JP2003149740A - Light-projection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-projection device which can perform fine, wide-area light-projection. SOLUTION: The light-projection device, which is provided with a spatial optical modulator constituted including a plurality of mirrors whose reflecting surface tilts can independently be controlled and irradiates the spatial optical modulators with the light from a light source to project the light reflected by the spatial optical modulators on an object is equipped with a 1st optical means which is provided with the plurality of the spatial optical modulators mutually at intervals and receives the incident light reflected by the plurality of spatial optical modulators and projects it as parallel light and a 2nd optical means which erases the light images of gaps between adjacent spatial optical modulators by refracting the parallel light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical projection device using a spatial light modulator.

[0002]

2. Description of the Related Art As a projection exposure apparatus for lithography (one of optical projection apparatuses), there are a mask aligner and a stepper (reduction projection exposure apparatus). The former is an apparatus for collectively exposing a wide area reticle mask pattern. Also,
The latter stepper is dedicated to a semiconductor process, and is an apparatus that exposes a reticle mask pattern by reducing and forming an image for each device size.

However, if the former mask aligner is to be used for device research and development, the reticle becomes very expensive and the delivery time of the reticle becomes very long.
On the other hand, the latter stepper also has the same problem as described above in manufacturing the reticle.

Therefore, recently, a DMD (digital mirror device: one of spatial light modulators) including a plurality of mirrors capable of independently controlling the tilt of a reflecting surface is provided.
A projection exposure apparatus has emerged which controls the rotation of each micromirror by the action of an electrostatic field by a control computer, causes the DMD to carry a predetermined pattern by this rotation control, and projects the predetermined pattern onto an exposure target.

[0005]

However, this D
A projection exposure apparatus using an MD has a difficulty in forming a wide area optical image. That is, while the size of the DMD itself has an upper limit in terms of cost, the size of the micromirror has a lower limit in terms of physical size. However, there is a problem that a fine optical image cannot be formed when the formation is attempted.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a light projection apparatus capable of fine light projection in a wide area.

[0007]

The optical projection apparatus of the present invention comprises:
Provided is a spatial light modulator including a plurality of mirrors capable of independently controlling the inclination of the reflecting surface, irradiating the spatial light modulator with light from a light source, and targeting the light reflected by the spatial light modulator. In a light projection device for projecting onto an object, a plurality of each of the spatial light modulators are provided with a gap between each other, and the plurality of spatial light modulators are provided between the plurality of spatial light modulators and the object. And a second optical means for refracting the parallel light and erasing an optical image in a space between adjacent spatial light modulators. And with.

Here, the "spatial light modulator" is preferably constructed so as to be controllable by a computer. Further, as the "first optical means", for example, an image forming telecentric optical system can be used. Furthermore, as the "second optical means", for example, an optical plate for optical axis offset can be used. When using the "optical axis offset optical plate", a plate having a thickness corresponding to the space between the spatial light modulators is used and installed at an angle at which the optical image in the space between the adjacent spatial light modulators is erased. Needs to be done.

According to this optical projection device, the pattern carried by the plurality of spatial light modulators can be irradiated onto the object at once without gaps (that is, since irradiation of a wide area can be carried out), so that the throughput can be improved. . This light projection apparatus is particularly effective when used for projection exposure when forming a circuit pattern on a semiconductor substrate.

Another optical projection apparatus of the present invention is provided with a spatial light modulator including a plurality of mirrors capable of independently controlling the inclination of a reflecting surface, and the spatial light modulator is irradiated with light from a light source. In the light projection device that projects the light reflected by the spatial light modulator onto an object, a plurality of the light sources and the spatial light modulators are provided in association with each other, and each spatial light modulator is provided separately. A third configuration in which the light reflected from the plurality of spatial light modulators is incident between the plurality of spatial light modulators and the object and is emitted as parallel light Optical means is provided, and the light reflected by the plurality of spatial light modulators is collected and made incident on the third means so that the optical image in the gap between the adjacent spatial light modulators is erased. Is.

Here, the "spatial light modulator" is preferably constructed so as to be controllable by a computer. Further, as the "third optical means", for example, an image forming telecentric optical system can be used.

According to this optical projection device, the patterns carried by the plurality of spatial light modulators can be irradiated onto the object at once without gaps (that is, since irradiation of a wide area can be carried out), so that the throughput can be improved. . This light projection apparatus is particularly effective when used for projection exposure when forming a circuit pattern on a semiconductor substrate.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 shows an optical projection apparatus according to the first embodiment. The light projection device 100 of the first embodiment is configured as follows.

In the figure, reference numeral 1 indicates a light source.
The light source 1 is not particularly limited, but a metal halide lamp, a halogen lamp, a xenon lamp, or the like is used. A reflector 2 is installed near the light source 1.
The reflector 2 reflects the light from the light source 1 into focused light, and four DMDs 3a to 3d in the next stage (refer to the circles in the drawing, reference numeral 3 is used to collectively refer to "DMD").
Acts to turn to. In addition, here, four DMDs 3a to 3d are illuminated by one light source 1, but a plurality of, for example, a set of light sources and reflectors may be provided corresponding to each DMD. Further, parallel light may be used instead of the focused light.

The four DMDs (digital mirror devices) 3a to 3d are arranged in a matrix of 2 rows and 2 columns. The parallel light from the reflector 2 obliquely enters the DMDs 3a to 3d. Each DMD has a square or rectangular shape as a whole, and has a structure in which micromirrors are arranged in a matrix. The rotation of each micro mirror is controlled by the action of an electrostatic field by a control computer (not shown).
It can carry a pattern. In carrying the pattern, the four DMDs 3a to 3d may carry the same pattern or may carry different patterns. The former case is advantageous when a plurality of identical patterns are formed on an object. For example, it is advantageous when the same circuit pattern is formed for each chip on the semiconductor substrate. On the other hand, the latter case is advantageous when different patterns are formed at different locations on the object. For example, it is advantageous when a small amount of other types of circuit patterns are simultaneously formed on a semiconductor substrate. Further, depending on the case, it is possible to form a circuit pattern of one chip by combining different patterns. In the case of the optical projection device 100 of the embodiment, a predetermined gap is provided between the vertical and horizontal DMDs.
This gap is a gap that is inevitably generated due to the structure of the frame of the DMD or the installation of the DMD, but the gap interval can be intentionally adjusted in some cases.

In the figure, reference numeral 4 represents a unity magnification image forming telecentric optical system. This equal-magnification imaging telecentric optical system 4 has an optical axis parallel to the normal direction of the DMDs 3a to 3d. This equal-magnification imaging telecentric optical system 4
Are parallelized light beams (reflected light beams) reflected by the DMDs 3a to 3d and two sets of optical plates for optical axis offset 5 and 6 in the next stage.
It acts to output to. The equal-magnification telecentric optical system 4 includes a plurality of lenses, but is shown here as a single lens for convenience.

Each set of optical plates for optical axis offset 5,
Reference numeral 6 indicates two optical plates for optical axis offset 5a and 5b
And 6a, 6b.

One set of optical axis offset optical plates 5 receives the light from the equal-magnification image forming telecentric optical system 4 first, and two optical axis offsets arranged vertically in FIG. The optical plates 5a and 5b are arranged in a bent state so as to be convex toward the equal-magnification imaging telecentric optical system 4 side. The direction of incidence of light on the optical axis offset optical plate 5 of this one set is parallel to the optical axis of the equal-magnification telecentric optical system 4, and the optical axis offset optical plate 5 of this one set Since the bent portion is located (corresponding to the gap between the upper and lower DMDs) on the same figure, the refraction of light by these two optical axis offset optical plates 5a and 5b causes
The optical image corresponding to the gap between the upper and lower DMDs (in the figure) is erased. It should be noted that the light emitted from the optical plate 5 for optical axis offset of this one set is parallel light, although the vertical width is narrower in the figure than the light emitted from the equal-magnification imaging telecentric optical system 4. Then, the light enters the other set of optical plates 6 for optical axis offset.

The other optical axis offset optical plate 6 receives the light that has passed through the other optical axis offset optical plate 5, and is arranged in front and rear of the drawing in FIG. Optical axis offset optical plates 6a, 6b
Are arranged in a bent state so as to be convex toward the equal-magnification imaging telecentric optical system 4 (see the view from above in FIG. 1). The incident direction of the light on the optical axis 6 is parallel to the optical axis of the equal-magnification telecentric optical system 4, and the bent portion of the optical axis offsetting optical plate 6 of the other set is just (on the same figure) the paper surface. Since the positions are corresponding to the gaps between the front and rear DMDs, the refraction of light by these two optical axis offset optical plates 6a and 6b causes the gaps between the front and rear DMDs (in the same figure). The corresponding optical image is erased, and the light emitted from the optical plate offset optical plate 6 of the other set is the optical axis offset optical plate 5.
Compared with the light emitted from the same, the width in the front and back of the drawing is narrower in the figure, but it becomes parallel light and is incident on the total reflection mirror 7 in the next stage.

The total reflection mirror 7 serves to bend the optical path downward in the figure. Although this total reflection mirror 7 is not always necessary, it is suitable for making the device compact and improving the operability of the device. The light reflected by the total reflection mirror 7 is incident on the equal-magnification imaging telecentric relay optical system 8.

Same-magnification imaging telecentric relay optical system 8
Is composed of a plurality of lenses, but is shown here as a single lens for convenience. The light from the equal-magnification imaging telecentric relay optical system 8 enters the infinity-corrected objective lens optical system 9 in the next stage. Although this equal-magnification imaging telecentric relay optical system 8 is not always necessary, it is suitable when the distance from the total reflection mirror 7 to the object (for example, the object to be exposed) is large or changes greatly.

The infinity correction objective lens optical system 9 is used in a microscope or the like, and has a function of correcting various aberrations. The infinity-corrected objective lens optical system 9 is configured to include an objective lens and an auxiliary lens for image formation. Light emitted from the infinity-corrected objective lens 9 is directed to an object (for example, an exposure object) 10. It is irradiated (projected).

The object 10 is installed on a stage (not shown), and this stage allows the object 10 to move in a direction parallel to the optical axis of the infinity-corrected objective lens 9 and in a plane orthogonal to the optical axis.

According to the optical projection device having such a configuration, the light reflected by the patterns carried by the DMDs 3a to 3d arranged in 2 rows and 2 columns in the vertical and horizontal directions is irradiated by the light source 1 to form a telecentric optical image of equal magnification. The light enters the optical plates 5 and 6 for optical axis offset through the system 4. Then, the optical image for the optical axis offset optical plates 5, 6 erases the optical image in the gap between the vertical and horizontal DMDs. by this,
The patterns carried by the DMDs 3a to 3d arranged vertically and horizontally in 2 rows and 2 columns are substantially connected. Then, the light reflecting the connected pattern is projected onto the object 10 through the total reflection mirror 7, the same-magnification imaging telecentric relay optical system 8, and the infinity correction objective lens optical system 9.

Incidentally, in the figure, the light image at the first image position is in a state where the patterns are separated from each other as in the DMD pattern, and the light image at the second image position is in a state where the patterns are in contact with each other (see FIG. 1). In the circle).

[Second Embodiment] FIG. 2 shows an optical projection apparatus according to the second embodiment. The light projection device 200 of the second embodiment is configured as follows.

The light projection apparatus 200 according to the second embodiment is
The configurations of the total reflection mirror 7, the equal-magnification imaging telecentric relay optical system 8 and the infinity correction objective lens optical system 9 are the same as those of the optical forming apparatus 100 of the first embodiment. Therefore, detailed description thereof will be omitted, and hereinafter, different points will be mainly described.

In the optical projection device 200 of the second embodiment, DM
Four light sources 21 are provided corresponding to D3a to 3d. The light source 21 is not particularly limited, but a metal halide lamp, a halogen lamp, or a xenon lamp is used as in the light projection device 100 of the first embodiment.

The reflector 2 corresponding to each light source 21
Two are provided. The reflector 22 reflects the light from the light source 21 into parallel light, and the four DMDs 3a in the next stage.
It acts to turn to 3d.

The four DMDs (digital mirror devices) 3a to 3d are installed in a matrix of 2 rows and 2 columns, and the D and D are more vertical and horizontal than in the case of the optical projection device 100 of the first embodiment.
The gap between the MDs is large (see the circle in the figure).
The parallel light from the reflector 22 obliquely enters the DMDs 3a to 3d. In this case, the parallel light from the reflector 22 is reflected by the corresponding DMD and is set so as to go to the diaphragm position of the next-stage equal-magnification imaging telecentric optical system 4, and the lights from the four DMDs 3a to 3d are equal-magnified. DMDs 3 gathered in front of the image telecentric optical system 4
The light in the state in which the patterns are substantially connected is made incident on the equal-magnification imaging telecentric optical system 4.
Then, when the light is emitted from the equal-magnification imaging telecentric optical system 4, the optical image in the gap between the DMDs is erased.

Each DMD has a square or rectangular shape as a whole, and has a structure in which micromirrors are arranged in a matrix. Each micromirror is rotated by an electrostatic field action by a control computer (not shown). It is controlled so that a predetermined pattern can be carried by this rotation control.
The point that d may carry the same pattern or different patterns may be the same as in the case of the optical projection device 100 of the first embodiment.

In the optical projection device 200 of the second embodiment, the optical axis offsetting optical plates 5 and 6 are not provided between the equal-magnification imaging telecentric optical system 4 and the total reflection mirror 7.

According to the optical projection device 200 thus constructed, the patterns carried by the DMDs 3a to 3d arranged vertically and horizontally in two rows and two columns are illuminated by the light source 21 and are transmitted to the unity-magnification imaging telecentric optical system 4. It is incident. In this case, light in a state in which the patterns carried by the DMDs 3a to 3d arranged vertically and horizontally in two rows and two columns are connected to each other enters the equal-magnification imaging telecentric optical system 4. In other words, vertical and horizontal D
The light from which the optical image in the gap between the MDs is erased is incident on the equal-magnification imaging telecentric optical system 4. As a result, the light emitted from the equal-magnification imaging telecentric optical system 4 is projected onto the object 10 via the total reflection mirror 7, the equal-magnification imaging telecentric relay optical system 8, and the infinity correction objective lens optical system 9. It

Incidentally, in the figure, the light images at the first image position and the second image position are in a state where the patterns are in contact with each other (see the circle in FIG. 2).

[Third Embodiment] FIG. 3 shows an optical projection apparatus according to a third embodiment. The light projection device 300 of the third embodiment is configured as follows.

This optical projection device 300 is different from the optical projection device 200 of the second embodiment in that each DMD 3 and its D
The point is that two double-sided telecentric lenses 31 and 32 are provided separately from the equal-magnification imaging telecentric optical system 4 corresponding to MD3. Since the other points are the same as those of the light projection device 200 of the second embodiment, the same reference numerals as in the case of the second embodiment are given and the description thereof is omitted.

The light projection apparatus 300 is not particularly limited, but the DMD 3 and the equal-magnification imaging telecentric optical system 4 are included.
Used when the distance between and must be large.

Subsequently, D in the optical projection device 300
Regarding the mutual MD positioning method, DMD3a and DMD
3B will be described with reference to FIG. 4, alignment is performed so that one line at the right end of the DMD 3a and one line at the left end of the DMD 3b overlap. Specifically, a half mirror 50 having a small reflectance is provided at the intermediate image and each DMD
Only the lines that should overlap are made bright. In this case, D
When the MD is properly tiled (superposed), the light from the right end line of the DMD 3a is reflected by the half mirror 50 and transferred to the left end line of 3b, while D
The light from the left end line of the MD 3b is reflected by the half mirror 50 and transferred to the right end line of 3a. And DM
The retroreflection from D is highest at this time. This means that the DMDs are positioned relative to each other by finding the highest position.

[Fourth Embodiment] FIG. 5 shows an optical projection apparatus according to a fourth embodiment. The light projection device 400 of the fourth embodiment is configured as follows.

This optical projection device 400 is different from the optical projection device 200 of the second embodiment in that the lights reflected by the four DMDs 3 are made incident on different equal-magnification image forming telecentric optical systems 44, respectively. The point is that the light emitted from the image forming telecentric optical system 44 is reflected by the total reflection mirror 45, and then is made to enter the unity-magnification image forming telecentric relay optical system 46 in the combined state. In addition,
The configurations of the total reflection mirror 7, the equal-magnification imaging telecentric relay optical system 8 and the infinity correction objective lens optical system 9 are the same as those of the optical forming apparatus 100 of the first embodiment. Therefore, the same reference numerals as in the case of the second embodiment are attached and the description thereof is omitted.

In this light projection device 400, the light emitted from the equal-magnification image forming telecentric relay optical system 46 is the one in which the light image in the gap between the vertical and horizontal DMDs 3 is erased.
The optical image of each DMD 3 will be inclined. However, when the reduction ratio is large, the influence of the inclination is small, so that it is sufficiently practical.

Although the embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to such embodiments and various modifications can be made without departing from the scope of the invention.

For example, the optical projection device 10 of the above embodiment.
In the case of 0,200, the image is projected onto the object 10 via the infinite correction objective lens optical system 9, but a finite correction objective lens system may be installed instead of the infinite correction objective lens optical system 9.

In the present invention, the light from the light source is transmitted to the DMD.
In the above, the case of irradiating the object with this reflected light was described. It is also possible to irradiate the object, for example, after it has entered the component, for example, the optical plate for optical axis offset.

[0045]

The effects of the typical ones of the present invention will be described. A spatial light modulator including a plurality of mirrors capable of independently controlling the inclination of a reflecting surface is provided, and the spatial light modulator is provided with a light source. In the light projection device for irradiating light from, and projecting the light reflected by the spatial light modulator onto an object,
A plurality of each of the spatial light modulators are provided with a gap between each other, between the plurality of spatial light modulators and the object,
A first optical unit that receives the light reflected by the plurality of spatial light modulators and emits the parallel light as parallel light, and an optical image of a gap between the adjacent spatial light modulators that refracts the parallel light is formed. Since the second optical device for erasing is provided, the throughput of forming a fine and wide area optical image is improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a main part of an optical projection device according to a first embodiment.

FIG. 2 is a configuration diagram of a main part of an optical projection device according to a second embodiment.

FIG. 3 is a configuration diagram of a main part of an optical projection device according to a third embodiment.

FIG. 4 is a diagram for explaining a DMD positioning method.

FIG. 5 is a configuration diagram of a main part of an optical projection device according to a fourth embodiment.

[Explanation of symbols]

1, 21 Light source 2, 22 Reflector 3 DMD 4, 44 1x imaging telecentric optical system 5, 6 Optical axis offset optical plate 7 Total reflection mirror 8 1x imaging telecentric relay optical system 9 Infinity correction objective lens optical system 10 objects

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazumi Haga             37-share, 33-53, 3-chome, Kakusen, Komae-shi, Tokyo             Ceremony company New Creation

Claims (5)

[Claims] 1. A spatial light modulator including a plurality of mirrors capable of independently controlling the tilt of a reflecting surface is provided, and the spatial light modulator is irradiated with light from a light source. In a light projection device that projects reflected light onto an object, a plurality of each of the spatial light modulators are provided with a gap between each other, and the plurality of spatial light modulators are provided between the object and the spatial light modulator. First optical means for entering the light reflected by the spatial light modulator and emitting it as parallel light, and refracting the parallel light to erase the optical image in the gap between the adjacent spatial light modulators. An optical projection device comprising: a second optical unit. 2. The optical projection device according to claim 1, wherein the first optical means is a 1 × imaging telecentric optical system. 3. The optical projection device according to claim 1, wherein the second optical means is an optical plate for optical axis offset. 4. A spatial light modulator including a plurality of mirrors capable of independently controlling the inclination of a reflecting surface is provided, and the spatial light modulator is irradiated with light from a light source. In a light projection device for projecting reflected light onto an object, a plurality of the light sources and the spatial light modulators are provided in association with each other, and each spatial light modulator is configured to irradiate from a different angle. The third optical means for emitting the light reflected by the plurality of spatial light modulators and emitting the light as parallel light is provided between the plurality of spatial light modulators and the object, and the third optical means is adjacent to each other. An optical projection apparatus, characterized in that light reflected by the plurality of spatial light modulators is collected and made incident on the third means so that an optical image in a gap of the spatial light modulator is erased. 5. The optical projection apparatus according to claim 4, wherein the third optical means is a 1 × imaging telecentric optical system.