JP2002083759A - Illuminating optical equipment, and aligner equipped with the illuminating optical equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide illuminating optical equipment which can substantially reduce a speckle pattern occurrences caused by diffraction optical element used for, for example, transformed illumination. SOLUTION: This illuminating optical equipment is equipped with a light source means (1) for supplying luminous flux, a luminous flux converting element (6) for converting the luminous flux from the light source means (1) into luminous flux at a prescribed cross section, a condensing optical system (7) for condensing the light from the luminous flux from the luminous flux converting element, and an optical integrator (8) for uniformly illuminating the faces (M and W) to be irradiated, receiving the light from the condensing optical system. The luminous flux converting element and the front focus position of the condensing optical condensing system area prescribed distance apart from each other, so as to substantially reduce the speckle pattern which occurs, being caused by the luminous flux converting element at the face to be irradiated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating optical apparatus and an exposure apparatus having the illuminating optical apparatus, and more particularly, to manufacturing a micro device such as a semiconductor device, an imaging device, a liquid crystal display device, or a thin film magnetic head by a lithography process. Optical device suitable for an exposure apparatus for use in the present invention.

[0002]

2. Description of the Related Art In a typical exposure apparatus of this kind,
The light beam emitted from the light source enters the fly-eye lens,
Then, a secondary light source including a large number of light sources is formed on the side focal plane. The light flux from the secondary light source is restricted via an aperture stop arranged near the rear focal plane of the fly-eye lens, and then enters the condenser lens. The aperture stop limits the shape or size of the secondary light source to a desired shape or size according to a desired illumination condition (exposure condition).

The light beam condensed by the condenser lens illuminates a mask on which a predetermined pattern is formed in a superimposed manner. The light transmitted through the mask pattern forms an image on the wafer via the projection optical system. Thus, on the wafer,
The mask pattern is projected and exposed (transferred). Note that the pattern formed on the mask is highly integrated, and it is essential to obtain a uniform illuminance distribution on the wafer in order to accurately transfer this fine pattern onto the wafer.

In recent years, illumination coherency σ (σ) has been changed by changing the size of an aperture (light transmitting portion) of an aperture stop arranged on the exit side of a fly-eye lens.
Value = aperture stop diameter / pupil diameter of projection optical system, or σ value = exit side numerical aperture of illumination optical system / incident side numerical aperture of projection optical system)
Attention has been focused on technologies that change the temperature. In addition, by setting the shape of the opening of the aperture stop arranged on the emission side of the fly-eye lens to an annular shape or a four-hole shape (ie, a quadrupole shape), the secondary light source formed by the fly-eye lens is formed. Attention has been paid to a technology for improving the depth of focus and the resolving power of a projection optical system by limiting the shape to an annular shape or a quadrupole shape.

[0005]

By the way, the secondary light source is formed by a fly-eye lens in order to restrict the shape of the secondary light source to a ring shape or quadrupole shape and perform deformed illumination (ring zone illumination or quadrupole illumination). If the light flux from the relatively large secondary light source is simply limited by an aperture stop having an annular or quadrupole aperture,
A substantial part of the light beam from the secondary light source is blocked by the aperture stop,
Does not contribute to illumination (exposure). As a result, the illuminance on the mask and the wafer is reduced due to the loss of light amount in the aperture stop, and the throughput as an exposure apparatus is also reduced.

Therefore, for example, a light flux converted into an annular shape or a quadrupole shape through a diffractive optical element is incident on a fly-eye lens, and a secondary light source in the annular or quadrupolar shape is formed on the exit side of the fly-eye lens. Configurations are possible. However, when a diffractive optical element is arranged in an illumination optical path in an exposure apparatus using an excimer laser light source, for example, a speckle pattern (interference pattern, interference noise) caused by the diffractive optical element on a mask or a wafer to be irradiated is generated. appear.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and provides an illumination optical apparatus and a lighting apparatus capable of substantially reducing a speckle pattern generated due to a diffractive optical element used for deformed illumination. An object of the present invention is to provide an exposure apparatus including the illumination optical device. Another object of the present invention is to provide a method for manufacturing a micro device capable of manufacturing a good micro device with high throughput and high resolution using deformed illumination in which a speckle pattern is substantially reduced. I do.

[0008]

According to a first aspect of the present invention, there is provided an illumination optical apparatus for illuminating a surface to be illuminated, comprising: a light source for supplying a light beam; A light beam conversion element for converting the light beam of the predetermined cross section or a light beam of a predetermined light intensity distribution, and a condensing optical system for condensing light from the light beam conversion element,
An optical integrator for uniformly illuminating the irradiated surface by receiving light from the light-collecting optical system, and a light guiding optical system for guiding a light beam from the optical integrator to the irradiated surface; The light-flux conversion element and the front focal position of the light-converging optical system are separated by a predetermined distance to substantially reduce a speckle pattern generated by the light-flux conversion element on the irradiated surface. An illumination optical device is provided.

According to a second aspect of the present invention, in an illumination optical device for illuminating a surface to be illuminated, a light source means for supplying a light beam, and a light beam from the light source means having a predetermined cross section or a predetermined light intensity distribution. A light beam conversion element for converting the light beam into a light beam, and a light condensing optical system disposed between the light source means and the light beam conversion element for condensing the light beam at a predetermined position; The predetermined position where the light beam is condensed by the light condensing optical system is separated by a predetermined distance in order to substantially reduce a speckle pattern generated due to the light beam conversion element on the irradiated surface. And an illumination optical device, wherein the illumination optical device is disposed at a distance from the illumination optical device.

According to a preferred aspect of the second invention, the predetermined position at which the light beam is collected by the light collecting optical system is a rear focal position of the light collecting optical system.

According to a third aspect of the present invention, in an illumination optical device for illuminating a surface to be illuminated, a light source means for supplying a light beam, and a light beam from the light source means having a predetermined cross section or a predetermined light intensity distribution. A light beam converting element for converting into a light beam, a light collecting optical system for collecting light from the light beam converting element, and uniformly illuminating the irradiated surface by receiving light from the light collecting optical system An optical integrator, a light guiding optical system for guiding a light beam from the optical integrator to the irradiated surface, and a temporal average of a speckle pattern generated on the irradiated surface due to the light beam converting element. And a driving means for reciprocating the light beam converting element along the optical axis.

According to a fourth aspect of the present invention, there is provided a light source for supplying a light beam for illuminating a surface to be illuminated, and a light beam from the light source disposed between the light source and the surface to be illuminated. A light beam converting element for converting the light beam into a light beam having a predetermined cross section or a light beam having a predetermined light intensity distribution, and adjusting means for adjusting the light beam converting element according to a change in illumination conditions on the irradiated surface. An illumination optical device is provided.

According to a preferred aspect of the fourth invention, the apparatus further comprises a front light condensing optical system disposed between the light source means and the light beam conversion element for condensing the light beam at a predetermined position. Further, it is preferable that the apparatus further comprises a rear light condensing optical system disposed between the light beam conversion element and the irradiated surface for condensing light from the light beam conversion element. In this case, it is preferable that the apparatus further includes an optical integrator that is arranged in an optical path between the rear light condensing optical system and the irradiation surface and uniformly illuminates the irradiation surface.

According to a fifth aspect of the present invention, in an illumination optical device for illuminating a surface to be illuminated, a light source means for supplying a light beam, and a light beam from the light source means having a predetermined cross section or a predetermined light intensity distribution. A first light beam conversion element for converting the light beam into a light beam, a first variable power optical system for condensing the light beam from the first light beam conversion element, and a light beam from the first variable power optical system having a predetermined cross section. A second light beam converting element for converting the light beam or a light beam having a predetermined light intensity distribution, a second variable power optical system for condensing the light beam from the second light beam converting element, and the second variable power optical system An optical integrator for receiving a light beam from the system and uniformly illuminating the irradiated surface; and a light guiding optical system for guiding a light beam from the optical integrator to the irradiated surface, wherein the second light beam conversion is performed. The element is the first variable magnification. Collecting by Manabu based light position or the second
An illumination optical device is provided, which is arranged at a predetermined distance from a front focal position of a variable power optical system.

[0015] According to a preferred aspect of the fifth aspect of the present invention, there is further provided adjusting means for adjusting one of the first light beam conversion element and the second light beam conversion element in accordance with a change in illumination conditions. . In this case, one of the first light beam conversion element and the second light beam conversion element has a first diffractive optical element and a second diffractive optical element that are provided so as to be interchangeable with each other. It is preferable that the first diffractive optical element or the second diffractive optical element is adjusted according to switching between the first diffractive optical element and the second diffractive optical element.

Preferably, the adjusting means performs at least one of a movement adjustment along the optical axis, a movement adjustment along a direction orthogonal to the optical axis, and an inclination adjustment with respect to the optical axis. Further, it is preferable that the adjusting unit adjusts the first diffractive optical element or the second diffractive optical element according to a change in a shape ratio of the secondary light source accompanying a magnification change of the first variable power optical system. .

According to a sixth aspect of the present invention, there is provided an illumination optical device according to the first to fifth aspects, and a projection optical system for projecting and exposing a mask pattern set on the surface to be irradiated onto a photosensitive substrate. An exposure apparatus characterized by comprising:

In a seventh aspect of the present invention, an exposure step of exposing the pattern of the mask onto the photosensitive substrate by the exposure apparatus of the sixth aspect, and a developing step of developing the photosensitive substrate exposed in the exposure step And a method of manufacturing a microdevice.

According to an eighth aspect of the present invention, there is provided a microdevice comprising: an illumination step of illuminating a mask using an illumination system; and a transfer step of projecting and transferring a pattern image of the mask onto a photosensitive substrate using a projection system. In the manufacturing method, the illuminating step includes a changing step of changing an illuminating condition for the mask, and adjusting a diffractive optical element in the illuminating system according to the change of the illuminating condition by the changing step. And a method for producing the same.

[0020]

DETAILED DESCRIPTION OF THE INVENTION In a typical embodiment of the invention,
The light beam from the light source means is converted into a light beam having a predetermined cross section (or a light beam having a predetermined light intensity distribution) via a light beam conversion element such as a diffractive optical element. The light beam of this predetermined cross section illuminates the incident surface of an optical integrator such as a fly-eye lens in a superimposed manner through a condensing optical system, and a secondary light source (for example, An annular or quadrupolar secondary light source) is formed. For example, when an excimer laser light source is used, in this type of conventional configuration, a speckle pattern is generated on the mask surface and the photosensitive substrate surface, which are the irradiated surface, due to the diffractive optical element.

In the present invention, for example, the diffractive optical element and the front focal position of the light-converging optical system are arranged at a predetermined distance along the optical axis. In this case, as described later with reference to FIGS. 7 and 8, when a light beam is obliquely incident on the diffractive optical element, the wavefront of ± 1 order light generated by the diffractive optical element and incident on the fly-eye lens is relatively generated. It tilts and a phase difference occurs according to the incident angle. As a result, different speckle patterns are formed on the mask for each incident angle, so that the speckle pattern distributions at each incident angle are superimposed on each other and spatially averaged, thereby substantially reducing interference noise on the mask. Is done.

The interference noise can also be reduced by moving the diffractive optical element back and forth along the optical axis and averaging the speckle pattern distribution over time. In addition, the distance to be set between the diffractive optical element and the front focal position of the condensing optical system is adjusted according to changes in illumination conditions, and a speckle pattern generated on the irradiated surface due to the diffractive optical element is adjusted. Can also be suppressed favorably. Generally,
Adjusting the diffractive optical element according to the change of the illumination condition in order to favorably suppress the speckle pattern generated on the irradiated surface, specifically, adjusting the movement along the optical axis, the direction orthogonal to the optical axis It is preferable to perform a movement adjustment along the axis, an inclination adjustment with respect to the optical axis, and the like.

As described above, in the illumination optical device of the present invention, the speckle pattern generated due to the diffractive optical element used in the modified illumination such as the annular illumination or the quadrupole illumination and the ordinary circular illumination is used. It can be substantially reduced. Therefore, in an exposure apparatus incorporating the illumination optical apparatus of the present invention, under favorable exposure conditions using deformed illumination in which the speckle pattern is substantially reduced,
Good projection exposure with high throughput can be performed. In addition, a good microdevice can be manufactured with high throughput and high resolution by using modified illumination in which the speckle pattern is substantially reduced.

An embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram schematically illustrating a configuration of an exposure apparatus including an illumination optical device according to an embodiment of the present invention.
In FIG. 1, the Z axis is along the normal direction of the wafer W as a photosensitive substrate, the Y axis is in the direction parallel to the plane of FIG. 1 in the wafer plane, and the Z axis is perpendicular to the plane of FIG. 1 in the wafer plane. The X axis is set in each direction. In FIG. 1,
The illumination optical device is set to perform annular illumination.

The exposure apparatus shown in FIG. 1 uses, for example, 248 nm (Kr) as a light source 1 for supplying exposure light (illumination light).
F) or an excimer laser light source for supplying light having a wavelength of 193 nm (ArF). A substantially parallel light beam emitted from the light source 1 along the Z direction has a rectangular cross section elongated in the X direction, and enters a beam expander 2 including a pair of lenses 2a and 2b. Each of the lenses 2a and 2b is in the plane of FIG. 1 (in the YZ plane).
Has a negative refractive power and a positive refractive power, respectively. Therefore, the light beam incident on the beam expander 2 is enlarged in the plane of FIG. 1 and shaped into a light beam having a predetermined rectangular cross section.

The substantially parallel light beam passing through the beam expander 2 as a shaping optical system is deflected in the Y direction by the bending mirror 3 and then enters the micro fly's eye 4. The micro fly's eye 4 is an optical element composed of a large number of regular hexagonal microlenses having positive refracting power, which are arranged vertically and horizontally and densely. The micro fly's eye 4 is formed, for example, by etching a parallel flat glass plate to form a group of microlenses. In FIG. 1,
For clarity of the drawing, the number of microlenses constituting the micro fly's eye 4 is shown to be much smaller than the actual number.

Therefore, the light beam incident on the micro fly's eye 4 is two-dimensionally divided by a large number of minute lenses, and one light source (condensing point) is formed on the rear focal plane of each minute lens. Light beams from a large number of light sources formed on the rear focal plane of the micro fly's eye 4 become divergent light beams each having a regular hexagonal cross section, and are incident on an afocal zoom lens 5 as a first variable power optical system. I do. As described above, the micro fly's eye 4 constitutes a first light beam conversion element for converting the light beam from the light source 1 into a light beam having a predetermined cross section (or a light beam having a predetermined light intensity distribution).

The micro fly's eye 4 is configured to be insertable into and removable from the illumination optical path, and is configured to be switchable with the micro fly's eye 4a for quadrupole illumination. Further, the afocal zoom lens 5 is configured so that the magnification can be continuously changed within a predetermined range while maintaining an afocal system (a non-focus optical system).
Here, the retracting of the micro fly's eye 4 from the illumination optical path and the switching to the micro fly's eye 4a for quadrupole illumination are performed by the first drive system 22 that operates based on a command from the control system 21. The magnification change of the afocal zoom lens 5 is performed by the second drive system 23 that operates based on a command from the control system 21.

The light beam having passed through the afocal zoom lens 5 enters a diffractive optical element (DOE) 6 for annular illumination. At this time, the divergent light flux from each light source formed on the rear focal plane of the micro fly's eye 4 converges (collects) near the diffraction surface of the diffractive optical element 6 while maintaining a regular hexagonal cross section. . That is, the afocal zoom lens 5
Connects the back focal plane of the micro fly's eye 4 and the vicinity of the diffractive surface of the diffractive optical element 6 in an optically conjugate manner. Then, the numerical aperture of the light beam condensed near the diffractive surface of the diffractive optical element 6 changes depending on the magnification of the afocal zoom lens 5.

The diffractive optical element 6 is formed, for example, by forming a step having a pitch on the order of the wavelength of exposure light (illumination light) on a glass substrate, and has a function of diffracting an incident beam to a desired angle. Specifically, as shown in FIG. 2A, the diffractive optical element 6 for annular illumination converts a thin light beam perpendicularly incident parallel to the optical axis AX into a ring-shaped light beam centered on the optical axis AX. Convert to Therefore, as shown in FIG. 2B, when a thick parallel light beam is perpendicularly incident on the diffractive optical element 6, the rear focal position of the lens 31 disposed behind the diffractive optical element 6 also has a ring shape. Is formed.

That is, the diffractive optical element 6 forms a ring-shaped light intensity distribution in the far field (or Fraunhofer diffraction region). Here, as shown in FIG. 2C, when a thick parallel light beam incident on the diffractive optical element 6 is inclined with respect to the optical axis AX, a ring-shaped image formed at the rear focal position of the lens 31 moves. I do. That is, when the thick parallel light beam incident on the diffractive optical element 6 is tilted along a predetermined plane, the ring-shaped image 33 formed at the rear focal position of the lens 31 does not change its size. The center moves along a predetermined plane in a direction opposite to the direction in which the light beam is inclined.

As described above, the divergent light flux from each light source formed on the rear focal plane of the micro fly's eye 4 converges near the diffractive surface of the diffractive optical element 6 while maintaining a regular hexagonal cross section. I do. In other words, light beams having various angle components are incident on the diffractive optical element 6, and the incident angle is defined by the light beam range of a regular hexagonal pyramid. Therefore, as shown in FIG. 3A, the light is incident at the maximum angle corresponding to each ridge line of the regular hexagonal pyramid-shaped light beam centering on the ring-shaped image 40 formed by the light beam vertically incident on the diffractive optical element 6. The light beams thus formed form ring-shaped images 41 to 46 at the rear focal position of the lens 31. actually,
Since an infinite number of light beams having a large number of angular components defined by the regular hexagonal pyramid-shaped light beam range enter the diffractive optical element 6, an infinite number of ring-shaped images are superimposed on the rear focal position of the lens 31. As a whole, an annular illumination field as shown in FIG. 3B is formed.

As described above, the diffractive optical element 6 converts the light beam from the afocal zoom lens 5 as the first variable power optical system into a light beam having a predetermined cross section (or a light beam having a predetermined light intensity distribution). This constitutes a two-beam conversion element. The diffractive optical element 6 is configured to be freely inserted into and removed from the illumination optical path, and is configured to be switchable between a diffractive optical element 6a for quadrupole illumination and a diffractive optical element 6b for normal circular illumination. Here, switching between the diffractive optical element 6 for annular illumination, the diffractive optical element 6a for quadrupole illumination, and the diffractive optical element 6b for normal circular illumination operates based on a command from the control system 21. This is performed by the third drive system 24.

Referring again to FIG. 1, the light beam having passed through the diffractive optical element 6 is transmitted to a zoom lens 7 as a second variable power optical system.
Incident on. Here, the zoom lens 7 has the same operation as the lens 31 shown in FIG. In the vicinity of the rear focal plane of the zoom lens 7, an entrance surface of a fly-eye lens 8 as an optical integrator is positioned. Therefore, the light beam having passed through the diffractive optical element 6 is applied to the rear focal plane of the zoom lens 7 and, consequently, to the entrance surface of the fly-eye lens 8 in a ring-like shape centered on the optical axis AX as shown in FIG. To form the Teruno field. The size (outside diameter: diameter) of the annular illumination field changes depending on the focal length of the zoom lens 7. As described above, the zoom lens 7 connects the diffractive optical element 6 and the incident surface of the fly-eye lens 8 substantially in a Fourier transform relationship. The change in the focal length of the zoom lens 7 is performed by the fourth drive system 25 that operates based on a command from the control system 21.

The fly-eye lens 8 is constituted by arranging a large number of lens elements having a positive refractive power vertically and horizontally and densely. Each lens element constituting the fly-eye lens 8 has a rectangular cross-section similar to the shape of the illumination field to be formed on the mask (and the shape of the exposure area to be formed on the wafer). The entrance side surface of each lens element constituting the fly-eye lens 8 is formed in a spherical shape with a convex surface facing the incident side, and the exit side surface is formed in a spherical shape with a convex surface facing the exit side. .

Therefore, the light beam incident on the fly-eye lens 8 is two-dimensionally divided by a large number of lens elements, and a light source is formed on the rear focal plane of each lens element on which the light beam has entered. Thus, on the rear focal plane of the fly-eye lens 8, as shown in FIG.
A ring-shaped surface light source (hereinafter, referred to as “secondary light source”) having substantially the same light intensity distribution as the illumination field formed by the light beam incident on the fly-eye lens 8 is formed. The fly-eye lens 8 receives the light beam from the zoom lens 7 as the second variable power optical system, and receives the mask M and the wafer W, which are the irradiated surfaces.
The optical integrator for illuminating the light uniformly is configured. A light beam from the annular secondary light source formed on the rear focal plane of the fly-eye lens 8 enters an aperture stop 9 arranged near the light source. The aperture stop 9 is supported on a turret (rotary plate: not shown in FIG. 1) rotatable around a predetermined axis parallel to the optical axis AX.

FIG. 4 is a diagram schematically showing a configuration of a turret in which a plurality of aperture stops are arranged in a circumferential shape. As shown in FIG. 4, the turret substrate 400 is provided with eight aperture stops having light transmission areas indicated by oblique lines in the figure along the circumferential direction. The turret substrate 400 is configured to be rotatable around an axis passing through the center point O and parallel to the optical axis AX. Therefore, by rotating the turret substrate 400, one aperture stop selected from eight aperture stops can be positioned in the illumination optical path. The rotation of the turret substrate 400 is performed by the fifth drive system 26 that operates based on a command from the control system 21.

On the turret substrate 400, three annular aperture stops 401, 403 and 405 having different annular ratios are formed. Here, the annular aperture stop 401 is r11
It has an annular transmission region having an annular ratio of / r21.
The annular aperture stop 403 has an annular transmission region having an annular ratio of r12 / r22. The annular aperture stop 405 is
It has an annular transmission region having an annular ratio of r13 / r21.

The turret substrate 400 has three quadrupole aperture stops 402, 404 and 40 with different ring ratios.
6 are formed. Here, the four-pole aperture stop 402 is
It has four eccentric circular transmissive regions in an annular region having an annular ratio of r11 / r21. 4-pole aperture stop 4
No. 04 has four eccentric circular transmission regions in an annular region having an annular ratio of r12 / r22. The quadrupole aperture stop 406 has four eccentric circular transmission areas in an annular area having an annular ratio of r13 / r21.

The turret substrate 400 has two circular aperture stops 407 and 4 having different sizes (diameters).
08 is formed. Here, the circular aperture stop 407 has a circular transmission area having a size of 2r22, and the circular aperture stop 408 has a circular transmission area having a size of 2r21.

Therefore, three annular aperture stops 401,
By selecting one of the annular aperture stops 403 and 405 and positioning it in the illumination optical path, the annular luminous flux having three different outer diameters and annular zone ratios is accurately limited (defined).
Thus, three types of annular illumination having different σ values and annular ratios can be performed. Also, three quadrupole aperture stops 402 and 404
And 406, one of the four-pole aperture stops is selected and positioned in the illumination optical path to accurately limit four eccentric light fluxes having three different outer diameters and annular ratios, and σ
It is possible to perform three types of quadrupole illumination having different values and ring zone ratios. Further, by selecting one of the two circular aperture stops 407 and 408 and positioning it in the illumination optical path, two types of normal circular illumination having different σ values can be performed.

In FIG. 1, an annular secondary light source is formed on the rear focal plane of the fly-eye lens 8, so that the aperture stop 9 is one selected from three annular aperture stops 401, 403 and 405. An annular aperture stop is used. However, the configuration of the turret shown in FIG.
The type and number of the aperture stops to be arranged are not limited to this. In addition, without being limited to the turret type aperture stop, an aperture stop capable of appropriately changing the size and shape of the light transmission region may be fixedly mounted in the illumination optical path. Further, instead of the two circular aperture stops 407 and 408, an iris diaphragm capable of continuously changing the circular aperture diameter can be provided.

Light from a secondary light source through an aperture stop 9 having a ring-shaped opening (light transmitting portion) is subjected to a condensing action of a condenser optical system 10 as a light guiding optical system, and then is subjected to a predetermined light. The mask M on which the pattern is formed is uniformly illuminated in a superimposed manner. The light flux transmitted through the pattern of the mask M forms an image of the mask pattern on the wafer W as a photosensitive substrate via the projection optical system PL. Thus, the wafer W is positioned on a plane (XY plane) orthogonal to the optical axis AX of the projection optical system PL.
Is subjected to batch exposure or scan exposure while the two-dimensional drive control is performed, whereby the pattern of the mask M is sequentially exposed on each exposure region of the wafer W.

In the batch exposure, a so-called step
According to the AND-repeat method, the mask pattern is collectively exposed to each exposure region of the wafer. In this case, the shape of the illumination area on the mask M is a rectangular shape close to a square, and the cross-sectional shape of each lens element of the fly-eye lens 8 is also a rectangular shape close to a square. On the other hand, in scan exposure, according to a so-called step-and-scan method, a mask pattern is scanned and exposed on each exposure region of a wafer while the mask and wafer are relatively moved with respect to a projection optical system. In this case, the shape of the illumination area on the mask M is such that the ratio of the short side to the long side is, for example, 1: 3.
, And the cross-sectional shape of each lens element of the fly-eye lens 8 is also similar to this.

In this embodiment, by changing the magnification of the afocal zoom lens 5, the size (outer diameter φo) and the shape (ring ratio: inner diameter φ) of the annular secondary light source are changed.
i / outer diameter φo) can be changed together. Also,
By changing the focal length of the zoom lens 7, the outer diameter of the secondary light source having a ring shape can be changed without changing the ring ratio. Furthermore, by appropriately changing the magnification of the afocal zoom lens 5 and the focal length of the zoom lens 7, only the ring ratio can be changed without changing the outer diameter of the ring-shaped secondary light source. Thus, when using the diffractive optical element 6 for annular illumination,
An annular secondary light source can be formed based on the light beam from the light source 1 with almost no light amount loss, and as a result, the light amount loss in the aperture stop 9 for limiting the light beam from the secondary light source can be favorably suppressed. Band illumination can be performed.

As described above, the micro fly eye 4
Are configured to be insertable into and removable from the illumination optical path, and to be switchable with the micro fly's eye 4a for quadrupole illumination. The diffractive optical element 6 is configured so as to be freely inserted into and removed from the illumination optical path, and is a diffractive optical element 6 for quadrupole illumination.
a and a diffractive optical element 6b for ordinary circular illumination. Hereinafter, quadrupole illumination obtained by setting the micro fly's eye 4a in the illumination light path instead of the micro fly's eye 4 and setting the diffractive optical element 6a in the illumination light path instead of the diffractive optical element 6 will be described. .

The micro fly's eye 4a is composed of a large number of square-shaped microlenses having positive refracting power arranged vertically and horizontally and densely. Therefore, although a large number of light sources are formed on the rear focal plane of the micro fly's eye 4a, the luminous fluxes from the respective light sources enter the afocal zoom lens 5 as divergent luminous fluxes each having a square cross section. The luminous flux through the afocal zoom lens 5 is 4
The light enters the diffractive optical element 6a for polar illumination. At this time, the divergent luminous flux from each light source image formed on the rear focal plane of the micro fly's eye 4a is maintained while maintaining a square cross section.
It converges (condenses) near the diffractive surface of the diffractive optical element 6a.

The diffractive optical element 6a for quadrupole illumination is shown in FIG.
As shown in (a), a thin light beam perpendicularly incident parallel to the optical axis AX is converted into four light beams radiating radially according to one predetermined exit angle. In other words, a thin light beam that is perpendicularly incident along the optical axis AX is diffracted at equal angles around the optical axis AX along four specific directions, resulting in four thin light beams. More specifically, a thin light beam that is perpendicularly incident on the diffractive optical element 6a is converted into four light beams, and the square connecting the passing points of the four light beams passing through the rear surface parallel to the diffractive optical element 6a is a square. The center of the square exists on the axis of incidence on the diffractive optical element 6a.

Therefore, as shown in FIG. 5B, when a thick parallel light beam is perpendicularly incident on the diffractive optical element 6a, the rear focal position of the lens 51 disposed behind the diffractive optical element 6a is Again four point images (point-like light source images)
52 are formed. Here, as shown in FIG.
When a thick parallel light beam incident on the diffractive optical element 6a is inclined with respect to the optical axis AX, four point images formed at the rear focal position of the lens 51 move. That is, the diffractive optical element 6a
When the thick parallel light beam incident on the lens 51 is inclined along a predetermined plane, the four point images 53 formed at the rear focal position of the lens 51
Moves along a predetermined plane in a direction opposite to the direction in which the light flux is inclined.

As described above, the micro fly eye 4a
The divergent light beams from the respective light sources formed on the rear focal plane converge on the vicinity of the diffraction surface of the diffractive optical element 6a while maintaining a square cross section. In other words, a light beam having a large number of angle components is incident on the diffractive optical element 6a, and the incident angle is defined by a light beam range of a regular quadrangular pyramid. That is, an infinite number of luminous fluxes having a large number of angle components defined by the luminous flux range of the regular quadrangular pyramid shape are diffractive optical elements 6a
Therefore, an infinite number of point images are superimposed on the rear focal position of the lens 51, and a quadrupole image as shown in FIG. 6A is formed as a whole. Therefore, the light beam having passed through the diffractive optical element 6a forms a quadrupole illumination field on the rear focal plane of the zoom lens 7, and thus on the incident plane of the fly-eye lens 8. As a result, as shown in FIG. 6B, a quadrupole secondary light source identical to the illumination field formed on the incident surface is also formed on the rear focal plane of the fly-eye lens 8.

The switching from the annular aperture stop 9 to the aperture stop 9a is performed corresponding to the switching from the micro fly's eye 4 to the micro fly's eye 4a and the switching from the diffractive optical element 6 to the diffractive optical element 6a. . The aperture stop 9a includes three quadrupole aperture stops 402, 404 and 4
6 is one quadrupole aperture stop selected from the reference numeral 06. As described above, when the micro fly's eye 4a for quadrupole illumination and the diffractive optical element 6a are used, a quadrupole secondary light source can be formed with little loss of light amount based on the light beam from the light source 1, As a result, the light amount loss in the aperture stop 9a for limiting the light flux from the secondary light source
Polar lighting can be provided.

As shown in FIG. 6B, the size and shape of the quadrupole secondary light source can be defined in the same manner as the annular secondary light source. By changing the magnification of the afocal zoom lens 5 as in the case of the annular illumination, both the outer diameter (φo) and the annular ratio (φi / φo) of the quadrupolar secondary light source are changed. be able to.
Further, by changing the focal length of the zoom lens 7, the outer diameter of the quadrupole secondary light source can be changed without changing the annular ratio. Further, by appropriately changing the magnification of the afocal zoom lens 5 and the focal length of the zoom lens 7, only the annular ratio can be changed without changing the outer diameter of the quadrupole secondary light source. .

Next, the micro fly eyes 4 and 4a
Are retracted from the illumination optical path, and a diffractive optical element 6b for circular illumination is used instead of the diffractive optical element 6 or 6a.
Is set in the illumination optical path, a normal circular illumination obtained by setting the illumination in the illumination optical path will be described. In this case, a light beam having a rectangular cross section enters the afocal zoom lens 5 along the optical axis AX. The light beam incident on the afocal zoom lens 5 is enlarged or reduced in accordance with the magnification, emitted from the afocal zoom lens 5 along the optical axis AX as a light beam having a rectangular cross section, and transmitted to the diffractive optical element 6b. Incident.

Here, the diffractive optical element 6b for circular illumination
Has a function of converting an incident rectangular light beam into a circular light beam. Accordingly, the circular light beam formed by the diffractive optical element 6b forms a circular illumination field centered on the optical axis AX on the incident surface of the fly-eye lens 8 via the zoom lens 7. As a result, a circular secondary light source centered on the optical axis AX is also formed on the rear focal plane of the fly-eye lens 8. In this case, by changing the focal length of the zoom lens 7, the outer diameter of the circular secondary light source can be appropriately changed.

Incidentally, in correspondence with the retreat of the micro fly's eyes 4 and 4a from the illumination optical path and the setting of the diffractive optical element 6b for circular illumination to the illumination optical path, the annular aperture stop 9 or the quadrupole aperture stop 9a is used. Switching to the circular aperture stop 9b is performed. The circular aperture stop 9b includes two circular aperture stops 4
One circular aperture stop selected from 07 and 408, which has an opening having a size corresponding to a circular secondary light source. As described above, the micro fly's eyes 4 and 4a are retracted from the illumination optical path to make the diffractive optical element 6b for circular illumination.
Is used, a circular secondary light source is formed based on the light flux from the light source 1 with almost no light quantity loss, and the light quantity loss in the aperture stop that restricts the light flux from the secondary light source is satisfactorily suppressed while the normal circular illumination is performed. It can be performed.

In this embodiment, the mask M which is the surface to be irradiated is
Above (and thus on the wafer W), the diffractive optical element 6 (6
a, 6b) to substantially reduce the speckle pattern generated due to the diffractive optical element 6 (6a, 6b).
Are arranged at a predetermined distance from the front focal position of the zoom lens 7 along the optical axis direction. Hereinafter, the relationship between the arrangement of the diffractive optical elements 6 (6a, 6b) and the reduction of speckle patterns (interference noise) will be described.

FIG. 7 is a diagram for explaining the reason why a speckle pattern is generated on the irradiated surface when the diffractive surface of the diffractive optical element 6 is arranged at the front focal position of the zoom lens 7. As shown in FIG. 7, when the diffractive surface of the diffractive optical element 6 is disposed at the front focal position of the zoom lens 7, when a light beam is perpendicularly incident on the diffractive optical element 6, a point on the diffractive optical element 6 starts at one point. Generated ± 1st order light (shown by solid line in the figure)
Travel at symmetric angles with respect to the optical axis AX, and fly-eye lenses 8 at symmetric positions with respect to the optical axis AX, respectively.
And at the same position within each lens element 8a. These rays merge again on the mask M and interfere. Thus, a speckle pattern is generated on the mask M due to the diffractive optical element 6.

Although the light from the excimer laser light source 1 has a divergence angle α, the occurrence of the speckle pattern is not reduced in this case as well. That is, when a light ray is obliquely incident on the diffractive optical element 6 at the maximum incident angle α according to the divergence angle α of the light source 1, ± first-order light (shown by a broken line in the drawing) generated by the diffractive optical element 6 is asymmetric with respect to the optical axis AX. The incident position on the lens element 8a shifts from the incident position in the case of normal incidence. However, since the diffractive surface of the diffractive optical element 6 is located at the front focal position of the zoom lens 7, the wavefront WS1 for vertical incidence indicated by a solid line in the drawing and the wavefront WS2 for oblique incidence indicated by a broken line in the drawing are referred to. As can be seen, no wavefront tilt occurs. As described above, even when the incident light beam to the diffractive optical element 6 has an incident angle, no phase difference occurs. Therefore, even if the illumination light enters the diffractive optical element 6 at various incident angles, each angle component is Form the same speckle pattern on the mask M. In other words, no averaging of the speckle pattern by the divergence angle α of the light source 1 occurs.

FIG. 8 is a diagram schematically illustrating the operation of the present invention for reducing the speckle pattern generated on the irradiated surface in the present embodiment. As shown in FIG. 8, in the present embodiment, the diffractive surface of the diffractive optical element 6 is disposed closer to the light source by a distance d than the front focal position of the zoom lens 7. Therefore, when the light beam is obliquely incident on the diffractive optical element 6 at the maximum incident angle α, the wavefront of the ± 1st-order light (shown by a broken line in the drawing) generated by the diffractive optical element 6 and incident on the fly-eye lens 8 is relatively It can be seen that there is a tilt and a phase difference occurs according to the incident angle α. This phenomenon is understood from the fact that the angle of the light beam incident on the fly-eye lens 8 is determined at a position passing through the front focal plane (shown by a broken line in the drawing) 7a of the zoom lens 7. If this phenomenon is used, a speckle pattern that differs for each incident angle is formed on the mask M. That is, the speckle pattern distributions at each incident angle are superimposed on each other and averaged, and the interference noise on the mask M is substantially reduced.

The generated phase difference increases as the distance d increases, assuming that the divergence angle α of the light source 1 is constant. Further, the generated phase difference becomes larger as the lens element 8a in the corresponding fly-eye lens 8 is farther from the optical axis AX. Here, the minimum position (minimum distance from the optical axis AX) of the lens element 8a is determined to a certain value for each illumination mode. Therefore, if the divergence angle α of the light source 1 and the minimum position of the lens element 8a are determined within the range of the illumination condition to be used, the phase difference of the ± primary light with respect to the lens element 8a at the minimum position is equal to or greater than the wavelength. It is desirable to adjust the distance d.

In the above description, the diffractive surface of the diffractive optical element 6 is arranged closer to the light source than the front focal position of the zoom lens 7, but may be arranged closer to the mask than the front focal position of the zoom lens 7. , A similar speckle pattern reduction effect can be obtained. Afocal zoom lens 5
By setting such that the position where the light beam is condensed and the diffraction surface of the diffractive optical element 6 are separated by a predetermined distance along the optical axis AX, the same speckle pattern reduction effect can be obtained. In this case, the rear focal position of the rear lens group of the afocal zoom lens 5 and the diffractive surface of the diffractive optical element 6 are arranged with a predetermined distance therebetween.

In the above description, the interference noise is reduced by superimposing the speckle pattern distributions at each incident angle and spatially averaging them, but the diffractive optical element 6 is moved along the optical axis AX. The interference noise can also be reduced by reciprocating and averaging the speckle pattern distribution over time. In this case, for example, a third drive system 24 can be used as a drive unit for reciprocating the diffractive optical element 6 along the optical axis AX.

Further, as described above, the required distance to be set between the diffractive surface of the diffractive optical element 6 and the front focal position of the zoom lens 7 changes according to the change in the illumination condition. Therefore, it is preferable to adjust the diffractive optical element 6 according to the change of the illumination condition in order to favorably suppress the speckle pattern generated on the mask M. In particular,
Movement adjustment of the diffractive optical element 6 along the optical axis AX, optical axis AX
It is preferable to adjust the movement of the diffractive optical element 6 along a direction perpendicular to the direction of the arrow and to adjust the inclination of the diffractive optical element 6 with respect to the optical axis AX.

In order to adjust the distance to be set between the diffractive surface of the diffractive optical element 6 and the front focal position of the zoom lens 7, the diffractive optical element 6 is moved using, for example, the third drive system 24. Alternatively, the front focal position of the zoom lens 7 may be changed using the fourth drive system 25, for example. To adjust the distance to be set between the diffractive surface of the diffractive optical element 6 and the light condensing position of the afocal zoom lens 5, the diffractive optical element 6 is moved using, for example, the third drive system 24. Alternatively, for example, the second drive system 23
The focus position by the afocal zoom lens 5 may be changed by using.

Hereinafter, the switching operation of the illumination and the like in this embodiment will be briefly described. First, information relating to various masks to be sequentially exposed according to the step-and-repeat method or the step-and-scan method is input to the control system 21 via input means 20 such as a keyboard. The control system 21 stores information such as the optimum line width (resolution) and depth of focus for various masks in an internal memory unit, and responds to an input from the input unit 20 to the first drive system 22 to the first drive system 22. 5 supplies an appropriate control signal to the drive system 26.

That is, when zonal illumination is performed under the optimum resolution and depth of focus, the first drive system 22 is controlled by the control system 21.
The micro fly's eye 4 for annular illumination is positioned in the illumination optical path based on a command from the
4 positions the diffractive optical element 6 for annular illumination in the illumination optical path based on a command from the control system 21. Then, in order to obtain a ring-shaped secondary light source having a desired size (outer diameter) and shape (ring zone ratio) on the rear focal plane of the fly-eye lens 8, the second drive system 23 is controlled by the control system 21. The magnification of the afocal zoom lens 5 is set based on the command
The fourth drive system 25 sets the focal length of the zoom lens 7 based on a command from the control system 21. In addition, in order to limit the annular light source in a state where the light quantity loss is suppressed well,
The fifth drive system 26 rotates the turret based on a command from the control system 21 to position a desired annular aperture stop in the illumination optical path. Further, on the mask M (and thus the wafer W
The third drive system 24 moves the diffractive optical element 6 by a predetermined distance along the optical axis AX based on a command from the control system 21 in order to favorably suppress the speckle pattern generated in (1).

In this manner, a secondary light source having a ring shape can be formed with little loss of light amount based on the light beam from the light source 1, and as a result, almost all light amount is lost in the aperture stop for limiting the light beam from the secondary light source. It is possible to perform annular illumination without the need. Further, a speckle pattern generated due to the diffractive optical element 6 on the mask M (and thus on the wafer W) can be favorably suppressed.

Further, if necessary, the magnification of the afocal zoom lens 5 is changed by the second drive system 23, and the focal length of the zoom lens 7 is changed by the fourth drive system 25, whereby the fly-eye lens 8 The size and annular ratio of the annular secondary light source formed on the rear focal plane can be appropriately changed. In this case, the turret rotates in accordance with the change in the size of the annular secondary light source and the annular ratio, and an annular aperture stop having a desired size and annular ratio is selected and positioned in the illumination optical path. You. Further, if necessary, the diffractive optical element 6 is moved by a predetermined distance along the optical axis AX. In this way, the annular secondary light source is formed while the speckle pattern generated due to the diffractive optical element 6 on the mask M is satisfactorily suppressed, with little loss of light amount in the formation and limitation of the annular secondary light source. A variety of annular illumination can be performed by appropriately changing the size and the annular ratio.

When quadrupole illumination is performed under the optimum resolution and depth of focus, the first drive system 22 operates based on a command from the control system 21 to provide a micro fly eye 4a for quadrupole illumination.
Is positioned in the illumination optical path, and the third drive system 24
Positions the diffractive optical element 6a for quadrupole illumination in the illumination optical path based on a command from the control system 21. Then, in order to obtain a quadrupole secondary light source having a desired size (outer diameter) and shape (ring zone ratio) on the rear focal plane of the fly-eye lens 8, the second drive system 23 is controlled by the control system 21. The fourth drive system 25 sets the focal length of the zoom lens 7 based on a command from the control system 21 based on a command from the control system 21. Further, in order to limit the quadrupole secondary light source in a state in which the light quantity loss is suppressed well, the fifth drive system 26 rotates the turret based on a command from the control system 21 to provide a desired 4-pole aperture stop. Are positioned in the illumination light path. Further, the third drive system 24 moves the diffractive optical element 6a along the optical axis AX based on a command from the control system 21 in order to favorably suppress a speckle pattern generated on the mask M (and thus on the wafer W). Move by a predetermined distance.

In this way, a quadrupole secondary light source can be formed with almost no light quantity loss based on the light flux from the light source 1, and as a result, the light loss at the aperture stop for limiting the light flux from the secondary light source can be reduced. It is possible to perform quadrupole illumination with good suppression. Further, a speckle pattern generated due to the diffractive optical element 6 on the mask M (and thus on the wafer W) can be favorably suppressed.

Further, if necessary, the magnification of the afocal zoom lens 5 is changed by the second drive system 23 or the focal length of the zoom lens 7 is changed by the fourth drive system 25 to thereby provide the fly-eye lens 8. The size and the annular ratio of the quadrupolar secondary light source formed on the rear focal plane can be changed as appropriate. In this case, the turret rotates in accordance with the change in the size and the orbital ratio of the quadrupolar secondary light source, and a quadrupole aperture stop having the desired size and the orbital ratio is selected and positioned in the illumination optical path. Is done. In addition, if necessary, the diffractive optical element 6a is moved by a predetermined distance along the optical axis AX. Thus, while suppressing the light quantity loss in the formation and limitation of the quadrupole secondary light source,
Performing various quadrupole illuminations by appropriately changing the size and ring ratio of the quadrupolar secondary light source while favorably suppressing the speckle pattern generated due to the diffractive optical element 6a on the mask M Can be.

When ordinary circular illumination is performed under the optimum resolution and depth of focus, the first drive system 22 retracts the micro fly's eye 4 or 4a from the illumination optical path based on a command from the control system 21. . Also, the third drive system 24
Positions the diffractive optical element 6b for normal circular illumination in the illumination optical path based on a command from the control system 21. Then, in order to obtain a circular secondary light source having a desired size (outer diameter) on the rear focal plane of the fly-eye lens 8,
The second drive system 23 sets the magnification of the afocal zoom lens 5 based on a command from the control system 21,
5 sets the focal length of the zoom lens 7 based on a command from the control system 21.

Further, in order to limit the circular secondary light source with the light quantity loss being suppressed well, the fifth drive system 26 rotates the turret based on a command from the control system 21 to rotate the turret to a desired circular aperture. The diaphragm is positioned in the illumination light path. In addition,
When an iris diaphragm capable of continuously changing the circular aperture diameter is used, the fifth drive system 26 sets the aperture diameter of the iris diaphragm based on a command from the control system 21. further,
In order to favorably suppress a speckle pattern generated on the mask M (hence, on the wafer W), the third driving system 2
4 is a diffractive optical element 6b based on a command from the control system 21.
Is moved by a predetermined distance along the optical axis AX. In this way, a circular secondary light source can be formed with almost no loss of light amount based on the light beam from the light source 1, and as a result, the light amount loss can be favorably suppressed in the aperture stop that restricts the light beam from the secondary light source. Usually circular illumination can be performed. Further, the speckle pattern generated on the mask M (and thus on the wafer W) due to the diffractive optical element 6b can be favorably suppressed.

Further, if necessary, the focal length of the zoom lens 7 is changed by the fourth drive system 25, so that the size of the circular secondary light source formed on the rear focal plane of the fly-eye lens 8 is increased. Can be appropriately changed. In this case, the turret rotates according to the change in the size of the circular secondary light source, and a circular aperture stop having an opening of a desired size is selected and positioned in the illumination light path. In addition, if necessary, the diffractive optical element 6b is moved by a predetermined distance along the optical axis AX. In this way, the σ value is appropriately changed while the spectroscopic pattern generated due to the diffractive optical element 6a on the mask M is favorably suppressed while the light amount loss is favorably suppressed in the formation and limitation of the circular secondary light source. Thus, a variety of normal circular illuminations can be performed.

In the exposure apparatus according to the above-described embodiment, the mask is illuminated by the illumination optical device (illumination step), and the transfer pattern formed on the mask is scanned and exposed on the photosensitive substrate using the projection optical system ( By performing the exposure step, a micro device (semiconductor element, imaging element, liquid crystal display element, thin film magnetic head, etc.) can be manufactured. Hereinafter, an example of a method for obtaining a semiconductor device as a micro device by forming a predetermined circuit pattern on a wafer or the like as a photosensitive substrate using the exposure apparatus of the present embodiment shown in FIG. This will be described with reference to a flowchart.

First, in step 301 of FIG.
A metal film is deposited on the wafers of the lot. In the next step 302, a photoresist is applied on the metal film on the l lot of wafers. Then, step 303
1, an image of the pattern on the mask is sequentially exposed and transferred to each shot area on the wafer of the lot through the projection optical system (projection optical module) using the exposure apparatus shown in FIG. Then, in step 304,
After the development of the photoresist on the wafer of the lot is performed, in step 305, the circuit pattern corresponding to the pattern on the mask is etched by performing etching on the wafer of the lot using the resist pattern as a mask. It is formed in each shot area on each wafer.
Thereafter, a device such as a semiconductor element is manufactured by forming a circuit pattern of an upper layer and the like.
According to the above-described semiconductor device manufacturing method, a semiconductor device having an extremely fine circuit pattern can be obtained with good throughput.

In the exposure apparatus shown in FIG. 1, a liquid crystal display element as a micro device can be obtained by forming a predetermined pattern (circuit pattern, electrode pattern, etc.) on a plate (glass substrate). Less than,
An example of the technique at this time will be described with reference to the flowchart in FIG. In FIG. 10, in a pattern forming step 401, a so-called photolithography step of transferring and exposing a mask pattern onto a photosensitive substrate (a glass substrate coated with a resist) using the exposure apparatus of each embodiment is executed. By this photolithography process, a predetermined pattern including a large number of electrodes and the like is formed on the photosensitive substrate. Thereafter, the exposed substrate is subjected to various processes such as a developing process, an etching process, and a reticle peeling process, whereby a predetermined pattern is formed on the substrate, and the process proceeds to the next color filter forming process 402.

Next, in the color filter forming step 402, three colors corresponding to R (Red), G (Green) and B (Blue)
Many sets of dots are arranged in a matrix,
Alternatively, a color filter in which a plurality of sets of three stripe filters of R, G, and B are arranged in the horizontal scanning line direction is formed. Then, after the color filter forming step 402, a cell assembling step 403 is performed. In the cell assembly step 403, a liquid crystal panel (liquid crystal cell) is assembled using the substrate having the predetermined pattern obtained in the pattern formation step 401, the color filter obtained in the color filter formation step 402, and the like. In the cell assembling step 403, for example, a liquid crystal is injected between the substrate having the predetermined pattern obtained in the pattern forming step 401 and the color filter obtained in the color filter forming step 402, and a liquid crystal panel (liquid crystal cell) is formed. ) To manufacture.

Thereafter, in a module assembling step 404, components such as an electric circuit and a backlight for performing a display operation of the assembled liquid crystal panel (liquid crystal cell) are attached to complete a liquid crystal display element. According to the above-described method for manufacturing a liquid crystal display device, a liquid crystal display device having an extremely fine circuit pattern can be obtained with high throughput.

In the above embodiment, the micro fly's eye 4 or 4a is used as the light beam converting element, but a diffractive optical element can be used instead of the micro fly's eye. In this case, it is preferable to apply the present invention also to this diffractive optical element. That is, it is preferable to displace the diffractive optical element in the optical axis direction, reciprocate the diffractive optical element along the optical axis, or adjust the diffractive optical element according to changes in illumination conditions. . Incidentally, a detailed description of the diffractive optical element that can be used in the present invention is described in U.S. Pat.
It is disclosed in Japanese Patent Publication No. 0 and the like.

In the above-described embodiment, the micro fly's eye 4 (4a) or the diffractive optical element 6 (6a, 6b) as a light beam converting element is configured to be positioned in the illumination light path by, for example, a turret method. be able to. The micro fly's eye 4 (4a) and the diffractive optical element 6 described above may be
(6a, 6b) can be inserted and removed and switched.

Further, in the above-described embodiment, the shape of the micro lens constituting the micro fly's eye 4 is set to a regular hexagon. This is because a circular microlens cannot be arranged densely and causes a loss of light amount, and thus a regular hexagon is selected as a polygon close to a circle. However, the shape of each microlens constituting the micro fly's eye 4 is not limited to this, and other appropriate shapes including, for example, a rectangular shape can be used.

In the above-described embodiment, the aperture stop 9 for restricting the luminous flux of the secondary light source is arranged near the rear focal plane of the fly-eye lens 8. However, in some cases, a configuration in which the cross-sectional area of each lens element constituting the fly-eye lens is set to be sufficiently small to omit the arrangement of the aperture stop and not restrict the light flux of the secondary light source at all is also possible.

Further, in the above-described embodiment, the light from the secondary light source formed at the position of the aperture stop 9 is condensed by the condenser optical system 10 as the light guiding optical system to illuminate the mask M in a superimposed manner. However, between the condenser optical system 10 and the mask M, an illumination field stop (mask blind) and an image of the illumination field stop are masked by the mask M.
A relay optical system formed above may be arranged. In this case, the light guiding optical system includes a condenser optical system 10 and a relay optical system. The condenser optical system 10 collects light from a secondary light source formed at the position of the aperture stop 9 and superimposes the light. The illumination optical system illuminates the illumination field stop, and the relay optical system forms an image of the opening of the illumination field stop on the mask M.

In the above embodiment, the fly-eye lens 8 is formed by integrating a large number of lens elements. However, a micro fly-eye can be used instead of the fly-eye lens 8. The micro fly's eye is one in which a plurality of minute lens surfaces are provided in a matrix on a light transmitting substrate by a technique such as etching. In terms of forming a plurality of light source images, there is substantially no functional difference between the fly-eye lens and the micro fly-eye, but the size of the aperture of one element lens (micro lens) can be made extremely small. The micro fly's eye is advantageous in that the manufacturing cost can be greatly reduced and the thickness in the optical axis direction can be extremely reduced.

Further, in the above-described embodiment, the present invention has been described by taking as an example a projection exposure apparatus having an illumination optical device. However, the present invention is applied to a general illumination optical device for uniformly illuminating an irradiated surface other than a mask. It is clear that the invention can be applied.

In the above-described embodiment, since the exposure light having a wavelength of 180 nm or more, such as a KrF excimer laser (wavelength: 248 nm) or an ArF excimer laser (wavelength: 193 nm), is used as a light source, the diffractive optical element is, for example, It can be formed of quartz glass. When a wavelength of 200 nm or less is used as the exposure light, the diffractive optical element is made of fluorite, quartz glass doped with fluorine, quartz glass doped with fluorine and hydrogen, the structure determination temperature is 1200 K or less, and OH
Quartz glass having a base concentration of 1000 ppm or more, a structure determination temperature of 1200 K or less, and a hydrogen molecule concentration of 1 × 10 ¹⁷
molecules / cm ³ or more, quartz glass having a structure determination temperature of 1200 K or less and a chlorine concentration of 50 ppm or less, and a structure determination temperature of 1200 K or less and a hydrogen molecule concentration of 1 × 10 ¹⁷ molecules / cm ³ or more Preferably, it is formed of a material selected from the group of quartz glass having a chlorine concentration of 50 ppm or less.

A quartz glass having a structure determination temperature of 1200 K or less and an OH group concentration of 1000 ppm or more is disclosed in Japanese Patent No. 2770224 by the present applicant. Quartz glass having a molecular concentration of 1 × 10 ¹⁷ molecules / cm ³ or more, quartz glass having a structure determination temperature of 1200 K or less and a chlorine concentration of 50 ppm or less, and a structure determination temperature of 1200 K or less and a hydrogen molecule concentration of 1 × 10 ¹⁷ molecu
Quartz glass having a les / cm ³ or more and a chlorine concentration of 50 ppm or less is disclosed in Japanese Patent No. 2936138 by the present applicant.

[0089]

As described above, in the illumination optical device according to the present invention, the specs generated due to the diffractive optical element used in deformed illumination such as annular illumination and quadrupole illumination and ordinary circular illumination are used. The pattern can be substantially reduced. Therefore, in the exposure apparatus incorporating the illumination optical apparatus of the present invention, it is possible to perform good projection exposure with high throughput under favorable exposure conditions using deformed illumination with substantially reduced speckle patterns. it can. In addition, a good microdevice can be manufactured with high throughput and high resolution using the modified illumination in which the speckle pattern is substantially reduced.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a configuration of an exposure apparatus including an illumination optical device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating the operation of a diffractive optical element 6 for annular illumination.

FIG. 3 is a diagram illustrating an operation of a diffractive optical element 6 for annular illumination and showing an annular illumination field formed on an incident surface of a fly-eye lens 8;

FIG. 4 is a diagram schematically illustrating a configuration of a turret in which a plurality of aperture stops are arranged in a circumferential shape;

FIG. 5 is a diagram for explaining the function of a diffractive optical element for quadrupole illumination.

FIG. 6 is a diagram illustrating an operation of a diffractive optical element 6a for quadrupole illumination and showing a quadrupole illumination field formed on an incident surface of a fly-eye lens 8;

FIG. 7 is a diagram illustrating the reason why a speckle pattern is generated on a surface to be illuminated when the diffraction surface of the diffractive optical element 6 is arranged at the front focal position of the zoom lens 7.

FIG. 8 is a diagram schematically illustrating an operation of the present invention for reducing a speckle pattern generated on a surface to be irradiated in the present embodiment.

FIG. 9 is a flowchart of a method for obtaining a semiconductor device as a micro device.

FIG. 10 is a flowchart of a method for obtaining a liquid crystal display element as a micro device.

[Explanation of symbols]

 Reference Signs List 1 light source 4, 4a micro fly eye 5 afocal zoom lens 6, 6a, 6b diffractive optical element 7 zoom lens 8 fly eye lens 9, 9a, 9b aperture stop 10 condenser optical system M mask PL projection optical system W wafer 20 input means 21 control system 22-26 drive system

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 2H049 AA03 AA13 AA45 AA55 AA64 2H052 BA02 BA03 BA09 BA12 5F046 BA04 BA05 CA04 CA05 CB05 CB13 CB14 CB19 CB23

Claims (14)

[Claims] 1. An illumination optical device for illuminating a surface to be illuminated, comprising: a light source for supplying a light beam; and a light beam for converting the light beam from the light source device into a light beam having a predetermined cross section or a light beam having a predetermined light intensity distribution. A light beam converting element, a light collecting optical system for collecting light from the light beam converting element, and an optical integrator for receiving light from the light collecting optical system and uniformly illuminating the irradiated surface, A light guiding optical system for guiding a light beam from the optical integrator to the surface to be illuminated, wherein the light beam converting element and the front focal position of the light collecting optical system are arranged on the light receiving surface at the light beam converting element. An illumination optical device, wherein the illumination optical device is arranged at a predetermined distance so as to substantially reduce a speckle pattern generated due to the illumination. 2. An illumination optical device for illuminating a surface to be illuminated, comprising: a light source for supplying a light beam; and a light beam for converting the light beam from the light source device into a light beam having a predetermined cross section or a light beam having a predetermined light intensity distribution. A light beam converting element; and a light condensing optical system disposed between the light source means and the light beam converting element for condensing the light beam at a predetermined position. The light beam converting element and the light condensing optical system The predetermined position at which the light beam is condensed is arranged at a predetermined distance to substantially reduce a speckle pattern generated due to the light beam conversion element on the irradiated surface. An illumination optical device, comprising: 3. The illumination optical device according to claim 1, wherein the predetermined position where the light beam is collected by the light collecting optical system is a rear focal position of the light collecting optical system. 4. An illumination optical device for illuminating a surface to be illuminated, comprising: a light source for supplying a light beam; and a light beam for converting the light beam from the light source device into a light beam having a predetermined cross section or a light beam having a predetermined light intensity distribution. A light beam converting element, a light collecting optical system for collecting light from the light beam converting element, and an optical integrator for receiving light from the light collecting optical system and uniformly illuminating the irradiated surface, A light guiding optical system for guiding a light beam from the optical integrator to the surface to be irradiated, and the light beam for temporally averaging a speckle pattern generated by the light beam conversion element on the surface to be irradiated. A driving unit for reciprocating the conversion element along the optical axis. 5. A light source for supplying a light beam for illuminating a surface to be illuminated, and a light beam having a predetermined cross-section or a light beam from the light source arranged between the light source and the surface to be illuminated. A light beam conversion element for converting the light beam into a light beam having a predetermined light intensity distribution; and an adjusting unit for adjusting the light beam conversion element according to a change in illumination conditions on the irradiation surface. Illumination optics. 6. The apparatus according to claim 5, further comprising a front light condensing optical system disposed between said light source means and said light beam conversion element for condensing said light beam at a predetermined position. The illumination optical device according to claim 1. 7. The optical system according to claim 5, further comprising a rear light condensing optical system disposed between the light beam conversion element and the irradiated surface for condensing light from the light beam conversion element. 7. The illumination optical device according to 6. 8. The optical system according to claim 1, further comprising an optical integrator disposed in an optical path between the rear light condensing optical system and the irradiated surface to uniformly illuminate the irradiated surface. Item 8. An illumination optical device according to item 7. 9. An illumination optical apparatus for illuminating a surface to be illuminated, comprising: a light source means for supplying a light beam; and a light beam for converting the light beam from the light source means into a light beam having a predetermined cross section or a light beam having a predetermined light intensity distribution. A first light beam conversion element, and a first light beam conversion element for condensing the light beam from the first light beam conversion element.
A variable power optical system; a second light beam converting element for converting a light beam from the first variable power optical system into a light beam having a predetermined cross section or a light beam having a predetermined light intensity distribution; and a light beam from the second light beam converting element. Second for condensing light
A variable power optical system, an optical integrator for receiving a light beam from the second variable power optical system and uniformly illuminating the irradiated surface, and a light guide for guiding a light beam from the optical integrator to the irradiated surface. An optical optical system, wherein the second light beam conversion element is disposed at a predetermined distance from a light condensing position of the first variable power optical system or a front focal position of the second variable power optical system. An illumination optical device, comprising: 10. An apparatus according to claim 9, further comprising adjusting means for adjusting one of said first light beam converting element and said second light beam converting element according to a change in illumination conditions. 3. The illumination optical device according to claim 1. 11. One of the first light beam conversion element and the second light beam conversion element has a first diffractive optical element and a second diffractive optical element provided so as to be interchangeable with each other, and the adjusting means. The illumination optical system according to claim 10, wherein the first and second diffractive optical elements adjust the first or second diffractive optical element according to switching between the first and second diffractive optical elements. apparatus. 12. The illumination optical device according to claim 1, further comprising: a projection optical system for projecting and exposing a mask pattern set on the surface to be irradiated onto a photosensitive substrate. An exposure apparatus, comprising: 13. An exposure step of exposing the pattern of the mask on the photosensitive substrate by the exposure apparatus according to claim 12, and a developing step of developing the photosensitive substrate exposed in the exposure step. A method for manufacturing a micro device, comprising: 14. A method for manufacturing a micro device, comprising: an illumination step of illuminating a mask using an illumination system; and a transfer step of projecting and transferring a pattern image of the mask onto a photosensitive substrate using a projection system. The method of manufacturing a micro device, comprising: a changing step of changing an illumination condition for the mask; and adjusting a diffractive optical element in the illumination system according to the change of the illumination condition by the changing step.