JP2000091216A - Aligner, adjustment method, and method of exposure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique capable of positioning parts put near to an X-ray generating part by using a low-cost apparatus with respect to an aligner with an X-ray exposure light beam. SOLUTION: In a aligner, an X-ray light source 3 for generating an X-ray beam by making a material in a plasma state is provided. The X-ray beam from the X-ray light source 3 is used as an exposure light beam. The aligner includes light-source position observing systems 21X and 21Y for forming an image of the X-ray light source 3 when visual light is cast along with the X-ray beam from the X-ray light source 3. In the aligner in which an X-ray beam from the plasma, especially a laser-plasma X-ray beam, is used as a light source, the position of the part is reproduced with high accuracy even when the parts around the light source is replaced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus, and more particularly to an exposure apparatus using soft X-rays, commonly called EUV (Extreme Ultra Violet) light, as exposure light, an adjustment method of the exposure apparatus, and an exposure method. , X of this exposure apparatus
It relates to a linear light source.

[0002]

2. Description of the Related Art An example of a projection exposure apparatus using soft X-rays as exposure light is shown in FIG. Laser light including light from infrared to visible light emitted from the laser light source 1 is condensed on a condensing position 3 by a laser light condensing optical system 1a. In the vicinity of the light condensing position 3, the tip of the nozzle 2 is open. The gaseous object ejected from the nozzle 2 receives high-intensity laser light at the light condensing position 3, and its center is turned into plasma to emit soft X-rays, which serves as a soft X-ray light source. Therefore, the light condensing position 3 is an emission point of X-rays.

The soft X-ray emitted from the light emitting point 3 is converted into parallel light by the first X-ray focusing optical system 4 and the second X-ray focusing optical system 5 and then focused by the condenser optical system 7. After the optical path is bent by the plane mirror 7a, the reflection type mask 8
Layered on top. The soft X-rays selectively reflected according to the pattern drawn on the reflective mask 8 are guided to the surface 10 to be exposed by the projection optical system 9, and the pattern of the mask 8 is transferred to the surface 10 to be exposed. . Since the transmittance of the soft X-ray to the atmosphere is low, the device in which the soft X-ray is used is covered by the vacuum chamber 11.

[0004]

Now, the actual operation of the above device will be considered. Since the plasma is generated in the vicinity of the nozzle 2, some deterioration is unavoidable. In addition, since the first X-ray condensing optical system 4 is also contaminated by the scattered particles of the nozzle 2 that have been worn, there is a possibility that the reflectance may decrease with use. Therefore, these parts 2 and 4 need to be replaced every certain use time. At the time of replacement, the part to be newly replaced must be accurately returned to the position where the part to be replaced was. Because, in the technical field of projection exposure equipment, precise resolution is required, so even a slight modification of the illumination system,
This is because it affects the image. However, since the field of projection exposure apparatuses that use soft X-rays as exposure light is immature, proposals for a method of positioning at the time of component replacement have been proposed.
It was not done at all. It is desired that the position adjusting means be as inexpensive as possible because the entire apparatus is expensive. Accordingly, an object of the present invention is to provide a technology that enables an inexpensive apparatus to perform positioning of a component arranged near a portion that generates X-rays in an exposure apparatus that uses X-rays as exposure light. And

[0005]

A soft X used as exposure light
Two types of lines are currently being considered. 1
One is radiation emitted by a synchrotron, and the other is plasma X-rays emitted from plasma, particularly laser plasma X-rays emitted from plasma excited by a laser. Of these, the synchrotron radiation light is expensive because its light source becomes expensive and large-scale (extremely large in volume), and it takes out X-rays for a plurality of exposure apparatuses from a single light source. It has been pointed out that when a trouble occurs in the light source, a plurality of devices stop simultaneously. Therefore, plasma X-rays are regarded as a favorite as a light source of this type of exposure apparatus. For this reason, in the present invention, plasma X-rays, particularly laser plasma X-rays, were examined.

[0006] The above-mentioned "positioning a part to be newly replaced to a position where a part to be replaced was" is, in other words, a relative position between an optical system and a light source (light emitting point). Is to maintain the relationship. For that purpose, the light emitting point must be able to be measured. However, an optical device for X-rays tends to be expensive due to a special wavelength, both for the routing system and the light receiving element. Therefore, the present invention focuses on the properties of the light source. That is, a plasma X-ray light source such as a laser plasma X-ray emits visible light from the same location together with the X-rays because the X-ray is generated by concentrating energy at a specific location. Therefore, by specifying the light emitting point of the visible light, it is possible to specify the light emitting point of the X-ray. In order to grasp the relative positional relationship between the light source and the optical system as the object of the present invention, the position of the light source may be observed through the optical system.

The present invention has been made based on the above considerations. That is, the present invention is provided with an X-ray light source for generating X-rays by converting an object into plasma, and exposing the X-rays emitted from the X-ray light source to exposure light. An exposure apparatus comprising: a light source position observation system that forms an image of the X-ray light source using visible light emitted together with the X-rays from the X-ray light source.

The present invention also relates to a method for adjusting an exposure apparatus, comprising an X-ray light source for generating X-rays by converting an object into plasma, and using the X-rays emitted from the X-ray light source as exposure light. An adjustment method characterized in that the X-ray light source is positioned using visible light emitted together with the X-ray from a line light source. Further, the present invention provides an exposure method including an X-ray light source that generates X-rays by converting an object into plasma, and using the X-rays emitted from the X-ray light source as exposure light. An exposure method is characterized in that the exposure is performed after the X-ray light source is positioned using visible light emitted together with the exposure.

[0009]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of a projection exposure apparatus according to the present invention. Laser light including light from infrared to visible light emitted from the laser light source 1 is emitted from the laser light focusing optical system 1a.
As a result, light is condensed on the light condensing position 3. In the vicinity of the light condensing position 3, the tip of the nozzle 2 is open. The gaseous object ejected from the nozzle 2 receives high-intensity laser light at the light condensing position 3, and its center is turned into plasma to emit soft X-rays, which serves as a soft X-ray light source. Therefore, focusing position 3
Is the X-ray emission point.

The soft X-ray emitted from the light emitting point 3 is converted into parallel light by the first X-ray focusing optical system 4 and the second X-ray focusing optical system 5. In this embodiment, an elliptical mirror is used as the first X-ray focusing optical system 4. A parabolic mirror is used as the second X-ray focusing optical system 5, and the parabolic mirror 5 is an off-axis parabolic surface whose rotational symmetry axis does not pass through the center of the reflecting surface. It is a mirror. The light emitting point 3 is located at the first focal point of the elliptical mirror 4 and the focal point of the parabolic mirror 5 is located at the second focal point.

The soft X-rays converted into parallel light by the X-ray focusing optical systems 4 and 5 are thereafter guided to a fly-eye optical system 6. The fly-eye optical system 6 includes a first fly-eye optical system 6.
a and the second fly-eye optical system 6b. Each element mirror of the first fly-eye optical system 6a is constituted by a concave mirror. Thus, soft X-rays incident on the first fly-eye optical system 6a are split into wavefronts by the first fly-eye optical system 6a. A number of secondary light sources are formed near the two fly-eye optical system 6b. That is, the light emitting point 3 and the second fly's eye optical system 6b have a substantially conjugate relationship. In FIG. 1, in order to avoid congestion in the drawing, the parallel light incident on the first fly-eye optical system 6a is depicted as being reflected by the parallel light. However, as described above, the parallel light incident on the first fly-eye optical system 6a is actually collected near the second fly-eye optical system 6b.

Each element mirror of the second fly-eye optical system 6a corresponds to each element mirror of the first fly-eye optical system 6a. Each element mirror of the second fly-eye optical system 6b is also constituted by a concave mirror, and the curvature of the element mirror of the first fly-eye optical system 6a is substantially equal to the curvature of the element mirror of the second fly-eye optical system 6b. . As a result, for each soft X-ray that has been wavefront-divided by the fly-eye optical system 6, the relationship between the incident position and the incident angle on each element mirror of the first fly-eye optical system 6a corresponds to the corresponding second fly-eye. The relationship is converted into a relationship between an emission angle and an emission position from each element mirror of the optical system 6a.

The soft X-rays emitted from the fly-eye optical system 6 at the same exit angle are then condensed by a condenser lens 7, and after the optical path is bent by a plane mirror 7a,
They are superimposed on the reflective mask 8. Since the exit angle from the fly-eye optical system 6 corresponds to the position of incidence on each element mirror of the first fly-eye optical system 6a, the illumination area on the reflective mask 8 and the individual fly-eye optical system 6a The element mirror has a conjugate relationship. Therefore, when the illumination area on the reflective mask 8 is, for example, arc-shaped,
The shape of each element mirror of the first fly-eye optical system 6a also becomes an arc shape.

A pattern is drawn on the reflective mask 8, and soft X-rays selectively reflected according to the pattern in the illumination area are guided to the surface 10 to be exposed by the projection optical system 9,
Thus, the pattern of the mask 8 is transferred to the surface 10 to be exposed. Since the soft X-rays incident on the reflective mask 8 and the soft X-rays reflected from the reflective mask 8 are separated by the plane mirror 7a, the soft X-rays incident on the reflective mask 8 slightly deviate from telecentricity. I have. On the other hand, the exposed surface 10
Is softly almost completely telecentric. Since the transmittance of the soft X-ray to the atmosphere is low, the device in which the soft X-ray is used is covered by the vacuum chamber 11.

Now, the visible light emitted together with the soft X-rays from the light condensing position 3 of the laser light condensing optical system 1a, that is, the light emitting point 3, is converted into parallel light by the X-ray condensing optical systems 4 and 5. To the fly-eye optical system 6. In the present embodiment, the diameter of the light beam of the soft X-ray and the visible light traveling toward the fly-eye optical system 6 is set slightly larger than the entire diameter of the first fly-eye optical system 6a. Therefore, the soft X-rays and the visible light go around the outside of the first fly-eye optical system 6a. Soft X-rays and visible light that have passed outside the first fly-eye optical system 6a are:
After the optical path is bent by the plane mirror 20, the light is condensed by the first light source position observation system 21X and the second light source position observation system 21Y, and an image of the light emitting point 3 is formed on the first screen 22X and the second screen 22Y, respectively. The first screen 22X and the second screen 22Y are connected to the vacuum chamber 1 via a window (not shown) provided on the outer wall of the vacuum chamber.
Observable from outside. In addition, these 1st and 2nd
The screens 22X and 22Y may be provided on the outer wall of the vacuum chamber. However, in this embodiment, the first fly-eye optical system 6
Of the soft X-rays and visible light that have passed outside of “a”, the image of the light emitting point 3 is formed solely by visible light. Therefore, as the light source position observation systems 21X and 21Y, for example, ordinary lenses can be used.

FIG. 2 is a diagram showing an optical path of the light source position observing system when the optical path is not bent by the plane mirror 20, and FIG. 3 is a sectional view of a light beam traveling to the fly-eye optical system in this case. Show. 2 and 3, AX represents the optical axis of the soft X-ray (exposure light) traveling toward the fly-eye optical system, ax represents the optical axis of the first light source position observation system 21X,
ay represents the optical axis of the second light source position observation system 21Y. In FIG. 2, the parabolic mirror 5 deflects the optical path by 90 degrees in the YZ plane (corresponding to the plane of FIG. 1), but the deflection angle is not limited to 90 degrees. These figures 2
3 and FIG. 3, the first light source position observation system 2
The optical axes ax and ay of the 1X and the second light source position observation system 21Y are
The exposure light is arranged to be orthogonal to the optical axis AX of the exposure light. That is, the first and second light source position observation systems 21X, 21X
In Y, the light emitting point 3 of the X-ray light source is set in two different directions (X
Direction and Y direction).

Indices (scales) are printed on the first screen 22X and the second screen 22Y as shown in FIG. Therefore, by observing the image of the light emitting point 3 formed on the screens 22X and 22Y with the naked eye, the three-dimensional position of the light emitting point orthogonal to the optical axis AX of the exposure light can be specified. Here, the light-emitting point 3 in the YZ plane in FIG.
Can be specified, and the position of the light emitting point 3 in the XY plane in FIG. 3 can be specified by the second light source position observation system 21Y. In the present embodiment, the light emitting points 3 are set to 9
Although the observation is performed from a direction different by 0 degrees, it is possible to specify the three-dimensional position of the light emitting point by observing from two different directions. Therefore, the angle formed by the two directions is not limited to 90 degrees. Further, observation may be performed from two or more directions. In addition, since the transmittance of the soft X-rays to the atmosphere is very low, the soft X-rays do not reach the eyes to cause any trouble. However, for further safety, glass that transmits visible light and blocks the soft X-rays is provided. May be provided in the first and second light source position observation systems.

The parts that need to be replaced because they deteriorate with time are mainly the nozzle 2 and the first X-ray focusing optical system 4. The image of the light emitting point 3 obtained through the light source position observation systems 21X and 21Y changes its position regardless of which position is shifted. Therefore, if the position adjustment of the nozzle 2 and the first X-ray condensing optical system 4 is performed so that the position of the image of the light emitting point 3 returns to the original position after the replacement work, the replacement part can be arranged at a desired position. Can be done.

In this embodiment, the screen 2
For example, a two-dimensional photoelectric conversion element such as a CCD may be arranged at the positions 2X and 22Y, and the position of the light emitting point 3 may be detected based on the CCD. Further, a relay optical system for re-imaging the images of the screens 22X and 22Y may be provided, and a two-dimensional photoelectric conversion element such as a CCD may be arranged at an image position by the relay optical system. In this case, the position of the light emitting point 3 is detected not on the basis of the CCD but on the basis of an index on the screens 22X and 22Y. As described above, when the image of the light emitting point 3 is detected by the photoelectric conversion element, the light emitting point 3 can be automatically positioned. At this time, it is preferable to include at least a driving unit that controls the three-dimensional position of the nozzle 2 and a control unit that controls the driving unit based on the output from the photoelectric conversion element.

In the above example, the image of the light emitting point 3 is formed by using the visible light reflected by the first X-ray focusing optical system. A hole may be provided in the elliptical mirror as the system 4, and the light emitting point 3 may be observed from the hole. FIG. 4 shows that the X-ray focusing optical system 4 is provided with two holes 4aX, 4aY, and the holes 4aX, 4a
First and second light source position observation systems 21X and 21Y via Y
Here is an example in which are arranged. At this time, the first light source position observation system 2
In 1X, the position of the light emitting point 3 in a plane orthogonal to the optical axis ax can be observed, and the second light source position observation system 21Y
Then, the position of the light emitting point in a plane orthogonal to the optical axis ay can be observed. In the example of FIG. 4, the optical axes of the first and second light source position observation systems 21X and 21Y are not in a positional relationship of 90 degrees with each other, but they may be arranged so as to be 90 degrees with each other. Also, in the example of FIG. 4, the positions of the screens 22X and 22Y or the screen 2
It is also possible to arrange a CCD at a conjugate position of 2X and 22Y.

Further, the present invention is not limited to the projection exposure apparatus described in the embodiment, but also a method of forming a mask pattern on a photosensitive substrate in a state where a mask as a projection original and a photosensitive substrate as an object to be exposed are separated by a small distance. The present invention can also be applied to a proximity exposure apparatus that transfers data to the upper side. As described above, the present invention is not limited to the above-described embodiment, and can take various configurations without departing from the gist of the present invention.

[0022]

According to the present invention, in an exposure apparatus that uses X-rays emitted from plasma, in particular, laser plasma X-rays as a light source, it is possible to reproduce the positions of the components with high accuracy when exchanging the components around the light source. Moreover, the mechanism added to implement the present invention is extremely inexpensive. In addition, the present invention is not limited to the application at the time of component replacement, and is also applicable to an adjustment for returning a component to a desired position even when a component around the light source is displaced due to aging or the like. it can.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a projection exposure apparatus according to the present invention.

FIG. 2 is an explanatory diagram showing an arrangement of optical axes of a first light source position observation system and a second light source position observation system, and a scale on a first screen and a second screen.

FIG. 3 is a perspective view showing an arrangement of optical axes of a first light source position observation system and a second light source position observation system.

FIG. 4 is a perspective view showing a modification of the light source position observation system.

FIG. 5 is a configuration diagram showing a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Laser light source 1a ... Laser light condensing optical system 2 ... Nozzle 3 ... Condensing position (light emission point) 4 ... X-ray 1st condensing optical system 5 ... X-ray 2nd condensing optical system 6 ... Fly-eye optical system 6a: first fly-eye optical system 6b: second fly-eye optical system 7: condenser lens 7a: plane mirror 8: reflective mask 9: projection optical system 10: exposed surface 11: vacuum chamber 20: plane mirror 21X: first light source Position observation system 21Y Second light source position observation system 22X First screen 22Y Second screen AX Exposure optical axis ax First light source position observation system optical axis ay Second light source position observation system optical axis

Continued on the front page F term (reference) 2H087 KA21 NA04 NA05 TA01 2H097 CA13 CA14 CA15 KA20 5F046 BA02 BA03 CA08 CB03 GA18 GC03

Claims (7)

[Claims] 1. An X-ray light source for generating X-rays by converting an object into plasma, wherein the X-rays emitted from the X-ray light source are provided.
An exposure apparatus that uses a line as exposure light, comprising: a light source position observation system that forms an image of the X-ray light source using visible light emitted from the X-ray light source together with the X-ray. 2. An exposure apparatus according to claim 1, wherein said X-ray light source is a laser plasma X-ray light source for irradiating said object with a laser beam to convert said object into plasma. 3. The light source position observing system includes first and second light source position observing systems, wherein the first and second light source position observing systems observe the X-ray light source from different directions. The exposure apparatus according to claim 1, wherein the exposure apparatus is positioned at a predetermined position. 4. The light source position observing system comprises first and second light source position observing systems, and the optical axes of the first and second light source position observing systems are at least partially at least the optical axis of the X-ray. The exposure apparatus according to any one of claims 1 to 3, wherein the exposure apparatus is arranged so as to be in parallel with each other and at an angle of 90 with each other with respect to the optical axis of the X-ray. 5. The X-ray light source is disposed in a vacuum chamber, and the light source position observation system is configured to observe an image of the X-ray light source by the visible light from outside the vacuum chamber. The exposure apparatus according to claim 1, wherein the exposure apparatus comprises: 6. An X-ray light source for generating X-rays by converting an object into plasma, wherein the X-rays emitted from the X-ray light source are provided.
An adjustment method for an exposure apparatus using a line as exposure light, wherein the X-ray light source is positioned using visible light emitted together with the X-ray from the X-ray light source. 7. An X-ray light source for generating X-rays by converting an object into plasma, wherein the X-rays emitted from the X-ray light source are provided.
An exposure method using a line as exposure light, wherein the exposure is performed after positioning the X-ray light source using visible light emitted together with the X-ray from the X-ray light source.