JP2009041956A - Pupil transmittance distribution measuring apparatus and method, projection exposure apparatus, and device manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for measuring the pupil transmittance distribution on the exit pupil of an imaging optical system. <P>SOLUTION: The pupil transmittance distribution measuring apparatus for measuring the transmittance distribution within a surface which is in a conjugate relation to the exit pupil of the imaging optical system which allows a first surface and a second surface to be in an optically conjugate relation includes a light supply section for supplying first light which is directed to the imaging optical system via the first surface; a first illuminometer which is provided to be arranged on the first surface for measuring the radiation luminous intensity of the first light; and a second illuminometer which is provided, arranged on the second surface to measure the radiation luminous intensity of second light from the light supply section via the imaging optical system. The light supply section supplies the first light which is set in an angle range which is a part of a light flux angle range which can be captured by the imaging optical system and sets the second light, in an angle range that corresponds to the angle range of the first light. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical performance measurement technique for measuring the optical performance of a test optical system. For example, a mask pattern is formed in a lithography process for manufacturing various devices such as a semiconductor integrated circuit, a liquid crystal display element, or a thin film magnetic head. It is suitable for use in measuring pupil transmittance distribution of an imaging optical system such as a projection optical system of a projection exposure apparatus used for transferring onto a substrate.

  For example, in a lithography process for manufacturing a semiconductor integrated circuit, each pattern of a wafer (or a glass plate or the like) on which a resist (or a sensitive object) is applied as a pattern of a reticle (or a photomask or the like) as a mask is applied. In order to transfer to a shot area, a projection exposure apparatus such as a stepper type or a scanning stepper type provided with an illumination optical system and a projection optical system is used. In order to transfer the fine pattern onto the wafer W with high accuracy, it is required that the optical performance such as pupil transmittance distribution satisfies a predetermined condition in the projection optical system. For this purpose, it is first necessary to accurately measure (evaluate) the optical performance of the projection optical system, and various measuring apparatuses have been used.

For example, in order to measure the pupil luminance distribution on the exit pupil plane of the projection optical system in the projection exposure apparatus, the illumination light that has passed through the projection optical system is received by a two-dimensional optical sensor via a pinhole plate and a condensing optical system. In addition, a measuring apparatus that processes the detection signal of the two-dimensional optical sensor and measures the pupil luminance distribution on the exit pupil plane of the projection optical system has been proposed (for example, see Patent Document 1).
JP 2000-19012 A

  However, in the measurement apparatus of Patent Document 1, the pupil luminance distribution of an optical system that combines the illumination optical system and the projection optical system in the projection exposure apparatus is measured, and measurement of the pupil transmittance distribution in the projection optical system alone is not possible. It was possible.

  Therefore, an object of the present invention is to measure the pupil transmittance distribution at the exit pupil of an imaging optical system such as a projection optical system.

In order to achieve the above-described object, the pupil transmittance distribution measuring apparatus according to the first aspect of the present invention is an exit pupil of an imaging optical system in which the first surface and the second surface are in an optically conjugate relationship. A pupil transmittance distribution measuring device that measures the transmittance distribution in a plane conjugate with
A light supply unit for supplying first light directed to the imaging optical system via the first surface;
A first illuminometer provided so as to be arranged on the first surface and measuring the irradiance of the first light;
A second illuminometer provided so as to be arranged on the second surface and measuring the irradiance of the second light from the light supply unit via the imaging optical system;
With
The light supply unit supplies the first light set in a part of an angular range of a light flux that can be captured by the imaging optical system, and the second light is An angle range corresponding to the angle range of the first light is set.

In order to achieve the above-described object, a pupil transmittance distribution measuring method according to the second aspect of the present invention is an imaging optical system that optically conjugates a first surface and a second surface. A pupil transmittance distribution measuring method for measuring a transmittance distribution in a plane conjugate with an exit pupil,
A first measurement step of measuring the irradiance of the first light traveling toward the imaging optical system via the first surface;
A second measuring step of measuring the irradiance of the second light emitted to the second surface side through the imaging optical system;
With
The first light is a part of an angular range of a luminous flux that can be captured by the imaging optical system,
The second light is an angle range corresponding to the angle range of the first light.

A projection exposure apparatus according to a third aspect of the present invention is a projection exposure apparatus that projects and exposes a predetermined pattern onto a photosensitive substrate.
An illumination optical system for illuminating the predetermined pattern with light from a light source;
A projection optical system for forming an image of the predetermined pattern;
A pupil transmittance distribution measuring apparatus according to the first aspect for measuring the pupil transmittance distribution of the projection optical system;
With
A part of the light supply unit is provided in the illumination optical system.

According to a fourth aspect of the present invention, there is provided a projection exposure apparatus for projecting and exposing a predetermined pattern on a photosensitive substrate.
An illumination optical system for illuminating the predetermined pattern with light from a light source;
A projection optical system for forming an image of the predetermined pattern;
With
The projection optical system is measured by the pupil transmittance distribution measuring method according to the second aspect.

  A device manufacturing method according to a fifth aspect of the present invention includes an exposure step of transferring the pattern onto the photosensitive substrate using the exposure apparatus, and developing the photosensitive substrate to which the pattern has been transferred. And a development step for generating a mask layer having a shape corresponding to the pattern on the surface of the photosensitive substrate, and a processing step for processing the surface of the photosensitive substrate through the mask layer. To do.

  According to a sixth aspect of the present invention, there is provided a device manufacturing method comprising: an exposure step of transferring a pattern onto a photosensitive substrate using an exposure apparatus having a projection optical system; and the photosensitive substrate to which the pattern is transferred. A development step for developing and generating a mask layer having a shape corresponding to the pattern on the surface of the photosensitive substrate; a processing step for processing the surface of the photosensitive substrate through the mask layer; and And measuring the pupil transmittance distribution according to the measurement method according to the second aspect.

  A projection optical system adjustment method according to a seventh aspect of the present invention is a projection optical system adjustment method for projecting a predetermined pattern onto a photosensitive substrate, and the pupil transmittance distribution measurement according to the second aspect. Measuring the pupil transmittance distribution of the projection optical system using a method, and correcting the pupil transmittance distribution of the projection optical system based on the measured pupil transmittance distribution. To do.

  In the present invention, by dividing the irradiance on the first surface of the light beam limited to a predetermined angle range and the irradiance on the second surface of the light beam, the above-mentioned in the exit pupil of the imaging optical system. The transmittance in the range through which the light beam passes can be calculated. That is, it is possible to obtain the transmittance of each section obtained by dividing the exit pupil of the imaging optical system corresponding to the pupil transmittance distribution of the imaging optical system.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. Moreover, in description of drawing, the same code | symbol is attached | subjected and shown to the same part.

  FIG. 1 schematically shows a first embodiment of the present invention. In the first embodiment, the present invention is applied when measuring the pupil transmittance distribution of a projection optical system (imaging optical system) as a test optical system mounted on a projection exposure apparatus. The pupil transmittance distribution is measured, for example, during maintenance of the projection exposure apparatus. Here, FIG. 1A shows a state in which the illuminance meter 7 is disposed on the first surface 10 which is the object plane of the projection optical system PO, and FIG. 1B shows a second image plane of the projection optical system PO. It is a figure which shows the state which has arrange | positioned the illuminance meter 8 in the surface 20, and removed the illuminance meter 7 from the optical path.

  In the following description, the XYZ orthogonal coordinate system shown in each drawing is set, and the positional relationship of each member will be described with reference to this XYZ orthogonal coordinate system. The XYZ orthogonal coordinate system is set such that the X axis and the Y axis are parallel to the wafer W surface or the reticle surface, and the Z axis is set to a direction orthogonal to the wafer W surface or the reticle surface. In the XYZ coordinate system in the figure, the XY plane is actually set to a plane parallel to the horizontal plane, and the Z-axis is set vertically upward.

FIG. 1 shows a schematic configuration of a projection exposure apparatus according to the first embodiment. In FIG. 1, as an exposure light source 1 for supplying exposure light (illumination light) as an exposure beam, for example, an ArF excimer laser is used. A light source (wavelength 193 nm) is used. As the exposure light source 1, an ultraviolet pulse laser light source such as a KrF excimer laser light source (wavelength 247 nm), an F ₂ laser light source (wavelength 157 nm), a Kr ₂ laser light source (wavelength 146 nm), a YAG laser or a solid-state laser (semiconductor laser, etc.) ) Harmonic generation light source, ultraviolet solid light source (such as ultraviolet semiconductor laser and ultraviolet LED), or mercury lamp (such as i-line) can also be used.

  The exposure light IL composed of a substantially parallel light beam emitted from the exposure light source 1 enters the zoom lens 3 via a light beam cross-sectional shape conversion element 2 having a diffractive optical element, for example. The diffractive optical element constituting the beam cross-sectional shape conversion element 2 is formed by forming a step having a pitch of about the wavelength of the exposure light (illumination light) on the glass substrate, and diffracts the incident beam to a desired angle. Have. In the first embodiment, the light beam cross-sectional shape conversion element 2 (diffractive optical element) has a circular light intensity in its far field (or Fraunhofer diffraction region) when a parallel light beam having a rectangular cross section is incident. It has the function of forming a distribution.

  In the first embodiment, since the front focal point of the zoom lens 3 is the position of the light beam cross-sectional shape conversion element 2, a circular shape is formed on the rear focal plane of the zoom lens 3 by the light beam from the light beam cross-sectional shape conversion element 2. A light intensity distribution, that is, a light beam having a circular cross section is formed.

  In the vicinity of the rear focal plane of the zoom lens 3, the incident surface of the fly-eye lens 4 is positioned. The fly-eye lens 4 functions as an optical integrator that forms a large number of light sources based on the incident light flux. As such a fly-eye lens 4, reference can be made, for example, to JP-A-2004-56103 and US Pat. No. 6,913,373 corresponding thereto. The light beam incident on the fly-eye lens 4 is two-dimensionally divided, and multiple light sources distributed in the same circular shape as the illumination field formed by the light beam incident on the fly-eye lens 4 on the rear focal plane of the fly-eye lens 4 A surface light source composed of (secondary light source) is formed.

  In the state of FIG. 1, a measurement aperture stop 5 is disposed on the rear focal plane of the fly-eye lens 4, and the exposure light IL that has passed through the aperture stop 5 passes through the condenser optical system 6 as a mask. The illumination area of the first surface 10 where the lower surface (reticle surface) on which the reticle transfer pattern is formed should be positioned is illuminated with a substantially uniform illuminance distribution.

  As shown in FIG. 1A, when the illuminance meter 7 is disposed on the first surface 10, the illuminance meter 7 measures the irradiance of light limited by the aperture stop 5. Here, the light beam cross-sectional shape conversion element 2, zoom lens 3, fly-eye lens 4, aperture stop 5, and condenser optical system 6 can be regarded as a light supply unit that supplies light from the exposure light source 1 to the first surface 10. it can.

  Further, as shown in FIG. 1B, when the illuminance meter 7 is removed from the first surface 10 (when the illuminance meter 7 is removed from the optical path), the exposure light that has passed through the aperture stop 5 IL passes through the projection optical system PO via the condenser optical system 6 and the first surface 10, and the illumination area of the second surface 20 where the wafer W as a resist-coated substrate (photosensitive substrate) should be located. Illuminates with an almost uniform illumination distribution. Here, the first surface 10 and the second surface 20 are in an optically conjugate relationship with respect to the projection optical system PO, and when the transfer pattern is arranged on the first surface 10, the second surface An image of the pattern is formed at 20. Therefore, the first surface 10 can be called the object surface of the projection optical system PO, and the second surface 20 can be called the image surface of the projection optical system PO.

  FIG. 2 shows a schematic configuration of the illuminometer 7. Note that the configuration of the illuminometer 8 is the same as that of the illuminometer 7, and thus the description thereof is omitted here. The illuminometer 7 has an opening 7a having a predetermined size (for example, several mm in diameter), receives a substrate 7b formed of a light-shielding material, and light that has passed through the opening 7a, and enters the incident energy. And a light receiving element that outputs a photoelectric conversion signal corresponding to the amount. The illuminance meter 7 can have the same shape and size as the reticle, for example, and can be placed on the reticle stage RS of the projection exposure apparatus main body by a reticle transport mechanism (not shown).

  The illuminance meter 8 can have the same shape and the same size as the wafer W, for example, and can be placed on the wafer W stage WS of the projection exposure apparatus main body by a wafer W transfer mechanism (not shown).

  In addition, in the illuminance meters 7 and 8, in order to improve the angle characteristics (in order to make the sensitivity according to the angle of the light incident on the light receiving element relative to the light receiving element surface constant), the surface of the light receiving element or the light receiving element You may perform the surface treatment which makes the light transmissive member surface adjacent to the incident side the diffusion surface.

  Therefore, when measuring the irradiance on the first surface 10, the illuminance meter 7 is placed on the reticle stage RS using a reticle transport mechanism (not shown). When the irradiance on the second surface 20 is measured, the illuminance meter 7 is unloaded from the reticle stage RS using the reticle transfer mechanism, and the illuminance meter 8 is adjusted using a wafer W transfer mechanism (not shown). Place on wafer W stage WS.

  In the first embodiment, first, the irradiance of light through the aperture stop 5 is measured using the illuminance meter 7 disposed on the first surface 10, and the illuminance meter 7 is removed from the first surface 10. In this state, the illuminance meter 8 is arranged on the second surface 20 to measure the irradiance of light through the aperture stop 5 and the projection optical system PO. Then, by dividing these irradiances, it is possible to calculate the transmittance of the partial region in the exit pupil plane of the projection optical system corresponding to the region of the aperture of the aperture stop 5.

  Hereinafter, with reference to FIG.3 and FIG.4, the detailed description of the measurement method in 1st Embodiment is given.

  FIG. 3A shows a state of the surface light source 4 a formed on the exit surface side of the fly-eye lens 4, and FIG. 3B shows a state where the surface light source 4 a is limited by the aperture stop 5. In FIG. 3B, a surface light source limited by the aperture stop 5 is illustrated as a surface light source 4b. As shown in FIG. 3B, the aperture stop 5 in the first embodiment has a fan-shaped opening, and the surface light source formed by the fly-eye lens 4 is a quadrant-shaped surface light source 4b. Restrict to.

  3C to 3E show a state in which the focal length of the zoom lens 3 is changed and the size of the surface light source formed on the exit side of the fly-eye lens 4 is gradually increased. In order to facilitate understanding, the outer shape of the surface light source 4b in FIG. 3B is indicated by a wavy line in FIG. 3C, and the surface light source 4b in FIG. 3B is illustrated in FIG. 3D. The outer shape of the surface light source 4c in 3 (c) is indicated by wavy lines. Also, in FIG. 3 (e), the external shape of the surface light source 4b in FIG. 3 (b), the surface light source 4c in FIG. 3 (c), and the surface light source 4d in FIG. Each is indicated by a wavy line.

  FIGS. 4A to 4D are diagrams showing light intensity distributions on a surface optically conjugate with the exit pupil of the light supply unit at a predetermined point on the first surface 10, and these are the first surface. This corresponds to the angular distribution of the light intensity of the light beam incident on one predetermined point above. 4A corresponds to the state of FIG. 3B, FIG. 4B shows FIG. 3C, FIG. 4C shows FIG. 3D, and FIG. ) Corresponds to the state of FIG.

  First, the illuminance meter 7 is positioned so that the opening 7a is at the predetermined point (see FIG. 1 (a)), and the focal length of the zoom lens 3 is set so as to be in the state of FIG. 3 (b). The irradiance E11 reaching the illuminometer 7 is measured. Next, the focal length of the zoom lens 3 is changed so as to be in the state of FIG. 3C, and the irradiance E12 reaching the illuminance meter 7 arranged on the first surface is measured.

Here, the irradiance E11 is the irradiance when the light from the region shown in FIG. 4A reaches a predetermined point on the first surface, and the irradiance E12 is shown in FIG. 4B. This is the irradiance when light from the indicated area reaches a predetermined point on the first surface. When the area of the region shown in FIG. 4 (a) is S11 and the area of the region shown in FIG. 4 (b) is S12, from these irradiances E11 and E12, hatching is performed in FIG. 4 (e). E13 = E12−E11 × (S11 / S12) is the irradiance E13 when the light from the area indicated by reaches a predetermined point on the first surface.
It can be calculated by the following formula.

Similarly, if the focal length of the zoom lens 3 is changed to the state shown in FIG. 3D, and the irradiance E14 reaching the illuminometer 7 arranged on the first surface is measured, the hatching in FIG. E15 = E14−E12 × (S12 / S14) is the irradiance E15 when the light from the area indicated by the light reaches a predetermined point on the first surface.
It can be calculated by the following formula. However, S14 is the area of the region shown in FIG.

Furthermore, if the focal length of the zoom lens 3 is changed to the state shown in FIG. 3E and the irradiance E16 reaching the illuminometer 7 arranged on the first surface is measured, the hatching in FIG. E17 = E16−E14 × (S14 / S16) is the irradiance E17 when the light from the area shown reaches a predetermined point on the first surface.
It can be calculated by the following formula. However, S16 is the area of the region shown in FIG.

  Next, the illuminance meter 7 is removed from the optical path, and the illuminance meter 8 is positioned so that the opening of the illuminance meter 8 is a point conjugate with a predetermined point on the first surface 10 with respect to the projection optical system PO. The measurement is performed in the same procedure.

  At this time, the irradiance when the light from the region shown in FIG. 4A reaches the conjugate point on the second surface is irradiance E21, and the light from the region shown by hatching in FIG. Is the irradiance when the light reaches the conjugate point on the second surface 20 as irradiance E23, and the light from the area indicated by hatching in FIG. The irradiance is defined as irradiance E25, and the irradiance when light from the hatched area in FIG. 4G reaches the conjugate point on the second surface 20 is defined as irradiance E27.

  FIG. 5 shows a state in which the exit pupil of the projection optical system PO is divided into a plurality of sections. The region shown in FIG. 4A corresponds to the section ANW1, and hatching is shown in FIG. The region shown in FIG. 4 corresponds to the partition ANW2, the region shown by hatching in FIG. 4F corresponds to the partition ANW3, and the region shown in hatching in FIG. 4G corresponds to the partition ANW4.

Here, the transmittance in the section ANW1 at the exit pupil of the projection optical system PO is
E21 / E11
The transmittance in the partition ANW2 is
E23 / E13
The transmittance in ANW3 is
E25 / E15
The transmittance in ANW4 is
E27 / E17
It can be calculated by

  Next, the opening of the aperture stop 5 is rotated by 90 ° around the optical axis, and the above-described measurement operation is repeated, and transmittance is calculated for all sections of the exit pupil of the projection optical system PO.

  Thereby, the transmittance | permeability for every division which divided | segmented the exit pupil of the imaging optical system corresponding to the pupil transmittance distribution of a projection optical system can be calculated | required.

  And after changing the measurement position of the 1st surface 10 and the 2nd surface 20 by the illuminance meter 7 and 8 (position of the opening part of an illuminance meter) in the 1st surface 10 and the 2nd surface 20, the above-mentioned measurement is carried out. By doing so, it is possible to measure the pupil transmittance distribution corresponding to a plurality of image points of the projection optical system.

  In the first embodiment, since the irradiance is measured on the first surface 10 and the second surface 20 using the illuminance meters 7 and 8, high-precision measurement is not affected by the angular characteristics of the measuring instrument. Thus, the transmittance distribution can be calculated with high accuracy.

  In the first embodiment, the light intensity distribution formed in the far field by the light beam cross-sectional shape conversion element 2 is circular, but it may be annular. In this case, the irradiance subtraction operation can be omitted between the positions of the zoom lens 3.

  In the first embodiment, the aperture stop 5 having a fan-shaped (quadrant) opening is rotated around the optical axis. However, as shown in FIG. A plurality of openings (5NW, 5NE, 5SE, 5SW) having different orientations of the openings may be provided interchangeably.

  Further, as the aperture stop 5, for example, an aperture stop that can change the opening angle of the fan-shaped opening disclosed in Japanese Patent Laid-Open No. 2000-58441 and US Pat. No. 6,452,662 corresponding thereto may be used. good.

  Moreover, in the above-mentioned example, it was set as the structure which light-shields a part of surface light source formed with the fly-eye lens 4 using a fan-shaped opening part, but as shown to Fig.7 (a)-(c), The light beam cross-sectional shape conversion element 2 forms a quadrant, fan-shaped, partial ring-shaped light intensity distribution in the far field, and the quadrant, fan-shaped, partial ring-shaped without using the aperture stop 5. The surface light source may be formed. At this time, by rotating the light beam cross-sectional shape conversion element 2 itself around the optical axis, the surface light source having a quadrant, fan shape, or partial ring shape can also be rotated around the optical axis.

  In the first embodiment, the aperture stop 5 is disposed on the exit side of the fly-eye lens 4 as an optical integrator. However, even if the aperture stop 5 is located on the entrance side of the fly-eye lens 4, the It may be an incident side optical path of the eye lens 4 and a position substantially conjugate with the incident surface of the fly eye lens 4.

  A second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the aperture stop 5 is provided on the incident side optical path of the fly-eye lens 4 at a position substantially conjugate with the incident surface of the fly-eye lens 4. In FIG. 8, members having the same functions as those of the first embodiment shown in FIG.

  In FIG. 8, the exposure light from the exposure light source 1 enters the light beam cross-sectional shape conversion element 2 via the optical path bending prism FP. In the second embodiment, a light beam cross-sectional shape conversion element 2a for exposure is provided so as to be exchangeable with the light beam cross-sectional shape conversion element 2 for measurement.

  The exposure light from the beam cross-sectional shape conversion element 2 enters the zoom lens 3 via the relay optical system 30 and the zone ratio changing optical system 31 in this order. Here, the relay optical system 30 is provided such that the front focal point substantially coincides with the light beam cross-sectional shape conversion element 2 and the front focal point substantially coincides with the rear focal point of the front group. The aperture stop 5 is disposed at a position where the rear focus of the front group 30a and the front focus of the rear group 30b coincide with each other. This aperture stop 5 is provided so as to be exchangeable with another aperture stop 5a having another aperture shape.

  Further, the annular ratio changing optical system 31 is provided so that the front focal point substantially coincides with the rear focal point of the rear group of the relay optical system 30, that is, the conjugate plane of the beam cross-sectional shape conversion element 2 by the relay optical system 30. The front group 31a, the rear group 31b provided so that the front focal point substantially coincides with the rear focal point of the front group, and the rear group focal point of the front group 31a and the front focal point of the rear group 31b. An axicon system 32 is provided. The details of the axicon system 32 are described in the International Patent Publication No. WO2006 / 043458, and the description thereof is omitted here.

  By these relay optical system 30 and annular ratio changing optical system 31, a conjugate plane of the light beam cross-sectional shape conversion element 2 is formed at the front focal position of the zoom lens 3. Therefore, when the axicon system 32 is not operated, the light intensity formed in the far field of the beam cross-sectional shape conversion element 2 by the light passing through the zoom lens 3 and the optical path bending mirror FL1 obliquely provided on the exit side thereof. A light intensity distribution similar to the distribution is formed on the entrance surface of the fly-eye lens 4.

  Light from the fly-eye lens 4 illuminates the reticle blind RB with a substantially uniform illuminance distribution via the condenser optical system 6. The light from the reticle blind RB is reflected by the reticle blind imaging system 60 including the front group 60a, the rear group 60b, and the optical path bending mirror FL2 disposed between the front group 60a and the rear group 60b. One surface 10 is guided.

  In FIG. 8, the illuminometer 7 is positioned on the first surface 10 and the illuminometer 8 is positioned on the second surface 20, but the same as in the first embodiment. Furthermore, when the illuminance meter 8 measures the irradiance on the second surface, the illuminance meter 7 is retracted from the optical path. During actual exposure, reticle R is positioned on the first surface and wafer WW is positioned on the second surface.

  In the second embodiment, the surface light source formed by the fly-eye lens 4 is not limited by the aperture stop 5, but the light is shaped after being shaped by the aperture stop disposed upstream of the fly-eye lens 4. The configuration leads to the eye lens 4. Even in such a configuration, the pupil transmittance distribution of the projection optical system can be measured with high accuracy as in the first embodiment described above.

  Further, in the second embodiment, the axicon system 32 may be an axicon system having a V-shaped cross-sectional shape disclosed in, for example, the embodiments of FIGS. 10 to 24 of US Patent Publication No. US2002 / 0085276. .

  In the axicon system having the V-shaped cross-sectional shape, the far-field light intensity distribution image of the light beam cross-sectional shape converting element 2 (diffractive optical element) formed on the incident surface of the fly-eye lens 4 is in the plane orthogonal to the optical axis ( In FIG. 8, it can be moved in the YZ plane). Therefore, for example, when the far-field light intensity distribution of the beam cross-sectional shape converting element 2 (diffractive optical element) is a rectangular light intensity distribution, as shown in FIG. 9, the exit pupil plane of the projection optical system PO Can be divided into a plurality of sections in the form of a two-dimensional matrix. FIG. 9 shows the state of the exit pupil EXP on a plane conjugate with the exit pupil of the projection optical system PO.

  In each of the embodiments described above, when the obtained pupil transmittance distribution of the projection optical system is not uniform, the aperture stop position of the projection optical system, or a position optically conjugate with the aperture stop, A pupil transmittance distribution correction member can be provided.

  FIG. 10 is a diagram showing a schematic configuration of such a pupil transmittance distribution correction member 9. In FIG. 10, the pupil transmittance distribution correction member 9 includes a light-transmitting substrate 9a and correction films 9b and 9c formed on the surface of the substrate 9a and having a predetermined transmittance. As the correction films 9b and 9c, for example, a dot dense type correction film in which a thin film that is light-shielding against exposure light is distributed in the form of dots on the substrate 9a or a thickness distribution on the substrate 9a is provided. A correction film made of a light-shielding thin film can be used. Here, the light-shielding material as the material of the correction film does not need to be completely light-shielded with respect to the exposure light, and may have a function of reducing light.

  Here, the in-plane transmittance distribution of the pupil transmittance distribution correcting member 9 is determined so that the in-pupil transmittance distribution of the projection optical system obtained according to the above is substantially uniform.

  FIG. 11 is a diagram showing an example of the projection optical system PO. The projection optical system shown in FIG. 11 is disclosed, for example, in International Patent Publication No. WO2004 / 019128. The projection optical system PO of FIG. 11 forms a position optically conjugate with the first surface 10 (or the second surface 20) inside, and has a position optically conjugate with the first surface 10. A refractive first imaging optical system G1 to be formed, a catadioptric second imaging optical system G2 that forms a further conjugate position of the conjugate position by the first imaging optical system G1, and a second imaging optical system A refraction-type third imaging optical system that forms a further conjugate position of the conjugate position by G2 on the second surface 20. As the projection optical system PO, a projection optical system disclosed in, for example, International Patent Publication No. WO2005 / 069055 can be used.

  Here, an aperture stop AS is provided on the surface P3 in the third imaging optical system G3. Surfaces optically conjugate with this surface P3 are a surface P1 in the first imaging optical system G1 and a surface P2 in the second imaging optical system G2. The pupil transmittance distribution correction member 9 shown in FIG. 9 can be disposed on the surface P1 or P3 in the projection optical system PO.

  Further, in the projection optical system PO shown in FIG. 11, since the concave reflecting mirror is disposed on the surface P2 that is conjugate to the aperture stop AS, the reflectance distribution in the reflecting surface of the concave reflecting mirror is controlled. Also, the intra-pupil transmittance distribution of the projection optical system can be controlled. As a result, the transmittance distribution in the pupil of the projection optical system can be made substantially uniform. As a method for controlling the reflectance distribution, a method in which a layer made of a light-reducing material is provided on the reflecting surface of the concave reflecting mirror can be applied.

  In the above description, the intra-pupil transmittance distribution of the projection optical system is corrected uniformly for each image point of the projection optical system PO. When controlling the transmittance distribution in the pupil of the system, the pupil transmittance distribution correcting member 9 may be provided at a position deviating from the position of the aperture stop AS or the conjugate position (planes P1 to P3) of the projection optical system PO. .

  Since the pupil transmittance distribution correction member 9 has a predetermined optical path length, it is preferable to design and manufacture the projection optical system PO including the substrate 9a of the pupil transmittance distribution correction member 9 when designing and manufacturing the projection optical system PO. At this time, when correcting the pupil transmittance distribution, the substrate 9a positioned in the projection optical system PO is taken out and a correction film is provided on the substrate 9a or the substrate 9a on which the correction film is formed is projected. What is necessary is just to replace | exchange for the board | substrate (parallel plane plate) positioned in the optical system PO.

  Further, a correction film may be provided on the optical surface (refractive surface or reflective surface) of an optical member such as a lens or mirror constituting the projection optical system PO. In this case, after obtaining the pupil transmittance distribution of the projection optical system PO according to the above-described method, the optical member constituting the projection optical system PO is taken out, and the transmittance distribution for correcting the obtained pupil transmittance distribution Is formed on the extracted optical member, and the optical member on which the correction film is formed is incorporated into the projection optical system PO again.

  Even when the surface of the optical member constituting the projection optical system PO is contaminated (for example, when fogging occurs) or when the optical member is deteriorated, the pupil transmittance distribution of the projection optical system PO is uniform. Sexuality may worsen. In this case, depending on the measurement result of the pupil transmittance distribution of the projection optical system PO, the contaminated optical member may be cleaned or the optical member that has deteriorated may be replaced.

  In the above example, it is preferable to use non-polarized light (depolarized light) as light for measuring the pupil transmittance distribution of the projection optical system PO, but linearly polarized light having a polarization direction in a predetermined direction. May be used. In this case, the pupil transmittance distribution for each polarized light can be measured by performing measurement in two kinds of polarization directions orthogonal to each other.

  In addition, the measurement (and correction) of the pupil transmittance distribution described above is performed, for example, at the time of inspection of the projection optical system in the projection exposure apparatus manufacturing factory, at the time of inspection when delivering the projection exposure apparatus to the device manufacturing factory, It can be carried out during regular maintenance of the projection exposure apparatus, when the projection exposure apparatus shows an abnormality in the device manufacturing factory, and the like.

  In each of the above-described embodiments, the illumination optical system of the projection exposure apparatus incorporating the projection optical system is used to measure the pupil transmittance distribution of the projection optical system without taking the projection optical system out of the projection exposure apparatus. Therefore, the downtime of the projection exposure apparatus can be reduced.

  In each of the embodiments described above, the illuminance meter formed in the same shape as the reticle or wafer is placed on the stage using the transfer mechanism. However, a part of the reticle stage and the wafer stage (or wafer) An illuminometer may be provided in a part of a measurement stage (different from the stage).

  In the projection exposure apparatus of the above embodiment, an illumination optical system composed of a plurality of lenses, a projection optical system is incorporated in the projection exposure apparatus main body, optical adjustment is performed, and a reticle stage or wafer stage composed of a large number of mechanical parts. Is attached to the exposure apparatus main body, wiring and piping are connected, and further comprehensive adjustment (electrical adjustment, operation check, etc.) is performed. Here, the measurement of the pupil transmittance distribution according to the above-described embodiment can be performed at the time of manufacturing the projection optical system alone and at the time of adjustment after incorporation into the projection exposure apparatus main body. The projection exposure apparatus is preferably manufactured in a clean room in which the temperature, cleanliness, etc. are controlled.

  Next, a device manufacturing method using the exposure apparatus according to each of the above embodiments will be described. FIG. 12 is a flowchart showing a manufacturing process of a semiconductor device. As shown in this figure, 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 projection exposure apparatus of each embodiment, the pattern formed on the reticle R is transferred to each shot area on the wafer W (step S44: exposure process), and the development of the wafer W after the transfer is completed. That is, the photoresist to which the pattern has been transferred is developed (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 projection exposure apparatus of each embodiment is generated, and the recess penetrates the photoresist layer. It is. In step S48, the surface of the wafer W is processed through this resist pattern. The processing performed in step S48 includes at least one of etching of the surface of the wafer W or film formation of a metal film, for example. In step S44, the projection exposure apparatus of each embodiment transfers the pattern using the wafer W coated with the photoresist as the photosensitive substrate, that is, the plate P.

  FIG. 13 is a flowchart showing a manufacturing process of a liquid crystal device such as a liquid crystal display element. As shown in this figure, in the liquid crystal device manufacturing process, a pattern forming process (step S50), a color filter forming process (step S52), a cell assembling process (step S54) and a module assembling process (step S56) are sequentially performed.

  In the pattern forming step 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 projection exposure apparatus of each embodiment. In this pattern forming process, an exposure process for transferring the pattern to the photoresist layer using the projection exposure apparatus of each embodiment, development of the plate P to which the pattern has been transferred, that is, development of the photoresist layer on the glass substrate 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 in 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 of R, G, and B are arranged. 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, the pupil transmittance distribution of the projection optical system of the projection exposure apparatus is measured. However, the present invention is not limited to the measurement of the pupil transmittance distribution of the projection optical system, and is a general imaging optical system. The present invention can be applied to the measurement of pupil transmittance distribution. The pupil transmittance distribution is also known for an optical system that forms an image by combining with a predetermined imaging lens without forming an image by itself, such as an infinitely corrected microscope objective optical system. The present invention can be applied in combination with the imaging lens.

  In addition, this invention is not limited to the above-mentioned embodiment, A various structure can be taken in the range which does not deviate from the summary of this invention.

1 is a diagram schematically showing a first embodiment of the present invention. FIG. It is a figure which shows schematic structure of the illuminance meter used by embodiment. It is a figure for demonstrating the measuring method in 1st Embodiment. It is a figure for demonstrating the measuring method in 1st Embodiment. It is a figure which shows an example at the time of dividing | segmenting the exit pupil of projection optical system PO into a some division. It is a figure which shows the modification of an aperture stop. It is a figure which shows an example of the light intensity distribution formed in the far field by the beam cross-sectional shape conversion element. It is a figure which shows the 2nd Embodiment of this invention roughly. It is a figure which shows another example at the time of dividing | segmenting the exit pupil of projection optical system PO into a some division. It is a figure which shows schematic structure of a pupil transmittance distribution correction member. It is a figure which shows an example of a projection optical system. It is a flowchart which shows the manufacturing process of the semiconductor device manufactured using the exposure apparatus concerning embodiment. It is a flowchart which shows the manufacturing process of the liquid crystal device manufactured using the exposure apparatus concerning embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Exposure light source, 2 ... Light beam cross-sectional shape conversion element, 4 ... Fly eye lens, 5 ... Aperture stop, 7, 8 ... Illuminance meter, PO ... Projection optical system, 10 ... 1st surface, 20 ... 2nd surface

Claims (20)

In the pupil transmittance distribution measuring apparatus that measures the transmittance distribution in the conjugate plane with the exit pupil of the imaging optical system that optically conjugates the first surface and the second surface,
A light supply unit for supplying first light directed to the imaging optical system via the first surface;
A first illuminometer provided so as to be arranged on the first surface and measuring the irradiance of the first light;
A second illuminometer provided so as to be arranged on the second surface and measuring the irradiance of the second light from the light supply unit via the imaging optical system;
With
The light supply unit supplies the first light set in a part of an angular range of a light flux that can be captured by the imaging optical system, and the second light is A pupil transmittance distribution measuring apparatus, wherein an angle range corresponding to the angle range of the first light is set. The light supply unit sets the range of the first light passing through a plane optically conjugate with the entrance pupil of the imaging optical system to a predetermined range, and enters the imaging optical system. The pupil transmittance distribution measuring apparatus according to claim 1, further comprising an angle range setting unit that sets the first light to the partial angle range. The pupil transmittance distribution measuring apparatus according to claim 2, wherein the angle range setting unit includes a stop that can be disposed on a surface optically conjugate with the entrance pupil of the imaging optical system. The pupil transmittance distribution measuring apparatus according to claim 2, wherein the angle range setting unit includes a light beam cross-sectional shape conversion element that converts a cross-sectional shape of light from the light source into a different cross-sectional shape. 5. The pupil transmittance distribution measuring apparatus according to claim 2, wherein the angle range setting unit includes a zoom optical system. 6. The first illuminometer measures the irradiance of the first light toward the first point on the first surface;
The second illuminometer measures the irradiance of the second light toward the second point optically conjugate with the first point with respect to the imaging optical system. The pupil transmittance distribution measuring apparatus according to any one of claims 5 to 6. The first illuminometer is provided so as to be movable within the first surface,
The pupil transmittance distribution measuring apparatus according to claim 6, wherein the second illuminometer is provided so as to be movable in the second plane. The light supply unit changes the partial angle range of the first light to another angular range different from the partial angle range,
The pupil transmittance distribution measuring apparatus according to claim 1, wherein the second light has an angle range corresponding to the other angle range of the first light. In the pupil transmittance distribution measuring method for measuring the transmittance distribution in the conjugate plane with the exit pupil of the imaging optical system that optically conjugates the first surface and the second surface,
A first measurement step of measuring the irradiance of the first light traveling toward the imaging optical system via the first surface;
A second measuring step of measuring the irradiance of the second light emitted to the second surface side through the imaging optical system;
With
The first light is a part of an angular range of a luminous flux that can be captured by the imaging optical system,
The pupil transmittance measuring method, wherein the second light is in an angle range corresponding to the angle range of the first light. In the first measurement step, the irradiation illuminance of the first light is measured on the first surface,
The pupil transmittance distribution measuring method according to claim 9, wherein in the second measuring step, the irradiance of the second light is measured on the second surface. A range of the first light passing through a plane optically conjugate with the entrance pupil of the imaging optical system is set to a predetermined range, and the first light incident on the imaging optical system is It has an angle range setting process to set a part of the angle range,
The pupil transmittance distribution measuring method according to claim 9 or 10, wherein, in the first measuring step, the irradiance of the limited first light is measured. The pupil transmission according to claim 11, wherein the angle range setting step includes a light limiting step of limiting the first light in a plane optically conjugate with an entrance pupil of the imaging optical system. Rate distribution measurement method. The first light is light directed to a first point on the first surface;
The said 2nd light is a light which goes to the 2nd point optically conjugate with the said 1st point regarding the said imaging optical system, It is any one of Claim 9 thru | or 12 characterized by the above-mentioned. Pupil transmittance distribution measurement method. A third measurement step of measuring the irradiance of the third light traveling toward the imaging optical system via the first surface;
A fourth measuring step of measuring the irradiance of the fourth light emitted to the second surface side through the imaging optical system;
With
The first light is light that passes through a third point different from the first point on the first surface, and is included in an angular range of light flux that can be captured by the imaging optical system. Have some angular range,
The second light is light that is directed to a fourth point that is optically conjugate with the third point with respect to the imaging optical system, and has an angular range corresponding to the angular range of the third light. The pupil transmittance measuring method according to claim 13, comprising: An angle range changing step of changing the partial angle range of the first light to another angular range different from the partial angle range;
A fifth measuring step of measuring irradiance of the first light having the different angle range;
A sixth measurement step of measuring an irradiance of the second light having an angle range corresponding to the other angle range of the first light;
The pupil transmittance distribution measuring method according to claim 9, further comprising: In a projection exposure apparatus that projects and exposes a predetermined pattern onto a photosensitive substrate,
An illumination optical system for illuminating the predetermined pattern with light from a light source;
A projection optical system for forming an image of the predetermined pattern;
The pupil transmittance distribution measuring device according to any one of claims 1 to 8 for measuring the pupil transmittance distribution of the projection optical system;
With
A part of the light supply unit is provided in the illumination optical system. In a projection exposure apparatus that projects and exposes a predetermined pattern onto a photosensitive substrate,
An illumination optical system for illuminating the predetermined pattern with light from a light source;
A projection optical system for forming an image of the predetermined pattern;
With
A projection exposure apparatus, wherein the projection optical system is measured by the pupil transmittance distribution measurement method according to any one of claims 9 to 15. An exposure step of transferring the pattern onto the photosensitive substrate using the exposure apparatus according to claim 16 or 17,
Developing the photosensitive substrate to which the pattern is transferred, and developing a mask layer having a shape corresponding to the pattern on the surface of the photosensitive substrate;
A processing step of processing the surface of the photosensitive substrate through the mask layer;
A device manufacturing method comprising: An exposure step of transferring a pattern onto a photosensitive substrate using an exposure apparatus including a projection optical system;
Developing the photosensitive substrate to which the pattern is transferred, and developing a mask layer having a shape corresponding to the pattern on the surface of the photosensitive substrate;
A processing step of processing the surface of the photosensitive substrate through the mask layer;
Measuring the pupil transmittance distribution of the projection optical system according to the measurement method according to any one of claims 9 to 15,
A device manufacturing method comprising: In a method for adjusting a projection optical system that projects a predetermined pattern onto a photosensitive substrate,
Measuring the pupil transmittance distribution of the projection optical system using the pupil transmittance distribution measuring method according to any one of claims 9 to 15;
And a step of correcting the pupil transmittance distribution of the projection optical system based on the measured pupil transmittance distribution.

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