JP2001068409A - Illumination optical device, scanning exposure device, and exposure method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To evenly illuminate an object surface arcuately or rectangularly with high efficiency by allowing an internal-reflection optical member which forms a plurality of source images based on the optical flux from a rectangular light supply means in cross section, for a rectangular region. SOLUTION: The optical flux emitted from an internal-reflection optical member 302 passes a relay optical system 40, and then is made incident on an internal-reflection optical member 500 with a rectangular cross section which forms a plurality of illumination source images. At an incident plane position A21 of the internal-reflection optical member 50, a plurality of linear or rectangular illumination source images are formed by the internal-reflection optical member 302. The optical flux from the illumination source image is repeatedly reflected inside the internal-reflection optical member 500 for ejection. By configuring the internal-reflection optical member 500 so as to form the illumination source image which matches the size of the region, a reticule R is evenly lit arcuately or rectangularly at a high lighting efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination optical device for illuminating an object to be irradiated in an arc shape or a rectangular shape, and more particularly to an illumination optical device suitable for an exposure apparatus for manufacturing a semiconductor.

[0002]

2. Description of the Related Art In the related art, for example, an illumination optical device as shown in FIG. 14 is applied to an exposure apparatus for manufacturing a semiconductor. As shown in FIG. 14A, a light beam from a light source 1 such as a mercury arc lamp is condensed by an elliptical mirror 2 and then converted by a collimator lens 3 into a parallel light beam. Then, as shown in FIG. 14B, the parallel light beam passes through a fly-eye lens 4 formed of an aggregate of lens elements 4a having a rectangular cross section, so that a plurality of light source images are formed on the exit side thereof. Is done. In this light source image position,
An aperture stop 5 having a circular opening is provided.
Light beams from the plurality of light source images are condensed by the condenser lens 6 and uniformly illuminate the reticle R as an object to be irradiated in a superimposed manner.

The circuit pattern on the reticle R is transferred onto the wafer W by the projection optical system 7 including the lenses 71 and 72 by the above illumination optical device. This wafer W
Are mounted on a wafer stage WS that moves two-dimensionally. In the exposure apparatus of FIG. 14, when the exposure of one shot area on the wafer is completed, the exposure apparatus sequentially performs exposure for the next shot area. A so-called step-and-repeat type exposure that two-dimensionally moves the wafer stage is performed.

[0004]

Incidentally, in recent years, a reticle R is irradiated with a rectangular or arc-shaped light beam, and the reticle R and the wafer W arranged conjugate with respect to the projection optical system are scanned in a certain direction. In order to transfer the circuit pattern of the reticle R onto a wafer under high throughput, a scanning exposure method has been proposed.

Here, in order to apply the illumination optical device as shown in FIG. 14 to the scanning exposure method, it is necessary to illuminate a reticle with, for example, a rectangular light beam. It is conceivable to configure the fly-eye lens 4 as shown in FIG. That is, the fly-eye lens 4
In order to illuminate the reticle R with the light beams from the individual lens elements constituting a rectangular shape superimposed on the reticle R, the cross section of the lens element 4a constituting the fly-eye lens 4 is irradiated as shown in FIG. The lens element 4a having this rectangular lens cross section is formed as an aperture stop in order to form a rectangular shape similar to the shape of the area and to make the numerical aperture of the illumination optical system equal to the illumination area on the reticle R. 5 are bundled in a square so that the circular openings are inscribed. Thereby, reticle R can be illuminated in a rectangular shape with high illumination efficiency.

However, when a high-output excimer laser or the like is used as a light source for illumination, the destruction of the lens element 4a constituting the fly-eye lens 4 is suppressed.
By increasing the number of lens elements 4a,
Although it is necessary to reduce the light intensity at the point a, in the fly-eye lens as shown in FIG.
There is a problem that the thickness of “a” in the short direction becomes thin, and the production becomes extremely difficult.

Accordingly, an object of the present invention is to uniformly illuminate a surface to be illuminated in an arc shape or a rectangular shape with high illumination efficiency.

[0008]

The present invention achieves the above object by, for example, as shown in FIGS.
An illumination optical device for illuminating an object to be irradiated (R) in a predetermined illumination area, comprising: a light supply unit (10, 2) for supplying a light beam.
0) and an internal reflection type integrator (500) for forming a plurality of light source images based on the light flux from the light supply means.
Wherein the internal reflection type integrator has a rectangular cross section, and the illumination area has a rectangular shape.

Further, according to the present invention, as shown in FIGS. 10, 11 and 13, the pattern on the reticle is scanned on the wafer while scanning the reticle (R) on which the circuit pattern is formed and the wafer (W). A scanning exposure apparatus for forming a predetermined illumination area on the reticle, and a projection optical system (80) for conjugate the reticle and the wafer. The illumination optical device includes: a light supply unit (10, 20) for supplying a light beam; an internal reflection type integrator (500) for forming a plurality of light source images based on the light beam from the light supply unit; A condenser optical system (6) that forms the illumination area on the reticle based on illumination light from an internal reflection type integrator.
0), and illuminates the reticle with illumination light obliquely in order to improve the resolution and depth of focus of the projection optical system.

The present invention also relates to a reticle (R) on which a circuit pattern is formed and a wafer (W) while scanning a pattern on the reticle on the wafer, as shown in FIGS. 10, 11 and 13, for example. A scanning exposure apparatus for forming a predetermined illumination area on the reticle, and a projection optical system (80) for conjugate the reticle and the wafer. The illumination optical device includes: a light supply unit (10, 20) for supplying a light beam; an internal reflection type integrator (500) for forming a plurality of light source images based on the light beam from the light supply unit; A condenser optical system (6) that forms the illumination area on the reticle based on illumination light from an internal reflection type integrator.
0), and a stop (S ₁₁ ) located in a position on the optical path between the internal reflection type integrator and the reticle, where the plurality of light source images are formed.

Further, the present invention relates to, for example, FIGS.
Reticle (R) on which a circuit pattern is formed as shown in FIG.
A scanning exposure apparatus for transferring a pattern on the reticle onto a wafer while scanning the wafer and a wafer (W), and an illumination optical apparatus for forming a predetermined illumination area on the reticle;
A projection optical system (80) for making the reticle and the wafer conjugate. The illumination optical device includes a light supply unit (10) that supplies a light beam, an internal reflection type integrator (500) that forms a plurality of light source images based on the light beam from the light supply unit, and the light supply device. Anamorphic optical member (20) disposed between the means and the illuminated object.

[0012]

FIG. 1 shows an example in which an illumination optical apparatus according to a first embodiment of the present invention is applied to an exposure apparatus for manufacturing a semiconductor. FIG. 1A is a diagram illustrating a configuration of the device of the first embodiment when viewed from directly above, and FIG. 1B is a diagram illustrating a cross-sectional configuration of the device of FIG. 1A when viewed from a lateral direction. It is. Hereinafter, the first embodiment will be described in detail with reference to FIG.

As shown in FIG. 1, the light supply means for supplying a parallel light beam having a rectangular light beam cross section is composed of a parallel light beam supply unit 10 and a light beam shaping unit 20, and an excimer laser or the like is used as the parallel light beam supply unit. 248 nm (KrF)
Alternatively, a parallel light beam having a wavelength of 192 nm (ArF) is output, and the cross-sectional shape of the parallel light beam at this time is rectangular. The parallel light beam from the light source 10 enters a beam shaping optical system 20 as a light beam shaping unit that shapes the light beam into a light beam having a predetermined cross-sectional shape. The beam shaping optical system 20 is composed of two cylindrical lenses (21, 22) having a refractive power in a direction perpendicular to the paper surface of FIG. 1A (the paper surface direction of FIG. 1B). The cylindrical lens 21 on the light source side has a positive refractive power and condenses the light flux in the direction of the paper surface of FIG. 1B, while the cylindrical lens 22 on the illuminated surface has a negative refractive power. The divergent light beam from the cylindrical lens 21 on the light source side is diverged and converted into a parallel light beam. Therefore,
The parallel light flux from the light source 1 via the beam shaping optical system 20 is shaped such that the light flux width in the paper surface direction in FIG. The beam shaping optical system 20 may be a combination of a cylindrical lens having a positive refractive power, and may be an anamorphic prism or the like.

The shaped light beam from the beam shaping optical system 20 is incident on an optical integrator 30 as first multiple light source image forming means for forming a plurality of light source images arranged linearly. As shown in FIG. 1, the optical integrator 30 has a configuration in which a plurality of biconvex lens elements 30a each having a substantially square lens cross section are arranged in a row in the direction of the paper surface of FIG. The optical integrator 30 has a rectangular cross section as a whole. Each biconvex lens element 30a has the same curvature (refractive power) in the direction of the paper surface of FIG. 1A and the direction of the paper surface of FIG. 1B.

For this reason, the optical integrator 3
The parallel luminous fluxes passing through the individual lens elements 30a constituting 0 are condensed, and a light source image is formed on the exit side of each lens element 30a. Therefore, the lens element 30 is located at the exit side position A ₁ of the optical integrator 30.
A plurality of light source images corresponding to the number a are formed so as to be arranged in a straight line (one line), and here a secondary light source is substantially formed.

The light beam from the linear secondary light source formed by the optical integrator 30 is condensed by the relay optical system 40 to form a second multi-light source image forming a plurality of light source images arranged in a rectangular shape. The light enters the optical integrator 50 as a means. As shown in FIG. 1, the optical integrator 50 includes a plurality of biconvex lens elements 50 having a rectangular lens cross section.
a are arranged in a line in the direction of the paper surface of FIG. 1B, and the lens element 50a is
The cross-sectional shape (aspect ratio) of the optical integrator 3
It is configured to be similar to the cross-sectional shape (aspect ratio) of 0. The optical integrator 50 as a whole has a square cross section. Each lens element 50a has the same curvature (refractive power) in the direction of the paper of FIG. 1A and the direction of the paper of FIG. 1B.

For this reason, the optical integrator 5
The light fluxes from the optical integrators 30 passing through the individual lens elements 50a constituting 0 are condensed, and a light source image is formed on the exit side of each lens element 30a. Thus, on the exit side position A ₂ of the optical integrator 30, a plurality of light source images arranged in a square shape is formed, wherein substantially tertiary light sources are formed on.

Here, the optical integrator 50
The number of the plurality of light source images arranged in a square is defined by the number of lens elements 30a constituting the optical integrator 30 and the number of lens elements 50a constituting the optical integrator 50 being M At this time, N × M pieces are formed. That is, a plurality of light source images formed by the optical integrator 30 are converted by the relay optical system 40 into the optical integrator 5.
Because it is formed on the light source image position of each lens element 50a constituting the 0, on the exit side position A ₂ of the optical integrator 50, a total of N × M pieces of light source images are formed.

The relay optical system 40 is an optical
Incident surface position B of integrator 30 ₁ And optical
Incident surface position B of the integrator 50_Two And conjugate
In addition, the emission surface position A of the optical integrator 30₁ 
And the exit surface position A of the optical integrator 50_Two When
Is conjugated. Position A where this tertiary light source is formed _Two 
Inscribes the cross section of the optical integrator 50
Aperture stop S having a circular opening₁ Is provided
This aperture stop S₁ -Order light formed into a circular shape by
The luminous flux from the source is collected by the condenser optical system 60.
The reticle R as an object to be illuminated
I will tell.

Here, the condenser optical system 60 collects light from a tertiary light source image relayed by the relay optical system (61, 62) and the relay optical system (61, 62). It has a special reflecting mirror 63 that illuminates and directly forms an arc-shaped illumination area on the reticle R. First, the relay optical system (61, 62) includes a first relay lens 61 provided as the front focal point coincides with the exit surface position A ₂ of the optical integrator 50,
And a second relay lens 62 that forms the rear side focal position A ₃ a light source image by condensing the light flux from the first relay lens 61. Then, in the back focal point B ₃ after the first relay lens 61, field diaphragm S _2, which has a rectangular or substantially rectangular opening is provided in order to accurately define the illumination area to illuminate the reticle R ing.

On the other hand, the special reflecting mirror 63 is, as shown in FIG.
And a reflecting surface 63a having a predetermined curvature in an arc shape as a whole.
Specifically, from the vertex O of the parabola PA,
A predetermined distance along the axis of symmetry Ax0 of the parabola PA
Position Y₀ Is the axis of symmetry Ax ₀ Group that passes perpendicular to
Quasi-axis Ax₁ Parabolic torical shape rotated around
It is composed of one part of the rolling body.

[0022] Here, as shown in FIG. 1 (b), the vertex O of the parabola PA forming the reflecting surface 63a is the origin, Y-axis the symmetry axis Ax ₀ which coincides with the surface to be illuminated (reticle R), symmetrical The axis perpendicular to the axis Ax ₀ and perpendicular to the surface to be illuminated (reticle R) is the X axis, and the parabola PA forming the reflecting surface 63a is y = α.
x ² (where, alpha is a constant) When the reference axis Ax ₁ passes the position Y ₀ on the symmetry axis Ax ₀ was separated by 3 / (4.alpha.) from the origin from O, its position Y ₀ 1 / (2.alpha ) at a position on the reference axis Ax ₁ that are separated, center of the light source image of the optical integrator 50 which is re-imaged is formed by the relay optical system (61, 62).

Therefore, the light beam from the center position of the light source image of the optical integrator 50 re-imaged by the relay optical system (61, 62) is a parallel light beam having an arc-shaped light beam cross section due to the condensing action of the special reflecting mirror 63. is converted into an arcuate illumination region around the position on the symmetry axis Ax ₀ was separated by 1 / (4α) from the origin O is formed on the reticle R.

Here, if the shape of the reflecting surface 63a of the special reflecting mirror 63 is quantitatively shown, the special reflecting mirror 63 has a parabolic toric rotating body satisfying the following equations (1) and (2). It is preferable to be constituted by one part of the following.

[0025]

(Equation 1)

[0026]

(Equation 2)

However, x, y, and z are defined with the vertex O of the parabola PA (y = αx ² ) forming the reflection surface 63a as the origin.
The direction perpendicular to the symmetry axis Ax0 and perpendicular to the surface to be illuminated is the X axis,
Y-axis direction which coincides with the symmetry axis Ax _0, the reference axis Ax ₁ and a direction perpendicular to the vertical and symmetry axis Ax ₀ the coordinates when the Z-axis, and R is the reference axis Ax ₁ and symmetry axis Ax parabola to form a reflecting surface 63a from the intersection Y ₀ of ₀ PA (y = _α
x ² ) Indicates the distance to the vertex O.

When the above expressions (1) and (2) are satisfied, the light beam diverging from the light source image formed at the position A ₃ is converted by the special reflecting mirror 3 into a parallel light beam having an arc-shaped light beam cross section. Thus, an arc-shaped illumination area in which the telecentricity and the Koehler illumination state are maintained is formed. The center of the light source image formed at the position A ₃ is represented by coordinates ((2α) ⁻¹ , 3
(4α) ⁻¹ , 0), and the center C _{BF of the} irradiated area shown in FIG. 1B is a part of a circle in the YZ plane that satisfies the following expression (3).

[0029]

(Equation 3)

With the above-described configuration of the condenser optical system,
An arc-shaped illumination area can be directly formed on the reticle R under a high illumination efficiency without causing a light quantity loss. Next, transfer of the circuit pattern on the reticle R onto the wafer W using the illumination optical device shown in FIG. 1 will be described with reference to FIG.

FIG. 2 shows a configuration of a projection exposure section for transferring a circuit pattern on a reticle R onto a wafer W using the illumination optical device shown in FIG. As shown in FIG. 2, the reticle R held on the reticle stage RS and the wafer W mounted on the wafer stage WS are arranged conjugate with respect to the projection optical system 80, and the arc is formed by the condensing action of the special reflecting mirror 63. The illuminated circuit pattern portion of the reticle R is projected onto the wafer W by the projection optical system 80.

The projection optical system 80 has a concave mirror 81 and a convex mirror 82 as a basic configuration, and is provided so that the centers of curvature of the concave mirror 81 and the convex mirror 82 are almost coincident. Further, between the reticle R and the concave mirror 81 and between the convex mirror 82 and the wafer W, there are provided reflecting mirrors M ₁ and M ₂ for bending the optical path, respectively. At this time, the entrance pupil of the projection optical system 80 is located near the convex mirror 82, and the entrance pupil is conjugate with the light source image formed by the second relay lens 62 of the relay optical system. Therefore, since a light source image formed by the illumination optical system provided above the reticle is formed on the entrance pupil of the projection optical system, so-called Koehler illumination is performed.

In actual exposure with the above configuration,
The reticle stage RS and the wafer stage WS move in the direction of the arrow, and the circuit pattern on the reticle is
Since the circuit pattern on the reticle is uniformly illuminated in an arc shape with high illumination efficiency, scanning exposure can be realized at a much higher throughput than in the past.

In the first embodiment shown in FIG. 1, an excimer laser or the like for supplying a parallel light beam is used as the parallel light beam supply unit. However, the present invention is not limited to this. For example, g-line (436 nm) or i-line (365 nm) ) Etc., a collimated light beam using a mercury arc lamp that emits light of a wavelength such as a collimator lens system that converts the light beam condensed by the elliptical mirror into a parallel light beam You may comprise a supply part. Further, in the present embodiment, the projection optical system 80 is constituted by a reflection system, but it goes without saying that the projection optical system 80 may be constituted by a refraction system.

Next, a second embodiment of the present invention will be described with reference to FIG. The second embodiment shows an example in which an illumination optical device that illuminates a reticle R as a surface to be irradiated in a rectangular shape (slit shape) is applied to an exposure device for manufacturing a semiconductor. The difference from the first embodiment shown in FIG. 3 is that, as shown in FIG.
Are used to illuminate the reticle R in a rectangular shape, and the circuit pattern on the reticle R is transferred onto the wafer W using the refraction-based projection optical system 80.

As shown in FIG. 3, a parallel light beam output from the excimer laser 10 passes through a beam shaping optical system 20 and is converted into a light beam having a predetermined beam cross section. lens element 30a is focused by the optical integrator 30 constructed are arranged in a row shape in direction perpendicular to the paper, arranged in a row shape to the direction perpendicular to the paper of the exit side position a ₁ A plurality of light source images are formed. After passing through the relay optical system 40, the luminous fluxes from the plurality of light source images are condensed by the optical integrator 50 configured by arranging a plurality of lens elements 50a having a rectangular lens cross section in a square shape. Receiving the injection side position A of this
_{In 2} , a plurality of light source images arranged in a square shape are formed. This is the light source image position A ₂ and S ₁ aperture stop having a circular opening is provided, the light beams from the plurality of light source images a circular shape by this aperture stop S ₁ is the surface to be illuminated (reticle R) is incident on a refraction condenser optical system 60 for illuminating R) in a rectangular shape. The condenser optical system 60 is arranged such that its front focal position coincides with the position A ₂ of the exit side surface of the optical integrator 50 and its rear focal position coincides with the illuminated surface of the reticle R. Accordingly, the light beams from the plurality of light source images formed by the optical integrator 50 receive the condensing action of the condenser optical system 60 and illuminate the reticle R uniformly in a superimposed rectangular shape.

As described above, the circuit pattern on the reticle R illuminated in a rectangular shape is projected onto the wafer W by the projection optical system 80.
When the reticle stage RS holding the reticle R and the wafer stage WS holding the wafer W move in the direction of the arrow, the circuit pattern formed on the entire surface of the reticle R is transferred onto the wafer W. You. At this time, although a plurality of light source images formed by the optical integrator 50 are formed on the pupil (entrance pupil) position of the projection optical system 80 (not shown), the pattern on the reticle R under Koehler illumination is Is transferred onto the wafer W.

In the second embodiment, as in the first embodiment shown in FIG. 1, an excimer laser or the like for supplying a parallel light beam is used as a parallel light beam supply section. For example, as shown in FIG. 12, a mercury arc lamp 11 arranged at a first focal position of the elliptical mirror 12 and outputting a wavelength light such as a g-line (436 nm) or an i-line (365 nm);
Light from the elliptical mirror 12 is collected by the
The collimated light beam supply unit may be configured using a collimator lens system 13 that converts a light beam having a light source image formed at a focal position into a parallel light beam.

Now, the optimum configuration of the two optical integrators (30, 50) of each embodiment shown in FIGS. 1 to 4 will be described. 1 and 2 shown in FIGS.
In the embodiment, as shown in FIG. 5A, an arc-shaped illumination area is formed on the reticle R, and in the second embodiment shown in FIG. 3 and the modification of the second embodiment shown in FIG. As shown in FIG. 5B, a rectangular (slit-shaped) illumination area is formed on the reticle R, but the two optical integrators (30, 50) are formed in a circle formed on the reticle R. It is desirable to form a light source image having a size commensurate with the size of the arc-shaped or rectangular illumination region.

As shown in FIGS. 5 and 6, the width of the central portion of the arc-shaped illumination area or the length of the rectangular illumination area in the short direction is s, the length of the arc (chord) or the rectangular shape. T is the length of the illumination area in the longitudinal direction, and the optical integrator 3
0, the length in the longitudinal direction of the entire cross section is m ₁ , and the length of the entire optical integrator 30 in the longitudinal direction is n.
_{When set to 1} , the optical integrator 30

[0041]

S / t = n ₁ / m ₁ ··· (4) It is desirable that the relationship be substantially satisfied.
At this time, for example, assuming that the ratio of the vertical and horizontal lengths of the cross section of each lens element 30a constituting the optical integrator 30 is 1: 1, this lens element 30a has m ₁ /
Only n ₁ pieces are arranged in one column.

Further, since a plurality of light source images are formed by the optical integrator 30 on the exit side of each of the lens elements 50a constituting the optical integrator 50, as shown in FIG. 7, the lens elements constituting the optical integrator 50 are formed. When the length in the longitudinal direction at the cross section of 50a is m ₂ and the length at the cross section of the lens element 50a is m ₂ , the lens element 50a

[0043]

It is preferable that the following expression is satisfied: n ₁ / m ₁ = n ₂ / m ₂ (= s / t) (5) At this time, for example, assuming that the entire cross section of the optical integrator 50 is configured as an accurate square, the lens element 50a
Only m ₂ / n ₂ are arranged in one row.

Here, as an example, the width s of the central part of the arc with respect to the length t of the arc (chord) in the arc-shaped illumination area
Or the length t in the short direction in the rectangular illumination area
Ratio of the length s in the longitudinal direction in this area to 1/1
1, and the ratio of the vertical and horizontal lengths of the cross section of the lens element 30a is 1.
Assuming that the entire cross section of the optical integrator 50 is configured to be an accurate square, the optical integrator 30 has eleven lens elements 30a arranged in a line as shown in FIG. And
In the optical integrator 50, as shown in FIG. 7, eleven lens elements 50a are arranged in one line. Therefore, on the emission side of the optical integrator 30, eleven light source images arranged linearly (one row) are formed, and on the emission side of the optical integrator 50, 121 light source images arranged in a square shape (11 × 11
Light source images are formed. Thereby, it is possible to uniformly illuminate the reticle R in an arc shape or a rectangular shape with high illumination efficiency.

In each of the embodiments shown in FIGS.
The example in which the lens elements constituting the two optical integrators (30, 50) are arranged in one line has been described. Next, as a modified example of each embodiment, two or more lens elements 30a of the optical integrator 30 are constituted. An example and an example in which the lens elements of the optical integrator 50 are configured in two or more rows will be described.

First, in each of the embodiments shown in FIGS.
Although an optical integrator 30 in which a plurality of lens elements are arranged in a line as shown in FIG. 6 is used, an example in which an optical integrator 30 as shown in FIG. 8 is provided instead will be described. FIG. 8 shows an optical integrator 30 in which a plurality of lens elements 30a having the same curvature (refractive power) in the X direction and the Z direction perpendicular thereto are arranged in two rows. The lens element 30a has a square lens cross section, and the optical integrator 30 as a whole is described in (4) above.
It is assumed that the lens has a lens section satisfying the expression.

Now, the number of rows of lens elements 30a constituting the optical integrator 30 as shown in FIG.
Then, the optical integrator 30 in which the plurality of lens elements 30a are arranged in N ₁ rows provides N ₁ ² m ₁ / n ₁
Will be composed of pieces of lens elements 30a, the this the exit side, a plurality of light source images arranged in N ₁ ² m ₁ / n ₁ or rectangular is formed.

Accordingly, the lens element 50a constituting the optical integrator 50 as shown in FIG. 7 satisfies the above expression (5), and the number m ₂ / n _{2 of} the lens elements 50a is arranged in a line to form the optical integrator 50.
If the entire cross-section is formed at the correct square, on the exit side of the optical integrator 50, N arranged in a square shape ^{_{1 2 m 1 m 2 / (}} n 1 n 2) pieces of the light source image is formed of is, than in the first embodiment, it is possible to form many light source images N ₁ ² times, it is possible to obtain a more uniform illumination intensity on the reticle R as the irradiated surface.

Here, as an example, the ratio of the width s of the center portion to the length t of the arc (chord) in the arc-shaped illumination area, or the ratio of this to the length t in the short direction of the rectangular illumination area. The ratio of the length s in the longitudinal direction in the region is set to 1/11, the ratio of the length and width of the cross section of the lens element 30a is 1 to 1, and the entire cross section of the optical integrator 50 is formed of an accurate square. As shown in FIG. 8, in the optical integrator 30, forty-four lens elements 30a are arranged in two rows, and in the optical integrator 50, as shown in FIG.
0a will be arranged in a line. Therefore, 44 light source images arranged in two rows are formed on the emission side of the optical integrator 30, and 48 light sources arranged in a square shape are formed on the emission side of the optical integrator 50.
Four (44 × 11) light source images are formed.

Next, in each of the embodiments shown in FIGS.
As shown in FIG. 7, the optical integrator 50 in which a plurality of lens elements 50a are arranged in one row is shown.
An example in which an optical integrator 50 as shown in FIG. 9 is provided instead of this will be described. FIG. 9 shows an optical integrator 50 in which a plurality of lens elements 50a having the same curvature (refractive power) in the X direction and the Z direction perpendicular thereto are arranged in two rows.
Here, it is assumed that the individual lens elements 50a are configured to satisfy the above equation (5) so that the entire optical integrator 50 has a square shape.

[0051] Now, the number of columns of lens element 50a constituting the optical integrator 50 as shown in FIG. 9 N ₂
Then, the optical integrator 50 in which the lens elements 50a are arranged in N ₂ rows is constituted by N ₂ ² m ₂ / n ₂ lens elements 50a. For this reason, as described above, the optical integrator 3 having a configuration in which m ₁ / n ₁ lens elements 30a are arranged in one line.
0, m ₁ / n ₁ light source images are linearly arranged, and N ₂ ² m ₂ / n ₂ lens elements 50a are formed.
Is composed of N ₁ columns.
On the exit side ^{_{is, N 2 2 m 1 m 2}} / (n 1 n 2) pieces plurality of light source images arranged in a square shape is formed. Therefore, than in the first embodiment, it is possible to form many light source images N ₂ ² times, it is possible to obtain a more uniform illumination intensity on the reticle R as the irradiated surface.

Here, as an example, the ratio of the width s of the central portion to the length t of the arc (chord) in the arc-shaped illumination region, or the ratio of the width t in the short-side direction t in the rectangular illumination region. The ratio of the length s in the longitudinal direction in the region is set to 1/11, the ratio of the length and width of the cross section of the lens element 30a is 1 to 1, and the entire cross section of the optical integrator 50 is formed of an accurate square. In the optical integrator 30, eleven lens elements 30a are arranged in one row as shown in FIG. 6, and in the optical integrator 50, as shown in FIG.
0a are arranged in two rows. Accordingly, eleven light source images arranged in one line are formed on the emission side of the optical integrator 30, and 48 light sources arranged in a square shape are formed on the emission side of the optical integrator 50.
Four (11 × 44) light source images are formed.

As described above, one of the optical integrators (30, 50) is provided with a plurality of reticle elements.
Although it is possible to configure the optical integrators arranged in rows and the other as an optical integrator in which a plurality of lens elements are arranged in two or more rows,
Further, as shown in FIGS. 8 and 9, two optical integrators (30, 50) in which a plurality of lens elements are arranged in two or more rows may be combined.

In this case, the plurality of lens elements 30a are N ₁
The optical integrator 30 composed of columns is N
_The optical integrator 50, which includes ¹² m ₁ / n ₁ lens elements 30a and the plurality of lens elements 50a are arranged in N ₂ rows, has N ₂ ² m ₂ / n ₂ lens elements. 50a. Thus, on the exit side of the optical integrator 30, N ₁ ² m ₁
/ N ₁ A plurality of light source images arranged in a rectangular shape are formed, and the emission side of the optical integrator 50 is
^{_{1 2 N 2 2 m 1 m}} 2 / (n 1 n 2) pieces plurality of light source images arranged in a square shape is formed.

Accordingly, two optical integrators (30, 5) in which a plurality of lens elements are arranged in two or more rows.
By combining 0), a synergistic illuminance uniformity effect by two optical integrators can be obtained, which is extremely effective. In each of the embodiments described above, the optical integrator 30 functions as the second multiple light source image forming unit to form a plurality of light source images arranged in a square shape. Since the aperture is limited to a circular light beam by the provided aperture stop S _1, the cross-sectional shape of the optical integrator 30 is slightly distorted from a square shape to a shape close to a circle corresponding to the shape of the circular opening of the aperture stop S _1. Needless to say, it can be configured.

Next, a third embodiment of the present invention will be described with reference to FIGS. 10A is a diagram illustrating a configuration of the device of the third embodiment when viewed from directly above, and FIG. 10B is a diagram illustrating a cross-sectional configuration of the device of FIG. 10A when viewed from a lateral direction. It is. In the third embodiment, instead of the two optical integrators (30, 50) of the first embodiment shown in FIGS. 1 and 2, as shown in FIG. 12, an internal reflection type optical member such as a glass rod (a prism-shaped optical member) is used. This shows an example of uniformly illuminating the reticle R in an arc shape using an internal reflection type integrator).

As shown in FIG. 10, the excimer laser 10
The first multi-source image forming means 300 for forming a plurality of light source images linearly arranged after the parallel light flux output from Incident on. This first multiple light source image forming means 30
Reference numeral 0 denotes a condensing lens 301 for condensing a parallel light beam from the beam shaping optical system 20, and an internal reflection type optical member 302 having a substantially square cross section, and which has passed through the condensing lens 301. The light flux is an internal reflection type optical member 302.
After being light source image on the incident plane position A ₁₁ of forming the light beam from the light source image is repeatedly internally reflected by the optical member internal reflection type, emitted from the exit end of the member 302. At this time, the incident plane position A ₁₁ of the internal reflection type optical member 302, a linear or rectangular shape of a plurality of light source images (virtual image) is formed,
The member 3 as if there were a plurality of light source images on the incident surface position A ₁₁
A light beam is emitted from the emission end of the light emitting element 02.

The light beam emitted from the internal reflection type optical member 302 passes through the relay optical system 40, and then forms a rectangular multiple light source image forming means for forming a plurality of light source images arranged in a square shape. Internal reflection type optical member 5 having a cross section
00, and the incident surface position A ₂₁ of this member is
A plurality of linear or rectangular light source images (real images) are formed. Then, the plurality of light source images (real images)
Are repeatedly reflected inside the optical member 500 of the internal reflection type, and are emitted from the exit end of the member 500.
At this time, the incident surface position A of the internal reflection type optical member 500
_{At 21} , a plurality of square light source images (virtual images) are formed from the plurality of light beams by the member 302, and the light beams are emitted from the exit end of the member 500 as if there were a plurality of light source images on the incident surface position A 21. .

The relay optical system 40 conjugates the incident surface position A ₁₁ of the internal reflection type optical member 302 with the incident surface position A _{21 of the} internal reflection type optical member 500, and also controls the internal reflection type optical member 500. an exit surface position B ₂₁ of the exit plane position B ₁₁ and internal reflection type optical member 500 of the member 302 are conjugate. By the way, the light flux emitted from the inner reflection type optical member 500 is condensed by the condenser optical system 60,
The irradiated surface (reticle R) is illuminated in an arc shape in a superimposed manner.

Here, the condenser optical system 60 is composed of a first condenser lens 64 of a refraction system and a second condenser lens 63 of a reflection system. aperture stop S ₁₁ is provided with an elliptical opening. For this reason,
Light rays emitted from the optical member 500 of the inner surface reflection type, is condensed by the first condenser lens 64, an aperture stop S ₁₁
The position A _31, the real image of the plurality of light source images formed by the optical member 500 of the inner surface reflection type is formed. Then, the light beams from the plurality of light source images formed in a circular shape by this aperture stop S ₁₁ is the condensing action of the second condenser lens 63, an arcuate illumination region is formed on the irradiated surface (reticle R) Form directly.

As described above, the circuit pattern on the reticle R illuminated in an arc shape is transferred onto the wafer W by the projection optical system 80 as shown in FIG. 11, and the reticle stage RS holding the reticle R and the wafer W Is moved in the direction of the arrow, and the circuit pattern formed on the entire surface of the reticle R is transferred onto the wafer W.

At this time, since a plurality of light source images formed by the internal reflection type optical member 500 are formed on the pupil (entrance pupil) position of the projection optical system 80 (not shown), the Koehler illumination is not required. With this, the pattern on the reticle R is transferred onto the wafer W. In this embodiment, a refraction lens is used instead of the second condenser lens 64 of the reflection system, and the front focal position of the refraction lens is adjusted to a plurality of light source image positions A formed by the first condenser lens 64. _By arranging the refracting lens at the same position as the reticle R and the rear focal position of the lens of the refracting system, it is possible to illuminate the reticle R in a rectangular shape (slit shape).

In the third embodiment, an excimer laser or the like that supplies a parallel light beam is used as the parallel light beam supply unit. However, the present invention is not limited to this. For example, a wavelength such as a g-line (436 nm) or an i-line (365 nm) is used. Constructs a parallel beam supply unit using a mercury arc lamp that outputs light, an elliptical mirror that condenses light from the mercury arc lamp, and a collimator lens system that converts the light beam condensed by the elliptical mirror into a parallel light beam You may.

Further, it is needless to say that the internal reflection type optical member 500 is not limited to the glass rod, but may be a hollow prismatic internal reflection type optical member. As described above, in the third embodiment, two internal reflection optical members (302, 500) having an extremely simple structure can be formed, and formed on the entrance surface of each internal reflection optical member (302, 500). The optical path length of the light beam from each light source image in the plurality of light source images (virtual images) is determined by the internal reflection type optical member (302, 50
Since it differs according to the number of times of internal reflection within 0), it has an effect of reducing the coherency of the light flux, and is particularly effective when a light source such as a laser is used.

Next, the optimum configuration of the two internal reflection type optical members (302, 500) in the third embodiment will be described with reference to FIGS. Here, FIG. 12A is a perspective view of the internal reflection type optical member 302,
(B) is a perspective view of the internal reflection type optical member 500. In the third embodiment shown in FIGS. 10 and 11, (a) of FIG.
As shown in FIG. 5, an arc-shaped illumination area is formed on the reticle R, and the configuration of the condenser optical system 60 of the third embodiment is slightly changed as described above. Although a rectangular (slit-shaped) illumination area can be formed on the reticle R, the two internal reflection type optical members (302, 500) can be used to form an arc-shaped or rectangular illumination area formed on the reticle R. It is desirable to form a light source image of a size commensurate with the size.

Now, as shown in FIGS. 5 and 12, the width of the center of the arc-shaped illumination area or the length of the rectangular illumination area in the short direction is s, the length of the arc (chord) or the rectangle. The length of the illumination area in the longitudinal direction is t, the length of the cross section of the internal reflection type optical member 500 in the short direction is u ₂ , and the internal reflection type optical member 50 is
When the length in the longitudinal direction of the cross section of 0 is v ₂ ,

[0067]

S / t = u ₂ / v ₂ (6) It is desirable to satisfy the following relationship. Further, when the length of one side of the cross section of the internal reflection type optical member 303 is u ₁ and the imaging magnification of the relay optical system is β,

[0068]

It is more desirable that the following relationship is satisfied: u ₁ = βu ₂ (7) Thus, 2
If the two internal reflection type optical members (302, 500) are configured so as to form a light source image having a size corresponding to the size of the illumination area, the reticle R is provided under a significantly higher illumination efficiency.
The top can be uniformly illuminated in an arc shape or a rectangular shape.

In the present invention, one of the optical integrator composed of a plurality of lens elements and the internal reflection type optical member is used as first multi-light source image forming means, and the other is used as second multi-light source image forming means. Needless to say, it may be configured as a means. Further, as described in each of the above-described embodiments, the beam shaping optical system 20 that shapes the light beam from the parallel light beam supply unit 10 into a light beam having a rectangular cross-sectional shape has a size of an arc-shaped or rectangular illumination area. It is desirable that the beams be shaped to match each other, whereby the light amount can be effectively used. At this time, the width of the center of the arc-shaped illumination area or the width of the rectangular illumination area in the short direction is s, and the length of the arc (chord) or the length of the rectangular illumination area in the longitudinal direction is t. When the length in the short direction of the cross section of the light beam emitted from the beam shaping optical system 20 is B _S , and the length in the long direction of the cross section of the light beam emitted from the beam shaping optical system 20 is B ₁ , s / t
= B _S / B _l is more preferably satisfied.

Further, in each of the above-described embodiments, the light supply means is constituted by the parallel light beam supply unit 10 for supplying the parallel light beam and the beam shaping optical system 20 for shaping the parallel light beam into a light beam having a rectangular cross section. However, the beam shaping optical system 20 constituting a part of the light supply means is not essential in the principle of the present invention. That is, if a light source or the like that supplies a parallel light beam having a rectangular cross-sectional shape is used as a light supply unit, an arc-shaped or rectangular illumination area can be formed on the illuminated surface (reticle R) without providing the beam shaping optical system 20. Thus, uniform illumination (Koehler illumination) of the illuminated surface (reticle R) can be realized with high illumination efficiency.

For example, a light source such as an excimer laser usually supplies a substantially parallel light beam having a rectangular cross section, so that the width of the center of the arcuate illumination area or the width of the rectangular illumination area in the short direction is provided. The length is s, the length of the arc (chord) or the length of the rectangular illumination area in the longitudinal direction is t, the length of the cross section of the excimer laser beam in the short direction is L _S , the length of the cross section of the excimer laser beam. When the length in the direction is _Ll , s
When the relationship of / t = L _S / L ₁ is almost satisfied,
Even if the light supply means is constituted only by a light source such as an excimer laser, the surface to be illuminated (reticle R) can be uniformly illuminated in an arc shape or a rectangular shape with extremely high illumination efficiency. The light supply means may be a light source for simply supplying a parallel light beam. Even in this case, the illumination target surface (reticle R) is uniformly illuminated in an arc shape or a rectangular shape (Koehler) under relatively high illumination efficiency. Lighting).

In each of the embodiments shown in FIGS. 1, 3, 4 and 10, the aperture stop (S ₁ , S ₁₁ ) having a circular aperture as shown in FIG. Are arranged, but instead of the aperture stop (S ₁ , S ₁₁ ), an aperture stop (S) as shown in FIGS. 13B and 13C is used.
_1, S ₁₁₎ may be disposed. However, FIG.
Ax in (c) indicates the optical axis position of the illumination optical system when the field stop of (c) in FIG. 13 is set in the illumination optical system.

As shown in FIG. 13B, if an aperture stop (S ₁ , S ₁₁ ) having a ring-shaped aperture is arranged, the illumination light is directed obliquely to the irradiation surface R (reticle). While illuminating from above, an arc-shaped or rectangular-shaped illumination area can be formed on the reticle R, so that the resolution and the depth of focus of the projection optical system 80 can be improved. Also,
Instead of an aperture stop (S ₁ , S ₁₁ ) having a circular opening as shown in FIG. 13A, as shown in FIG. 13C, with respect to the optical axis ax of the illumination optical system. By disposing an aperture stop (S ₁ , S ₁₁ ) having a plurality of eccentric (eg, two or four eccentric) apertures, the resolution and depth of focus of the projection optical system 80 are further improved. It becomes possible. The detailed technology for this is disclosed, for example, in Japanese Patent Application Laid-Open No. 4-225514.

[0074]

As described above, according to the present invention, it is possible to uniformly illuminate the surface to be illuminated in an arc shape or a rectangular shape (Koehler illumination) with high illumination efficiency without inducing a light quantity loss. It can sufficiently cope with a case where a high-output light source such as an excimer laser is used. Further, if the present invention is applied to a scanning type semiconductor manufacturing exposure apparatus, not only the illuminance distribution on the irradiated surface but also the illuminance distribution on the pupil plane of the projection optical system on which the light source image is formed can be uniform. Therefore, a sufficient resolution and depth of focus of the projection optical system can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration when an illumination optical device according to a first embodiment of the present invention is applied to an exposure apparatus for manufacturing a semiconductor.

FIG. 2 is a diagram showing a configuration of an exposure unit of the apparatus shown in FIG.

FIG. 3 is a diagram showing a configuration when an illumination optical device according to a second embodiment of the present invention is applied to an exposure apparatus for manufacturing a semiconductor.

FIG. 4 is a diagram showing a configuration of a modification of the device shown in FIG.

FIG. 5 is a diagram showing a state of an illumination area formed on a surface to be illuminated.

FIG. 6 is a diagram illustrating a cross-sectional view of an optical integrator 30 configured by arranging a plurality of lens elements in a line.

FIG. 7 is a diagram illustrating a cross-sectional view of an optical integrator 50 configured by arranging a plurality of lens elements in a line.

FIG. 8 is a diagram showing a cross section of an optical integrator 30 configured by arranging a plurality of lens elements in two rows.

FIG. 9 is a diagram showing a cross section of an optical integrator 50 configured by arranging a plurality of lens elements in two rows.

FIG. 10 is a diagram showing a configuration when an illumination optical device according to a third embodiment of the present invention is applied to an exposure apparatus for manufacturing a semiconductor.

FIG. 11 is a diagram showing a configuration of an exposure unit of the apparatus shown in FIG.

FIG. 12 is a perspective view illustrating a state of an internal reflection type optical member.

FIG. 13 (a) is an aperture stop when the aperture is circular.
(S₁ , S₁₁(B) is an open plan view showing the state of ()).
Aperture stop (S₁ , S₁₁)
(C) is an aperture stop (S).₁ , S₁₁)
A plurality of eccentricity with respect to the optical axis ax of the illumination optical system
Aperture stop when aperture is formed (S₁ , S ₁₁)
FIG.

FIG. 14 is a diagram showing a configuration when a conventional illumination optical device is applied to an exposure apparatus for manufacturing a semiconductor.

[Explanation of symbols]

 10 Excimer laser 20 Beam shaping optical system 30, 50 Optical integrator 40 Relay optical system Condenser optical system 300, 500 .... Internal reflection type optical members

Claims (24)

[Claims] 1. An illumination optical device for illuminating an object to be illuminated in a predetermined illumination area, comprising: a light supply means for supplying a light beam; An illumination optical device, comprising: a shape integrator; the internal reflection type integrator has a rectangular cross section; and the illumination region has a rectangular shape. 2. The length of the rectangular illumination area in the lateral direction.
S, the length in the longitudinal direction of the rectangular illumination area is t,
Length of the cross-section of the internal reflection type integrator in the short direction
U _Two, The longitudinal direction of the cross section of the internal reflection type integrator
The length of the direction_Two S / t = u_Two / V_Two 2. The illumination optical device according to claim 1, wherein
Place. 3. The illumination optical device according to claim 1, further comprising a stop arranged in an optical path between an exit end of the internal reflection type integrator and the object to be illuminated. 4. The stop according to claim 1, wherein the stop comprises a stop having a circular opening, a stop having a ring-shaped opening, or a stop having a plurality of openings eccentric to an optical axis. The illumination optical device according to claim 3. 5. The illumination optical device according to claim 4, wherein the plurality of apertures are exchangeable. 6. A condenser optical system disposed between the internal reflection type integrator and the object to be irradiated, wherein the stop is located at a position where a plurality of light source images are formed by the internal reflection type integrator. The illumination optical device according to claim 3, wherein the illumination optical device is arranged. 7. The apparatus according to claim 1, further comprising a condenser optical system for forming said illumination area on said object to be illuminated based on a light beam from said internal reflection type integrator. An illumination optical device according to claim 1. 8. The illumination optical device according to claim 1, wherein the internal reflection type integrator includes a glass rod or a hollow prismatic internal reflection type optical member. 9. A scanning exposure apparatus for transferring a pattern on the reticle onto a wafer while scanning a reticle on which a circuit pattern is formed and a wafer, wherein the predetermined illumination area is formed on the reticle. A scanning exposure apparatus comprising: the illumination optical device according to any one of Items 1 to 8; and a projection optical system that conjugates the reticle and the wafer. 10. The scanning exposure apparatus according to claim 9, wherein a plurality of light source images formed by said internal reflection type integrator are formed at pupil positions of said projection optical system. 11. The reticle according to claim 9, wherein illumination light is illuminated from an oblique direction to improve the resolution and depth of focus of the projection optical system. Scanning exposure equipment. 12. A scanning exposure apparatus for transferring a pattern on a reticle onto a wafer while scanning a reticle on which a circuit pattern is formed and a wafer, comprising: an illumination optical apparatus for forming a predetermined illumination area on the reticle; A projection optical system that conjugates the reticle and the wafer, wherein the illumination optical device forms a plurality of light source images based on a light supply unit that supplies a light beam and the light beam from the light supply unit. An internal reflection type integrator, and a condenser optical system that forms the illumination area on the reticle based on the illumination light from the internal reflection type integrator, to improve the resolution of the projection optical system and the depth of focus.
A scanning exposure apparatus for illuminating the reticle with illumination light from an oblique direction. 13. The scanning exposure apparatus according to claim 12, further comprising a stop arranged in an optical path between an exit end of said internal reflection type integrator and said object to be irradiated. 14. The aperture stop according to claim 14, wherein said aperture stop comprises a first aperture stop having a ring-shaped aperture or a second aperture stop having a plurality of apertures eccentric to an optical axis. Scanning exposure equipment. 15. The scanning exposure apparatus according to claim 13, wherein said stop is arranged at an image forming position of a plurality of light source images by said internal reflection type integrator. 16. The apparatus according to claim 12, further comprising a condenser optical system for forming said illumination area on said reticle based on a light beam from said internal reflection type integrator. The scanning exposure apparatus according to claim 1. 17. The internal reflection type integrator and the illumination area have a rectangular shape, and the length of the rectangular illumination area in the short direction is s, and the length of the rectangular illumination area in the longitudinal direction is s. of the t, the internal reflection type integrator of the cross-section in the short side direction length of u _2, the longitudinal length of the cross section of the inside reflection type integrator when the _{v 2, s / t = u} 2 / v scanning exposure apparatus according to any one of claims 12 to 16, characterized by satisfying the _2. 18. A scanning exposure apparatus for transferring a pattern on a reticle onto a wafer while scanning a reticle on which a circuit pattern is formed and a wafer, comprising: an illumination optical apparatus for forming a predetermined illumination area on the reticle; A projection optical system that conjugates the reticle and the wafer, wherein the illumination optical device forms a plurality of light source images based on a light supply unit that supplies a light beam and the light beam from the light supply unit. An internal reflection type integrator, a condenser optical system that forms the illumination area on the reticle based on illumination light from the internal reflection type integrator, and an optical path between the internal reflection type integrator and the reticle. And a stop disposed at a position where the plurality of light source images are formed. 19. The scanning exposure apparatus according to claim 18, wherein said aperture is a plurality of apertures provided interchangeably. 20. The stop according to claim 1, wherein the stop is a first stop having a circular opening, a second stop having a ring-shaped opening, or a third stop having a plurality of openings eccentric to an optical axis. The scanning exposure apparatus according to claim 18, further comprising: 21. The illumination device according to claim 18, wherein the internal reflection type integrator and the illumination area are rectangular.
21. The scanning exposure apparatus according to any one of claims 20 to 20. 22. A scanning exposure apparatus for transferring a pattern on the reticle onto a wafer while scanning a reticle on which a circuit pattern is formed and a wafer, comprising: an illumination optical apparatus for forming a predetermined illumination area on the reticle; A projection optical system that conjugates the reticle and the wafer, wherein the illumination optical device forms a plurality of light source images based on a light supply unit that supplies a light beam and the light beam from the light supply unit. A scanning exposure apparatus, comprising: an internal reflection type integrator; and an anamorphic optical member disposed between the light supply unit and the object to be illuminated. 23. The scanning exposure apparatus according to claim 22, wherein the reticle is illuminated with illumination light in an oblique direction to improve the resolution and depth of focus of the projection optical system. 24. An illumination area is formed on a reticle on which a circuit pattern has been formed by using the scanning exposure apparatus according to claim 9, and the reticle and the wafer are moved in the scanning direction. An exposure method for transferring the circuit pattern on the reticle using the projection optical system.