JP2004289172A - Illumination optical system, aligner using same, and device manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illumination optical system that improves a light intensity distribution on an illuminated surface and that improves light quantity loss and the lowering of the throughput. <P>SOLUTION: The illumination optical system, which uses a practically incoherent beam from a light source section to illuminate a surface to be illuminated, is composed of a first optical element whose cross-section perpendicular to the optical axis is formed by plural first sides, and has a first light integrator for evenly illuminating the illuminated surface and a second light integrator for evenly illuminating the first integrator using a practically incoherent beam from the light source. The outlines of the first light integrator's illumination range at the plane of incidence are composed of multiple second sides, each of which is not parallel with respect to any of the first sides. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an illumination device that illuminates a surface to be illuminated using light from a light source, and more particularly to a lithography process for manufacturing a semiconductor element, a liquid crystal display element, an imaging element (such as a CCD) or a thin-film magnetic head. The present invention relates to an exposure apparatus for illuminating a mask or a reticle on which a pattern is drawn (the terms are used interchangeably in the present application).

  In recent years, the demand for miniaturization of semiconductor elements has been increasing more and more, and the minimum line width of line and space has fallen below 0.15 μm and is approaching 0.10 μm. In order to achieve miniaturization, in addition to shortening the wavelength of the exposure light and increasing the NA of the projection lens, an effective light source that is uniform in the illuminance for illuminating the mask and the angular distribution of the exposure light for illuminating the mask and wafer Uniform distribution is also important.

  An illumination device using two or more fly-eye lenses (including a combination of a glass rod lens or a cylindrical lens) as an optical system for uniformly illuminating the mask with uniform illuminance and for uniformizing the effective light source distribution. 2. Description of the Related Art An illumination device using an internal reflection member and a fly-eye lens has been used conventionally. In these, an effective light source is provided in which the rear fly-eye lens uniformly illuminates the mask surface to make the illuminance uniform, and the front fly-eye lens or the internal reflection member uniformly illuminates the rear fly-eye lens. The goal is to achieve uniformity.

  A light beam having a uniform light intensity distribution and a sharp edge of the distribution is incident on the incident surface of the fly-eye lens at the latter stage of the optical system. However, when the end of the light intensity distribution of the incident light reaches only a part of the rod lens constituting the fly surface lens, uneven illuminance occurs. This problem will be described with reference to FIGS. Here, FIG. 14 is a schematic plan view showing the relationship between the incident surface of the fly-eye lens and the incident light incident thereon. FIG. 15 is a cross-sectional view on the vertical axis of FIG. 14, and is a schematic diagram showing a relationship between a fly surface lens at the subsequent stage, a light intensity distribution of incident light, and a light intensity distribution on a surface to be illuminated.

  As shown in FIG. 14 and FIG. 15, the fly-eye lens 20 is composed of rod lenses 26a to 26e represented by five thick lines (hereinafter, unless otherwise specified, the reference numeral 26 is a general description of these). And receives the incident light 10. In FIG. 14, the rod lens 26 has a square cross section perpendicular to the optical axis, but may have a hexagonal shape or another cross sectional shape as described later. The shape of the light intensity distribution 12 is also square for simplicity.

  When a secondary light source is formed on the exit surface 24 of the fly-eye lens 20 and light from the secondary light source illuminates the illuminated surface 40 via the condenser lens 30, the incident surface 22 of the fly-eye lens 20 Is optically conjugate with the illuminated surface 40 (that is, in a positional relationship between the object plane and the image plane). Therefore, the light intensity distribution on the illuminated surface 40 is formed by superimposing the light intensity distribution on the incident surface 22 of each rod lens 26 on the illuminated surface 40.

  The incident light 10 has light intensity distributions 12a to 12e corresponding to the rod lenses for convenience (hereinafter, unless otherwise specified, the reference numeral 12 is a general description thereof), and the rod lenses 26a and 26e include one of them. It is understood that the incident light 10 corresponding to the light intensity distributions 12a and 12e enters only the portion.

  As described above, when the end of the light intensity distribution 12 of the incident light 10 entering the fly-eye lens 20 crosses the rod lens, the five light intensity distributions 52a to 52e written on the right of the illumination target surface 40 are superimposed. A light intensity distribution 50 is formed on the illuminated surface 40. Since the light intensity distributions 12a and 12e incident on the rod lenses 26a and 26e at both ends are cut off halfway, light intensity distributions 52a and 52e are formed on the illuminated surface 40, and the light intensity distribution 50 to be synthesized is This results in a non-uniform light intensity distribution in which the portion 53 is missing. As can be seen from the configuration of the fly-eye lens shown in FIG. 14, the rod lenses 26 are aligned in the direction perpendicular to the plane of FIG. Will be further emphasized.

  As an actual example of the light intensity distribution 50, FIGS. 17 and 18 show the results of the illuminance distribution on the illuminated surface 40 when the end of the light intensity distribution 10 entering the fly-eye lens 20 crosses the rod lens 26. . Here, FIG. 17 shows an illuminance distribution on the illuminated surface 40 when the rod lens 26 has a square cross-sectional shape because the illuminated surface 40 is a square illumination area. FIG. 18 shows the illuminance distribution on the illuminated surface 40 when the rod lens 26 has a hexagonal cross-sectional shape because the illuminated surface 40 is a hexagonal or circular illumination area. FIGS. 17 and 18 each show that the darker the portion, the lower the illuminance, and it can be understood that the illuminance distribution is non-uniform due to the end of the incident light intensity distribution. 17 and 18 are attached with color drawings in order to facilitate understanding of the present invention.

  As one means for solving this problem, as shown in FIGS. 19A and 19B, a stop 60a or 60b is arranged near the entrance surface 22 of the fly-eye lens 20 to block the light intensity distributions 12a and 12e. It is possible to do. Here, FIGS. 19A and 19B are plan views of the diaphragms 60a and 60b, respectively. The diaphragm 60a has a hollow rectangular shape formed by the outer contour line 62a and the inner contour line 64a, and the diaphragm 60b has a hollow shape formed by the outer contour line 62b and the inner contour line 64b. The shape of the light intensity distribution 12 of the incident light 10 has a square shape, and the outline is vignetted by the diaphragms 60a and 60b as shown in FIG. As a result, the end of the light intensity distribution does not cross the rod lens 26 and is located at the boundary of the rod lens 26.

Several techniques related to these have been conventionally proposed (for example, refer to Patent Documents 1 to 4).
JP-A-11-150051 JP 06-013289 A JP 08-008168 A JP-A-05-259029

  However, the conventional method of improving the uniformity of the light intensity distribution on the surface to be illuminated has a problem that the illuminance and the throughput of the mask or wafer as the surface to be illuminated are reduced, and the cost of the product is increased. Was.

  That is, if a stop is provided on the entrance surface of the fly-eye lens in order to increase the uniformity of the light intensity distribution on the surface to be illuminated, vignetting of light rays by the stop occurs, resulting in a loss of light amount.

  Therefore, an object of the present invention is to provide an illumination apparatus that improves the light intensity distribution on the surface to be illuminated and also reduces the loss of light amount and the decrease in throughput, an exposure apparatus having the illumination apparatus, and a device manufacturing method.

  In order to achieve the above object, an illumination device according to the present invention includes a first optical element in which a cross section perpendicular to an optical axis is formed by a plurality of first sides to uniformly illuminate a surface to be illuminated. Of the first light integrator, and the light intensity distribution shape formed by the light beam incident on the first light integrator on the incident surface of the first light integrator is not parallel to any of the first sides. A second cross section perpendicular to the optical axis is formed by a plurality of second sides that are not parallel to each other, or a plurality of second sides that are not parallel to any of the first sides. And a second light integrator for uniformly illuminating the first light integrator.

  A first light integrator having a plurality of first symmetry axes and a first optical element having a first cross-sectional shape perpendicular to the optical axis, and a first light integrator for uniformly illuminating a surface to be illuminated; The second cross-sectional shape of the light intensity distribution formed by the light beam incident on the first light integrator on the incident surface of the first light integrator is asymmetric with respect to any of the first symmetry axes. Or a second optical element having a second cross-sectional shape perpendicular to the optical axis so as to be asymmetric with respect to any of the first symmetry axes, and uniformly illuminates the first light integrator. And a second light integrator.

  In any of these illumination devices, the position where the end of the light intensity distribution is applied to the incident surface of the first light integrator slightly shifts with respect to a plane parallel to the optical axis. For this reason, the unevenness of the illuminance due to the end of the light intensity distribution on the illuminated surface is reduced. Ideally, in FIG. 15 described above, the positions of the light intensity distributions 12a and 12e are shifted (for example, gradually outward or inward) with respect to the rod lens rows aligned in a direction perpendicular to the paper surface, so that the illuminated surface This corresponds to the fact that the light intensity distributions 52a and 52e in 40 are shifted (gradually inward or outward) and the concave portions 53 of the light intensity distribution 50 become smaller. However, in practice, the shape of the light intensity distribution 10 also changes with respect to the rod lens array aligned in the direction perpendicular to the plane of the paper, so that the light intensity distributions 52a and 52e are completely displaced but are not superimposed.

  Further, the above-described lighting device only changes the relative position of the two integrators, and eliminates the need to provide a stop before the first integrator, thereby preventing loss of light amount and reduction in throughput. In addition, the above-described illumination device is preferable if the incident surface of the first integrator and the incident surface of the second integrator are substantially optically conjugate because optical loss due to blurring and reduction in throughput can be prevented.

  The first optical element is, for example, a rod lens having a hexagonal cross section or a quadrangular cross section, and the first light integrator is a fly-eye lens. For example, if the surface to be illuminated is rectangular as in a typical mask surface, the rod lens of the first fly-eye lens is rectangular to reduce vignetting of illumination light. A rod lens having a hexagonal cross section is particularly preferable in a triple integrator configuration described later.

  When the first optical element is a rod lens having a hexagonal cross section and the first light integrator is a fly-eye lens, the second side is about 15 degrees with respect to any one of the first sides. Or the second cross-sectional shape has a second axis of symmetry that forms an angle of about 15 degrees with any of the first axes of symmetry. This is because the regular hexagon has an axis of symmetry every 30 degrees, and if it is displaced by about 15 degrees therebetween, the positions of the rod lenses crossed by the end of the light intensity distribution are not the same for each rod lens row.

  Similarly, when the first optical element is a rod lens having a quadrangular cross section and the first light integrator is a fly-eye lens, the second side is approximately one of the first sides. Including the sides at an angle of 22.5 degrees, the second cross-sectional shape has a second axis of symmetry at an angle of about 22.5 degrees to any of the first axes of symmetry. This is because the square has an axis of symmetry every 45 degrees, and if it is displaced by about 22.5 degrees therebetween, the positions of the rod lenses crossed by the end of the light intensity distribution are not the same for each rod lens row.

  The second light integrator is, for example, a fly-eye lens having a rod lens having a square cross section. For example, if the light source is a laser light source, a rectangular shape in cross section corresponding to the shape of the incident light is preferable.

  The illuminated surface is substantially uniformly illuminated using a secondary light source formed on the exit surface of the first light integrator. Alternatively, the illumination device further includes a third light integrator, the illuminated surface is an incident surface of the third light integrator, and a secondary light source formed on an emission surface of the third light integrator. Is used to illuminate another illuminated surface almost uniformly. The present invention is suitable for such a double integrator configuration or a triple integrator configuration.

  In particular, in the case of a triple integrator, for example, if another surface to be illuminated is a square like a typical mask surface, the rod lens of the third fly-eye lens becomes a square to reduce vignetting of illumination light. The rod lens of the first fly-eye lens becomes a hexagon or a quadrangle in order to make the effective light source shape having a predetermined illumination condition (for example, coherence factor σ) for the third fly-eye lens into a circle. In order to cut out a circular illumination area, a hexagon is preferable in terms of light use efficiency.

  An exposure apparatus according to another aspect of the present invention includes the above-described illumination device and a projection optical system that projects a pattern formed on a reticle or a mask onto an object to be exposed. This exposure apparatus can also make the effective light source distribution of the reticle or mask as the illuminated surface or the another illuminated surface and the object to be exposed similar to the illumination device described above.

  A device manufacturing method according to still another aspect of the present invention includes a step of projecting and exposing the object to be exposed using the above-described exposure apparatus, and a step of performing a predetermined process on the object to be exposed and projected. Have. The claims of the device manufacturing method having the same operation as that of the above-described exposure apparatus extend to the device itself as an intermediate and final product. Such devices include, for example, semiconductor chips such as LSI and VLSI, CCDs, LCDs, magnetic sensors, thin-film magnetic heads, and the like.

  The illumination optical system of the present invention includes a first optical system that illuminates a plurality of light collection systems of an optical integrator with light from a light source, and a second optical system that illuminates a surface to be illuminated with light beams from the plurality of light collection systems. Having an optical system, a plurality of light fluxes from a part of the plurality of light-collecting systems respectively illuminate the entire illuminated surface, and from the remaining light-collecting systems of the plurality of light-collecting systems. In an illumination optical system in which a plurality of light beams respectively illuminate only a part of the illuminated surface, illumination ranges of the plurality of light beams which illuminate only a part of the illuminated surface are different from each other.

  Also, an illumination having a first optical system for illuminating a plurality of condensing systems of an optical integrator with light from a light source, and a second optical system for illuminating a surface to be illuminated with light beams from the plurality of condensing systems. In the optical system, a plurality of sides forming an outline of an illumination range in which a light beam from the first optical system illuminates an incident surface of the optical integrator, and an outline of an incident surface of each of the plurality of light collecting systems are formed. The plurality of sides are non-parallel to each other. Further, the plurality of condensed light beams are focused on a plurality of symmetry axes and a plurality of straight lines parallel to each of the plurality of symmetry axes in an illumination range in which a light beam from the first optical system illuminates an incident surface of the optical integrator. Each system is characterized by being asymmetric.

  In the illumination optical system, the position where the end of the light intensity distribution is applied on the incident surface of the first optical integrator is slightly shifted with respect to a plane parallel to the optical axis. For this reason, the unevenness of the illuminance due to the end of the light intensity distribution on the illuminated surface is reduced. Further, it is preferable that only the relative positions of the two integrators be changed, and the necessity of providing an aperture before the first integrator is eliminated, so that loss of light amount and decrease in throughput can be prevented.

  The illumination optical system of the present invention includes a first optical system that illuminates a plurality of light collection systems of an optical integrator with light from a light source, and a second optical system that illuminates a surface to be illuminated with light beams from the plurality of light collection systems. An illumination optical system having an optical system, wherein the first optical system has a first light integrator having a plurality of light collecting systems, and forms an outline of an incident surface of each light collecting system of the light integrator. A plurality of sides and a plurality of sides forming an outline of an incident surface of each light condensing system of the first optical integrator are non-parallel to each other. In any of these illumination optical systems, the position where the end of the light intensity distribution is applied to the plane of incidence of the first optical integrator slightly shifts with respect to a plane parallel to the optical axis. For this reason, the unevenness of the illuminance due to the end of the light intensity distribution on the illuminated surface is reduced.

  The illumination optical system of the present invention includes a first optical system that illuminates a plurality of light collection systems of an optical integrator with light from a light source, and a second optical system that illuminates a surface to be illuminated with light beams from the plurality of light collection systems. An illumination optical system having an optical system, wherein the first optical system has a first light integrator having a plurality of light collecting systems, and the second optical system has a plurality of light collecting systems. A plurality of sides forming an outline of an incident surface of each light condensing system of the light integrator, and a plurality of sides forming an outline of an incident surface of each light condensing system of the first light integrator. Are not parallel to each other, and the light incident surface of the light integrator and the light incident surface of the second light integrator are optically non-conjugated to each other. The light incident surface of the light 2 integrator and the illuminated surface are optically conjugate with each other. The illumination optical system is preferable if the incident surface of the first integrator and the incident surface of the second integrator are optically conjugate, since it is possible to prevent optical loss and reduction in throughput due to blurring.

  Other objects and further features of the present invention will become apparent from the preferred embodiments described below with reference to the accompanying drawings.

  ADVANTAGE OF THE INVENTION According to the illuminating device of this invention, the exposure apparatus which has the said illuminating device, and a device manufacturing method, the light intensity distribution of an illuminated surface can be improved, and the light quantity loss and the fall of a throughput can be improved.

  Hereinafter, an exposure apparatus 1 and an illumination apparatus 100 according to one aspect of the present invention will be described with reference to the accompanying drawings. Here, FIG. 10 is a schematic diagram showing a simplified optical path of the exposure apparatus 1. The exposure apparatus 1 has an illumination device 100, a reticle 200, a projection optical system 300, and a plate 400. FIG. 1 is a schematic diagram illustrating a simplified optical path of an example of the illumination device 100.

  The exposure apparatus 1 of this embodiment is a projection exposure apparatus that exposes a circuit pattern formed on a mask 200 to a plate 400 by a step-and-scan method, but the present invention applies a step-and-repeat method or another exposure method. Can be. Here, in the step-and-scan method, the plate is continuously scanned with respect to the mask to expose the mask pattern to the plate, and after the exposure of one shot is completed, the plate is step-moved to the exposure area of the next shot. This is a moving exposure method. The step-and-repeat method is an exposure method in which the plate is step-moved every time one shot of the plate is exposed, and the next shot is moved to an exposure area.

  The illuminating device 100 illuminates the reticle 200 on which the transfer circuit pattern is formed without unevenness in illuminance and uniformly with the effective light source distribution, and includes a light source unit and an illumination optical system. The light source unit includes a light source 110 and a beam shaping optical system 120.

The light source 110, in this embodiment, an ArF excimer laser with a wavelength of about 193 nm, KrF excimer laser with a wavelength of approximately 248 nm, a laser light source such as _{F 2} excimer laser having a wavelength of about 157 nm. However, the type of the light source 110 of the present invention is not limited to an excimer laser. For example, a YAG laser may be used, and the number of lasers is not limited. Further, as the light source, for example, an ultra-high pressure mercury lamp, a xenon lamp, or the like having an output of generally 500 W or more may be used. The laser 110 may be a g-line (wavelength of about 436 nm) or an i-line (wavelength of about 365 nm) of a mercury lamp.

  The beam shaping optical system 120 can use, for example, a beam expander including a plurality of cylindrical lenses, and converts the aspect ratio of the cross-sectional shape of the parallel light from the laser light source 110 to a desired value (for example, , From a rectangular shape to a square shape, etc.) to form a desired beam shape. The beam shaping optical system 120 forms a light beam having a size and a divergence angle necessary for illuminating a fly-eye lens 150 described later.

  Although not shown in FIG. 1, the light source unit preferably uses an incoherent optical system that makes a coherent laser beam incoherent. The incoherent optical system, for example, splits an incident light beam into at least two light beams (for example, p-polarized light and s-polarized light) at a light splitting surface, and then splits one of the light beams through an optical member with respect to the other light beam. It is possible to configure a folding system in which an optical path length difference equal to or longer than the coherence length of light is given, and then the light is re-guided to the divided surface so as to be superposed on the other light beam and emitted.

  The illumination optical system illuminates the mask 200 and has fly-eye lenses 130 and 150 and condenser lenses 140 and 160. Thus, the illumination optical system of the present embodiment employs a double integrator configuration having two light integrators.

  The fly-eye lenses 130 and 150 are wavefront splitting light integrators having a function of uniformly illuminating the irradiated surface, dividing the wavefront of the incident light to form a plurality of light sources on or near the light emitting surface. . The fly-eye lenses 130 and 150 convert the angle distribution of the incident light into a position distribution and emit the light, and the respective incident surfaces 132 and 152 of the fly-eye lenses 130 and 150 and the emission surfaces 134 and 154 have a Fourier transform relationship. (In the present specification, the relationship of the Fourier transform means the relationship optically between the pupil plane and the object plane (or image plane) and between the object plane (or image plane) and the pupil plane). Thus, the vicinity of the exit surfaces 134 and 154 of the fly-eye lenses 130 and 150 is a secondary light source.

  In the present embodiment, the fly-eye lenses 130 and 150 are configured by combining a large number of rod lenses (that is, minute lens elements). However, the wavefront splitting type light integrator to which the present invention can be used is not limited to the fly-eye lens. For example, a plurality of sets of cylindrical lens arrays in which each set is orthogonal to each other as shown in FIG. It may be a plate or the like. Also, a fly-eye lens in which the rod lens has three or more refracting surfaces may be used.

  Here, the cylindrical lens array plate is formed by stacking two sets of cylindrical lens array (or lenticular lens) plates. In FIG. 21 (a), the first and fourth sets of cylindrical lens array plates 211 and 214 have a focal length f1, and the second and third sets of cylindrical lens array plates 212 and 213 have f1. Has a different focal length f2. The same set of cylindrical lens array plates are arranged at the focal position of the other party. The two sets of cylindrical lens array plates are arranged so that their generatrix directions are at right angles to each other, and produce light beams having different F-numbers (that is, focal length of lens / effective aperture) in orthogonal directions. Needless to say, the number of sets is not limited to two. Further, as long as a plurality of cylindrical lenses whose generatrix directions are orthogonal to each other are used, the number of cylindrical lenses may be any. In FIG. 21B, which is a view of the combination of the cylindrical lenses of FIG. 21 seen from the optical axis direction (vertical direction in FIG. 21A), the cylindrical lenses 211 and 212 in FIG. , 213, 214 (hereinafter, referred to as a light splitting region) are referred to as “first optical element”, “second optical element”, and “light collecting area” in the claims. The sides forming the respective light splitting regions correspond to the “first side”, “second side”, and “incident surfaces of a plurality of light-collecting systems” in the claims. It corresponds to "a plurality of sides to be formed" and words similar thereto.

  The fly-eye lens 130 is provided to uniformly illuminate the fly-eye lens 150. The fly-eye lens 150 is provided to uniformly illuminate the mask 200.

  The rod lens of the fly-eye lens 130 has a square cross section in this embodiment, and the rod lens of the fly-eye lens 150 has a square or hexagonal cross section in this embodiment. Here, the section is a section related to a plane perpendicular to the optical axis. The shape of the rod lens of the fly-eye lens 130 corresponds to the shape of the light beam that has passed through the beam shaping optical system 120, and can form a rectangular angular distribution. The shape of the rod lens of the fly-eye lens 150 is a rectangle when the shape of the mask 200 is rectangular, and a circle is cut out from a hexagon rather than a circle when the shape of the mask 200 is circular. It has a hexagonal shape because it is more efficient.

  The entrance surface 132 of the rod lens constituting the fly-eye lens 130 and the entrance surface 152 of the fly-eye lens 150 are substantially conjugate. As a result, it is possible to prevent a light amount loss and a decrease in throughput due to blurring.

  Hereinafter, referring to FIG. 2, the light intensity distribution of the substantially uniform illumination light that illuminates the incident surface 152 using the incident surface 152 of the fly-eye lens 150 and the exit surface 134 of the fly-eye lens 130 as secondary light sources will be described. The relationship with the shape will be described. Here, FIG. 2A is a plan view showing the relationship between the incident surface 152 and incident light when the fly surface lens 150 has a rod lens 156 having a square cross section. FIG. 2B is a plan view illustrating a relationship between the incident surface 152 and the incident light when the fly surface lens 150 has a rod lens 156b having a hexagonal cross-sectional shape.

  As described above, the shape of the rod lens 136 of the fly-eye lens 130 is a square, and the contour shape of the light intensity distribution of the illumination light for illuminating the incident surface 152 with the vicinity of the exit surface 134 as a secondary light source is a square 138. Become.

  In the present embodiment, each side of the square 138 is not parallel to any side of the square which is the cross-sectional shape of the rod lens 156a shown in FIG. 2A, or the side of the rod lens 156b shown in FIG. It is not parallel to any side of the hexagonal cross section. Although the shape of the rod lens 136 is not shown for convenience of drawing, since this shape is equal to the square 138 divided into 5 rows and 5 columns, each side of the square which is the cross-sectional shape of the rod lens 136 is shown. Is not parallel to any of the sides of the square which is the cross-sectional shape of the rod lens 156a shown in FIG. 2 (a) or is not parallel to any of the sides of the hexagon which is the cross-sectional shape of the rod lens 156b shown in FIG. 2 (b). Not parallel.

  Next, focusing on the symmetry axis, as shown in FIG. 3 (a), the square has symmetry axes at 45 ° intervals, and as shown in FIG. 3 (b), the regular hexagon at 30 ° intervals. There is an axis of symmetry. Here, FIG. 3 is a plan view for explaining the symmetry axes of the square and the regular hexagon. The square 138 is asymmetric with respect to any axis of symmetry of the rod lens 156a shown in FIG. 2A, and is asymmetric with respect to any axis of symmetry of the rod lens 156b shown in FIG. 2B.

  In the present embodiment, the square 138 as the light intensity distribution shape forms approximately 22.5 ° with any side of the rod lens 156a, and forms 15 ° with any side of the rod lens 156b. Since the square has a symmetry axis every 45 degrees, if it is shifted by about 22.5 degrees therebetween, the positions of the rod lenses crossed by the ends of the light intensity distribution ("illumination range" in the claims) are not the same for each rod lens row. Gone. Here, any one of the plurality of sides forming the light intensity distribution and the plurality of sides forming the incident surface of the rod lens (in the case of a cylindrical lens, the light dividing area shown in FIG. 21B). The angle formed by any one of the sides is not limited to 22.5 degrees, and substantially the same effect can be obtained if the angle is 18 degrees or more and 30 degrees or less. In addition, when one or both of the shape of the light intensity distribution and the shape of the incident surface of the rod lens are regular hexagons, the regular hexagon has a symmetry axis every 30 degrees, so that a plurality of light intensity distributions are formed. If the angle between any one of the sides and any one of the plurality of sides forming the incident surface of the rod lens is about 15 degrees, the position of the rod lens at which the end of the light intensity distribution crosses Is not the same for each rod lens row. Here, the angle between the two is not limited to 15 degrees, and substantially the same effect can be obtained if it is 12 degrees or more and 20 degrees or less.

  If necessary, a stop (not shown) is provided near the exit surface 154 of the fly-eye lens 150. The diaphragm is a variable aperture diaphragm that blocks unnecessary light to form a desired secondary light source, and various types of diaphragms such as a circular aperture diaphragm and annular illumination can be used. In order to change the variable aperture stop, for example, it is possible to use a disk-shaped turret on which these stops are formed, and to rotate a turret so that a control unit and a drive mechanism (not shown) switch the aperture.

  The condenser lens 140 superimposes the light emitted from the fly-eye lens 130 on the incident surface 152 of the fly-eye lens 150 to uniformly illuminate the fly-eye lens 150. Since the diaphragms 60a and 60b do not exist between the condenser lens 140 and the fly-eye lens 150, it is possible to prevent a loss of light amount and a decrease in throughput due to the diaphragm. The condenser lens 160 superimposes the light emitted from the fly-eye lens 150 on the surface of the mask 200 and uniformly illuminates the surface of the mask 200.

  If necessary, a masking blade (aperture or slit) for controlling the exposure area during scanning is provided. In this case, the condenser lens 160 collects as much as possible the light that has been wavefront-divided by the fly-eye lens 150 and superimposes the light with a masking blade so that the masking blade is uniformly Koehler-illuminated. The masking blade and the emission surface 154 of the fly-eye lens 150 are arranged in a Fourier transform relationship, and are arranged in a substantially conjugate relationship with the mask 200 surface. The exposure apparatus 1 can further have a variable width slit for controlling uneven illuminance, if necessary.

  For example, the masking blade has a substantially rectangular opening when the projection optical system 300 is a lens type, and has an arc-shaped opening when the projection optical system 300 is an Offner-type reflection mirror system. The light beam transmitted through the opening of the masking blade is used as illumination light for the mask 200. The masking blade is an aperture whose opening width can be automatically changed, and makes it possible to change a transfer area (of an opening slit) of a plate 400 described later in the vertical direction. Further, the exposure apparatus 1 may further include a scan blade having a structure similar to the above-described masking blade, which can change the lateral direction of a transfer area (as a one-shot scan exposure area) of the plate 400. The scan blade is also an aperture whose aperture width can be automatically varied, and is provided at a position optically substantially conjugate with the mask 200 surface. Thus, the exposure apparatus 1 can set the size of the transfer area according to the size of the shot to be exposed by using these two variable blades.

  According to the illuminating device 100 of the present embodiment, the light use efficiency on the mask 200 surface, which is the illuminated surface, is high, the effective light source distribution is substantially uniform, and the illuminance distribution on the mask 200 surface can be substantially uniform.

  As shown in FIG. 14, a plurality of rod lenses having the ends of the light intensity distribution 12 on the incident surface of the fly-eye lens 20 are arranged in the vertical and horizontal directions. In FIG. 14, the rod lens illuminated in the same state as the end 12e of the light intensity distribution 12 (state in which only the upper side of the rod lens is illuminated) is from the left in the bottom row of FIG. There are 2nd, 3rd, 4th and 3 out of 25 rod lenses.

  Therefore, the light intensity distribution 50 on the illumination target surface 40 is as shown in FIG. FIG. 15 is a cross-sectional view of the optical system on a plane including a straight line passing through 12a, b, c, d, and e of FIG. 14 and the optical axis. FIG. 16 shows a plan view of the light intensity distribution 50. (However, the number of rod lenses is 5 × 5 = 25 in FIG. 14, but 4 × 4 = 16 in FIG. 16. However, since it is a diagram for explaining the principle, the number of rod lenses is It is clear that the light intensity distribution is the same regardless of the number, and the same can be said for FIGS. 17 and 18.) FIG. 16 corresponds to FIG. FIG. 16 attaches a color drawing to the present application to facilitate understanding of the present invention. The numbers in FIG. 16A indicate the number of additions of the light intensity distribution of each rod lens 26. In order to facilitate understanding, the number of typical overlaps in FIG. 16B is superimposed on the illumination area. FIG. 16 shows that the deviation from the fly-eye lens located in front of the fly-eye lens 20 is 0 degree, and the sides of the cross-sectional shapes of the rod lenses of both fly-eye lenses are parallel to each other.

On the other hand, the rod lens 156a to which the end of the light intensity distribution 138 on the incident surface 152 of the fly-eye lens 150 is not fixed in the vertical and horizontal directions shown in FIG. For example, the end of the light intensity distribution 138 is applied to the second, third, and fourth rod lenses 156a from the right at the bottom, while the first, fifth, and sixth rod lenses 156a from the right are applied to the end. Is not hanging. When viewed in the vertical and horizontal directions, it is understood that the position of the rod lens 156a where the end of the light intensity distribution 138 is hung and the shape and area of the hung region are also changed. (Here, the number of rod lenses is different from the number of rod lenses in the other FIGS. 15 and 16 and the like. However, the number of rod lenses does not matter in explaining the principle. There is no problem to explain.)
For this reason, in the configuration shown in FIG. 2, the nonuniformity of the illuminance due to the end of the light intensity distribution on the surface of the mask 200 which is the illuminated surface is reduced. This is because, in FIG. 15 described above, the positions of the light intensity distributions 12a and 12e are shifted (for example, gradually outward or inward) with respect to the rod lens rows aligned in the direction perpendicular to the paper surface, and thus This corresponds to the fact that the light intensity distributions 52a and 52e are shifted (gradually inward or outward) and the concave portions 53 of the light intensity distribution 50 become smaller. However, as described above, since the shape of the light intensity distribution 10 actually changes with respect to the rod lens array aligned in the direction perpendicular to the plane of the drawing, the positions of the light intensity distributions 52a and 52e are completely displaced. It does not become. In any case, it is understood that the configuration shown in FIG. 2 makes the shape of the effective light source distribution uniform.

  FIG. 12 shows an illuminance distribution on the illumination target surface 200 according to the configuration shown in FIG. FIG. 12 corresponds to FIG. 4 described later. FIG. 12 attaches a color drawing to the present application to facilitate understanding of the present invention. The numbers in FIG. 12A indicate the number of additions of the light intensity distribution of each rod lens 156a. In order to facilitate understanding, the representative number of overlaps is superimposed on the illumination area in FIG. FIG. 12 shows the light intensity distribution on the illumination target surface 200 when the relative shift angle between the fly-eye lenses 130 and 150 is 22.5 degrees.

  FIG. 13 shows the relationship between the relative shift angles of the fly-eye lenses 130 and 150 and the illuminance unevenness in the configuration shown in FIG. When the relative shift angle is 0 degrees as shown in FIG. 16, the illuminance unevenness on the illuminated surface 200 is as high as about 0.37, but when the relative shift angle is 22.5 degrees as shown in FIG. It will be appreciated that the illumination unevenness on the surface 200 has been improved to 0.23. In FIG. 12, when the relative shift angle is not 22.5 degrees but in the range of 18 degrees or more and 30 degrees or less, the illuminance non-uniformity is the same as when the relative shift angle is 22.5 degrees. The relative shift angle is not limited to 22.5 degrees, but may be any number as long as it is 18 degrees or more and 30 degrees or less, since it can be made smaller than the case of 0 degrees. In the case where the shape of the light splitting region (described in FIG. 21) is different from that illustrated, for example, when either one is a regular hexagon or both are regular hexagons, the relative shift angle is 15 degrees. However, if the angle is 12 degrees or more and 20 degrees or less, substantially the same effect can be obtained.

  In FIG. 4, the light intensity distribution on the incident surface 152 of the fly-eye lens 150 or the fly-eye lens 130 is inclined by 22.5 degrees under the conditions of FIG. The simulation result which calculated the illuminance distribution by setting so that it might be non-parallel or asymmetric with the side of 156a is shown. Similarly, FIG. 5 shows that the light intensity distribution on the incident surface 152 of the fly-eye lens 150 or the fly-eye lens 130 is tilted by 15 degrees under the condition of FIG. 18 so that the side of the light intensity distribution on the rod lens 156b becomes the rod lens 156b. 4 shows a simulation result of calculating an illuminance distribution with setting to be non-parallel or asymmetric with the side of. In each case, it will be understood that the non-uniformity of the light intensity distribution remains slightly, but the uniformity is improved as compared with FIGS. 4 and 5 are attached with color drawings to facilitate understanding of the present invention.

  Next, a modified example of the lighting device 100 will be described with reference to FIG. Here, FIG. 6 is a schematic diagram illustrating a simplified optical path of a lighting device 100A as a modification of the lighting device 100. FIG. 7 shows a simplified optical path diagram of an exposure apparatus 1A to which an illumination device 100A is applied instead of the illumination device 100.

  The illumination device 100A is an example of a triple integrator configuration in which a fly-eye lens 170 and a condenser lens 180 are further provided after the condenser lens 160. The cross-sectional shape of the rod lens of the fly-eye lens 170 is set to be rectangular since the shape of the mask 200 surface is typically rectangular. The condenser lens 180 superimposes the light emitted from the fly-eye lens 170 on the surface of the mask 200 to uniformly illuminate the surface of the mask 200. As described above, a masking blade or the like may be arranged between the condenser lens 170 and the mask surface.

  In the optical system of the illumination device 100A, the fly-eye lens 130 prevents the influence on the illuminated surface 200 from occurring even if the light intensity distribution from the light source 110 changes. The shape of the effective light source is made substantially uniform, and the fly-eye lens 170 is for making the illuminance distribution on the mask 200 surface as the surface to be illuminated substantially uniform.

  The light intensity distribution incident on the fly-eye lens 150 and the relationship between the rod lens of the fly-eye lens 130 and the rod lenses 156a and 156b are completely the same as the relationship described with reference to FIG. Omitted.

  In the present embodiment, the light intensity distribution incident on the fly-eye lens 170 and the relationship between the rod lens 156 of the fly-eye lens 150 and the rod lens of the fly-eye lens 170 are also the same as the relationships described with reference to FIG. Similarly, they are non-parallel and asymmetric. By arranging the fly-eye lens 170 in this manner, the uniformity on the mask 200 surface, which is the surface to be illuminated, is further improved. Here, the relationship between the fly-eye lens 150 and the fly-eye lens 170 may be such that the incident light intensity distribution is blurred or a stop is provided as in the conventional case.

  The effect of "blurring" will be described. In FIG. 14, which is an explanatory view of the prior art, it is conceivable to blur the ends 12a and 12e of the light intensity distribution 12. Such means can be realized, for example, by shifting the incident surface 22 of the fly-eye lens 20 from a position conjugate with the incident surface of the rod lens constituting the preceding fly-eye lens. An example other than FIG. 14 is shown in FIG. Here, FIG. 20 is a schematic diagram showing the relationship between the fly-eye lens at the subsequent stage, the light intensity distribution of the incident light whose peripheral portion is blurred, and the light intensity distribution on the surface to be illuminated. As shown in FIG. 20, the incident light 10A having the light intensity distributions 14a to 14e (hereinafter, unless otherwise specified, the reference numeral 14 is a general description thereof) includes the light intensity distributions 14a and 14b, 14d, and 14e. Is gently inclined. When the end of the light intensity distribution 14 of the incident light 10A incident on the fly-eye lens 20 is blurred, the five light intensity distributions 54a to 54e written on the right of the illumination target surface 40 are superimposed. A uniform light intensity distribution 50A is formed on the illuminated surface 40.

  However, if the light intensity distribution of the incident light is blurred on the entrance surface of the fly-eye lens, the amount of Helmholtz-Lagrange increases, resulting in a loss of light amount. The Helmholtz-Lagrange quantity is an angle between the height from the optical axis and the optical axis, and is an amount that does not decrease in the optical system due to what is called Helmholtz-Lagrange law in optics. In the illuminating device, since the size of the illuminated surface and the maximum angle of light rays incident on the illuminated surface are determined, the Helmholtz-Lagrange amount on the illuminated surface is determined. When the distribution is blurred on the entrance surface of the fly-eye lens, the angle from the optical axis does not change and the height from the optical axis increases, so the Helmholtz-Lagrange amount must be increased. become. As described above, the Helmholtz-Lagrange amount is not reduced by the optical system, but does not change or only increases. Therefore, if the Helmholtz-Lagrange amount on the illuminated surface is exceeded, the light beam is obstructed. The light cannot reach the illumination surface, and vignetting occurs in the optical system, resulting in a loss of light amount. That is, blurring can be an effective means for making the light intensity distribution uniform, but it is not a versatile technique because of a large loss of light quantity.

  According to this embodiment, on the incident surface 152 of the fly-eye lens 150, the light intensity distribution is not blurred and there is no vignetting due to the aperture, so that the light use efficiency is high, the effective light source distribution is uniform, and A uniform illuminance distribution can be obtained.

  In the present embodiment (modification), a cylindrical lens may be used instead of the fly-eye lens. Here, when a cylindrical lens is used instead of the fly-eye lens, by combining a plurality of cylindrical lenses whose generatrix directions are orthogonal to each other, a configuration equivalent to that of the fly-eye lens is obtained. Alternatively, the fly-eye lenses 130, 150, and 170 in FIG. 7 are replaced with the above-described combination of the cylindrical lenses. In this case, the cylindrical lenses may be combined as shown in FIG. 21 described above, or a plurality of cylindrical lenses having mutually orthogonal generatrix directions may be combined in a configuration different from that in FIG. Here, when a combination of a plurality of cylindrical lenses is viewed from the optical axis direction, the combination of the cylindrical lenses looks like a lattice as shown in FIG. 21B. Here, each region that appears to be divided is referred to as a light division region. The light dividing area 210 is a part that performs a function corresponding to the rod lens of the fly-eye lens.

  The plurality of sides forming the outline of the light splitting region 210 are made non-parallel between a combination of two cylindrical lenses arranged in place of the fly-eye lenses 130 and 150 in FIG. Non-parallelism is also set between the two sets of cylindrical lenses arranged in place of the lenses 150 and 170. Further, in FIG. 6, the angle formed by the sides forming the contours of the light splitting regions between the two sets of cylindrical lenses arranged in place of the fly-eye lenses 130 and 150 is set to 22.5 degrees. In step 6, the angle formed by the sides forming the contours of the light splitting regions is 22.5 degrees between the two sets of cylindrical lenses arranged in place of the fly-eye lenses 150 and 170. In FIG. 6, between the two sets of cylindrical lenses arranged in place of the fly-eye lenses 130 and 170, the sides of the lattices of the cylindrical lenses are parallel to each other, but needless to say, they are not non-parallel. I do not care.

  Further, with respect to the symmetry axis of the light splitting region of the combination of the cylindrical lenses arranged in place of the fly's eye lens 130 and the straight line parallel thereto, the light splitting region of the combination of the cylindrical lenses arranged in place of the fly's eye lens 150 Is asymmetric and a combination of a cylindrical lens arranged in place of the fly's eye lens 170 with respect to the axis of symmetry of the light splitting region and a straight line parallel to the symmetry axis of the combination of cylindrical lenses arranged in place of the fly's eye lens 150 Has an asymmetric light splitting region. Here, regarding the symmetry axis of the light splitting region and the straight line parallel to the light splitting region of the combination of the cylindrical lenses arranged in place of the fly-eye lens 130, the light splitting of the combination of the cylindrical lenses arranged in place of the fly-eye lens 170 The region is preferably symmetrical, but may of course be asymmetrical.

  Next, a further modification of the lighting device 100 will be described with reference to FIG. Here, FIG. 11 is a schematic diagram illustrating a simplified optical path of a lighting device 100 </ b> B as a modification of the lighting device 100. The illumination device 100B uses an optical pipe (internal reflection member) 190 as a light integrator instead of the fly-eye lens 130, and includes a condensing optical system 120a and a relay optical system 195.

  The condensing optical system 120a condenses a light beam from the light source 110 near the incident surface of the optical pipe 190, and forms a light beam having a predetermined divergence angle into the light beam incident on the optical pipe 120. The condensing optical system 120a includes at least one lens element, but may include a mirror for bending an optical path in some cases. When the optical pipe 190 is made of a glass rod, the focal point of the light collecting optical system 120a is defocused from the incident surface 192 of the optical pipe 190 to the light source side in order to increase the durability of the glass rod. Have been.

  The optical pipe 190 repeats reflection on the side surface of a light beam incident at a predetermined divergence angle from the light condensing point of the light condensing optical system 120a, so that the light intensity distribution that is non-uniform on the incident surface 192 is reflected on the exit surface 194. Make it even. The entrance surface 192 of the optical pipe 190 is arranged at a slightly distance from the focal point. This is because the energy density becomes enormous near the focal point, and there is a possibility that the coating (anti-reflection film) and the glass material on the incident surface of the optical pipe 190 may be damaged.

  In this embodiment, the optical pipe 190 is a hexagonal prism rod that forms a reflection surface with a hexagonal cross-sectional shape and is formed of, for example, glass. However, such a structure is exemplary, and the cross section may be an m-square (m: even number) or a hollow rod. The entrance surface 192 of the optical pipe 190 and the entrance surface 152 of the fly-eye lens 150 are optically conjugated to each other, and the optical pipe 190 has, for example, a rectangular shape and the fly-eye lens 150 is as shown in FIG. Placed in

  The relay optical system 195 forms an image of the exit surface 194 of the optical pipe 190 on the entrance surface 152 of the fly-eye lens 150 at a predetermined magnification, and the two are substantially conjugate with each other. The relay optical system 195 is constituted by a variable magnification zoom lens, and is capable of adjusting a light beam area incident on the fly-eye lens 150. Therefore, a plurality of illumination conditions (that is, coherence factor σ: NA of illumination optical system / NA of projection optical system) can be formed.

  The other configuration is the same as that of the lighting device 100, and thus the detailed description is omitted here. The lighting device 100B can also achieve the same operation as the lighting device 100.

However, in the lighting device 100B, the optical pipe 190 requires a long optical rod in order to improve the uniformity of the effective light source distribution. Thus, the short wavelength light source (e.g., _{F 2} excimer laser with a wavelength of 157 nm) When using the better to use the illumination apparatus 100 or 100A excellent in transmittance preferred.

  The mask 200 is made of, for example, quartz, has a circuit pattern (or image) to be transferred formed thereon, and is supported and driven by a mask stage (not shown). Diffracted light emitted from the mask 200 passes through the projection optical system 300 and is projected onto the plate 400. The plate 400 is an object to be exposed and is coated with a resist. The mask 200 and the plate 400 are arranged in an optically conjugate relationship.

  If the exposure apparatus 1 is a step-and-scan exposure apparatus (that is, a scanner), the pattern of the mask 200 is transferred onto the plate 400 by scanning the mask 200 and the plate 400. If the exposure apparatus 1 is a step-and-repeat exposure apparatus (that is, a stepper), the exposure is performed with the mask 200 and the plate 400 stationary.

  The mask stage (not shown) supports the mask 200 and is connected to a moving mechanism (not shown). The mask stage and the projection optical system 300 are provided, for example, on a stage barrel surface plate supported via a damper or the like on a base frame mounted on a floor or the like. Any configuration known in the art can be applied to the mask stage. A moving mechanism (not shown) is configured by a linear motor or the like, and can move the mask 200 by driving the mask stage in a direction orthogonal to the optical axis. The exposure apparatus 1 scans the mask 200 and the plate 400 in a synchronized state by a control device (not shown).

  The projection optical system 300 forms an image of a light beam having passed through the pattern formed on the mask 200 on a plate 400. The projection optical system 400 includes an optical system including only a plurality of lens elements, a catadioptric optical system including a plurality of lens elements and at least one concave mirror (a catadioptric optical system), a plurality of lens elements and at least one An optical system having a diffractive optical element such as a kinoform, an all-mirror optical system, or the like can be used. When chromatic aberration needs to be corrected, a plurality of lens elements made of glass materials having different dispersion values (Abbe values) from each other may be used, or the diffractive optical element may be configured to cause dispersion in a direction opposite to that of the lens element. I do.

  The plate 400 is a wafer in the present embodiment, but widely includes a liquid crystal substrate and other objects to be processed. Photoresist is applied to the plate 400. The photoresist application step includes a pretreatment, an adhesion improver application process, a photoresist application process, and a pre-bake process. Pretreatment includes washing, drying and the like. The adhesion improver application treatment is a surface modification treatment (that is, a hydrophobic treatment by applying a surfactant) for improving the adhesion between the photoresist and the base, and the organic film such as HMDS (Hexamethyl-disilazane) is applied. Coat or steam. Prebaking is a baking (firing) step, but is softer than that after development, and removes the solvent.

  The plate 400 is supported on a wafer stage (not shown). Since any configuration known in the art can be applied to the wafer stage, a detailed description of its structure and operation is omitted here. For example, the wafer stage moves the plate 400 using a linear motor in a direction orthogonal to the optical axis. For example, the mask 200 and the plate 400 are scanned synchronously, and the positions of the mask stage and the wafer stage are monitored by, for example, a laser interferometer, and both are driven at a constant speed ratio. The wafer stage is provided on a stage base supported on a floor or the like via a damper, for example.

  Hereinafter, the exposure operation of the exposure apparatus 1 will be described. In the exposure, the light beam emitted from the light source 110 is incident on the fly-eye lens 130 after the beam shaping optical system 120 shapes the beam into a desired one. The fly's eye lens 130 uniformly illuminates the fly's eye lens 150 via the condenser lens 140. The light beam that has passed through the fly-eye lens 150 illuminates the surface of the mask 200 via the condenser lens 160. The shape of the effective light source can be made uniform by the positional relationship between the fly-eye lenses 130 and 150.

  When adjusting the positional relationship between the fly-eye lenses 130 and 150, either of them may be rotated. However, for example, in the structure shown in FIG. 6, the cross-sectional shape of the rod lens 156 of the fly-eye lens 150 is normally set to a hexagon, and when a circle is cut out from the hexagon, the fly-eye lens is not affected by the rotation. Preferably, 150 is rotated.

  The light beam that has passed through the mask 200 is reduced and projected on the plate 400 at a predetermined magnification by the image forming action of the projection optical system 300. The angular distribution (ie, the effective light source distribution) of the exposure light beam on the plate 400 becomes substantially uniform. If the exposure apparatus 1 is a stepper, the light source unit and the projection optical system 300 are fixed, and the mask 200 and the plate 400 are synchronously scanned to expose the entire shot. Further, the wafer stage of the plate 400 is stepped to move to the next shot, and a number of shots are transferred onto the plate 400 by exposure. If the exposure apparatus 1 is a scanner, exposure is performed with the mask 200 and the plate 400 stationary.

  In the exposure apparatus 1 of the present invention, the side of the rod lens of the fly-eye lens 130 or the light intensity distribution formed by the fly-eye lens 130 is set to be non-parallel to any side of the rod lens 156, or the symmetry of the rod lens 156 is determined. Since the effective light source distribution is made uniform by setting it asymmetrical with respect to the axis, pattern transfer to the resist is performed with high precision, and high-quality devices (semiconductor devices, LCD devices, imaging devices (such as CCD), thin-film magnetic heads, etc.) ) Can be provided. In addition, since no stop or the like is arranged near the entrance surface 152 of the fly-eye lens 150, loss of light amount and reduction in throughput can be prevented.

  Next, a method for manufacturing a device using the above-described exposure apparatus 1 will be described with reference to FIGS. FIG. 8 is a flowchart for explaining the manufacture of devices (semiconductor chips such as ICs and LSIs, LCDs, CCDs, etc.). Here, the manufacture of a semiconductor chip will be described as an example. In step 1 (circuit design), the circuit of the device is designed. Step 2 (mask fabrication) forms a mask on which the designed circuit pattern is formed. In step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is referred to as a preprocess, and an actual circuit is formed on the wafer by lithography using the mask and the wafer. Step 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer created in step 4, and includes processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). . In step 6 (inspection), inspections such as an operation check test and a durability test of the semiconductor device created in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7).

  FIG. 9 is a detailed flowchart of the wafer process in Step 4. Step 11 (oxidation) oxidizes the wafer's surface. Step 12 (CVD) forms an insulating film on the surface of the wafer. Step 13 (electrode formation) forms electrodes on the wafer by vapor deposition or the like. Step 14 (ion implantation) implants ions into the wafer. In step 15 (resist processing), a photosensitive agent is applied to the wafer.

  Step 16 (exposure) uses the exposure apparatus 1 to expose a circuit pattern on the mask onto the wafer. Step 17 (development) develops the exposed wafer. Step 18 (etching) removes portions other than the developed resist image. Step 19 (resist stripping) removes unnecessary resist after etching.

  By repeating these steps, multiple circuit patterns are formed on the wafer. According to the manufacturing method of the present embodiment, the effective light source distribution can be made uniform, so that a high-quality device can be manufactured as compared with the related art, and the reduction in throughput due to aperture and blurring does not occur. Excellent. As described above, the device manufacturing method using the exposure apparatus 1 and the resulting device also function as one aspect of the present invention.

  The preferred embodiments of the present invention have been described above. However, it goes without saying that the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the invention.

  According to the present embodiment, a substantially uniform distribution can be obtained on the illuminated surface without stopping the aperture on the incident surface of the rod lens and without blurring the distribution on the incident surface of the rod lens. Get. Further, by using the lighting device, an exposure device with high productivity can be obtained.

FIG. 4 is a simplified optical path diagram of the lighting device of the present invention. FIG. 2 is a plan view showing an arrangement relationship between two fly-eye lenses shown in FIG. 1 with respect to two possible shapes of a fly-eye lens at a subsequent stage. It is a top view for explaining a square and a regular hexagon rotation symmetry axis. 2 is an improved illuminance distribution on a surface to be illuminated when the rod lens has a square cross-sectional shape in the illumination device shown in FIG. 1. 2 is an improved illuminance distribution on a surface to be illuminated when the rod lens has a hexagonal cross-sectional shape in the illumination device shown in FIG. 1. FIG. 3 is a simplified optical path diagram of a lighting device as a modification of the lighting device shown in FIG. 1. FIG. 7 is a simplified optical path diagram of an exposure apparatus having the illumination device shown in FIG. 6. 6 is a flowchart for explaining the manufacture of a device (a semiconductor chip such as an IC or an LSI, an LCD, a CCD, or the like). 9 is a detailed flowchart of a wafer process in Step 4 shown in FIG. FIG. 2 is a simplified optical path diagram of an exposure apparatus having the illumination device shown in FIG. 1. FIG. 4 is a simplified optical path diagram of a lighting device as a further modification of the lighting device shown in FIG. 1. FIG. 3 is a schematic plan view of an illuminance distribution on a surface to be illuminated when the configuration shown in FIG. 2 is used. 3 is a graph showing a relationship between a relative shift angle between two fly-eye lenses and illuminance unevenness on a surface to be illuminated when the configuration shown in FIG. 2 is used. It is a top view which shows the relationship between the rod lens of the fly-eye lens of the latter stage of the illumination apparatus which has the conventional two fly-eye lenses, and the light intensity distribution shape of incident light. FIG. 15 is a schematic cross-sectional view illustrating a light intensity distribution formed on a surface to be illuminated by a fly-eye lens that has received the incident light illustrated in FIG. 14. FIG. 16 is a schematic diagram illustrating the light intensity distribution of the illuminated surface illustrated in FIG. 15 in a plan view. 9 is an illuminance distribution on a surface to be illuminated when a rod lens of a fly-eye lens at a subsequent stage in a conventional illumination device has a square cross-sectional shape. 9 is an illuminance distribution on a surface to be illuminated in a case where a rod lens of a fly-eye lens in a subsequent stage in a conventional illumination device has a hexagonal cross-sectional shape. FIG. 16 is a schematic plan view of a stop and a stop for improving uneven illuminance distribution on the surface to be illuminated shown in FIG. 15. It is a schematic diagram which shows the relationship between the light intensity distribution of the incident light whose peripheral part is blurred, and the light intensity distribution of the surface to be illuminated. FIG. 2 is a schematic diagram illustrating an arrangement of a plurality of cylindrical lenses.

Explanation of reference numerals

1 Exposure Device 100 Illumination Device 130 Fly Eye Lens 150 Fly Eye Lens 170 Fly Eye Lens 200 Mask 300 Projection Optical System 400 Plate

Claims (6)

In an illumination optical system that illuminates a surface to be irradiated with a substantially incoherent light flux from the light source unit,
A first light integrator configured of a first optical element having a cross section perpendicular to the optical axis formed by the plurality of first sides, for uniformly illuminating a surface to be illuminated;
A second light integrator for uniformly illuminating the first light integrator with a substantially incoherent light beam from the light source unit,
The illumination optical system according to claim 1, wherein an outline of an illumination range on an incident surface of said first light integrator is composed of a plurality of second sides each of which is not parallel to any of said first sides. In an illumination optical system that illuminates a surface to be irradiated with a substantially incoherent light flux from the light source unit,
A first light integrator configured of a first optical element having a cross section perpendicular to the optical axis formed by the plurality of first sides, for uniformly illuminating a surface to be illuminated;
A second optical element in which a cross section perpendicular to the optical axis is formed by a plurality of second sides that are not parallel to any of the first sides; An illumination optical system, comprising: a second light integrator for uniformly illuminating the first light integrator with a coherent light beam. In an illumination optical system that illuminates a surface to be irradiated with a substantially incoherent light flux from the light source unit,
A first light integrator having a plurality of first symmetry axes and having a first cross-sectional shape perpendicular to the optical axis and having a first cross-sectional shape, for uniformly illuminating a surface to be illuminated;
A second light integrator for uniformly illuminating the first light integrator with a substantially incoherent light beam from the light source unit,
The illumination optical system according to claim 1, wherein an illumination range of an incident surface of the first light integrator is asymmetric with respect to any of the first symmetry axes. In an illumination optical system that illuminates a surface to be irradiated with a substantially incoherent light flux from the light source unit,
A first light integrator configured of a first optical element having a plurality of first symmetry axes and having a first cross-sectional shape perpendicular to the optical axis, for uniformly illuminating a surface to be illuminated;
A second optical element having a second cross-sectional shape perpendicular to the optical axis so as to be asymmetric with respect to any of the first symmetry axes, and a substantially incoherent light flux from the light source unit; An illumination optical system comprising: a second light integrator for uniformly illuminating the first light integrator. An illumination optical system according to any one of claims 1 to 4,
An exposure apparatus comprising: a projection optical system that projects a reticle pattern illuminated by the illumination optical system onto an object to be exposed. A device manufacturing method, comprising: exposing an object to be exposed using the exposure apparatus according to claim 5; and developing the exposed object.