JP2010153663A - Lighting optical system, exposure system and method of manufacturing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting optical system and exposure system that adjust light intensity distribution on a surface to be irradiated, and a method of manufacturing a device. <P>SOLUTION: The lighting optical system includes: a first optical integrator 26 having a plurality of cylindrical lens surfaces 54 arranged inside the surfaces intersecting with optical axes of the lighting optical system and forming predetermined light intensity distribution on a lighting pupil surface when exposure light (EL) is incident from a light source; a second optical integrator 65, being arranged on the light source side of the first optical integrator 26, with a plurality of cylindrical lens surfaces 66 corresponding to each of the plurality of cylindrical lens surfaces 54; and a movement mechanism for moving the second optical integrator 65 along a Y axis direction so that a spacing between the first and second integrator 26 and 65 is changed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an illumination optical system that illuminates a surface to be irradiated based on light emitted from a light source, an exposure apparatus that includes the illumination optical system, and a device manufacturing method that uses the exposure apparatus.

  In general, an exposure apparatus for manufacturing a microdevice such as a semiconductor integrated circuit includes an illumination optical system for guiding exposure light output from a light source to a mask such as a reticle on which a predetermined pattern is formed. Such an illumination optical system is provided with a fly-eye lens as an optical integrator. When exposure light is incident on the fly-eye lens, the illumination pupil at a position optically Fourier-transformed with respect to the irradiated surface of the mask on the exit surface side of the fly-eye lens is composed of a number of light sources. A secondary light source is formed as a substantial surface light source. The secondary light source indicates a light intensity distribution at the illumination pupil (hereinafter referred to as “pupil intensity distribution”).

  The exposure light from such a secondary light source is condensed by a condenser lens and then illuminates the mask in a superimposed manner. The exposure light transmitted through the mask is irradiated onto a substrate such as a wafer to which a photosensitive material is applied via a projection optical system. As a result, the mask pattern is projected and transferred (transferred) onto the substrate.

By the way, in recent years, higher integration (miniaturization) of patterns formed on a mask has been advanced. Therefore, in order to accurately transfer the fine pattern of the mask onto the substrate, it is essential to form an irradiation region having a uniform illuminance distribution on the substrate. Therefore, conventionally, in order to accurately transfer the fine pattern of the mask onto the substrate, for example, an annular or multipolar (bipolar, quadrupolar, etc.) pupil intensity distribution is formed, and the focus of the projection optical system A technique for improving depth and resolving power has been proposed (see Patent Document 1).
US Patent Publication No. 2006/0055834

  By the way, when the fine pattern of the mask is accurately transferred onto the substrate, not only the pupil intensity distribution is adjusted to a desired shape, but also the light intensity at each point on the substrate, which is the final irradiated surface, is approximately It is necessary to adjust uniformly. If there is variation in the light intensity at each point on the substrate, the line width of the pattern varies from position to position on the substrate, and the fine pattern of the mask is accurately applied to the substrate with the desired line width over the entire exposure area. There was a possibility that it could not be transferred.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an illumination optical system, an exposure apparatus, and a device manufacturing method capable of adjusting a light intensity distribution on an irradiated surface. There is.

In order to solve the above-described problems, the present invention employs the following configuration corresponding to FIGS. 1 to 18 shown in the embodiment.
The illumination optical system of the present invention is an illumination optical system (13) that illuminates the irradiated surface (Ra, Wa) with light (EL) from a light source (12), and the optical axis of the illumination optical system (13). A plurality of first unit wavefront division planes (50a, 50b) arranged in planes (50a, 50b) intersecting (AX), and light (EL) from the light source (12) is incident The first optical integrator (26) that forms a predetermined light intensity distribution on the illumination pupil plane (50a, 50b) in the illumination optical path of the illumination optical system (13), and the first optical integrator (26) of the first optical integrator (26). A second optical integrator (65, 50) arranged on the light source (12) side and having a plurality of second unit wavefront dividing surfaces (50a, 50b) individually corresponding to the plurality of first unit wavefront dividing surfaces (50a, 50b). 65A) and the above And the light of the illumination optical system (13) to change at least one of the second optical integrator (65, 65A) and the distance between the first and second optical integrators (26, 65, 65A). And a moving mechanism (73, 74, 75, 76) that moves along the axial direction.

  According to the said structure, by changing the space | interval between 1st and 2nd optical integrators (26, 65, 65A), each 1st unit wave-front division | segmentation surface (50a, 50a of a 1st optical integrator (26)) is changed. 50b), the light intensity at each position is adjusted. As a result, the light intensity distribution (also referred to as “pupil intensity distribution”) at each point on the irradiated surface (Ra, Wa) is independently adjusted. Therefore, it is possible to adjust the light intensity distribution at each point on the irradiated surface (Ra, Wa) to a distribution having substantially the same property.

  In order to explain the present invention in an easy-to-understand manner, it has been described in association with the reference numerals of the drawings showing the embodiments, but it goes without saying that the present invention is not limited to the embodiments.

  According to the present invention, the light intensity distribution on the irradiated surface can be adjusted.

(First embodiment)
Below, 1st Embodiment which actualized this invention is described based on FIGS. In the present embodiment, the optical axis (vertical direction in FIG. 1) of the projection optical system 15 to be described later is referred to as the Z-axis direction, the horizontal direction in FIG. 1 is referred to as the Y-axis direction, and in FIG. The direction to do is referred to as the X-axis direction.

  As shown in FIG. 1, the exposure apparatus 11 of the present embodiment illuminates exposure light EL onto a transmissive reticle R on which a predetermined circuit pattern is formed, thereby providing a surface Wa (+ Z direction side surface). 1 is an apparatus for projecting an image of a circuit pattern onto a wafer W coated with a photosensitive material such as a resist on the upper surface in FIG. Such an exposure apparatus 11 includes an illumination optical system 13 that guides the exposure light EL emitted from the light source device 12 to an irradiated surface Ra (surface on the + Z direction side) of the reticle R, a reticle stage 14 that holds the reticle R, and a reticle. A projection optical system 15 that guides the exposure light EL that has passed through R to the surface Wa of the wafer W, and a wafer stage 16 that holds the wafer W are provided. Note that the light source device 12 of this embodiment has an ArF excimer laser light source that outputs light having a wavelength of 193 nm, and light output from the ArF excimer laser light source is guided into the exposure device 11 as exposure light EL.

  The illumination optical system 13 includes a shaping optical system 17 for converting the exposure light EL emitted from the light source device 12 into a parallel light beam having a predetermined cross-sectional shape (for example, a substantially rectangular cross section), and the shaping optical system 17. And a first reflection mirror 18 that reflects the exposure light EL emitted from the light to the reticle R side (here, the + Y direction side and the right side in FIG. 1). A diffractive optical element 19 is provided on the exit side (reticle R side) of the first reflecting mirror 18. The diffractive optical element 19 is formed by forming a plurality of steps having a pitch approximately equal to the wavelength of the exposure light EL on the glass substrate. The diffractive optical element 19 receives the exposure light EL incident from the incident side (light source device 12 side). It has the effect of diffracting to a predetermined angle. For example, when the diffractive optical element 19 for annular illumination is used, when the exposure light EL of a parallel light beam having a substantially rectangular cross section is incident on the diffractive optical element 19 from the incident side, the cross-sectional shape is changed from the diffractive optical element 19. A luminous flux having an annular shape (substantially annular shape) is emitted to the reticle R side. Further, when the diffractive optical element 19 for illuminating a plurality of poles (two poles, four poles, eight poles, etc.) is used, exposure light EL of a parallel light beam having a substantially rectangular cross section enters the diffractive optical element 19 from the incident side. From the diffractive optical element 19, a plurality of (for example, four) light beams corresponding to the number of poles are emitted to the reticle R side.

  In addition, the illumination optical system 13 is provided with an afocal optical system 20 (also referred to as “non-focal optical system”) on which the exposure light EL emitted from the diffractive optical element 19 enters. The afocal optical system 20 includes a first lens group 21 (only one lens is shown in FIG. 1) and a second lens group 22 (shown in FIG. 1) arranged on the exit side from the first lens group 21. Only one lens is shown). The focal position on the incident side of the afocal optical system 20 is substantially the same as the installation position of the diffractive optical element 19, and the focal position on the exit side of the afocal optical system 20 is a predetermined surface indicated by a broken line in FIG. It is formed so as to be substantially the same as the position 23.

  Further, in the optical path between the first lens group 21 and the second lens group 22, the exposure light EL is located at a position optically conjugate with or near the illumination pupil plane 27 of the first optical integrator 26 described later. A correction filter 24 having a transmittance distribution with different transmittances according to the incident position is provided. The correction filter 24 is a filter in which a light-shielding dot pattern made of chromium, chromium oxide, or the like is formed on a glass substrate whose incident side surface and emission side surface are parallel.

  Further, on the reticle R side of the afocal optical system 20, a zoom for varying the σ value (σ value = the numerical aperture on the reticle R side of the illumination optical system 13 / the numerical aperture on the reticle R side of the projection optical system 15). An optical system 25 is provided, and the zoom optical system 25 is disposed on the exit side with respect to the predetermined surface 23. Further, on the exit side of the zoom optical system 25, a first optical integrator 26 and a distribution correction optical system 31 for adjusting the amount of exposure light EL incident on the first optical integrator 26 are provided. The distribution correction optical system 31 includes an illumination area ER1 (see FIG. 4A) formed on the reticle R and a static exposure area formed on the wafer W that is optically conjugate with the illumination area ER1. It is an optical system for correcting the light intensity distribution at each point in ER2 (see FIG. 4B). A specific configuration of the distribution correction optical system 31 will be described later.

  In the first optical integrator 26, the incident surface (the surface on the −Y direction side and the left surface in FIG. 1) has a focal position (also referred to as a pupil plane) on the exit side of the zoom optical system 25 or in the vicinity of the focal position. It is arranged to be located in. That is, the incident surface of the first optical integrator 26 is substantially in a Fourier transform relationship with the predetermined surface 23, and the incident surface of the first optical integrator 26 is the pupil plane of the afocal optical system 20 (that is, The position of the correction filter 24 is optically substantially conjugate with the positional relationship). The exposure light EL is incident on the first optical integrator 26 in a state of being converted into a parallel light beam from the zoom optical system 25 side. Then, the first optical integrator 26 wave-divides the incident exposure light EL into a plurality of light fluxes, and generates a predetermined light intensity distribution (“pupil intensity distribution” on the illumination pupil plane 27 located on the exit side (+ Y direction side). Is also formed.). The illumination pupil plane 27 on which the pupil intensity distribution is formed is also referred to as a secondary light source 60 (see FIG. 3) composed of a number of surface light sources.

  On the exit side of the first optical integrator 26, it is arranged at a position optically conjugate with the entrance pupil plane of the projection optical system 15, and is not shown for defining a range that contributes to illumination of the secondary light source 60. An illumination aperture stop is provided. This illumination aperture stop has a plurality of openings having different sizes and shapes. In the illumination aperture stop, an opening corresponding to the cross-sectional shape of the exposure light EL emitted from the secondary light source 60 is disposed in the optical path of the exposure light EL. That is, when the cross-sectional shape of the exposure light EL emitted from the secondary light source 60 is an annular shape, the illumination aperture stop is driven so that the opening corresponding to the annular shape is located in the optical path of the exposure light EL. It is supposed to be. In addition, when the cross-sectional shape of the exposure light EL emitted from the secondary light source 60 is quadrupole, the illumination aperture stop has an opening having a shape corresponding to the quadrupole shape in the optical path of the exposure light EL. To drive.

  On the exit side of the first optical integrator 26 and the illumination aperture stop, a first condenser optical system 28 including at least one lens (only one is shown in FIG. 1), and the first condenser optical system 28 And a reticle blind 29 (also referred to as a “mask blind”) disposed at a position optically conjugate with the irradiated surface Ra of the reticle R. The first condenser optical system 28 includes an optical element (lens) having power (reciprocal of focal length). The reticle blind 29 is formed with a rectangular opening 29a whose longitudinal direction is the Z-axis direction and whose lateral direction is the X-axis direction. The exposure light EL emitted from the first condenser optical system 28 illuminates the reticle blind 29 in a superimposed manner. The optical element having power is an optical element in which the characteristics of the exposure light EL change when the exposure light EL enters the optical element.

  Further, a second condenser optical system 30 composed of a lens having power is provided on the exit side of the reticle blind 29, and the second condenser optical system 30 substantially receives light incident from the reticle blind 29 side. The light is converted into a parallel light beam. An imaging optical system 32 is provided on the exit side of the second condenser optical system 30. The imaging optical system 32 includes an incident side lens group 33, a second reflecting mirror 34 that reflects the exposure light EL emitted from the incident side lens group 33 to the −Z direction side (lower side in FIG. 1), And an exit side lens group 35 disposed on the exit side of the second reflecting mirror 34. The incident side lens group 33 is composed of at least one optical element (lens) having power (only one is shown in FIG. 1), and the emission side lens group 35 is at least one (one in FIG. 1). It is comprised from the optical element (lens) which has the power of only illustration. The exposure light EL emitted from the imaging optical system 32 illuminates the irradiated surface Ra of the reticle R in a superimposed manner. In the present embodiment, the shape of the opening 29a of the reticle blind 29 is rectangular as described above. Therefore, as shown in FIGS. 4A and 4B, the illumination area ER1 on the reticle R and the static exposure area ER2 on the wafer W are in the Y-axis direction as the first direction and short. Each is formed in a rectangular shape whose direction is the X-axis direction as the second direction.

  As shown in FIG. 1, the reticle stage 14 is arranged on the object plane side of the projection optical system 15 so that the mounting surface of the reticle R is substantially orthogonal to the optical axis direction (Z-axis direction) of the projection optical system 15. Has been. The reticle stage 14 is provided with a reticle stage drive unit (not shown) that moves the held reticle R with a predetermined stroke in the X-axis direction.

  A pupil intensity distribution measuring device 36 is provided in the vicinity of the reticle stage 14. The pupil intensity distribution measuring device 36 is a device that measures the pupil intensity distribution formed by each incident light incident on one point in the illumination area ER1 on the reticle R in the secondary light source 60 for each point (for each position). . The pupil intensity distribution measuring device 36 includes a beam splitter 37 that reflects part of the exposure light EL (also referred to as “reflected light”) emitted from the exit side lens group 35 toward the reticle R, and the beam splitter 37. A measurement lens 38 on which the reflected light reflected by the laser beam enters, and a detection unit 39 on which the reflected light emitted from the measurement lens 38 enters. The detection unit 39 includes a CCD imaging device, a photodiode, and the like, and a detection signal corresponding to the incident reflected light is output from the detection unit 39 to the control device 40. And the control apparatus 40 derives | leads-out the pupil intensity distribution for every point of the illumination area ER1 based on the detection signal from the detection part 39. FIG. The pupil intensity distribution measuring device 36 is disclosed in, for example, Japanese Patent Application Laid-Open No. 2006-54328, Japanese Patent Application Laid-Open No. 2003-22967, and US Patent Publication No. 2003/0038225 corresponding thereto.

  The projection optical system 15 includes a lens barrel 41 filled with an inert gas such as nitrogen, and a plurality of lenses (not shown) are provided in the lens barrel 41 along the optical path (Z-axis direction) of the exposure light EL. Is provided. In addition, an aperture stop 42 is disposed in the lens barrel 41 at a position that is optically Fourier-transformed with the installation position of the surface Wa of the wafer W and the installation position of the irradiated surface Ra of the reticle R. Then, the image of the circuit pattern on the reticle R illuminated with the exposure light EL is projected and transferred onto the wafer W on the wafer stage 16 in a state reduced to a predetermined reduction magnification via the projection optical system 15. . Here, the optical path indicates a path through which the exposure light EL is intended to pass in the use state.

  The wafer stage 16 includes a planar placement surface 43 that is substantially orthogonal to the optical axis of the projection optical system 15, and the wafer W is placed on the placement surface 43. The wafer stage 16 is provided with a wafer stage driving unit (not shown) that moves the wafer W to be held in the X-axis direction with a predetermined stroke. Further, the wafer stage 16 is provided with a function of finely adjusting the position of the wafer W so that the surface Wa of the wafer W is perpendicular to the optical axis of the projection optical system 15.

  When a pattern image is projected onto the wafer W using the exposure apparatus 11 of the present embodiment, the reticle R is driven from the + X direction side to the −X direction side (in FIG. From the side to the back side of the drawing) at every predetermined stroke. Then, the illumination area ER1 in the reticle R moves from the −X direction side of the irradiated surface Ra of the reticle R along the + X direction side (in FIG. 1, from the back side to the front side of the paper). That is, the pattern of the reticle R is sequentially scanned from the −X direction side to the + X direction side. Further, the wafer W is driven from the −X direction side to the + X direction side at a speed ratio corresponding to the reduction magnification of the projection optical system 15 with respect to the movement of the reticle R along the X-axis direction by driving the wafer stage driving unit. Move synchronously. As a result, a pattern having a shape obtained by reducing the circuit pattern on the reticle R to a predetermined reduction ratio is formed in one shot region of the wafer W in accordance with the synchronous movement of the reticle R and the wafer W. When the pattern formation on one shot area is completed, the pattern formation on the other shot areas of the wafer W is continuously performed.

  Next, the first optical integrator 26 of the present embodiment will be described with reference to FIG. In FIG. 2, it is assumed that the sizes of the cylindrical lens surfaces 52, 53, 54, and 55, which will be described later, are exaggerated for convenience of understanding the description.

  As shown in FIG. 2, the first optical integrator 26 includes a pair of micro fly's eye lenses 50 disposed along the optical axis AX of the illumination optical system 13 (indicated by a one-dot chain line in FIGS. 1 and 2). 51 is provided. These micro fly's eye lenses 50 and 51 are respectively formed such that the illumination pupil plane 27 located on the exit side of the first optical integrator 26 is formed at a position optically conjugate with the aperture stop 42 of the projection optical system 15. Has been placed.

  On the incident side of the first micro fly's eye lens 50 positioned on the incident side and on the incident side of the second micro fly's eye lens 51 positioned on the exit side, an incident surface 50a that is substantially orthogonal to the optical axis AX of the illumination optical system 13. , 51a are formed. Further, on the exit side of the first micro fly's eye lens 50 and the exit side of the second micro fly's eye lens 51, exit surfaces 50b and 51b that are substantially orthogonal to the optical axis AX of the illumination optical system 13 are formed, respectively. . A plurality (10 in FIG. 2) of cylindrical lens surfaces 52 and 53 extending in the Z-axis direction are arranged along the X-axis direction on the incident surfaces 50a and 51a side of both the micro fly's eye lenses 50 and 51, respectively. ing. Each of the cylindrical lens surfaces 52 and 53 is formed so as to have a shape obtained by cutting a part of a cylinder, and the length (that is, the width) of each cylindrical lens surface 52 and 53 in the X-axis direction is the first. One width H1.

  In addition, a plurality (10 in FIG. 2) of cylindrical lens surfaces 54 and 55 extending in the X-axis direction are arranged along the Z-axis direction on the exit surfaces 50b and 51b side of both the micro fly's eye lenses 50 and 51, respectively. ing. Each of the cylindrical lens surfaces 54 and 55 is formed to have a shape obtained by cutting a part of a cylinder, and the length (that is, the width) of each cylindrical lens surface 54 and 55 in the Z-axis direction is the first. The second width H2 is wider than the first width H1. The first width H1 and the second width H2 are the length in the X-axis direction and the length in the Z-axis direction of the opening 29a of the reticle blind 29, that is, the length in the X-axis direction of the illumination area ER1 and the still exposure area ER2. And the length in the Y-axis direction correspond to each other.

  When attention is paid to the refraction action in the X-axis direction of the first optical integrator 26, the exposure light EL incident along the optical axis AX of the illumination optical system 13 is formed on the incident surface 50a of the first micro fly's eye lens 50. Each of the cylindrical lens surfaces 52 is divided into wavefronts along the X-axis direction at intervals of the first width H1. The light beams divided by the respective cylindrical lens surfaces 52 are focused on the corresponding cylindrical lens surfaces among the respective cylindrical lens surfaces 53 formed on the incident surface 51a of the second micro fly's eye lens 51. Then, the light is condensed on the illumination pupil plane 27 located on the exit side of the first optical integrator 26. When attention is paid to the refraction action in the Z-axis direction of the first optical integrator 26, the exposure light EL incident along the optical axis AX of the illumination optical system 13 is incident on the exit surface 50b of the first micro fly's eye lens 50. Each of the formed cylindrical lens surfaces 54 is divided into wavefronts at intervals of the second width H2 along the X-axis direction. The light beams divided by the respective cylindrical lens surfaces 54 are condensed on the corresponding cylindrical lens surfaces among the respective cylindrical lens surfaces 55 formed on the exit surface 51b of the second micro fly's eye lens 51. Then, the light is condensed on the illumination pupil plane 27 located on the exit side of the first optical integrator 26.

  That is, in the present embodiment, the exposure light EL that has entered the first optical integrator 26 is wavefront divided along the X-axis direction by the respective cylindrical lens surfaces 52 that are located on the incident side, and then each of the exposure light EL that is located on the emission side. The wavefront is divided along the Z-axis direction by the cylindrical lens surface 54. As a result, a large number of point light sources 77 to 79 (see FIGS. 13 to 15) are formed on the illumination pupil plane 27.

  Note that the first width H1 and the second width H2 of the cylindrical lens surfaces 52 to 55 of the micro fly's eye lenses 50 and 51 are originally very narrow. For this reason, the number of wavefront divisions in the first optical integrator 26 of the present embodiment is greater than when a fly-eye lens composed of a plurality of lens elements is used. As a result, the global light intensity distribution formed on the incident side of the first optical integrator 26 and the global light intensity distribution of the entire secondary light source formed on the illumination pupil plane 27 on the exit side are: High correlation with each other. Therefore, the light intensity distribution on the incident side of the first optical integrator 26 and on a plane optically conjugate with the incident side can also be referred to as a pupil intensity distribution.

  Here, when a diffractive optical element for annular illumination is used as the diffractive optical element 19, an annular illumination field around the optical axis AX of the illumination optical system 13 is provided on the incident side of the first optical integrator 26. Is formed. As a result, an annular secondary light source 60 is formed on the illumination pupil plane 27 located on the exit side of the first optical integrator 26, the same as the annular illumination field formed on the incident side. When a diffractive optical element for multipole illumination is used as the diffractive optical element 19, a plurality of predetermined shapes (circles) around the optical axis AX of the illumination optical system 13 are formed on the incident side of the first optical integrator 26. A multipolar illuminating field consisting of arcuate and circular illuminating fields is formed. As a result, a multi-polar secondary light source 60 is formed on the illumination pupil plane 27 located on the exit side of the first optical integrator 26, the same as the multi-polar illumination field formed on the incident side. In the present embodiment, a diffractive optical element 19 for quadrupole illumination is used.

  That is, on the illumination pupil plane 27 located on the exit side of the first optical integrator 26, as shown in FIG. 3, four arc-shaped substantial surface light sources (hereinafter simply referred to as “surface light sources”) 60a. , 60b, 60c, 60d, a quadrupolar secondary light source 60 (pupil intensity distribution) is formed. Specifically, the secondary light source 60 includes an arc-shaped first surface light source 60a positioned on the + X direction side of the optical axis AX of the illumination optical system 13, and a −X direction side of the optical axis AX of the illumination optical system 13. A second arc surface-shaped second surface light source 60b is provided, and the distance between the first surface light source 60a and the optical axis AX is substantially equal to the distance between the second surface light source 60b and the optical axis AX. Yes. The secondary light source 60 includes an arcuate third surface light source 60c positioned on the + Z direction side of the optical axis AX of the illumination optical system 13, and a circle positioned on the −Z direction side of the optical axis AX of the illumination optical system 13. An arcuate fourth surface light source 60d is provided, and the distance between the third surface light source 60c and the optical axis AX is substantially equal to the distance between the fourth surface light source 60d and the optical axis AX. Each of the surface light sources 60a to 60d includes a plurality of point light sources 77 to 79 (see FIGS. 13 to 15) formed on the illumination pupil plane 27 by the first optical integrator 26.

  When each exposure light EL emitted from each of the surface light sources 60a to 60d is guided onto the reticle R, as shown in FIG. 4A, the longitudinal direction is on the Y axis on the irradiated surface Ra of the reticle R. A rectangular illumination region ER1 that is a direction and whose short direction is the X-axis direction is formed. Further, as shown in FIG. 4B, a rectangular still exposure region ER2 corresponding to the illumination region ER1 on the reticle R is formed on the surface Wa of the wafer W. At this time, each of the quadrupole pupil intensity distributions formed by the incident light incident on each point in the still exposure region ER2 (and the illumination region ER1) does not depend on the position where the exposure light EL is incident on each other. It has almost the same shape. However, the light intensity of the quadrupole pupil intensity distribution for each point in the still exposure region ER2 (and the illumination region ER1) tends to vary depending on the position of the exposure light EL incident on the still exposure region ER2. There is.

  Specifically, as shown in FIG. 5, exposure light EL (also referred to as “first incident light”) incident on center points P1a and P1b in the Y-axis direction in the illumination region ER1 and the static exposure region ER2. In the formed first pupil intensity distribution 61, the light intensity of the third surface light source 61c and the fourth surface light source 61d arranged along the Z-axis direction is the first surface arranged along the X-axis direction. There is a tendency to be stronger than the light intensity of the light source 61a and the second surface light source 61b. Most of each first incident light forming each surface light source 61a to 61d is a central portion in the X-axis direction of each cylindrical lens surface 52 of the first micro fly's eye lens 50 and the Z-axis direction of each cylindrical lens surface 54. Is the exposure light EL that passes through the central portion. Each such first incident light is emitted from each of the surface light sources 61a to 61d along the optical axis AX of the illumination optical system 13.

  On the other hand, as shown in FIGS. 4 (a), 4 (b) and 6, each peripheral point P2a, P3a, separated along the Y-axis direction of the center points P1a, P1b in the illumination region ER1 and the still exposure region ER2. Each exposure light EL incident on P2b and P3b (hereinafter, light incident on the peripheral point P2b is also referred to as “second incident light” and light incident on the peripheral point P3b is also referred to as “third incident light”). In the second pupil intensity distribution 62, the light intensity of the third surface light source 62c and the fourth surface light source 62d arranged along the Z-axis direction is the first surface light source arranged along the X-axis direction. There exists a tendency for it to become weaker than the light intensity of 62a and the 2nd surface light source 62b. Most of the second incident light and the third incident light forming the surface light sources 62a to 62d are both end portions in the X-axis direction of the cylindrical lens surfaces 52 of the first micro fly's eye lens 50, and the cylindrical lens surfaces. 54 is exposure light EL that passes through both end portions in the Z-axis direction. The second incident light and the third incident light are emitted from the surface light sources 62a to 62d in a state having a predetermined angle with respect to the optical axis AX of the illumination optical system 13. It should be noted that the pupil intensity distributions 61 and 62 referred to here are the illumination pupil plane 27 and the illumination pupil plane 27 and optical when the correction filter 24 is not disposed in the optical path of the exposure light EL in the illumination optical system 13. The light intensity distributions corresponding to the points P1b, P2b, and P3b in the static exposure region ER2 formed on the conjugated pupil conjugate plane are shown.

  In general, the light intensity distribution along the Z-axis direction of the first pupil intensity distribution 61 corresponding to the center points P1a and P1b has the weakest center in the Z-axis direction as shown in FIG. The distribution is a concave curve that gradually becomes stronger as the distance from the first Z-axis increases along the Z-axis direction. Further, the light intensity distribution along the Z-axis direction of each second pupil intensity distribution 62 corresponding to each peripheral point P2a, P2b, P3a, P3b has a center in the Z-axis direction as shown in FIG. The distribution is a convex curved surface that becomes the strongest and gradually weakens as the distance from the center along the Z-axis direction increases.

  The light intensity distribution along the Z-axis direction of the pupil intensity distributions 61 and 62 hardly depends on the position of each point along the X-axis direction in the illumination region ER1 and the still exposure region ER2, but the illumination region ER1 and There is a tendency to change depending on the position of each point along the Y-axis direction in the still exposure region ER2. Therefore, when the pupil intensity distributions 61 and 62 individually corresponding to the points P1b, P2b, and P3b along the Y-axis direction in the still exposure region ER2 are not uniform, the line width of the pattern formed on the wafer W is set. Variations may occur. In order to solve such a problem, a correction filter 24 and a distribution correction optical system 31 are provided in the illumination optical system 13 of the present embodiment.

  In addition, the correction filter 24 of this embodiment dimmes the light flux that constitutes the third surface light source 60c and the fourth surface light source 60d along the Z-axis direction among the secondary light sources 60 formed on the illumination pupil plane 27. On the other hand, it has a transmittance distribution that hardly diminishes the light beams constituting the first surface light source 60a and the second surface light source 60b along the X-axis direction.

Next, the distribution correction optical system 31 of this embodiment will be described with reference to FIGS.
As shown in FIGS. 8 and 9, the distribution correction optical system 31 includes a second optical integrator 65. An incident surface 65a substantially orthogonal to the optical axis AX of the illumination optical system 13 is formed on the incident side of the second optical integrator 65, and the optical axis AX is disposed on the emission side of the second optical integrator 65. A substantially orthogonal exit surface 65b is formed. A plurality (seven in FIG. 2) of cylindrical lens surfaces 66 and 67 extending in the X-axis direction are arranged on both surfaces 65a and 65b of the second optical integrator 65, respectively, along the X-axis direction. Each of the cylindrical lens surfaces 66 and 67 is formed to have a shape obtained by cutting a part of a cylinder, and the length (that is, the width) of each cylindrical lens surface 66 and 67 in the Z-axis direction is the first. This is substantially the same as the width (second width H2) of the cylindrical lens surfaces 54 and 55 of the first optical integrator 26.

  Then, when the exposure light EL (that is, a parallel light beam) is incident on the second optical integrator 65 from the zoom optical system 25, the exposure light EL is moved in the Z-axis direction by each cylindrical lens surface 66 formed on the incident surface 65a. A wavefront is divided along the second width H2. The light beams divided by the cylindrical lens surfaces 66 are subjected to a condensing action on the corresponding cylindrical lens surfaces of the cylindrical lens surfaces 67 formed on the exit surface 65b. Thereafter, each light beam emitted from each cylindrical lens surface 67 is incident on the first optical integrator 26 (that is, the first micro fly's eye lens 50).

  The second optical integrator 65 includes a plurality of (four in this embodiment) split integrators 68, 69, 70, 71 having a plurality of unit wavefront split planes. Each of these split integrators 68 to 71 is disposed so as to be adjacent to each other along the circumferential direction around the optical axis AX of the illumination optical system 13. The exposure light EL that forms the first surface light source 60a on the illumination pupil plane 27 is incident on the first split integrator 68 located on the + X direction side among the split integrators 68 to 71, and on the −X direction side. The exposure light EL that forms the second surface light source 60b on the illumination pupil plane 27 is incident on the second split integrator 69 that is positioned. The third split integrator 70 located on the + Z direction side is exposed to the exposure light EL that forms the third surface light source 60c on the illumination pupil plane 27, and the fourth split integrator 71 located on the −Z direction side. In the illumination pupil plane 27, the exposure light EL that forms the fourth surface light source 60d is incident. In this way, incident areas 72a, 72b, 72c, and 72d (areas surrounded by broken lines in FIG. 8) each having a substantially arc shape are formed on the incident side of each of the split integrators 68 to 71 on which the exposure light EL is incident. Is done.

  Further, the distribution correction optical system 31 is provided with moving mechanisms 73, 74, 75, and 76 for individually moving the divided integrators 68 to 71 along the Y-axis direction. Each of the moving mechanisms 73 to 76 has a guide portion (not shown) extending along the Y-axis direction and drive sources 73a, 74a, 75a, and 76a that are driven based on a control command from the control device 40, respectively. And each moving mechanism 73-76 moves each division | segmentation integrator 68-71 respectively along the direction (Y-axis direction) where a guide part is extended based on the drive of the drive sources 73a-76a.

  Next, the position of the second optical integrator 65 with respect to the first optical integrator 26 (first micro fly's eye lens 50), and the light of the exposure light EL incident on each cylindrical lens surface 54 of the first micro fly's eye lens 50. The relationship with strength will be described with reference to FIGS. 10A, FIG. 11A, and FIG. 12A, a part of the first split integrator 68 and a part corresponding to a part of the first split integrator 68 in the first micro fly's eye lens 50 are shown. Are drawn respectively.

  As shown in FIG. 10A, when the distance between the first micro fly's eye lens 50 and the first split integrator 68 is the first distance L1, the exit surface 65b of the first split integrator 68 is The exposure light EL emitted from each cylindrical lens surface 67 gradually spreads as it approaches the first micro fly's eye lens 50. The exposure light EL emitted from each cylindrical lens surface 67 is in the Z-axis direction with the cylindrical lens surface 67 emitting the exposure light EL among the cylindrical lens surfaces 54 of the emission surface 50b of the first micro fly's eye lens 50. Are incident on the cylindrical lens surface located at the same position. At this time, the exposure light EL emitted from the cylindrical lens surfaces 67 located at the same position in the Z-axis direction is uniformly incident on the entire cylindrical lens surfaces 54 of the first micro fly's eye lens 50. Therefore, as shown in FIG. 10B, the light intensity at each position in the Z-axis direction of one cylindrical lens surface 54 in the first micro fly's eye lens 50 is substantially equal to each other. The state in which the distance between the first micro fly's eye lens 50 and the first split integrator 68 is the first distance L1 is “the first split integrator 68 is located at the initial position”. And

  Further, when the interval between the first micro fly's eye lens 50 and the first split integrator 68 is the second interval L2 which is narrower than the first interval L1, as shown in FIG. The exposure light EL emitted from one cylindrical lens surface 67 on the split integrator 68 side gradually spreads as it approaches the first micro fly's eye lens 50. Most of the exposure light EL is incident on the central portion in the Z-axis direction of the cylindrical lens surface 54 that is arranged at the same position in the Z-axis direction as the cylindrical lens surface 67 that emitted the exposure light EL. That is, the exposure light EL hardly enters both end portions in the Z-axis direction of one cylindrical lens surface 54 of the first micro fly's eye lens 50. Therefore, as shown in FIG. 11B, in one cylindrical lens surface 54, the light intensity at the central portion in the Z-axis direction is higher than the light intensity at both end portions in the Z-axis direction. In FIG. 11B, the light intensity of the exposure light EL incident on one cylindrical lens surface 52 when the first split integrator 68 is located at the initial position is indicated by a broken line.

  In addition, when the distance between the first micro fly's eye lens 50 and the first split integrator 68 is a third distance L3 that is wider than the first distance L1, as shown in FIG. The exposure light EL emitted from one cylindrical lens surface 67 on the split integrator 68 side gradually spreads as it approaches the first micro fly's eye lens 50. The exposure light EL is positioned on both sides in the Z-axis direction of the cylindrical lens surface 54 disposed at the same position in the Z-axis direction as the cylindrical lens surface 67 that emitted the exposure light EL. The light is incident on both cylindrical lens surfaces 54. That is, a cylindrical lens surface 67 (hereinafter referred to as “corresponding lens surface”) corresponding to the one cylindrical lens surface 54 at the central portion in the Z-axis direction of one cylindrical lens surface 54 of the first micro fly's eye lens 50. Only the exposure light EL emitted from () enters. On the other hand, at both ends of one cylindrical lens surface 54 in the Z-axis direction, not only the exposure light EL emitted from the corresponding lens surface, but also the respective cylindrical lens surfaces 67 positioned on both sides of the corresponding lens surface in the Z-axis direction. Exposure light EL is also incident. Therefore, as shown in FIG. 12B, in one cylindrical lens surface 54, the light intensity at the central portion in the Z-axis direction is weaker than the light intensity at both end portions in the Z-axis direction. In FIG. 12B, the light intensity of the exposure light EL incident on one cylindrical lens surface 52 when the first split integrator 68 is located at the initial position is indicated by a broken line.

  Accordingly, when the split integrators 68 to 71 are located at the initial positions, the surface light sources 61a to 61d of the first pupil intensity distribution 61 formed on the illumination pupil plane 27 by the first incident light are shown in FIG. As described above, each of the plurality of point light sources 77 formed by the first optical integrator 26 is formed. In addition, each surface light source 62a to 62d of the second pupil intensity distribution 62 formed on the illumination pupil plane 27 by each second incident light is formed from a number of surface light sources formed by the first optical integrator 26, respectively. . In addition, each surface light source 62a to 62d of the second pupil intensity distribution 62 formed on the illumination pupil plane 27 by each third incident light is formed from a number of surface light sources formed by the first optical integrator 26, respectively. .

  Further, when each of the split integrators 68 to 71 moves to the + Y direction side from the initial position, each of the surface light sources 61a to 61d of the first pupil intensity distribution 61 is shown in FIG. 13 and FIG. ˜71 are formed from a large number of point light sources 78 having a higher light intensity than the point light source 77 in the case where each is located at the initial position. This is because exposure light EL (incident on the central portion in the Z-axis direction of each cylindrical lens surface 54 of the first micro fly's eye lens 50 when each split integrator 68-71 approaches the first micro fly's eye lens 50. That is, the amount of the first incident light) is increased. On the other hand, the surface light sources 62a to 62d of the second pupil intensity distributions 62 are compared with the point light sources 77 when the divided integrators 68 to 71 are located at the initial positions, as shown in FIGS. Each is formed from a large number of point light sources 79 having low light intensity. This is because exposure light EL (incident on both end portions in the Z-axis direction of each cylindrical lens surface 54 of the first micro fly's eye lens 50 when each of the split integrators 68 to 71 approaches the first micro fly's eye lens 50. That is, the light amounts of the second incident light and the second incident light are reduced.

  Further, when each of the split integrators 68 to 71 moves to the −Y direction side from the initial position, each of the surface light sources 61a to 61d of the first pupil intensity distribution 61 is positioned at the initial position. Each point light source 77 is formed from a large number of point light sources having a light intensity lower than that of the point light source 77. This is because exposure light EL (incident on the central portion in the Z-axis direction of each cylindrical lens surface 54 of the first micro fly's eye lens 50 when each split integrator 68-71 approaches the first micro fly's eye lens 50. That is, the amount of the first incident light) is reduced. On the other hand, the surface light sources 62a to 62d of the second pupil intensity distributions 62 are derived from a large number of point light sources having higher light intensity than the point light sources 77 when the divided integrators 68 to 71 are located at the initial positions. It is formed. This is because exposure light EL (incident on both end portions in the Z-axis direction of each cylindrical lens surface 54 of the first micro fly's eye lens 50 when each of the split integrators 68 to 71 approaches the first micro fly's eye lens 50. That is, the amount of the second incident light and the second incident light) is increased.

  Next, an example of an action when adjusting the pupil intensity distributions 61 and 62 corresponding to the points P1b, P2b, and P3b along the Y-axis direction in the still exposure region ER2 will be described. In the initial state, each of the split integrators 68 to 71 is assumed to be disposed at an initial position.

  When the exposure light EL emitted from the light source device 12 is incident on the diffractive optical element 19, the diffractive optical element 19 emits exposure light EL having a quadrupole cross-sectional shape. Then, the exposure light EL passes through the correction filter 24 arranged at a position optically conjugate with the illumination pupil plane 27 or in the vicinity thereof. As a result, the illumination pupil plane 27 formed on the exit side of the optical integrator 26 is almost corrected by the correction filter 24 and the first and second surface light sources 60a and 60b corrected (dimmed) by the correction filter 24. A secondary light source 60 having a third surface light source 60c and a fourth surface light source 60d that are not formed is formed. At this time, the pupil intensity distribution of the pupil conjugate plane optically conjugate with the illumination pupil plane 27 is also corrected by the correction filter 24.

  Note that the correction filter 24 of the present embodiment reduces the light intensity of the third surface light source 60c and the fourth surface light source 60d along the Z-axis direction of the secondary light source 60 formed on the illumination pupil plane 27. It is a filter. As described above, in the first pupil intensity distribution 61 corresponding to the center points P1a and P1b in the illumination area ER1 of the reticle R and in the static exposure area ER2 on the wafer W, the correction filter is included in the optical path of the exposure light EL. 24, the light intensity of the first surface light source 61a and the second surface light source 61b along the X-axis direction is greater than the light intensity of the third surface light source 61c and the fourth surface light source 61d along the Z-axis direction. Are also weak. Therefore, in the first pupil intensity distribution 61, the light intensity of the third surface light source 61c and the fourth surface light source 61d approaches the light intensity of the first surface light source 61a and the second surface light source 61b by the correction filter 24. . On the other hand, in the second pupil intensity distribution 62 corresponding to the peripheral points P2a, P2b, P3a, and P3b in the illumination area ER1 and the still exposure area ER2, the X axis is used when the correction filter 24 is not in the optical path of the exposure light EL. Each light intensity of the first surface light source 62a and the second surface light source 62b along the direction is stronger than each light intensity of the third surface light source 62c and the fourth surface light source 62d along the Z-axis direction. Therefore, in the second pupil intensity distribution 62, the difference between the light intensity of the first surface light source 61a and the second surface light source 62b and the light intensity of each of the third surface light source 62c and the fourth surface light source 62d is caused by the correction filter 24. On the contrary, it will become bigger.

  In order to make the first pupil intensity distribution 61 and the second pupil intensity distribution 62 have substantially the same distribution, the light intensity of the first surface light source 61a and the second surface light source 61b of the first pupil intensity distribution 61 is obtained. And the light intensity of the first surface light source 62a and the second surface light source 62b of the second pupil intensity distribution 62 need to be weakened. Therefore, in this embodiment, the pupil intensity distribution measuring device 36 measures the light intensity of the quadrupole pupil intensity distribution for each point in the still exposure region ER2 in the secondary light source 60 formed on the illumination pupil plane 27. Is done. Here, the first pupil intensity distribution 61 formed on the illumination pupil plane 27 by the first incident light, the second incident light, and the third incident light incident on the center point P1b and the peripheral points P2b, P3b in the still exposure region ER2. The second pupil intensity distribution 62 is measured. In this case, the first pupil intensity distribution 61 and the second pupil intensity distribution 62 have different properties.

  Then, when driving force is applied from the moving mechanisms 73 and 74 to the first split integrator 68 and the second split integrator 69 by driving of the drive sources 73a and 74a, the split integrators 68 and 69 move in the + Y direction from the initial position. Move to each side. That is, the distance between each of the split integrators 68 and 69 and the first micro fly's eye lens 50 is smaller than the first distance L 1, while the remaining split integrators 70 and 71 and the first micro fly's eye lens 50 are. Are maintained at the first interval L1. Then, the light intensities of the first surface light source 61a and the second surface light source 61b of the first pupil intensity distribution 61 gradually increase as the divided integrators 68 and 69 move to the + Y direction side. On the other hand, the light intensities of the first surface light source 61a and the second surface light source 62b of each second pupil intensity distribution 62 gradually become weaker as the divided integrators 68 and 69 move to the + Y direction side. At this time, the split integrators 70 and 71 do not move the light intensity of the third surface light sources 61c and 62c and the fourth surface light sources 61d and 62d of the first pupil intensity distribution 61 and the second pupil intensity distribution 62, respectively. Therefore, it does not change each.

  Then, when the properties of the first pupil intensity distribution 61 and the properties of the second pupil intensity distributions 62 are substantially the same, the movement of each of the split integrators 68 and 69 is stopped. In this case, the light intensity of each first incident light incident on the center point P1b of the stationary exposure region ER2 from each of the surface light sources 61a to 61d and the peripheral points P2b and P3b of the stationary exposure region ER2 from each of the surface light sources 62a to 62d. The light intensity of each incident second incident light and each third incident light is substantially the same as each other. Therefore, when the exposure process is executed in this state, the pupil intensity distributions 61 and 62 corresponding to the points P1b, P2b, and P3b along the Y-axis direction in the static exposure region ER2 on the wafer W are substantially identical. Therefore, the occurrence of variations in the line width of the pattern formed on the surface Wa of the wafer W is suppressed.

Therefore, in this embodiment, the following effects can be obtained.
(1) By changing the interval between the optical integrators 26 and 65, the light intensity of the exposure light EL incident on each position in the Z-axis direction in each cylindrical lens surface 54 of the first optical integrator 26 is changed. Adjusted. As a result, pupil intensity distributions 61 and 62 corresponding to each point on the surface Wa on the wafer W are independently adjusted. Therefore, the light intensity distribution at each point on the wafer W can be adjusted to distributions having substantially the same properties.

  (2) Further, in the present embodiment, each light source device 12 side of the first optical integrator 26 is located at a position optically conjugate with the surface Wa of the wafer W. A correction filter 24 is provided for uniformly adjusting the pupil intensity distributions 61 and 62 corresponding to the points P1b to P3b. The pupil intensity distributions 61 and 62 corresponding to the points P1b to P3b in the still exposure region ER2 are adjusted so as to be substantially uniform by the cooperation of the correction filter 24 and the second optical integrator 65, respectively. Is done. Therefore, the pupil intensity distributions 61 and 62 corresponding to the points P1b to P3b in the still exposure region ER2 can be adjusted with higher precision than when the correction filter 24 is not arranged in the optical path of the exposure light EL. Therefore, it is possible to perform exposure processing on the wafer W under an appropriate illumination condition according to the circuit pattern of the reticle R. As a result, the wafer W is faithfully provided with a pattern having a desired line width over the entire wafer W. Can be formed.

  (3) Generally, the adjustment of the pupil intensity distributions 61 and 62 corresponding to the points P1b to P3b along the Y-axis direction in the static exposure region ER2 on the wafer W is performed by adjusting the illumination pupil plane 27 or the illumination pupil plane 27. A light shielding member is disposed in the vicinity of the pupil conjugate plane that is optically conjugate with each other, and the degree of light shielding of the first incident light, the second incident light, and the third incident light that can enter each of the points P1b to P3b is corrected for each point. Each is done by In this case, the light blocked by the light blocking member is not used for exposure of the wafer W. However, in the present embodiment, the pupil intensity distributions 61 and 62 are adjusted by adjusting the intervals between the optical integrators 26 and 65, respectively. At this time, a part of the exposure light EL constituting the second pupil intensity distribution 62 before the adjustment is adjusted along the Y-axis direction in the still exposure region ER2 by adjusting the distance between the optical integrators 26 and 65. Further, it is used to form a pupil intensity distribution corresponding to other points among the points P1b to P3b. That is, in the present embodiment, the distribution correction optical system 31 can correct the pupil intensity distributions 61 and 62 corresponding to the points P1b to P3b without losing the light amount of the exposure light EL, and can perform exposure on the wafer W. Can be done. Therefore, the loss of the light amount of the exposure light EL by the distribution correction optical system 31 can be reduced, so that the pattern formation speed on the wafer W can be improved.

  (4) In the present embodiment, the pupil optical intensity distributions 61 and 62 corresponding to the points P1b to P3b are adjusted by moving the second optical integrator 65 along the Y-axis direction. Therefore, unlike the case where the first optical integrator 26 moves along the Y-axis direction, the illumination pupil plane 27 is suppressed from being displaced along the Y-axis direction. Therefore, an optical system for optically maintaining the Fourier transform relationship between the illumination pupil plane 27 and the surface Wa of the wafer W may not be separately provided on the reticle R side from the illumination pupil plane 27. That is, complication of the configuration of the illumination optical system 13 can be suppressed.

  (5) The second optical integrator 65 is composed of a plurality (four in this embodiment) of divided integrators 68 to 71. In addition, each of the split integrators 68 to 71 is provided so as to individually correspond to the surface light sources 60 a to 60 d of the secondary light source 60. Therefore, the light intensity can be corrected for each surface light source.

  (6) In the present embodiment, each of the integrators 68 to 71 corresponds to the measurement result calculated based on the detection signal from the pupil intensity distribution measuring device 36, that is, to each point P1a to P3a in the illumination region ER1 of the reticle R. And move along the Y-axis direction based on the pupil intensity distributions 61 and 62 respectively. Therefore, when each of the pupil intensity distributions 61 and 62 changes due to deterioration of at least one of the various optical elements constituting the illumination optical system 13, each division is performed according to the measurement result by the pupil intensity distribution measuring device 36. By moving the integrators 68 to 71 in the Y-axis direction, the pupil intensity distributions 61 and 62 can be quickly adjusted so that their property distributions become the desired property distributions.

  (7) The second optical integrator 65 has cylindrical lens surfaces 66 and 67 that individually correspond to the respective cylindrical lens surfaces 54 of the first micro fly's eye lens 50. Therefore, by moving the second optical integrator 65 along the Y-axis direction, the light intensity of the exposure light EL incident on each position in the Z-axis direction of each cylindrical lens surface 54 of the first micro fly's eye lens 50 is increased. The strength is adjusted. That is, the light intensity of each incident light incident on the points P1b to P3b along the Y-axis direction among the points in the still exposure region ER2 is adjusted. Accordingly, by adjusting the distance between the optical integrators 26 and 65, the pupil intensity distributions 61 and 62 corresponding to the points P1b to P3b along the Y-axis direction among the points in the still exposure region ER2 are adjusted. be able to.

The above embodiment may be changed to another embodiment as described below.
In the embodiment, the diffractive optical element 19 may be a diffractive optical element for multipole illumination (for example, for quadrupole illumination) or a diffractive optical element for annular illumination. In addition, if the optical element can change the shape of the exposure light EL, another arbitrary optical element such as an axicon lens pair is arranged instead of or in addition to the diffractive optical element 19. May be. An illumination optical system including an axicon lens pair is disclosed in, for example, International Publication No. 2005 / 076045A1 and corresponding US Patent Application Publication No. 2006 / 0170901A. In the embodiment shown in FIG. 1, an axicon lens pair can be disposed in the vicinity of the correction filter 24.

  Further, instead of the diffractive optical element 19, for example, it is composed of a large number of minute element mirrors arranged in an array and whose inclination angle and inclination direction are individually controlled to divide the incident light beam into minute units for each reflecting surface. Thus, a spatial light modulation element that converts the cross section of the light beam into a desired shape or a desired size by deflecting the light beam may be used. An illumination optical system using such a spatial light modulator is disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-353105.

  In the embodiment, an optical element having no power (for example, a plane parallel plate) may be disposed between the optical integrators 26 and 65. Even if comprised in this way, the effect equivalent to the said embodiment can be acquired.

  In the embodiment, when exposure processing is performed while the wafer W and the reticle R are respectively scanned and moved along the Y-axis direction, cylindrical lens surfaces 66A and 67A extending along the Z-axis direction are provided as shown in FIG. The second optical integrator 65A may be disposed on the incident side of the first optical integrator 26. A plurality of (10 in FIG. 16) cylindrical lens surfaces 66A individually corresponding to the respective cylindrical lens surfaces 52 of the first micro fly's eye lens 50 are formed on the incident surface 65a of the second optical integrator 65A. Each cylindrical lens surface 66A is disposed along the X-axis direction. In addition, a plurality of (10 in FIG. 16) cylindrical lens surfaces 67A individually corresponding to the respective cylindrical lens surfaces 66A are formed on the emission surface 65b of the second optical integrator 65A. , And are arranged along the X-axis direction. Even if comprised in this way, the pupil intensity distribution corresponding to each point in the X-axis direction substantially orthogonal to the scanning direction can be adjusted in the still exposure region ER2.

  In the embodiment, the width of each cylindrical lens surface 66, 67 of the second optical integrator 65A in the Z-axis direction may be wider than the first width H1 of the cylindrical lens surface 54 of the first micro fly's eye lens 50. . The initial position in this case is a position on the + Y direction side (that is, a position close to the first micro fly's eye lens 50) as compared to the case of the above embodiment.

  Further, the width in the Z-axis direction of each of the cylindrical lens surfaces 66 and 67 of the second optical integrator 65A may be narrower than the first width H1 of the cylindrical lens surface 54 of the first micro fly's eye lens 50. The initial position in this case is a position on the −Y direction side (that is, a position apart from the first micro fly's eye lens 50) as compared to the case of the above embodiment.

  In the embodiment, if the pupil intensity distribution measuring device 36 can measure the pupil intensity distributions 61 and 62 corresponding to the points P1a, P2a, and P3a in the illumination region ER1 on the reticle R, the vicinity of the reticle R Not necessarily. However, the pupil intensity distribution measuring device 36 may be installed at an arbitrary position as long as it is in the vicinity of a position optically conjugate with the irradiated surface Ra of the reticle R (that is, the surface Wa of the wafer W).

  In the embodiment, the moving mechanisms 73 to 76 may not be configured to be driven in conjunction with the measurement result by the pupil intensity distribution measuring device 36. That is, the measurement result by the pupil intensity distribution measuring device 36 is displayed on a display screen such as a monitor (not shown), and the operator moves each of the integrators 68 to 71 along the Y-axis direction based on the measurement result displayed on the display screen. You may make it move. In this case, the driving mechanisms 73a to 76a do not have to be provided in the moving mechanisms 73 to 76. That is, the split integrators 68 to 71 are moved manually by the operator.

  In the embodiment, the second optical integrator 65 may be configured not to include the third split integrator 70 and the fourth split integrator 71. In this case, of the exposure light EL emitted from the zoom optical system 25, the exposure light EL constituting the third surface light source 60c and the fourth surface light source 60d on the illumination pupil plane 27 is incident on the second optical integrator 65. Without incident, the light enters the first micro fly's eye lens 50.

  Further, the second optical integrator 65 may have a configuration in which the first split integrator 68 and the second split integrator 69 are integrated. In this case, the distribution correction optical system 31 may have a configuration having only one moving mechanism.

In the embodiment, the moving mechanisms 74 and 75 for the third split integrator 70 and the fourth split integrator 71 may not be provided.
In the embodiment, the first optical integrator 26 may be configured by one micro fly's eye lens in which unit wavefront division surfaces having refractive power are arranged along the Z direction and the X direction. . Further, as the optical integrator, a fly-eye lens in which a plurality of lens elements are arranged may be used. A pair of fly-eye mirrors in which a plurality of mirror surfaces are arranged may be used as the optical integrator.

  In the embodiment, the exposure apparatus 11 may be embodied as a maskless exposure apparatus using a variable pattern generator (for example, DMD (Digital Mirror Device or Digital Micro-mirror Device)). Such a maskless exposure apparatus is disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-304135, International Patent Publication No. 2006/080285, and US Patent Publication No. 2007/0296936 corresponding thereto.

  In the embodiment, the exposure apparatus 11 is for manufacturing a reticle or mask used not only in a micro device such as a semiconductor element but also in an optical exposure apparatus, an EUV exposure apparatus, an X-ray exposure apparatus, and an electron beam exposure apparatus. In addition, an exposure apparatus that transfers a circuit pattern from a mother reticle to a glass substrate, a silicon wafer, or the like may be used. The exposure apparatus 11 is used for manufacturing a display including a liquid crystal display element (LCD) and the like, and is used for manufacturing an exposure apparatus that transfers a device pattern onto a glass plate, a thin film magnetic head, and the like. It may be an exposure apparatus that transfers to a wafer or the like, and an exposure apparatus that is used to manufacture an image sensor such as a CCD.

  In the embodiment, the exposure apparatus 11 may be embodied as a scanning stepper that transfers the pattern of the reticle R to the wafer W in a state where the reticle R and the wafer W are relatively moved, and sequentially moves the wafer W stepwise.

In the embodiment, the light source device 12 includes, for example, g-line (436 nm), i-line (365 nm), KrF excimer laser (248 nm), F ₂ laser (157 nm), Kr ₂ laser (146 nm), Ar ₂ laser (126 nm) The light source which can supply etc. may be sufficient. The light source device 12 amplifies the infrared or visible single wavelength laser light oscillated from the DFB semiconductor laser or fiber laser, for example, with a fiber amplifier doped with erbium (or both erbium and ytterbium). Alternatively, a light source capable of supplying harmonics converted into ultraviolet light using a nonlinear optical crystal may be used.

  In the embodiment, a method of filling the optical path between the projection optical system and the photosensitive substrate with a medium (typically liquid) having a refractive index larger than 1.1, that is, a so-called immersion method may be applied. Good. In this case, as a method of filling the liquid in the optical path between the projection optical system and the photosensitive substrate, a method of locally filling the liquid as disclosed in International Publication No. WO99 / 49504, A method of moving a stage holding a substrate to be exposed as disclosed in Japanese Patent Application Laid-Open No. 6-124873 in a liquid bath, or a predetermined depth on a stage as disclosed in Japanese Patent Application Laid-Open No. 10-303114. A technique of forming a liquid tank and holding the substrate in the liquid tank can be employed.

  In the embodiment, the polarization illumination method disclosed in US Patent Publication No. 2006/0203214, US Patent Publication No. 2006/0170901, and US Patent Publication No. 2007/0146676 may be applied.

  Next, an embodiment of a microdevice manufacturing method using the device manufacturing method by the exposure apparatus 11 of the embodiment of the present invention in the lithography process will be described. FIG. 17 is a flowchart illustrating a manufacturing example of a micro device (a semiconductor chip such as an IC or LSI, a liquid crystal panel, a CCD, a thin film magnetic head, a micromachine, or the like).

  First, in step S101 (design step), function / performance design (for example, circuit design of a semiconductor device) of a micro device is performed, and pattern design for realizing the function is performed. Subsequently, in step S102 (mask manufacturing step), a mask (reticle R or the like) on which the designed circuit pattern is formed is manufactured. On the other hand, in step S103 (substrate manufacturing step), a substrate (a wafer W when a silicon material is used) is manufactured using a material such as silicon, glass, or ceramics.

  Next, in step S104 (substrate processing step), using the mask and substrate prepared in steps S101 to S104, an actual circuit or the like is formed on the substrate by lithography or the like, as will be described later. Next, in step S105 (device assembly step), device assembly is performed using the substrate processed in step S104. Step S105 includes processes such as a dicing process, a bonding process, and a packaging process (chip encapsulation) as necessary. Finally, in step S106 (inspection step), inspections such as an operation confirmation test and a durability test of the microdevice manufactured in step S105 are performed. After these steps, the microdevice is completed and shipped.

FIG. 18 is a diagram illustrating an example of a detailed process of step S104 in the case of a semiconductor device.
In step S111 (oxidation step), the surface of the substrate is oxidized. In step S112 (CVD step), an insulating film is formed on the substrate surface. In step S113 (electrode formation step), an electrode is formed on the substrate by vapor deposition. In step S114 (ion implantation step), ions are implanted into the substrate. Each of the above steps S111 to S114 constitutes a pretreatment process at each stage of the substrate processing, and is selected and executed according to a necessary process at each stage.

  When the above-mentioned pretreatment process is completed in each stage of the substrate process, the posttreatment process is executed as follows. In this post-processing process, first, in step S115 (resist formation step), a photosensitive material is applied to the substrate. Subsequently, in step S116 (exposure step), the circuit pattern of the mask is transferred to the substrate by the lithography system (exposure apparatus 11) described above. Next, in step S117 (development step), the substrate exposed in step S116 is developed to form a mask layer made of a circuit pattern on the surface of the substrate. Subsequently, in step S118 (etching step), the exposed member other than the portion where the resist remains is removed by etching. In step S119 (resist removal step), the photosensitive material that has become unnecessary after the etching is removed. That is, in step S118 and step S119, the surface of the substrate is processed through the mask layer. By repeatedly performing these pre-processing steps and post-processing steps, multiple circuit patterns are formed on the substrate.

1 is a schematic block diagram that shows an exposure apparatus in the present embodiment. The perspective view which shows a pair of micro fly's eye lens typically. The schematic diagram which shows the quadrupole secondary light source formed in an illumination pupil plane. (A) is a schematic diagram which shows the illumination area | region formed on a reticle, (b) is a schematic diagram which shows the static exposure area | region formed on a wafer. The schematic diagram which shows the 1st pupil intensity distribution formed with the incident light which injects into the center point in a still exposure area | region. The schematic diagram which shows the 2nd pupil intensity distribution formed with the incident light which injects into the peripheral point in a still exposure area | region. (A) is a graph showing the light intensity along the Z-axis direction of the first pupil intensity distribution corresponding to the center point in the still exposure area, and (b) is the second pupil intensity corresponding to the peripheral points in the still exposure area. The graph which shows the light intensity along the Z-axis direction of distribution. The front view which shows typically the distribution correction optical system in this embodiment. The perspective view which shows a 2nd optical integrator typically. (A) is a schematic diagram showing the relationship between the second optical integrator and the first micro fly's eye lens when the second optical integrator is arranged at the initial position, and (b) is the emission of the first micro fly's eye lens. The graph which shows the light intensity for every position in the Z-axis direction of the cylindrical lens surface of the side. (A) is a schematic diagram showing the relationship between the second optical integrator and the first micro fly's eye lens when the second optical integrator moves to the + Y direction side from the initial position, and (b) is the first micro fly's eye. The graph which shows the light intensity for every position in the Z-axis direction of the cylindrical lens surface of the exit side of a lens. (A) is a schematic diagram showing the relationship between the second optical integrator and the first micro fly's eye lens when the second optical integrator moves to the −Y direction side from the initial position, and (b) shows the first micro fly eye. The graph which shows the light intensity for every position in the Z-axis direction of the cylindrical lens surface of the exit side of an eye lens. The schematic diagram which shows 1st pupil intensity distribution in case a 2nd optical integrator is arrange | positioned in an initial position. The schematic diagram which shows the 1st pupil intensity distribution when the 2nd optical integrator moves to the + Y direction side from the initial position. The schematic diagram which shows the 2nd pupil intensity distribution when the 2nd optical integrator moves to the -Y direction side from the initial position. The perspective view which shows typically the 2nd optical integrator of another embodiment. The flowchart of the manufacture example of a device. The detailed flowchart regarding the board | substrate process in the case of a semiconductor device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Exposure apparatus, 12 ... Light source device, 13 ... Illumination optical system, 15 ... Projection optical system, 26 ... 1st optical integrator, 27 ... Illumination pupil plane, 36 ... Pupil intensity distribution measuring device, 40 ... Control apparatus, 42 ... aperture stop, 50a ... incident surface, 50b ... exit surface, 52,54 ... cylindrical lens surface as first unit wavefront dividing surface, 60a-60d ... surface light source as region, 65,65A ... second optical integrator, 66, 66A ... cylindrical lens surface as second unit wavefront dividing surface, 68-71 ... split integrator, 73-76 ... moving mechanism, 73a-76a ... drive source, AX ... optical axis, EL ... exposure light, P1a-P3a , P1b to P3b ... Points as predetermined points, Ra ... Irradiated surface, W ... Wafer as substrate, Wa ... Surface as irradiated surface.

Claims (13)

An illumination optical system that illuminates the illuminated surface with light from a light source,
An illumination pupil plane in the illumination optical path of the illumination optical system, having a plurality of first unit wavefront splitting surfaces arranged in a plane intersecting the optical axis of the illumination optical system, when light from the light source is incident A first optical integrator that forms a predetermined light intensity distribution on
A second optical integrator disposed on the light source side of the first optical integrator and having a plurality of second unit wavefront division planes individually corresponding to the plurality of first unit wavefront division planes;
A moving mechanism for moving at least one of the first and second optical integrators along an optical axis direction of the illumination optical system to change a distance between the first and second optical integrators; An illumination optical system comprising: The illumination optical system according to claim 1, wherein the moving mechanism moves the second optical integrator along the optical axis direction. The second optical integrator includes a plurality of split integrators having at least one second unit wavefront split surface among the plurality of second unit wavefront split surfaces.
The illumination optical system according to claim 1, wherein the moving mechanism individually moves the plurality of split integrators along the optical axis direction. In the illumination pupil plane, a plurality of regions arranged at different positions are formed by light emitted from the first optical integrator, and illumination light beams are respectively emitted from the plurality of regions. And
The illumination optical system according to claim 3, wherein the plurality of split integrators are arranged corresponding to the plurality of regions, respectively. 5. The driving mechanism according to claim 1, wherein the moving mechanism includes a driving source that drives at least one of the first and second optical integrators to move along the optical axis direction. The illumination optical system according to claim 1. A measuring device for measuring a light intensity distribution in an angular direction of a light beam reaching a predetermined point on the irradiated surface;
The illumination optical system according to claim 5, further comprising a control device that controls the drive source in accordance with a measurement result obtained by the measurement device. The plurality of second unit wavefront dividing surfaces have a size equal to that of the plurality of first unit wavefront dividing surfaces, according to any one of claims 1 to 6. The illumination optical system described. The first optical integrator includes a first cylindrical lens group arranged along a first direction in the plane intersecting the optical axis of the illumination optical system, and the surface intersecting the optical axis of the illumination optical system. A second cylindrical lens group arranged along a second direction orthogonal to the first direction,
The first unit wavefront dividing plane is defined by one cylindrical lens in the first cylindrical lens group and one cylindrical lens in the second cylindrical lens group. The illumination optical system according to claim 1. The illumination optical system according to any one of claims 1 to 8, wherein an optical element having power is not disposed between the first and second optical integrators. Used in combination with a projection optical system that forms a surface optically conjugate with the irradiated surface,
The illumination optical system according to any one of claims 1 to 9, wherein the illumination pupil plane is formed at a position optically conjugate with an aperture stop of the projection optical system. The illumination optical system according to any one of claims 1 to 10, wherein light output from a light source is guided to a predetermined pattern on the irradiated surface,
An exposure apparatus that projects an image of a pattern formed by illuminating the predetermined pattern with light emitted from the illumination optical system onto a substrate coated with a photosensitive material. A projection optical system for projecting an image of the pattern onto the substrate;
12. The exposure apparatus according to claim 11, wherein an image of the pattern is projected onto the substrate by moving the pattern and the substrate relative to the projection optical system along a scanning direction. An exposure step of exposing an image of the pattern onto the surface of the substrate using the exposure apparatus according to claim 11 or 12,
After the exposure step, the development step of developing the substrate to form a mask layer having a shape corresponding to the image of the pattern on the surface of the substrate;
And a processing step of processing the surface of the substrate through the mask layer after the developing step.

Images