TW202338925A - Optical device, exposure apparatus and exposure method - Google Patents

Abstract

The present invention can use a simple configuration and suppress the increase of astigmatic difference at the same time to perform adjustment of shift amount in the technique of shifting the light traveling path. The present invention is related to an optical device that shifts the traveling path of an input light to output an output light along the light path parallel to and different from the light path of the input light, and an exposure apparatus and an exposure method using the same. The optical device is equipped with: a first wedge prism that sets the incident angle of the input light to be the angle allowing the deflection angle of the emergent light to be minimum; a second wedge prism that has an apex angle approximately the same as that of the first wedge prism and is reversely arranged opposite to the first wedge prism; a shift amount adjusting mechanism that supports the first wedge prism and the second wedge prism and changes the distance between them to adjust the shift amount; and a correction optical component that is arranged in the light path of the input light or the light path of the output light and corrects the astigmatic difference occurring in the output light.

Description

Optical device, exposure device and exposure method

The present invention relates to an optical device that is applicable to a technology for drawing a pattern on a substrate such as a printed wiring board or a glass substrate and exposing the substrate.

The technology for forming patterns such as wiring patterns on various substrates such as semiconductor substrates, printed wiring substrates, and glass substrates involves a method of injecting a light beam modulated based on drawing data onto a photosensitive layer formed on the surface of the substrate to expose the photosensitive layer. In this technique, in order to draw at an appropriate position while adapting to bending or deformation of the substrate, a means is provided on the optical path to shift the incident position of the light beam relative to the substrate.

For example, in the technology described in Japanese Patent Application Laid-Open No. 2009-244446 (Patent Document 1), a pair of wedge prisms (wedge prisms) arranged opposite to each other in opposite directions are arranged on the optical path. Furthermore, the displacement of the position of the image formed by the light beam on the image plane is achieved by changing the distance between the wedge-shaped lenses. In this technology, the incident angle of light on the pixels is set in such a way that the distance between the pixels is used as a reference value and the astigmatic difference is approximately zero. At this time, there is a problem that the astigmatism difference increases as the distance between the lenses changes. To solve this problem, a solution has been proposed in which the wedge-shaped mirror pair is rotated to change the incident angle of light.

(The problem that the invention wants to solve)

In the above-mentioned prior art, in order to change the displacement without increasing the astigmatism difference, it is necessary to rotate the pair of mirrors according to the change in the distance between the mirrors. In particular, when it is necessary to realize rotational movement at a point, the mechanism for supporting and moving the wedge-shaped pair becomes complicated. In addition, in order to speed up the displacement amount change processing, it is also desired to simplify the mechanism used for support and adjustment. For example, it would be better if the displacement amount could be changed only by changing the distance between the two sides. On these points, the aforementioned prior art still has room for improvement. (Technical means to solve problems)

The present invention was made in view of the above-mentioned problems, and its object is to provide a technology that can adjust the amount of displacement while suppressing an increase in astigmatism difference with a simple structure. .

In one aspect of the present invention, it is an optical device that displaces the traveling path of input light and outputs output light along an optical path that is parallel and different from the optical path of the input light; it has: first The wedge-shaped lens sets the incident angle of the input light to an angle that minimizes the deflection angle of the outgoing light; the second wedge-shaped lens has a vertex angle that is approximately the same as the first wedge-shaped lens and is oppositely the same as the first wedge-shaped lens. The first wedge-shaped ribs are arranged oppositely and emit the output light from the surface opposite to the surface facing the first wedge-shaped ribs; a displacement adjustment mechanism supports the first wedge-shaped ribs and the second wedge-shaped ribs. The mirror changes the distance between them to adjust the displacement; and the correction optical element is arranged in the optical path of the input light or the optical path of the output light to correct the astigmatism difference that occurs in the output light.

In the invention of this constitution, like the technology described in Patent Document 1, the displacement of the optical path is realized by a pair of wedge-shaped lenses formed by combining two wedge-shaped lenses, and by making the gap between the wedge-shaped lenses The displacement is adjusted as the distance changes. However, in the first wedge-shaped lens where the input light is incident, the incident angle in the present invention is not set to minimize the astigmatism difference as described in Patent Document 1, but is set so that the deflection angle becomes the minimum value. At this time, as described in Patent Document 1, the magnitude of the astigmatism difference is substantially constant regardless of the distance between the wedge-shaped lenses. On the other hand, at this time, an astigmatism difference of a size that cannot be ignored remains.

Therefore, in the present invention, a correction optical element for correcting astigmatism is additionally provided on the optical path. Specifically, for example, the astigmatism difference can be corrected by arranging on the optical path an optical element that generates astigmatism to offset the astigmatism (astigmatism) generated by the wedge-shaped lens pair.

If the correction is realized in this way, even if the distance between the wedge-shaped lenses is changed to change the displacement amount, the state after correcting the astigmatic error can be maintained. In other words, it is not necessary to change the correction amount of the astigmatism difference according to the amount of displacement. Therefore, as for the mechanism supporting the pair of wedge-shaped ribs, it is sufficient as long as it can achieve linear motion that changes the distance between the wedge-shaped ribs. Therefore, it can adopt a simpler structure. In addition, since it is not necessary to rotate the wedge-shaped pair in response to changes in the displacement amount, the processing for adjusting the displacement amount can be speeded up.

In addition, in another aspect of the present invention, it is an exposure device, which is provided with: a platform that supports a substrate of a processing object; and an exposure part that modulates a light beam according to predetermined exposure data, and causes the modulated The aforementioned light beam is incident on the surface of the aforementioned substrate through the aforementioned optical device; and a moving mechanism that relatively moves the aforementioned platform and the aforementioned exposure portion.

In the invention of this constitution, when the substrate surface is exposed with the modulated light beam, the aforementioned optical device is provided in the optical path of the light beam. Therefore, when it is necessary to adjust the incident position of the light beam in response to deformation of the substrate or positional shift on the platform, for example, the displacement of light by the optical device can be utilized. The optical device of the present invention has nothing to do with the displacement amount and has small astigmatism, so it is particularly suitable for such applications.

In addition, another aspect of the present invention is an exposure method in which a light beam modulated according to predetermined exposure data is incident on the surface of the substrate to expose the substrate. In the present invention, the optical device having a correction amount adjustment mechanism is disposed on the optical path of the light beam, and the correction amount adjustment mechanism is operated in advance to minimize the astigmatism difference occurring in the output light. optimization. In this way, when the displacement amount adjustment mechanism is operated to change the displacement amount, there is no need to change the correction amount of the correction amount adjustment mechanism.

In the invention of this constitution, by arranging the optical device of the present invention on the optical path, it is possible to adjust the incident position of the light beam with respect to the substrate. Furthermore, if the astigmatism difference is adjusted in advance so that it becomes the minimum (ideally zero), the astigmatism difference will not increase even if the displacement amount is subsequently changed. In addition, the displacement amount can be changed by changing only the distance between the wedges, thereby enabling high-speed adjustment processing. (Compare the effectiveness of previous technologies)

As described above, in the present invention, when light is displaced by two wedge-shaped lenses, the incident angle of light is set under the condition that the deflection angle becomes the minimum, and the residual astigmatism difference is corrected by the correction optical element. Therefore, it is possible to realize an optical device with a relatively simple structure, which can change the displacement amount without increasing the astigmatism difference.

Hereinafter, specific aspects of the optical device of the present invention will be explained by illustrating a plurality of embodiments. Here, an embodiment in which the optical device of the present invention is applied to an exposure device that performs exposure and drawing on a substrate by modulating a light beam will be described. The exposure device draws a pattern on the photosensitive material by irradiating a substrate with a photosensitive material layer such as a resist with a predetermined pattern of laser light. As the substrate to be exposed, for example, various substrates such as printed wiring boards, glass substrates for various display devices, and semiconductor substrates can be appropriately used.

First, two structural examples of an exposure device to which the optical device of the present invention can be applied will be described, and then, a detailed configuration of an optical device applicable to these exposure devices will be described.

<Exposure device of the first structural example> FIG. 1 is a diagram schematically showing a first structural example of an exposure device including the optical device of the present invention. The basic structure of this exposure device 2 is the same as the structure described as "optical device 2" in Patent Document 1. Therefore, descriptions of principles, basic structures, etc. that can be understood by referring to Patent Document 1 will be omitted, symbols will be common as much as possible, and the outline of the device structure will be briefly described here.

For the following explanation, the XYZ orthogonal coordinate system is defined as shown in Figure 1. And let the direction that is horizontal and perpendicular to the paper surface of Figure 1 be the X direction, and let the direction that is orthogonal to it and be horizontal and along the paper surface of Figure 1 be the Y direction. In addition, let the vertical downward direction be the Z direction. That is, FIG. 1 is a side view of the exposure device 2 .

The exposure device 2 includes a movable stage 20 , an exposure head 21 , and a control unit 22 . The movable stage 20 maintains the substrate 9 to be exposed in a horizontal position. The exposure head 21 draws a fine pattern on the substrate 9 by making the modulated light beam incident on the substrate 9 . The control unit 22 controls each part of the device by executing a pre-prepared control program to achieve predetermined actions.

A platform driving mechanism 201 is connected to the movable platform 20 . The stage driving mechanism 201 includes a main scanning driving mechanism that moves the movable stage 20 in the Y direction, a secondary scanning driving mechanism that moves in the X direction, and an elevating mechanism that moves the movable stage 20 in the Z direction. As a driving source of such a mechanism, a linear motor can be used, for example. Thereby, the exposure device 2 can make the exposure beam emitted from the exposure head 21 incident on any position of the substrate 9 to perform drawing.

The exposure head 21 includes a light source 23, an illumination optical system 24, a spatial light modulation element 25, and an imaging optical system 26. The light source 23 is, for example, a lamp that emits light as an exposure beam. The illumination optical system 24 guides the light emitted from the light source 23 toward the spatial light modulation element 25 . The spatial light modulation element 25 modulates the light guided by the illumination optical system 24 according to the predetermined rendering data to generate a modulated light beam.

The illumination optical system 24 includes optical elements such as a reflector 240, a lens 241, an optical filter 242, a rod integrator 243, a lens 244, and reflectors 245 and 246. Through the action of these optical elements, the light from the light source 23 is shaped into a beam and guided toward the spatial light modulation element 25 at a predetermined incident angle.

As the spatial light modulation element 25, for example, a DMD (Digital Micromirror Device), a diffraction grating type spatial light modulation element, etc. can be used. The spatial light modulation element 25 modulates the incident light beam according to the drawing data. Thereby, the light beam is modulated according to the shape of the pattern to be drawn. The modulated light beam is incident on the surface of the substrate 9 via the imaging optical system 26 .

The imaging optical system 26 is provided with optical elements such as a first imaging lens 260, a mirror 261, an image position adjustment device 1, and a second imaging lens 262, and constitutes a reduction optical system. Through the action of these optical elements, an optical image corresponding to the shape of the pattern to be drawn is formed on the surface of the substrate 9 . Specifically, the modulated light beam forms a primary image (intermediate image) through the first imaging lens 260, and then the primary image is imaged on the surface of the substrate 9 serving as the image surface through the second imaging lens 262 to become a final image.

In addition, the imaging optical system 26 is coupled with a focus driving mechanism (not shown) that moves the second imaging lens 262 in the Z direction. The control unit 22 operates the focus driving mechanism to move the second imaging lens 262 in a direction approaching and away from the substrate 9 as indicated by the dotted arrow. Thereby, the focus of the imaging optical system 26 is adjusted in such a manner that the light beam emitted from the second imaging lens 262 converges on the surface of the substrate 9 .

The image position adjustment device 1 corresponds to an embodiment of the "optical device" of the present invention, and has the function of displacing incident light by an arbitrary distance in the X-axis direction. When the optical device of the present invention is applied to the exposure device 2, it has the function of displacing the position of the image formed on the image plane. In this sense, it has the function of an image position adjustment device. In this embodiment, the image position adjustment device 1 is disposed between the primary image produced by the first imaging lens 260 and the second imaging lens 262 . Its structure and action will be described later.

<Exposure device of second configuration example> FIG. 2 is a diagram schematically showing a second structural example of an exposure device including the optical device of the present invention. In Figure 2, the XYZ orthogonal coordinate system is also defined according to Figure 1. That is, FIG. 2 is a side view of the exposure device 4, and the direction that is horizontal and perpendicular to the paper surface of FIG. 2 is referred to as the X direction, and the direction that is orthogonal to it and is horizontal and along the paper surface of FIG. 2 is referred to as the Y direction. In addition, let the vertical downward direction be the Z direction.

As shown in FIG. 2 , the exposure device 4 includes a movable stage 40 , an exposure head 41 , a control unit 42 and a light source unit 43 . The movable stage 40 maintains the substrate 9 to be exposed in a horizontal posture, and moves in the X direction, Y direction and Z direction by the stage driving mechanism 401 . The exposure head 41 draws a fine pattern on the substrate 9 by making the modulated light beam incident on the substrate 9 . The control unit 42 controls each unit of the device by executing a pre-prepared control program to achieve predetermined actions.

The light source unit 43 is provided with, for example, a laser diode 431 as a laser light source, and an illumination optical system 432, and causes the laser beam as the exposure beam to enter the exposure head 41. The illumination optical system 432 includes a laser beam. The emitted light from the emitting diode 431 is shaped into a collimating lens of parallel light.

A spatial light modulator 410 having a diffractive optical element 411 is provided on the exposure head 41 . Specifically, the spatial light modulator 410 is installed on the upper part of the support 400 extending in the up and down direction (Z direction) of the exposure head 41, and the spatial light modulator 410 is positioned so that the reflective surface of the diffractive optical element 411 faces downward. In the state, it is supported by the support 400 via the movable table 412 .

In the exposure head 41, the diffractive optical element 411 is arranged with the normal line of its reflective surface tilted relative to the optical axis of the incident light beam. The light emitted from the light source unit 43 is incident on the reflecting mirror 413 through the opening of the pillar 400 , is reflected by the reflecting mirror 413 , and then illuminated on the diffractive optical element 411 . Then, the control unit 42 switches the state of each channel of the diffractive optical element 411 according to the exposure data, thereby modulating the laser beam incident on the diffractive optical element 411 .

Furthermore, the laser light reflected from the diffractive optical element 411 as the 0th order diffracted light is incident on the lens of the imaging optical system 414. On the other hand, the laser light reflected from the diffractive optical element 411 as the first or higher order diffracted light, Then it is not incident on the lens of the imaging optical system 414. That is, it is basically configured so that only the 0th-order diffracted light reflected by the diffractive optical element 411 is incident on the imaging optical system 414 .

The light that passes through the lens of the imaging optical system 414 is converged by the focusing lens 415 and is guided toward the substrate 9 as an exposure beam at a predetermined magnification. The imaging optical system 414 constitutes a reduction optical system. The focus lens 415 is attached to the focus drive mechanism 416 . Furthermore, the focus driving mechanism 416 moves the focus lens 415 up and down in the vertical direction (Z-axis direction) according to the control command from the control unit 42, thereby adjusting the convergence position of the exposure beam emitted from the focus lens 415 to the position of the substrate 9 upper surface.

In this way, the light beam is modulated according to the shape of the pattern to be drawn, and the modulated light beam is incident on the surface of the substrate 9 through the imaging optical system 414, thereby drawing a predetermined pattern on the surface of the substrate 9.

The image position adjustment device 1 is arranged on the optical path from the diffractive optical element 411 to the imaging optical system 414 . The structure and function of the image position adjustment device 1 are the same as those of the exposure device 2 provided in the first structural example.

FIG. 3 is a diagram showing the structure of the image position adjustment device. The image position adjustment device 1 is a combination of forming a pair of two wedge-shaped mirrors, that is, a first wedge-shaped mirror 13 and a second wedge-shaped mirror 14, thereby displacing the light beam in the X direction. The basic principle and specific design method are described in Patent Document 1, and the same design idea can also be adopted in this embodiment. Therefore, here we only briefly explain the principle and main components of the light displacement of the wedge-shaped pair 10.

The first wedge-shaped lens 13 and the second wedge-shaped lens 14 constituting the wedge-shaped lens pair 10 have substantially the same structure (for example, the vertex angle α and the refractive index n are the same), and have opposite and facing surfaces to each other. Arranged in a parallel manner at predetermined intervals. As described later, the interval is variable for adjustment of the displacement amount.

The first wedge-shaped frame 13 is fixedly supported on a suitable frame through the supporting portion 130 . On the other hand, the second wedge-shaped blade 14 is supported via the support portion 140 having the linear motion mechanism 141 . As the linear motion mechanism 141 , for example, a combination of a rotary motor and a ball screw mechanism controlled by the control unit 42 may be used, or a linear motor may be used.

The linear motion mechanism 141 moves the second wedge-shaped blade 14 in the up and down direction (Z direction) according to the control command from the control unit 42. Thereby, as shown by the dotted arrows, the second wedge-shaped arm 14 can move in the approaching direction and the away direction relative to the first wedge-shaped arm 13 within a predetermined movable range. As a result, the relative distance D1 between the two changes.

The input light Li traveling in the (+Z) direction is incident on the wedge-shaped pair 10. Specifically, the input light Li is incident on the upper side of the two wedge-shaped lenses, that is, the upper surface of the first wedge-shaped lens 13 on the (-Z) side (opposite to the opposing surface 13b of the second wedge-shaped lens 14). The non-opposing surface 13a) of the side. with symbols i represents the incident angle toward the first wedge-shaped lens 13 at this time.

The light incident on the first wedge-shaped lens 13 is refracted at the non-opposing surface 13a and the opposing surface 13b of the first wedge-shaped lens 13 respectively, with respect to the straight forward direction of the light indicated by the dotted line, at a deflection angle θ. Eject toward surface 13b. The light is further refracted by the opposing surface 14a and the non-facing surface 14b of the second wedge-shaped lens 14, and is emitted downward as the output light Lo.

The traveling direction of the output light Lo is the same (+Z) direction as the input light Li. Therefore, when the input light Li travels in a straight line without refraction, it is parallel to the output virtual light Loa, and the optical path is offset by a distance D2 in the (-X) direction relative to the optical path of the light Loa. That is, the wedge-shaped pair 10 has the function of outputting the output light Lo which displaces the input light Li in the (-X) direction. Thereby, the position of the image projected on the substrate 9 is finally changed in the X direction.

Furthermore, in the wedge-shaped mirror pair 10, light enters and exits the two wedge-shaped mirrors respectively. Therefore, in this specification, in order to avoid confusion, the light initially incident on the wedge-shaped pair 10 from the outside is called "input light", and the light finally emitted from the wedge-shaped pair 10 is called "output light".

It can be clearly seen from Figure 3 that the greater the distance D1 between the first wedge-shaped arm 13 and the second wedge-shaped arm 14, the greater the displacement D2. That is, by moving the second wedge-shaped blade 14 to change the distance D1, the displacement amount D2 can be changed. By controlling the movement amount of the second wedge-shaped lever 14 generated by the linear motion mechanism 141 by the control part 42, any displacement amount can be achieved.

Here, the light passing through the wedge-shaped pair 10 is bent in the X direction by refraction. On the other hand, the traveling direction does not change in the Y direction. Due to such anisotropy, astigmatism appears in the output light Lo. Therefore, as explained below, when the light beam is finally converged on the surface of the substrate 9 , the focus position with respect to the image plane is different in the X direction and the Y direction, which may degrade the drawing quality.

4A and 4B are diagrams showing the relationship between displacement amount and astigmatism difference. More specifically, FIG. 4A is a graph schematically showing changes in astigmatism difference when the displacement amount is changed. As described in Patent Document 1 and depicted with a plurality of dotted lines in FIG. 4A, when the distance D1 between wedge-shaped lenses is changed to change the displacement amount D2, the astigmatism difference is expressed due to the incident angle. i are different.

In the technology described in Patent Document 1, the center of the variable range of the displacement amount is used as a reference value (the displacement amount is zero), and a drawing line Pb is used in which the astigmatism difference becomes zero when the displacement amount is set to the reference value. At this time, the more the displacement deviates from the reference value, the greater the astigmatism difference. In order to avoid this situation, the incident angle is A technology is proposed to rotate wedge-shaped pairs in which i changes according to the amount of displacement.

On the other hand, in this embodiment, the drawing line Pa is used in which the astigmatism difference does not change even if the displacement amount changes. at the angle of incidence In the relationship between i and the deflection angle θ, it is known that when the incident angle is set such that the deflection angle θ is the minimum, this change in astigmatism will not occur. However, at this time, regardless of the setting of the displacement amount D2, a small astigmatism difference Da may not remain. In this embodiment, the following design concept is used to achieve zero astigmatism regardless of the displacement amount D2.

4B is a diagram schematically showing changes in the focus position of the imaging optical system when the distance D1 between wedge-shaped lenses is changed. When the distance D1 between the wedges changes, the effective optical path length changes. Therefore, the focus of the imaging optical system (the imaging optical system 26 in the first structural example, the imaging optical system 414 in the second structural example) relative to the image plane Location changes. In addition, when astigmatism difference exists, the focus position differs between the X direction and the Y direction.

However, when the incident angle is set such that the deflection angle θ is the minimum When i, the distance between the focal position in the X direction and the focal position in the Y direction is the astigmatism difference, and it is a fixed value Da regardless of the distance D1 between the wedges. Therefore, it can be considered to be different from the wedge-shaped lens pair 10, and to configure an optical element to eliminate the astigmatism difference as a "correction optical element" on the optical path, so as to eliminate the astigmatism difference.

Specifically, for example, for the astigmatism difference in which the focal position in the X direction is farther than the focal position in the Y direction, as long as the optical path is arranged so that the focal position in the Y direction is farther than the focal position in the X direction. For optical elements with astigmatism, they can be corrected by offsetting the mutual astigmatism differences. As long as the astigmatism difference generated by such optical elements is opposite in sign and has the same absolute value as the astigmatism difference generated by the wedge-shaped lens pair 10, the astigmatism difference on the image plane can eventually become zero.

As such a correction optical element, for example, an asymmetric lens whose focal lengths are different in the X direction and the Y direction can be used. For example, a cylindrical lens whose axial direction is arranged in the X direction or the Y direction only has magnification in the direction orthogonal to the axial direction, and can be suitable for the above purpose.

In this embodiment, as shown in FIG. 3 , a correction lens 15 serving as a correction optical element for the purpose of correcting such astigmatism is provided above the first wedge-shaped lens 13 . In this example, the correction lens 15 is a cylindrical lens with the Y direction being the axial direction. According to this structure, the focal position of the imaging optical system with respect to the image plane can be maintained in the Y direction while being close to the imaging optical system side in the X direction.

In order to make the astigmatism difference close to zero, the correction lens 15 is supported so that it can move up and down. Specifically, the correction lens 15 is supported by the support portion 150 having a linear motion mechanism 151 . The linear motion mechanism 151 can be implemented by, for example, a combination of a rotary motor and a ball screw mechanism, or a linear motor. The linear motion mechanism 151 operates based on the control command from the control unit 42 and moves the correction lens 15 in the up and down direction (Z direction). Thereby, the correction amount for the astigmatism difference can be adjusted, thereby achieving the condition of completely eliminating the astigmatism difference caused by the wedge-shaped lens pair 10 .

The correction effect of astigmatism difference in this embodiment can be obtained in the following manner. First, in the design stage of the device, the specifications of the first wedge-shaped lens 13 and the second wedge-shaped lens 14 are determined, and the incident angle of the input light Li relative to the wedge-shaped lens pair 10 is determined accordingly. i. Specifically, according to the method described in Patent Document 1, the vertex angle α, the refractive index n, the maximum actual displacement amount S required on the image plane, the movable range width d of the second wedge-shaped lens 14, and the image position are used. After adjusting the lens magnification M of the device 1, the specifications of the first wedge-shaped lens 13, the second wedge-shaped lens 14 and the support part 140 are determined so as to satisfy the relationship of the following equation 1. (Equation 1) Next, the incident angle of the input light Li with respect to the wedge-shaped lens pair 10 whose specifications are determined in the above manner is i is determined so as to satisfy the relationship of the following equation 2 which shows the condition that the deflection angle θ is the minimum. (Formula 2)

In this way, in this embodiment, if the specifications of the wedge-shaped pair 10 are determined, the incident angle of the input light with respect to the i is also decided during the design stage. Therefore, if the incident angle is set with sufficient accuracy during assembly or initial adjustment of the device, i, then there will basically be no need to change it thereafter.

On the other hand, in order to maximize the correction effect of the astigmatism difference (ideally make the astigmatism difference zero), the curvature radius of the cylindrical lens as the correction lens 15 and the arrangement position on the optical path need to be appropriately set. To put it more simply, by adjusting the position of the correction lens 15 in the following manner, the correction amount of the astigmatism difference can be optimized. Furthermore, although the adjustment process using the exposure device 2 of the first structural example is explained here, the same design concept can also be applied to the second exposure device 4 .

FIG. 5 is a diagram showing the structure of a device for adjusting the correction amount of astigmatism difference. In addition, FIG. 6 is a flowchart showing the processing for this adjustment. The process of optimizing the correction amount of the astigmatism difference by the cylindrical lens 15 is performed as follows. As shown in FIG. 5 , a dummy substrate 52 is arranged at a position corresponding to the image plane in place of the substrate 9 . Then, the image projected on the virtual substrate 52 is captured by the observation camera 51 . The observation camera 51 and the dummy substrate 52 may be set for this purpose, or may be set in advance for purposes such as calibration of the autofocus mechanism in the exposure head.

In order to selectively position the movable stage 20 directly below the exposure head 21 , the observation camera 51 and the virtual substrate 52 are required to move in the horizontal direction. In addition, in order to search for the focus position described later, it is required to move in the Z direction. For example, this mechanism can be installed on the side of the movable platform 20 having a moving mechanism in the same direction.

The specific processing is as follows. First, the dummy substrate 52 and the observation camera 51 are arranged in place of the movable stage 20 at the position where the exposure beam is irradiated on the image plane (step S101). In addition, the correction lens 15 is temporarily set to an appropriate reference position (step S102). The position of the second wedge-shaped blade 14 at this time is arbitrary, and for example, it can be set as the reference position.

In this state, the exposure head 21 projects the predetermined reference pattern onto the surface of the virtual substrate 52 serving as the image plane (step S103). The reference pattern is used to individually measure the focus positions in the X direction and the Y direction. For example, a combination of a line in the X direction and a line in the Y direction can be used. The projection of the reference pattern can be achieved by modulating the exposure beam by the spatial light modulation element 25, or by arranging a mask for adjustment on the optical path.

In this way, the astigmatism difference is obtained using the reference pattern projected on the surface of the virtual substrate 52 . Specifically, the observation camera 51 captures an image of the reference pattern and supplies the image data to the control unit 22 . The control unit 22 moves the observation camera 51 and the virtual substrate 52 integrally in the Z direction, and acquires the position where the reference pattern in the X direction is most clearly projected onto the image plane, that is, when the reference pattern is focused on the image plane, and the reference pattern in the Y direction. The position when focusing on the image plane (step S104), and the difference is calculated as the astigmatism difference (step S105).

If the obtained astigmatism difference is less than the preset allowable value ("YES" in step S106), since the correction of the astigmatism difference is effective, the adjustment process can be ended. On the other hand, when the astigmatism difference exceeds the preset allowable value ("NO" in step S106), the movement amount of the correction lens 15 is calculated based on its size and sign, and the correction lens 15 is moved corresponding to the movement amount. Move in Z direction (step S107). As the amount of movement of the correction lens 15, for example, a value obtained by dividing the value of the astigmatism difference calculated on the image plane by the square of the magnification of the optical system located between the image position adjustment device 1 and the image plane can be used. .

On this basis, the evaluation of astigmatism difference in steps S104 to S106 is performed again. By repeating this operation, the position of the correction lens 15 for minimizing astigmatism (ideally zero) can be driven to the optimal position.

The correction of astigmatism optimized in this way can effectively function even when the position of the second wedge-shaped lens 14 is changed. In other words, in order to achieve this purpose, the incident angle of the input light Li with respect to the wedge-shaped pair 10 i is the value at which the deflection angle θ is selected to be the smallest. Therefore, even if the position of the second wedge-shaped lens 14 is changed in order to change the displacement amount in the subsequent exposure operation, there is no need to change the position of the correction lens 15 .

This adjustment process only needs to be executed at a time point such as when the device is started, during periodic maintenance, during the operation time of the device, or when the number of substrates processed reaches a predetermined value. In addition, when, for example, the device is in a stable environment with little temperature change, in the extreme, adjustments can be made only during setup. In any case, the execution frequency will not be too high, especially it does not need to be performed during the execution of the exposure action described below.

FIG. 7 is a flowchart showing the exposure operation. When the aforementioned adjustment process has been executed, the substrate 9 to be exposed is loaded into the apparatus and placed on the movable stage 20 (step S201). Next, alignment adjustment is performed (step S202), which grasps the positional relationship between the substrate 9 on the movable platform 20 and the exposure head 21, and performs position adjustment as necessary. Well-known techniques can be applied to the alignment adjustment, so the description thereof is omitted.

Then, the movable platform 20 is moved and positioned at the predetermined exposure position (step S203), and the displacement amount of the required image is calculated (step S204). The displacement amount of the required image is used to match the amount grasped in the alignment adjustment. This corresponds to the positional deviation of the substrate 9. Based on the required displacement amount on the image plane, the required movement amount of the second wedge-shaped lens 14 is obtained (step S205). Specifically, the movement amount of the second wedge-shaped lens 14 is obtained based on the required displacement amount on the image plane and the magnification of the imaging optical system. Based on this result, the second wedge-shaped blade 14 is moved to a new position (step S206). At this time, astigmatism variation accompanying the movement of the second wedge-shaped lens 14 does not occur. Therefore, it is not necessary to move the correction lens 15 .

According to the relationship shown in FIG. 4B , changes in the distance D1 in the wedge-shaped pair 10 will cause changes in the focus position of the imaging optical system 26 . Therefore, in response to the new position of the second wedge-shaped lens 14, the Z-direction position of the imaging lens, specifically the second imaging lens 262, is changed by the focus driving mechanism (step S207).

In this state, the exposure head 21 irradiates the exposure beam modulated according to the drawing data to expose the surface of the substrate 9 (step S208) to draw a predetermined pattern. Before the drawing of the substrate 9 is completed (step S209), the processing of steps S203 to S208 is continued. Thereby, the exposure operation for one substrate 9 is completed.

As described above, the image position adjustment device 1 of this embodiment provided in the exposure devices 2 and 4 realizes the displacement of the image position in the X direction by the wedge-shaped pair of mirrors 10 . The astigmatism difference produced by the wedge-shaped lens pair 10 can be corrected by setting a correction lens 15 with different magnifications in the X direction and the Y direction. Because the incident angle of light toward the wedge-shaped lens is 10 i is set so that the deflection angle θ becomes the minimum, so even if the distance between the wedge-shaped lenses is changed, the astigmatism difference does not change. Therefore, the correction effect of the correction lens 15 on astigmatism is effective regardless of the distance between the wedge-shaped lenses. As a result, the displacement amount can be changed only by linear motion of the wedge-shaped lens without increasing astigmatism.

＜Modification＞ 8A and 8B are diagrams showing modifications of the correction optical element. FIG. 8A shows a modified example of the correction optical element using parallel plane flat plates 16 (a pair of parallel flat flat plates 16 a and 16 b ) in place of the cylindrical lens. It is known that astigmatism will occur if a parallel flat plate is arranged obliquely with respect to the optical path. Using this point, the astigmatism difference caused by the wedge-shaped lens pair 10 can be corrected. At this time, depending on whether the focal position in the X direction or the Y direction is farther, it is decided to tilt the parallel plane flat plate 16a around the X axis or around the Y axis. On the other hand, the parallel plane plate 16b is coaxial with the parallel plane plate 16a and is inclined in the opposite direction. Therefore, the parallel plane plates 16a and 16b assume a so-called figure-eight posture in which they are inclined by the same amount in opposite directions from the parallel state, so that the parallel plane plate 16b cancels the parallel displacement of the input light Li generated by the parallel plane plate 16a. Here, "tilt around the X-axis" means tilting so that the normal vector of the main surface of the parallel plane flat plate 16a has a Y-direction component but not an X-direction component. In addition, "tilt around the Y-axis" means, on the contrary, to be tilted so that the normal vector of the main surface of the parallel flat plate 16a has an X-direction component but not a Y-direction component. In addition, by providing a driving mechanism 161 for changing the magnitude of the tilt, the amount of correction for the astigmatism difference can be adjusted.

In addition, FIG. 8B shows a modified example in which the curvature variable mirror 17 is used instead of the correction optical element of the cylindrical lens. In addition, in order to retrace the optical path of the input light, a retracement mirror 171 may be appropriately provided. Even in this aspect, by using the curvature variable mirror 17 that can change the curvature (magnification) without moving the position, the astigmatism difference caused by the wedge-shaped mirror pair 10 can be corrected.

In this sense, if the reflector 246 in the exposure device 2 of FIG. 1 is a variable-curvature reflector as described above, it can also function as a correction optical element. At this time, the correction optical element does not need to be provided in the image position adjustment device 1 . In other words, the correction optical element constituting the image position adjustment device 1 is provided inside the illumination optical system 24 .

FIG. 9 is a diagram showing a modification of the exposure device of FIG. 1 . The exposure device 2A of this modified example has a correction method in which the reflection mirror 246 in the exposure device 2 of FIG. 1 is replaced by a plane reflection mirror 247, and the optical path between the plane reflection mirror 247 and the spatial light modulation element 25 is provided as a correction optical element. Structure of lens 15a. In this way, the correction optical element does not need to be placed directly in front of the wedge-shaped lens pair 10, but can be placed at an appropriate position on the optical path.

At this time, the correction lens 15 a also functions as a focusing lens for the spatial light modulation element 25 . Therefore, in the adjustment process of FIG. 6 , the "reference position" of step S102 becomes the position where the light emitted from the correction lens 15 a is focused on the spatial light modulation element 25 .

As explained above, in the aforementioned embodiment, the image position adjustment device 1 functions as the "optical device" of the present invention, and the correction lens 15, parallel plane plate 16, variable curvature mirror 17, etc. serve as the "optical device" of the present invention. "Correction optical elements" function. In addition, the support parts 130 and 140 are integrated and function as the "displacement amount adjustment mechanism" of the present invention. On the other hand, the support part 150 and the driving mechanism 161 function as the "correction amount adjustment mechanism" of the present invention.

In addition, in the exposure devices 2 and 4 of the aforementioned embodiments, the movable platforms 20 and 40 function as the "platform" of the present invention, and the platform driving mechanisms 201 and 401 function as the "moving mechanism" of the present invention. In addition, the exposure heads 21 and 41 function as the "exposure part" of the present invention.

In addition, in the above-mentioned embodiment, the X direction, which is the displacement direction of light, corresponds to the "first direction" of the present invention, and the Y direction perpendicular thereto corresponds to the "second direction" of the present invention. Here, in the above description, the emission direction of the final exposure beam is set as the vertical direction, that is, the Z direction, and the displacement direction of the image is set as the X direction. Therefore, the XYZ coordinate system is used in the description of the operation. However, in essence, there is no necessity to establish a correlation with the vertical direction, and the discussion should still be based on the direction of travel of the input light (or output light). In this case, among the directions perpendicular to the incident direction of the input light, the direction parallel to the displacement direction of the output light, and the direction perpendicular thereto can be regarded as the "first direction" and the "second direction" of the present invention respectively. .

In addition, the present invention is not limited to the above-described embodiments, and various modifications can be made in addition to the above-described embodiments as long as it does not deviate from the scope of the gist. For example, in the above-mentioned embodiment, the correction lens 15 and the like as the correction optical element are arranged on the front side of the wedge-shaped lens pair 10 in the light traveling direction, that is, on the optical path of the input light Li. However, the correction optical element may also be disposed further rearward than the wedge-shaped lens pair 10, that is, on the optical path of the output light Lo. However, as shown in this embodiment, by arranging the correction optical element on the optical path before the image displacement occurs, the incident range of the light is limited, so that the design of the optical element becomes easy.

Furthermore, in the aforementioned embodiment, the correction lens 15 as the correction optical element is a single cylindrical lens. However, for example, a correction optical element may be constructed by combining a cylindrical lens with the X direction as its axial direction and a cylindrical lens with a different focal length and with the Y direction as its axial direction. In addition, the correction optical element may be an element that has the functions of either a lens provided in the illumination optical system or the imaging optical system. In addition, for example, a concave lens, a convex mirror, etc. can also be used as the correction optical element.

In addition, in the adjustment process of the above-mentioned embodiment, the correction of the astigmatism difference of the optical element is aimed at making the astigmatism difference below a predetermined allowable value. However, the target can also be zero astigmatism difference after correction. Of course, the ideal state is zero astigmatism difference and no change.

In addition, in the aforementioned embodiment, the incident angle of the input light Li with respect to the wedge-shaped pair 10 is i is a fixed person. However, the angle of incidence i can also be variable. However, in the present invention, since there is no need to change the incident angle during operation, there is no need for a driving mechanism for changing the incident angle. For example, a mechanism for manual adjustment may be used.

In addition, in the aforementioned embodiments, the optical device of the present invention is suitable for an exposure device that exposes a substrate to draw a pattern. However, the applicable objects of the optical device of the present invention are not limited to this. The present invention is also applicable to projection devices such as projectors.

As explained above in the specific embodiments, in the optical device of the present invention, when the direction perpendicular to the incident direction of the input light and parallel to the displacement direction of the output light relative to the input light is set as the first direction, and When the direction perpendicular to the incident direction and the first direction is set as the second direction, the correction optical element may be an optical element that causes astigmatism between the first direction and the second direction. In this way, by using an optical element that has asymmetry in characteristics in two orthogonal directions, that is, anisotropy, it is possible to detect the wedge-shaped lens that is generated between the first direction and the second direction. Correction to eliminate astigmatism.

Here, as the correction optical element, for example, a lens having different focal lengths in the first direction and the second direction can be used. Alternatively, as the correction optical element, a variable curvature mirror that can change the curvature between a cross section including the first direction and a cross section including the second direction can also be used. In addition, a parallel flat plate inclined with respect to the optical path such that the normal vector of the main surface has a component in either the first direction or the second direction can also be used. Regardless of any of them, by selecting optical elements with appropriate optical characteristics, astigmatism can be corrected.

In addition, a correction amount adjustment mechanism may be further provided, which adjusts the correction amount of the astigmatism difference by moving the lens as the correction optical element in the direction along the optical path. In this way, since the correction amount can be adjusted, it can alleviate the conditions required for the optical specifications of the correction optical element.

Furthermore, for example, the correction optical element may be a parallel flat plate inclined with respect to the optical path such that the normal vector of the principal surface has a component in either the first direction or the second direction. According to this structure, by appropriately setting the thickness, refractive index, tilt, etc., astigmatism can be corrected. In this case, a correction amount adjustment mechanism that adjusts the correction amount of the astigmatism difference by changing the inclination of the correction optical element may be further provided. (industrial availability)

The present invention can be used to displace the position of a light beam or an image formed by the light beam by a predetermined amount in a predetermined direction. For example, it is applicable to the technical field of forming a pattern on various substrates, such as a printed wiring board and a glass substrate, and exposing a board|substrate.

1: Image position adjustment device (optical device) 2, 4: Exposure device 2A: Exposure device 9: Substrate 10: Wedge-shaped lens pair 13: First wedge-shaped lens 13a: Non-opposing surface 13b: Opposing surface 14: No. Two wedge-shaped lens 14a: Opposing surface 14b: Non-opposing surface 15, 15a: Correction lens (correction optical element) 16 (16a, 16b): Parallel plane flat plate (correction optical element) 17: Variable curvature mirror (correction optical element) Optical element) 20, 40: Movable platform (platform) 21, 41: Exposure head (exposure part) 22, 42: Control part 23: Light source 24: Illumination optical system 25: Spatial light modulation element 26, 414: Imaging optical system 43 :Light source unit 51:Observation camera 52:Virtual substrate 130:Support part (displacement amount adjustment mechanism) 140:Support part (displacement amount adjustment mechanism) 141:Linear motion mechanism 150:Support part (correction amount adjustment mechanism) 151:Straight motion Driving mechanism 161: driving mechanism (correction amount adjustment mechanism) 171: folding mirror 201, 401: platform driving mechanism (moving mechanism) 240: reflecting mirror 241: lens 242: optical filter 243: rod calculator 244: lens 245, 246: Reflector 247: Plane reflector 260: First imaging lens 261: Reflector 262: Second imaging lens 400: Pillar 410: Spatial light modulator 411: Diffraction optical element 412: Movable stage 413: Reflector 415: Focus lens 416: Focus driving mechanism 431: Laser diode 432: Illumination optical system Li: Input light Lo: Output light Loa: Virtual light X: First direction Y: Second direction Z: Vertical downward direction α :Vertex angle θ:Declination angle i: incident angle

FIG. 1 is a diagram schematically showing a first structural example of the exposure device. FIG. 2 is a diagram schematically showing a second structural example of the exposure device. FIG. 3 is a diagram showing the structure of the image position adjustment device. FIG. 4A is a diagram showing the relationship between displacement amount and astigmatism difference. FIG. 4B is a diagram showing the relationship between displacement amount and astigmatism difference. FIG. 5 is a diagram showing the structure of a device for adjusting the correction amount of astigmatism difference. FIG. 6 is a flowchart showing processing for adjusting the correction amount. FIG. 7 is a flowchart showing the exposure operation. FIG. 8A is a diagram showing a modified example of the correction optical element. FIG. 8B is a diagram showing a modified example of the correction optical element. FIG. 9 is a diagram showing a modification of the exposure device of FIG. 1 .

1: Image position adjustment device (optical device)

10: wedge-shaped pair

13: The first wedge-shaped quill

13a: Non-opposing surface

13b: Opposite side

14:Second wedge-shaped bow

14a: Opposite side

14b: Non-opposing surface

15: Correction lens (correction optical element)

130: Support part (displacement adjustment mechanism)

140: Support part (displacement adjustment mechanism)

141: Direct action mechanism

150: Support part (correction amount adjustment mechanism)

151: Direct action mechanism

D1: distance

D2: Displacement (distance)

Li: input light

Lo: output light

Loa: virtual light

X: first direction

Y: second direction

Z: plumb downward direction

α: vertex angle

θ: declination angle

Φi: incident angle

Claims (9)

An optical device that displaces the traveling path of input light and outputs output light along an optical path that is parallel and different from the optical path of the input light; it has: A first wedge-shaped lens, which sets the incident angle of the aforementioned input light to an angle that minimizes the deflection angle of the outgoing light; The second wedge-shaped collar has approximately the same vertex angle as the first wedge-shaped collar, and is arranged opposite to the first wedge-shaped collar, with the surface opposite to the first wedge-shaped collar being the opposite side. The aforementioned output light is emitted from the surface; A displacement adjustment mechanism supports the aforementioned first wedge-shaped arm and the aforementioned second wedge-shaped arm so that the distance between them changes to adjust the displacement; and A correction optical element is arranged in the optical path of the input light or the optical path of the output light to correct the astigmatism difference occurring in the output light. The optical device of claim 1, wherein, When the direction perpendicular to the incident direction of the input light and parallel to the displacement direction of the output light relative to the input light is set as the first direction, and the direction perpendicular to the incident direction and the first direction is set as the second direction. direction, The aforementioned correction optical element is an optical element that generates astigmatism between the aforementioned first direction and the aforementioned second direction. The optical device of claim 2, wherein, The aforementioned correction optical element is a lens with different focal lengths in the aforementioned first direction and the aforementioned second direction. For example, the optical device of claim 3 has: A correction amount adjustment mechanism adjusts the correction amount of the astigmatism difference by moving the correction optical element in a direction along the optical path. The optical device of claim 2, wherein, The aforementioned correction optical element is a variable curvature mirror that changes the curvature between a cross section including the first direction and a cross section including the second direction. The optical device of claim 2, wherein, The correction optical element is a parallel flat plate inclined with respect to the optical path such that the normal vector of the principal surface has a component in either the first direction or the second direction. For example, the optical device of claim 6 has: A correction amount adjustment mechanism adjusts the correction amount of the astigmatism difference by changing the tilt of the correction optical element. An exposure device, which has: a platform that supports a substrate for processing objects; The exposure part modulates the light beam according to the established exposure data, and makes the modulated light beam incident on the surface of the aforementioned substrate through the optical device in any one of claims 1 to 7; and A moving mechanism that relatively moves the platform and the exposure part. An exposure method is a method of exposing the substrate by making a light beam modulated according to established exposure data incident on the surface of the substrate, wherein The optical device of claim 4 or 7 is disposed on the optical path of the aforementioned light beam, and The correction amount adjustment mechanism is operated in advance to optimize the correction amount in such a manner that the astigmatism difference occurring in the output light is minimized, When the displacement amount adjustment mechanism is operated to change the displacement amount, the correction amount of the correction amount adjustment mechanism is not changed.