JPH10163096A - Illumination system and exposure device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an optical noise so as to brightly and uniformly irradiate a mask by makign a luminous flux from a light source enter an interference- reducing member so as to provide an optical path difference to a light beam in a luminous flux for reducing interference of a luminous flux followed by irradiation on a first object. SOLUTION: In an interference-reducing member 3, when a beam 321 enters a first refraction optical element 30a, the beam 321 is influenced by the strongest power so as to go out as a light beam 321'. A light beam 32s goes out as a light beam 32c' and a light beam 32c goes out as a light beam 32c'. Three light beams 321', 32c', 32s' are condensed on a point (z). A second refraction optical element 30b has a power for returning the light beams 321', 32c', 32s' again to parallel light so as to go out in parallel as light beams 321", 32c", 32s". Thereby, optical path length become different respectively in the positions according to the positions in the (x) direction under construction so as to enter an optical integrator 4 as luminous flux with sharply reduced interference of luminous flux to an xz cross section.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination optical system and an exposure apparatus using the same, and more particularly, to an IC by projecting or scanning exposure of a circuit pattern on a mask or a reticle surface onto a wafer surface via a projection optical system. , LSI and the like.

[0002]

2. Description of the Related Art In a projection exposure apparatus for manufacturing a semiconductor device by projecting and exposing a fine pattern, the wavelength of a light source has been shortened in order to improve the resolution.
KrF excimer lasers with a wavelength of 248 nm are becoming the mainstream of light sources in terms of high brightness.

However, when the wavelength of the light source is about 300 nm or less, the glass materials usable for the optical system are limited to SiO ₂ (quartz) and CaF ₂ (fluorite) in terms of transmittance, and therefore glass materials having different wavelength dispersions. It was not possible to effectively perform achromatism by combining the above, and it was essential to reduce chromatic aberration by narrowing the bandwidth of the light source. As a result, the coherency of the light source
And optical noise due to interference has become a problem.

A technique for solving this problem is disclosed in, for example,
-092556. FIG. 9 is a schematic view of a main part of an illumination system of the exposure apparatus described in this publication. The light beam emitted from the light source 1 is converted into a desired light beam diameter by a beam shaping optical system 2, and then enters an optical integrator 4 forming a plurality of secondary light sources via an interference reducing member 3. Each of the secondary light sources passes through the condenser
Uniform illumination is achieved by Koehler illumination of (1 object) 6.

FIG. 10 is a perspective view of the interference reducing member 3. As shown in the figure, the coherence reducing member 3 is composed of a plurality of columnar prisms two-dimensionally arranged in a cross section perpendicular to the optical axis, and each of the columnar prisms is an element lens of an optical integrator. They are arranged corresponding to the optical path.

Each of the columnar prisms has a different optical path length by changing its length, and the optical path length difference is configured to be equal to or longer than the coherence length of the light source.

[0007] The illumination system using the coherence reducing member composed of the columnar prism enables illumination with suppressed optical noise due to interference even when a light source having high coherence is used.

[0008]

In recent years, in order to optically process finer patterns, a wavelength of 193 nm has been used as a light source.
The use of ArF excimer lasers has been studied, but at 193 nm wavelength, even quartz or fluorite has poor transmittance, resulting in a reduction in the glass thickness of the optical elements that make up the illumination optical system. Has become an important issue.

In this respect, the above-mentioned Japanese Patent Publication No. 07-09
In the configuration disclosed in Japanese Patent No. 2556, since the coherence reducing member is formed of a columnar prism, the thickness of the glass material of the illumination optical system increases, and the illuminance of the illumination light of the reticle decreases.

Therefore, in an exposure apparatus using an excimer laser as a light source, a coherence reducing member that does not increase the glass material thickness is essential.

An object of the present invention is to use a diffractive optical element having appropriate characteristics as a coherence reducing member to reduce the coherence of a light beam without increasing the thickness of a glass material, thereby reducing optical noise. Another object of the present invention is to provide an illumination optical system for brightly and uniformly illuminating a mask and an exposure apparatus using the same.

[0012]

According to the present invention, there is provided an illumination optical system comprising: (1-1) a light beam from a light source is made incident on an interference reducing member having at least one diffractive optical element; The first object is illuminated after reducing the coherence of the light beam by giving an optical path difference to the light beam in the light beam. (1-2) The light beam from the light source is made incident on the coherence reducing member, and the light beam in the light beam is given an optical path difference by the coherence reducing member to reduce the coherence of the light beam and enter the optical integrator. In the illumination optical system for illuminating a first object by condensing light beams from a plurality of secondary light sources formed on a plurality of element lenses constituting the optical integrator by a condenser lens, the coherence reduction is achieved. The member has at least one diffractive optical element. It is characterized by

In particular, (1-2-1) the diffractive optical element deflects the light beam only in a plane including the optical axis of the condenser lens and one direction perpendicular to the optical axis. Has,
The power distribution gives different optical path differences depending on the incident position of the light beam incident on the coherence reducing member. (1-2-2) The diffractive optical element is configured by arranging a plurality of small diffractive optical elements in the direction. (1-2-3) The small diffraction optical elements all have the same power distribution characteristics. (1-2-4) The coherence reducing member has a unit including two diffractive optical elements, and the diffractive optical element on the light incident side of the unit condenses the incident light beam in the plane, and The diffractive optical element on the light exit side of the unit converts a light beam diverging from the converging point in the plane into an emitted light beam. (1-2-5) The width of the two diffractive optical elements constituting the unit in the direction is different, and the width of the emitted light beam in the direction is changed from the width of the incident light beam. (1-2-6) The coherence reducing member has a unit including two diffractive optical elements, and the small diffractive optical element on the light incident side of the unit condenses the incident light beam in the plane,
The small diffractive optical element on the light exit side of the unit converts a light beam diverging from the converging point in the plane into an emitted light beam. (1-2-7) The unit for deflecting a light beam in a first direction perpendicular to the optical axis and the unit for deflecting a light beam in a second direction orthogonal to the optical axis and the first direction. Have. (1-2-8) The power distribution of the diffractive optical elements constituting the unit for deflecting the light beam in the first direction and the unit for deflecting the light beam in the second direction is controlled by controlling the power distribution.
The coherence of the light beam in one direction and the second direction is controlled. (1-2-9) A plurality of units for deflecting light rays in the first direction and a plurality of units for deflecting light rays in the second direction are arranged side by side in the optical axis direction. It is characterized by

Further, the illumination device of the present invention is characterized by including the illumination optical system according to any one of (1-3) (1-1) to (1-2-9). .

Further, the exposure apparatus of the present invention has an illuminating device according to (1-4) or (1-3), and forms a light beam from the first object on a second object by a projection optical system. And expose. (1-5) The illumination device according to the above (1-3), wherein the first object is projected onto a second object by a projection optical system.
Both the object and the second object are scanned and exposed in a direction perpendicular to the optical axis of the projection optical system at a speed ratio corresponding to the projection magnification of the projection optical system. It is characterized by

In the method of manufacturing a device according to the present invention, there is provided: (1-6) the first object is projected by the projection optical system using the exposure apparatus described in (1-4) or (1-5). (2) After projecting and exposing on an object, the second object is developed to manufacture a device.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view showing a main part of an exposure apparatus according to a first embodiment of the present invention. In the present embodiment, the optical axis between the condenser lens and the projection lens
z Illustrated with rectangular coordinates. FIG. 1A is an xz cross-sectional projection view, and FIG. 1B is a yz cross-section projection view. Note that the direction of the x-axis is referred to as a first direction, and the direction of the y-axis is referred to as a second direction.

In FIG. 1, reference numeral 1 denotes a light source, which is constituted by an excimer laser. Reference numeral 2 denotes a beam shaping optical system, which is a so-called beam expander, which enlarges a light beam emitted from the light source 1 to a desired size.

Reference numeral 30a denotes a first diffractive optical element, which deflects the incident light beam only in a plane including the optical axis and the first direction.
It has power (deflects only in the x direction), but the amount of deflection depends on the position of the light beam in the x direction. That is,
In FIG. 1 (A), the uppermost end has the maximum power, the lowermost end has no power, and the middle has a continuously changing power. At the point z _x of

FIG. 2 is an xz sectional view of the diffractive optical element 30a, and FIG. 3 is a front view thereof (xy plane projection view). Since the diffractive optical element 30a has a power that deflects only in the x direction, the diffractive optical element 30a has a linear pattern array in the y direction as shown in FIG. The arrangement is coarsest at the bottom in FIGS. 2 and 3, and is arranged densely to increase the power upward.

Although FIG. 2 is drawn in a blazed shape for the sake of simplicity, in an actual configuration, it is preferable to manufacture the device as a binary device using lithography technology. Four or more levels are preferred.

The diffractive optical element in the following specification basically conforms to the above-described configuration, and is configured by a linear pattern orthogonal to the direction of power.

Numeral 30b denotes a second diffractive optical element which deflects the incident light beam only in the x direction, but the amount of deflection of the light beam is
It differs depending on the position in the x direction.In FIG. 1 (A), there is no power at the uppermost end, the maximum power at the lowermost end, and the power that changes continuously in the middle, In (A), the light flux divergently incident from the point z _x is converted into parallel light.

Reference numeral 31a denotes a third diffractive optical element, which deflects the incident light beam only in a plane including the optical axis and the second direction.
(deflect only in the y direction), but the amount of deflection is
Depends on the position of the direction. That is, in FIG. 1 (B), the uppermost end has the maximum power, the lowermost end has no power, and the middle has a continuously changing power. ) Focus on the point z _y in the middle.

Reference numeral 31b denotes a fourth diffractive optical element, which deflects the incident light beam only in the y direction, but the amount of deflection of the light beam is
It differs depending on the position in the y direction.In FIG. 1 (B), there is no power at the uppermost end, the maximum power at the lowermost end, and the power that changes continuously in the middle, converted into parallel light light beam divergently incident from point z _y in (B).

The first diffractive optical element 30a and the second diffractive optical element
The reference numeral 30b, the third diffractive optical element 31a, the fourth diffractive optical element 31b, and the like constitute one element of the coherence reducing member 3.

First diffractive optical element 30a, second diffractive optical element
30b and the like constitute the first unit 30A. Further, the third diffractive optical element 31a, the fourth diffractive optical element 31b, etc. constitute a second unit 31A.

4 is an optical integrator,
It is composed of many columnar lenses (element lenses),
A secondary light source is formed in each element lens from the incident light beam. Five
Is a condenser lens, which refracts a light beam emitted from each secondary light source of the optical integrator 4 and superimposes and condenses it on an illuminated object (first object) 6 to illuminate it. The illuminated object 6 is a circuit pattern on the reticle.

Reference numeral 7 denotes a projection lens (projection optical system) which forms an image of a circuit pattern on the reticle 6 on a photosensitive substrate (wafer, second object) 8.

The light source 1, the beam shaping optical system 2, the coherence reducing member 3, the optical integrator 4, the condenser lens 5, and the like constitute one element of the illumination optical system.

The operation of this embodiment will be described. The light beam emitted from the light source 1 is converted into a desired light beam diameter by a beam shaping optical system 2, and then enters an optical integrator 4 via a coherence reducing member 3 to form a number of secondary light sources. Each secondary light source illuminates the illuminated object (circuit pattern) 6 through a condenser lens 5 in a color manner.

As a result, the circuit pattern on the reticle is imaged on the photosensitive substrate 8 by the projection lens 7 and exposure is performed.

The operation of the interference reducing member 3 will be described in more detail. 1 from the light beam incident on the first diffractive optical element 30a.
In (A), the rays incident on the top, middle, and bottom are 32
l, 32c, 33s. The light beam 32l is emitted as a light beam 32l 'under the influence of the strongest power. The light beam 32s goes straight without being refracted and emerges as a light beam 32s'. The light beam 32c is emitted as a light beam 32c 'under the influence of the intermediate power. Three
The two rays converge on point z _x .

The second diffractive optical element 30b receives light beams 32l ', 32c',
It has the power characteristic of returning 32s' to parallel light again.
The light beam 321 'is emitted in parallel as a light beam 321 ", the light beam 32c' is emitted in a light beam 32c", and the light beam 32s' is emitted in a light beam 32s ".

With the above arrangement, the light beams 32s, 33c, 33l
Goes through the first and second diffractive optical elements 30a and 30b, so that the optical path lengths are different at positions in the x direction in the light beam,
With respect to the xz section, the light beam is incident on the optical integrator 4 as a light beam in which the coherence of the light beam is greatly reduced.

The same path is followed in the yz section projection view of FIG. 1 (B). That is, the third diffractive optical element 31a converts the three parallel light beams 331, 33c, and 33s incident thereon into one point shown in FIG.
The rays are converted into rays 33l ', 33c', and 33s' converged on z _y .

Next, the fourth diffractive optical element 31b returns the rays 33l ', 33c', 33s' emitted from the third diffractive optical element 31a to parallel rays 331 ", 33c", 33s "again.

With the above arrangement, the light beams 33l, 33c, 33s
After passing through the diffractive optical elements 31a and 31b, the optical path lengths are different at the positions in the y direction in the light beam, and the light beam becomes a light beam in which the coherence of the light beam is greatly reduced with respect to the yz section. −4.

Therefore, the diffractive optical elements on the light incident side of the first and second units 30A and 31A condense the light beam incident on each unit in a plane including the optical axis and the x direction or the y direction. The diffractive optical element on the light exit side of the unit changes the light flux diverging from each focusing point in each plane into an emitted light flux.

Then, the four diffractive optical elements 30a, 30b,
After passing through 31a and 31b, the optical integrator
The optical path length of the light beam incident on the element lens of No. 4 can be varied greatly depending on the position of the xy section.

As described above, in the present embodiment, the same effect as that of the conventional coherence reducing member composed of a collection of columnar prisms can be obtained. However, in the present embodiment, only four plate-like diffractive optical elements are used. Therefore, when illuminating the circuit pattern without increasing the thickness of the glass material, it is possible to achieve bright and uniform illumination without optical noise due to interference.

In the present embodiment, the x-direction coherence and the y-direction coherence can be adjusted by making the power distribution in the first unit 30A different from the power distribution in the second unit 31A. And the difference in uniformity of illumination between the scanning direction and the non-scanning direction in slit scan exposure for synchronously moving the reticle and the wafer 8 relative to the illumination area. Can be dealt with.

In this embodiment of the exposure apparatus, a plurality of lenses formed on the element lens of the optical integrator 4 are formed.
The luminous flux from the secondary light source is directly condensed on the circuit pattern (first object) by the condenser lens 5 and illuminated.In some cases, the luminous flux from the secondary light source is focused on the condenser lens, aperture stop, and aperture image. The circuit pattern is illuminated through the lens. The condenser lens and the aperture imaging lens in such a case are one element of the condenser lens referred to in this specification.

FIG. 4 is a schematic view of a main part of a coherence reducing member according to a second embodiment of the exposure apparatus of the present invention. FIG. 4A is an xz cross-sectional projection view, and FIG. 4B is a yz cross-section projection view. This embodiment is different from the first embodiment only in the configuration of the coherence reducing member, and the other parts are the same as the first embodiment.

In the figure, 40a is the first diffractive optical element, and 40b is the first diffractive optical element.
2 Diffractive optical element. Each operation is the first of the first embodiment.
This is the same as that of the diffractive optical element 30a and the second diffractive optical element 30b. First diffractive optical element 40a and second diffractive optical element
40b constitutes a first unit 40A for reducing coherence in the x direction.

Reference numeral 41a denotes a third diffractive optical element, and 41b denotes a fourth diffractive optical element.
It is a diffractive optical element. The respective operations are the same as those of the third diffractive optical element 31a and the fourth diffractive optical element 31b of the first embodiment. Third diffractive optical element 41a and fourth diffractive optical element 41
b constitutes a second unit 41A for reducing coherence in the y direction.

Then, two first units 40A are arranged in the optical axis direction upside down in the xz section, and two second units 41A are arranged in the optical axis direction upside down in the yz section. ing.

The two first units 40A, the two second units 41A, and the like constitute one element of the interference reducing member 3.

In the xz sectional projection of this embodiment, the second first unit 40A is arranged upside down with respect to the first first unit 40A in the drawing along the traveling direction of light, and the yz sectional projection is taken. But the second 2nd unit 41A is replaced with the first 2nd unit
41A is arranged upside down in the figure, whereby the optical axis of the light beam incident on the coherence reducing member 3 and the optical axis of the light beam emitted from the coherence reducing member 3 are aligned.

In the present embodiment, since the optical path difference is further increased in accordance with the position of the light beam in the xy section than in the first embodiment, the coherence of the light beam is further reduced as compared with the first embodiment, and the optical characteristics are further improved than the first embodiment. An illumination state with less noise can be obtained.

As described above, by arranging the first unit 40A as one unit and arranging three or more units in series, it is possible to further reduce the light beam coherence in the xz section.

Similarly, by using the second unit 41A as one unit and arranging three or more units in series, it is possible to further reduce the coherence of the light beam in the yz section.

FIG. 5 is a schematic view of a main part of a third embodiment of the exposure apparatus of the present invention. FIG. 5A is an xz cross-sectional projection view, and FIG.
Is a yz section projection view. In this embodiment, the beam shaping optical system 2 of the first embodiment is deleted, the configuration of the coherence reducing member 3 is changed, and the function of the beam shaping optical system is provided therein. Same as mode 1.

In the figure, reference numeral 50a denotes a first diffractive optical element, which has a power to deflect an incident light beam only in the x direction, but the amount of deflection depends on the position of the light beam in the x direction. That is, in FIG. 5 (A), the uppermost end has the maximum power, the lowermost end has no power, and the middle has a continuously changing power. Focus on the point z _x in the middle.

Reference numeral 50b denotes a second diffractive optical element, which deflects the incident light beam only in the x direction, but the amount of deflection of the light beam is
It differs depending on the position in the x direction, and in FIG. 5 (A), there is no power at the uppermost end, it has the maximum power at the lowermost end, and it has power that changes continuously in the middle, In (A), the light flux divergently incident from the point z _x is converted into parallel light.
At this time, the light beam a second diffractive optical element 50b is to be divergently incident from the point z _x are disposed at a position a desired width, optical integrators a narrow light beam thereby emitted from the light source 1 - cover motor 4 Has been converted to width.

Reference numeral 51a denotes a third diffractive optical element which deflects the incident light beam only in the y direction, but the amount of deflection of the light beam is
Depends on the position in the y direction. That is, in FIG. 5B, the uppermost end has the maximum power, the lowermost end has no power, and the middle has a continuously changing power. ) Focus on the point z _y in the middle.

Reference numeral 51b denotes a fourth diffractive optical element which deflects the incident light beam only in the y direction, but the amount of deflection of the light beam is
In FIG. 5 (B), there is no power at the uppermost end, the maximum power at the lowermost end, and the power that changes continuously in the middle of FIG. converted into parallel light light beam divergently incident from point z _y in (B).
In this case, the light flux fourth diffractive optical element 51b is to be divergently incident from the point z _y are arranged at positions a desired width, optical integrators a narrow light beam thereby emitted from the light source 1 - cover motor 4 Has been converted to width.

The first diffractive optical element 50a and the second diffractive optical element
The reference numeral 50b, the third diffractive optical element 51a, the fourth diffractive optical element 51b, and the like constitute one element of the coherence reducing member 3. Also, light source
Each element from 1 to the condenser lens 5 constitutes one element of the illumination optical system.

The first diffractive optical element 50a and the second diffractive optical element
50b and the like constitute the first unit 50A. The third diffractive optical element 51a, the fourth diffractive optical element 51b, and the like constitute a second unit 51A.

The function of the coherence reducing member 3 of the present embodiment is basically the same as that of the first embodiment, although the size of the diffractive optical element is different.

In this embodiment, the beam shaping optical system conventionally provided as another member becomes unnecessary, and the thickness of the glass material can be reduced.

FIG. 6 is a schematic view of a main part of an interference reducing member according to a fourth embodiment of the exposure apparatus of the present invention. FIG. 6 (A) is an xz cross-sectional projection view, and FIG. 6 (B) is a yz cross-section projection view. This embodiment is different from the first embodiment only in the configuration of the interference reducing member, and the other parts are the same as the first embodiment.

In the figure, reference numeral 60a denotes a first diffractive optical element which is a member for reducing the coherence in the x direction, and comprises a plurality of small diffractive optical elements 600a having the same power distribution characteristics arranged in the x direction. 60b is a second diffractive optical element which is a member for reducing coherence in the x direction, and has a plurality of small diffractive optical elements 600b having the same power distribution characteristics (the width in the x direction is the same as the small diffractive optical element 600a) Are arranged side by side in the x direction.

The small diffractive optical element 600a has the power to deflect the incident light beam only in the x direction, but the amount of deflection varies depending on the position of the light beam in the x direction. That is, each small diffractive optical element 600a in FIG. 6 (A) has the maximum power at the uppermost end, has no power at the lowermost end, and has a continuously changing power in the middle. For example, in the case of the small diffractive optical element 600a surrounded by a dotted line in FIG.
The light is focused on a point z _xB in 6 (A).

The small diffractive optical element 600b deflects the incident light beam only in the x direction, but the amount of deflection differs depending on the position of the light beam in the x direction. That is, each small diffractive optical element 600b in FIG. 6 (A) has no power at the uppermost end, has the maximum power at the lowermost end, and has a continuously changing power in the middle. For example, in the case of the small diffractive optical element 600b surrounded by a dotted line in FIG. 6A, the light beam divergently incident from the point z _xB in FIG. _6A is converted into parallel light.

Reference numeral 61a denotes a third diffractive optical element which is a member for reducing the coherence in the y direction, and is constituted by arranging a plurality of small diffractive optical elements 601a having the same power distribution characteristic in the y direction. Reference numeral 61b denotes a fourth diffractive optical element which is a member for reducing the coherence in the y direction, and has a plurality of small diffractive optical elements 601b (the width in the y direction is
601a) are arranged in the y direction.

The small diffractive optical element 601a has a power to deflect the incident light beam only in the y direction, but the amount of deflection varies depending on the position of the light beam in the y direction. That is, each small diffraction optical element 601a in FIG. 6B has the maximum power at the uppermost end, has no power at the lowermost end, and has a continuously changing power in the middle. For example, in the case of the small diffraction optical element 601a surrounded by a dotted line in FIG.
The light is focused on a point z _yB in 6 (B).

The small diffractive optical element 601b has the power to deflect the incident light beam only in the y direction, but the amount of deflection varies depending on the position of the light beam in the y direction. The element 601b has no power at the uppermost end, has maximum power at the lowermost end, and has power that changes continuously in the middle, for example, surrounded by a dotted line in FIG. In the case of the small diffractive optical element 601b, the point z _yB in FIG.
The divergent incident light beam is converted into parallel light.

The first diffractive optical element 60a and the second diffractive optical element
The reference numeral 60b, the third diffractive optical element 61a, the fourth diffractive optical element 61b, and the like constitute one element of the coherence reducing member 3. Also, the first
The diffractive optical element 60a, the second diffractive optical element 60b, and the like constitute a first unit 60A. Also, the third diffractive optical element 61a,
The fourth diffractive optical element 61b and the like constitute a second unit 61A.

The four diffractive optical elements 60a, 60b,
61a and 61b are formed by arranging a number of the same small diffractive optical elements as described above, so that even those having a large area can be easily manufactured.

Since the coherence of the emitted light beam differs depending on the width of the entrance aperture of the small diffraction optical elements 600a and 601a, it is desirable to set the width of the entrance aperture by simulation, actual measurement, or the like.

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

FIG. 7 is a flowchart of a method of manufacturing a device (a semiconductor chip such as an IC or an LSI, or a liquid crystal panel or a CCD) according to the present invention. This will be described. In step 1 (circuit design), the circuit of the semiconductor device is designed. Step 2 (mask fabrication) forms a mask on which the designed circuit pattern is formed. On the other hand, in step 3 (wafer manufacturing), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is referred to as a pre-process, and an actual circuit is formed on the wafer by lithography using the prepared mask (reticle), the wafer, and the exposure apparatus of the present invention. Step 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer prepared in step 4, and includes processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). . In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 5 are performed. Through these steps, the semiconductor device is completed and shipped (Step 7
) Is done.

FIG. 8 is a detailed flowchart of the wafer process. Step 11 (oxidation) oxidizes the wafer's surface. Step 12 (CVD) forms an insulating film on the wafer surface. Step 13 (electrode formation) forms electrodes on the wafer by vapor deposition. Step 14 (ion implantation) implants ions into the wafer. In step 15 (resist processing), a photosensitive agent is applied to the wafer. Step 16
In (exposure), the circuit pattern of the reticle is printed and exposed on the wafer by the exposure apparatus of the present invention. Step 17 (Development)
Then, the exposed wafer is developed. Step 18 (etching) removes portions other than the developed resist. In step 19 (resist stripping), the unnecessary resist after etching is removed.

By repeating these steps, multiple circuit patterns are formed on the wafer.

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

[0077]

According to the present invention, a diffractive optical element having appropriate characteristics is used for the coherence reducing member.
By reducing the coherence of the luminous flux without increasing the thickness of the glass material,
An illumination optical system that illuminates a mask brightly and uniformly by reducing optical noise and an exposure apparatus using the same are achieved.

By providing the function of the beam shaping optical system to the coherence reducing member, an illumination optical system with a smaller glass material thickness and an exposure apparatus using the same can be achieved.

Further, the use of the exposure apparatus of the present invention achieves a device manufacturing method capable of easily manufacturing a highly integrated semiconductor device which has conventionally been difficult to manufacture.

[Brief description of the drawings]

FIG. 1 is a schematic view of a main part of an exposure apparatus according to a first embodiment of the present invention.

FIG. 2 is an xz sectional view of the diffractive optical element 30a.

FIG. 3 is a front view of a diffractive optical element 30a.

FIG. 4 is a schematic diagram of a main part of a coherence reducing member according to a second embodiment of the exposure apparatus of the present invention.

FIG. 5 is a schematic diagram of a main part of an exposure apparatus according to a third embodiment of the present invention.

FIG. 6 is a schematic diagram of a main part of an interference reducing member according to a fourth embodiment of the exposure apparatus of the present invention.

FIG. 7 is a flowchart of a device manufacturing method of the present invention.

FIG. 8 is a detailed flowchart of a wafer process.

FIG. 9 is a schematic diagram of a main part of an illumination system of a conventional exposure apparatus.

FIG. 10 is a perspective view of a conventional interference reducing member.

[Explanation of symbols]

 1 Light source 2 Beam shaping optical system 3 Interference reducing member 4 Optical integrator 5 Condenser lens 6 Mask (reticle) 7 Projection lens 8 Wafer 30a, 40a, 50a, 60a First diffractive optical element 30b, 40b, 50b, 60b Second diffractive optical element 31a, 41a, 51a, 61a Third diffractive optical element 31b, 41b, 51b, 61b Fourth diffractive optical element 600a, 600b, 601a, 601b Small diffractive optical element 30A, 40A, 50A, 60A First Unit 31A, 41A, 51A, 61A 2nd unit

Claims (15)

[Claims] 1. A light beam from a light source is incident on a coherence reducing member having at least one diffractive optical element, and the coherence reducing member gives a light path difference to a light beam in the light beam to reduce the coherence of the light beam. An illumination optical system for illuminating a first object after the illumination. 2. A light beam from a light source is made incident on a coherence reducing member, and the light beam in the light beam is given an optical path difference by the coherence reducing member to reduce the coherence of the light beam and is made incident on an optical integrator. An illumination optical system for illuminating a first object by condensing light beams from a plurality of secondary light sources formed on a plurality of element lenses constituting the optical integrator by a condenser lens, wherein: An illumination optical system, wherein the member has at least one diffractive optical element. 3. The diffractive optical element has a power distribution for deflecting the light beam only in a plane including an optical axis of the condenser lens and one direction perpendicular to the optical axis, and the power distribution. 3. The illumination optical system according to claim 2, wherein a different optical path difference is provided depending on the incident position of the light beam incident on the coherence reducing member. 4. The illumination optical system according to claim 3, wherein said diffractive optical element comprises a plurality of small diffractive optical elements arranged in said direction. 5. The illumination optical system according to claim 4, wherein all of said small diffractive optical elements have the same power distribution characteristics. 6. The coherence reducing member has a unit composed of two diffractive optical elements, and the diffractive optical element on the light incident side of the unit condenses an incident light beam in the plane, and 4. The illumination optical system according to claim 3, wherein the diffractive optical element on the light exit side changes a light beam diverging from the converging point in the plane into an emitted light beam. 7. The width of the two diffractive optical elements constituting the unit in the direction is different, and the width of the emitted light beam in the direction is changed from the width of the incident light beam. Item 6. The illumination optical system according to Item 6. 8. The coherence reducing member has a unit composed of two diffractive optical elements, and the small diffractive optical element on the light incident side of the unit condenses an incident light beam in the plane, and 6. The illumination optical system according to claim 4, wherein said small diffractive optical element on the light exit side converts a light beam diverging from said converging point into an emitted light beam in said plane. 9. A unit for deflecting a light beam in a first direction perpendicular to the optical axis, and the unit for deflecting a light beam in a second direction orthogonal to the optical axis and the first direction. The illumination optical system according to any one of claims 6 to 8, wherein: 10. The power distribution of the diffractive optical element constituting each of a unit for deflecting a light beam in the first direction and a unit for deflecting a light beam in the second direction is controlled by controlling a power distribution of the diffractive optical element.
10. The illumination optical system according to claim 9, wherein coherence of a light beam in one direction and the second direction is controlled. 11. The apparatus according to claim 9, wherein a plurality of units for deflecting the light beam in the first direction and a plurality of units for deflecting the light beam in the second direction are arranged in the optical axis direction. 10 illumination optical systems. 12. An illumination device comprising the illumination optical system according to claim 1. Description: 13. The lighting device according to claim 12, further comprising:
1. An exposure apparatus, wherein a light beam from an object is imaged on a second object by a projection optical system and exposed. 14. The lighting device according to claim 12, wherein
(1) An object is projected onto a second object by a projection optical system, and both the first object and the second object are made to correspond to the projection magnification of the projection optical system in a direction perpendicular to the optical axis of the projection optical system. An exposure apparatus for scanning and exposing in synchronization with a speed ratio. 15. A device is manufactured by projecting and exposing the first object onto the second object by the projection optical system using the exposure apparatus according to claim 13 or 14. A method for manufacturing a device, comprising: