residual aberration, but according to Figure 17 system length.

Optical data can obtain from following table:

x _Thing/mmy _Thing/mmThe distortion distortion distorts 13,5nm's

The heart far away/degree

(x)/nm (y)/nm absolute value/nm wavefront error

0 600 0 -0.303712 0.303712 0.0350766 0.023748

0 602 0 -0.943417 0.943417 0.0190794 0.022355

0 604 0 -0.508069 0.508069 0.00301184 0.029861

0 606 0 0.00377447 0.003775 0.0131266 0.017655

0 608 0 -0.410098 0.410098 0.0293362 0.037546

12.5 600 -0.0976702 -0.0397139 0.105436 0.0359221 0.024194

12.5 602 -0.336727 -0.658804 0.73987 0.0208196 0.021336

12.5 604 -0.305426 -0.223582 0.378515 0.00938223 0.028592

12.5 606 -0.0115266 0.267305 0.267554 0.0161529 0.016575

12.5 608 0.537176 -0.188439 0.569269 0.0309678 0.038828

25 600 0.0740798 0.543069 0.548099 0.0383664 0.025529

25 602 -0.488733 -0.0159655 0.488994 0.0253625 0.019218

25 604 -0.511562 0.417058 0.660025 0.0180672 0.025576

25 606 -0.00993471 0.843229 0.843287 0.0229845 0.014322

25 608 1.00055 0.259991 1.03377 0.0354364 0.042367

37.5 600 0.635211 0.816881 1.03479 0.0421854 0.027832

37.5 602 -0.420855 0.35196 0.548629 0.0315907 0.018948

37.5 604 -0.668773 0.775246 1.02385 0.0269974 0.023314

37.5 606 -0.131864 1.08739 1.09535 0.0312902 0.013747

37.5 608 1.16644 0.285392 1.20085 0.0418989 0.047139

50 600 1.40779 -0.264954 1.43251 0.0471254 0.033617

50 602 -0.396014 -0.610703 0.727863 0.0387971 0.027129

50 604 -1.12571 -0.213831 1.14584 0.0360974 0.028277

50 606 -0.812445 -0.0743145 0.815836 0.0402623 0.020092

50 608 0.512487 -1.19576 1.30095 0.0496609 0.052034

Figure 30 to 32 shows according to Figure 29, the lateral aberration in the coordinate system of the emergent pupil of object lens.

Figure 33 to 36 shows another embodiment of the present invention, and it has four catoptrons that are designed to the free type curved surface.Show object plane 3000, as plane 3002, the first catoptron S1, the second catoptron S2, the 3rd catoptron S3, the 4th catoptron S4.Below all, in the table of optical data, catoptron S1 is expressed as M1 to M4 to S4.For embodiment, provide following data according to Figure 33 to 36:

Numerical aperture: 0.30

The imaging factor: 1: 5

Thing field shape: rectangle

Thing side scanning field width: 100mm

Thing side scanning field height: 8mm

Length: 2332mm

Picture plane inclination :-4.515 °

In this optical system, under the blocking of no optic part, realized very high numerical aperture.

Optical data can obtain from following table:

x _Thing/mmy _Thing/mmThe distortion distortion distorts 13,5nm's

The heart far away/degree

(x)/nm (y)/nm absolute value/nm wavefront error

0 600 0 -0.166318 0.166318 0.0148053 0.053501

0 602 0 -0.731572 0.731572 0.00884521 0.019284

0 604 0 -0.661487 0.661487 0.00282744 0.038268

0 606 0 -0.504836 0.504836 0.0032483 0.021472

0 608 0 -0.810627 0.810627 0.00938234 0.047628

12.5 600 -0.852921 0.132616 0.863169 0.0186158 0.052338

12.5 602 -0.193958 -0.398416 0.44312 0.0145478 0.024553

12.5 604 0.181685 -0.303572 0.353787 0.0121468 0.042437

12.5 606 0.270096 -0.131573 0.300439 0.012504 0.02662

12.5 608 0.0673771 -0.431381 0.436611 0.0154976 0.048115

25 600 -1.29433 0.754312 1.49809 0.0270423 0.048536

25 602 -0.101019 0.323398 0.338808 0.0247903 0.031643

25 604 0.524636 0.489914 0.717815 0.0238524 0.049015

25 606 0.574789 0.705289 0.909844 0.0244236 0.033313

25 608 0.0416169 0.420711 0.422764 0.0264463 0.04856

37.5 600 -1.11433 0.871449 1.41462 0.0371683 0.044918

37.5 602 0.363273 0.598909 0.700471 0.0359881 0.032203

37.5 604 0.986834 0.876191 1.31968 0.0357827 0.049123

37.5 606 0.744538 1.15498 1.37416 0.0365972 0.031801

37.5 608 -0.375406 0.886699 0.962894 0.0383944 0.049913

50 600 -0.505166 -0.901506 1.03339 0.0480691 0.060875

50 602 0.879494 -0.970155 1.30947 0.0476135 0.036681

50 604 1.12068 -0.556047 1.25104 0.0479137 0.044354

50 606 0.202525 -0.20714 0.289695 0.0489775 0.03033

Figure 34 to 36 has gone out according to Figure 33, the lateral aberration in the coordinate system of the emergent pupil of object lens.

Figure 37 to 40 shows another embodiment of the present invention, and it has four catoptrons that are designed to the free type curved surface.Show object plane 3000, as plane 3002, the first catoptron S1, the second catoptron S2, the 3rd catoptron S3, the 4th catoptron S4.Below all, have in the table of optical data, catoptron S1 is expressed as M1 to M4 to S4.For embodiment, provide following data according to Figure 37 to 40:

Numerical aperture: 0.20

The imaging factor: 1: 4

Thing field shape: rectangle

Thing side scanning field width: 100mm

Thing side scanning field height: 8mm

Length: 2084mm

Picture plane inclination :+6.890 °

This embodiment shows catoptron and arranges, and wherein has the high chief ray angle with respect to the object plane normal.This helps unshowned light path and the separation between the imaging path on reflection mask or the chopper wheel.And in this embodiment, the incident maximum angle on the minute surface is lower, helps the manufacturing of reflection multilayer structure.

Optical data can obtain from following table:

x _Thing/mmy _Thing/mmThe distortion distortion distorts 13,5nm's

The heart far away/degree

(x)/nm (y)/nm absolute value/nm wavefront error

0 800 0 -0.366434 0.366434 0.0198854 0.093978

0 802 0 -0.0892875 0.0892875 0.0104067 0.015958

0 804 0 -0.0777646 0.0777646 0.0009187 0.032744

0 806 0 0.0405964 0.0405964 0.0085785 0.042489

0 808 0 0.661542 0.661542 0.018085 0.028159

12.5 800 0.0955838 -0.353342 0.366042 0.0306806 0.091554

12.5 802 -0.0573173 -0.0687788 0.089531 0.0256084 0.020828

12.5 804 -0.106637 -0.0760641 0.130985 0.0234513 0.03637

12.5 806 -0.0613664 -0.00241775 0.061414 0.0249869 0.044044

12.5 808 0.0696061 0.548237 0.552638 0.0296558 0.030805

25 800 0.115633 -0.279658 0.302621 0.0507857 0.08257

25 802 -0.184329 0.0221776 0.185658 0.047943 0.024249

25 804 -0.278855 -0.0466988 0.282738 0.0468785 0.040154

25 806 -0.1860 -0.112547 0.2174 0.0477167 0.043512

25 808 0.0763955 0.221706 0.234499 0.050368 0.032565

37.5 800 0.146594 -0.0521759 0.155602 0.072869 0.065923

37.5 802 -0.292306 0.261705 0.392342 0.0709743 0.020204

37.5 804 -0.42743 0.0728035 0.433586 0.0703175 0.037534

37.5 806 -0.286029 -0.243519 0.375651 0.0709367 0.034303

37.5 808 0.104968 -0.288511 0.307012 0.0728031 0.030384

50 800 0.555156 0.451152 0.715358 0.095576 0.062457

50 802 -0.0193915 0.746217 0.746469 0.0941997 0.044595

50 804 -0.197219 0.352291 0.403738 0.0937666 0.049527

50 806 -0.0149766 -0.352951 0.353268 0.0942927 0.040292

50 808 0.491125 -0.968364 1.08579 0.0957648 0.053486

Figure 38 to 40 shows according to Figure 37, the lateral aberration in the coordinate system of the emergent pupil of object lens.

Figure 41 to 44 shows another embodiment of the present invention, and it has four catoptrons that are designed to the free type curved surface.Show object plane 3000, as plane 3002, the first catoptron S1, the second catoptron S2, the 3rd catoptron S3, the 4th catoptron S4.Below all, have in the table of optical data, catoptron S1 is expressed as M1 to M4 to S4.For embodiment, provide following data according to Figure 41 to 44:

Numerical aperture: 0.22

The imaging factor: 1: 4

Thing field shape: rectangle

Thing side scanning field width: 100mm

Thing side scanning field height: 6mm

Length: 1610mm

Picture plane inclination :-3.269 °

This optical system has the whole thing field width degree of 100mm, and combination high-NA and significantly be lower than the length of 2m.

Optical data can obtain from following table:

x _Thing/mmy _Thing/mmThe distortion distortion distorts 13,5nm's

The heart far away/degree

(x)/nm (y)/nm absolute value/nm wavefront error

0 400 0 -1.00949 1.00949 0.0229582 0.016806

0 401.5 0 -1.95078 1.95078 0.0133671 0.014259

0 403 0 -1.62222 1.62222 0.00369148 0.023621

0 404.5 0 -1.10626 1.10626 0.00606921 0.019377

0 406 0 -1.48681 1.48681 0.0159156 0.012538

12.5 400 -0.880918 -0.237177 0.912288 0.0242612 0.029659

12.5 401.5 -0.966915 -1.11354 1.47475 0.0158373 0.024479

12.5 403 -0.748886 -0.752973 1.06198 0.00983379 0.029615

12.5 404.5 -0.234325 -0.238253 0.334175 0.0114533 0.0278

12.5 406 0.569207 -0.653615 0.866723 0.0189539 0.028612

25 400 -0.712509 1.51156 1.67107 0.0278372 0.041582

25 401.5 -1.05587 0.817705 1.33548 0.0216593 0.031971

25 403 -0.794449 1.26023 1.48974 0.0186545 0.033731

25 404.5 0.0563116 1.75538 1.75628 0.0204067 0.035112

25 406 1.48083 1.21794 1.91735 0.0260668 0.043885

37.5 400 0.775815 2.32893 2.45475 0.0330354 0.035552

37.5 401.5 -0.220665 1.89815 1.91094 0.0289732 0.019017

37.5 403 -0.318211 2.43041 2.45116 0.0278179 0.018555

37.5 404.5 0.458907 2.84034 2.87718 0.0299911 0.023281

37.5 406 2.08622 2.04109 2.91862 0.0349482 0.041572

50 400 2.20545 -1.61745 2.73499 0.0393365 0.049861

50 401.5 -0.163904 -1.76675 1.77434 0.0370418 0.045563

50 403 -1.35027 -1.20714 1.81119 0.0372211 0.042817

50 404.5 -1.38792 -1.02622 1.72611 0.0399036 0.036919

50 406 -0.3114 -2.31311 2.33398 0.0446971 0.041068

Figure 42 to 44 shows according to Figure 41, the lateral aberration in the coordinate system of the emergent pupil of object lens.

Figure 45 to 48 shows another embodiment of the present invention, and it has four catoptrons that are designed to the free type curved surface.Show object plane 3000, as plane 3002, the first catoptron S1, the second catoptron S2, the 3rd catoptron S3, the 4th catoptron S4.Below all, have in the table of optical data, catoptron S1 is expressed as M1 to M4 to S4.For embodiment, provide following data according to Figure 45 to 48:

Numerical aperture: 0.2

The imaging factor: 1: 4

Thing field shape: rectangle

Thing side scanning field width: 48mm

Thing side scanning field height: 6mm

Length: 805mm

Picture plane inclination :-3.254 °

Owing to have less thing field, this optical system is very compact.

Optical data can obtain from following table:

x _Thing/mmy _Thing/mmThe distortion distortion distorts 13,5nm's

The heart far away/degree

(x)/nm (y)/nm absolute value/nm wavefront error

0 200 0 0.448311 0.448311 0.0429146 0.030026

0 201.5 0 -2.47405 2.47405 0.0235631 0.014465

0 203 0 -0.967497 0.967497 0.00387066 0.028481

0 204.5 0 0.932079 0.932079 0.0161673 0.017921

0 206 0 -0.816331 0.816331 0.0365555 0.020854

6 200 -0.229332 0.72028 0.755908 0.0429896 0.031915

6 201.5 -0.764827 -2.11395 2.24805 0.0241369 0.015911

6 203 -0.727117 -0.578603 0.929236 0.00803243 0.028531

6 204.5 -0.144224 1.28903 1.29708 0.018286 0.019129

6 206 0.955191 -0.553491 1.10397 0.0378693 0.025583

12 200 0.0887838 1.34107 1.34401 0.0432387 0.034302

12 201.5 -1.10902 -1.23729 1.66157 0.0258287 0.016652

12 203 -1.16563 0.372291 1.22364 0.0146925 0.027176

12 204.5 -0.139014 2.12835 2.13289 0.0235883 0.019707

12 206 1.91157 -0.015856 1.91164 0.0416026 0.033254

18 200 1.27353 1.60761 2.05092 0.0437339 0.03238

18 201.5 -0.903733 -0.573284 1.07023 0.0285705 0.014127

18 203 -1.38256 1.11952 1.77898 0.0218489 0.02358

18 204.5 -0.254443 2.63758 2.64983 0.0306063 0.015334

18 206 2.38718 -0.072959 2.38829 0.0472927 0.036701

24 200 3.13573 -0.027319 3.13585 0.0445949 0.032197

24 201.5 -0.646294 -1.71453 1.8323 0.0322942 0.028012

24 203 -2.18957 0.0094815 2.18959 0.0293844 0.032097

24 204.5 -1.62383 1.08662 1.95386 0.0386179 0.018853

24 206 0.918622 -2.54687 2.70747 0.0544894 0.035386

Figure 46 to 48 shows according to Figure 45, the lateral aberration in the coordinate system of the emergent pupil of object lens.

All show optical system at all embodiment shown in Figure 17 to 52 with rectangle thing field.

Figure 49 to 50 shows another embodiment of the present invention, and it has four catoptrons that are designed to the free type curved surface.Show object plane 3000, as plane 3002, the first catoptron S1, the second catoptron S2, the 3rd catoptron S3, the 4th catoptron S4.Below all, have in the table of optical data, catoptron S1 is expressed as M1 to M4 to S4.For embodiment, provide following data according to Figure 49 to 50:

Numerical aperture: 0.22

The imaging factor: 1: 4

Thing field shape: radius is the ring section of 600mm, position angle-4.8 °＜φ＜+4.8 °

Thing side scanning field width: 100mm

Thing side scanning field height: 8mm

Length: 2418mm

Picture plane inclination :-3.284 °

This embodiment shows described design advantage and also is suitable for for the optical system with non-rectangle thing field.

Optical data can obtain from following table:

x _Thing/mmy _Thing/mmThe distortion distortion distorts 13,5nm's

The heart far away/degree

(x)/nm (y)/nm absolute value/nm

Wavefront error

0 600 0 -0.892917 0.892917 0.0133679 0.012256

0 602 0 -0.841667 0.841667 0.00534092 0.016933

0 604 0 0.0201694 0.0201694 0.00275272 0.021805

0 606 0 0.379474 0.379474 0.0109134 0.010404

0 608 0 -1.08242 1.08242 0.0191416 0.02706

12.5655 599.868 -0.463563 -0.551102 0.720142 0.0164908 0.01867

12.6073 601.868 -0.477332 -0.590644 0.759412 0.0108284 0.018161

12.6492 603.868 -0.257454 0.245037 0.355423 0.0095748 0.022897

12.6911 605.867 0.191813 0.643426 0.671409 0.0140875 0.014667

12.733 607.867 0.866074 -0.713531 1.12215 0.0209974 0.029184

25.1254 599.474 -0.531595 0.291324 0.606187 0.0234981 0.028751

25.2091 601.472 -0.737092 -0.0428674 0.738337 0.0195942 0.018248

25.2929 603.47 -0.47659 0.691569 0.839884 0.0185603 0.0228

25.3766 605.468 0.241321 1.18393 1.20828 0.0209057 0.018522

25.4604 607.467 1.40777 0.117965 1.4127 0.0257861 0.030662

37.6743 598.816 0.166072 1.07231 1.08509 0.0319492 0.037305

37.7999 600.812 -0.597255 0.172817 0.621755 0.0288103 0.012352

37.9255 602.808 -0.665059 0.662666 0.938845 0.0277044 0.017593

38.0511 604.804 -0.0504098 1.23414 1.23517 0.0289218 0.01636

38.1766 606.8 1.23319 0.573939 1.36021 0.0322511 0.025322

50.2067 597.896 1.97056 0.813316 2.13181 0.0409886 0.048287

50.3741 599.889 0.0758373 -1.03335 1.03613 0.0381837 0.020354

50.5414 601.882 -0.898661 -1.045 1.37827 0.0369235 0.027327

50.7088 603.875 -0.970685 -0.525246 1.10368 0.0374078 0.03097

50.8761 605.868 -0.159467 -1.30833 1.31801 0.0398057 0.030446

Figure 50 shows according to Figure 49, the lateral aberration in the coordinate system of the emergent pupil of object lens.

Figure 51 shows another embodiment of the present invention, and it has six catoptrons that are designed to the free type curved surface.Show object plane 3000, as plane 3002, first mirror M 1, second mirror M 2, the 3rd mirror M 3, the 4th mirror M 4, the 5th mirror M 5 and the 6th mirror M 6.This projection objective has 0.40 picture side numerical aperture.The field is shaped as rectangle, and its width is 26mm, highly is 2mm.Operation wavelength is 13.5nm.The catoptron focal power is PNPNNP successively.This optical system has the intermediary image between mirror M 4 and M5.The entrance pupil of this projection objective is positioned at the 1000mm place apart from object plane 3000, and object plane is between entrance pupil and catoptron.Track lenth is 1736mm, and the image skew is 65mm.Optical path length is 4827mm.

The performance of this projection objective comprises the picture side W of 0.037 λ _RmsDistortion is less than 12nm.As the side field curvature is 25nm.

The chief ray angle of central field point is 7 ° on the object plane.The maximum variable quantity of chief ray angle is 0.82 ° on the object plane.

The size of the occupy-place face of each catoptron is given as M _x* M _y, as follows: mirror M 1 is 323mm * 215mm, and mirror M 2 is 131mm * 102mm, and mirror M 3 is 267mm * 183mm, and mirror M 4 is 70mm * 52mm, and mirror M 5 is 124mm * 109mm, and mirror M 6 is 447mm * 433mm.

For mirror M 1 to M6, the incident chief ray angle of central field point is 4.06 °, 11.34 °, 12.20 °, 31.60 °, 12.27 ° and 7.64 °.For mirror M 1 to M6, the maximum incident angle degree θ on the meridian cross section _MaxIt is 4.96 °, 12.38 °, 16.54 °, 41.24 °, 29.42 ° and 9.25 °.For mirror M 1 to M6, the incident angle bandwidth of meridian ellipse is 1.08 °, 2.71 °, 9.83 °, 22.72 °, 29.13 ° and 4.28 °.Mirror M 2 and M4 have greater than 5mm and less than the freeboard of 25mm.Mirror M 3 has positive chief ray angle magnification, and mirror M 1, M2, M4 and M5 have negative chief ray angle magnification.

This projection objective be 45mm as the free operating distance of side.The free operating distance of thing side is 400mm.

In this projection objective, d _Op-1/ d _Op-2Be 2.67.And, chopper wheel and mirror M 1, and mirror M 2 and M3 are separated by the projection objective track lenth greater than 50%.

Shown in the related data of the projection objective of Figure 51 table 8A below and the table 8B.Table 8A shows optical data, and table 8B shows the aspheric surface constant of each mirror surface.

Table 8A

Table 8B

The projection objective of Figure 51 is different from the shape that Fig. 3,10,11,12,13,14 and 15 embodiment part mainly are mirror M 4.Compare with these previously described embodiment, the mirror M 4 of the embodiment of Figure 51 is convex surfaces.

Figure 52 shows another embodiment of the present invention, and it has six catoptrons that are designed to the free type curved surface.Show object plane 3000, as plane 3002, first mirror M 1, second mirror M 2, the 3rd mirror M 3, the 4th mirror M 4, the 5th mirror M 5 and the 6th mirror M 6.This projection objective has 0.35 picture side numerical aperture.The field is shaped as rectangle, its wide 26mm, high 2mm.Operation wavelength is 13.5nm.The catoptron focal power is PPNPNP successively.This optical system has an intermediary image between mirror M 4 and M5.The entrance pupil of this projection objective is positioned at picture plane one side of object plane 3000 with the distance of 1749mm.Aperture diaphragm is positioned on the mirror M 2.Track lenth is 1700mm, and the image skew is 41mm.Optical path length is 4156mm.

The performance of this projection objective comprises the picture side W of 0.020 λ _RmsDistortion is less than 1.1nm.As the side field curvature is 17nm.

The chief ray angle of central field point is 6 ° on the object plane.The maximum variable quantity of chief ray angle is 0.58 ° on the object plane 3000.

The size of the occupy-place face of each catoptron is given as M _x* M _y, as follows: mirror M 1 is 169mm * 148mm, and mirror M 2 is 159mm * 136mm, and mirror M 3 is 120mm * 61mm, and mirror M 4 is 265mm * 118mm, and mirror M 5 is 101mm * 77mm, and mirror M 6 is 345mm * 329mm.

For mirror M 1 to M6, the incident chief ray angle of central field point is 8.11 °, 9.49 °, 21.03 °, 8.01 °, 13.67 ° and 5.03 °.For mirror M 1 to M6, the maximum incident angle degree θ on the meridian cross section _MaxIt is 10.31 °, 12.06 °, 21.56 °, 8.45 °, 24.59 ° and 6.36 °.For mirror M 1 to M6, the incident angle bandwidth in meridian cross section is 4.56 °, 5.34 °, 1.85 °, 1.23 °, 22.98 ° and 3.16 °.Mirror M 4 has positive chief ray angle magnification, and mirror M 1, M2, M3 and M5 have negative chief ray angle magnification.

This projection objective be 45mm as the free operating distance of side.The free operating distance of thing side is 441mm.

In this projection objective, d _Op-1/ d _Op-2Be 1.89.And mirror M 4 and M5 are separated by the projection objective track lenth greater than 50%.

Shown in the related data of the projection objective of Figure 52 table 9A below and the table 9B.Table 9A shows optical data, and table 9B shows the aspheric surface constant of each mirror surface.

Table 9A

Table 9B

The chief ray of the projection objective among Figure 52 converges after object plane 3000 penetrates each other.

The micro-lithography instrument, for example the micro-lithography instrument 100 of describing and illustrating among Fig. 1 in the above can be used in the manufacturing of semiconductor device, for example semi-conductor chip, panel of LCD (LCD) or charge-coupled device (CCD) (CCD) array detector.Usually, in making semiconductor device, the order of procedure of processing is variable according to the concrete device of making.Figure 53 shows the process flow diagram of making the sequence of steps example in the semiconductor device.Beginning, in step 5310, producer designs is used for the integrated circuit that will make of semiconductor device.Then, in step 5320, according to the design generation mask (for example, chopper wheel) of integrated circuit.Before reality generates integrated circuit, shown in step 5330, prepare wafer (for example, Silicon Wafer).Next step in wafer-process step (step 5340), utilizes mask to form integrated circuit on wafer.The details of wafer-process will discuss in more detail below.After forming integrated circuit on the wafer, cutting, welding and encapsulation wafer are to make independently microchip (step 5350).These installation step are commonly referred to aftertreatment.After assembling, check chip (step 5360).For example, operability and/or persistence that can test chip.By checking that step 5360 device is transported subsequently to the user (step 5370).

Figure 54 shows the process flow diagram of wafer-process step details.Usually, wafer-process comprises, forms the layer (for example, conductive material, semiconductor material and/or dielectric material) (step 5410) of a plurality of different materials on wafer.Utilize one or more (step 5420) in these layers of photoetching process composition.These layer formation that can in all sorts of ways.For example, forming described layer can comprise: the surface of oxidation wafer in oxidation procedure of processing (step 5411).In certain embodiments, form described layer and comprise, for example by chemical vapor deposition (CVD), at the surface deposition material (step 5412) of wafer.In a particular embodiment, form described layer and comprise the electrode formation technology (step 5412) that for example on wafer, forms electrode by vapour deposition.Form described layer and can comprise the ion implantation technology (step 5414) that is used for wafer is injected ion.

After forming material layer, can use the described layer of photoetching process composition.This generally includes the process against corrosion (step 5415) that wafer is applied resist.Step 5416 is exposure process, and it utilizes lithography tool by exposure, and for example above-mentioned lithography tool 100 is printed onto the circuitous pattern of mask on the wafer.Step 5417 is developing processs, wherein the resist that develops and exposed.After developing, in etch processes, etching is by the part (step 5418) of the wafer of the resist exposure of development.At last, in the resist separating treatment, remaining anticorrosive additive material is removed (step 5419) from wafer.

Repeating

step

5410 and 5420, thus integrated circuit on wafer, formed.Embodiment can comprise other treatment steps, for example, carries out polishing wafer before or after composition on the material layer.

Other embodiment are included in the claim.

Claims

1. micro-lithography projection optical system comprises:

A plurality of elements, its be set to the wavelength from object plane be λ photoimaging to the picture plane, at least one described element is a reflecting element, it has the rotation asymmetric surface that is positioned on the light path,

Wherein, at least one position, described rotation asymmetric surface departs from λ at least from best-fit rotation symmetrical surface.

2. according to the optical system of claim 1, wherein, described best-fit rotation asymmetric surface is less than or equal to about 0.1 λ from departing from corresponding to the surface of following formula:

z = \frac{{cr}^{2}}{1 + \sqrt{1 - (1 + k) c^{2} r^{2}}} + Σ_{j = 2}^{α} C_{j} x^{m} y^{n}

Wherein

j = \frac{{(m + n)}^{2} + m + 3 n}{2} + 1,

Z is the sag that is parallel to the surface of axle, and c is a vertex curvature, and k is the cone constant, C _jBe monomial x ^my ⁿCoefficient, and α is an integer.

3. according to the optical system of claim 1, wherein, in one or more positions, described rotation asymmetric surface departs from more than or equal to about 10 λ from described best-fit rotation symmetrical surface.

4. according to the optical system of claim 1, wherein, in one or more positions, described rotation asymmetric surface departs from more than or equal to about 20nm from described best-fit rotation symmetrical surface.

5. according to the optical system of claim 1, wherein, described a plurality of elements define meridian ellipses, and described element is the minute surface symmetry with respect to described meridian ellipse.

6. according to the optical system of claim 1, wherein, described a plurality of elements comprise two reflecting elements, and described reflecting element has the rotation asymmetric surface that is positioned on the light path.

7. according to the optical system of claim 1, wherein, described a plurality of elements comprise and are no more than two reflecting element that described reflecting element has positive chief ray angle magnification.

8. according to the optical system of claim 7, wherein, described a plurality of elements comprise and are no more than one reflecting element that described reflecting element has positive chief ray angle magnification.

9. according to the optical system of claim 1, wherein, described micro-lithography projection optical system has the picture side numerical aperture more than or equal to about 0.2.

10. according to the optical system of claim 1, wherein, described optical system has rectangular field on as the plane, and, wherein, on each direction of orthogonal directions, described rectangular field all has the minimum dimension more than or equal to about 1mm on orthogonal both direction.

11. according to the optical system of claim 1, wherein, the static state at described image field place distorts to being less than or equal to about 10nm.

12. according to the optical system of claim 1, wherein, the wavefront error at described image field place is to be less than or equal to about λ/14.

13. according to the optical system of claim 1, wherein, described chief ray is dispersed on object plane each other.

14. according to the optical system of claim 13, wherein, for the meridian cross section of described optical system, the maximum incident angle of described chief ray on each described element surface is less than 20 °.

15. according to the optical system of claim 1, its described be the heart far away as the plane.

16. optical system according to claim 1, wherein, light path by described optical system can characterize with chief ray, and, meridian cross section for described optical system, the chief ray of central field point has the maximum incident angle of θ degree on each described element surface, described optical system has the picture side numerical aperture NA greater than 0.3, and ratio θ/NA is less than 68.

17. according to the optical system of claim 1, wherein, described optical system has the image skew that is less than or equal to about 75mm.

18. according to the optical system of claim 1, wherein, described a plurality of elements comprise the element more than or equal to four, it has the freeboard that is less than or equal to about 25mm.

19. according to the optical system of claim 1, also comprise light source, it is configured to provide wavelength to object plane is the light of λ.

20. optical system according to claim 19, also comprise irradiation system, it comprises one or more elements, described element is set to, to be directed to the thing that is positioned at the object plane place from the light of light source, wherein, described irradiation system comprises the element that is positioned at corresponding to the position of the entrance pupil of optical system.

21. a micro-lithography instrument comprises:

Optical system according to claim 20;

First objective table movably, it is configured to locate the chopper wheel on the object plane, so that described optical system is imaged onto the picture plane with described chopper wheel; And

Second objective table movably, it is configured to locate the object as on the plane, so that the image position of described chopper wheel is in the surface of described object.

22. one kind is used for the method that micro-lithography is made micro-structural components, may further comprise the steps:

Provide and have the substrate of one deck photochromics at least;

Mask with the structure that will be projected is provided;

Micro-lithography instrument according to claim 21 is provided;

Use described micro-lithography instrument, described mask projected to the zone of described layer to small part.

23. a micro-structural components, it is by the method manufacturing according to claim 22.

24. the method for the rotation asymmetric surface in the optical system of one of design consideration claim 1 to 20 may further comprise the steps:

From with respect to the rotational symmetric design of light path;

By being parallel to the axle that limits by light path with respect to the described rotation axes of symmetry of this optical path axis translation, and eccentric described rotation symmetric design;

By the described rotation axes of symmetry that tilts with respect to described optical path axis, and the described rotation symmetric design that tilts;

Depart from by carrying out free type from the design of described off-centre and inclination, and the minimum optical aberration.