JP2002075859A - Illumination system, exposure system and method for manufacturing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illumination system by which a pattern of a reticle can be projected onto a wafer with a high degree of accuracy. SOLUTION: With respect to the illumination system having an optical system which makes a light flux from a light source incident onto a multi-light-flux forming means and a lens system which illuminates a surface to be illuminated by the multiple fluxes formed by the multi-light-flux forming means, the optical system has, from the side of the multi-light-flux forming means in sequence, an illumination optical system and a first light deflecting member provided at the front focal point of the illumination optical system or in its proximity and the multi-light-flux forming means is provided with a light axis of the illumination optical system and a plurality of fine lenses which are placed around the light axis. The first light deflecting member is provided with a plurality of transparent wedges which are rotatable about the light axis of the illumination optical system and the incoming position of the whole light fluxes from the light surface to the multi-light-flux forming means is changed by changing the direction of deflection of the whole light fluxes from the light source by the rotation of the plurality of transparent wedges.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination device, an exposure device, and a device manufacturing method, and more particularly to a semiconductor device such as an LSI, an imaging device such as a CCD, a display device such as a liquid crystal panel, and a detection device such as a magnetic head. The present invention relates to an illumination apparatus, an exposure apparatus, and a device manufacturing method for appropriately illuminating a device pattern on a reticle surface when manufacturing various devices.

[0002]

2. Description of the Related Art In recent years, the progress of fine processing technology has been remarkable, and the resolution required in lithography has been increased to 0.3 μm or 0.2 μm.
A very fine one of 5 μm is required.

[0003] The applicant of the present invention has disclosed in Japanese Patent Application Laid-Open No. 5-28331.
Japanese Patent Application Laid-Open No. H07-207 proposes an illumination device that can improve the resolution of a projection exposure apparatus for lithography.

FIG. 4 shows an illumination apparatus (projection exposure apparatus) disclosed in Japanese Patent Application Laid-Open No. 5-283317.

[0005] In FIG. 4, reference numeral 1 denotes a high-brightness ultra-high pressure mercury lamp that emits ultraviolet rays or far ultraviolet rays.
Is near the first focal point of the elliptical mirror-2. The light emitted from the mercury lamp 1 is reflected and condensed by the elliptical mirror-2, is reflected by the cold mirror-3, and is then imaged by the light emitting unit 1a (light emitting unit) near the second focal point 4 of the elliptical mirror-2. (Image) 1b is formed. Cold mirror-3 is formed by forming a multilayer film on a glass substrate that transmits infrared light and reflects ultraviolet light.

Reference numeral 101 denotes an imaging system composed of lens systems 5 and 9, and a light emitting unit image 1 formed near the second focal point 4.
b is the light incident surface 10a of the optical integrator 10.
The image is roughly formed above. The lens system 9 is a zoom lens, and has a configuration in which the magnification of the imaging system 101 can be changed. Reference numeral 7 denotes an optical element holding member, which is configured so that a plurality of optical elements such as a conical prism and a polygonal pyramid prism can be switched and arranged in the optical path. Lens system 5
Makes the position of the opening of the elliptical mirror-2 and the position of the holding member 7 optically substantially conjugate to each other.

The optical integrator 10 is a multi-beam forming member for forming a large number of light beams. The optical integrator 10 is formed by arranging a large number of minute lenses two-dimensionally along a plane perpendicular to the optical axis. A secondary light source 10c is formed near the surface 10b. Reference numeral 11 denotes a diaphragm member having a plurality of aperture members having different shapes and sizes from each other. The diaphragm member 11 has a mechanism capable of switching an aperture member inserted into an optical path.

Reference numeral 14a denotes a lens system.
Collects the light beam from the light exit surface 10b of the optical integrator 10. A condensing lens system 14 including a lens system 14a and a collimator lens 14b is a light beam from a light exit surface 10b via an aperture member 11 and a mirror 13, and is a light-receiving surface mounted on a reticle stage 16. A certain reticle 15 is illuminated with a color light.

Reference numeral 17 denotes a projection optical system, and the reticle 15
Is reduced and projected on the photosensitive surface of the wafer 18 placed on the wafer chuck 19. 20 is
A stage on which a wafer chuck 19 is mounted. The secondary light source 10c near the light exit surface 10b of the optical integrator 10 forms an image near the pupil 17a of the projection optical system 17 by the condenser lens system 14.

The illuminating device shown in FIG. 4 rotates the optical element holding member 7 in accordance with the directionality of the fine pattern drawn on the reticle 15, the resolution line width, and the like. By inserting a desired optical element into the optical path and changing the magnification of the image forming system 101 as necessary, FIG.
As shown in (B) and (C), the light intensity distribution on the light incident surface 10a of the optical integrator 10 is changed to 2
The light intensity distribution (illumination method) of the secondary light source is changed. FIG.
The hatched portion in the middle is a region where the light intensity is high.

[0011]

In the above-mentioned illumination device, the shape and size of the aperture of the diaphragm member 11 are changed, the optical element held by the holding member 7 is switched, and the imaging system 1 is used.
If the imaging magnification of 01 is changed, the illumination state on the reticle 15 or the wafer 18 changes, and it becomes impossible to project the reticle pattern onto the wafer with high accuracy. An object of the present invention is to provide an illumination apparatus, an exposure apparatus, and a device manufacturing method that can reduce this kind of deterioration in projection accuracy.

[0012]

In order to achieve the above object, an illuminating apparatus according to the present invention comprises an optical system for causing a light beam from a light source to enter an optical integrator, and a multi-beam formed by the optical integrator to illuminate a surface to be illuminated. The optical integrator and the first light deflecting member are arranged on the optical axis of the optical system, and a first transparent wedge and a second transparent wedge as the first light deflecting member are illuminated. The wedges have substantially the same wedge angle, are individually rotatable around the optical axis, and are rotated by the first wedge and the second wedge.
The position of incidence of the light beam from the light source on the optical integrator is changed.

[0013] The first light polarizing member may deflect the light beam incident on the first light polarizing member in a desired direction at a desired angle.

The optical system has an irradiation optical system between the optical integrator and the first light deflecting member, and the light deflecting member is arranged at a front focal position of the irradiation optical system. It is characterized by.

Further, the optical system has an irradiation optical system between the optical integrator and the first light deflecting member, and the optical integrator is disposed at a rear focal position of the irradiation optical system. It is characterized by.

Further, the first light deflecting member is provided with two transparent wedges.

Further, the first light deflecting member is provided with three transparent wedges. In addition, the transparent 3
Each wedge is characterized in that the wedge angle of the wedge having the largest wedge angle is smaller than the sum of the wedge angles of the other two wedges.

A second beam splitting device for splitting the light beam from the light source into a plurality of light beams and deflecting the plurality of light beams in mutually different directions so that the plurality of light beams enter different positions of the optical integrator; A light deflecting member is provided near the first light deflecting member.

A second light deflecting member having a conical deflecting surface for converting a light beam from the light source into a ring-shaped light beam and irradiating the light to the optical integrator is provided near the first light deflecting member. It is characterized by having.

Further, the invention is characterized in that the second light deflecting member is provided between the first light deflecting member and the irradiation optical system.

A reticle and a wafer are illuminated by the multi-beam. Further, the optical system includes an elliptical mirror.

13. The lighting device according to claim 1, wherein the light source includes a mercury lamp.

Further, the wedge has at least one surface inclined with respect to the optical axis of the irradiation optical system.

[0024] The exposure apparatus may further comprise:
A mask is illuminated by any one of the illumination devices according to item 4, and the pattern of the illuminated mask is projected onto a wafer by a projection optical system.

Further, the device manufacturing method includes a step of exposing the wafer with a device pattern by the exposure apparatus according to claim 15 and a step of developing the exposed wafer.

[0026]

FIG. 1 is a diagram showing a first embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a high-intensity ultra-high pressure mercury lamp that emits ultraviolet light or far ultraviolet light, and a light emitting portion 1a of the mercury lamp 1
Is near the first focal point of the elliptical mirror-2. The light emitted from the mercury lamp 1 is reflected and condensed by the elliptical mirror-2, is reflected by the cold mirror-3, and is then imaged by the light emitting unit 1a (light emitting unit) near the second focal point 4 of the elliptical mirror-2. (Image) 1b is formed. Cold mirror-3 is formed by forming a multilayer film on a glass substrate that transmits infrared light and reflects ultraviolet light. Mercury lamp 1
Can be moved in the direction of the optical axis. For example, the position in the direction of the optical axis can be adjusted so that the amount of the light beam incident on the light incident surface 10a of the optical integrator 10 is maximized.

Reference numeral 101 denotes an optical system such as an image forming system including the lens systems 5 and 9. The light emitting unit image 1 b formed in the vicinity of the second focal point 4 is formed on the light incident surface 10 a of the optical integrator 10. Or it is imaged again near it. The front focal position of the lens system 5 substantially coincides with the position of the light emitting unit image 1b formed near the second focal point 4. The lens system 9 (irradiation optical system) is a zoom lens, and has a configuration in which the magnification of the imaging system 101 can be changed. Reference numeral 7 denotes a holding member for the optical element, which is configured so that a plurality of optical elements (second light deflecting members) such as a conical prism and a polygonal pyramid prism can be switched and arranged in the optical path. Lens system 5
The (light receiving optical system) makes the position of the opening of the elliptical mirror-2 and the position of the holding member 7 optically substantially conjugate with each other. FIG. 2 shows a holding member 7 and a plurality of optical elements 6 held thereon.
a to 6f, the holding member 7 is a turret plate that rotates around a rotation axis passing through the center by a motor (not shown), the optical element 6a is a conical prism, and the optical element 6b is more apical than the optical element 6a. Is a conical prism, the optical element 6c is a quadrangular pyramid prism, the optical element 6d is a quadrangular pyramid prism having a larger apex angle than the optical element 6c, the optical element 6e is an octagonal pyramid prism, and the optical element 6f is a parallel flat plate. Opening is also acceptable.)

The optical integrator 10 is a multi-beam forming member for forming a large number of light beams, and is formed by arranging a large number of minute lenses two-dimensionally along a plane perpendicular to the optical axis. A secondary light source 10c is formed near the surface 10b. The light incident surface of the optical integrator 10 is located at the rear focal position of the lens system 9. Reference numeral 11 denotes a diaphragm member having a plurality of aperture members having different shapes and sizes from each other. The diaphragm member 11 has a mechanism capable of switching an aperture member inserted into an optical path. The aperture shapes of the plurality of aperture members correspond to the optical elements 6a to 6f, and are ring-shaped,
Includes one hole, eight holes, and one hole.

Reference numeral 14a denotes a lens system.
Collects the light beam from the light exit surface 10b of the optical integrator 10. A condensing lens system 14 including a lens system 14a and a collimator lens 14b is a light beam from a light exit surface 10b via an aperture member 11 and a mirror 13, and is a light-receiving surface mounted on a reticle stage 16. A certain reticle 15 is illuminated with a color light.

Reference numeral 17 denotes a projection optical system, and the reticle 15
Is reduced and projected on the photosensitive surface of the wafer 18 placed on the wafer chuck 19. 20 is
An XY stage on which a wafer chuck 19 is mounted. The secondary light source 10c near the light exit surface 10b of the optical integrator 10 forms an image near the pupil 17a of the projection optical system 17 by the condenser lens 14.

The illuminating apparatus shown in FIG. 1 rotates the optical element holding member 7 in accordance with the directionality of the fine pattern drawn on the reticle 15, the resolution line width, and the like, thereby forming a plurality of optical elements 6a to 6f. 6 by inserting a desired optical element in the optical path and changing the magnification of the imaging system 101 as necessary.
As shown in (A), (B) and (C), the light intensity distribution on the light incident surface 10a of the optical integrator 10 is changed to change the light intensity distribution (illumination method) of the secondary light source. I have. The hatched portion in FIG. 6 is a region where the light intensity is high.

A feature of the illumination device shown in FIG. 1 is that an optical axis adjusting device 21 (first light deflection member) is provided near the optical element holding member 7. The optical axis adjusting device 21 includes two wedge glasses 21a and 21b having substantially the same wedge angle, and the two wedge glasses 21a and 21b are both provided on a first surface perpendicular to the optical axis and on the optical axis. A second surface inclined with respect to the first surface. The wedge angle refers to an angle formed between the first surface and the second surface. The optical axis adjusting device 21 rotates each of the wedge glasses 21a and 21b individually using a driving device (not shown) with the optical axis as a rotation axis, and adjusts the rotation angle around each optical axis. By this adjustment, the entire light beam passing through the optical axis adjusting device 21 can be deflected in a desired direction by an angle, and the incident position of the entire light beam on the light incident surface 10a of the optical integrator 10 is changed to change the position on the light incident surface 10a. The entire light intensity distribution can be moved.

In the illumination apparatus shown in FIG. 1, when the position of the entire light beam (entire light intensity distribution) incident on the optical integrator 10 is changed, the illumination state on the reticle 15 or the wafer 18 which is the surface to be illuminated changes. In this embodiment, utilizing this fact, the rotation angles of the wedge glasses 21a and 21b are adjusted so that the reticle pattern can be projected onto the wafer with high accuracy.

FIG. 3 is an explanatory diagram showing the function of the optical axis adjusting device 21. FIG. 3A is a diagram showing a case where the parallel flat plate 6f is inserted in the optical path and the two wedge glasses 21a and 21b are set at positions where the wedge angles cancel each other.
FIG. 3B shows the wedge glass 21b from the state of FIG.
Is a diagram showing a case where is rotated by a certain angle. FIG.
FIGS. 3A and 3B schematically show the light intensity on the light incident surface 10a of the optical integrator 10, and show that each of the wedge glasses 21a and 21b has an appropriate angle. The optical integrator 1 is rotated to deflect the entire light beam in a desired direction by an angle.
The light intensity distribution on the 0 light incident surface 10a is represented by the optical axis (center).
It can be seen that eccentricity can be achieved. This is because when the incident angle of the entire light beam incident on the lens system 9 is changed, the light incident surface 1 of the optical integrator 10 of the entire light beam is changed.
This is because the position of incidence on 0a changes.

Hereinafter, an example of an adjustment procedure using the optical axis adjustment device 21 will be described. 1. Determine the lighting method. 2. The optical system is changed to be optimal for the determined illumination method. Selection of optical elements (6a-6f). Setting the magnification of the imaging system 101 (determination of the zoom position of the lens system 9). Aperture 11
Selection (selection of opening shape and size). Change the position of the mercury lamp 1 in the optical axis direction. etc 3. Remove the reticle 15 from the stage 16 and
An illumination state on the image plane of the projection optical system 17 is checked by a measuring device (not shown) on the surface 20. 4. The rotation angles of the wedge glasses 21a and 21b are calculated from the result of the procedure 3, and the wedge glasses 21a and 21b are respectively rotated to designated positions by a driving device (not shown).

The above measurement may be performed on the object surface where the pattern surface of the reticle 15 is located.

In the above adjustment procedure, the illuminance distribution is measured each time the illumination method is switched, and the rotation angles of the wedge glasses 21a and 21b are calculated based on the measurement results.
The rotation angles of a and 21b may be obtained and stored in a memory, and the wedge glasses 21a and 21b may be automatically rotated by a predetermined angle when the illumination method is switched.

The wedge glass 21 is provided for each lighting method.
Instead of having the designated rotation angles of a and 21b, the rotation angles at which the projection accuracy is improved on average in all the illumination methods to be used may be obtained, and the wedge glasses 21a and 21b may be fixed to those angles.

In this embodiment, the optical axis adjusting device 21 is made of two wedge glasses having the same angle.
It may be composed of three or more wedge glasses. In this case, the wedge angle of the wedge glass having the largest wedge angle needs to be equal to or less than the sum of the wedge angles of the other two or more wedge glasses.

In this embodiment, the optical axis adjusting device 21 is arranged closer to the light source than the optical elements 6a to 6f. However, the optical axis adjusting device 21 is arranged closer to the optical integrator 10 than the optical elements 6a to 6f. You may. The point is that the optical integrator 10 may be disposed at a place where the incident position can be changed without changing the incident angle on the light incident surface 10a so much.

In each of the above embodiments, when the illumination method is changed, the wedge glass is used to adjust the illuminance unevenness on the surface to be illuminated to a minimum, but this is not always the case.
For example, the rotation angle of the wedge may be automatically adjusted when the projection accuracy is deteriorated due to a temporal change of the optical system (a change in the characteristics of the coating of the lens or the mirror or a change in the luminance distribution of the lamp arc). Good.

In each of the above embodiments, the optical elements 6a to 6f
Is described as six types, but is not limited to this number. The present invention can be applied even when there is no optical element.

Next, an embodiment of a device manufacturing method using the projection exposure apparatus shown in FIGS. 1 to 3 will be described.

FIG. 6 shows a manufacturing flow of a device (a semiconductor chip such as an IC or an LSI, a magnetic head, a liquid crystal panel, or a CCD). In step 1 (circuit design), the circuit of the semiconductor device is designed. In step 2 (mask fabrication), a mask (reticle 15) on which the designed circuit pattern is formed
To produce On the other hand, in step 3 (wafer manufacturing), a wafer (wafer 18) is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the prepared mask and wafer. The next step 5 (assembly) is called post-processing,
This is a step of forming chips using the wafer created in step 4, and includes steps such as an assembly step (dicing and bonding) and a packaging step (chip enclosing). In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device created in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7). FIG. 8 shows a detailed flow of the wafer process. Step 11 (oxidation) oxidizes the surface of the wafer (wafer 18). Step 12 (CVD) forms an insulating film on the surface of the wafer. In step 13 (electrode formation), the wafer
An electrode is formed thereon by vapor deposition. Step 14 (ion implantation) implants ions into the wafer. In step 15 (resist processing), a resist (sensitive material) is applied to the wafer. Step 16 (exposure) uses the projection exposure apparatus to expose the wafer from the circuit pattern image of the mask (reticle 15). Step 17 (development) develops the exposed wafer. In step 18 (etching), portions other than the developed resist are removed. In step 19 (resist stripping), unnecessary resist after etching is removed. By repeating these steps, a circuit pattern is formed on the wafer.

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

[0047]

When the present invention is applied to a projection projection exposure apparatus for manufacturing a semiconductor device, an electronic circuit pattern on a reticle surface can be projected on a wafer surface with high accuracy.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of a lighting device of the present invention.

FIG. 2 is a diagram illustrating an example of an optical element of the illumination device in FIG. 1;

FIG. 3 is an explanatory diagram of the optical axis adjusting device of FIG. 1;

FIG. 4 is a diagram showing a conventional lighting device.

FIG. 5 is an explanatory diagram showing how to switch the lighting method in the lighting device of FIG. 4;

FIG. 6 is a diagram showing a flow of a device manufacturing method.

FIG. 7 is a view showing a wafer process of FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mercury lamp 2 Elliptical mirror 3 Cold mirror 5, 9 Lens system 6a-6f Optical element 7 Optical element holding member (turret plate) 10 Optical integrator 11 Aperture member 15 Reticle 17 Projection lens 18 Wafer 21a 21b Wedge glass 22 Parallel plane plate 23a to 23f Wedge glass

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03F 7/20 521 H01L 21/30 515D G02B 7/18 A

Claims (16)

[Claims] 1. An optical system for causing a light beam from a light source to enter an optical integrator and a lighting device for illuminating a surface to be illuminated with multiple light beams formed by the optical integrator, wherein the optical integrator and the first light deflecting member include the optical Are located on the optical axis of the system,
The first transparent wedge and the second transparent wedge serving as the first light deflecting member have substantially the same wedge angle and are individually rotatable around the optical axis. An illumination device, wherein the position of incidence of a light beam from the light source on the optical integrator is changed by rotation of a second wedge. 2. The lighting device according to claim 1, wherein the first light polarizing member deflects a light beam incident on the first light polarizing member in a desired direction at a desired angle. 3. The optical system has an irradiation optical system between the optical integrator and the first light deflecting member, and the light deflecting member is arranged at a front focal position of the irradiation optical system. The lighting device according to claim 1, wherein: 4. The optical system has an irradiation optical system between the optical integrator and the first light deflecting member, and the optical integrator is disposed at a rear focal position of the irradiation optical system. The lighting device according to claim 1, wherein: 5. The device according to claim 1, wherein the first light deflecting member includes two transparent wedges.
The lighting device according to any one of the preceding claims. 6. The apparatus according to claim 1, wherein the first light deflecting member includes three transparent wedges.
The lighting device according to any one of the preceding claims. 7. The lighting device according to claim 6, wherein the wedge angle of the wedge having the largest wedge angle of the three transparent wedges is smaller than the sum of the wedge angles of the other two wedges. 8. A second method of dividing a light beam from the light source into a plurality of light beams and deflecting the plurality of light beams in different directions to cause the plurality of light beams to enter different positions of the optical integrator. The lighting device according to any one of claims 1 to 7, wherein a light deflecting member is provided near the first light deflecting member. 9. A second light deflecting member having a conical deflecting surface for converting a light beam from the light source into a ring-shaped light beam and irradiating the light to the optical integrator with the first light deflecting member.
The lighting device according to any one of claims 1 to 7, wherein the lighting device is provided near the light deflecting member. 10. The illumination device according to claim 8, wherein the second light deflection member is provided between the first light deflection member and the irradiation optical system. 11. The illumination device according to claim 1, wherein the reticle and the wafer are illuminated by the multi-beam. 12. The lighting device according to claim 1, wherein the optical system includes an elliptical mirror. 13. The lighting device according to claim 1, wherein the light source includes a mercury lamp. 14. The lighting device according to claim 1, wherein the wedge has at least one surface inclined with respect to an optical axis of the irradiation optical system. 15. An exposure apparatus, wherein a mask is illuminated by the illuminating device according to claim 1, and a pattern of the illuminated mask is projected on a wafer by a projection optical system. 16. A device manufacturing method, comprising: exposing a wafer with a device pattern using the exposure apparatus according to claim 15; and developing the exposed wafer.