CN100409045C - Polarization conversion element, lighting optical device, exposure system, and exposure method - Google Patents

Abstract

A polarization conversion element capable of converting, with a limited light quantity loss, a linearly polarized incident light having a polarization direction in an almost single direction into a circumferentially polarized light having a polarization direction in an almost circumferential direction. A polarization conversion element (10) for converting the polarization state of an incident light into a specified polarization state. It is formed of an optical material having optical rotation, for example, quartz, and has a thickness distribution changing in a circumferential direction. The thickness distribution is so set that a linearly polarized light having a polarization direction in an almost single direction is converted into a circumferentially polarized light having a polarization direction in an almost circumferential direction. It has a plurality of circumferentially divided areas (10A-10D), and two arbitrary adjacent areas in the plurality of areas are different in thickness from each other. Also, two arbitrary facing areas in the plurality of areas have optical rotation angles almost equal to each other.

Description

Polarization conversion element, illumination optical apparatus, exposure device and exposure method

Technical field

The invention relates to polarization conversion element, illumination optical apparatus, exposure device and exposure method, and, be used for making the micro-photographing process of the first-class microcomponent of semiconductor element, image capturing element, liquid crystal display cells, thin film magnetic particularly relevant for a kind of exposure device.

Background technology

About some typical exposure devices, the light beam that penetrates from light source is by compound eye (fly eye) lens as optical integrator (optical integrator), to form the secondary souce by the material surface light source that a plurality of light source was constituted.Light beam by secondary souce (generally being that the illumination pupil of illumination optical apparatus or near the illumination pupil that is formed on it distribute) penetrates after being limited, is incident in light collecting lens by near the aperture the rear side focus face that is configured in fly's-eye lens.

Utilize light collecting lens and by the light beam of light harvesting, and be formed the ground illumination that overlaps of the cover curtain of deciding pattern to some extent.Pass the light of the pattern of cover curtain, image on the wafer by projection optical system.Then, on wafer, cover curtain pattern is projected exposure (transfer printing).Again, be formed on the pattern of cover curtain, by high productive set the time, will correctly be transferred on the wafer for this fine pattern, it is indispensable will obtaining the homogeneous Illumination Distribution on wafer.

For example at No. 3246615 open source information of Jap.P. of inventor, announcement is in order to realize the fine pattern of any direction lighting condition with transfer printing verily, form the secondary souce of wheel belt shape at the rear side focus face of fly's-eye lens, and setting and to make the light beam that passes this wheel belt shape secondary souce, is linear polarization state (being designated hereinafter simply as " Zhou Fangxiang polarized condition ") at the polarization direction of Zhou Fangxiang.

But the technology of above-mentioned open source information is utilized by the formed circular light beam of fly's-eye lens, and restriction has the aperture of wheel belt shape opening, to form the wheel belt shape secondary souce.This result for conventional art, can make aperture produce a large amount of light losses, and then make the production capacity of exposure device low, therefore is not suitable for.

Summary of the invention

Because aforesaid problem, the present invention proposes a kind of polarization conversion element, can will the incident light of the linear polarization state of the polarization direction that is about single direction be arranged, be transformed into the light of the Zhou Fangxiang polarized condition of the polarization direction that is about Zhou Fangxiang, and can prevent light loss.

Again, the purpose of this invention is to provide illumination optical apparatus, use polarization conversion element, can will the incident light of the linear polarization state of the polarization direction that is about single direction be arranged, be transformed into the light of the Zhou Fangxiang polarized condition of the polarization direction that is about Zhou Fangxiang, can well prevent light loss, the wheel belt shape illumination pupil that forms the Zhou Fangxiang polarized condition distributes.

Again, the invention provides exposure device and exposure method, use illumination optical apparatus can well prevent light loss, the wheel belt shape illumination pupil that forms the Zhou Fangxiang polarized condition distributes, and uses the appropriate illumination condition, can be with fine pattern verily and the high yield transferability.

In order to solve foregoing problems, the first embodiment of the present invention provides a kind of polarization conversion element, be configured in the illumination path of illumination optical apparatus, described illumination optical apparatus is based on the light of linear polarization state and plane of illumination is thrown light on, and described linear polarization state only come from the light source that linear polarization is provided, behind the described polarization conversion element of light incident of described linear polarization state, described polarization conversion element penetrates the light that has the Zhou Fangxiang polarized condition of polarization direction at Zhou Fangxiang, or the light that has the footpath direction polarized condition of polarization direction in the footpath direction, this polarization conversion element utilizes active optical material, to be formed on Zhou Fangxiang thickness variation profile is arranged; And the polarization direction of the linear polarization of incident is rotated.

According to second embodiment of the invention, an illumination optical apparatus is provided, comprise the light source that illumination light is provided, and the light path between this light source and the plane of illumination is configured the polarization conversion element of first embodiment.

In third embodiment of the invention, illumination optical apparatus is provided, for according to the illumination light of supplying with by light source, throw light in the illumination optical apparatus of plane of illumination,

The illumination pupil face of aforementioned illumination optical apparatus or with the face of this illumination pupil face conjugation in the light intensity distributions that is formed, about its average specific polarizing coefficient of the 1st direction polarisation in fixed efficient light sources zone with RSP _h(Ave) expression, about the average specific polarizing coefficient of the 2nd direction polarisation with RSP _v(Ave) expression is satisfied

RSP _h(Ave)＞70％，RSP _v(Ave)＞70％。

Again,

RSP _h(Ave)＝Ix(Ave)/(Ix+Iy)Ave；

RSP _v(Ave)＝Iy(Ave)/(Ix+Iy)Ave。

In this, Ix (Ave) is by passing through any light beam that fixed efficient light sources zone arrives image planes, and is average in the intensity of the 1st direction polarized component.Iy (Ave) is by passing through any light beam that fixed efficient light sources zone arrives image planes, and is average in the intensity of the 2nd direction polarized component.(Ix+Iy) Ave is average by the intensity of whole beam intensities of passing through fixed efficient light sources zone.Again, the illumination pupil face of aforementioned illumination optical apparatus, be defined as the face of the optical Fourier transformational relation of corresponding aforementioned plane of illumination, in the situation of aforementioned illumination optical apparatus and projection optical system combination, can define the face in the illumination optical apparatus with the aperture optical conjugate of projection optical system.Again, with the face of the illumination pupil face conjugation of aforementioned illumination optical apparatus, be not limited to the face in the aforementioned illumination optical apparatus, for example aforementioned illumination optical apparatus also can the interior face of projection optical system during with the projection optical system combination.It more also can be the interior face of polarimetry device in order to the polarized condition that detects illumination optical apparatus (or projection aligner).

Fourth embodiment of the invention provides exposure device, comprises the illumination optical apparatus of second embodiment or the 3rd embodiment, pass this illumination optical apparatus will cover the curtain on pattern exposure on the photonasty substrate.

Fifth embodiment of the invention provides exposure method, uses the illumination optical apparatus of second embodiment or the 3rd embodiment, with the pattern exposure on the cover curtain on the photonasty substrate.

Sixth embodiment of the invention, a kind of method of making polarization conversion element is provided, be that linear polarization state transformation Cheng Zaizhou direction with incident light has the Zhou Fangxiang polarized condition of change state or has the manufacture method of polarization conversion element of the footpath direction change state of polarization direction in the footpath direction, it comprises: prepare active optical material; And set the thickness distribution that this optical material changes at Zhou Fangxiang.

Polarization conversion element of the present invention for example utilizes the optical material just like quartzy optical activity to be formed, in the Zhou Fangxiang thickness distribution that changes.In this, thickness distribution for example, is set the light of the linear polarization state that makes the polarization direction that is about single direction, is transformed into the light of the Zhou Fangxiang polarized condition of the polarization direction that is about Zhou Fangxiang.Its result in the present invention, can realize preventing light loss, and the incident light of the linear polarization state of the polarization direction that is about single direction will be arranged, and is transformed into the polarisation converting means of light of the Zhou Fangxiang polarized condition of the polarization direction that is about Zhou Fangxiang.Particularly, because utilize active optical material with formation polarisation converting means, and then the advantage that has wavelength plate on relatively, to be easy to make.

In addition, in illumination optical apparatus of the present invention, because use the polarisation converting means, can the incident light of linear polarization state of the polarization direction of single direction will be about, be transformed into the light of the Zhou Fangxiang polarized condition of the polarization direction that is about Zhou Fangxiang, can well prevent light loss, and form the wheel belt shape illumination pupil distribution of Zhou Fangxiang polarized condition.Again, exposure device of the present invention and exposure method, use illumination optical apparatus, can well prevent light loss, and the wheel belt shape illumination pupil that forms the Zhou Fangxiang polarized condition distributes, in the appropriate illumination condition, can loyal and high production capacity ground replicated fine pattern, and then the element manufacturing also has good production capacity.

For above-mentioned and other purposes, feature and advantage of the present invention can be become apparent, preferred embodiment cited below particularly, and cooperate appended graphicly, be described in detail below.

Description of drawings

Fig. 1 illustrates the exposure device structural representation according to the embodiment of the invention.

Fig. 2 illustrates relative wheel belt shape secondary souce, the Action Specification of circular cone prismatic mirror system.

Fig. 3 illustrates relative wheel belt shape secondary souce, the Action Specification of flexible lens.

Fig. 4 illustrates the inner structure signal oblique view of the polarisation monitor of Fig. 1.

Fig. 5 illustrates the inner structure synoptic diagram of the polarization conversion element of Fig. 1.

Fig. 6 illustrates quartzy optical activity key diagram.

Fig. 7 illustrates the effect that utilizes polarization conversion element, is configured to the wheel belt shape secondary souce synoptic diagram of Zhou Fangxiang polarized condition.

Fig. 8 illustrates the effect that utilizes polarization conversion element, is configured to the wheel belt shape secondary souce synoptic diagram of footpath direction polarized condition.

Fig. 9 illustrates the variation synoptic diagram that a plurality of polarization conversion elements can exchange.

Figure 10 illustrates turntable 10T as the exchange mechanism of Fig. 9 by the multiple polarization conversion element 10a of mounting～10e synoptic diagram.

Figure 11 A～11E illustrates multiple polarization conversion element 10a～10e and divides other structural representation.

Figure 12 A～12C illustrates the illustration intention that the effect that utilizes polarization conversion element is configured to the secondary souce of Zhou Fangxiang polarized condition.

Figure 13 illustrates the structural representation of the rotatable polarization conversion element 10f of optical axis AX that is arranged to unroll.

Figure 14 A～14C illustrates the effect that utilizes polarization conversion element 10f, is configured to the illustration intention of the secondary souce of Zhou Fangxiang polarized condition.

Figure 15 A～15C illustrates by 8 polarization conversion elements that fan-shaped basic building block constituted, the illustration intention of the rotatable secondary souce of optical axis AX that obtains unrolling.

Figure 16 illustrates polarization conversion element, is configured near the pupil of lamp optical system in the position, positive anterior locations (near the position light incident side) illustration of circular cone prismatic mirror system 8 is intended to.

Figure 17 illustrates variation example as shown in figure 16, is the explanation synoptic diagram of the formula of satisfying condition (1) with (2).

Figure 18 illustrates polarization conversion element, is configured near the pupil of lamp optical system in the position, position one illustration is intended near the pupil of imaging optical system 15.

Figure 19 illustrates the structural representation for the wafer face polarisation monitor 90 of the polarized condition of the light that detects illumination wafer W and light intensity.

Figure 20 illustrates and uses the 4 polarization conversion element 10f of cutting apart, and carries out 4 and cuts apart the illumination of Zhou Fangxiang polarisation wheel band, to obtain wheel belt shape secondary souce 31 synoptic diagram.

Figure 21 illustrates the actual processing procedure that obtains as the semiconductor element of microcomponent.

Figure 22 illustrates the actual processing procedure that obtains as the liquid crystal display cells of microcomponent.

1: light source 4: the polarized condition transformation component

4a:1/4 wavelength plate 4b:1/2 wavelength plate

4c: depolariser 5: diffractive optical elements

6: afocal lens 8: circular cone prismatic mirror system

9: flexible lens 10: polarization conversion element

10A～10D: each primary element 10E: central optical is by the zone

11: little fly's-eye lens 12: polarisation monitor

12a: optical splitter 13: light collection system

14: cover curtain shield 15: imaging optical system

104c: polarisation is cleared up the material M of portion: the cover curtain

PL: projection optical system W: wafer

Embodiment

Fig. 1 illustrates the exposure device synoptic diagram according to the embodiment of the invention.In Fig. 1, setting respectively along the photonasty substrate is that the normal direction of wafer W is the Z axle, and the direction parallel with the paper of Fig. 1 is Y-axis in the face of wafer W, and the interior direction vertical with the paper of Fig. 1 of the face of wafer W is X-axis.Please refer to Fig. 1, the exposure device of present embodiment comprises the light source 1 in order to the light (illumination light) of supplying with exposure.

As light source 1, for example can use the KrF quasi-molecule laser source of supplying with the 248nm wavelength light or the ArF quasi-molecule laser source of supplying with the 193nm wavelength light.The about parallel beam that penetrates from light source 1 along the Z direction has the rectangular-shaped section of elongated extension along directions X, and is incident in the optical beam expander 2 (expander) that is made of a pair of lens 2a and 2b.Each other lens 2a and 2b, (in the YZ plane) has negative refracting power and positive refracting power respectively in the paper of Fig. 1.Therefore, be incident in the light beam of optical beam expander 2, in the paper of Fig. 1, be exaggerated, and be shaped as the light beam of fixed to some extent rectangular cross section.

Pass about parallel light beam as the optical beam expander 2 of shaping optical system, after it is partial to the Y direction by catoptron 3 warpages, pass 1/4 wavelength plate 4a, 1/2 wavelength plate 4b, depolariser (depolarizer) 4c and wheel and be with illuminating diffractive optical elements 5, and be incident in no focus (afocal) lens 6.In this, 1/4 wavelength plate 4a, 1/2 wavelength plate 4b and depolariser 4c as described later, constitute polarized condition transformation component 4.No focus optical system is set at: make afocal lens 6, its focal position, front side is approximately consistent with the position of diffractive optical elements 5, and the rear side focal position is approximately consistent with the position of deciding face 7 as shown in phantom in FIG..

Generally, diffractive optical elements, substrate are formed with difference in height it are spaced apart light (illumination light) the wavelength degree of exposure, make incident beam in desired angle diffraction be arranged.Particularly, wheel is with illuminating diffractive optical elements 5, when to have section be rectangular-shaped parallel beam incident, has in the far field function that (far-field) (or Fraunhofer diffraction zone) forms the wheel belt shape light intensity distributions.

Therefore, be incident in the about parallel beam as the diffractive optical elements 5 of light beam conversion element, after the pupil face of afocal lens 6 formed the light intensity distributions of wheel belt shape, about parallel beam was penetrated from afocal lens 6.Near pupil face in the light path between the front lens group 6a of afocal lens 6 and the rear lens group 6b or its, be configured circular cone prismatic mirror (axicon) system 8, after its detailed structure and effect are described in again.Below, be simple declaration, ignore circular cone prismatic mirror system 8, basic structure and effect are described.

Pass the light beam of afocal lens 6, pass the flexible lens 9 (zoom lens) and polarization conversion element 10 of variable σ value usefulness, and be incident in little fly's-eye lens (or fly's-eye lens) 11 as optical integrator (opticalin tegrator).The structure of polarization conversion element 10 and Action Specification in after.Little fly's-eye lens 11 is by in length and breadth and a plurality of optical elements that micro lens constituted with positive refracting power of intensive assortment.Generally speaking, little fly's-eye lens for example is that to utilize planopaallel plate to apply etch processes made to form the micro lens group.

Then, constitute each micro lens of little fly's-eye lens, more small than each lens unit (lens element) that constitutes fly's-eye lens.Again, little fly's-eye lens, and by different by the isolated fly's-eye lens that lens unit constituted mutually, a plurality of micro lens (small flexion face) are not mutually by isolated and integrally formed.Yet on the viewpoint that the lens unit with positive refracting power is disposed in length and breadth, little fly's-eye lens is the optical integrator of the corrugated Splittable identical with fly's-eye lens.

Decide face 7 the position be configured in flexible lens 9 the focal position, front side near, and the plane of incidence of little fly's-eye lens 11 be configured in flexible lens 9 the rear side focal position near.In other words, flexible lens 9 are configured to the plane of incidence that institute decide face 7 and little fly's-eye lens 11 and are essentially fourier transform and concern, and then the plane of incidence that is configured to the pupil face of afocal lens 6 and little fly's-eye lens 11 is optical conjugate roughly.

Then, identical on the plane of incidence of little fly's-eye lens 11 with the pupil face of afocal lens 6, for example be formed the wheel belt shape range of exposures as the center with optical axis AX.All shapes of this wheel belt shape range of exposures are interdependent and similarly change with the focal length of the lens 9 that stretch.Each micro lens that constitutes little fly's-eye lens 11 has rectangular-shaped section, and it is similar to the shape that will form range of exposures on the cover curtain M shape of exposure area (and then will form on wafer W).

The light beam of the little fly's-eye lens 11 of incident is to utilize a plurality of micro lens and cut apart by two dimension, its rear side focus face or its neighbouring (and then illumination pupil), by incident beam, the secondary souce of the about same light intensity distributions of the range of exposures that has and be formed promptly is to be formed as the secondary souce that the material surface light source of the wheel belt shape at center is constituted with optical axis AX.From the rear side focus face of little fly's-eye lens 11 or near the light beam of the secondary souce that is formed it, pass optical splitter 12a (beam splitter) and light collection system 13 after, with a cover curtain shield (mask blind) the ground illumination that overlaps.

Then, the cover curtain shield 14 as illumination visual field aperture has formed rectangular-shaped range of exposures, its corresponding shape and focal length that constitutes each micro lens of little fly's-eye lens 11.Moreover inside is provided with the polarisation monitor 12 of optical splitter 12a, and its inner structure and effect are as described later.Pass the light beam of the rectangular-shaped peristome (transmittance section) of cover curtain shield 14, after the light harvesting effect that is subjected to imaging optical system 15, be radiated at formation with overlapping and decide to some extent on the cover curtain M of pattern.

Promptly be that imaging optical system 15 is formed on the cover curtain M picture of the rectangular-shaped peristome of cover curtain shield 14.Pass the light beam of the pattern of cover curtain M, pass projection optical system PL again, it is on the wafer W that the picture that covers the curtain pattern is formed at the photonasty substrate.Then, in the plane vertical with the optical axis AX of projection optical system PL (XY face), utilize two-dimensionally drive controlling wafer W to carry out all or scan exposure, the pattern of cover curtain M is exposed to each exposure area of wafer W in regular turn.

Again, in polarized condition switching part 4,1/4 wavelength plate 4a is configured and can rotates freely on the crystal optics axle as the center with optical axis AX, with the elliptical polarized light optical beam transformation of the incident light beam of polarized light that is in line.Again, 1/2 wavelength plate 4b is configured and can rotates freely on the crystal optics axle as the center with optical axis AX, and the plane of polarisation of the linear polarization of incident is changed.Again, depolariser 4c utilizes the quartzy prism of the wedge shape that complementary shape is arranged and wedge shape quartz prism and is configured.Quartzy prism and quartz prism be as the prism assembly of one, is configured can freely insert illumination path to take off.

Use under KrF quasi-molecule laser source or the situation of ArF quasi-molecule laser source as light source 1, the light from these light sources are penetrated generally has the degree of polarization more than 95%, and the light of about linear polarization is incident in 1/4 wavelength plate 4a.But, in the light path between light source 1 and the polarized condition switching part 4, when the situation as the right-angle prism of back reflector was arranged, the plane of polarisation of the linear polarization of incident was not consistent with P plane of polarisation or S plane of polarisation, utilizes the total reflection of right-angle prism to make linear polarization become elliptical polarized light.

Polarized condition switching part 4 though for example be because the elliptical polarized light light beam incident that the total reflection of right-angle prism causes utilizes the effect of 1/4 wavelength plate 4a to be transformed into the linear polarization light beam, is incident in 1/2 wavelength plate 4b.The crystal optics axle of 1/2 wavelength plate 4b, the plane of polarisation of the polarisation that is in line of corresponding incident are set 0 degree or 90 for when spending, and are incident in the light beam of the linear polarization of 1/2 wavelength plate 4b, and its plane of polarisation can not change and pass through.

Again, the crystal optics axle of 1/2 wavelength plate 4b, the plane of polarisation of the linear polarization of corresponding incident are incident in the plane of polarisation of the linear polarization light beam of 1/2 wavelength plate 4b with the situation of 45 degree settings, only change the light that is transformed into linear polarization with 90 degree.Moreover the crystal optics axle of the quartzy prism of depolariser 4c, the plane of polarisation of the linear polarization of corresponding incident are configured to the situation of 45 degree, and the light of the linear polarization of the quartzy prism of incident is transformed into the light (non-polarization light) of non-polarized condition.

In polarized condition switching part 4,4c locatees in illumination path when depolariser, and the plane of polarisation of linear polarization that makes the relative incident of crystal optics axle of quartzy prism is 45 degree.In addition, the plane of polarisation of the linear polarization of the relative incident of crystal optics axle of quartzy prism, when being set at the angle of 0 degree or 90 degree, the plane of polarisation of the linear polarization of the quartzy prism of incident can not change and pass through.Again, the plane of polarisation of the linear polarization of the relative incident of crystal optics axle of 1/2 wavelength plate 4b, when being set at the angle of 22.5 degree, the light of the linear polarization of incident 1/2 wavelength plate 4b is transformed into and contains that plane of polarisation can not change and by linear polarization composition and the plane of polarisation light of the non-polarized condition of the linear polarization composition that changes of 90 degree only.

For polarized condition switching part 4, as above-mentioned, the light of linear polarization is incident in 1/2 wavelength plate 4b, is for following simple declaration, have the light of the linear polarization (to call Z direction polarisation in the following text) of polarization direction (direction of an electric field) in the Z of Fig. 1 direction, it is incident in 1/2 wavelength plate 4b.When depolariser 4c locatees in illumination path, the plane of polarisation (polarization direction) that is incident in the relative Z direction of the crystal optics axle polarisation of 1/2 wavelength plate 4b is set at 0 degree or 90 degree, and be incident in the Z direction polarisation of 1/2 wavelength plate 4b, the Z direction polarisation that its plane of polarisation can not change passes through, and is incident in the quartzy prism of depolariser 4c.The crystal optics axle of quartzy prism, the plane of polarisation of the Z direction polarisation of relative incident, because be set at the angles of 45 degree, the light of the quartzy prism Z of incident direction polarisation is transformed into the light of non-polarized condition.

Pass quartzy prism by the light of non-polarization light, pass that the quartz prism of (compensator) as compensation is incident in diffractive optical elements 5 with non-polarized condition in order to compensate the light direct of travel.On the one hand, the plane of polarisation that is incident in the relative Z direction of the crystal optics axle polarisation of 1/2 wavelength plate 4b is set at 45 when spending, be incident in the light of the Z direction polarisation of 1/2 wavelength plate 4b, its plane of polarisation only 90 degree changes, have the light of the linear polarization (to call the directions X polarisation in the following text) of polarization direction (direction of an electric field) as directions X, be incident in the quartzy prism of depolariser 4c at Fig. 1.Be incident in the plane of polarisation of directions X polarisation of the crystal optics axle of quartzy prism relatively, because be set at 45 degree, the light of the directions X polarisation of the quartzy prism of incident is transformed into non-polarized condition, and pass quartz prism, and be incident in diffractive optical elements 5 with non-polarized condition.

Otherwise, at depolariser 4c when illumination path is backed out, when the crystal optics axle that is incident in 1/2 wavelength plate 4b is set at 0 degree or 90 and spends with respect to the plane of polarisation of Z direction polarisation, the light that is incident in the Z direction polarisation of 1/2 wavelength plate 4b can not change and pass through, and is incident in diffractive optical elements 5 with Z direction polarized condition.On the other hand, the crystal optics axle that is incident in 1/2 wavelength plate 4b is set at 45 when spending with respect to the plane of polarisation of Z direction polarisation, be incident in the light of the Z direction polarisation of 1/2 wavelength plate 4b, plane of polarisation can only change 90 degree and become the light of directions X polarisation, and is incident in diffractive optical elements 5 with the directions X polarized condition.

As above-mentioned, for polarized condition switching part 4, the location that utilizes decision depolariser 4c to insert illumination path can make the light of non-polarized condition be incident in diffractive optical elements 5.Again, depolariser 4c is backed out from illumination path, and utilize to set the crystal optics axle that makes 1/2 wavelength plate 4b be 0 degree or 90 degree with respect to the plane of polarisation of the Z direction polarisation of incident, can make the light of Z direction polarized condition be incident in diffractive optical elements 5.Moreover depolariser 4c backs out from illumination path, and utilize to set the crystal optics axle that makes 1/2 wavelength plate 4b be 45 degree with respect to the plane of polarisation of the Z direction polarisation of incident, can make the light of directions X polarized condition be incident in diffractive optical elements 5.

In other words, for polarized condition switching part 4, the effect of the polarized condition switching part that utilization is made up of 1/4 wavelength plate 4a, 1/2 wavelength plate 4b and depolariser 4c, the polarized condition of the incident light of past diffractive optical elements 5 (and then polarized condition of the light of illumination cover curtain M and wafer W), can between linear polarization state and non-polarized condition, switch, in the situation of linear polarization state, can switch in (between Z direction polarized condition and the directions X polarized condition) between the orthogonal polarized condition.

Moreover, for polarized condition switching part 4,1/2 wavelength plate 4b is backed out from illumination path with depolariser 4c, and utilize the crystal optics axle of 1/4 wavelength plate 4a to set desired angle with respect to the elliptical polarized light of incident, the light of rotatory polarization can be incident in diffractive optical elements 5.On as another, utilize the effect of 1/2 wavelength plate 4b, the polarized condition of the incident light of past diffractive optical elements 5, can set for has the linear polarization of polarization direction state in any direction.

Take second place, circular cone prismatic mirror system 8, along light source side, be that plane and subtend cover curtain side are the 1st 8a of prism portion of recessed cone shape flexion face by the subtend light source side, being plane and subtend light source side with subtend cover curtain side is constituted by the 2nd 8b of prism portion of the flexion face of dome taper.The dome taper flexion face of the recessed coniform flexion face of the 1st 8a of prism portion and the 2nd 8b of prism portion is can engage and complementary shape.Again, the one at least of the 1st 8a of prism portion and the 2nd 8b of prism portion is configured and can moves along optical axis AX.Between the dome taper flexion face of the recessed coniform flexion face of the 1st 8a of prism portion and the 2nd 8b of prism portion is variable at interval.

In this, be the state that is bonded with each other for the recessed coniform flexion face of the 1st 8a of prism portion and the dome taper flexion face of the 2nd 8b of prism portion, circular cone prismatic mirror system 8 is as the function of planopaallel plate, and can not have influence on the wheel belt shape secondary souce that is formed.Yet, make between the dome taper flexion face of the recessed coniform flexion face of the 1st 8a of prism portion and the 2nd 8b of prism portion from the time, circular cone prismatic mirror system 8 is as the function of so-called optical beam expander.Therefore, along with the interval variation of circular cone prismatic mirror system 8, change incident angle of light to deciding face 7.

Fig. 2 illustrates relative wheel belt shape secondary souce, the Action Specification of circular cone prismatic mirror system.With reference to Fig. 2, state (to call standard state in the following text) in the focal length minimum value that is spaced apart zero and flexible lens 9 of setting circular cone prismatic mirror system 8, be formed minimum wheel belt shape secondary souce 30a, utilization makes the interval of circular cone prismatic mirror system 8 enlarge to institute's definite value from zero, its width (1/2 of the difference of external diameter and internal diameter: represent with arrow among the figure) can not change, external diameter enlarges with internal diameter, and is varied to wheel belt shape secondary souce 30b.In other words, utilize the effect of circular cone prismatic mirror system 8, the width of wheel belt shape secondary souce can not change, and it is taken turns band and changes than (inner/outer diameter) and size (external diameter).

Fig. 3 illustrates relative wheel belt shape secondary souce, the Action Specification of flexible lens.With reference to Fig. 3, the wheel belt shape secondary souce 30a that is formed in standard state utilizes the focal length of flexible lens 9 to enlarge to institute's definite value from minimum value, and its all shape similarly enlarges and is varied to wheel belt shape secondary souce 30c.In other words, utilize the effect of flexible lens 9, the wheel band of wheel belt shape secondary souce can not change than, and its width changes with size (external diameter).

Fig. 4 illustrates the inner structure signal oblique view of the polarisation monitor of Fig. 1.With reference to Fig. 4, polarisation monitor 12 comprises: the 1st optical splitter 12a that is configured in the light path between little fly's-eye lens 11 and the light collection system 13.The 1st optical splitter 12a for example is a kenel of utilizing the parallel panel (promptly being plain glass) that not have coating that quartz glass forms, and its have with the reflected light of the different polarized condition of the polarized condition of incident light function from the light path taking-up.

Utilize the 1st optical splitter 12a and, be incident in the 2nd optical splitter 12b from the light that light path is removed.The 2nd optical splitter 12b is identical with the 1st optical splitter 12a, for example is the parallel panel kenel that not have coating of utilizing quartz glass to form, and it has the function that makes with the reflected light generation of the different polarized condition of the polarized condition of incident light.Then, set the S polarisation that the P polarisation that makes relative the 1st optical splitter 12a becomes relative the 2nd optical splitter 12b, and the S polarisation of relative the 1st optical splitter 12a becomes the P polarisation of relative the 2nd optical splitter 12b.

Again, see through only the utilizing the 1st photometric detector 12c of the 2nd optical splitter 12b and detected, the 2nd optical splitter 12b be reflected only utilize the 2nd photometric detector 12d and detected.Control part (not being shown in figure) is defeated by in the output of the 1st photometric detector 12c and the 2nd photometric detector 12d respectively.Control part drives 1/4 wavelength plate 4a, 1/2 wavelength plate 4b and the depolariser 4c that constitutes polarized condition switching part 4 according to need.

As above-mentioned,,, come down to difference for the reflectivity of P polarisation and the reflectivity of S polarisation about the 1st optical splitter 12a and the 2nd optical splitter 12b.Therefore, for polarisation monitor 12, reflected light from the 1st optical splitter 12a, for example contain about 10% S polarized component toward the incident light of the 1st optical splitter 12a (is P polarized component to the 2nd optical splitter 12b to the S polarized component of the 1st optical splitter 12a), and for example toward about 1% P polarized component of the incident light of the 1st optical splitter 12a (is S polarized component to the 2nd optical splitter 12b to the P polarized component of the 1st optical splitter 12a).

Again, reflected light from the 2nd optical splitter 12b, for example contain P polarized component toward about 10% * 1%=0.1% of the incident light of the 1st optical splitter 12a (is S polarized component to the 2nd optical splitter 12b to the P polarized component of the 1st optical splitter 12a), with for example toward about 1% * 10%=0.1% of the incident light of the 1st optical splitter 12a S polarized component (is P polarized component to the 2nd optical splitter 12b to the S polarized component of the 1st optical splitter 12a).

So, respond its reflection characteristic for polarisation monitor 12, the 1 optical splitter 12a and have the function that the reflected light with the different polarized condition of incident light polarized condition is taken out from light path.Its result, seldom be subjected to the influence of the polarisation change that the 2nd optical splitter 12b causes, according to the output of the 1st photometric detector 12c (about the light intensity data that sees through of the 2nd optical splitter 12b, promptly be light intensity data) from the identical approximately polarized condition of reflected light of the 1st optical splitter 12a, can detect toward the polarized condition (degree of polarization) of the incident light of the 1st optical splitter 12a, and then the polarized condition of the illumination light of past cover curtain M.

Again, for polarisation monitor 12, the P polarisation that is set to relative the 1st optical splitter 12a is the S polarisation to the 2nd optical splitter 12b, and is P polarisation to the 2nd optical splitter 12b to the S polarisation of the 1st optical splitter 12a.Its result, according to the output of the 2nd photometric detector 12d (about the 1st optical splitter 12a and the 2nd optical splitter 12b by catoptrical intensity data in turn), be not subjected in fact toward the influence of the variation of the polarized condition of the incident light of the 1st optical splitter 12a, can detect toward the light quantity (intensity) of the incident light of the 1st optical splitter 12a, and then the light quantity of the illumination light of past cover curtain M.

Then, use polarisation monitor 12, detect, and then can judge that whether past illumination light of covering curtain M is desired non-polarized condition, linear polarization state or rotatory polarization state toward the polarized condition of the incident light of the 1st optical splitter 12a.Control part is according to the result that detects by polarisation monitor 12, confirm whether toward the illumination light of cover curtain M (and then wafer W) be the situation of desired non-polarized condition, linear polarization state or rotatory polarization state, driving and adjust 1/4 wavelength plate 4a, 1/2 wavelength plate 4b and the depolariser 4c that constitutes polarized condition switching part 4, is desired non-polarized condition, linear polarization state or rotatory polarization state and can adjust toward the state of the illumination light of covering curtain M.

Moreover, replace the 4 extremely illuminating diffractive optical elements (be not shown in figure) of wheel with illuminating diffractive optical elements 5, by being set in the illumination path, can carry out the illumination of 4 utmost points.4 extremely illuminating diffractive optical elements have the situation of the parallel beam of rectangular-shaped section in incident, and the function that forms the light intensity distributions of 4 utmost point shapes in its far field is arranged.Therefore, pass the light beam of 4 extremely illuminating diffractive optical elements,, form 4 utmost point shape irradiation areas of for example being formed as 4 toroidal irradiation areas at center with optical axis AX at the plane of incidence of little fly's-eye lens 11.Its result, identical near the rear side focus face of little fly's-eye lens 11 or its with the irradiation area that is formed on the plane of incidence, be formed the secondary souce of 4 utmost point shapes.

Again, replace the diffractive optical elements (not being shown in figure) that wheel is used with the circular illumination of illuminating diffractive optical elements 5,, can carry out general circular illumination by being set in the illumination path.The diffractive optical elements that circular illumination is used has the situation of the parallel beam of rectangular-shaped section in incident, and the function that forms the light intensity distributions of toroidal in its far field is arranged.Therefore, pass the light beam of the diffractive optical elements that circular illumination uses,, form 4 utmost point shape irradiation areas of for example being formed as central circular shape irradiation area with optical axis AX at the plane of incidence of little fly's-eye lens 11.Its result, identical near the rear side focus face of little fly's-eye lens 11 or its with the irradiation area that is formed on the plane of incidence, be formed the secondary souce of toroidal.

Moreover, replace wheel other multipole illuminating diffractive optical elements (not being shown in figure) with illuminating diffractive optical elements 5, by being set in the illumination path, can carry out various multipole illuminations (illumination of 2 utmost points, 8 utmost point illuminations etc.).Similarly, replace the diffractive optical elements that appropriate characteristics arranged of wheel,, can carry out the conversion illumination of various forms by being set in the illumination path with illuminating diffractive optical elements 5.

Fig. 5 illustrates the inner structure synoptic diagram of the polarization conversion element of Fig. 1.Fig. 6 illustrates quartzy optical activity key diagram.Fig. 7 illustrates the effect that utilizes polarization conversion element, is configured to the wheel belt shape secondary souce synoptic diagram of Zhou Fangxiang polarized condition.According to the polarization conversion element 10 of the embodiment of the invention, be configured in the positive front of little fly's-eye lens 11, promptly be that illumination optics device is (near 1～PL) pupil or its.Therefore, in the situation of wheel band illumination, 10 incidents have the about wheel belt shape of section and with the light beam of optical axis AX as the center to polarization conversion element.

With reference to Fig. 5, polarization conversion element 10 has the effective coverage of all optical axis AX as the centre wheel band shape, the effective coverage of its wheel belt shape with optical axis AX as the center, utilize circumferencial direction be divided into 8 fan shape primary element be configured.At these 8 primary elements, clipping the relative a pair of primary element of optical axis AX has identical characteristics mutually.Promptly be, 8 primary elements, prolonging thickness (length of optical axis direction) that light passes direction (Y direction) mutually 4 kinds of different primary element 10A～10D respectively contain 2.

Particularly, set the thickness maximum of the 1st primary element 10A for, the thickness minimum of the 4th primary element 10D, the thickness of the 2nd primary element 10B is bigger than the thickness of the 3rd primary element 10C.Its result, a side's of polarization conversion element 10 face (for example plane of incidence) is plane, and another side (for example exit facet), utilizes the thickness difference of each primary element 10A～10D, becomes concavo-convex.Again, two-sided (plane of incidence is with exit facet) that can polarization conversion element 10 forms concavo-convex.

Again, present embodiment, each primary element 10A～10D is to utilize active optical material that is is to constitute as the quartzy of crystalline material that the crystal optics axle of each primary element 10A～10D is consistent approximately with optical axis AX, promptly be set for consistent approximately with the direct of travel of incident light.Below, with reference to Fig. 6, carry out simple declaration for the optical activity of crystal.With reference to Fig. 6, be the parallel panel optic material 100 that crystal constituted of d by thickness, its crystal optics axle is configured to consistent with optical axis AX.Like this situation is utilized the optical activity of optic material 100, and the polarization direction of the linear polarization of incident only rotates an angle θ to optical axis AX state is penetrated.

At this moment, the optical activity of optic material 100 causes the rotation angle of polarization direction (optically-active angle) θ, utilizes the thickness d and the optically-active energy ρ of optic material 100, represents with following formula (a).

θ＝d.ρ (a)

Generally, quartzy optically-active energy ρ is wavelength interdependence (its different optically-actives of interdependent use light wavelength can be worth: optically-active disperses), particularly, uses light wavelength short, has the big tendency that heals.According to the 167th page record at " applied optics II ", with respect to the light of the wavelength with 250.3nm, quartzy optically-active can ρ be 153.9 degree/mm.

At present embodiment, the 1st primary element 10A is configured to thickness d A, and in the situation of the light incident of the linear polarization of Z direction polarisation, the Z direction makes+direction of 180 degree rotations around Y-axis, promptly is to have the light of the linear polarization of polarization direction to make ejaculation in the Z direction.Therefore, in this situation, among the wheel belt shape secondary souce 31 as shown in Figure 7, be subjected to the light beam of the optically-active effect of a pair of the 1st primary element 10A, the polarization direction of the light beam by a pair of circular-arc regional 31A that forms is in the Z direction.

The 2nd primary element 10B is configured to thickness d B, and when the light incident of the linear polarization of Z direction polarisation, the Z direction makes+direction of 135 degree rotations around Y-axis, promptly is to make the direction of-45 degree rotations in the Z direction around Y-axis, has the light of the linear polarization of polarization direction to penetrate.Therefore, in this situation, among the wheel belt shape secondary souce 31 as shown in Figure 7, be subjected to the light beam of the optically-active effect of a pair of the 2nd primary element 10B, the polarization direction of the light beam by a pair of circular-arc regional 31B that forms is the direction that the Z direction spends rotation-45 around Y-axis.

The 3rd primary element 10C is configured to thickness d C, and when the light incident of the linear polarization of Z direction polarisation, the Z direction makes+direction of 90 degree rotations around Y-axis, promptly is to have the light of the linear polarization of directions X polarization direction to penetrate.Therefore, in this situation, among the wheel belt shape secondary souce 31 as shown in Figure 7, be subjected to the light beam of the optically-active effect of a pair of the 3rd primary element 10C, the polarization direction of the light beam by a pair of circular-arc regional 31C that forms is at directions X.

The 4th primary element 10D is configured to thickness d D, when the light incident of the linear polarization of Z direction polarisation, the Z direction around Y-axis make+directions of 45 degree rotations have the light of the linear polarization of polarization direction to penetrate.Therefore, in this situation, among the wheel belt shape secondary souce 31 as shown in Figure 7, be subjected to the light beam of the optically-active effect of a pair of the 4th primary element 10D, the polarization direction of the light beam by a pair of circular-arc regional 31D that forms is the direction that the Z direction spends rotation+45 around Y-axis.

Moreover, 8 primary elements that are formed are respectively made up can obtain polarization conversion element 10, also can utilize quartz wafer to form desired concaveconvex shape (section is poor) and obtain polarization conversion element 10 with planopaallel plate.Again, not with polarization conversion element 10 when light path is backed out, can carry out common circular illumination, and the central optical of setting toroidal is by regional 10E, the footpath direction size of the effective coverage that its size is a polarization conversion element 10 more than or equal to 3/10, be preferably more than or equal to 1/3, and do not have optical activity.In this, central optical is by regional 10E, can utilize the optical material that does not have optical activity for example quartzy and form, and also can be simple toroidal opening.But central optical is not the necessary element of polarization conversion element 10 by regional 10E.Moreover central optical is determined with non-this regional border by Zhou Fangxiang polarized condition zone by the size of regional 10E.

In present embodiment, in Zhou Fangxiang polarisation when illumination wheel band (light beam of the secondary souce by wheel belt shape is configured to the deformation illumination of Zhou Fangxiang polarized condition), there is the light of the linear polarization of Z direction polarisation to be incident in polarization conversion element 10.Its result, near the rear side focus face of little fly's-eye lens 11 or its, as shown in Figure 7, the secondary souce of wheel belt shape (pupil of wheel belt shape distributes) 31 is formed, and the light beam of the secondary souce 31 by this wheel belt shape is configured to the Zhou Fangxiang polarized condition.For the Zhou Fangxiang polarized condition, the light beam of the circular-arc regional 31A～31D of the secondary souce 31 by constituting wheel belt shape respectively, along the circumferencial direction of each circular-arc regional 31A～31D, and be approximately with consistent as the tangential direction of the circle at center with optical axis AX at the polarization direction of the linear polarization state of center.

Then, different in present embodiment with the conventional art that light loss takes place greatly because of aperture, utilize the optically-active effect of polarization conversion element 10, can tangible light loss not take place, can form the secondary souce 31 of the wheel belt shape of Zhou Fangxiang polarized condition.In other words,, suppress light loss well, can form the illumination profile of the wheel belt shape of Zhou Fangxiang polarized condition for the illumination optics device of present embodiment.Moreover for present embodiment, because use the polarisation effect of optical element, polarization conversion element easy to manufacture can very slow setting for the thickness deviation of typical each primary element, reaches excellent results.

Again, according to the Zhou Fangxiang polarisation wheel belt shape illumination that the wheel belt shape of Zhou Fangxiang polarized condition illumination pupil distributes, irradiated as illuminated final wafer W only is the polarized condition of Main Ingredients and Appearance with the S polarisation.In this, the S polarisation is the linear polarization (direction of vertical incidence face is the polarisation of vector vibrations electrically) that the polarization direction of relative plane of incidence vertical direction is arranged.But the plane of incidence is defined as the interface (plane of illumination: wafer W surface), be included in the interface normal on its aspect and the face of incident light that arrives medium when light.

Its result for the illumination of Zhou Fangxiang polarisation wheel belt shape, can promote the optical property (depth of focus etc.) of projection optical system, can obtain going up at wafer (photonasty substrate) the cover curtain pattern image of high contrast.Promptly be,, can suppress light loss well, and form the illumination optics device that the wheel belt shape illumination pupil of Zhou Fangxiang polarized condition distributes because use for the embodiment of the invention, with the appropriate illumination condition can be loyal and high production capacity ground with the fine pattern transcription.

Then, in present embodiment, utilization has the light of the linear polarization of directions X polarization direction to make its incident polarization conversion element 10, light beam by wheel belt shape secondary souce 32 is set at footpath direction polarized condition as shown in Figure 8, and carries out footpath direction polarisation wheel band illumination (being configured to the deformation illumination of footpath direction polarized condition by the light beam of wheel belt shape secondary souce 32).In footpath direction polarized condition, pass through the light beam of the circular-arc regional 32A～32D of formation wheel belt shape secondary souce 32 respectively, along the circumferencial direction of each circular-arc regional 32A～32D, and the linear polarization state in the center is approximately with consistent as the radius of a circle mode at center with optical axis AX.

Footpath direction polarisation wheel band illumination according to the wheel belt shape of footpath direction polarized condition illumination pupil distributes is irradiated to the light as illuminated final wafer W, is to be the polarized condition of Main Ingredients and Appearance with the P polarisation.In this, the P polarisation is the linear polarization (parallel plane of incidence direction is the polarisations of vector vibrations electrically) of polarization direction of parallel direction of the plane of incidence of above-mentioned relatively definition.Its result, footpath direction polarisation wheel belt shape illumination, the light reflectivity of applied photoresistance on wafer reduces, and on wafer (photonasty substrate), can obtain good cover curtain pattern image.

Again, in the foregoing description, the light beam of incident polarization conversion element 10, utilize the Z direction linear polarization state of polarization direction is arranged with the linear polarization state that polarization direction is arranged at directions X between switching, and realize that illumination of Zhou Fangxiang polarisation wheel band and footpath direction polarisation wheel band throw light on.But, be not limited to this, for example for the incident beam that the linear polarization state of polarization direction is arranged at Z direction or directions X, utilize polarization conversion element 10 only to make at as shown in Figure 5 the 1st state and around optical axis AX and switch between rotating the 2nd state of 90 degree, can realize illumination of Zhou Fangxiang polarisation wheel band and footpath direction polarisation wheel band illumination.

Again, in the foregoing description, the dead ahead of little fly's-eye lens 11 configuration polarization conversion element 10.But, be not limited to this, the general illumination device is (near 1～PL) pupil or its, for example near the pupil of projection optical system PL or its, near the pupil of imaging optical system 15 or its, the dead ahead of circular cone prismatic mirror system 8 (pupil of afocal lens 6 or its near) etc. can dispose polarization conversion element 10.

Therefore, if among the projection optical system PL with imaging optical system 15 in configuration polarization conversion element 10 because polarization conversion element 10 desired effective diameters are big easily, considering has any problem obtains the present situation of high-quality big quartz wafer and not good.Again, if the dead ahead of circular cone prismatic mirror system 8 configuration polarization conversion element 10, polarization conversion element 10 desired effective diameters are reduced, but to the distance of the wafer W of final plane of illumination, prevent factor that the coating of reflection from lens and the reflectance coating of mirror etc. can change polarized condition easily intervention in its light path and not good.Promptly be, the preventing of lens reflected the reflectance coating of coating and mirror, easily because the reflectivity of polarized condition (P polarisation and S polarisation) and incident angle and variation, and then changes polarized condition easily.

Again, in the foregoing description, (for example outgoing plane) of its one side at least of polarization conversion element 10 is formed concavo-convex, and then polarization conversion element 10 has discrete (discontinuous) variable thickness to distribute at Zhou Fangxiang.But, be not limited to this, have the thickness distribution of discontinuous approximately variation as polarization conversion element 10 at Zhou Fangxiang, its one side (for example outgoing plane) at least of polarization conversion element 10 can form the curved surface shape.

Again,, utilize the primary element of 88 fan shapes cutting apart of the effective coverage of corresponding wheel belt shape, constitute polarization conversion element 10 in the foregoing description.But, be not limited to this, can for example utilize the primary element of 8 fan shapes that 8 of corresponding circle shape effective coverage cuts apart, or utilize the primary element of 44 fan shapes cutting apart of the effective coverage of corresponding circle shape or wheel belt shape, or utilize the primary element of 16 16 fan shapes cutting apart of the effective coverage of corresponding circle shape or wheel belt shape to constitute polarization conversion element 10.Promptly be, the effective coverage shape of polarization conversion element 10, number (quantity of primary element) etc. is cut apart in the effective coverage, and multiple different variation can be arranged.

Again, in the foregoing description, the brilliant various primary element 10A～10D (and then polarization conversion element 10) that form of water.But, be not limited to this, use active other suitable optical materials can form each primary element.Situation also can use correspondence to use the light of wavelength that the optical material of the above optically-active energy of 100 degree/mm is arranged therewith.Promptly be, if use the optical material that optically-active can be little, the required thickness that obtain the desired rotation angle of polarization direction can be blocked up, and because light loss former thereby not good.

Again, in the foregoing description, polarization conversion element 10 corresponding illumination paths are fixing to be set, and polarization conversion element 10 corresponding illumination paths can be inserted take off setting.Again, in the foregoing description, though the S polarisation of wafer W is combined into example with wheel band illumination group relatively, the also multipole illumination of the S polarisation of wafer W and 2 utmost points or 4 utmost points etc. and circular illumination combination relatively.Again, in the foregoing description, toward the lighting condition of cover curtain M and image-forming condition (numerical aperture and aberration) toward wafer W, for example the kind of the pattern of cover curtain M etc. therefore can automatic setting.

Fig. 9 illustrates the variation synoptic diagram that a plurality of polarization conversion elements can exchange.Again, the distortion of Fig. 9 has the similar structure of embodiment for example shown in Figure 1, and its discrepancy is that it has the turntable 10T (turret) that a plurality of polarization conversion elements can be exchanged.

Figure 10 illustrates turntable 10T as the exchange mechanism of Fig. 9 by the multiple polarization conversion element 10a of mounting～10e synoptic diagram.As Fig. 9 and shown in Figure 10, for variation, with optical axis AX parallel direction as on the rotatable turntable 10T of axle, the polarization conversion element 10a～10e of multiple kind is set, utilize the turning effort of turntable 10T can exchange the polarization conversion element 10a～10e of multiple kind.Again, in Fig. 9, among the polarization conversion element 10a～10e of multiple kind, polarization conversion element 10a only, 10b is shown in figure.Again, for the exchange mechanism as polarization conversion element, be not limited to turntable 10T, for example sliding part also can.

Figure 11 A～11E illustrates multiple polarization conversion element 10a～10e and divides other structural representation.In Figure 11 A, the 1st polarization conversion element 10a has the structure identical with the polarization conversion element 10 of embodiment shown in Figure 5.In Figure 11 B, the 2nd polarization conversion element 10b, though have the similar structure with polarization conversion element 10a shown in Figure 11 A, difference is to be provided with polarisation in central optical by regional 10E to clear up the material 104c of portion.This polarisation is cleared up the material 104c of portion, has and depolariser 4c same structure shown in Figure 1, and the function that the light of the linear polarization of incident is transformed into the light of non-polarized condition is arranged.

In Figure 11 C, the 3rd polarization conversion element 10c has the similar structures with polarization conversion element 10a shown in Figure 11 A, and difference is the size of central optical by regional 10E big (width of the 1st～the 4th primary element 10A～10D is narrower).Again, in Figure 11 D, the 4th polarization conversion element 10d has the similar structures with polarization conversion element 10c shown in Figure 11 C, and discrepancy is that central optical is provided with polarisation by regional 10E and clears up the material 104c of portion.

In Figure 11 E, the 5th polarization conversion element 10e is made of 8 primary elements, but is made of 6 primary element 10C, 10F, 10G combination.The 5th polarization conversion element 10e, so that the effective coverage of wheel belt shape to be arranged as the center as all optical axis AX, and the effective coverage of this wheel belt shape, utilizes to be divided into 6 fan shape primary element 10C, 10F, 10G at circumferencial direction etc. and to be configured as the center with optical axis AX.At these 6 fan shape primary element 10C, 10F, 10G, clipping the relative a pair of primary element of optical axis AX has identical characteristics mutually.Promptly be, 6 primary element 10C, 10F, 10G, along the thickness (length of optical axis direction) that sees through direction (Y direction) of light mutually different each other 3 kind primary element 10C, 10F, 10G respectively contain 2.

Then, primary element 10C has identical function portion material with the 3rd primary element 10C shown in Figure 7, and omits its function explanation.Primary element 10F has been set thickness d F, in the Z direction linear polarization incident situation of polarization direction is arranged, and the Z direction makes the direction of rotation+150 degree around Y-axis, promptly is the light ejaculation of linear polarization of the polarization direction of the Z direction direction that makes rotation-30 degree around Y-axis.Primary element 10G has been set thickness d G, in the Z direction linear polarization incident situation of polarization direction is arranged, and the Z direction makes the light of linear polarization of the polarization direction of rotation+30 degree direction penetrate around Y-axis.Again, replace central optical, polarisation also can be set clear up the material 104c of portion by regional 10E.

Again, get back to Figure 10, the not peristome 40 of mounting polarization conversion element is set on turntable 10T, for the situation that is not the polarizing illumination of Zhou Fangxiang polarizing illumination, carry out the situation of the non-polarizing illumination of big σ value (the cover curtain side numerical aperture of the cover curtain side numerical aperture/projection optical system of σ value=illumination optics device), this peristome 40 is arranged in illumination path.

Again, as above-mentioned, by the central portion of mounting in polarization conversion element 10a～10e of turntable 10T, though with by the opening of toroidal or do not have the material of optical activity constitute central optical by regional 10E or be provided with polarisation clear up the material 104c of portion be illustration it, also can dispose central optical is cleared up the material 104c of portion by regional 10E or polarisation polarization conversion element (polarization conversion element of being made up of the primary element of fan shape) be not set.

Figure 12 A～12C illustrates the illustration intention that the effect that utilizes polarization conversion element is configured to the secondary souce of Zhou Fangxiang polarized condition.Again, in Figure 12 A～12C, the polarization conversion element for understanding easily redraws in diagram.

Figure 12 A, replace diffractive optical elements 5, the diffractive optical elements (light beam conversion element) of the light intensity distributions of (or Fraunhofer diffraction zone) formation 8 utmost point shapes is set in the light path in the far field, and polarization conversion element 10a or 10b are set at the situation of illumination path, show it with the secondary souce 33 of 8 utmost point shapes.Therefore, the light beam of the secondary souce 33 by 8 utmost point shapes is configured to the Zhou Fangxiang polarized condition.For the Zhou Fangxiang polarized condition, the light beam of 8 border circular areas 33A～33D of the secondary souce 33 by constituting 8 utmost point shapes respectively, being combined into round circumferencial direction by 8 border circular areas 33A～33D, promptly is the linear polarization state with the consistent approximately polarization direction of the tangential direction of the circle of these 8 border circular areas 33A～33D combinations.Again, in Figure 12 A, though the secondary souce 33 of 8 utmost point shapes with 8 border circular areas illustrations that 33A～33D is constituted it, be not limited to 8 region shapes for circular.

Figure 12 B, replace diffractive optical elements 5, the diffractive optical elements (light beam conversion element) of the light intensity distributions of (or Fraunhofer diffraction zone) formation 4 utmost point shapes is set in the light path in the far field, and polarization conversion element 10c or 10d are set at the situation of illumination path, show it with the secondary souce 34 of 4 utmost point shapes.Therefore, the light beam of the secondary souce 34 by 4 utmost point shapes is configured to the Zhou Fangxiang polarized condition.For the Zhou Fangxiang polarized condition, the light beam of 4 regional 34A, 34C of the secondary souce 34 by constituting 4 utmost point shapes respectively, being combined into round circumferencial direction by 4 regional 34A, 34C, promptly is the linear polarization state with the consistent approximately polarization direction of the tangential direction of the circle of these 4 regional 34A, 34C combination.Again, in Figure 12 B, though the secondary souce 34 of 4 utmost point shapes with 4 elliptical region 34A, illustration that 34C is constituted it, be not limited to 4 region shapes for oval.

Figure 12 C, replace diffractive optical elements 5, the diffractive optical elements (light beam conversion element) of the light intensity distributions of (or Fraunhofer diffraction zone) formation 6 utmost point shapes is set in the light path in the far field, and polarization conversion element 10e is set at the situation of illumination path, shows it with the secondary souce 35 of 6 utmost point shapes.Therefore, the light beam of the secondary souce 35 by 6 utmost point shapes is configured to the Zhou Fangxiang polarized condition.For the Zhou Fangxiang polarized condition, pass through 6 regional 35C, 35F of the secondary souce 35 of formation 6 utmost point shapes, the light beam of 35G respectively, being combined into round circumferencial direction by 6 regional 35C, 35F, 35G, promptly is the linear polarization state with the consistent approximately polarization direction of the tangential direction of the circle of these 6 regional 35C, 35F, 35G combination.Again, in Figure 12 C, though the secondary souce 35 of 6 utmost point shapes with 6 about trapezoidal shape zones 35C, 35F, illustration that 35G is constituted it, being not limited to 6 region shapes is about trapezoidal shape.

Again, in the foregoing description and variation, though polarization conversion element is fixed around optical axis, polarization conversion element also can make rotation around optical axis.Figure 13 is the structure skeleton diagram of being arranged to around the rotatable polarization conversion element 10f of optical axis.

In Figure 13, polarization conversion element 10f is constituted by 4 primary element 10A, 10C.It is the wheel belt shape effective coverage at center that polarization conversion element 10f has as all optical axis AX, and this wheel belt shape effective coverage with optical axis AX be the center circumferencial direction by etc. be divided into primary element 10A, the 10C of 4 fan shape.In these 4 primary element 10A, 10C, clipping the relative a pair of primary element of optical axis AX has identical characteristics mutually.Promptly be, 4 primary element 10A, 10C, 2 kinds of different each other primary element 10A, 10C contain 2 respectively in the thickness that passes direction (Y direction) along light (length of optical axis direction) phase.

In this, because primary element 10A is portion's material that identical function is arranged with the 1st primary element 10A shown in Figure 7, primary element 10C has portion's material of identical function with the 3rd primary element 10C shown in Figure 7, and omits its function explanation.Again, replace central optical by regional 10E, polarisation also can be set clear up the material 104c of portion.

This polarization conversion element 10f sets for and can rotate as the center with optical axis AX, for example with optical axis AX be the center make+45 the degree or-45 the degree can rotate.Figure 14 A～14C illustrates the effect that utilizes polarization conversion element 10f, is configured to the illustration intention of the secondary souce of Zhou Fangxiang polarized condition.Again, in Figure 14, be easy understanding, polarization conversion element 10f repeats to illustrate.

Figure 14 A, replace diffractive optical elements 5, the diffractive optical elements (light beam conversion element) of the light intensity distributions of (or Fraunhofer diffraction zone) formation 2 utmost point shapes is set in the light path in the far field, and polarization conversion element 10f is the state (normal condition) of 0 degree in the anglec of rotation, and the secondary souce 36 (36A) with 2 utmost point shapes under the situation in being set at illumination path shows it.In this, the light beam by secondary souce 36 (36A) is set to the longitudinal direction polarization direction.

Figure 14 B, replace diffractive optical elements 5, the diffractive optical elements (light beam conversion element) of the light intensity distributions of (or Fraunhofer diffraction zone) formation 4 utmost point shapes is set in the light path in the far field, and polarization conversion element 10f is the state (normal condition) of 0 degree in the anglec of rotation, and the secondary souce 37 with 4 utmost point shapes under the situation in being set at illumination path shows it.In this, the light beam by secondary souce 37 is set to the Zhou Fangxiang polarization direction.Again, in Figure 14 B, (Z direction) and left and right directions (directions X) about the light intensity distributions of 4 utmost point shapes is confined in the paper.

In the Zhou Fangxiang polarized condition, the light beam of 4 border circular areas 37A, 37C of the secondary souce 37 by constituting 4 utmost point shapes respectively, the circumferencial direction of the circle that is combined into by these 4 border circular areas 37A, 37C promptly is the linear polarization state that the consistent approximately polarization direction of the tangential direction of the circle that is combined into these 4 border circular areas 37A, 37C is arranged.Again, in Figure 14 B, though be that secondary souce 37 with 4 utmost point shapes is made of 4 border circular areas 37A, 37C and shows it, the shape in 4 zones is not defined as circle.

Figure 14 C, the diffractive optical elements that replaces Figure 14 B, in far field (or Fraunhofer diffraction zone) limitation paper+-45 spend (+135 spend) direction in 45 degree (135 degree) directions and the paper, the diffractive optical elements (light beam conversion element) that forms the light intensity distributions of 4 utmost point shapes is set in the light path, and polarization conversion element 10f is state (the relative datum state of+45 degree in the anglec of rotation, the states of clockwise rotation 45 degree) make rotation and be arranged under the situation in the illumination path, show it with the secondary souce 38 of 4 utmost point shapes.

In Figure 14 C, 1/2 wavelength plate 4b in the polarized condition switching part 4 makes rotation around optical axis, and polarization conversion element 10f makes+45 degree the linear polarization incident of (135 degree direction) polarization direction relatively.In this, because primary element 10A has the polarization direction of the linear polarization of the incident of making only to spend the function of (n is an integer) in Rotate 180 degree ± n * 180, and primary element 10C has the polarization direction that makes the incident linear polarization only to revolve to turn 90 degrees ± function of n * 180 degree (n is an integer), and the light beam of the secondary souce 38 by 4 utmost point shapes is set to the Zhou Fangxiang polarized condition.

In the Zhou Fangxiang polarized condition shown in Figure 14 C, the light beam of 4 border circular areas 38B, 38D of the secondary souce 38 by constituting 4 utmost point shapes respectively, the circumferencial direction of the circle that is combined into by these 4 border circular areas 38B, 38D promptly is the linear polarization state that the consistent approximately polarization direction of the tangential direction of the circle that is combined into these 4 border circular areas 38B, 38D is arranged.Again, in Figure 14 C, though be that secondary souce 38 with 4 utmost point shapes shows it by the example that 4 border circular areas 38B, 38D are constituted, the shape in 4 zones is not defined as circle.

So, utilize the change action of the polarization direction of polarized condition switching part 4, turning effort with polarisation switching device 10f, though 4 utmost point shape secondary souces are confined to+45 degree (135 degree) direction and-45 degree (+135 degree) direction, though it promptly is direction in length and breadth that 4 utmost point shape secondary souces are confined to 0 degree (+180 degree) direction and 90 degree (270 degree), though it promptly is direction in length and breadth that 2 utmost point shape secondary souces are confined to 0 degree (+180 degree) direction or 90 degree (270 degree), also can realize the Zhou Fangxiang polarized condition.

Cut apart by waiting and, also can rotate at circumferencial direction as the center with optical axis AX around optical axis AX by the polarization conversion element that the primary element of 8 fan shapes constitutes again.Shown in Figure 15 A, for example by 8 polarization conversion elements of cutting apart that primary element constituted (for example polarization conversion element 10a), if make only rotation+45 degree around optical axis AX, the light beam of 8 border circular areas 39A～39D by constituting 8 utmost point shape secondary souces 39 respectively, the circumferencial direction (tangential direction of the circle that 8 border circular areas 39A～39D are combined into) with circle that this 8 border circular areas 39A～39D relatively are combined into makes the only linear polarization state of the polarization directions of rotation-45 degree.

Again, shown in Figure 15 B, pass through the light beam of 8 border circular areas of formation 8 utmost point shape secondary souces respectively, in the circumferencial direction of the circle that has relative these 8 border circular areas to be combined into (tangential direction of the circle that 8 border circular areas are combined into), long axis direction is only rotated the situation of the elliptical polarized light of+45 polarization directions of spending, and the polarization conversion element shown in Figure 15 A (for example polarization conversion element 10a) utilizes around optical axis AX and makes only rotation+45 degree, shown in Figure 15 C, can obtain about Zhou Fangxiang polarized condition.

Figure 16 illustrates that polarization conversion element is configured near the pupil of lamp optical system in the position, the positive anterior locations (near the position of light incident side) of circular cone prismatic mirror system 8 is the synoptic diagram of example.Example in Figure 16, utilize the multiple variation effect of flexible lens combination 9, be projected to the size of the plane of incidence central optical of little fly's-eye lens 11 by the picture of regional 10E, can be changed with the size of the picture of each primary element 10A～10D of the plane of incidence that is projected to little fly's-eye lens 11, action by circular cone prismatic mirror system 8, being projected to the picture of each primary element 10A～10D of the plane of incidence of little fly's-eye lens 11, is that the amplitude of radius centered direction is changed with optical axis AX.

Therefore, the polarization conversion element of the central optical of variation as shown in figure 16 by regional 10E (or polarisation is cleared up the material 104c of portion) arranged, be arranged on the situation of light source side compared with the optical system that the effect of conversion multiplying power is arranged (flexible lens 9), the consideration central optical occupies the conversion multiplying power of the flexible lens 9 of zone utilization by regional 10E and is changed, and also can determine the size of central optical by regional 10E.

Again, variation as shown in figure 16, in that being arranged, central optical passes through the polarization conversion element of regional 10E (or polarisation is cleared up the material 104c of portion), be arranged on the situation of light source side compared with there being change wheel band to liken the optical system (circular cone prismatic mirror system 8) of usefulness to, as shown in figure 17, the one at least of preferable meeting the following conditions (1) and condition (2).

(1)(10in+ΔA)/10out＜0.75

(2)0.4＜(10in+ΔA)/10out.

Wherein,

10in: the central optical of polarization conversion element 10 is passed through the effective radius of regional 10E,

10out: the outside effective radius of polarization conversion element 10,

Δ A: take turns the increase part of the inner radius of the light beam of being with the optical system that likens usefulness to by change is arranged.

In this, the situation of do not satisfy condition (1) makes the regional narrow of wheel belt shape that the Zhou Fangxiang polarized condition is transformed by polarization conversion element 10, because can not reach the wheel belt shape of steamboat band ratio or Zhou Fangxiang polarizing illumination that multipole shape secondary souce causes and bad.Again, the do not satisfy condition situation of (2), central optical that can be by polarization conversion element 10 obviously diminishes by the diameter of the light beam in zone, for example can not move outside illumination path when this polarization conversion element 10, polarized condition is constant, and is bad because little σ illumination can not be arranged.

Again, as shown in figure 18, polarization conversion element is configured near the position of pupil of lamp optical system, is in the position of covering the curtain side compared with little fly's-eye lens 11, particularly, also can be arranged on will cover curtain shield 14 picture project near the position pupil of the imaging optical system 15 on the cover curtain.At Figure 16 and embodiment shown in Figure 180, identical with Fig. 9 to the embodiment of Figure 11, a plurality of permutable polarization conversion elements also can be arranged.

Again, at the foregoing description, compared with polarization conversion element 10, when the optical system of wafer W side (lamp optical system and projection optical system) had the situation of polarisation aberration (delay), because the polarisation aberration, polarization direction can change.In this situation, in the influence of the polarisation aberration of considering this optical system, utilize polarization conversion element 10, the preferable direction that can set the plane of polarisation that is rotated.Again, utilize polarization conversion element 10, in the light path of wafer W side, be configured the situation of reflecting part material, be reflected in each polarization direction by this reflecting part material and produce phase differential.At this moment, consider the light beam phase differential that the polarized light property by reflecting surface causes, utilize polarization conversion element 10 also can set the direction of the plane of polarisation that is rotated.

The embodiment that comments metering method of polarized condition then, is described.In present embodiment, maintenance is as the side of the crystal wafer platform (substrate stage) of the wafer W of photonasty substrate, and the wafer face polarisation monitor 90 that use can pass in and out detects the polarized condition of arrival as the light beam of the wafer W of photonasty substrate.Again, wafer face polarisation monitor 90 also can be set in the crystal wafer platform, and also this crystal wafer platform can be arranged on other instrumentation platform.

Figure 19 illustrates the structural representation for the wafer face polarisation monitor 90 of the polarized condition of the light that detects illumination wafer W and light intensity.As shown in figure 19, wafer face polarisation monitor 90 comprises the position or near the pin hole portion material 91 it that can be positioned wafer W.The light of pin hole 91a by pin hole portion material 91, pass near the image planes position that is configured in projection optical system PL or its, as the aligning lens 92 (collimated lens) of focal position, front side and become parallel approximately light beam, and after mirror 93 reflections that are reflected, be incident in relay lens system 94 (relay lens).Pass about parallel beam of relay lens system 94, pass, arrive the detection faces 97a of two-dimensional CCD 97 (Charge Coupled Device, charge-coupled image sensor) as behind 1/4 wavelength plate 95 of phase shifts element and the polarisation optical splitter 96 as polarization element.In this, the ejaculation pupil of the detection faces 97a of two-dimensional CCD 97 and projection optical system PL is optical conjugate roughly, so with the illumination pupil face of illumination optics device optical conjugate roughly.

1/4 wavelength plate 95 is configured and can rotates as the center with optical axis, for this 1/4 wavelength plate 95, is connected in order to be configured to the configuration part 98 of optical axis as the center rotation.So, not 0 situation to the degree of polarization of the illumination light of wafer W, make 1/4 wavelength plate 95 around the optical axis rotation by configuration part 98, and change in the detection faces 97a of two-dimensional CCD 97 light intensity distributions.Therefore, for wafer face polarisation monitor 90, one side is used configuration part 98 and is made 1/4 wavelength plate 95 make rotation around optical axis, and one side detects the variation in detection faces 97a light intensity distributions, and from then on testing result can be measured the polarized condition of illumination light to the method for utilizing the rotatable phase moving meter.

Again, the method for rotatable phase moving meter, for example crane field described " light pencil-give optical tech person's applied optics " is as the write up of Co., Ltd.'s new technology communication (communications).In fact, pin hole portion material 91 (and then pin hole 91a) moves two dimension along the wafer face, in the polarized condition of a plurality of position finding illumination light of wafer face.At this moment, for wafer face polarisation monitor 90,,, in the pupil of illumination light, can measure the distribution of polarized condition according to this detected distribution data because detect variation in the light intensity distributions of two-dimensional detection face 97a.

For wafer face polarisation monitor 90, can replace as 1/4 wavelength plate 95 of phase shifts element and to use 1/2 wavelength plate again.Use the phase shifts element, polarized condition, promptly be to be used to measure 4 Stokes parameters, variation is along the relative angle of the optical axis of phase shifts element and polarization element (polarisation optical splitter 96), phase shifts element or polarization element are backed out from light path, and the light intensity distributions that goes out at detection faces 97a at least 4 different state-detection changes according to need.Again, in present embodiment, though rotate around optical axis as 1/4 wavelength plate 95 of phase shifts element, the polarisation optical splitter 96 as polarization element is rotated around optical axis, the two rotates around optical axis also can to make phase shifts element and polarization element.Again, replace these operations or increase these operations, also can make as 1/4 wavelength plate 95 of phase shifts element and take off with from light path, inserting as the one of the polarisation optical splitter 96 of polarization element or the two.

Again, for wafer face polarisation monitor 90, utilizing the polarized light property of catoptron 93, is the polarized condition that changes light.In this situation, because the polarized light property of the catoptron of knowing in advance 93, according to the influence of the polarized condition of utilizing the resultant polarized light property to catoptron 93 of needed calculating, the measurement result of revisal wafer face polarisation monitor 90 can and correctly be measured the polarized condition of illumination light.Again, be not limited to catoptron, the situation that causes polarized condition by other opticses that change by lens etc. can correctly be measured the polarized condition of illumination light with revisal measurement result in the same manner.

Below, specify the amount of commenting that distributes about the polarized condition in the pupil of illumination light.At first, by a bit (or the tiny area) on pupil, and some light of (tiny area) on the arrival image planes is calculated corresponding specific degree of polarization DSP one by one.In following explanation, use the XYZ coordinate system of Fig. 1, Figure 16, Figure 18 again.Some picture element of (tiny area) corresponding two-dimensional CCD 97 on the above-mentioned pupil, and a bit XY coordinate system of (tiny area) corresponding pin hole 91a on the image planes.

This specific degree of polarization DSP, when by a bit (or tiny area) on pupil, and some intensity of the directions X polarized component (polarisation of the direction of vibration of directions X on pupil) of the particular light ray of (tiny area) on the arrival image planes is Ix, when the intensity of the Y direction polarized component of this particular light ray (polarisation of the direction of vibration of Y direction on pupil) is Iy

(3)DSP＝(Ix-Iy)/(Ix+Iy)。

Again, this specific degree of polarization DSP, corresponding all strength S ₀Horizontal linear polarisation intensity deduct vertical line polarisation strength S ₁, with (S ₁/ S ₀) identical.

Again, by a bit (or tiny area) of passing through on pupil, and some intensity of the directions X polarized component (polarisation of the direction of vibration of directions X on pupil) of the particular light ray of (tiny area) on the arrival image planes is Ix, and the intensity of the Y direction polarized component of this particular light ray (polarisation of the direction of vibration of Y direction on pupil) is Iy, by following formula (4), (5), can be defined in the specific polarizing coefficient RSP of horizontal polarisation (the diffraction light of the corresponding cover curtain pattern that horizontal direction is extended in pattern plane becomes the polarisation of S polarisation) _h, with the specific polarizing coefficient RSP of vertical polarisation (the diffraction light of the corresponding cover curtain pattern that vertical direction is extended in pattern plane becomes the polarisation of S polarisation) _v

(4)RSP _h＝Ix/(Ix+Iy)，

(5)RSP _v＝Iy/(Ix+Iy)，

Wherein, RSP when desirable non-polarizing illumination _h, RSP _vThe two is 50%, RSP when desirable horizontal polarisation _hBe 100%, RSP when desirable vertical polarisation _vBe 100%.

Again, corresponding light by arriving a bit (tiny area) on the image planes at a bit (or tiny area) on the pupil one by one, when in order to following formula (6)～(9) definition degree of polarization V, corresponding to regional some light beam of (tiny area) that arrives on the image planes of desired efficient light sources, can use following formula (10) definition average degree of polarization V (Ave).

(6)V＝(S ₁ ²+S ₂ ²+S ₃ ²) ^1/2/S ₀

＝(S ₁’ ²+S? ₂’ ²+S ₃’ ²) ^1/2

(7)S ₁’＝S ₁/S ₀

(8)S ₂’＝S ₂/S ₀

(9)S ₃’＝S ₃/S ₀

S wherein ₀Be whole intensity, S ₁For horizontal linear polarisation intensity deducts vertical line polarisation intensity, S ₂Be that 45 degree linear polarization intensity deduct 135 degree linear polarization intensity, S ₃For dextrorotation rotatory polarization intensity deducts left-handed rotatory polarization intensity.

(10)V(Ave)＝∑[S ₀(x _i，y _i).V(x _i，y _i)]/∑S ₀(x _i，y _i)。

Again, in formula (10), S ₀(x _i, y _i) be corresponding by desired efficient light sources zone (x _i, y _i) on a bit (or tiny area) and arrive a bit whole strength S of the light of (tiny area) on the image planes ₀, V (x _i, y _i) be corresponding by desired efficient light sources zone (x _i, y _i) on a bit (or tiny area) and arrive some degree of polarization of the light of (tiny area) on the image planes.

Again, corresponding arrive the light of a bit (tiny area) on the image planes, can define average specific polarizing coefficient RSP about horizontal polarisation with following formula (11) by desired efficient light sources zone _h(Ave), can define average specific polarizing coefficient RSP with following formula (12) about vertical polarisation _v(Ave).

(11)RSP _h(Ave)＝Ix(Ave)/(Ix+Iy)Ave

＝∑[S ₀(x _i，y _i).RSP _h(x _i，y _i)]/∑S ₀(x _i，y _i)，

(12)RSP _v(Ave)＝Iy(Ave)/(Ix+Iy)Ave

＝∑[S ₀(x _i，y _i).RSP _v(x _i，y _i)]/∑S ₀(x _i，y _i)，

Wherein 1x (Ave) be pass through fixed efficient light sources zone (x _i, y _i) and to arrive the light of a bit (tiny area) on the image planes average in the intensity of directions X polarized component (polarisation of the direction of vibration of directions X on pupil), Iy (Ave) be pass through fixed efficient light sources zone (x _i, y _i) and to arrive the light of a bit (tiny area) on the image planes average in the intensity of Y direction polarized component (polarisation of the direction of vibration of Y direction on pupil), RSP _h(x _i, y _i) be pass through fixed efficient light sources zone (x _i, y _i) and arrive a bit specific polarizing coefficient at horizontal polarisation of the light of (tiny area) on the image planes, RSP _v(x _i, y _i) be pass through fixed efficient light sources zone (x _i, y _i) and arrive the specific polarizing coefficient at vertical polarisation of the light of a bit (tiny area) on the image planes.Again, (Ix+Iy) Ave be pass through the intensity of whole light beams in fixed efficient light sources zone average.

In this, RSP when desirable non-polarizing illumination _h(x _i, y _i), RSP _v(x _i, y _i) the two is 50%, RSP when desirable horizontal polarisation _h(x _i, y _i) be 100%, RSP when desirable vertical polarisation _v(x _i, y _i) be 100%.

Then, correspondence pass through fixed efficient light sources zone (x _i, y _i) and arrive some light beam of (tiny area) on the image planes, can use following formula (13) to define average specific degree of polarization DSP (Ave).

(13)DSP(Ave)＝(Ix-Iy)Ave/(Ix+Iy)Ave

＝{∑[Ix(x _i，y _i)-Iy(x _i，y _i)]/∑[Ix(x _i，y _i)+Iy(x _i，y _i)]}

＝S ₁’(Ave)

＝{∑S ₁/∑S ₀}

In this, (Ix-Iy) Ave be pass through fixed efficient light sources zone (x _i, y _i) and the light beam that arrives a bit (tiny area) on the image planes the intensity of directions X polarized component with on average pass through fixed efficient light sources zone (x _i, y _i) and the light beam that arrives a bit (tiny area) on the image planes the intensity of Y direction polarized component differ average, Ix (x _i, y _i) be pass through fixed efficient light sources zone (x _i, y _i) and arrive the intensity of the light beam of a bit (tiny area) on the image planes at the directions X polarized component, Iy (x _i, y _i) be pass through fixed efficient light sources zone (x _i, y _i) and arrive the intensity of the light beam of a bit (tiny area) on the image planes at Y direction polarized component, S ₁' (Ave) be the efficient light sources zone (x fixed _i, y _i) S ₁' composition average.

In formula (13), DSP (Ave) is 0 when desirable non-polarizing illumination, and DSP (Ave) is 1 when desirable horizontal polarisation, and DSP (Ave) is-1 when desirable vertical polarisation.

Now, the illumination optics device of present embodiment, and then exposure device, fixed efficient light sources zone (x _i, y _i) average specific polarizing coefficient RSP _h(Ave), RSP _v(Ave) satisfy

RSP _h(Ave)＞70％，RSP _v(Ave)＞70％，

Can see be linear polarization in the fixed efficient light sources zone.In this, as average specific polarizing coefficient RSP _h(Ave), RSP _v(Ave) do not satisfy the situation of following formula condition, in the illumination of Zhou Fangxiang polarisation wheel band, or Zhou Fangxiang polarisation quadrupole illuminating, two utmost point illuminations of Zhou Fangxiang polarisation etc., plane of polarisation is arranged because be not desirable linear polarization state in deciding direction, can not upwards promote imaging capability for the thin pattern of the line width that particular orientation (pitch) direction is arranged.

Again, as shown in figure 13, use 4 to cut apart polarization conversion element 10 and carry out 4 situations of cutting apart the illumination of Zhou Fangxiang polarisation wheel band, as shown in figure 20, the secondary souce 31 of wheel belt shape is 4 to cut apart, also can be to the average specific polarizing coefficient RSP of each cut zone 31A1,31A2,31C1,31C2 _h(Ave), RSP _v(Ave) amount of commenting.

Exposure device for the foregoing description, cover curtain (cross mark) (illumination step) by illumination optics device with illumination, by using projection optical system will be formed on pattern that the transfer printing of cover curtain uses, can make microcomponent (semiconductor element, capturing element, liquid crystal display cells, thin-film electro magnetic head etc.) in photonasty base plate exposure (step of exposure).Below, use the exposure device of the foregoing description, forming circuit pattern as the wafer of photonasty substrate etc., and the practical methods that obtains as the semiconductor element of microcomponent is an example, does explanation with reference to the process flow diagram of Figure 21.

At first, in the step 301 of Figure 21, deposited metal film on one batch wafer.In next step 302, on the metal film on these wafers of batch, be coated with photoresist.Afterwards, in step 303, use the exposure device of the foregoing description, the picture that makes the pattern on the cover curtain is by projection optical system, and each shooting area on the wafer of this batch is exposed transfer printing in turn.Afterwards, in step 304, carry out the photoresist developing on the wafer of this batch after, in step 305, carry out etching by the photoresist pattern on the wafer of this batch as the cover curtain, therefore, corresponding cover curtain is gone up the circuit pattern of pattern, is formed on each shooting area of each wafer.Afterwards, by formation of carrying out the circuit pattern on upper strata more etc., make the element of semiconductor element etc. manufactured.Manufacture method according to above-mentioned semiconductor element etc. has the semiconductor element of atomic thin circuit pattern that good production capacity can be arranged.

Again,, utilize on dull and stereotyped (glass substrate) for the exposure device of the foregoing description, form fixed pattern (circuit pattern, electrode pattern etc.), can obtain liquid crystal display cells as microcomponent.Below, with reference to the process flow diagram of Figure 22 as an example explanation.At Figure 22, form step 401 in pattern, use the exposure device of the foregoing description, at the pattern of photonasty substrate (the applied glass substrate that photoresist is arranged etc.) transfer printing exposure cover curtain, so-called micro-photographing process is carried out.Utilize this micro-photographing process step, on the photonasty substrate, contain a plurality of electrodes etc. fixed pattern be formed.Afterwards, the substrate that is exposed utilizes through development step, and etching step removes each step of photoresist step etc., on the substrate fixed pattern be formed, then carry out chromatic filter (color filter) and form step 402.

Form step 402 for chromatic filter, 3 points of corresponding red, green, blue are one group, are formed many rectangular assortments, or 3 light filter of red, green, blue is that an assembly is listed as into a plurality of horizontal scanning line directions, and form chromatic filter.Then, after chromatic filter formed step 402, unit combination step 403 was carried out.In unit combination step 403, be assembled with by pattern and form the resulting substrate of deciding pattern of step 401, and use by chromatic filter and form chromatic filter that step 402 obtains etc., and obtain liquid crystal panel (liquid crystal cells).

Unit combination step 403 for example, is being formed the resulting substrate of deciding pattern of step 401 by pattern, and uses to be formed between the resulting chromatic filter of step 402 by chromatic filter and inject liquid crystal, and manufacturing liquid crystal panel (liquid crystal cells).Afterwards, in the combination step 404 of module, the circuit of the display action of the liquid crystal panel that is combined (liquid crystal cells), each parts of backlight module etc. are installed, and make and finish as liquid crystal display cells.According to the manufacture method of above-mentioned liquid crystal display cells, can obtain the liquid crystal display part of atomic thin circuit pattern, and make it that good production capacity be arranged.

Again, for the foregoing description, as the light of exposure, though use KrF excimer laser light (wavelength 248nm) or ArF excimer laser light (wavelength 193nm), be not limited to this, the light source that other are fit to is for example supplied with the F of the laser light of wavelength 157nm ₂LASER Light Source etc. also can be suitable for the present invention.Moreover for the foregoing description, the exposure device that comprises illumination optics device is that example is done explanation, but covers the general illumination optical devices of curtain or wafer plane of illumination in addition in order to throw light on, and as can be known, also can use the present invention.

In the foregoing description, in the light path between projection optical system and the photonasty substrate, also can use and fill up the method for refractive index more than or equal to 1.1 medium (typical liquid), promptly so-called immersion method again.In this situation, as the method for filling up liquid in the light path between projection optical system and the photonasty substrate, can adopt in international publication number WO99/49504 revealed part to fill up liquid, the platform that Te Kaiping 6-124873 also discloses the substrate that keeps exposure object makes mobile method in liquid bath, Japanese patent laid-open 10-303114 also is disclosed on the platform liquid bath that forms institute's depthkeeping degree, and keeps the method for substrate etc. therein.

Again, as liquid, preferable use can have penetrability and high index of refraction to the light of exposure, and the applied photoresistance of relative projection optical system and substrate surface is the liquid of stabilizing, for example with KrF excimer laser light or ArF excimer laser light situation, can use pure water, deionized water as liquid as the light of exposure.Again, use is as the F of the light of exposure ₂The situation of laser can be used as having of liquid to see through F ₂Laser light, for example the fluorine prime system liquid of fluorine prime system oil or fluorinated polyether (PFPE) etc.

Claims (33)

1. polarization conversion element, be configured in the illumination path of illumination optical apparatus, described illumination optical apparatus is based on the light of linear polarization state and plane of illumination is thrown light on, and described linear polarization state only come from the light source that linear polarization is provided, behind the described polarization conversion element of light incident of described linear polarization state, described polarization conversion element penetrates at Zhou Fangxiang has the light of Zhou Fangxiang polarized condition of polarization direction or the light that has the footpath direction polarized condition of polarization direction in the footpath direction, it is characterized in that it comprises:

Utilize active optical material to form, a thickness distribution that changes at Zhou Fangxiang is arranged; And the polarization direction of the linear polarization of incident is rotated.

2. polarization conversion element according to claim 1, this thickness distribution wherein, be set and make and will the light of linear polarization state of the polarization direction of single direction be arranged, be transformed into the light of Zhou Fangxiang polarized condition of the polarization direction of promising Zhou Fangxiang, or the light in the footpath direction polarized condition of the polarization direction of radial direction is arranged.

3. polarization conversion element according to claim 1 is characterized in that wherein Zhou Fangxiang is divided into a plurality of zones, and the thickness difference in adjacent any 2 zones in those zones.

4. polarization conversion element according to claim 3 is characterized in that wherein relative any 2 zones in those zones, and equal optically-active angle is arranged.

5. polarization conversion element according to claim 4 is characterized in that wherein these relative any 2 zones, and equal thickness is arranged.

6. polarization conversion element according to claim 3 is characterized in that wherein each those zone, is about fan shape.

7. polarization conversion element according to claim 1, it is characterized in that wherein having at Zhou Fangxiang is the continually varying thickness distribution.

8. polarization conversion element according to claim 1, it is characterized in that wherein more comprising do not have optical activity central optical by the zone.

9. polarization conversion element according to claim 8 is characterized in that the size by the radial direction in zone of this central optical wherein, for the radial direction size of the effective coverage of this polarization conversion element more than or equal to 3/10.

10. polarization conversion element according to claim 1 is characterized in that wherein this optical material, is to be formed by the crystalline material that the crystal optics axle is configured to the direct of travel of incident light.

11. polarization conversion element according to claim 1, it is characterized in that wherein this polarization conversion element is arranged to freely to insert from the light path of described incident light takes off.

12. an illumination optical apparatus is characterized in that comprising:

The described polarization conversion element of each of claim 1 to 11, described polarization conversion element is disposed in the optical path of illuminating light.

13. illumination optical apparatus according to claim 12 is characterized in that wherein this polarization conversion element, is configured near the pupil or pupil of this illumination optical apparatus.

14. illumination optical apparatus according to claim 12 is characterized in that wherein more comprising a phase section, is configured in the light path of light incident side of this polarization conversion element, and the polarization direction of the light of corresponding incident linear polarization state is changed.

15. illumination optical apparatus according to claim 14 is characterized in that wherein this phase section has one 1/2 wavelength plates, can rotate freely on the crystal optics axle as the optical axis center of aforementioned illumination optical apparatus.

16. illumination optical apparatus according to claim 14 is characterized in that wherein more comprising one the 2nd phase section, is configured in the light path of light incident side of this phase section, makes the light of the elliptical polarized light state of incident, is transformed into the light of linear polarization state.

17. illumination optical apparatus according to claim 16 is characterized in that wherein the 2nd phase section has one 1/4 wavelength plates, can rotate freely on the crystal optics axle as the optical axis center of aforementioned illumination optical apparatus.

18. illumination optical apparatus according to claim 12, it is characterized in that described polarization conversion element also comprise do not have optical activity central optical by the zone.

19. illumination optical apparatus according to claim 18 is characterized in that the size by the radial direction in zone of this central optical wherein, for the radial direction size of the effective coverage of this polarization conversion element more than or equal to 3/10.

20. illumination optical apparatus according to claim 18 is characterized in that the size by the radial direction in zone of this central optical wherein, for the radial direction size of the effective coverage of this polarization conversion element more than or equal to 1/3.

21. illumination optical apparatus according to claim 18 is characterized in that wherein more comprising and takes turns band than the change optical system, is formed on the wheel band ratio of secondary souce of the pupil of this illumination optical apparatus with change.

22. illumination optical apparatus according to claim 21 is characterized in that wherein this polarization conversion element, is configured in this light source and this and takes turns band than in the light path between the change optical system, satisfies:

(10in+ΔA)/10out＜0.75

0.4＜(10in+ΔA)/10out，

Wherein

10in: the central optical of this polarization conversion element is passed through the effective radius in zone,

10out: the outside effective radius of this polarization conversion element,

Δ A: take turns the increase part of band than the inner radius of the light beam of change optical system by this.

23. illumination optical apparatus according to claim 12 is characterized in that wherein this optical material, is to be formed by the crystalline material that the crystal optics axle is configured to the direct of travel of incident light.

24. an exposure device is characterized in that comprising:

The described illumination optical apparatus of claim 12, and by this illumination optical apparatus with fixed pattern exposure to the photonasty substrate.

25. an exposure method is characterized in that comprising:

Use the described illumination optical apparatus of claim 12, with fixed pattern exposure to the photonasty substrate.

26. a manufacturing method is characterized in that comprising:

Use the described illumination optical apparatus of claim 12, with the fixed pattern exposure step to the photonasty substrate; And

The step that the described photonasty substrate that has exposed is carried out video picture.

27. method of making polarization conversion element, be that linear polarization state transformation Cheng Zaizhou direction with incident light has the Zhou Fangxiang polarized condition of change state or has the manufacture method of polarization conversion element of the footpath direction change state of polarization direction in the footpath direction, it is characterized in that comprising:

Prepare active optical material; And

Set the thickness distribution that this optical material changes at Zhou Fangxiang.

28. the method for manufacturing polarization conversion element according to claim 27, it is characterized in that wherein this thickness distribution is set, make the light of the linear polarization state of the polarization direction that single direction will be arranged, be transformed into the light of Zhou Fangxiang polarized condition of the polarization direction of promising Zhou Fangxiang, or the light in the footpath direction polarized condition of the polarization direction of radial direction is arranged.

29. the method for manufacturing polarization conversion element according to claim 27, it is characterized in that wherein this is set in the step of the thickness distribution of Zhou Fangxiang variation, be in the divided a plurality of zones of Zhou Fangxiang, set the different thickness distribution of thickness that makes adjacent any 2 zones.

30. the method for manufacturing polarization conversion element according to claim 29 is characterized in that wherein in those zones, there is identical optically-active angle in relative any 2 zones.

31. the method for manufacturing polarization conversion element according to claim 30 is characterized in that there is identical thickness in wherein relative any 2 zones.

32. the method for manufacturing polarization conversion element according to claim 27 is characterized in that wherein this is set in the step of the thickness distribution of Zhou Fangxiang variation, is to be set in Zhou Fangxiang continually varying thickness distribution.

33. according to the method for each described manufacturing polarization conversion element of claim 27 to 32, wherein prepare this step of active optical material, it is the direct of travel of incident light that this optical material is set crystal optics axle.

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