JP2010129719A - Light flux conversion element, illumination optical system, exposure device, and method for manufacturing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illumination optical system for adjusting the balance of light intensity between one two-pole-form region and the other two-pole-form region in a four-pole-form pupil intensity distribution, for example. <P>SOLUTION: This illumination optical system (1 to 7) that illuminates a surface to be irradiated (W; W) with light from a light source (LS) includes: a light flux conversion element (2), and a distribution formation optical system (3, 4) that forms a predetermined light intensity distribution on a light pupil based on light via the light flux conversion element. The light flux conversion element includes a plurality of kinds of unit regions that form in a far field region light fluxes with mutually different light intensity distributions based on each light flux entered. The plurality of kinds of unit regions are arranged so that the light intensity distribution of an optical region may change, without changing the outline form of a light region, according to the change of the position of incoming light fluxes against the light flux conversion element. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light beam conversion element, an illumination optical system, an exposure apparatus, and a device manufacturing method. More specifically, the present invention relates to an illumination optical system suitable for an exposure apparatus for manufacturing devices such as a semiconductor element, an image sensor, a liquid crystal display element, and a thin film magnetic head in a lithography process.

  In a typical exposure apparatus of this type, a light beam emitted from a light source is passed through a fly-eye lens as an optical integrator, and a secondary light source (generally an illumination pupil) as a substantial surface light source composed of a number of light sources. A predetermined light intensity distribution). Hereinafter, the light intensity distribution in the illumination pupil is referred to as “pupil intensity distribution”. The illumination pupil is a position where the illumination surface becomes the Fourier transform plane of the illumination pupil by the action of the optical system between the illumination pupil and the illumination surface (a mask or a wafer in the case of an exposure apparatus). Defined.

  The light beam from the secondary light source is condensed by the condenser lens and then illuminates the mask on which a predetermined pattern is formed in a superimposed manner. The light transmitted through the mask forms an image on the wafer via the projection optical system, and the mask pattern is projected and exposed (transferred) onto the wafer. The pattern formed on the mask is highly integrated, and it is indispensable to obtain a uniform illumination distribution on the wafer in order to accurately transfer the fine pattern onto the wafer.

  Conventionally, there has been proposed an illumination optical system that performs modified illumination such as annular illumination or multipolar illumination (bipolar illumination, quadrupole illumination, etc.) by controlling the position of the incident light beam with respect to the diffractive optical element (Patent Literature). 1).

JP 2006-5319 A

  In the illumination optical system disclosed in Patent Document 1, for example, when performing quadrupole illumination by forming a quadrupole pupil intensity distribution, if the position of the incident light beam with respect to the diffractive optical element is displaced from a desired position, 4 In the polar pupil intensity distribution, the difference between the light intensity of the bipolar area spaced in the first direction across the optical axis and the light intensity of the bipolar area spaced in the second direction Is likely to occur greatly. As a result, when this illumination optical system is applied to an exposure apparatus, the mask pattern is photosensitive due to an imbalance in light intensity between one bipolar region and the other bipolar region. There is a possibility that a desired line width may not be formed at a desired position on the substrate.

  The present invention has been made in view of the above-described problems. For example, the balance of light intensity between one bipolar region and the other bipolar region in a quadrupole pupil intensity distribution is adjusted. It is an object of the present invention to provide an illumination optical system that can do this. In addition, the present invention uses an illumination optical system that adjusts the balance of light intensity between one dipole region and the other dipole region in a quadrupole pupil intensity distribution, for example. An object of the present invention is to provide an exposure apparatus capable of performing good exposure under illumination conditions.

In order to solve the above problems, in the first embodiment of the present invention, there is provided a light beam conversion element that converts an incident light beam to form a light region having an outer shape different from the incident light beam in a far field region,
A plurality of first unit regions for forming a light beam having a first light intensity distribution in the far field region;
A plurality of second unit regions for forming a light beam having a second light intensity distribution different from the first light intensity distribution in the far field region;
There is provided a light beam conversion element, wherein at least one second unit region is located between the plurality of first unit regions.

According to a second aspect of the present invention, there is provided a light beam conversion element that converts an incident light beam and forms a light region having an outer shape different from the incident light beam in a far field region,
A plurality of types of unit regions for forming light beams with different light intensity distributions in the far field region based on each incident light beam,
The plurality of types of unit regions are arranged such that the light intensity distribution of the light region changes without changing the outer shape of the light region according to a change in the position of the incident light beam with respect to the light beam conversion element. There is provided a light beam conversion element characterized in that:

In the third embodiment of the present invention, in the illumination optical system that illuminates the illuminated surface with light from the light source,
A light beam conversion element of the first form or the second form;
There is provided an illumination optical system comprising: a distribution forming optical system that forms a predetermined light intensity distribution in an illumination pupil of the illumination optical system based on light that has passed through the light beam conversion element.

  According to a fourth aspect of the present invention, there is provided an exposure apparatus comprising the illumination optical system according to the third aspect for illuminating a predetermined pattern, and exposing the predetermined pattern onto a photosensitive substrate.

In the fifth embodiment of the present invention, using the exposure apparatus of the fourth embodiment, an exposure step of exposing the predetermined pattern to the photosensitive substrate;
Developing the photosensitive substrate to which the predetermined pattern is transferred, and forming a mask layer having a shape corresponding to the predetermined pattern on the surface of the photosensitive substrate;
And a processing step of processing the surface of the photosensitive substrate through the mask layer.

  An illumination optical system according to an aspect of the present invention includes a light beam conversion element that converts a rectangular incident light beam to form a quadrupole light region in the far field region, and thus forms a quadrupole pupil intensity distribution. I have. In this light beam conversion element, a plurality of types of unit regions that form quadrupolar light beams having the same outer shape and different light intensity distributions in the far field region based on each incident light beam have a required distribution. Arranged according to morphology. As a result, the change in the position of the incident light beam with respect to the light beam conversion element and the change in the intensity difference between one bipolar region and the other bipolar region in the quadrupole pupil intensity distribution are set in a desired relationship. Is possible.

  Therefore, in the illumination optical system of the present invention, for example, it is possible to stably adjust the light intensity balance between one bipolar region and the other bipolar region in a quadrupole pupil intensity distribution. it can. In the exposure apparatus of the present invention, for example, an illumination optical system that stably adjusts the light intensity balance between one bipolar region and the other bipolar region in a quadrupole pupil intensity distribution. Can be used to perform good exposure under appropriate illumination conditions, and thus a good device can be manufactured.

  Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a drawing schematically showing a configuration of an exposure apparatus according to an embodiment of the present invention. In FIG. 1, the Z axis along the normal direction of the exposure surface (transfer surface) of the wafer W, which is a photosensitive substrate, and the Y axis in the direction parallel to the paper surface of FIG. In the W exposure plane, the X axis is set in a direction perpendicular to the paper surface of FIG.

  Referring to FIG. 1, in the exposure apparatus of the present embodiment, exposure light (illumination light) is supplied from a light source LS. As the light source LS, for example, an ArF excimer laser light source that supplies light with a wavelength of 193 nm, a KrF excimer laser light source that supplies light with a wavelength of 248 nm, or the like can be used. A light beam emitted from the light source LS is incident on the diffractive optical element 2 via the beam transmission unit 1. The beam transmitter 1 guides the incident light beam from the light source LS to the diffractive optical element 2 while converting it into a light beam having an appropriate size and shape, and changes the position and angle of the light beam incident on the diffractive optical element 2. It has a function of actively correcting fluctuations.

  In general, a diffractive optical element is formed by forming a step having a pitch of the wavelength of exposure light (illumination light) on a substrate, and has a function of diffracting an incident beam to a desired angle. Specifically, the diffractive optical element 2 has a light intensity distribution having a desired outer shape different from the incident light beam in the far field (or Fraunhofer diffraction region), for example, when a parallel light beam having a rectangular cross section is incident. It has the function to form. That is, the diffractive optical element 2 is a light beam conversion element that converts an incident light beam and forms a light region having an outer shape different from that of the incident light beam in the far field region. Hereinafter, in order to facilitate understanding of the description, it is assumed that the diffractive optical element 2 is a diffractive optical element for quadrupole illumination that forms a quadrupole light region in the far field region. A specific configuration and operation of the diffractive optical element 2 will be described later.

  The light beam incident on the diffractive optical element 2 for quadrupole illumination is optically transmitted through a zoom lens 3 for varying σ value (σ value = mask-side numerical aperture of illumination optical system / mask-side numerical aperture of projection optical system). The light enters the micro fly's eye lens (or fly eye lens) 4 as an integrator. The micro fly's eye lens 4 is, for example, an optical element made up of a large number of micro lenses having positive refractive power arranged vertically and horizontally and densely, by performing etching treatment on a plane-parallel plate to form a micro lens group. It is configured.

  Each micro lens constituting the micro fly's eye lens is smaller than each lens element constituting the fly eye lens. Further, unlike a fly-eye lens composed of lens elements isolated from each other, a micro fly-eye lens is formed integrally with a large number of micro lenses (micro refractive surfaces) without being isolated from each other. However, the micro fly's eye lens is the same wavefront division type optical integrator as the fly eye lens in that lens elements having positive refractive power are arranged vertically and horizontally. For example, a cylindrical micro fly's eye lens can be used as the micro fly's eye lens 4. The configuration and action of the cylindrical micro fly's eye lens are disclosed in, for example, US Pat. No. 6,913,373.

  The diffractive surface of the diffractive optical element 2 is disposed at or near the front focal position of the zoom lens 3, and the incident surface of the micro fly's eye lens 4 is disposed at or near the rear focal position of the zoom lens 3. In other words, in the zoom lens 3, the diffractive surface of the diffractive optical element 2 and the incident surface of the micro fly's eye lens 4 are arranged substantially in a Fourier transform relationship. Therefore, for example, a quadrupole illumination field centered on the optical axis AX is formed on the incident surface of the micro fly's eye lens 4. The overall shape of the quadrupole illumination field changes in a similar manner depending on the focal length of the zoom lens 3. Each micro lens constituting the micro fly's eye lens 4 has a rectangular cross section similar to the shape of the illumination field to be formed on the mask M (and thus the shape of the exposure region to be formed on the wafer W).

  A light beam incident on the micro fly's eye lens 4 is two-dimensionally divided by a large number of microlenses, and an illumination beam formed by the incident light beam is formed on the rear focal plane (and thus the position of the illumination pupil) as shown in FIG. A secondary light source (pupil intensity distribution) 20 composed of a secondary light source having substantially the same light intensity distribution as the field, that is, a quadrupole substantial surface light source centered on the optical axis AX is formed. Referring to FIG. 2, a quadrupole pupil intensity distribution 20 formed in the illumination pupil is, for example, a pair of arcuate substantial surface light sources (hereinafter referred to as “X” direction) with an optical axis AX interposed therebetween. 20a and 20b) and a pair of arc-shaped substantial surface light sources 20c and 20d spaced apart in the Z direction across the optical axis AX.

  The light beam from the secondary light source formed on the rear focal plane of the micro fly's eye lens 4 illuminates the mask blind 6 in a superimposed manner after passing through the condenser optical system 5. Thus, a rectangular illumination field corresponding to the shape and focal length of each microlens constituting the micro fly's eye lens 4 is formed on the mask blind 6 as an illumination field stop. The light flux that has passed through the rectangular opening (light transmitting portion) of the mask blind 6 receives the light condensing action of the imaging optical system 7 and then illuminates the mask M on which a predetermined pattern is formed in a superimposed manner.

  That is, the imaging optical system 7 forms an image of the rectangular opening of the mask blind 6 on the mask M held on the mask stage MS. The light flux that has passed through the pattern of the mask M forms an image of the mask pattern on the wafer (photosensitive substrate) W held on the wafer stage WS via the projection optical system PL. Thus, by performing batch exposure or scan exposure while driving and controlling the wafer W two-dimensionally in a plane (XY plane) orthogonal to the optical axis AX of the projection optical system PL, each exposure region of the wafer W is masked. M patterns are sequentially exposed.

  The exposure apparatus of the present embodiment is based on the pupil distribution measurement unit DT that measures the pupil intensity distribution on the pupil plane of the projection optical system PL based on the light via the projection optical system PL, and the measurement result of the pupil distribution measurement unit DT. And a controller CR that controls the position of the diffractive optical element 2 along the XZ plane. That is, the diffractive optical element 2 is movable along the XZ plane by the action of the drive unit DR based on a command from the control unit CR, and the relative position between the diffractive optical element 2 and the incident light beam is variably configured. Yes.

  The pupil distribution measurement unit DT includes a CCD imaging unit having an imaging surface disposed at a position optically conjugate with the pupil position of the projection optical system PL, for example, and pupil intensity distribution regarding each point on the image plane of the projection optical system PL (Pupil intensity distribution formed by light incident on each point at the pupil position of the projection optical system PL) is monitored. For details of the configuration and operation of the pupil distribution measurement unit DT, reference can be made to, for example, US Patent Publication No. 2008/0030707.

  In the present embodiment, as described above, the secondary light source formed by the micro fly's eye lens 4 is used as a light source, and the mask M arranged on the irradiated surface of the illumination optical system (1-7) is Koehler illuminated. For this reason, the position where the secondary light source is formed is optically conjugate with the position of the aperture stop AS of the projection optical system PL, and the formation surface of the secondary light source is the illumination pupil plane of the illumination optical system (1-7). Can be called. Typically, the irradiated surface (the surface on which the mask M is disposed or the surface on which the wafer W is disposed when the illumination optical system including the projection optical system PL is considered) is optical with respect to the illumination pupil plane. A Fourier transform plane.

  The pupil intensity distribution is a light intensity distribution (luminance distribution) on the illumination pupil plane of the illumination optical system (1-7) or a plane optically conjugate with the illumination pupil plane. When the number of wavefront divisions by the micro fly's eye lens 4 is relatively large, the overall light intensity distribution formed on the incident surface of the micro fly's eye lens 4 and the overall light intensity distribution (pupil intensity distribution) of the entire secondary light source. ) And a high correlation. For this reason, the light intensity distribution on the incident surface of the micro fly's eye lens 4 and a surface optically conjugate with the incident surface can also be referred to as a pupil intensity distribution. In the configuration of FIG. 1, the zoom lens (condensing optical system) 3 and the micro fly's eye lens 4 illuminate the illumination optical systems (1 to 7) based on light through the diffractive optical element 2 as a light beam conversion element. A distribution forming optical system that forms a predetermined light intensity distribution in the pupil is configured.

  FIG. 3 is a diagram schematically showing a main configuration of the diffractive optical element of the present embodiment. In FIG. 3, the local coordinates (x, y, z) corresponding to the overall coordinates (X, Y, Z) are set with the center of the diffractive optical element 2 as the origin. Referring to FIG. 3, the diffractive optical element 2 includes a large number of rectangular unit diffraction regions A that are densely arranged vertically and horizontally along the xz plane. Specifically, the diffractive optical element 2 includes, for example, 2n + 1 (n is a positive integer) types of unit diffraction areas A0, A + 1, A-1, A + 2, A-2,..., A + n, An. Yes.

  However, in FIG. 3, for the sake of clarity, the two unit diffraction areas A that should be adjacent to each other are slightly separated from each other and the y-axis display is omitted. Also, the configuration of the central portion of the diffractive optical element 2, that is, only the central portion including the seven types of unit diffraction areas A0, A + 1, A-1, A + 2, A-2, A + 3, and A-3 is shown. The large number of unit diffraction regions A are formed, for example, on the light incident side surface of the diffractive optical element 2. However, a large number of these unit diffraction regions A may be formed on the light exit side surface of the diffractive optical element 2, or the unit diffraction regions formed on the entrance surface and the unit diffraction regions formed on the exit surface. May be mixed.

  Regardless of the type, each unit diffraction region A has a function of forming a quadrupolar light beam 21 having the same outer shape in the far field region as shown in FIG. The quadrupolar light beam 21 is composed of a pair of arc-shaped light beams 21a and 21b spaced apart in the X direction across the optical axis AX and a pair of arc shaped light beams spaced apart in the Z direction across the optical axis AX. And light beams 21c and 21d. As a result, the light beam that has passed through the plurality of unit diffraction regions A of the diffractive optical element 2 is superimposed on the incident surface of the micro fly's eye lens 4, and the quadrupole pupil shown in FIG. An intensity distribution 20 is formed.

  Hereinafter, for ease of explanation, each unit diffraction region A forms a pair of light beams 21a and 21b having the same light intensity Iab and a pair of light beams 21c and 21d having the same light intensity Icd. And In the quadrupolar light beam 21 formed by the unit diffraction region A0, the light intensity Iab of the pair of light beams 21a and 21b is equal to the light intensity Icd of the pair of light beams 21c and 21d. In the quadrupolar light beam 21 formed by the unit diffraction region A + n, the light intensity Icd of the pair of light beams 21c and 21d is assumed to be n% larger than the light intensity Iab of the pair of light beams 21a and 21b.

  On the other hand, in the quadrupolar light beam 21 formed by the unit diffraction region An, the light intensity Icd of the pair of light beams 21c and 21d is n% smaller than the light intensity Iab of the pair of light beams 21a and 21b. . That is, generally, in the quadrupolar light beam 21 formed by the unit diffraction areas A ± i (i = 0 to n), the light intensity Icd of the pair of light beams 21c and 21d and the light of the pair of light beams 21a and 21b. When the difference Icd−Iab from the intensity Iab is Is, it is assumed that Is / Iab is ± i%.

  Referring to FIG. 3 again, the region for one row extending in the horizontal direction in FIG. 3 including the unit diffraction region at the center of the diffractive optical element 2 (the position of x = z = 0), that is, the region of the 0th row is The unit diffraction regions A-1, A0, and A + 1 are included so that the average diffraction effect is substantially equal to the diffraction effect of the unit diffraction region A0. Further, in the region of the 0th row, the unit diffraction regions A-1, A0, A + 1 are dominant, for example, at least one unit diffraction region A + 1 or A-1 is located between the two unit diffraction regions A0, At least one unit diffraction region A0 is located between the two unit diffraction regions A + 1 or between the two unit diffraction regions A-1. In other words, in the area of the 0th row, three types of unit diffraction areas A-1, A0, A + 1 are alternately arranged.

  The region in the + 1st row adjacent to the upper side of the region in the 0th row in FIG. 3 includes many unit diffraction regions A0, A + 1, A + 2, and the average diffraction effect is substantially equal to the diffraction effect in the unit diffraction region A + 1. It is configured as follows. In the area of the + 1st row, the unit diffraction areas A0, A + 1, and A + 2 are dominant. For example, at least one unit diffraction area A0 or A + 2 is located between the two unit diffraction areas A + 1, and two unit diffraction areas. At least one unit diffraction region A + 1 is located between the regions A0 or between the two unit diffraction regions A + 2. In other words, three types of unit diffraction areas A0, A + 1, A + 2 are alternately arranged in the area of the + 1st row.

  Similarly, the + 2nd row region adjacent to the upper side in FIG. 3 of the + 1st row region includes many unit diffraction regions A + 1, A + 2, and A + 3, and the average diffraction effect thereof is the same as the diffraction effect of the unit diffraction region A + 2. It is comprised so that it may become substantially equal. In the + 2nd row region, the unit diffraction regions A + 1, A + 2, and A + 3 are dominant. For example, at least one unit diffraction region A + 1 or A + 3 is located between the two unit diffraction regions A + 2, and two unit diffraction regions are included. At least one unit diffraction region A + 2 is located between the regions A + 1 or between the two unit diffraction regions A + 3. That is, in the area of the + 2nd row, three types of unit diffraction areas A + 1, A + 2, and A + 3 are alternately arranged.

  On the other hand, the region of the -1st row adjacent to the lower side of the 0th row region in FIG. 3 includes many unit diffraction regions A0, A-1 and A-2, and the average diffraction effect thereof is the unit diffraction region. The diffraction effect of A-1 is substantially equal. Further, in the region of the -1st row, the unit diffraction regions A0, A-1, A-2 are dominant, and for example, at least one unit diffraction region A0 or A- between two unit diffraction regions A-1. 2 is located, and at least one unit diffraction region A-1 is located between the two unit diffraction regions A0 or between the two unit diffraction regions A-2. That is, three types of unit diffraction regions A0, A-1, and A-2 are alternately arranged in the region of the -1st row.

  Similarly, the region in the second row adjacent to the lower side in FIG. 3 of the region in the first row includes many unit diffraction regions A-1, A-2, A-3, and the average diffraction effect thereof. Is configured to be substantially equal to the diffraction effect of the unit diffraction region A-2. In the region of the -2nd row, the unit diffraction regions A-1, A-2, A-3 are dominant, and for example, at least one unit diffraction region A- between two unit diffraction regions A-2. 1 or A-3 is located, and at least one unit diffraction region A-2 is located between two unit diffraction regions A-1 or between two unit diffraction regions A-3. That is, in the region of the -2nd row, three types of unit diffraction regions A-1, A-2, A-3 are alternately arranged.

  That is, in general, the region of the ± jth (j = 0 to m; m <n) rows includes many unit diffraction regions A ± (j−1), A ± j, A ± (j + 1), The average diffraction effect is configured to be substantially equal to the diffraction effect of the unit diffraction regions A ± j. In the ± j-th row area, three types of unit diffraction areas A ± (j−1), A ± j, and A ± (j + 1) are alternately arranged. Further, in the diffractive optical element 2, for example, a unit diffraction region is formed so that the average diffraction effect of the region corresponding to one column extending in the vertical direction in FIG. 3 is substantially constant without depending on the x coordinate position. It is configured to be substantially equal to the diffraction effect of A0.

  As described above, in the diffractive optical element 2, the plurality of types of unit diffraction regions A include the light intensity Icd of the pair of light beams 21 c and 21 d and the pair of light beams 21 a and 21 b in the quadrupolar light beam 21 formed by each unit diffraction region. Are arranged in accordance with the intensity difference Is from the light intensity Iab. Macroscopically, the plurality of types of unit diffraction areas A are arranged along the z direction in the order in which the intensity difference Is in the quadrupolar light beam 21 formed by each unit diffraction area changes monotonously.

  Therefore, as shown in FIG. 5, in a reference state where the center of the diffractive optical element 2 coincides with the optical axis AX, if a rectangular light beam LT centering on the optical axis AX is incident on the diffractive optical element 2, In a quadrupole pupil intensity distribution 20 formed by light passing through the optical element 2 on the illumination pupil of the rear focal plane of the micro fly's eye lens 4, the light intensity I1 of the pair of surface light sources 20a and 20b and the pair of surface light sources 20c. , 20d is almost equal to the light intensity I2. Next, when the diffractive optical element 2 is moved in the −Z direction by the z-direction dimension of the unit diffraction region A by the action of the driving unit DR, the light intensity I2 of the pair of surface light sources 20c and 20d is changed to the pair of surface light sources 20a. , 20b, a quadrupole pupil intensity distribution 20 that is 1% greater than the light intensity I1 is obtained.

  On the other hand, when the diffractive optical element 2 is moved from the reference state in the + Z direction by the dimension in the z direction of the unit diffraction region A, the light intensity I2 of the pair of surface light sources 20c and 20d is greater than the light intensity I1 of the pair of surface light sources 20a and 20b. A quadrupole pupil intensity distribution 20 that is smaller by 1% is also obtained. That is, generally, when the diffractive optical element 2 is moved from the reference state in the −Z direction by a distance of ± j (j = 0 to m; m <n) times the z-direction dimension of the unit diffraction region A, A quadrupole pupil intensity distribution 20 in which the light intensity I2 of the surface light sources 20c and 20d is larger than the light intensity I1 of the pair of surface light sources 20a and 20b by ± j% is obtained.

  As described above, the diffractive optical element 2 of the present embodiment forms a quadrupolar light beam 21 having the same outer shape and different light intensity distributions in the far field region based on each incident light beam. A plurality of unit diffraction areas A are provided. These plural types of unit diffraction areas A are formed in a superimposed manner on the incident surface of the micro fly's eye lens 4 as a far field area according to the change in the position along the Z direction of the incident light beam LT with respect to the diffractive optical element 2. Specifically, the pair of regions 21′c and 21 ′ in the quadrupolar light region 21 ′ is changed so that the light intensity distribution changes without changing the outer shape of the quadrupole light region 21 ′. It arrange | positions so that the intensity difference of d and a pair of area | region 21'a, 21'b may change.

  The quadrupole optical region 21 ′ and the regions 21′a to 21′d of the respective poles are not shown, but the quadrupolar optical region 21 ′ formed in a superimposed manner is the quadrupolar shape shown in FIG. The regions 21'a to 21'd of the respective poles correspond to the light beams 21a to 21d of the respective poles in FIG. As a result, the quadrupole pupil intensity distribution 20 formed on the illumination pupil of the rear focal plane of the micro fly's eye lens 4 according to the change in the position along the Z direction of the incident light beam LT with respect to the diffractive optical element 2. The intensity difference between the pair of surface light sources 20c and 20d and the pair of surface light sources 20a and 20b in the quadrupole pupil intensity distribution 20 changes without changing the outer shape. In other words, by changing the position along the Z direction of the incident light beam LT with respect to the diffractive optical element 2, the pair of surface light sources 20c and 20d and the pair of surface light sources 20a and 20b in the quadrupole pupil intensity distribution 20 The light intensity balance between the two can be adjusted.

  Moreover, in the present embodiment, as is apparent from the above description, the z-direction dimension of the unit diffraction region A, which is the unit change amount of the position of the incident light beam LT with respect to the diffractive optical element 2, and the pair of regions 21′c, 21 'd and the unit change rate of the intensity difference between the pair of regions 21'a and 21'b (that is, the unit change rate of the intensity difference between the pair of surface light sources 20c and 20d and the pair of surface light sources 20a and 20b), It is possible to set a desired relationship according to various design examples. As a result, in the present embodiment, even if the position of the incident light beam LT with respect to the diffractive optical element 2 is changed relatively large along the Z direction, one of the dipolar surface light sources 20c in the quadrupolar pupil intensity distribution 20 is obtained. , 20d and the other dipolar surface light sources 20a, 20b can be changed relatively small.

  Thus, in the illumination optical system (1 to 7) of the present embodiment, the control unit CR refers to the measurement result of the pupil distribution measurement unit DT and outputs a command to the drive unit DR, and the drive unit DR outputs from the control unit CR. By moving the diffractive optical element 2 by a required distance along the Z direction according to the command, one of the two-polar surface light sources 20c and 20d and the other two-polar surface light source in the quadrupole pupil intensity distribution 20 are obtained. The balance of light intensity between 20a and 20b can be adjusted stably. That is, the control unit CR controls the position of the incident light beam LT with respect to the diffractive optical element 2 based on the measurement result of the pupil distribution measurement unit DT, so that the light intensity of one of the bipolar surface light sources 20c and 20d and the other The dipole surface light sources 20a and 20b are adjusted so that their light intensities are substantially equal.

  Alternatively, the control unit CR controls the position of the incident light beam LT with respect to the diffractive optical element 2, so that the light intensity of the one bipolar surface light source 20 c, 20 d and the other bipolar surface light source 20 a, 20 b are controlled. Adjust the light intensity to the required ratio. That is, the control unit CR can adjust the quadrupole pupil intensity distribution 20 to a required distribution by controlling the position of the incident light beam LT with respect to the diffractive optical element 2. Therefore, in the exposure apparatus (2 to WS) of the present embodiment, between the one bipolar surface light source 20c, 20d and the other bipolar surface light source 20a, 20b in the quadrupole pupil intensity distribution 20. By using the illumination optical system (1-7) that stably adjusts the balance of the light intensity of the light, good exposure can be performed under appropriate illumination conditions.

  In the above-described embodiment, the relative position of the incident light beam LT with respect to the diffractive optical element 2 is controlled by moving the diffractive optical element 2 along the XZ plane. However, the present invention is not limited to this, and instead of moving the diffractive optical element 2 or in addition to the movement of the diffractive optical element 2, the position of the light beam LT incident on the diffractive optical element 2 by controlling the beam transmission system 1. Can be changed along the XZ plane, and as a result, the relative position of the incident light beam LT with respect to the diffractive optical element 2 can be changed.

  Further, in the above-described embodiment, each of the plurality of types of unit diffraction areas A provided in the diffractive optical element 2 has the same outer shape based on the incident light beam and has four different light intensity distributions. A light beam 21 is formed in the far field region. In other words, in the diffractive optical element 2 that converts the incident light beam to form a quadrupole optical region 21 ′ different from the incident light beam in the far field region, each unit diffraction region A is based on the incident light beam. A quadrupolar light beam 21 having the same outer shape as the quadrupole light region 21 ′ is formed in the far field region.

  However, the present invention is not limited to this, and the outer shape of the light region that the diffractive optical element as the light beam conversion element should form in the far field region and the light beam formed by each of the plurality of types of unit diffraction regions in the far field region. Regarding the relationship with the outer shape, various forms are possible. Also, various forms are possible for the outer shape, diffraction characteristics, arrangement, etc. of the plurality of types of unit diffraction regions.

  As an example, a unit diffraction region B that forms one of the four polar light beams in the far field region based on each incident light beam, and the other dipolar light beam in the far field region. A mixed type diffractive optical element in which unit diffraction regions C to be formed are mixed is also possible. FIG. 6 is a diagram schematically illustrating a main configuration of a mixed diffractive optical element according to a modification of the present embodiment. Also in FIG. 6, the local coordinates (x, y, z) corresponding to the overall coordinates (X, Y, Z) are set with the center of the diffractive optical element 2A as the origin.

  Referring to FIG. 6, the diffractive optical element 2 </ b> A according to the modification is roughly provided with two types of unit diffraction regions B and C. Regardless of the type, the unit diffraction region B has a function of forming one dipolar light beam 21a, 21b of the quadrupolar light beam 21 shown in FIG. 4 in the far field region. Regardless of the type, the unit diffraction region C has a function of forming the other dipolar light beams 21c and 21d in the far field region. As a result, the light beam passing through the plurality of unit diffraction regions B and C of the diffractive optical element 2A has a quadrupole pupil intensity distribution 20 shown in FIG. 2 on the illumination pupil on the rear focal plane of the micro fly's eye lens 4. Form.

  Hereinafter, in order to facilitate the description, in the dipolar light beams 21a and 21b formed by the unit diffraction regions B ± i (i = 0 to n), the light intensity Ia of one light beam 21a and the other light beam 21b It is assumed that Is / Ib is ± i%, where Is is the difference Ia−Ib from the light intensity Ib of Is. Further, in the bipolar light beams 21c and 21d formed by the unit diffraction regions C ± i (i = 0 to n), the difference Ic between the light intensity Ic of one light beam 21c and the light intensity Id of the other light beam 21d. When Id is Is, Is / Id is ± i%.

  In the diffractive optical element 2A, of the four regions divided by the x axis and the z axis, the region R1 defined by the + x axis and the + z axis includes many unit diffraction regions B + i, and is defined by the + x axis and the −z axis. The region R2 includes many unit diffraction regions Bi. Further, the region R3 defined by the −x axis and the + z axis includes many unit diffraction regions C + i, and the region R4 defined by the −x axis and the −z axis includes many unit diffraction regions Ci.

  Of the region R1 including the unit diffraction region B + i, the 0th region R10 closest to the center includes many unit diffraction regions B-1, B0, and B + 1, and the average diffraction effect is the diffraction effect of the unit diffraction region B0. It is comprised so that it may become substantially equal. In the region R10, for example, at least one unit diffraction region B + 1 or B-1 is located between two unit diffraction regions B0, and between two unit diffraction regions B + 1 or between two unit diffraction regions B-1. At least one unit diffraction region B0 is located in the region. That is, in the region R10, three types of unit diffraction regions B-1, B0, B + 1 are alternately arranged. The same is true in the other regions R1j, R2j, R3J, R4j (j = 0 to m; m <n), which will be described later.

  In general, the j-th region R1j includes many unit diffraction regions B + (j−1), B + j, and B + (j + 1), and the average diffraction effect is almost equal to the diffraction effect of the unit diffraction region B + j. It is comprised so that it may become. That is, in the region R1, the dipole beams 21a and 21b formed by the unit diffraction regions B are arranged according to the intensity difference Is between the light intensity Ia of one light beam 21a and the light intensity Ib of the other light beam 21bb. ing. Macroscopically, the plurality of types of unit diffraction regions B are arranged along the radial direction from the center in the order in which the intensity difference Is in the dipolar light beams 21a and 21b formed by each unit diffraction region changes monotonously. It is arranged. This also applies to other regions R2, R3, and R4 described later.

  Of the region R2 including the unit diffraction region Bi, the 0th region R20 closest to the center includes many unit diffraction regions B-1, B0, and B + 1 as in the region R10, and the average diffraction effect thereof. Is substantially equal to the diffraction effect of the unit diffraction region B0. In general, the j-th region R2j includes many unit diffraction regions B- (j-1), B-j, and B- (j + 1), and the average diffraction effect thereof is the unit diffraction region B-j. The diffraction effect is substantially the same.

  Of the region R3 including the unit diffraction region C + i, the 0th region R30 closest to the center includes many unit diffraction regions C-1, C0, and C + 1, and the average diffraction effect is the diffraction effect of the unit diffraction region C0. It is comprised so that it may become substantially equal. In general, the j-th region R3j includes many unit diffraction regions C + (j−1), C + j, and C + (j + 1), and the average diffraction effect is almost equal to the diffraction effect of the unit diffraction region C + j. It is comprised so that it may become.

  Of the region R4 including the unit diffraction region C-i, the 0th region R40 closest to the center includes many unit diffraction regions C-1, C0, and C + 1 similarly to the region R30, and the average diffraction effect thereof. Is substantially equal to the diffraction effect of the unit diffraction region C0. In general, the jth region R4j includes many unit diffraction regions C- (j-1), Cj, C- (j + 1), and the average diffraction effect thereof is the unit diffraction region Cj. The diffraction effect is substantially the same.

  Therefore, in a reference state in which the center of the diffractive optical element 2A coincides with the optical axis AX, when a rectangular light beam LT centering on the optical axis AX is incident on the diffractive optical element 2A, light passing through the diffractive optical element 2A is emitted. In the quadrupole pupil intensity distribution 20 formed on the illumination pupil on the rear focal plane of the micro fly's eye lens 4, the light intensity is substantially equal between the surface light sources 20a, 20b, 20c, and 20d. When the diffractive optical element 2A is moved in the −Z direction from the reference state, a quadrupolar shape having a property that the light intensity of the surface light sources 20a and 20c is larger than the light intensity of the surface light sources 20b and 20d according to the amount of movement. A pupil intensity distribution 20 is obtained.

  When the diffractive optical element 2A is moved in the + Z direction from the reference state, a quadrupole pupil having a property that the light intensity of the surface light sources 20b and 20d is larger than the light intensity of the surface light sources 20a and 20c according to the amount of movement. An intensity distribution 20 is obtained. When the diffractive optical element 2A is moved in the −X direction from the reference state, a quadrupolar shape having a property that the light intensity of the surface light sources 20a and 20b is larger than the light intensity of the surface light sources 20c and 20d according to the amount of movement. A pupil intensity distribution 20 is obtained.

  When the diffractive optical element 2A is moved in the + X direction from the reference state, a quadrupole pupil having a property that the light intensity of the surface light sources 20c and 20d is larger than the light intensity of the surface light sources 20a and 20b according to the amount of movement. An intensity distribution 20 is obtained. When the diffractive optical element 2A is moved from the reference state in a direction that forms 45 degrees with the −X direction and the −Z direction, the light intensity of the surface light source 20a depends on the amount of the movement of the other surface light sources 20b, 20c, and 20d. A quadrupole pupil intensity distribution 20 having a property larger than the light intensity is obtained.

  When the diffractive optical element 2A is moved from the reference state in a direction that forms 45 degrees with the −X direction and the + Z direction, the light intensity of the surface light source 20b depends on the amount of movement, and the light of the other surface light sources 20a, 20c, and 20d. A quadrupole pupil intensity distribution 20 having a property larger than the intensity is obtained. When the diffractive optical element 2A is moved from the reference state in a direction that forms 45 degrees with the + X direction and the -Z direction, the light intensity of the surface light source 20c depends on the amount of movement, and the light of the other surface light sources 20a, 20b, and 20d. A quadrupole pupil intensity distribution 20 having a property larger than the intensity is obtained.

  When the diffractive optical element 2A is moved from the reference state in the direction of 45 degrees with the + X direction and the + Z direction, the light intensity of the surface light source 20d is changed to the light intensity of the other surface light sources 20a, 20b, 20c according to the amount of movement. A quadrupole pupil intensity distribution 20 having a larger characteristic is obtained. As described above, in the modification of FIG. 6, the diffractive optical element 2 </ b> A is moved by a required distance in the required direction along the XZ plane to thereby obtain the surface light sources 20 a to 20 a for each pole in the quadrupole pupil intensity distribution 20. The balance of light intensity between 20d can be adjusted stably.

  In the modification of FIG. 6, the light between the surface light sources 20a to 20d of each pole in the quadrupole pupil intensity distribution 20 is obtained by the diffractive optical element 2A provided with the two types of unit diffraction regions B and C. The balance of strength is adjusted. However, the present invention is not limited to this. For example, a diffractive optical element provided with four types of unit diffraction regions D, E, F, and G may be used as in the case of the modification of FIG. The balance of light intensity between 20a-20d can also be adjusted.

  In this four-type diffractive optical element, the unit diffraction regions D, E, F, and G have a function of forming the quadrupolar light beams 21a to 21d shown in FIG. . In the quadrupolar light beams 21a to 21d formed by the unit diffraction regions D, the light intensity of the light beam 21a and the light intensity of the other light beams 21b to 21d are determined according to the type D ± i (i = 0 to n). The difference is different. In the quadrupolar light beams 21a to 21d formed by the unit diffraction regions E, the light intensity of the light beam 21b and the light beams of the other light beams 21a, 21c, and 21d according to the type E ± i (i = 0 to n). The difference in intensity is different.

  In the quadrupolar light beams 21a to 21d formed by the unit diffraction regions F, the light intensity of the light beam 21c and the light beams of the other light beams 21a, 21b, and 21d according to the type F ± i (i = 0 to n). The difference in intensity is different. In the quadrupolar light beams 21a to 21d formed by the unit diffraction regions G, the light intensity of the light beam 21d and the light intensity of the other light beams 21a to 21c are determined according to the type G ± i (i = 0 to n). The difference is different. Although not shown, by arranging these unit diffraction regions D, E, F, and G according to a required distribution, between the surface light sources 20 a to 20 d of each pole in the quadrupole pupil intensity distribution 20. The balance of light intensity can be adjusted.

  Further, in the modification of FIG. 6, one type of unit diffraction region B forms one dipolar light beam 21a, 21b of the quadrupolar light beam 21 shown in FIG. The unit diffraction region C of this type forms the remaining dipolar light beams 21c and 21d in the far field region. In other words, in the modified example of FIG. 6, one type of unit diffraction region B forms a light beam having the same first outer shape as a part of the optical region to be formed in the far field region in the far field region. The other type of unit diffraction region C forms a light beam having the same second outer shape as the remainder of the light region in the far field region.

  However, the present invention is not limited to this, and the first type of unit diffraction region is formed in the far field region with a light beam having the same first outer shape as a part of the light region to be superimposed. The unit diffraction region of the type forms a light beam having the same second outer shape as another part of the optical region in the far-field region, and the light beam of the third outer shape has the same third type unit diffraction region as the rest of the light region. May be formed in the far field region. At this time, the light beam having the first outer shape and the light beam having the second outer shape may partially overlap in the far field region. In this case, the outer shape of the light beam formed in the far-field region by the first-type unit diffraction region and the second-type unit diffraction region should be superimposed on the far-field region by the diffractive optical element. This is different from the outer shape of the light region.

  In the above description, the operational effects of the present invention are described by taking, as an example, modified illumination in which a quadrupole pupil intensity distribution is formed on the illumination pupil, that is, quadrupole illumination. However, the present invention is not limited to quadrupole illumination. For example, annular illumination in which an annular pupil intensity distribution is formed, multipolar illumination in which a multipolar pupil intensity distribution other than quadrupole is formed, and the like. In contrast, it is apparent that the same effects can be obtained by applying the present invention.

  In the above description, a unit diffraction region having a diffractive optical surface is used as a unit region for forming a light beam having a predetermined light intensity distribution in the far field region based on the incident light beam. However, the present invention is not limited to the unit diffraction region, and the light beam conversion element of the present invention can be configured by a plurality of types of unit refraction regions having a refractive optical surface, for example.

  In the above-described embodiment, a variable pattern forming apparatus that forms a predetermined pattern based on predetermined electronic data can be used instead of a mask. By using such a variable pattern forming apparatus, the influence on the synchronization accuracy can be minimized even if the pattern surface is placed vertically. As the variable pattern forming apparatus, for example, a DMD (digital micromirror device) including a plurality of reflecting elements driven based on predetermined electronic data can be used. An exposure apparatus using DMD is disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-304135, International Patent Publication No. 2006/080285 pamphlet and US Patent Publication No. 2007/0296936 corresponding thereto. In addition to a non-light-emitting reflective spatial light modulator such as DMD, a transmissive spatial light modulator may be used, or a self-luminous image display element may be used. Note that a variable pattern forming apparatus may be used even when the pattern surface is placed horizontally. Here, the teachings of US Patent Publication No. 2007/0296936 are incorporated by reference.

  In the above-described embodiment, the micro fly's eye lens 4 is used as the optical integrator, but instead, an internal reflection type optical integrator (typically a rod type integrator) may be used. In this case, the condensing lens is disposed on the rear side of the zoom lens 3 so that the front focal position thereof coincides with the rear focal position of the zoom lens 3, and the incident end is located at or near the rear focal position of the condensing lens. Position the rod-type integrator so that is positioned. At this time, the exit end of the rod integrator is the position of the illumination field stop 6. When using a rod type integrator, a position optically conjugate with the position of the aperture stop AS of the projection optical system PL in the field stop imaging optical system 7 downstream of the rod type integrator can be called an illumination pupil plane. . In addition, since a virtual image of the secondary light source of the illumination pupil plane is formed at the position of the entrance surface of the rod integrator, this position and a position optically conjugate with this position are also called the illumination pupil plane. Can do. Here, the zoom lens 3, the above-described condenser lens, and the rod integrator can be regarded as a distribution forming optical system.

  The exposure apparatus of the above-described embodiment is manufactured by assembling various subsystems including the respective constituent elements recited in the claims of the present application so as to maintain predetermined mechanical accuracy, electrical accuracy, and optical accuracy. Is done. In order to ensure these various accuracies, before and after assembly, various optical systems are adjusted to achieve optical accuracy, various mechanical systems are adjusted to achieve mechanical accuracy, and various electrical systems are Adjustments are made to achieve electrical accuracy. The assembly process from the various subsystems to the exposure apparatus includes mechanical connection, electrical circuit wiring connection, pneumatic circuit piping connection and the like between the various subsystems. Needless to say, there is an assembly process for each subsystem before the assembly process from the various subsystems to the exposure apparatus. When the assembly process of the various subsystems to the exposure apparatus is completed, comprehensive adjustment is performed to ensure various accuracies as the entire exposure apparatus. The exposure apparatus is preferably manufactured in a clean room where the temperature, cleanliness, etc. are controlled.

  Next, a device manufacturing method using the exposure apparatus according to the above-described embodiment will be described. FIG. 7 is a flowchart showing a semiconductor device manufacturing process. As shown in FIG. 7, in the semiconductor device manufacturing process, a metal film is vapor-deposited on a wafer W to be a semiconductor device substrate (step S40), and a photoresist, which is a photosensitive material, is applied on the vapor-deposited metal film. (Step S42). Subsequently, using the exposure apparatus of the above-described embodiment, the pattern formed on the mask (reticle) M is transferred to each shot area on the wafer W (step S44: exposure process), and the transfer of the wafer W after the transfer is completed. Development, that is, development of the photoresist to which the pattern has been transferred is performed (step S46: development process). Thereafter, using the resist pattern generated on the surface of the wafer W in step S46 as a mask, processing such as etching is performed on the surface of the wafer W (step S48: processing step).

  Here, the resist pattern is a photoresist layer in which unevenness having a shape corresponding to the pattern transferred by the exposure apparatus of the above-described embodiment is generated, and the recess penetrates the photoresist layer. is there. In step S48, the surface of the wafer W is processed through this resist pattern. The processing performed in step S48 includes, for example, at least one of etching of the surface of the wafer W or film formation of a metal film or the like. In step S44, the exposure apparatus of the above-described embodiment performs pattern transfer using the wafer W coated with the photoresist as the photosensitive substrate, that is, the plate P.

  FIG. 8 is a flowchart showing a manufacturing process of a liquid crystal device such as a liquid crystal display element. As shown in FIG. 8, in the manufacturing process of the liquid crystal device, a pattern formation process (step S50), a color filter formation process (step S52), a cell assembly process (step S54), and a module assembly process (step S56) are sequentially performed.

  In the pattern forming process of step S50, a predetermined pattern such as a circuit pattern and an electrode pattern is formed on the glass substrate coated with a photoresist as the plate P using the exposure apparatus of the above-described embodiment. In this pattern formation process, an exposure process for transferring the pattern to the photoresist layer using the exposure apparatus of the above-described embodiment and development of the plate P to which the pattern is transferred, that is, development of the photoresist layer on the glass substrate are performed. And a developing step for generating a photoresist layer having a shape corresponding to the pattern, and a processing step for processing the surface of the glass substrate through the developed photoresist layer.

  In the color filter forming step of step S52, a large number of sets of three dots corresponding to R (Red), G (Green), and B (Blue) are arranged in a matrix or three R, G, and B A color filter is formed by arranging a plurality of stripe filter sets in the horizontal scanning direction.

  In the cell assembly process in step S54, a liquid crystal panel (liquid crystal cell) is assembled using the glass substrate on which the predetermined pattern is formed in step S50 and the color filter formed in step S52. Specifically, for example, a liquid crystal panel is formed by injecting liquid crystal between a glass substrate and a color filter. In the module assembling process in step S56, various components such as an electric circuit and a backlight for performing the display operation of the liquid crystal panel are attached to the liquid crystal panel assembled in step S54.

  In addition, the present invention is not limited to application to an exposure apparatus for manufacturing a semiconductor device, for example, an exposure apparatus for a display device such as a liquid crystal display element formed on a square glass plate or a plasma display, It can also be widely applied to an exposure apparatus for manufacturing various devices such as an image sensor (CCD or the like), a micromachine, a thin film magnetic head, and a DNA chip. Furthermore, the present invention can also be applied to an exposure process (exposure apparatus) when manufacturing a mask (photomask, reticle, etc.) on which mask patterns of various devices are formed using a photolithography process.

In the above-described embodiment, ArF excimer laser light (wavelength: 193 nm) or KrF excimer laser light (wavelength: 248 nm) is used as the exposure light. However, the present invention is not limited to this, and other appropriate laser light sources are used. For example, the present invention can also be applied to an F ₂ laser light source that supplies laser light having a wavelength of 157 nm.

  In the above-described embodiment, a so-called immersion method is applied in which the optical path between the projection optical system and the photosensitive substrate is filled with a medium (typically liquid) having a refractive index larger than 1.1. You may do it. In this case, as a technique for filling the liquid in the optical path between the projection optical system and the photosensitive substrate, a technique for locally filling the liquid as disclosed in International Publication No. WO 99/49504, A method of moving a stage holding a substrate to be exposed as disclosed in Japanese Patent Laid-Open No. 6-124873 in a liquid bath, or a predetermined depth on a stage as disclosed in Japanese Patent Laid-Open No. 10-303114. A method of forming a liquid tank and holding the substrate in the liquid tank can be employed. Here, the teachings of International Publication No. WO99 / 49504, JP-A-6-124873 and JP-A-10-303114 are incorporated by reference.

  In the above-described embodiment, a so-called polarization illumination method disclosed in US Publication Nos. 2006/0170901 and 2007/0146676 can also be applied. Here, the teachings of US Patent Publication No. 2006/0170901 and US Patent Publication No. 2007/0146676 are incorporated by reference.

  In the above-described embodiment, the present invention is applied to the illumination optical system that illuminates the mask (or wafer) in the exposure apparatus. However, the present invention is not limited to this, and an object other than the mask (or wafer) is used. The present invention can also be applied to a general illumination optical system that illuminates the irradiation surface.

It is a figure which shows schematically the structure of the exposure apparatus concerning embodiment of this invention. It is a figure which shows the quadrupole secondary light source formed in an illumination pupil. It is a figure which shows roughly the principal part structure of the diffractive optical element of this embodiment. It is a figure which shows the quadrupolar light beam formed in a far field area | region through each unit diffraction area | region of a diffractive optical element. It is a figure explaining the relative positional relationship of the incident light beam with respect to a diffractive optical element. It is a figure which shows roughly the principal part structure of the mixed type diffractive optical element concerning the modification of this embodiment. It is a flowchart which shows the manufacturing process of a semiconductor device. It is a flowchart which shows the manufacturing process of liquid crystal devices, such as a liquid crystal display element.

Explanation of symbols

1 Beam Transmitting System 2, 2A Diffractive Optical Element 3 Zoom Lens 4 Micro Fly Eye Lens (Optical Integrator)
5 Condenser optical system 6 Mask blind 7 Imaging optical system LS Light source M Mask MS Mask stage PL Projection optical system AS Aperture stop W Wafer WS Wafer stage DT Pupil distribution measurement unit CR Control unit

Claims (29)

A light beam conversion element that converts an incident light beam to form a light region having an outer shape different from the incident light beam in a far field region,
A plurality of first unit regions for forming a light beam having a first light intensity distribution in the far field region;
A plurality of second unit regions for forming a light beam having a second light intensity distribution different from the first light intensity distribution in the far field region;
At least one of the second unit regions is located between the plurality of first unit regions. 2. The light flux conversion element according to claim 1, wherein at least one of the first unit regions is located between the plurality of second unit regions. 3. The light beam conversion element according to claim 1, wherein the first and second unit regions form a light beam having the same outer shape as the light region in the far field region. The first and second unit regions include a first pair of light fluxes spaced in the first direction in the far field region and a second pair spaced in a second direction orthogonal to the first direction. 4. The light beam conversion element according to claim 3, wherein a quadrupole light beam having a light beam is formed. The light flux conversion element according to claim 4, wherein the first pair of light beams have the same intensity, and the second pair of light beams have the same intensity. The said 1st and 2nd unit area | region forms the quadrupole light beam from which the intensity | strength difference of the said 1st pair of light beams and the said 2nd pair of light beams differs mutually. Luminous flux conversion element. The light beam conversion element according to claim 6, wherein the first and second unit regions are arranged according to the intensity difference. A plurality of third unit regions for forming a light beam of a third light intensity distribution different from the first and second light intensity distributions in the far field region;
The light beam conversion element according to claim 7, wherein the first to third unit regions are arranged in an order in which the intensity difference changes monotonously. The plurality of first unit regions form a light beam having the same first outer shape as a part of the light region in the far field region, and the plurality of second unit regions are separated from another part of the light region. The light beam conversion element according to claim 1, wherein a light beam having the same second outer shape is formed in the far field region. The plurality of first unit regions form a first pair of light beams spaced in a first direction in the far field region, and the plurality of second unit regions are orthogonal to the first direction in the far field region. The light flux conversion element according to claim 9, wherein a second pair of light fluxes spaced apart in the second direction is formed. The plurality of first unit regions and the plurality of second unit regions correspond to an intensity difference between one and the other of the first pair of light beams and an intensity difference between one and the other of the second pair of light beams. The light beam conversion element according to claim 10, wherein the light flux conversion elements are arranged in a line. The plurality of first unit regions are arranged in an order in which the intensity difference between one and the other of the first pair of light beams monotonously changes, and the plurality of second unit regions are arranged with one of the second pair of light beams. The light beam conversion element according to claim 11, wherein the light flux conversion elements are arranged in an order in which an intensity difference with the other changes monotonously. 13. The light beam according to claim 9, further comprising a plurality of third unit regions that form a light beam having the same third outer shape as the remainder of the light region in the far field region. Conversion element. 14. The light beam conversion element according to claim 9, wherein the first outer shape light beam and the second outer shape light beam partially overlap each other in the far field region. 3. The light beam conversion element according to claim 1, wherein the first and second unit regions form a light beam having an outer shape different from that of the light region in the far field region. A light beam conversion element that converts an incident light beam to form a light region having an outer shape different from the incident light beam in a far field region,
A plurality of types of unit regions for forming light beams with different light intensity distributions in the far field region based on each incident light beam,
The plurality of types of unit regions are arranged such that the light intensity distribution of the light region changes without changing the outer shape of the light region according to a change in the position of the incident light beam with respect to the light beam conversion element. A light beam conversion element characterized by comprising: The light beam conversion element according to any one of claims 1 to 16, wherein the unit region is formed on a surface of the light beam conversion element. The light beam conversion element according to claim 1, wherein the unit region has a diffractive optical surface. The light beam conversion element according to claim 1, wherein the unit region has a refractive optical surface. In the illumination optical system that illuminates the illuminated surface with light from the light source,
The light beam conversion element according to any one of claims 1 to 19,
An illumination optical system comprising: a distribution forming optical system that forms a predetermined light intensity distribution in an illumination pupil of the illumination optical system based on light that has passed through the light beam conversion element. The illumination optical system according to claim 20, wherein the distribution forming optical system includes an optical integrator and a condensing optical system disposed in an optical path between the optical integrator and the light beam conversion element. . The projection pupil is used in combination with a projection optical system that forms a surface optically conjugate with the irradiated surface, and the illumination pupil is at a position optically conjugate with an aperture stop of the projection optical system. The illumination optical system according to 20 or 21. A pupil distribution measurement unit that measures a light intensity distribution formed in the illumination pupil on the illumination pupil or a surface optically conjugate with the illumination pupil, and the light flux conversion element based on a measurement result by the pupil distribution measurement unit; 23. The illumination optical system according to claim 20, further comprising a control unit that controls a relative position with respect to the incident light beam. 24. The illumination optical system according to claim 23, wherein the control unit moves the light beam conversion element in a direction crossing an optical axis of the illumination optical system. The illumination optical system according to claim 23 or 24, wherein the control unit moves a position of the incident light beam incident on the light beam conversion element. 26. An exposure apparatus comprising the illumination optical system according to any one of claims 20 to 25 for illuminating a predetermined pattern, and exposing the predetermined pattern onto a photosensitive substrate. 27. The exposure apparatus according to claim 26, further comprising a projection optical system that forms an image of the predetermined pattern on the photosensitive substrate. The pupil distribution measurement unit measures a pupil intensity distribution on a pupil plane of the projection optical system based on light via the projection optical system,
The said control part controls the position of the said incident light beam with respect to the said light beam conversion element based on the measurement result of the said pupil distribution measurement part, in order to adjust the said pupil intensity distribution to required distribution. 27. The exposure apparatus according to 27. An exposure step of exposing the predetermined pattern to the photosensitive substrate using the exposure apparatus according to any one of claims 26 to 28;
Developing the photosensitive substrate to which the predetermined pattern is transferred, and forming a mask layer having a shape corresponding to the predetermined pattern on the surface of the photosensitive substrate;
And a processing step of processing the surface of the photosensitive substrate through the mask layer.

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