JPH11162837A - Illumination device and projection aligner using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformarize the distribution of illuminance on a plane to be irradiated by illuminating the plane with a plurality of light fluxes through a light flux mixing means formed of a plurality of optical pipe that mixes a plurality of light fluxes diverging at a constant angle from light flux split elements and emits them at an angle in accordance with the divergence angle. SOLUTION: A beam expander 11 converts the diameter of a light flux emitted from a laser light source 1 to a desired shape. An exit angle keeping optical element 2 emits an incident light flux at a constant exit angle. A converging optical system 3 converges the light flux from the element 2 and leads it to a lens array (light flux split element) 12. The lens array 12 is provided with a plurality of micro lenses arranged in two-dimensional state, and a plurality of secondary light source are formed on its outgoing surface. A light flux mixing means 4 is formed by combining in parallel a plurality of short optical pipes, and it mixes a light flux from the lens array 12 and forms a uniform distribution of illuminance on its exit surface. A zooming optical system 5 projects and forms an image at various scale factors on an incident surfaces 7a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination apparatus and a projection exposure apparatus using the same, for example, an IC, an LSI, and a CC.
D, a so-called stepper, which is an apparatus for manufacturing various devices such as a liquid crystal panel and a magnetic head, is an original plate such as a photomask or a reticle uniformly illuminated with exposure light in a vacuum ultraviolet region from an illumination device (hereinafter referred to as a “reticle”). This is suitable when a device is manufactured by projecting and transferring the above circuit pattern onto a wafer surface coated with a photosensitive agent.

[0002]

2. Description of the Related Art In a projection exposure apparatus for manufacturing a semiconductor device, a reticle on which an electronic circuit pattern is formed is irradiated with a light beam from an illumination system, and the pattern is projected and exposed on a wafer surface by a projection optical system. At this time, one of the requirements for achieving a high resolution is to uniformly irradiate the wafer surface.

[0003] In an illumination device used in this type of projection exposure apparatus, various methods for uniformly irradiating an irradiation surface (reticle surface or wafer surface) have conventionally been adopted. For example, in a projection exposure apparatus called a stepper, an irradiation surface is uniformly illuminated using an illumination system in which a collimator lens and an optical integrator in which a plurality of microlenses are arranged at a predetermined pitch.

[0004] By using such an optical integrator in a lighting device, a plurality of secondary light sources corresponding to the number of microlenses are formed, and the illuminated surface is irradiated in a plurality of directions with a light beam from the secondary light source. And illuminate with overlapping
The illuminance distribution is made uniform.

An illumination device in which the uniformity of the illuminance distribution is improved by using an internal reflection type integrator and an amplitude division type integrator is disclosed in, for example, Japanese Patent Application Laid-Open No. 64-193.
And JP-A-1-295216 and JP-A-1-295216.
It has been proposed in, for example, Japanese Patent Application Laid-Open No. 71718 and Japanese Patent Application Laid-Open No. 2-48627.

FIG. 10 shows that the present applicant has previously filed Japanese Patent Application No. 9-696.
71 is a partial schematic diagram of a lighting device using each of the internal reflection type and amplitude division type integrators proposed in No. 71. FIG.

In FIG. 1, a laser beam emitted from a laser light source 101 is once converged by a lens system 107 slightly before a light incident surface of a light pipe 110 which is an internal reflection type integrator, and then diverges to the light pipe 110. Incident on the inner reflection surface at a predetermined divergence angle.

The divergent laser light incident on the light pipe 110 propagates while being reflected on the inner surface of the light pipe 110. Therefore, the light pipe 110 has a plane perpendicular to the optical axis, for example, a plane 1
13, a plurality of virtual images related to the laser light source 101 are formed.

On the light exit surface 110 ′ of the light pipe 110,
A plurality of virtual images, that is, a plurality of laser beams that appear as if emitted from a plurality of apparent light sources are superimposed. Accordingly, a surface light source having a uniform intensity distribution is formed on the light exit surface 110 'of the light pipe 110.

The condenser lens 105 and the aperture stop 111
The light exit surface 110 ′ of the light pipe 110 and the light incident surface 106 of the fly-eye lens 114, which is an amplitude division integrator, are optically conjugated with each other by the field lens 112. As a result, a surface light source having a uniform intensity distribution on the light exit surface 110 ′ is imaged on the light incident surface 106 of the fly-eye lens 114, and light having a uniform cross-sectional intensity distribution is formed on the light incident surface 106 of the fly-eye lens 114. Is incident. The fly-eye lens 114 forms a plurality of light sources (secondary light sources) on its light exit surface, and a condenser lens system (not shown) superimposes light beams from the plurality of light sources on a reticle (not shown) to form a reticle pattern. The whole is illuminated with uniform light intensity.

[0011]

In the recent production of highly integrated semiconductor devices such as VLSIs, extremely high uniformity of the illuminance distribution required when printing circuit patterns is required. ing.

In an exposure apparatus using light in the vacuum ultraviolet region as exposure light, usable glass materials are limited in the vacuum ultraviolet region, and the transmittance is low due to absorption of ultraviolet light by the glass material. In such a case, there are the following problems.

In order to form a uniform surface light source on the exit surface of the light pipe, it is better to increase the number of times of internal reflection of the divergent light beam. For this purpose, the diameter may be fixed and the length of the light pipe may be increased. However, if the length is increased, the transmittance decreases due to absorption. For this reason, it cannot be made longer than a certain length.

That is, if the transmittance is prioritized, the length becomes insufficient, and as a result, it becomes difficult to obtain a uniform surface light source.

In order to form a uniform surface light source on the exit surface of the light pipe, the number of internal reflections can be increased by fixing the length of the light pipe and reducing the diameter. However, in this case, the energy density of the incident light flux per section of the light pipe increases, and the durability of the glass material decreases.

That is, considering the durability of the glass material, the diameter of the pipe cannot be reduced to a certain degree or more, and as a result, it becomes difficult to obtain a uniform surface light source.

The present invention further improves the illuminating device proposed earlier by the present applicant, for example, by appropriately setting the configuration of a luminous flux mixing means having a light pipe, thereby obtaining an inner surface necessary for obtaining a uniform surface light source. A lighting device suitable for use in a semiconductor device manufacturing apparatus that maintains the number of reflections, makes the illuminance distribution on the surface to be illuminated uniform, and at the same time improves the transmittance, and improves the light collection efficiency. And a projection exposure apparatus.

[0018]

The illumination device according to the present invention comprises: (1-1) a light source, a light beam splitting element for splitting a light beam from the light source into a plurality of light beams, and a light beam diverging from the light beam splitting device at a constant divergence angle. It has a plurality of light pipes each of which mixes a plurality of light beams and emits light at an angle corresponding to the divergence angle, a light beam mixing means, and an optical means for illuminating an irradiation surface with a plurality of light beams from the light beam mixing means. It is characterized by doing.

(1-2) A light source, an emission angle preserving optical element for emitting a light beam from the light source at a constant divergence angle, and a condensing optical system for condensing the light beam from the emission angle preserving optical element.
A light beam splitting element for splitting the light beam from the light-collecting optical system into a plurality of light beams, a plurality of light pipes for mixing the plurality of light beams from the light beam splitting element, a light beam mixing means, and a light beam mixing means; A zoom optical system for projecting the light beam on a predetermined surface at a desired magnification, a multi-beam generating means for dividing the light beam from the zoom optical system into multiple light beams, and a light beam from the multi-beam generating device on an irradiation surface. And illumination means for irradiating the light with superposition.

(1-3) A light source, a light beam splitting element for splitting a light beam from the light source into a plurality of light beams, a light collecting optical system for collecting a plurality of light beams from the light beam splitting element, and the light collecting device A plurality of light pipes for mixing a plurality of light beams from the optical system, a bundle of light beams, a zoom optical system for projecting a light beam from the light beam mixing unit onto a predetermined surface at a desired magnification, and the zoom optical system A multi-beam generating means for dividing a light beam from the multi-beam generating means into a multi-beam, and an illuminating means for irradiating the light beam from the multi-beam generating means onto the irradiation surface in a superimposed manner.

In particular, (1-1-1) the light beam splitting element is set at an angle of emission based on a change in the projection magnification when the light beam from the light beam mixing means is projected onto the multi-beam light generation means by the zoom optical system. Switching to a different beam splitting element to adjust the numerical aperture of the beam incident on the multi-beam generator.

(1-1-2) The exit angle preserving optical element is composed of a fly-eye lens in which a plurality of minute lenses are two-dimensionally arranged.

(1-1-3) The light beam mixing means forms a plurality of light source virtual images by using an inner reflection surface of the incident light beam,
A plurality of light pipes are bundled so that light beams from the plurality of light source virtual images overlap near the exit surface.

(1-1-4) The light beam splitting element is composed of a lens array in which a plurality of minute lenses are two-dimensionally arranged.

(1-1-5) The diameter of a light beam incident on the light beam splitting element based on a change in the projection magnification when the light beam from the light beam mixing means is projected onto the multi-beam light generation means by the zoom optical system. Is switched to adjust the numerical aperture of the light beam incident on the multiple light beam generating means.

(1-1-6) The light beam splitting element is characterized by being composed of a diffractive optical element.

The projection exposure apparatus according to the present invention provides (2-1) a pattern on a first object surface provided on a surface to be illuminated by a light beam from the illumination device having the configuration (1-1) by a projection optical system. The projection is performed on the second object plane.

According to the device manufacturing method of the present invention, (3-1) a pattern on the reticle surface is illuminated with a light beam from the illuminating device having the configuration (1-1), and the pattern is projected on a wafer surface by a projection optical system. Then, after the exposure, the device is manufactured through a developing process.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view of a main part of a lighting device according to a first embodiment of the present invention. The figure shows a case where the present invention is applied to a reduction type projection exposure apparatus called a stepper for manufacturing a semiconductor element (device) using an illumination apparatus as an example.

In FIG. 1, reference numeral 1 denotes a light source (light source means) such as an ultra-high pressure mercury lamp or an excimer laser which emits ultraviolet light or far ultraviolet light.

Numeral 11 denotes a beam expander for converting the diameter of a light beam from the laser light source 1 into a desired shape, and numeral 2 denotes an emission angle preserving optical element which emits an incident light beam at a constant emission angle. Reference numeral 3 denotes a condensing optical system, which condenses the light beam from the emission angle preserving optical element 2 and guides the light beam to a lens array (light beam splitting element) 12. The lens array 12 has a plurality of microlenses arranged two-dimensionally, and has a plurality of secondary light sources formed on an exit surface thereof. Reference numeral 4 denotes a light beam mixing means in which a plurality of short light pipes are combined in parallel, and the light beams from the lens array 12 are mixed to form a uniform illuminance distribution on the exit surface. Reference numeral 5 denotes a zoom optical system which converts the light beam from the light beam mixing means 4 into an incident surface 7a of the multi-beam light generation means 7.
At different magnifications. The multi-beam generating means 7 forms a light source image having a uniform illuminance distribution on its exit surface 7b. Reference numeral 8 denotes irradiation means including a condenser lens and the like.
The luminous flux from the multiple luminous flux generating means 7 is condensed to illuminate an irradiation surface 9 such as a mask or a reticle (hereinafter referred to as “reticle”).

The pattern drawn on the reticle arranged on the irradiated surface 9 is reduced and projected on a photosensitive substrate (wafer) by a projection optical system (not shown).

The zoom optical system 5, the multi-beam generating means 7,
The irradiation means 8 constitutes one element of the optical means.

Next, the configuration of each element shown in FIG. 1 will be described.

The exit angle preserving optical element 2 includes an aperture (aperture) 21 and a lens system 22 as shown in FIG. The incident light beam is, for example, light beam 27 (optical axis 2).
7aa), the light beam 28 (optical axis 28a) has optical properties such that even if the light beam is slightly fluctuated in the direction perpendicular to the optical axis, the light beam emitted therefrom has a constant exit angle 29a.

The exit angle preserving optical element 2 is shown in FIG.
As shown in (B), a fly-eye lens composed of a plurality of microlenses 23 may be used. In this case, the exit angle 29 b of the light beam is determined by the shape of the fly-eye lens 23. Also in this case, the optical axis of the incident light beam slightly fluctuates and the light beam 27
Even when the light beam is incident in the state of (optical axis 27a) or the light beam 28 (optical axis 28a), the emission angle 29b of the emitted light beam is constant.

As shown in FIG. 3, the light beam mixing means 4 has a shape in which, for example, four quadrangular prism-shaped light pipes 4a, 4b, 4c and 4d each having a vertical and horizontal length of D 'and a length of L' are bundled. doing. Each light pipe is made of a glass rod using a light-transmitting glass material suitable for illumination, or a pipe-shaped optical element in which a flat reflecting surface is hollow and a flat reflecting surface is positioned inside. .

Here, the shape of the general light beam mixing means 4 will be described. For example, assuming that the diameter of the light pipe 110 shown in FIG. 10 is D and the length is L, it is necessary to increase the value of the ratio R = L / D in order to increase the number of times of internal reflection.

For this purpose, the length L is increased or the diameter D is increased.
However, as described in the conventional problem, this causes a decrease in transmittance due to a glass material thickness and a decrease in durability due to an increase in cross-sectional energy density, particularly in an ultraviolet wavelength region. , There is a limit on the size.

Now, the ratio of the pipe shape shown in FIG.
In D, if uniformity is achieved, if the shape is changed so as to maintain the ratio, the number of times of internal reflection is the same, for example, a thin and light pipe whose size is proportional to the light pipe 110 in the example of FIG. If the short pipe 4a is used, the uniformity of the exit end face is the same.

In this embodiment, the light pipes 4b, 4c, 4c, 4c, 4c, 4c, 4c, 4c have the same shape as the light pipe 4a so that the area of the exit end 4out becomes a desired size.
b are bundled so that the same amount of divergent light beams are incident on the respective incident end faces. As a result, the light beam mixing means 4 having a short length is obtained without increasing the light energy density.

In this embodiment, four light pipes are bundled, but the present invention is not limited to this, and a bundle of two or more light pipes can be used as the light mixing means. The multi-beam generating means 7 is composed of a fly-eye lens comprising a plurality of microlenses, a fiber bundle, etc.
Forms a light source surface composed of a plurality of point light sources. In the present embodiment, the multi-beam generating means 7 has a plurality of optical axes, has a finite area around each optical axis, and can specify one light beam in each of the regions. Such an optical element is referred to.

Next, the optical operation of the illumination device of the present embodiment will be described.

The light beam emitted from the laser light source 1 passes through the beam expander 11 and a light beam drawing optical system (not shown) composed of a mirror and a relay lens, and is incident on the incident surface 2a of the emission angle preserving optical element 2.

The light beam emitted from the exit surface 2b of the exit angle preserving optical element 2 at a desired exit angle 2 'is condensed by the condensing optical system 3, and is exited from the exit surface 2b of the exit angle preserving optical element 2.
Is introduced into the lens array 12 arranged so that the incident surface 12 'substantially coincides with the Fourier transform surface.

In this embodiment, as shown in FIG. 3, the light beam mixing means 4 is composed of a bundle of four light pipes 4a to 4d. It is constituted by four lenses so that a light beam can be introduced into the end face 4in.

Desired divergence angle 1 from lens array 12
The equally split luminous flux diverging at 2 ″ is introduced into the luminous flux mixing means 4. The divergent luminous flux incident on the luminous flux mixing means 4 is
A plurality of apparent light source images of the laser light source 1 are formed in a plane that passes through the inner surface of the laser light source 1 while being reflected multiple times and is perpendicular to the optical axis.
Therefore, the exit surface 4out when the bundled surface is viewed as one
In this case, the illuminance distribution on the emission surface 4out becomes uniform by adding together the laser beams that appear as if emitted from a plurality of apparent light sources. This will be described later with reference to FIG. The exit surface 4out having this uniform illuminance distribution is converted into a desired magnification m by the zoom optical system 5.
The light is projected as a uniform light source image 6 on the incident surface 7a of the multi-beam generating means 7. Here, the desired magnification is a magnification for setting the size of the uniform light source image 6 such that the incident angle 19 of the irradiation light beam on the irradiation surface 9 becomes an optimal value for exposure.

Now, for a desired magnification m, the zoom optical system 5
Assuming that the incident side NA determined by the incident angle 15 to the laser beam is NA ′ and the emission side NA determined by the exit angle 16 is NA ″, NA ′ = m · NA ″ (1) is established. Here, it is desirable from the viewpoint of illumination efficiency that the magnitude of the exit angle 16 be as close as possible within a range not exceeding the incident NA of the multi-beam generating means 7. The optimal angle is set depending on the angle. Therefore, as shown by the equation (1), when the optimum magnification for exposure under certain conditions is determined, the optimum angle of the exit angle 15 from the light beam mixing means 4 is also determined.

This embodiment utilizes the fact that the value of the angle 15 to the zoom optical system 5 is equal to the divergence angle of the light beam entering the light beam mixing means 4 and therefore depends on the exit angle 12 ″ of the lens array 12. This is achieved by switching the lens array 12 according to the illumination conditions, which will be described later with reference to FIG.

When the uniform light source image 6 is projected on the incident surface 7a of the multi-beam generating means 7 as described above, the intensity distribution of the incident surface is directly transferred to the exit surface 7b. The intensity distribution of 7b is uniform.

By irradiating the emitted light beams from the respective minute areas of the multi-beam generating means 7 onto the irradiated surface 9 by the irradiating means 8 in a superimposed manner, the illuminance on the entire irradiated surface 9 is uniform. Illuminated to be distributed.

Next, the switching control of the lens array 12 will be described in detail with reference to FIGS. In each figure, 12a is a lens array having a small exit angle 12'a, and 12b is a lens array having a large exit angle 12'b. Others are the same as those described in FIG.

In general, in an illumination device used in a semiconductor device manufacturing apparatus, it is required to set an incident angle of a light beam incident on the surface 9 to be irradiated to a desired angle. In the present embodiment, a plurality of lens arrays 12 are prepared,
The angle of incidence on the illuminated surface is set to a desired angle by switching this according to a request.

FIG. 4A shows a case where the incident angle 19a of the light beam incident on the irradiated surface 9 is relatively small (this is called a small σ value). In the present embodiment, in order to reduce the σ value, the incident surface 7a of the multi-beam generating means 7 is required.
On top of this, it is necessary to form an image 6a on the exit surface 4out of the light beam mixing means 4 with a small magnification. This is achieved by changing the magnification of the zoom optical system 5. As described above, the value of the emission angle 16a is set to an optimum angle depending on the multi-beam generating means 7.

Therefore, as shown by the equation (1), when the magnification for obtaining the desired σ value is determined, the light beam mixing means 4
Is also uniquely determined. The exit angle 15a is determined by the incident surface 4i of the plurality of light pipes constituting the light beam mixing means 4.
n is determined by the divergence angle 12'a of the light beam incident on the lens array 12a.
Control is performed by setting it to 2'a. As described above, the illumination efficiency is high, and the incident angle 19a is small (that is, the σ value is small).
Lighting is on.

FIG. 4B shows an embodiment in which the σ value is large. In this case, the emission angle 12 '
By switching to the lens array 12b where b is large, the emission angle 12'b is increased, whereby the divergence angle of the light beam incident on the light beam mixing means 4 is increased, and the light beam diverging from the exit end 4out of the light beam mixing means 4 Angle of 15
Increase b. Then, even if the image 6b of the exit end 4out is projected onto the light beam mixing means 7 at a large magnification, the angle 16b can be made substantially the same as the above-mentioned angle 16a from the relationship of the expression (1). As described above, illumination with high illumination efficiency and a large incident angle 19b (that is, a large σ value) is performed.

Next, the uniformity of the illuminance distribution on the exit surface 4out of the light beam mixing means 4 will be described in detail using one light pipe 4a shown in FIG.

The luminous flux mixing means 4 is used in this embodiment.
Since a plurality of prismatic light pipes having the same shape are bundled, one of the light pipes 4a is described with reference to a cross-sectional view including the incident optical axis in FIG.

First, the lens array 12 (FIG. 5) shown in FIG.
(Not shown in FIG. 1) once becomes a divergent light beam having a divergence angle 41 after being once converged to the focal point P0. At this time, when the light beam is an excimer laser beam, it generally has a high output and therefore has an enormous energy density near the focal point P0, which may damage the coating of the light pipe 4a or the glass material itself. The light pipe 4a is arranged at a distance.

The divergent light beam incident on the light pipe 4a is:
After passing through the inner flat reflecting surface while being repeatedly reflected, the light is emitted while maintaining the divergence angle 41 at the time of incidence.
At this time, since the luminous flux reflected at each portion is still diverging after the reflection, the reflected luminous flux is rearwardly reflected by a plurality of virtual images P1, P2, P as shown by the broken lines.
3, P4, P5, P6, P7, P8, P9, P10 are formed.

Although not shown in FIG. 5, in the case of a quadrangular prism light pipe, a virtual image similar to the above is further two-dimensionally formed by the divergent light beams reflected by the left and right (perpendicular to the paper) inner reflecting surfaces. As a result, the virtual light source images are arranged in a grid pattern, which forms one minute element of the multi-beam generating means 7.

This means that the number of effective light sources when irradiating the light beam from the multi-beam generating means 7 onto the irradiated surface 9 by the irradiating means 8 is very large. 9 is illuminated so as to have a uniform illuminance distribution as a whole.

As described with reference to FIG. 2, even if the light beam from the laser light source 1 slightly fluctuates due to disturbance by the emission angle storage optical element 2, the emission angle is preserved. Is only slightly changed, and there is no change in the lattice-like virtual image sequence, and there is almost no change when the entire light source image in the micro lens of the multi-beam generating means 7 is viewed macroscopically. Therefore, the influence on the illuminance distribution on the surface to be illuminated 9 is so small as to be negligible.

This indicates that the present embodiment is a system which is very stable against fluctuations in the luminous flux from the laser light source.

Accordingly, the light beam mixing means 4 constituted by bundling a plurality of light pipes having the same shape as the light pipe 4a has a very large number of light source virtual images and is uniformly uniform on the surface 9 to be irradiated. Illumination is performed so as to have an appropriate illumination distribution.

In this embodiment, the multi-beam generating means 7 is used.
The irradiation means 8 may be omitted, the irradiated surface 9 may be arranged at the position of the uniform light source image 6 formed by the zoom optical system 5, and the laser light beams may be added.

FIG. 6 is a schematic view of a main part of a second embodiment of a projection exposure apparatus for manufacturing a semiconductor device using the illumination apparatus of the present invention. In the figure, the same elements as those shown in FIG. 1 are denoted by the same reference numerals.

In the figure, reference numeral 91 denotes a light beam shaping optical system for shaping a coherent light beam from the laser light source 1 into a desired beam shape. Reference numeral 92 denotes an incoherent optical system for incohering a coherent laser beam. Reference numeral 93 denotes a projection optical system of the exposure apparatus, and reference numeral 94 denotes a photosensitive substrate coated with a photosensitive material such as a wafer. The description of the same numbers as in FIG. 1 is omitted.

The light beam emitted from the laser light source 1 enters a light beam shaping optical system 91 via a light beam drawing optical system including a mirror and a relay lens (not shown). The light beam shaping optical system 91 is composed of a plurality of cylindrical lenses or beam expanders, and converts the aspect ratio of the light beam cross-sectional shape into a desired value.

The light beam shaped by the light beam shaping optical system 91 is incident on the incoherent optical system 92 for the purpose of preventing light from interfering on the wafer surface 94 via mirrors 98 and 99 and causing speckle. And converted into an incoherent light flux.

The incoherent optical system 92 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, as disclosed in, for example, Japanese Patent Application Laid-Open No. 3-215930. After that, a folding system in which one light beam is given an optical path length difference greater than the coherence length of the light beam through an optical member, and then re-guided to the divided surface, and is emitted while being superimposed on the other light beam Are used to form a plurality of mutually incoherent light beams.

The light beam thus made incoherent is incident on the emission angle preserving optical element 2.

According to the procedure already described with reference to FIG. 1, the luminous flux emitted from each minute area of the multi-beam generating means 7 is irradiated by the irradiating means 8 so as to be superimposed on the reticle R on the surface 9 to be illuminated. The irradiation surface 9 is illuminated so as to have a uniform illuminance distribution as a whole.

A light beam having information such as a circuit pattern on the reticle R surface formed on the irradiated surface 9 is projected and imaged on a photosensitive substrate 94 by a projection optical system 93 at a magnification optimal for exposure. Exposure of the circuit pattern is being performed.

The photosensitive substrate is fixed to a photosensitive substrate stage (not shown) by vacuum suction or the like, and has a function of moving up and down and back and forth on the paper surface, and the movement is also performed by a length measuring device such as a laser interferometer (not shown). Is controlled by a vessel.

FIG. 7 is a schematic view of a main part of a third embodiment of the lighting device of the present invention. In the figure, the same elements as those shown in FIG. 1 are denoted by the same reference numerals.

In the figure, 1 is a laser light source such as an excimer laser, 11 is a beam expander for converting a light beam diameter from the laser light source into a desired shape, 201 is a light beam splitting element, and converts an incident light beam into a plurality of light beams. It consists of a diffractive optical element for branching. Reference numeral 3 denotes a condensing optical system, 4 denotes a light beam mixing means including a plurality of short light pipes, 5 denotes a zoom optical system, 7 denotes a multi-beam generating means, 8 denotes irradiation means including a condenser lens, and 9 denotes a mask or a reticle. The surface to be irradiated.

In the figure, a light beam emitted from a laser light source 1 enters a beam expander 11 via a light beam drawing optical system including a mirror and a relay lens (not shown), where the light beam has a desired beam diameter 202. Is converted to
It is incident on the diffractive optical element 201.

The diffractive optical element 202 may be one having a linear grating arranged on both sides of a transparent substrate so as to intersect each other, or one having a lattice pattern formed on the one side of the substrate in a vertical and horizontal lattice pattern from the beginning. Used.

The diffractive optical element 201 splits the incident light beam toward the light-collecting optical system 3 into light beams in four directions. This is because the ± 1st-order diffracted light diffracted by the linear grating in one direction is further divided into ± 1st-order diffracted light by the linear grating in the other direction, which is orthogonal to the optical axis of the incident light beam. Has branched to.

The four light beams thus divided are condensed by the light condensing optical system 3 and output as a light beam having a desired divergence angle 203 to the light beam mixing means 4 composed of four light pipe bundles. Has been introduced.

In this embodiment, the light beam mixing means 4
Is composed of four light pipes.
It is also possible to use a plurality of light pipes, such as bundling into × 3, and to optimize the diffraction direction of the diffractive optical element 201 accordingly.

The divergent light beam incident on the light beam mixing means 4 is:
As described with reference to FIG. 1, by irradiating the irradiation surface 8 with the irradiation unit 8 in a superimposed manner, the irradiation surface 9 is illuminated so as to have a uniform illuminance distribution as a whole.

Even if the light beam from the laser light source 1 fluctuates minutely due to disturbance, the divergence angle 203 is preserved since the beam diameter 202 does not change and the optical axis only slightly displaces. Each of the light source virtual images only slightly fluctuates, and there is no fluctuation in the lattice-like virtual image sequence. There is almost no fluctuation when the entire light source image in the micro lens of the multi-beam generating means 7 is macroscopically viewed. Therefore, the influence on the illuminance distribution on the surface to be illuminated 9 is so small as to be negligible.

This indicates that the present embodiment is a system that is very stable against fluctuations in the luminous flux from the laser light source.

This embodiment can be applied to an exposure apparatus as shown in FIG.

Next, an embodiment of a method of manufacturing a semiconductor device using the above-described projection exposure apparatus will be described.

FIG. 8 shows a flow of manufacturing a semiconductor device (a semiconductor chip such as an IC or an LSI, or a liquid crystal panel or a CCD).

In step 1 (circuit design), a circuit of a semiconductor device is designed. Step 2 is a process for making a mask on the basis of the circuit pattern design.

In step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon. Step 4
The (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the prepared mask and wafer.

The next step 5 (assembly) is called a post-process, and is a step of forming a semiconductor chip using the wafer produced in step 4, and includes an assembly step (dicing and bonding) and a packaging step (chip encapsulation). And the like.

In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7).

FIG. 9 shows a detailed flow of the wafer process. Step 11 (oxidation) oxidizes the wafer's surface. Step 12 (CVD) forms an insulating film on the wafer surface.

In step 13 (electrode formation), electrodes are formed on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted into the wafer. Step 15
In (resist processing), a photosensitive agent is applied to the wafer. Step 16 (exposure) uses the above-described exposure apparatus to print and expose the circuit pattern of the mask onto the wafer.

In step 17 (development), the exposed wafer is developed. In step 18 (etching), portions other than the developed resist are removed. In step 19 (resist stripping), unnecessary resist after etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer.

By using the manufacturing method of this embodiment, it is possible to manufacture a highly integrated semiconductor device which has conventionally been difficult to manufacture.

[0097]

According to the present invention, by setting each element as described above, the number of internal reflections required to obtain a uniform surface light source is maintained, and the illuminance distribution on the surface to be irradiated is made uniform. At the same time, it is possible to achieve an illumination device suitable for a semiconductor device manufacturing apparatus and a projection exposure apparatus using the same, which simultaneously improve transmittance and improve light collection efficiency.

In particular, according to the present invention, the angle of incidence of the light beam on the surface to be irradiated can be set to a desired value, and highly efficient uniform illumination can be performed. Effects such as stabilization of the incident angle of the light beam on the irradiation surface and uniform illumination with high efficiency even when using a glass material having relatively large absorption can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a main part of a lighting device according to a first embodiment of the present invention.

FIG. 2 is an explanatory view of a part of the first embodiment.

FIG. 3 is an explanatory diagram of a part of the first embodiment;

FIG. 4 is an explanatory diagram when a part of the first embodiment is replaced.

FIG. 5 is an explanatory diagram of a part of the first embodiment.

FIG. 6 is a schematic view of a main part of a second embodiment of a projection exposure apparatus using the illumination device of the present invention.

FIG. 7 is a schematic diagram of a main part of a lighting device according to a third embodiment of the present invention.

FIG. 8 is a flowchart of a device manufacturing method of the present invention.

FIG. 9 is a flowchart of a wafer process.

FIG. 10 shows a lighting device proposed by the applicant of the present invention.

[Explanation of symbols]

 1: Laser light source 2: Emission angle preserving optical element 3: Condensing optical system 12: Light beam splitting element 4: Light beam mixing means 5: Zoom optical system 7: Multi-beam light generating optical system 8: Irradiating means 9: Irradiated surface 11: Beam expander

Claims (11)

[Claims] 1. A light source, a light beam splitting element for splitting a light beam from the light source into a plurality of light beams, and a plurality of light beams emitted from the light beam splitting device at a constant divergence angle are mixed, and an angle corresponding to the divergence angle is mixed. An illumination device, comprising: a plurality of light pipes that are bundled by the light beam mixing means; and a light means for illuminating an irradiation surface with a plurality of light beams from the light beam mixing means. 2. A light source, an emission angle preserving optical element for emitting a light beam from the light source at a constant divergence angle, a condensing optical system for condensing a light beam from the emission angle preserving optical element, and the condensing optical system A light beam splitting element for splitting a light beam from the system into a plurality of light beams, a plurality of light pipes for mixing a plurality of light beams from the light beam splitting device, a light beam mixing means, and a light beam from the light beam mixing means. A zoom optical system for projecting at a desired magnification onto a surface, multi-beam generating means for dividing a light beam from the zoom optical system into multi-beams, and superimposing the light beams from the multi-beam generating means on an irradiation surface. A lighting device, comprising: lighting means for irradiating. 3. A light source, a light beam splitting element for splitting a light beam from the light source into a plurality of light beams, a condensing optical system for condensing a plurality of light beams from the light beam splitting element, and a light condensing optical system A plurality of light pipes for mixing the plurality of light beams, a light beam mixing means, a light beam from the light beam mixing means, a zoom optical system for projecting a light beam at a desired magnification onto a predetermined surface, and a light beam from the zoom optical system A multi-beam generating means for dividing the light beam into multi-beams, and an illuminating means for irradiating the superposed light beams from the multi-beam generating means on an irradiation surface. 4. The light beam splitting element is switched to a light beam splitting element having a different emission angle based on a change in projection magnification when the light beam from the light beam mixing means is projected onto the multi-beam generating means by the zoom optical system. 3. The lighting device according to claim 1, wherein the numerical aperture of the light beam incident on said multi-beam generating means is adjusted. 5. The illuminating device according to claim 1, wherein said exit angle preserving optical element comprises a fly-eye lens in which a plurality of minute lenses are two-dimensionally arranged. 6. The light beam mixing means forms a plurality of light source virtual images using an inner reflecting surface of an incident light beam, and a plurality of light pipes in which light beams from the plurality of light source virtual images overlap near an exit surface. The lighting device according to claim 1, wherein the lighting device is configured to be bundled. 7. The illuminating device according to claim 1, wherein said light beam splitting element comprises a lens array in which a plurality of minute lenses are two-dimensionally arranged. 8. A size of a light beam diameter incident on the light beam splitting element is switched based on a change in a projection magnification when the light beam from the light beam mixing means is projected onto the multi-beam light generation means by the zoom optical system. 3. The lighting device according to claim 1, wherein the numerical aperture of the light beam incident on said multi-beam generating means is adjusted. 9. The illuminating device according to claim 3, wherein said light beam splitting element comprises a diffractive optical element. 10. A pattern on a first object surface provided on a surface to be illuminated by a light beam from the illuminating device according to claim 1 and projected onto a second object surface by a projection optical system. A projection exposure apparatus characterized in that the projection is performed on the projection exposure apparatus. 11. A pattern on a reticle surface is illuminated by a light beam from the illuminating device according to any one of claims 1 to 9, and the pattern is projected onto a wafer surface by a projection optical system, and the pattern is exposed. A method of manufacturing a device, wherein the device is manufactured through a wafer development process.