JP2007042858A - Projection aligner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection aligner having a simple constitution which exactly aligns a substrate under projection to form a pattern on the substrate. <P>SOLUTION: The projection aligner has an alignment light radiating means for radiating an alignment light on a projection lens, from the back side of an exposure light irradiating means to a mounting means for irradiating a first reference mark provided on the mounting means and a second reference mark provided on a pattern substrate with the alignment light. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a projection exposure apparatus for irradiating a pattern substrate on which a pattern to be projected is formed with exposure light and projecting the pattern onto a projection target substrate for exposure. In particular, the present invention relates to a projection exposure apparatus that irradiates alignment light used when positioning a projection substrate or the like from a position opposite to the exposure light irradiation unit with respect to a mounting unit on which the projection substrate is placed.

  A projection exposure apparatus is an apparatus for irradiating exposure light, projecting a pattern formed on a pattern substrate onto a projection substrate, and forming a pattern on the projection substrate in order to manufacture a printed wiring board or a semiconductor device. is there. When a pattern is projected onto a projection substrate, it is necessary to accurately project the pattern formed on the pattern substrate to a desired position on the projection substrate, and the pattern substrate and the projection substrate must be accurately aligned in advance. I must.

Position alignment between the pattern substrate and the projection substrate is performed using a reference position mark. For example, in addition to the pattern, a reference position mark is previously formed on the pattern substrate, a reference position mark is also formed on the projection substrate, and these reference position marks are overlapped with each other before the pattern is projected onto the projection substrate. The position of the substrate to be projected is adjusted. The position of the projection substrate is adjusted while observing the reference position mark using an optical measuring means such as a microscope (for example, see Patent Document 1).
Japanese Patent No. 2658051

  However, in the conventional projection exposure apparatus described above, alignment light is emitted from a light source provided above the pattern substrate, and both the reference position mark of the pattern substrate and the reference position mark of the projection substrate are passed through the projection lens. I was observing. The projection lens is used to change the pattern image of the pattern substrate to be projected onto the projection substrate to a desired size, and is adjusted to match the wavelength of exposure light such as ultraviolet rays.

  Alignment is not performed by directly observing the reference position mark of the pattern substrate and the reference position mark of the projection substrate, but the image of the reference position mark of the pattern substrate and the image of the reference position mark of the projection substrate. This was done by observing two images. For this reason, the optical system becomes complicated and accurate alignment may be difficult.

  Further, as described above, the projection lens is adjusted to match the wavelength of exposure light such as ultraviolet rays. On the other hand, when observing the reference position mark, visible light such as white light is used as alignment light. For this reason, when the reference position mark is observed through the projection lens with the visible light that is the alignment light emitted from the light source above the pattern substrate, the wavelength of the alignment light is different from the wavelength of the exposure light. In some cases, the position of the image of the reference position mark to be deviated. Furthermore, when an optical element such as a beam splitter is used, the contrast of the image that can be detected with a microscope is significantly reduced. Therefore, a deflection plate and a wavelength plate are used to prevent the contrast from decreasing, and more complicated optical systems are used. I had to be.

  The present invention has been made in view of the above-described points, and an object of the present invention is to accurately align the pattern substrate and the projection substrate with a simple configuration and a simple procedure. To provide a projection exposure apparatus.

  In order to achieve the above object, a projection exposure apparatus according to the present invention is an alignment light irradiation unit that emits alignment light toward the projection lens from the opposite side of the exposure light irradiation unit with respect to the mounting unit. Alignment light irradiation means for irradiating alignment light to the first reference mark provided on the placing means and the second reference mark provided on the pattern substrate, and when the alignment light is applied to the first reference mark The first reference mark image position obtained via the projection lens and the first fiducial mark image position obtained when the second fiducial mark is irradiated with the alignment light are first detected. When the placing means is adjusted by the position adjusting means to a position where the detection means, the position of the image of the first reference mark and the position of the image of the second reference mark satisfy a predetermined relationship, the alignment light is first Detecting the position of the image of the first reference mark obtained by irradiating the quasi-mark and the position of the image of the third reference mark obtained by irradiating the third reference mark provided on the projection substrate with the alignment light Second detecting means.

Specifically, the projection exposure apparatus according to the present invention includes:
Exposure light irradiation means for irradiating exposure light onto a pattern substrate on which a pattern to be projected is formed, and projecting the pattern onto a projection substrate;
A projection lens that forms an image of the pattern on the projection substrate when the exposure light is irradiated onto the pattern substrate;
Position adjusting means for adjusting the position of the mounting means on which the projection substrate is mounted;
A projection exposure apparatus comprising:
Alignment light irradiation means for emitting alignment light toward the projection lens from a side opposite to the exposure light irradiation means with respect to the placement means, wherein the first reference mark provided on the placement means, and Alignment light irradiation means for irradiating the alignment light to a second reference mark provided on the pattern substrate;
When alignment light is irradiated onto the first reference mark, the position of the image of the first reference mark obtained through the projection lens, and when the alignment light is irradiated onto the second reference mark First detection means for detecting the position of the image of the second reference mark obtained;
When the positioning means is adjusted by the position adjusting means to a position where the position of the image of the first reference mark and the position of the image of the second reference mark satisfy a predetermined relationship, the alignment light is emitted from the first reference mark. The position of the image of the first reference mark obtained by irradiating the reference mark, and the position of the image of the third reference mark obtained by irradiating the third reference mark provided on the projection substrate with the alignment light. And a second detection means for detecting
including.

  According to the above-described invention, the alignment light is emitted from the position opposite to the exposure light irradiating unit with respect to the placing unit, to the first reference mark provided on the placing unit, and provided on the pattern substrate. Since the alignment light irradiation means for irradiating the second reference mark is provided, the optical path length of the alignment light from the alignment light irradiation means to the first detection means can be shortened. For this reason, adjustment of an optical path can be performed easily. In addition, the first reference mark and the second reference mark can be observed with fewer various optical elements. For this reason, the position of each reference mark can be accurately detected while reducing the influence of the optical element. Further, in the conventional apparatus, the alignment light is emitted from the alignment light irradiation unit toward the projection lens through the pattern substrate from the same side as the exposure light irradiation unit. The alignment light is irradiated from the alignment light irradiation means toward the projection lens from the side opposite to the exposure light irradiation means, so that the alignment light is transmitted to the first reference mark and the pattern substrate without passing through other optical elements. It is possible to irradiate the second fiducial mark provided on the first reference mark, and the efficiency of reaching the alignment light detecting means can be improved.

  Further, when the alignment light is irradiated on the first reference mark, the position of the image of the first reference mark obtained through the projection lens and when the alignment light is irradiated on the second reference mark are obtained. Since the first detection means for detecting the position of the image of the second reference mark to be detected is provided, the efficiency of reaching the detection means for the alignment light is improved, so the image of the first reference mark detected by the first detection means And the image of the second reference mark can be clarified. As a result, when alignment is performed by image processing or the like based on the detection result of the first detection means, accurate alignment can be performed with high accuracy. Furthermore, the alignment can be easily adjusted.

Further, when the positioning means is adjusted by the position adjusting means so that the position of the image of the first reference mark and the position of the image of the second reference mark satisfies a predetermined relationship, the alignment light is applied to the first reference mark. A second position for detecting the position of the image of the first reference mark obtained by irradiation and the position of the image of the third reference mark obtained by irradiating the third reference mark provided on the projection substrate with the alignment light. It was set as the structure which has a detection means. Thus, after positioning the pattern substrate and the placement means using the first detection means, the respective positions of the first reference mark and the third reference mark are stored, so that It is possible to align with the substrate to be projected. In order to store these positions, it is preferable to connect an imaging device such as a CCD camera connected to the image processing apparatus to the first detection means and the second detection means. As a result, an image photographed by a CCD camera or the like is converted into data, image processing is performed using the converted image data, and the position of each reference mark can be calculated and stored in the storage memory.
Note that “the position where the image of the first reference mark and the image of the second reference mark satisfy a predetermined relationship” means that the images of the first reference mark and the second reference mark that can be detected by the first detection unit overlap each other. In addition to a position satisfying the relationship, a position where the distance between these images has a predetermined distance is also included.

  In addition, since the second detection means detects the images of the first reference mark and the third reference mark without using a projection lens or the like, the optical path length of the alignment light can be shortened, and accurate and accurate alignment is achieved. Not only can be performed, but also the alignment can be easily adjusted.

  As described above, since the projection exposure apparatus according to the present invention includes the alignment light irradiation unit, the first detection unit, and the second detection unit described above, the alignment light can be efficiently detected by each detection unit. The structure of the entire exposure apparatus can be simplified.

  In the projection exposure apparatus according to the present invention, it is preferable that the wavelength of the alignment light is the same as the wavelength of the exposure light.

According to the above-described invention, since the wavelength of the alignment light is the same as the wavelength of the exposure light, after aligning with the alignment light having the same wavelength as the exposure light, the exposure light is irradiated at the same position. Thus, the pattern on the pattern substrate can be projected and exposed on the projection substrate, and accurate and accurate alignment can be achieved.
Here, the wavelength of the alignment light and the exposure light being “same” is not limited to the case where both wavelengths are the same value, but in the alignment of the pattern substrate, the mounting means, and the projection substrate, Depending on the characteristics, the case where aberrations caused by alignment light having different wavelengths is within an allowable range is included. Generally, when the wavelength of the exposure light is 0.365 μm, the wavelength is the same when the wavelength of the alignment light is in the range of 0.365 μm ± 0.1 μm, preferably 0.365 μm ± 0.05 μm.

  Further, as the projection exposure apparatus according to the present invention, the wavelength of the alignment light is different from the wavelength of the exposure light, and the position adjusting means generates on-axis chromatic aberration and lateral chromatic aberration for the alignment light different from the wavelength of the exposure light in the projection lens. It is also preferable to adjust the mounting means to a position for correcting the above.

According to the above-described invention, the alignment can be performed by the alignment light different from the wavelength of the exposure light. In particular, since the substrate to be projected is not exposed by irradiation of alignment light different from the wavelength of exposure light, alignment can be performed accurately and accurately.
In the above-described invention, alignment is performed using alignment light different from the wavelength of exposure light. Therefore, the wavelength of this alignment light is measured in advance, and axial chromatic aberration and lateral chromatic aberration caused by the wavelength difference are calculated and calculated. By adjusting the position of the mounting means based on the result, it is possible to perform accurate and accurate alignment even when alignment light having a wavelength different from that of the exposure light is used.

  In the projection exposure apparatus according to the present invention, it is preferable that the alignment light satisfies the relation α1> α2 + α3. Here, α1 is the spread angle of the alignment light emitted from the alignment light irradiation means, α2 is the spread angle of the exposure light that is irradiated from the exposure light irradiation means to the pattern substrate and can pass through the projection lens, and α3 is the light of the projection lens. The maximum angle between the principal ray of the exposure light irradiated to the pattern substrate from the exposure light irradiation means at a position away from the axis and the parallel line of the optical axis of the projection lens is shown. The principal ray means a ray that passes through the center of the aperture of the projection lens.

  Even when a telecentric projection lens is used, the angle α3 varies depending on the position of the exposure light irradiation means away from the optical axis of the projection lens. However, according to the above-described invention, by using the alignment light that satisfies the above relational expression, the alignment light irradiated from the alignment light irradiation unit is irradiated onto the mounting unit, and the first detection unit passes through the projection lens. It becomes possible to detect. Therefore, brighter alignment light can be detected by the first detection means, and accurate alignment can be performed with high accuracy.

Furthermore, it is desirable that the projection exposure apparatus according to the present invention has a measuring unit capable of measuring a relative position between the third reference mark of the projection target substrate and the first reference mark of the mounting unit.
According to the above-mentioned invention, since the relative position between the third reference mark of the substrate to be projected and the first reference mark of the mounting means is provided, it is possible to measure the relative position directly or indirectly. The first reference mark can be aligned based on the measurement result without using a light microscope or the like and finely adjusting the position of the third reference mark. As a result, it is possible to automate the positioning of the mounting means by the position adjusting means.

Furthermore, in the projection exposure apparatus according to the present invention, it is desirable that the first detection means and the second detection means are optical microscopes.
According to the above-described invention, it is visually recognized that the positions of the detection images as detection results are in a position where they overlap each other, or the distance calculated from the position of the detection image satisfies a predetermined distance. It becomes possible to do.

Furthermore, in the projection exposure apparatus according to the present invention, it is desirable that the third reference mark is made of a material having a small coefficient of thermal expansion.
According to the above-described invention, the third fiducial mark is made of a material having a small coefficient of thermal expansion, so that the influence of temperature when irradiating the pattern can be reduced and accurate positioning can be performed. An appropriate pattern can be formed on the projection substrate.

  According to the above-described invention, the alignment light is emitted from the opposite side of the exposure light irradiation means to the projection lens toward the projection lens, and the first reference mark provided on the placement means and the pattern substrate are provided. Since the second reference mark and the alignment light irradiation means for irradiating the alignment light are provided, the optical path length of the alignment light can be shortened, and various optical elements can be reduced. Therefore, the efficiency of reaching the alignment light detection means is improved, and accurate and accurate positioning can be easily performed. Furthermore, the structure of the entire projection exposure apparatus can be simplified.

<<<< first embodiment >>>>
<< Configuration >>
FIG. 1 is a perspective view showing a projection exposure apparatus 100 according to the first embodiment of the present invention. The projection exposure apparatus 100 includes an exposure light source 110 that irradiates exposure light, a pattern substrate 120 (hereinafter referred to as a reticle plate), a reticle support base 130, a projection lens 140, a work support base 150, and a projection target. The optical system includes a substrate 160 and a light source 170 that emits alignment light, and a measurement system that includes a reticle microscope 180a (180b) and a work microscope 190a (190b). Although FIG. 1 shows a case where the projection substrate 160 is placed on the work support base 150, when aligning the reticle plate 120 and the work support base 150, the work support base 150 includes This is performed without placing the projection substrate 160.

<Optical system>
[Light source 110 for exposure light]
On the upper part of the projection exposure apparatus 100, an exposure light source 100 is provided by being supported by a support member (not shown). The light source 110 for exposure light is installed on the support member so as to emit exposure light of a predetermined wavelength, for example, ultraviolet rays in the + Z direction shown in FIG.

[Reticle plate 120]
A reticle plate 120 is provided in the traveling direction of the exposure light emitted from the exposure light source 110. The reticle board is a photomask used for forming a conductor pattern on the projection substrate 100 described later when a printed wiring board or a semiconductor device wafer is manufactured. Here, a conductor pattern means the figure formed with a conductive material with a printed wiring board.

  FIG. 2 is a plan view showing the outline of the reticle plate 120. The reticle plate 120 is provided with a pattern forming portion 122 made of a glass substrate at substantially the center, and a pattern 126 is provided on the glass substrate. The pattern 126 is made of a material that can block exposure light irradiated from the light source 110, for example, chromium, and has the same shape as the pattern to be formed on the projection substrate 160. In a region where the pattern 126 is not formed, the glass substrate is in a transparent state, and exposure light emitted from the exposure light source 110 and alignment light emitted from an alignment light source 170 described later are transmitted. it can.

  The peripheral region that circulates around the pattern forming unit 122 is also formed of a material that blocks exposure light. Two reference mark forming portions 124a and 124b are formed in the circumference region, and plus-shaped reference marks 128a and 128b for indicating the reference position of the pattern 126 are formed in each reference mark forming portion. . The reference marks 128a and 128b are made of a material that reflects alignment light so as to be detected as an image by a reticle microscope 180a and 180b, which will be described later, and the reference mark forming portions 124a and 124b other than the reference marks 128a and 128b The glass substrate is in a transparent state, and the alignment light emitted from the alignment light source 170 can be transmitted.

  In the reticle plate 120 shown in FIG. 1, the pattern forming portion 122 and the two reference mark forming portions 124a and 124b are shown in order to show the pattern forming portion 122 and the two reference mark forming portions 124a and 124b. The pattern forming portion 122 and the two reference mark forming portions 124a and 124b are positioned directly above the reticle support base 130, which will be described later, so that the reticle is formed on the upper surface of the reticle plate 120. It is formed on the lower surface of the plate 120.

[Reticle support stand 130]
On reticle support base 130, reticle plate 120 is detachably mounted. A through hole (not shown) is formed at a position of the reticle plate 120 where the pattern forming portion 122 and the two reference mark forming portions 124a and 124b are located. The exposure light emitted from the light source 110 described above can pass through the pattern forming unit 122 and enter the projection lens 140 through this through hole. Further, alignment light, which will be described later, can also pass through the projection lens 140 and enter the reference mark forming portions 124a and 124b of the reticle plate 120 through the through hole.

[Projection lens 140]
A projection lens 140 is provided below the reticle support 130 described above. The projection lens 140 changes the size of the image of the pattern 126 formed on the reticle plate 120 by the projection lens 140 and projects the image of the pattern 126 onto the projection substrate 160 to form a conductor pattern having a desired size. it can.

  Although not shown in FIG. 1, as shown in FIG. 11, which will be described later, there is a stop 144 inside the projection lens, which can be converted so that the cross-sectional size of the luminous flux of incident light becomes a desired size. Here, a light beam emitted from the light source away from the optical axis 142 of the projection lens 140 to the projection lens 140 and passing through the center of the stop 144 to the image plane is referred to as a principal ray 146. The angular deviation (parallelism) of the principal ray 146 with respect to the optical axis 142 at each point in the irradiation area by the ray is called the telecentricity. The projection lens when the telecentricity is 0 degree is referred to as “telecentric lens”, and the other cases are referred to as “non-telecentric lenses”, which are distinguished from each other. Therefore, when the projection lens 140 is a telecentric lens, the optical axis 142 and the principal ray 146 are parallel.

[Work support 150]
The work support 150 is provided below the projection lens 140. The work support base 150 can move in the X direction, the Y direction, the Z direction, and the θ direction, and is connected to a motor (not shown) for driving in each direction. A control device (not shown) is connected to these motors, and the control device issues a drive signal for moving the work support 150 to a predetermined position. Two reference mark forming portions 152 a and 152 b described later are formed on the end side of the work support base 150.

[Projected substrate 160]
The projection substrate 160 is a substrate on which a conductor pattern is formed, is made of a glass epoxy substrate or the like, and is detachably mounted on the work support base 150. On the projection substrate 160, a pattern formation portion 162 is formed at a substantially central portion, and two reference mark formation portions 164a and 164b, which will be described later, are formed on the end sides of the projection substrate 160.

  FIG. 3 is a plan view showing a state in which the projection substrate 160 is placed on the workpiece support 150. When the exposure light is irradiated from the light source 110 and the pattern 126 is formed on the projection substrate 160, the projection substrate 160 is placed on the work support 150. Further, when aligning the reticle plate 120 and the work support table 150 by irradiating the work support table 150 with alignment light from an alignment light source 170 to be described later, the projection substrate 160 is mounted on the work support table 150. Do not place.

  Two reference mark forming portions 152a and 152b are formed in the vicinity of one end side of the work support base 150, and each reference mark formation portion indicates a reference position for aligning the work support base. Plus-shaped reference marks 154a and 154b are formed. The reference marks 154a and 154b are made of a material that reflects alignment light so that they can be detected as an image, and the reference mark forming portions 152a and 152b other than the reference marks 154a and 154b are made transparent on the glass substrate. The alignment light emitted from the light source 170 can be transmitted.

  In addition, two reference mark forming portions 164a and 164b are formed in the vicinity of one edge of the projection substrate 160, and the alignment of the projection substrate 160 and the work support 150 is set in each reference mark formation portion. Plus-shaped reference marks 166a and 166b are formed to indicate a reference position for performing. The reference marks 166a and 166b can be detected as images.

  Furthermore, after aligning the projection substrate 160, when the exposure light irradiated from the light source 110 is irradiated onto the projection substrate 160 via the reticle plate 120 and the projection lens 140, the reticle plate 120 is exposed. The formed pattern 126 is projected onto the projection substrate 160. In the pattern forming portion 162, the portion that is shaded by the pattern 126 formed on the reticle plate 120 is not exposed, and the portion that is not shaded by the pattern is exposed.

[Light source 170 for alignment light]
The alignment light source 170 is a light source that emits alignment light that is used to align the reticle plate 120 and the projection substrate 160 by adjusting the position of the work support 150. The alignment light source 170 is located below the workpiece support 50. In order to shorten the optical path length of the alignment light, reduce various optical elements, and improve the efficiency of reaching the alignment light detection means, a projection lens is provided from the side opposite to the exposure light source 110 with respect to the work support base 150. It is preferable to irradiate the alignment light from the alignment light source 170 directly to the reference mark forming part 152a (152b) of the workpiece support base 150 without going through other optical elements.

  The alignment light source 170 includes an LED light source 172, a condenser lens 174, and a ground glass 176 in order to uniformly irradiate the alignment light (FIG. 4A). The alignment light emitted from the LED light source 172 is condensed by the condenser lens 174 and then passes through the ground glass 176, so that the reference mark forming part 152a (152b) of the work support 150 is uniformly irradiated with the alignment light. I do.

  In addition, there is also a rod lens 178 instead of the ground glass 176 (FIG. 4B). The alignment light emitted from the LED light source 172 is condensed by the condensing lens 174, and then passes through the rod lens 178 to become highly uniform alignment light. The reference mark forming portion 152a ( 152b) is uniformly irradiated with alignment light.

<Detection system>
[Reticle microscopes 180a and 180b]
Reticle microscopes 180a and 180b are provided in the vicinity of reticle support 130, and mirrors 182a and 182b are provided in front of each of two reticle microscopes 180a and 180b. These reticle microscopes 180a and 180b and mirrors 182a and 182b are fixed to the same reticle microscope support (not shown). This reticle microscope support is configured to reciprocate in the X direction as indicated by the arrows in the figure. When the reticle microscope support is moved, the reticle microscopes 180a and 180b and the mirrors 182a and 182b move together while maintaining the relative positional relationship between the reticle microscopes 180a and 180b and the mirrors 182a and 182b. be able to.

  When the reticle microscope support is moved in the negative X direction, the reticle 182a is positioned above the reference mark forming portion 124a, and the reticle 182b is positioned above the reference mark forming portion 124b. A microscope support can be positioned. Hereinafter, this position is referred to as a forward position of the reticle microscope support base.

  In addition, when the reticle microscope support base is moved in the positive direction of the X direction, the reticle microscope support base is positioned so that the mirror 182a and the mirror 182b are positioned at a position separated from the reticle support base 130 in the X direction. Can do. Hereinafter, this position is referred to as a retracted position of the reticle microscope support base.

[Work microscope 190a and 190b]
Two workpiece microscopes 190a and 190b are provided in the vicinity of the workpiece support 150 described above, and mirrors 192a and 192b are provided in front of each of the two workpiece microscopes 190a and 190b. These workpiece microscopes 190a and 190b and mirrors 192a and 192b are fixed to the same workpiece microscope support (not shown). The work microscope support base can be reciprocated in the X direction as indicated by arrows in the figure. When the work microscope support base moves, the work microscopes 190a and 190b and the mirrors 192a and 192b move together while maintaining the relative positional relationship between the work microscopes 190a and 190b and the mirrors 192a and 192b. be able to.

  When the work microscope support base is moved in the positive direction of the X direction, the workpiece 192a is positioned above the reference mark forming portion 152a and the mirror 192b is positioned above the reference mark forming portion 152b. A microscope support can be positioned. Hereinafter, this position is referred to as a forward position of the work microscope support base.

  Further, when the work microscope support base is moved in the negative direction of the X direction, the work microscope support base is positioned so that the mirror 192a and the mirror 192b are located at a position separated from the work support base 150 in the X direction. Can do. Hereinafter, this position is referred to as a retracted position of the work microscope support base.

  Note that the advance position of the reticle microscope support base and the advance position of the work microscope support base are aligned in advance. Thus, by storing each position, it is possible to align the reticle plate 120, the work support 150, and the projection substrate 160 on the work support 150.

  In order to store each position, it is preferable to connect an image sensor such as a CCD camera connected to an image processing apparatus to the reticle microscope 180a (180b) and the work microscope 190a (190b). An image captured by a CCD camera or the like is converted into data, image processing is performed using the converted image data, the position of each reference mark can be calculated, and stored in a storage memory. Therefore, the position of the image of each reference mark is detected from the images of the reference marks 128a and 128b on the reticle plate 120, the reference marks 154a and 154b on the work support 150, and the reference marks 166a and 166b on the projection substrate 160. can do.

<< Positioning and exposure procedure >>
A procedure for performing alignment and exposure using the projection exposure apparatus 100 according to the first embodiment will be described below with reference to FIGS. FIG. 5 is a view showing the projection exposure apparatus 100 that aligns the reticle plate 120 and the work support 150, and FIG. 6 shows an image picked up by the image pickup device connected to the reticle microscopes 180a and 180b. FIG. FIG. 7 is a diagram showing the projection exposure apparatus 100 that aligns the workpiece support 150 and the projection substrate 160. FIG. 8 is an image picked up by an image sensor connected to the workpiece microscopes 190a and 190b. It is a figure which shows an image. The pattern forming portion 122 formed on the reticle plate 120 and the two reference marks 128a and 128b are shown as broken rectangles. In the present embodiment, alignment is performed using alignment light having the same wavelength as predetermined exposure light.

<First step>
First, as shown in FIG. 5, after the reticle plate 120 is placed on the reticle support base 150, the reticle microscope support base is moved to the forward position.

  Then, alignment light is irradiated from the alignment light source 170 positioned below the workpiece support 150 to the reference mark forming portions 152 a and 152 b of the workpiece support 150. A part of the alignment light is reflected by the reference marks 154a and 154b formed on the reference mark forming portions 152a and 152b, and the other alignment light passes through the reference mark forming portions 152a and 152b. The transmitted alignment light enters the reticle microscopes 180a and 180b via the projection lens 140, the reference mark forming portions 124a and 124b of the reticle plate 120, and the mirrors 182a and 182b. The image of the reference marks 124a and 124b of the reticle plate 120 and the image of the reference marks 154a and 154b of the workpiece support 150 are detected by the image pickup elements of the reticle microscopes 180a and 180b, and the captured images are stored as image data ( FIG. 6 (a)). In addition, the left figure of Fig.6 (a) is what was imaged with the reticle microscope 180a, the right figure is what was imaged with the reticle microscope 180b, and below-mentioned FIG.6 (b) is also the same.

<Second step>
Next, the work support base 150 is moved by the control device, and the position is adjusted so that the images of the reference marks 154a and 154b of the work support base 150 overlap the images of the reference marks 124a and 124b of the reticle plate 120 (FIG. 6 (b)).

  In the first embodiment, the workpiece support 150 is moved by the control device and aligned. However, instead of the workpiece support 150, the reticle support 130 is provided with a control device. It is also possible to perform. In this case, a motor (not shown) that can move in the X direction, the Y direction, the Z direction, and the θ direction and is driven in each direction is connected to the reticle support base 130, and a control device that connects to these motors. Is provided.

<Third step>
Next, after aligning the reticle plate 120 and the work support 150, in order to align the work support 150 and the projection substrate 160 placed on the work support 150, FIG. ), Move the reticle microscope support to the retracted position and move the work microscope support to the advanced position.

  Then, alignment light is irradiated to the reference mark forming portions 152 a and 152 b of the work support table 150 from the alignment light source 170 provided below the work support table 150. A part of the alignment light is reflected by the reference marks 154a and 154b formed in the reference mark forming portions 152a and 152b. Other alignment light passes through the reference mark forming portions 152a and 152b. The transmitted alignment light enters the work microscopes 190a and 190b via the mirrors 192a and 192b. The workpiece microscopes 190a and 190b detect images of the reference marks 154a and 154b on the workpiece support 150, and store the captured images as image data (FIG. 8A). The left figure in FIG. 8A is taken with the work microscope 190a, the right figure is taken with the work microscope 190b, and the same applies to FIGS. 8B and 8C described later. is there.

<4th step>
Next, as shown in FIG. 7B, after placing the projection substrate 160 on the workpiece support 150, images of the reference marks 166a and 166b formed on the projection substrate 160 are obtained by the workpiece microscopes 190a and 190b. It detects (FIG.8 (b)). The images of the reference marks 154a and 154b of the work support table 150 stored in step 3 are indicated by dotted lines.
Then, the work support 150 is moved to a position where the images of the reference marks 166a and 166b formed on the projection target substrate 160 overlap with the stored images of the reference marks 154a and 154b of the work support 150. FIG. 8 (c)). The workpiece support 150 is moved by controlling a motor in the X, Y, Z, or θ direction that drives the workpiece support 150.

<Step 5>
After performing alignment using alignment light emitted from the alignment light source 170 provided below the work support table 150 in steps 1 to 4, exposure light is emitted from the exposure light source 110, By irradiating the projection substrate 160 mounted on the work support 150 with exposure light via the reticle plate 120 and the projection lens 140, the pattern 126 formed on the reticle plate 120 is changed to the projection substrate 160. Projected on.

<< Outline of First Embodiment >>
The advance position of the reticle microscope support base and the advance position of the work microscope support base are aligned in advance. Therefore, the images of the reference marks 154a and 154b provided on the work support 150 are aligned with the images of the reference marks 128a and 128b on the reticle plate 120, and the aligned reference marks 154a and 154b are used. And stored as the reference positions of the reference marks 166a and 166b provided on the projection substrate 160.

  As a result, the positions of the reference marks 166a and 166b on the projection substrate 160 placed on the workpiece support 150 can be aligned with the positions of the reference marks 128a and 128b on the reticle plate 120. The alignment with the reticle plate 120 can be performed.

  Accordingly, since the alignment light is emitted from the position opposite to the exposure light source 110 to the work support base 150 by the configuration and procedure shown in the first embodiment, the light source 170 to the reticle microscopes 180a and 180b. The optical path length can be shortened. For this reason, adjustment of an optical path can be performed easily. Further, the position of each reference mark can be accurately detected while reducing the influence of the optical element. Furthermore, the alignment light is irradiated to the reference marks 128a and 128b of the reticle plate 120 and the reference marks 154a and 154b of the work support base 150 without using any other optical element, so that the alignment light is emitted from the reticle. The efficiency of reaching the microscopes 180a and 180b is improved. Therefore, it is possible to accurately detect the position of each reference mark without being affected by other optical elements, and it is possible to easily perform accurate and accurate alignment.

  Furthermore, since it is not necessary to use an optical element such as a beam splitter, the contrast of an image that can be detected by a microscope is not significantly reduced, so that a deflecting plate and a wavelength plate for preventing a reduction in contrast are not required. In addition, the structure of the entire projection exposure apparatus can be simplified.

  The reference marks 128a and 128b, 154a and 154b, and 166a and 166b described above are preferably made of a material having a small coefficient of thermal expansion. By selecting such a material, the influence of temperature at the time of pattern irradiation can be reduced, and an appropriate pattern can be formed on the projection substrate 160.

<<< Second Embodiment >>>
In the above-described first embodiment, alignment is performed so that the respective reference marks are superimposed, but an image sensor such as a CCD camera connected to an image processing apparatus is used as the reticle microscope 180a (180b) and the workpiece. By connecting to the microscope 190a (190b), an image photographed by a CCD camera or the like is converted into data, image processing is performed using the converted image data, the position of each reference mark is calculated, and stored in a storage memory can do. Therefore, it is possible to perform alignment based on the stored position using an interferometer or the like.

  FIG. 9 is a diagram showing a projection exposure apparatus 200 according to the second embodiment of the present invention. The configuration of the projection exposure apparatus 200 according to the second embodiment different from the projection exposure apparatus 100 according to the first embodiment is that an interferometer 210 is provided. In FIG. 9, the same reference numerals are given to components common to the projection exposure apparatus 100 according to the other first embodiment.

  In the projection exposure apparatus 200 according to the second embodiment, after aligning the reticle plate 120 and the workpiece support 150, the reference marks 154a and 154a of the workpiece support 150 detected and stored by the microscopes 190a and 190b are stored. Rather than aligning the reference marks 166a and 166b of the projection substrate 160 with respect to the position of the image 154b, alignment is performed using an interferometer.

  Specifically, after aligning the reticle plate 120 and the work support base 150, a predetermined position of the work support base 150 and a predetermined position of the projection substrate 160 are measured by an interferometer, and the work support base is measured. The relative position A of the reference marks 166a and 166b of the projection substrate 160 with respect to the 150 reference marks 154a and 154b is measured by the interferometer 210, and alignment is performed based on the measurement result.

  Accordingly, when alignment is performed using the projection exposure apparatus 200 according to the second embodiment, the relative position A of the reference mark 166a (166b) of the substrate 160 to be projected with respect to the reference mark 154a (154b) of the workpiece support 150 is set. By automating the alignment based on the above, fine alignment using an optical microscope or the like is not required, and accurate and accurate alignment can be performed easily.

<<< Third Embodiment >>>
In FIG. 5, the alignment light irradiated from the alignment light source 170 to the reference mark forming portions 152a and 152b of the work support 150 is not refracted, and the projection lens 140 and the reference mark forming portion 124a of the reticle plate 120 are not refracted. , 124b and mirrors 182a and 182b, and enters the reticle microscopes 180a and 180b. Here, FIG. 10 shows that the alignment light emitted from the light source 170 is refracted by the reference mark forming portions 152a and 152b of the work support 150, and then enters the projection lens 140 and is detected by the reticle microscopes 180a and 180b. It is the figure which showed the optical path of the alignment light to.

  As shown in FIG. 10, even in the case of refraction, by using a telecentric projection lens, the projection exposure apparatus 300 of the present invention can be applied to perform accurate and accurate alignment easily and quickly. .

  Further, the alignment light has a spread angle as shown in FIG. When the relational expression α1> α2 + α3 is satisfied with respect to the spread angle (α1) of the alignment light emitted from the alignment light source 170, brighter alignment light can be detected by the reticle microscope 180a (180b). Alignment can be performed accurately.

  Here, α1 is the spread angle of the alignment light emitted from the alignment light source 170, α2 is the spread angle of the exposure light that is emitted from the exposure light source 110 and can pass through the stop 144 in the projection lens 140, and α3 is This represents the maximum angle between the principal ray 146 of the exposure light irradiated from the exposure light source 110 away from the optical axis 142 of the projection lens 140 and the parallel line of the optical axis of the projection lens 140.

  Even when a telecentric projection lens is used, the angle α3 varies depending on the position of the exposure light source 110 away from the optical axis 142 of the projection lens 140. However, by using alignment light that satisfies the above relational expression, the alignment light irradiated from the alignment light source 170 is applied to the reference mark portion 162a (162b) of the work support base 150, and the diaphragm 144 of the projection lens 140 is moved. It can be detected by the reticle microscope 180a (180b). Therefore, since brighter alignment light can be detected by the reticle microscope 180a (180b), accurate alignment can be performed with high accuracy.

<<< Fourth embodiment >>>>
In the above-described embodiment, the alignment light having the same wavelength as the exposure light is used. However, the alignment can be performed using the alignment light having a wavelength different from that of the exposure light. FIG. 12 is a diagram showing a projection exposure apparatus 400 when alignment light having a wavelength different from that of exposure light is used. In FIG. 12, the same code | symbol was attached | subjected to the component which is common in the projection exposure apparatus 100 by 1st Embodiment.

  When alignment light having a wavelength different from that of the exposure light is used, lateral chromatic aberration and axial chromatic aberration due to a wavelength difference between the exposure light and the alignment light are generated. Here, in FIG. 12, B indicates a positional shift in the X and Y directions due to lateral chromatic aberration due to different wavelengths, and C indicates a positional shift in the Z direction due to axial chromatic aberration due to different wavelengths. D shows the image of the reference mark 154a (154b) when the alignment light having the same wavelength as the exposure light is irradiated on the reference mark 154a (154b) of the work support 150 and imaged by the reticle microscope 180a (180b). The position of the work support 150 to be focused by the microscope 180a (180b) is irradiated to the reference mark 154a (154b) of the work support 150 by the alignment light different from the wavelength of the exposure light, and the reticle microscope 180a (180b). Indicates the position of the work support 150 where the image of the reference mark 154a (154b) is in focus by the reticle microscope 180a (180b).

  Therefore, before irradiating the alignment light and performing alignment, the wavelength of the alignment light is measured, the lateral chromatic aberration and the axial chromatic aberration caused by the wavelength difference are calculated, and the position of the mounting means is adjusted based on the calculation result. Thus, accurate alignment can be performed even when alignment light having a wavelength different from that of exposure light is used.

  Further, since the projection substrate is not exposed to the irradiation of the alignment light different from the wavelength of the exposure light, the alignment can be performed accurately and accurately.

  As described above, according to the embodiment of the present invention, the alignment light is irradiated from the position opposite to the exposure light source 110 to the work support base 150. Therefore, the reticle microscope 180a and The optical path length to 180b can be shortened. For this reason, adjustment of an optical path can be performed easily. In addition, it is possible to observe the reference marks 128a (128b) on the reticle plate 120 and the reference marks 154a (154b) on the work support base 150 by reducing the number of various optical elements, and the alignment light is transmitted to the reticle microscope 180a and The efficiency of reaching 180b is improved. As described above, accurate and accurate alignment can be easily performed. Furthermore, the structure of the entire projection exposure apparatus can be simplified.

1 is a perspective view showing a projection exposure apparatus 100 according to a first embodiment of the present invention. 2 is a plan view showing an outline of a reticle plate 120. FIG. FIG. 6 is a plan view showing a state where a projection substrate 160 is placed on a work support base 150. It is a figure which shows the light source 170 of alignment light. 2 is a diagram showing a projection exposure apparatus 100 that aligns a reticle plate 120 and a work support 150. FIG. It is a figure which shows the image imaged with the image pick-up element connected to the two reticle microscopes 180a and 180b. FIG. 2 is a diagram showing a projection exposure apparatus 100 that aligns a workpiece support 150 and a projection substrate 160. FIG. 2 is a diagram showing a projection exposure apparatus 100 that aligns a workpiece support 150 and a projection substrate 160. It is a figure which shows the image imaged with the image pick-up element connected to two work microscopes 190a and 190b. It is the figure which showed the projection exposure apparatus 200 by the 2nd Embodiment of this invention. FIG. 6 is a diagram showing an optical path of alignment light when alignment light is refracted at reference mark forming portions 152a and 152b of a work support base 150. It is a side view which shows the outline of the projection exposure apparatus 300 for demonstrating the relational expression regarding the alignment light which has a divergence angle. It is the figure which showed the projection exposure apparatus 400 at the time of using the alignment light of a different wavelength from exposure light.

Explanation of symbols

100, 200, 300, 400 Projection exposure apparatus 110 Light source for exposure light 120 Reticle plate (pattern substrate)
128a, 128b Reticle plate 120 reference mark (second reference mark)
130 Reticle support stand 140 Projection lens 142 Optical axis 144 Aperture 150 Work support stand (mounting means)
154a, 154b Reference mark (first reference mark) of work support base 150
160 Projected substrate (projected substrate)
166 Reference mark (third reference mark) of projection substrate 160
170 Light source for alignment light 180a, 180b Reticle microscope (first detection means)
190a, 190b Work microscope (second detection means)
A Relative position of the reference mark 166a (166b) of the projection substrate 160 with respect to the reference mark 154a (154b) of the workpiece support table 150 B Position shift due to lateral chromatic aberration due to different wavelengths C Position shift due to axial chromatic aberration due to different wavelengths D Exposure light The position of the work support that focuses on the wavelength of the light E The position of the work support that focuses on the light of a wavelength different from the wavelength of the exposure light

Claims (7)

Exposure light irradiation means for irradiating exposure light onto a pattern substrate on which a pattern to be projected is formed, and projecting the pattern onto a projection substrate;
A projection lens that forms an image of the pattern on the projection substrate when the exposure light is irradiated onto the pattern substrate;
Position adjusting means for adjusting the position of the mounting means on which the projection substrate is mounted;
A projection exposure apparatus comprising:
Alignment light irradiation means for emitting alignment light toward the projection lens from a side opposite to the exposure light irradiation means with respect to the placement means, wherein the first reference mark provided on the placement means, and Alignment light irradiation means for irradiating the alignment light to a second reference mark provided on the pattern substrate;
When alignment light is irradiated onto the first reference mark, the position of the image of the first reference mark obtained through the projection lens, and when the alignment light is irradiated onto the second reference mark First detection means for detecting the position of the image of the second reference mark obtained;
When the positioning means is adjusted by the position adjusting means to a position where the position of the image of the first reference mark and the position of the image of the second reference mark satisfy a predetermined relationship, the alignment light is emitted from the first reference mark. The position of the image of the first reference mark obtained by irradiating the reference mark, and the position of the image of the third reference mark obtained by irradiating the third reference mark provided on the projection substrate with the alignment light. And a second detection means for detecting
A projection exposure apparatus comprising: The wavelength of the alignment light is the same as the wavelength of the exposure light;
The projection exposure apparatus according to claim 1. The wavelength of the alignment light is different from the wavelength of the exposure light,
The position adjusting means adjusts the placing means to a position for correcting axial chromatic aberration and lateral chromatic aberration generated with respect to the alignment light different from the wavelength of the exposure light in the projection lens;
The projection exposure apparatus according to claim 1. The alignment light is
α1> α2 + α3
α1: A spread angle of alignment light emitted from the alignment light irradiation means α2: A spread angle of exposure light that can be irradiated from the exposure light irradiation means to the pattern substrate and pass through the projection lens α3: A position away from the optical axis of the projection lens Satisfy the maximum angle between the principal ray of exposure light irradiated to the pattern substrate from the exposure light irradiation means and the parallel line of the optical axis of the projection lens,
4. A projection exposure apparatus according to claim 2, wherein Measuring means capable of measuring a relative position between the third reference mark of the projection substrate and the first reference mark of the placing means;
5. The projection exposure apparatus according to claim 1, wherein the projection exposure apparatus is a projection exposure apparatus. The first detection means and the second detection means are optical microscopes;
6. The projection exposure apparatus according to claim 1, wherein The third reference mark is made of a material having a small coefficient of thermal expansion.
7. The projection exposure apparatus according to claim 1, wherein

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