JP2009130071A - Illumination optical system, exposure apparatus, and method of manufacturing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illumination optical system achieving high-grade resolution with a simple configuration, and to provide an exposure apparatus. <P>SOLUTION: In the illumination optical system that is used for the exposure apparatus for exposing a pattern on a precursor to a substrate using light from a light source, irradiates the precursor with light, and has a section for adjusting the amount of exposure, the section for adjusting the amount of exposure has a pair of optical element groups capable of varying the interval among the groups while each group includes one optical element or more, and an aperture diaphragm arranged at the side of the precursor as compared with the pair of optical element groups in the optical path of the illumination optical system. In the illumination optical system, the luminous flux diameter of light through the pair of optical element groups is changed since the interval of the pair of optical element groups changes, and spread in the aperture diaphragm of rays emitted from a point at a finite or infinite distance is changed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an illumination optical system, an exposure apparatus, and a device manufacturing method.

  Projection exposure apparatuses that expose an original (reticle or mask) pattern onto a substrate such as a wafer using a projection optical system have been used in the past, and there is an increasing demand for improvement in economy and high-quality resolution. In order to improve economy, it is necessary to suppress an increase in cost due to an increase in the size of the exposure apparatus. In addition, when the exposure amount varies, the fidelity of the pattern decreases and the CD uniformity deteriorates when the photosensitive substrate is exposed. It is also necessary to change the exposure amount according to the shape of the polarized illumination or the pattern of the original. Thus, high-precision exposure control is required for high-quality resolution.

Conventionally, it is known that the exposure amount is discretely adjusted using the switchable ND filter disclosed in Patent Document 1 or the mesh filter disclosed in Patent Document 2. Further, Patent Document 3 discloses a method for continuously adjusting the exposure amount by enlarging / reducing the beam diameter of the laser light using a zoom expander and an aperture.
JP-A 61-202437 JP-A-63-331630 Japanese Unexamined Patent Publication No. 63-213927

  However, Patent Documents 1 and 2 have low accuracy because the exposure amount is discretely controlled. Highly accurate exposure control requires continuous control of exposure. On the other hand, the zoom expander of Patent Document 3 has a simplified configuration in FIG. 2 of the same document, but in reality, since aberration correction is required over the zoom range, many lenses and zoom groups are required. This increases the size and cost of the exposure apparatus.

  The present invention relates to an illumination optical system and an exposure apparatus that enable high-quality resolution with a simple configuration.

  An illumination optical system according to an aspect of the present invention is used in an exposure apparatus that exposes a pattern of an original on a substrate using light from a light source, and illuminates the original and includes an exposure amount adjustment unit. The exposure amount adjusting unit includes a pair of optical element groups, each group including one or more optical elements, and a distance between the groups being variable, and an optical path of the illumination optical system, than the pair of optical element groups. An aperture stop disposed on the original plate side, and a light flux diameter of the light passing through the pair of optical element groups is changed by changing a distance between the pair of optical element groups, and is finite or infinite The spread at the aperture stop of a light beam emitted from a distant point changes.

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

  According to the present invention, it is possible to provide an illumination optical system and an exposure apparatus that enable high-quality resolution with a simple configuration.

  Hereinafter, an exposure apparatus 100 according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 2 is a schematic block diagram of the exposure apparatus 100. The exposure apparatus 100 is a projection exposure apparatus that exposes a pattern of a reticle (original) 13 onto a wafer (substrate) 16 by a step-and-can method. However, the exposure apparatus 100 can also apply a step-and-repeat method. The exposure apparatus 100 includes a light source 1, an illumination optical system 110, a reticle stage 14, a projection optical system 15, and a wafer stage 17.

  The light source 1 emits light that exposes the pattern of the reticle 13 onto the wafer 16. The light source 1 is, for example, an ArF laser having a wavelength of about 193 nm or a KrF laser having a wavelength of about 248 nm, but the present invention does not limit the type, wavelength, or number of light sources. For example, the light source 1 is not limited to a laser, and may be a non-laser light source such as a mercury lamp.

  The illumination optical system 110 includes a beam routing optical system 2, an exposure amount adjustment unit 3, a beam shaping optical system 4, an optical integrator 5, a light shielding member 6, condenser optical systems 7, 10, 12, a light reduction member 8, and a traveling field stop 9. And a mirror 11.

  The beam routing optical system 2 condenses the light beam from the light source 1 to enlarge and reduce the beam, and guides the light beam to the exposure adjustment unit 3. Therefore, the beam routing optical system 2 may be constituted by a known beam expander. Thus, in this embodiment, the exposure adjustment unit 3 is provided in addition to the beam routing optical system 2.

  The exposure amount adjusting unit 3 has a function of adjusting the light amount of the emitted light beam (that is, the exposure amount). The exposure adjustment operation by the exposure adjustment unit 3 is controlled by the control unit 40. The exposure amount adjusting unit 3 will be described later.

  The beam shaping optical system 4 includes a plurality of optical elements, a zoom optical system, and the like. The beam shaping optical system 4 adjusts the intensity distribution and angular distribution of the light beam incident on the optical integrator 5 at the subsequent stage.

  The optical integrator 5 is, for example, a microlens array in which a plurality of refractive optical elements, reflective optical elements, and diffractive optical elements such as Fresnel lenses are two-dimensionally arranged. Moreover, the optical integrator 5 may be a computer generated hologram (CGH: Computer Generated Hologram). The light beam emitted from the optical integrator 5 is condensed by the condenser optical system 7 and illuminates the surface on which the traveling field stop 9 is positioned in a superimposed manner.

  The light shielding member 6 is disposed in the vicinity of the exit surface of the optical integrator 5. The surface on which the light shielding member 6 is located has a conjugate relationship with the pupil surface 15a of the projection optical system 15. Various modified illuminations can be formed according to the shape of the light shielding member 6. An example of a specific switching mechanism of the light shielding member 6 will be described with reference to FIG. The light shielding member 6 includes a plurality of differently shaped apertures 601 to 603 disposed on a circular substrate 600. The substrate 600 is configured to be rotatable around the point O so that one of the diaphragms 601 to 603 on the substrate 600 is located in the optical path. The diaphragm 601 is a normal aperture diaphragm. A diaphragm 602 is a diaphragm for dipole illumination, and dipole illumination can be formed by cutting out a light beam from conventional illumination, annular illumination, or the like. The stop 603 is a stop for a quadrupole, and a quadrupole illumination can be formed by cutting out a light beam from conventional illumination, annular illumination, or the like.

  The dimming member 8 is, for example, a density filter or a metal blade. By controlling the movement or rotation of the light reducing member 8, the light intensity distribution reaching the irradiated surface can be adjusted.

  The traveling field stop 9 is disposed at a position conjugate with the irradiated surface on which the reticle (original) 13 is located. The traveling field stop 9 is composed of a plurality of movable light-shielding plates, and controls the illumination range of the irradiated surface by controlling to an arbitrary opening shape.

  The light beam that has passed through the traveling field stop 9 is guided to the irradiated surface by the condenser optical system 10, the (bending) mirror 11, and the condenser optical system 12.

  The reticle 13 is supported and driven by a reticle stage 14. The pattern of the reticle 13 disposed on the irradiated surface is projected onto the wafer 16 positioned on the exposure surface by the projection optical system 15. The wafer stage 17 holds the wafer 16 and is moved in a three-dimensional direction. The movement of the reticle stage 14 and the wafer stage 17 is controlled by the control unit 40. The reticle 13 and the wafer 16 are subjected to scanning exposure in synchronization with the arrow direction in FIG. When the reduction magnification of the projection optical system is 1 / β, when the scanning speed of the wafer stage 17 is V, the scanning speed of the reticle stage 14 is βV.

  In this embodiment, the wafer 16 is used. However, the present invention does not limit the type of the substrate to be exposed, and widely includes a liquid crystal substrate and other substrates. A resist is applied to the substrate.

  The control unit 40 controls the operation of each unit of the exposure apparatus 100. For example, detection results by a laser interferometer (not shown) that measures the positions of the reticle stage 14 and the wafer stage 17 are acquired, and the operation of these stages is controlled. Further, the control unit 40 controls the movement operation of the optical element group by a moving unit (to be described later) of the exposure amount adjustment unit 3 based on the detection results of the exposure amount detection units 50a and 50b.

  The exposure amount detection unit 50 a is configured to be detachable from the reticle stage 14, between the condenser optical system 12 and the reticle 13, or between the reticle 13 and the projection optical system 15. Similarly, the exposure amount detection unit 50 b is arranged on the wafer stage 17 or configured to be detachable between the projection optical system 15 and the wafer 16. Alternatively, the exposure amount detection unit may receive a part of the light beam reflected by the beam splitter by disposing a beam splitter (not shown) in the illumination optical system 110. The exposure amount detection units 50a and 50b are illuminance meters (integrated exposure amount detection units) that detect the amount of light during exposure. The exposure amount detection units 50a and 50b are arranged at a position where the reticle 13 and the wafer 16 are arranged, or at a position optically conjugate with the position, and transmit a signal corresponding to the detection result to the control unit 40.

  The illumination optical system 110 uses the light L emitted from the light source 1 to Koehler illuminate the reticle 13. The light reflecting the reticle pattern is projected onto the wafer 16 via the projection optical system 15. When the illumination conditions such as the apertures 601 to 603 are changed, or when there is a variation in the pattern shape and the exposure amount over time, the control unit 40 controls the exposure amount adjustment unit based on the detection results of the exposure amount detection units 50a and 50b. 3 exposure amount adjustment operation is controlled. That is, the control unit 40 controls the exposure amount adjusted by the exposure amount adjustment unit 3.

  Hereinafter, the configuration of the illumination optical system 110 according to the first embodiment will be described in detail with reference to FIG. The exposure amount adjustment unit 3 of the illumination optical system 110 includes an optical integrator 301, a beam diameter adjustment optical system 302, and an aperture stop 303.

  The optical integrator (first optical integrator) 301 defines an emission angle of a light beam, and the incident light beam is emitted at a constant divergence angle. The optical integrator 301 is a fly-eye lens in which a wavefront of incident light is divided to form a plurality of light sources at or near the light exit surface, and in this embodiment, a large number of rectangular microlenses are arranged. The fly-eye lens emits after converting the angular distribution of incident light into a position distribution, and the incident surface 301a and the exit surface 301b are in a Fourier transform relationship. Thereby, the vicinity of the emission surface 301b of the optical integrator 301 is a secondary light source. Due to the uniformizing effect of the optical integrator 301, there is an advantage that the adjustment of the exposure amount is stabilized.

  However, the optical integrator 301 is not limited to a fly-eye lens. For example, the optical integrator 301 may be an optical rod, a fiber bundle, a CGH, a diffractive optical element, a plurality of sets of cylindrical lens array plates arranged so that each set is orthogonal, and a reflective integrator with coating.

  FIG. 1 shows a ray emitted from the optical integrator 301 in parallel with the optical axis OA as a solid line, a ray emitted upward in FIG. 1 as a broken line, and a ray emitted downward in FIG. Omitted. The emitted light beam enters the beam diameter adjusting optical system 302.

  The beam diameter adjusting optical system 302 includes a pair of optical element groups 30a and 30b and moving portions 35a and 35b, and changes the light beam diameter of light that has passed through the pair of optical element groups 30a and 30b.

  Each of the pair of optical element groups 30a and 30b has one or more optical elements, and constitutes a condenser optical system (condensing optical system) in this embodiment. The optical element group 30a includes a convex lens 302a in this embodiment. In this embodiment, the optical element group 30b includes a concave lens 302b and a convex lens 302c. Thus, the pair of optical element groups 30a and 30b in the present embodiment is a condenser optical system (condensing optical system). However, in the present invention, the pair of optical element groups 30a and 30b is not limited to such a configuration, and may include a mirror instead of a lens.

  For example, as shown in FIG. 1C, the optical element group 30a may be replaced with an optical element group 30Aa having a convex lens 302a and a concave lens 302d in order from the light source 1 along the optical path. The optical element group 30Aa has one concave lens 302d at the rear stage (reticle 13 side) of the convex lens 302a, but the number of concave lenses arranged on the reticle 13 side of the convex lens 302a is not limited.

  Similarly, as shown in FIG. 1C, the optical element group 30b may be replaced with an optical element group 30Ab having a concave lens 302e, a concave lens 302b, and a convex lens 302c in order along the optical path from the light source side. The optical element group 30Ab has one concave lens 302e on the light source 1 side of the concave lens 302b, but the number of concave lenses arranged on the light source 1 side of the concave lens 302e is not limited.

  The moving unit 35a moves the optical element group 30a in the optical axis direction D. The moving unit 35b moves the optical element group 30b in the optical axis direction D. However, as long as the distance between the optical element groups 30a and 30b is changed, only one of the moving parts 35a and 35b is required. As a result, the moving unit moves at least one of the pair of optical element groups 30a and 30b to change the interval between the pair of optical element groups 30a and 30b. As a result, the beam diameter of the light passing through the beam diameter adjusting optical system 302 is changed.

  The movement of the pair of optical element groups 30a and 30b by the moving units 35a and 35b is controlled by the control unit 40. The control unit 40 controls the movement amount of the optical element group by the movement units 35a and / or 35b based on the detection result of the exposure amount detection unit 50a and / or 50b.

  The pair of optical element groups 30a and 30b is configured as a zoom optical system (variable magnification optical system) having a variable focal length by the moving units 35a and 35b.

  The aperture stop 303 defines an effective area of the light beam in order to adjust the exposure amount. The aperture stop 303 has a light shielding part 303a and an opening 303b. The optical axis OA passes through the center of the opening 303b. The aperture stop 303 has an entrance surface 303c and an exit surface 303d. In this embodiment, the aperture stop 303 has a fixed area of the aperture 303b, but may be an iris diaphragm or a blade having a variable aperture area. The aperture stop 303 is disposed closer to the original (on the irradiated surface side) along the optical path than the pair of optical element groups 30a and 30b.

  When the moving parts 35a and 35b move at least one of the pair of optical element groups 30a and 30b, the light beam diameter on the incident surface 303c of the aperture stop 303 of the light that has passed through the beam diameter adjusting optical system 302 is changed.

  FIG. 1A is a schematic cross-sectional view showing a state where the exit beam diameter (light beam diameter) of the beam diameter adjusting optical system 302 is minimized. In FIG. 1B, the optical element group 30a is fixed and the optical element group 30b is moved to the aperture stop 303 side along the optical axis direction D, thereby extending the focal length of the beam diameter adjusting optical system 302 and emitting the light. It is a schematic sectional drawing which shows the state which expanded the beam diameter. FIG. 4A is a graph showing the light intensity distribution of the light beam passing through the aperture stop 303 in a state where the exit beam diameter of the beam diameter adjusting optical system 302 is minimized as shown in FIG. . FIG. 4B is a graph showing the light intensity distribution of the light beam passing through the aperture stop 303 in a state where the focal length of the beam diameter adjusting optical system 302 is extended and the exit beam diameter is enlarged as shown in FIG. It is.

  FIG. 1A shows a position where the light beam diameter is minimum on the aperture stop 303 within a range in which the moving portions 35a and / or 35b move at least one of the pair of optical element groups 30a and 30b. As shown in FIG. 1A, the position at which the beam diameter is minimum is preferably the condensing position (focal position) of the optical element group 30b. This is because the beam diameter is minimized at this position. As a result, the exit surface 301b of the optical integrator 301 and the aperture stop 303 are optically arranged in a Fourier transform relationship. However, the present invention does not require a complete Fourier transform relationship.

  As shown in FIGS. 1A and 4A, when the exit beam diameter by the beam diameter adjusting optical system 302 is the minimum, the light shielding by the aperture stop 303 needs to be set to the minimum. Since the exposure amount is maximized at this time, it is possible to prevent a decrease in the exposure amount and suppress a decrease in the throughput. Further, when the beam diameter is enlarged by the beam diameter adjusting optical system 302, the ratio of the amount of light shielded by the aperture stop 303 is increased, and the exposure amount adjustment range can be enlarged.

  For this reason, at this time, the aperture 303b of the aperture stop 303 has a size and a shape that do not block (that is, pass through) the light beam whose emission beam diameter is minimized by the beam diameter adjusting optical system 302.

  Furthermore, for the same reason, when the beam diameter adjusted by the beam diameter adjusting optical system 302 is minimized, the light beam emitted from a point at a finite or infinite distance spreads on the entrance surface 303c of the aperture stop 303 (hereinafter referred to as “light beam”). "Expansion" is set to be minimal. This beam spread is often used as one of the methods for quantitatively evaluating the aberration of the optical system. When there is such a light beam spread, there is a possibility that the light is blocked by the light blocking portion 303a of the aperture stop 303 beyond the opening 303b. When the exit beam diameter is minimized, it can be prevented by minimizing the beam spread.

  Further, in this embodiment, as shown in FIGS. 1B and 4B, the beam spread increases when the beam diameter is enlarged. In other words, the light beam emitted from a point at a finite or infinite distance changes in the light beam diameter of the light passing through the pair of optical element groups 30a and 30b by changing the distance between the pair of optical element groups 30a and 30b. The spread at the aperture stop 303 changes. When the light beam spread is large, the light intensity distribution at the aperture stop 303 has a trapezoidal shape as shown in FIG. When the light intensity distribution has a trapezoidal shape, the ratio of the amount of light included in the effective area becomes smaller. For this reason, when the beam diameter is enlarged, more light is shielded by the light shielding portion 303a of the aperture stop 303, so that the exposure amount adjustment range becomes large. In this way, the exposure adjustment range can be increased by increasing the beam spread when the beam diameter is expanded, rather than the beam spread when the beam diameter is reduced (minimum) by the beam diameter adjusting optical system 302.

  As a result, the amount of change in the focal length when the beam diameter is enlarged or reduced can be reduced, and the movement distance of the pair of optical element groups 30a and 30b can be reduced to reduce the exposure amount adjustment unit 3.

  Further, since it is only necessary to suppress the beam spread only when the beam diameter is the minimum, design constraints are reduced, and the number of lenses and the number of lens groups can be minimized. For this reason, the beam diameter adjusting optical system 302 can be reduced in size with a simple configuration, and cost increase can be suppressed.

  As described above, according to the illumination optical system 110 of the first embodiment, the exposure amount can be continuously adjusted over a wide range with a simple and small configuration in which the number of lenses and the lens group are minimized. In addition, since the structure of the beam diameter adjusting optical system 302 (exposure amount adjusting unit 3) is simplified and miniaturized, the economic efficiency of the exposure apparatus 100 is excellent.

  Hereinafter, the exposure amount adjustment unit 3A of the illumination optical system 110 according to the second embodiment will be described with reference to FIGS. 5 (a) and 5 (b). The exposure adjustment unit 3 </ b> A includes optical integrators 301 and 313, a beam diameter adjustment optical system 302, an aperture stop 303, a turret 311, and a neutral density filter 312. FIG. 5A corresponds to FIG. 1A and is a schematic cross-sectional view showing a state where the beam diameter is minimized. FIG. 5B corresponds to FIG. 1B and the beam diameter is enlarged. It is a schematic sectional drawing which shows a state. 5A and 5B, the same reference numerals as those in FIGS. 1A and 1B are the same as those in the first embodiment.

  A neutral density filter 312 serving as a neutral density unit reduces the amount of light when light passes and is provided on the light source side of the optical integrator 301. The neutral density filter 312 is, for example, a filter whose transmittance is controlled by coating a dielectric multilayer film on a glass substrate. In another embodiment, the neutral density filter 312 may be a filter obtained by coating a glass substrate with a light absorbing material such as chromium. In this case, the transmittance can be controlled by changing the concentration of the light-absorbing substance. In yet another embodiment, the neutral density filter 312 may be a filter provided with a mesh-shaped light shielding portion.

  A plurality of neutral density filters 312 are arranged on the turret 311 so that the neutral density filters 312 that can be introduced into the optical path can be switched. Thereby, the exposure amount can be adjusted discretely. By making the difference in transmittance between the plurality of neutral density filters 312 smaller than the exposure amount adjustment range by the beam diameter adjusting optical system 302, the exposure amount can be continuously adjusted over a wide range.

  The optical integrator (second optical integrator) 313 is disposed behind the aperture stop 303, but this order may be reversed. In other words, it is sufficient that the optical integrator 313 is provided adjacent to the aperture stop 303. The optical integrator 313 has the same structure as that of the optical integrator 303. When the beam diameter adjusting optical system 302 enlarges / reduces the beam diameter, it affects the NA and telecentricity of the light beam passing through the aperture stop 303. By disposing the optical integrator 313 behind the beam diameter adjusting optical system 302, a stable beam can be supplied to the beam shaping optical system 4. Further, as shown in FIG. 4B, the beam supplied to the beam shaping optical system 4 is further stabilized when the light intensity distribution in the effective region is made uniform even when the beam diameter is expanded. This is because if the light beam emitted from the exposure adjustment unit 3 is constant regardless of the exposure adjustment, the beam profile shaped by the beam shaping optical system 4 disposed behind becomes stable.

  As described above, according to the exposure amount adjustment unit 3 of the illumination optical system 110 according to the first embodiment, the exposure amount can be continuously adjusted over a wide range with a simple and small configuration in which the number of lenses and the lens group are minimized. be able to.

  As described above, according to the exposure amount adjusting unit 3A of the illumination optical system 110 according to the second embodiment, the exposure amount can be continuously and widely adjusted with a simple and small configuration with the number of lenses and the lens group being minimized. can do.

  Hereinafter, the exposure amount adjusting unit 3B of the illumination optical system 110 according to the third embodiment will be described with reference to FIGS. 6A and 6B. The exposure amount adjustment unit 3B includes a beam diameter adjustment optical system 321 and an aperture stop 303. FIG. 6A corresponds to FIG. 1A and is a schematic sectional view showing a state where the beam diameter is minimized. FIG. 6B corresponds to FIG. 1B and the beam diameter is enlarged. It is a schematic sectional drawing which shows a state.

  The beam diameter adjusting optical system 321 includes a pair of optical element groups 30Ba and 30Bb and moving parts 35a and 35b, and changes the light beam diameter of the light that has passed through the pair of optical element groups 30Ba and 30Bb. Similar to the first embodiment, the moving units 35a and 35b only need to move at least one of the optical element groups 30Ba and 30Bb and change the interval therebetween.

  Each of the pair of optical element groups 30Ba and 30Bb has one or more optical elements. The optical element group 30Ba has a convex lens 321a in this embodiment. In this embodiment, the optical element group 30Bb includes a convex lens 321b and a concave lens 321c. As described above, the pair of optical element groups 30Ba and 30Bb in this embodiment constitute an afocal optical system, and the beam diameter adjusting optical system 321 is an imaging optical system having a variable magnification. Note that the present invention does not limit the number of lenses of the beam diameter adjusting optical system 321. The exposure amount adjusting unit 3 of this embodiment is particularly suitable when the light source 1 is a lamp having a relatively large emission NA.

  FIG. 6 shows a light beam incident on the beam diameter adjusting optical system 321 in parallel with the optical axis OA by a solid line, and a light beam incident upward in FIG. 6 by a broken line. Incident light rays are omitted.

  The effect of adjusting the exposure amount can be understood from FIG. In the exposure adjustment unit 3B, as shown in FIG. 4A, the light beam spread becomes larger when the beam diameter is expanded as shown in FIG. 4B than when the beam diameter is minimum. As shown in FIG. 4B, the ratio of the amount of light contained in the effective region is smaller when the light beam spread is larger and the light intensity distribution is trapezoidal. For this reason, when the beam diameter is expanded, more light is shielded by the aperture stop 303, so that the exposure amount adjustment range becomes large.

  As described above, according to the exposure amount adjustment unit 3B of the illumination optical system 110 according to the third embodiment, the exposure amount can be continuously and widely adjusted with a simple and small configuration with the number of lenses and the lens group being minimized. can do.

  Next, an embodiment of a device manufacturing method using the exposure apparatus 100 will be described with reference to FIGS. FIG. 7 is a flowchart for explaining how to fabricate devices (ie, semiconductor chips such as IC and LSI, LCDs, CCDs, etc.). Here, the manufacture of a semiconductor chip will be described as an example. In step 1 (circuit design), a device circuit is designed. In step 2 (reticle fabrication), a reticle on which the designed circuit pattern is formed is fabricated. In step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by the lithography technique of the present invention using the reticle and the wafer. Step 5 (assembly) is called a post-process, and is a process for 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). Including. In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device created in step 5 are performed. Through these steps, the semiconductor device is completed and shipped (step 7).

  FIG. 8 is a detailed flowchart of the wafer process in Step 4. In step 11 (oxidation), the surface of the wafer is oxidized. In step 12 (CVD), an insulating film is formed on the surface of the wafer. In step 13 (electrode formation), an electrode is formed on the wafer by vapor deposition or the like. In step 14 (ion implantation), ions are implanted into the wafer. In step 15 (resist process), a photosensitive agent is applied to the wafer. Step 16 (exposure) uses the exposure apparatus 100 to expose the pattern of the reticle 13 onto the wafer 16. In step 17 (development), the exposed wafer 16 is developed. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), the resist that has become unnecessary after the etching is removed. By repeatedly performing these steps, multiple circuit patterns are formed on the wafer. According to this device manufacturing method, it is possible to manufacture a higher quality device than before by adjusting the exposure amount with high accuracy. Thus, the device manufacturing method using the exposure apparatus and the resulting device also constitute one aspect of the present invention.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist.

It is a schematic block diagram of the exposure amount adjustment part by Example 1 of this invention. It is a schematic block diagram of the exposure apparatus containing the exposure amount adjustment part shown in FIG. It is a schematic plan view for demonstrating switching of the light shielding member of the exposure apparatus shown in FIG. It is the schematic for demonstrating adjustment of the exposure amount by the exposure amount adjustment part shown in FIG. It is the schematic of the exposure amount adjustment part by Example 2 of this invention. It is the schematic of the exposure amount adjustment part by Example 3 of this invention. It is a flowchart for demonstrating manufacture of devices (semiconductor chips, such as IC and LSI, LCD, CCD, etc.). 8 is a detailed flowchart of the wafer process in Step 4 shown in FIG. 7.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 3 Exposure amount adjustment part 13 Reticle (original)
15 Projection optical system 16 Wafer (substrate)
301 Optical Integrator 302 Beam Diameter Adjustment Optical System 302a-302c A Pair of Optical Element Groups 303 Aperture Stop 311 Turret 312 Neutral Filter 313 Optical Integrator 321 Beam Diameter Adjustment Optical System

Claims (11)

In an illumination optical system that is used in an exposure apparatus that exposes a pattern of an original on a substrate using light from a light source, illuminates the original and has an exposure amount adjustment unit,
The exposure amount adjustment unit
Each group includes one or more optical elements, and a pair of optical element groups each having a variable interval,
In the optical path of the illumination optical system, an aperture stop disposed on the original plate side with respect to the pair of optical element groups, and
As the distance between the pair of optical elements changes, the beam diameter of the light that has passed through the pair of optical elements changes, and the light beam emitted from a point at a finite or infinite distance in the aperture stop An illumination optical system characterized in that the spread changes.   2. The illumination according to claim 1, wherein when the light beam diameter is minimum at the position of the aperture stop, the spread of the light beam emitted from a point at a finite or infinite distance is minimum in the aperture stop. Optical system.   3. The illumination optical system according to claim 1, wherein the optical element group on the light source side of the pair of optical element groups includes a convex lens and one or more concave lenses in order from the light source side. .   4. The optical element group on the original plate side of the pair of optical element groups includes one or more concave lenses and a convex lens in order from the light source side. 5. The illumination optical system described in 1.   The pair of optical element groups is a condenser optical system having a variable focal length, and the light is condensed only on an aperture of the aperture stop by the pair of optical element groups. The illumination optical system according to any one of the above. The pair of optical element groups is a condenser optical system having a variable focal length,
6. The illumination optical system according to claim 1, wherein the exposure amount adjusting unit further includes a first optical integrator on the light source side of the pair of optical element groups.   The illumination optical system according to claim 6, wherein the exposure adjustment unit further includes a second optical integrator adjacent to the aperture stop.   The illumination optical system according to claim 1, wherein the exposure amount adjustment unit further includes a light reduction unit that reduces the amount of light.   The illumination optical system according to claim 1, wherein the pair of optical elements includes an afocal optical system. The illumination optical system according to any one of claims 1 to 9, which illuminates an original plate;
An exposure apparatus comprising: a projection optical system that projects an image of the original pattern onto a substrate. Exposing the substrate using the exposure apparatus according to claim 10;
And developing the exposed substrate. A device manufacturing method comprising the steps of: