JP2005026528A - Projection optical system, aligner, method for adjustment, and method for exposure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection optical system which can maintain its performance even when the stroke of an actuator for regulating the focusing state of the projection optical system is reduced and the stroke of the actuator is reduced, and to provide an aligner using the same. <P>SOLUTION: The projection optical system 40 is completed by attaching units U1, U2 to an optical surface plate 73. Then, the projection optical system 40 is set in a measuring device 210, and relative positions and postures of respective partial projection optical systems PL1-PL7 are regulated, etc., and a relative alignment (coarse regulation) of image forming characteristics is performed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a projection optical system for transferring an image of a mask onto a substrate by a projection optical system, and an exposure apparatus incorporating the same, and more particularly to a scanning type multi-projection in which exposure is performed while scanning a large mask and a substrate. The present invention relates to an optical system and an exposure apparatus.
[0002]
[Prior art]
For example, when manufacturing a semiconductor element or a liquid crystal display element, a mask (reticle, photomask, etc.) pattern is projected onto a plate (glass plate, semiconductor wafer, etc.) coated with a photoresist via a projection optical system. A projection exposure apparatus is used. Conventionally, a projection exposure apparatus (stepper) that performs batch exposure of a reticle pattern on each shot area on a plate by the step-and-repeat method has been widely used. On the other hand, in recent exposure apparatuses, instead of one large projection optical system, a plurality of small partial projection optical systems are arranged in a plurality of rows at predetermined intervals in the non-scanning direction, and each partial projection optical system has a mask pattern. Has been proposed (see Patent Document 1, for example). As shown in Patent Document 2 and Patent Document 3, this type of projection optical system is composed of a lens module including a reflecting prism, a concave mirror, various lenses, and the like. This is an optical system that exposes an erect image at the same magnification through an intermediate image. In the case of the former Patent Document 2, a type using G-line and H-line for the wavelength is described, and in the case of the latter Patent Document 3, an achromatic type using G, H, and I-line is described. Naturally, increasing the wavelength and shortening the wavelength are not only for increasing the exposure power, but also for the short wavelength side due to the color resist for color filters when manufacturing liquid crystal devices in recent years. For reasons such as
[0003]
In this type of exposure apparatus, a column is arranged and fixed so that the mask stage and the projection optical system can be placed on the base. The column has a structure in which a pair of structures (so-called launchers) in which a plurality of lens modules are incorporated is supported as a projection optical system. In this way, when a plurality of lens modules are incorporated into one launcher, it is necessary to adjust the imaging state between the lens modules. Therefore, in each lens module, a focus correction unit, an image shifter unit, The current situation is that a magnification correction unit, an image rotation correction unit, and the like are provided.
[0004]
[Problems to be solved by the invention]
On the other hand, as symbolized by large liquid crystal televisions in recent years, as the size of masks and plates increases, substrates whose substrates themselves exceed 1 square meter have come to be used. For example, when such a substrate is exchanged using the projection optical system described in Example 3 of Patent Document 3, if one field is 80 mm and the size of the mask is 800 mm, there are 10 pieces. A lens module will be arranged. In this case, compared with the conventional mask size of 400 mm and the number of lens modules of 5, the launcher incorporating a plurality of lens modules is twice as large as the conventional one.
[0005]
Under such an environment, if the conventional structure is used as it is, one launcher itself is too large and heavy, so that a large deflection may occur and a large positional deviation or dimensional difference may occur with respect to transferred image information.
[0006]
In a projection exposure apparatus equipped with such a launcher, there may be a large positional shift for each exposure condition. Naturally, it is necessary to increase the stroke of an actuator such as an image shifter provided in each lens module. However, if the plane-parallel plate constituting the image shifter is tilted to a certain extent, the positional shift of each wavelength of G, H, and I becomes so large that it cannot be ignored, for example, resulting in a decrease in the contrast of the projected image. .
[0007]
Also, when assembling and adjusting using a launcher, etc., the conventional tools for adjusting the aberration of the projection lens are not sufficient, and tools and adjustment devices corresponding to the 800 mm size are necessary, requiring a large capital investment. Become. If this is a 10-lens configuration, an adjustment device of 800 mm or 1200 mm is required.
[0008]
As described in Patent Document 4, a mechanism that can adjust the position of the prism and the like so as to adjust the positional deviation and the like of the lens module can also be incorporated. Adjustments are made while considering adverse effects, requiring skill and intuition.
[0009]
[Patent Document 1]
Japanese Patent Laid-Open No. 7-57986
[Patent Document 2]
JP 2000-187332 A
[Patent Document 3]
JP 7-39557 A
[Patent Document 4]
JP 2001-337462 A
[Problems to be solved by the invention]
Accordingly, the present invention provides a projection optical system that can reduce the stroke of the actuator for adjusting the imaging state of the projection optical system itself, and that can maintain performance even when the actuator stroke is reduced, and an exposure apparatus using the same. The purpose is to provide.
[0010]
Further, the present invention reduces the increase in capital investment cost in the production of the exposure apparatus by a novel adjustment method corresponding to the upsizing of the exposure apparatus, and further, due to the effect of suppressing the initial investment amount for the exposure apparatus production, An object is to provide an exposure apparatus at a low cost.
[0011]
Another object of the present invention is to increase the productivity of the projection optical system and the like by separating the relative image adjustment of a plurality of lens modules from the adjustment of the optical performance of the projection optical system of one lens module. And
[0012]
[Means for Solving the Problems]
In order to solve the above problems, a projection optical system according to a first aspect of the present invention is a projection optical system that forms an image of a pattern on a first substrate on a second substrate, and (a) an intermediate image of a pattern on the first substrate. (B) a second imaging optical system for forming the intermediate image, and (c) supporting the first imaging optical system and the second imaging optical system. And adjusting the relative position from the reference position of at least one of the first imaging optical system and the second imaging optical system integrally to adjust the imaging characteristics of the projection optical system. And a supporting means capable of integrally adjusting a relative inclination from a reference position of at least one of the first imaging optical system and the second imaging optical system. To do.
[0013]
In the projection optical system, supporting means for supporting the first imaging optical system and the second imaging optical system includes the first imaging optical system and the first imaging optical system in order to adjust the imaging characteristics of the projection optical system. Since the relative position and the relative inclination from the reference position of at least one of the second imaging optical systems can be adjusted integrally, the first imaging optical system and the second imaging optical system can be adjusted. When these units are incorporated into the exposure apparatus as a unit, it is possible to perform simple and reliable adjustment to match them with the exposure apparatus. Since the optical components can be aligned in advance using the first imaging optical system or the second imaging optical system as a unit, the imaging characteristics of the projection optical system after being incorporated in the exposure apparatus are also good. be able to.
[0014]
According to a second invention, in the projection optical system according to the first invention, the projection optical system includes a plurality of modules each constituted by the first and second imaging optical systems and supported by the support means. Among these modules, the relative position from at least one of the first imaging optical system and the second imaging optical system constituting the module to be adjusted can be adjusted integrally. The relative inclination from the reference position of at least one of the first imaging optical system and the second imaging optical system constituting the module to be adjusted can be integrally adjusted. And In this case, the projection optical system includes a plurality of modules, and each module is constituted by the first and second imaging optical systems supported by the support means. Therefore, when incorporating these modules into an exposure apparatus, These modules can be aligned with each other. That is, since mutual alignment is possible in units of modules when the projection optical system is incorporated into the exposure apparatus, high imaging characteristics can be maintained even with a projection optical system composed of a large number of modules.
[0015]
According to a third invention, in the projection optical system of the second invention, the first and second modules constituting the plurality of modules supported by the support means based on relative imaging information between the plurality of modules. The position and inclination of at least one of the imaging optical system is adjusted. In this case, since the modules are aligned based on the imaging information of the modules themselves, simple and accurate alignment is achieved.
[0016]
A fourth invention is the projection optical system according to the second or third invention, wherein the support means is an optical surface plate that supports the plurality of modules, a plurality of the first imaging optical systems that constitute the plurality of modules, and And a plurality of position / posture adjusting members for finely adjusting the positions and postures of the plurality of second imaging optical systems on the optical surface plate. In this case, high-precision alignment is possible in which fine adjustment of each imaging optical system is performed on a stable surface plate, and the accuracy of the projection optical system can be improved.
[0017]
According to a fifth invention, in the projection optical system according to the fourth invention, the plurality of first imaging optical systems constituting the plurality of modules are fixed to one side of the optical surface plate to constitute the plurality of modules. The plurality of second imaging optical systems are fixed to the other side of the optical surface plate independently of the plurality of first imaging optical systems. In this case, the first and second imaging optical systems can be stably fixed to the optical surface plate with high density.
[0018]
A sixth invention is a projection optical system according to any one of the first to fifth inventions, wherein the projection optical system projects a pattern on the first substrate onto the second substrate at approximately the same magnification.
[0019]
According to a seventh aspect of the invention, in the projection optical system of the sixth aspect of the invention, the projection magnification of the first imaging optical system and the projection magnification of the second imaging optical system are set to be approximately reciprocal. Features. In this case, the working distance of the projection optical system can be increased without causing significant deterioration of aberrations and without increasing costs. When the first substrate and the second substrate (specifically, masks and plates) are increased in size, the amount of bending of these substrates increases. However, if the working distance is increased, they can be replaced without considering the influence of the bending. As a result, the throughput can be improved. Although the working distance can be increased by increasing the number of lenses constituting the first and second imaging optical systems or using a special lens material, an increase in cost is inevitable.
[0020]
An eighth invention is the projection optical system according to any one of the first to seventh inventions, wherein either one of the first and second imaging optical systems is integrated to adjust a relative position and inclination from a reference position. In addition to the means, a fine adjustment mechanism for adjusting at least one of image position, image rotation, focus, image plane tilt, and distortion is further provided for imaging by the first and second imaging optical systems. It is characterized by. In this case, since a plurality of modules are incorporated into the exposure apparatus while being aligned with each other by the fine adjustment mechanism, a relatively small imaging error between these modules can be additionally corrected. In addition, it is possible to easily cope with changes in exposure conditions and changes with time.
[0021]
A ninth invention is a projection optical system according to any one of the first to seventh inventions, wherein the fine adjustment mechanism includes a predetermined optical member incorporated in at least one of the first imaging optical system and the second imaging optical system. Displacement is performed with respect to position and orientation.
[0022]
A tenth aspect of the present invention is an exposure apparatus for projecting and exposing a pattern formed on a first substrate onto a second substrate, wherein the first to first elements disposed in an optical path between the first substrate and the second substrate. A projection optical system according to the ninth aspect of the invention is provided.
[0023]
In the above exposure apparatus, the first imaging optical system and the second imaging optical system are incorporated as units, and at that time, these units are incorporated while being adjusted in units of the first imaging optical system and the second imaging optical system. Therefore, a high-precision exposure apparatus can be manufactured by a simple process that does not require special equipment.
[0024]
An eleventh aspect of the invention is the exposure apparatus according to the tenth aspect of the invention, wherein the first and second substrates are moved relative to the projection optical system so that a pattern image on the first substrate is transferred to the second substrate. It further comprises scanning means for scanning above. In this case, a scanning type exposure apparatus can be provided, and a large area can be collectively exposed in the manufacture of a liquid crystal device or the like.
[0025]
According to a twelfth aspect of the present invention, there is provided a projection optical system adjustment method comprising: a projection optical system adjustment method for forming an image of a pattern on a first substrate on a second substrate; A supporting step of supporting a first imaging optical system to be formed and a second imaging optical system for forming an image of the intermediate image by supporting means; and (b) the first imaging optical system and the second connection. The relative position from the reference position of at least one of the image optical systems is integrally adjusted, and the relative position from the reference position of at least one of the first image forming optical system and the second image forming optical system is adjusted. And a correction step of adjusting the image formation characteristic of the projection optical system by integrally adjusting the relative inclination.
[0026]
In the adjustment method, in a correction step such as when the projection optical system is incorporated in the exposure apparatus, the relative position from the reference position of at least one of the first imaging optical system and the second imaging optical system Since the relative inclination is adjusted integrally, the unit composed of the first imaging optical system and the second imaging optical system can be adapted to the exposure apparatus while easily and reliably adjusting. Therefore, a high-precision exposure apparatus can be manufactured by a simple process that does not require special equipment.
[0027]
A thirteenth invention is characterized in that, in the adjustment method of the tenth invention, the imaging characteristics include at least one of an image position, an image rotation, a focus, an image plane tilt, and a distortion. In this case, it is possible to provide a highly accurate projection optical system in which these imaging characteristics are adjusted to a desired level.
[0028]
A fourteenth invention is the adjustment method of the twelfth and thirteenth inventions, wherein the projection optical system comprises a plurality of modules each constituted by the first and second imaging optical systems, and the plurality of modules A module specifying step of specifying a module to be adjusted from among the plurality of modules, wherein the supporting step supports the plurality of modules by the support means, and the correcting step includes adjusting the adjustment target among the plurality of modules. A module to be adjusted while integrally adjusting the relative position from at least one of the first imaging optical system and the second imaging optical system constituting the module to be Adjusting a relative inclination from a reference position of at least one of the first imaging optical system and the second imaging optical system to be configured integrally; And butterflies. In this case, the projection optical system includes a plurality of modules constituted by the first and second imaging optical systems supported by the support means, and the modules are sequentially installed when these modules are incorporated into an exposure apparatus. These modules can be aligned with one another while being identified. That is, since mutual alignment is possible in units of modules, high imaging characteristics can be maintained even in a projection optical system composed of a large number of modules.
[0029]
A fifteenth aspect of the invention is the adjustment method according to the fourteenth aspect of the invention, further comprising a measurement step of measuring image formation information relating to image formation characteristics of the plurality of modules, and the correction step includes the plurality of modules based on the image formation information. The position and inclination of at least one of the first and second imaging optical systems are adjusted.
[0030]
According to a sixteenth aspect of the present invention, in the adjustment method of the fifteenth aspect, the measuring step includes a step of placing a mask having an alignment mark at the position of the first substrate, and an imaging state of the alignment mark at the position of the second substrate. And a step of measuring. In this case, since the light passing through the projection optical system is measured directly using the alignment mark, the alignment between the plurality of modules becomes more accurate.
[0031]
According to a seventeenth aspect of the invention, in the adjustment method of the fourteenth to sixteenth aspects, the plurality of modules are integrally supported on an optical surface plate in the supporting step, and the plurality of modules supported on the optical surface plate in the correcting step. The position of the module on the optical surface plate is finely adjusted. In this case, high-precision alignment is possible in which fine adjustment of each imaging optical system is performed on a stable surface plate, and the accuracy of the projection optical system can be improved.
[0032]
An eighteenth invention is the adjustment method according to the seventeenth invention, wherein the supporting step fixes the plurality of first imaging optical systems constituting the plurality of modules to one side of the optical surface plate, A step of fixing the plurality of second imaging optical systems constituting the plurality of modules to the other side of the optical surface plate independently of the plurality of first imaging optical systems. . In this case, the first and second imaging optical systems can be stably fixed to the optical surface plate with high density.
[0033]
A nineteenth aspect of the invention is the adjustment method of the twelfth to eighteenth aspects of the invention, wherein the optical surface plate is aligned and fixed at a predetermined position of an exposure apparatus main body that transfers the pattern on the first substrate onto the second substrate. The method further includes a panel fixing step. In this case, the projection optical system can be incorporated into the exposure apparatus by simply fixing the optical surface plate to the exposure apparatus, and then a plurality of image forming optical systems can be finely adjusted on the optical surface plate to The consistency between modules can be improved.
[0034]
According to a twentieth aspect of the present invention, in the adjustment method according to the fourteenth to nineteenth aspects, a pre-adjustment step of measuring an image formation characteristic for each of the plurality of modules and preliminarily adjusting an image formation state of each module includes It is characterized by being done before. In this case, high accuracy of assembly can be achieved by pre-adjusting each module.
[0035]
A twenty-first invention is the adjustment method of the twelfth to twentieth inventions, wherein the predetermined optical member incorporated in at least one of the first imaging optical system and the second imaging optical system is displaced with respect to the position and orientation thereof. The image forming by the first and second image forming optical systems further includes a fine adjustment step of adjusting at least one of image position, image rotation, focus, image plane tilt, and distortion. . In this case, since a plurality of modules are incorporated into the exposure apparatus while being aligned with each other, and a relatively small imaging error between these modules can be additionally corrected, it is possible to provide a projection lens with higher accuracy. In addition, it is possible to easily cope with changes in exposure conditions and changes with time.
[0036]
An exposure apparatus according to a twenty-second invention is an exposure apparatus for projecting and exposing a pattern formed on a first substrate onto a second substrate, and is adjusted by the adjustment method of the twelfth to twenty-first inventions to adjust the first substrate and the second substrate. An exposure apparatus comprising a projection optical system disposed in an optical path between a substrate and a substrate.
[0037]
In the exposure apparatus, in a correction process such as when a projection optical system is incorporated, a relative position or a relative position from a reference position of at least one of the first imaging optical system and the second imaging optical system. Since the inclination is adjusted integrally, the unit composed of the first imaging optical system and the second imaging optical system is adapted while being adjusted easily and reliably. Therefore, a high-precision exposure apparatus can be manufactured by a simple process that does not require special equipment.
[0038]
An exposure method of the twenty-third invention is an exposure method using the exposure apparatus of the tenth, eleventh or twenty-second invention, wherein (a) of the first and second imaging optical systems supported by the support means Correcting the imaging characteristics of the projection optical system by adjusting the relative position and inclination from the reference position with at least one as one body, and (b) changing the pattern on the first substrate to the projection optical system. And a step of performing projection exposure on the second substrate.
[0039]
In the above exposure method, exposure is performed using a high-accuracy exposure apparatus in which a unit composed of the first imaging optical system and the second imaging optical system is adjusted while being adjusted easily and reliably. Can achieve high-precision exposure.
[0040]
An exposure method of a twenty-third invention comprises a step of preparing a projection optical system adjusted by the adjustment method of the twelfth to twenty-first inventions in an exposure apparatus manufacturing method for transferring a pattern on a first substrate onto a second substrate. .
[0041]
In the above exposure method, since a high-precision exposure apparatus in which a unit composed of the first image-forming optical system and the second image-forming optical system is easily adjusted and fitted is used, a high-precision exposure apparatus with a simple apparatus configuration is used. Exposure is possible.
[0042]
DETAILED DESCRIPTION OF THE INVENTION
[First Embodiment]
Hereinafter, a projection optical system and a projection exposure apparatus according to a first embodiment of the present invention will be described in detail with reference to the drawings.
[0043]
FIG. 1 is a perspective view showing an external configuration of the projection exposure apparatus according to the first embodiment. The projection exposure apparatus 10 includes an illumination device 20, a mask stage 30, a projection optical system 40, a stage device 50, and a main control device 80 that comprehensively controls the projection exposure device 10 as a whole. A scanning type exposure process is performed by projecting a pattern image formed on the mask MA onto a plate (photosensitive substrate) PT placed on the substrate.
[0044]
In the illuminating device 20, illumination light from a light source 21 such as an ultrahigh pressure mercury lamp is collected through an elliptical mirror 22, reflected by a mirror MR, and then incident on a collector lens 23. The illumination light emitted from the collector lens 23 passes through the wavelength selection filter 29a and the neutral density filter 29b for selecting the exposure wavelength that can be withdrawn from the optical path, and enters the light guide fiber FS via the relay optical system L11. The light guide fiber FS has seven exit ports, and illumination light emitted from the seven exit ports enters the seven partial illumination optical systems 28, respectively. Each partial illumination optical system 28 includes a collimator lens 28a for collimating illumination light from a corresponding exit, an integrator 28b such as a fly-eye lens for uniformizing each illumination light, and a secondary light source formed by the integrator 28b. A condenser lens 28c for superimposing and projecting the illumination light. Accordingly, it is possible to uniformly illuminate the seven trapezoidal regions (illumination field IA) arranged in two rows in the Y direction on the mask MA disposed below each partial illumination optical system 28. Here, the illuminating device 20 is not limited to the illustrated method having one light source 22 for each illumination field IA, and a number of light sources are divided into each illumination field IA by a light guide such as an optical fiber having good randomness. The light source 21 may be a light source 21, and is not limited to an ultra-high pressure mercury lamp, but may be an ultraviolet radiation type LED or LD. Further, as the light source 21, a KrF excimer laser that supplies 248 nm exposure light, an ArF excimer laser that supplies 193 nm exposure light, and F that supplies 157 nm exposure light. ₂ A laser or the like can also be used.
[0045]
The mask stage 30 has a mask holder for holding the mask MA, and further, a translation mechanism for finely moving the mask MA on the mask holder in the XY plane or finely moving in the Z-axis direction, X-axis, Y-axis It has a tilt mechanism that rotates slightly around the axis and the Z-axis. The former translation mechanism also has a scanning function for moving the mask MA at a constant speed in the X-axis direction. The operations of the translation mechanism and the tilt mechanism of the mask stage 30 are controlled by a mask driving device 31. The mask driving device 31 operates at an appropriate timing based on a control signal from the main control device 80. The replacement of the mask MA supported by the mask stage 30 is performed by a mask changer (not shown).
[0046]
The projection optical system 40 is disposed so as to face the partial illumination optical system 28 with the mask MA on the mask stage 30 interposed therebetween. The projection optical system 40 includes seven modules, that is, seven partial projection optical systems PL1 to PL7, which are arranged corresponding to the seven partial illumination optical systems 28, respectively. The light from each illumination area IA on the mask MA enters the corresponding partial projection optical systems PL1 to PL7. Among these, the odd-numbered partial projection optical systems PL1, PL3, PL5, and PL7 are arranged in a line at a predetermined interval in the Y direction orthogonal to the scanning direction, and the even-numbered partial projection optical systems PL2, PL4, and PL6. Are also arranged in a row at predetermined intervals in the Y direction. Each of the partial projection optical systems PL1 to PL7 is the same optical system of the equal magnification erecting system, and individually transfers the pattern image of the mask MA onto the plate PT. That is, an equal-size erect image of each illumination field IA is formed in each trapezoidal region (exposure field EA) arranged in two rows in the Y direction corresponding to each illumination field IA on the plate PT.
[0047]
The stage device 50 includes a stage 51 that holds the plate PT and moves together with the plate PT, a stage driving device 52 that three-dimensionally adjusts the position and posture of the stage 51, and an interference measurement fixed on the stage 51. Moving mirrors 53a and 53b are provided. Here, the stage driving device 52 can move the stage 51 on which the plate PT is placed by a large step along the X-axis direction or the like, or can move the stage 51 at a constant speed. It can be finely moved along the axis and the Z-axis direction, or can be rotated by a minute amount around these axes.
[0048]
The position coordinates and moving speed of the stage 51 are monitored by laser interferometers 54a and 54b that can perform position measurement using reflections from the movable mirrors 53a and 53b provided on the stage 51. That is, by appropriately processing the detection results of the plurality of laser interferometers 54a facing the moving mirror 53a, the position in the Y-axis direction and the rotation around the Z-axis can be detected, and the plurality of lasers facing the moving mirror 53b. By appropriately processing the detection result of the interferometer 54b, the position in the X-axis direction can be detected. The main controller 80 drives the mask driving device 31 and the stage driving device 52 based on the measurement results of the laser interferometers 54a and 54b so that the mask MA and the plate PT are precisely aligned with each other. The partial projection optical systems PL1 to PL7 can be moved at a constant speed, and so-called scanning exposure is possible. Note that the mask stage 30, the mask driving device 31, the stage 51, the stage driving device 52, and the like constitute scanning means.
[0049]
Between the odd-numbered partial projection optical systems PL1, PL3, PL5, and PL7 and the even-numbered partial projection optical systems PL2, PL4, and PL6, OFF for performing alignment of the plate PT and measurement of the baseline amount. A sensor unit 60 incorporating an axis-type plate alignment apparatus and an autofocus mechanism for measuring and controlling the focus state of the mask MA and the plate PT is disposed. Sensor unit 60 outputs the detection signal to main controller 80.
[0050]
Further, at a position adjacent to the movable mirror 53b around the plate stage, a TTL type AIS alignment for aligning the illumination fields of view IA provided on the mask MA and aligning the mask MA with the plate PT is provided. A device 63 is provided. The AIS alignment device 63 operates by being driven by the sensor driving unit 64, and outputs a detection signal to the main control device 80 via the sensor driving unit 64. The AIS alignment device 63 has a structure in which, for example, eight AIS sensors (described later) are arranged at equal intervals corresponding to the interval of the exposure field EA in the Y-axis direction.
[0051]
Further, a plurality of illuminance sensors 65 for measuring the illuminance of exposure light irradiated on the plate PT via the projection optical system 40 and its spatial distribution are provided at the end of the stage 51. These illuminance sensors 65 operate by being driven by the sensor drive unit 66, and output an illuminance signal to the main controller 80 via the sensor drive unit 66.
[0052]
FIG. 2 is a side view for explaining the mechanical arrangement of the projection exposure apparatus 10 shown in FIG. The lower base 71 is a vibration isolation base for supporting the stage device 50 and the like, and blocks the seismic intensity from the outside and prevents the propagation of vibrations generated from the stage device 50 and the local amplification. It can be done. On the base 71, a first column member 72 and a second column member 72B each having a sturdy and frame-like shape are fixed.
[0053]
On the first column member 72, an optical surface plate 73 is fixed in an aligned state. This optical surface plate 73 is a support means for aligning and fixing the projection optical system 40 integrally, and the partial projection optical systems PL1 to PL7 constituting the projection optical system 40 are divided into two on the upper surface 73a. A plurality of first units U1 which are one first imaging optical system are fixed, and a second unit U2 which is the other second imaging optical system obtained by dividing each partial projection optical system PL1 to PL7 into two on the lower surface 73b. Is fixed.
[0054]
FIG. 3 is a conceptual diagram for explaining the arrangement of the first and second units U1, U2 fixed to the optical surface plate 73. As shown in FIG. As is apparent from the figure, the first unit U1 corresponding to the front part of the odd-numbered partial projection optical systems PL1, PL3, PL5, and PL7 is equally spaced on the upper surface 73a of one half 73d of the optical surface plate 73. The second unit U2 corresponding to the rear part of the partial projection optical systems PL1, PL3, PL5, and PL7 is fixed to the lower surface 73b of the half 73d so as to face each first unit U1 at equal intervals. . Similarly, the first unit U1 corresponding to the front part of the even-numbered partial projection optical systems PL2, PL4, PL6 is fixed to the upper surface 73a of the other half 73e of the optical surface plate 73 at equal intervals, and the partial projection optical system The second unit U2 corresponding to the rear stage part of PL2, PL4, PL6 is fixed to the lower surface 73b of the same half 73e so as to face each first unit U1 at equal intervals. In addition, an opening 73f of an appropriate size is formed in the center of the optical surface plate 73 so as to incorporate the sensor unit 60 (see FIG. 1).
[0055]
Returning to FIG. 2, a support 74 that supports the mask stage 30 in a stable state is mounted on the second column member 72B. In order to load or unload the mask stage 30 together with the support body 74, the support body 74 is provided with a slide guide 75 between the second column member 72B. The slide guide 75 includes an air ball lifter and a positioning mechanism. The slide guide 75 can slide the support 74 in the X-axis direction, and the support 74, that is, the mask stage 30 is positioned at an appropriate position on the optical surface plate 73. It can be aligned and fixed.
[0056]
On the support 74, the partial illumination optical system 28 and the light guide fiber FS of the illumination device 20 are supported via another support (not shown), and are partially integrated with the mask stage 30. The illumination optical system 28 and the like can be moved. That is, by unloading the mask stage 30 together with the support 74 and retracting it from above the optical surface plate 73 and the stage apparatus 50, the internal optical surface plate 73 is opened, and the optical surface plate 73 can be attached and detached. It becomes possible. Conversely, by loading the mask stage 30 together with the support 74 and fixing it at an appropriate position above the optical surface plate 73 and the stage apparatus 50, the projection exposure apparatus 10 becomes operable, and exposure and prior alignment can be performed. Measurement is possible.
[0057]
FIG. 4 is a perspective view for explaining alignment and fixation of the first unit U1 with respect to the optical surface plate 73. FIG. For the sake of simplicity, the optical surface plate 73 shows only the area corresponding to the fixing of the first unit U1.
[0058]
On the optical surface plate 73, three pin holes 73d for fitting and fixing the alignment pins 77 are formed. When the first unit U1 is arranged on the optical surface plate 73 with the pin 77 fitted in each pin hole 73d, the bottom surface of the barrel of the first unit U1 is arranged at a predetermined position indicated by a dotted line. At this time, each pin 77 comes into contact with a reference member appropriately provided on the lens barrel of the first unit U 1, so that the first unit U 1 is precisely preliminarily aligned at a predetermined position on the optical surface plate 73.
[0059]
On the optical surface plate 73, a mounting screw 73e is also formed as a three-point seat in addition to the pin hole 73d. In a state where the first unit U1 is installed at a predetermined position on the optical surface plate 73, a fastener is inserted through a hole appropriately provided in the lens barrel of the first unit U1, and this is tightened to the screw 73e at the bottom. The first unit U1 is fixed. After fixing the first unit U1, the pin 77 is extracted from each pin hole 73d. At this time, a certain amount of play is provided between the screw 73e and the opening at the bottom of the lens barrel of the first unit U1, and the first unit U1 is slightly displaced on the optical surface plate 73 by loosening the fastener. be able to. That is, the first unit U1 can adjust the translation position in the Y direction, for example, by a minute amount, and can adjust the rotation posture around the Z axis by a minute amount. Furthermore, a spacer (foil) can be sandwiched between appropriate positions (for example, around the screw 73e) between the bottom surface of the first unit U1 and the optical surface plate 73, and by finely adjusting the thickness of the spacer, The translation position in the Z direction can be adjusted by a minute amount, and the rotational posture around the X axis and the Y axis can be adjusted by a minute amount. As a result, the first unit U1 can be slightly displaced in the Y direction, the Z direction, and the like on the optical surface plate 73, and can be slightly rotated around the Z axis, the Y axis, and the Z axis. Coarse alignment of one unit U1 becomes possible.
[0060]
In the above description, the case where the first unit U1 is fixed to the upper surface 73a of the optical surface plate 73 has been described. However, the method of fixing the second unit U2 to the lower surface 73b of the optical surface plate 73 is also as shown in FIG. It is the same. However, the second unit U2 is lifted with a simple lifter, and the second unit U2 is in contact with the optical surface plate 73 and fixed with screws from below. In this way, the second unit U2 is sequentially attached to complete the assembly of the projection optical system 40. At this time, it is not easy to loosen the screw 73e for the second unit U2 and perform rough alignment, and the workability of assembling the projection optical system 40 is reduced. Therefore, the screw 73e is loosened only for the first unit U1 to perform rough alignment. This improves the workability of alignment.
[0061]
5 and 6 are diagrams for explaining the adjustment of the distance between the plurality of first units U1. In the case of this embodiment, instead of aligning the partial projection optical systems PL1 to PL7 with an absolute reference, for example, the target of coarse alignment is gradually set on both sides based on the central partial projection optical systems PL3 and PL4, for example. Expanding. In other words, relative alignment of the partial projection optical systems PL1, PL5, PL2, PL6, etc. on both sides relative to the central partial projection optical systems PL3, PL4, etc. is sequentially relatively coarsely aligned, so that the target of completion of the coarse alignment is gradually expanded. Finally, the overall relative coarse alignment is completed.
[0062]
Therefore, a pair of screw mechanisms 78 extending from one first unit U1 is provided as a position / posture adjusting member between a pair of adjacent first units U1. These screw mechanisms 78 are attached at positions separated by a predetermined distance in the X direction in which the lens barrel extends so that the length in the Y direction can be finely adjusted. That is, the screw mechanism 78 is in a state in which the screw 73e (see FIG. 4) of one first unit U1 is loosened in advance, and the long insertion rod 15 is inserted into the gap between the first units U1 to rotate it. The amount of protrusion can be adjusted. On the other hand, a pair of reference members 16 and 17 for measuring the distance between the first units U1 are attached to the upper portions of the first units U1 so as to face each other. One reference member 16 (for example, the movable side) can be equipped with a distance measuring device 18 such as a micro sensor or a digital micrometer at two locations. The distance between the reference members 16 and 17 is increased. It can be measured with accuracy, and the displacement amount can be calculated from the difference between the measured values. Therefore, by rotating the pair of screw mechanisms 78 using the insertion rod 15 while monitoring the change in the distance between the first units U1 with the pair of distance measuring devices 18 attached to the reference member 16, Only the first unit U1 can be finely moved to adjust the distance between the first units U1. Finally, if the three screws 73e as the position / posture adjusting members of the bottom of the movable first unit U1 are tightened, the X direction with respect to the fixed first unit U1 as a reference for the movable first unit U1. Relative coarse alignment about the Z axis can be achieved.
[0063]
FIG. 7 is a diagram for explaining the internal cross-sectional structure of the partial projection optical system PL1 after assembly by the adjustment as described above. Since the other partial projection optical systems PL2 to PL7 have the same structure as the partial projection optical system PL1, description thereof will be omitted.
[0064]
The illustrated partial projection optical system PL1 includes a first imaging unit 91 that forms an intermediate image of the mask MA, and a second connection that forms a projection image of the intermediate image formed by the first imaging unit 91 on the plate PT. As a result, a pattern image in each illumination field IA on the mask MA is projected as an equal-size erect image on the exposure field EA on the plate PT. The first imaging unit 91 is an optical system part incorporated in the first unit U1 shown in FIG. 2, and the second imaging unit 92 is an optical system part incorporated in the second unit U2 shown in FIG. Here, in the vicinity of the position where the first image forming unit 91 forms the intermediate image, a field stop 93 that defines each illumination field IA on the mask MA and the exposure field EA on the plate PT is provided. The field stop 93 can be attached to the optical surface plate 73 that supports the partial projection optical system PL1, but can also be incorporated in either the first unit U1 or the second unit U2.
[0065]
The first imaging unit 91 is obliquely provided at an angle of 45 ° with respect to the pattern surface (XY plane) so as to reflect light incident along the −Z axis direction from the mask MA in the + X axis direction. A right-angle prism 91a having a reflecting surface is provided. In addition, the first imaging unit 91 includes, in order from the right-angle prism 91a side, a convex lens group including two lenses, a lens group 91c having a positive refractive power including a convex lens, and a concave lens group including two lenses. A lens group 91d having a negative refractive power and a concave reflecting mirror 91e having a concave surface directed toward the first right-angle prism 91a are provided. The lens group 91c, the lens group 91d, and the concave reflecting mirror 91e are arranged along the + X axis direction, and constitute a catadioptric optical system 91g as a whole. Light incident on the right-angle prism 91a along the −X axis direction from the catadioptric optical system 91g is −Z by the second reflecting surface obliquely provided at an angle of 45 ° with respect to the pattern surface (YX plane) of the mask MA. Reflected in the axial direction.
[0066]
On the other hand, the second imaging unit 92 has a 45 ° angle with respect to the pattern surface (YX plane) so that light incident along the −Z axis direction from the second reflecting surface of the right-angle prism 91b is reflected in the + X axis direction. A right-angle prism 92a having a first reflecting surface inclined at an angle is provided. In addition, the second imaging optical system unit 92 has, in order from the right-angle prism 92a side, a lens group 92c having a positive refractive power, a lens group 92d having a negative refractive power, and a concave surface on the first right-angle prism 92a side. And a concave reflecting mirror 92e. The lens group 92c, the lens group 92d, and the concave reflecting mirror 92e are arranged along the + X-axis direction, and constitute a catadioptric optical system 92g as a whole. Light incident on the right-angle prism 92a along the −X axis direction from the catadioptric optical system 92g is −Z by the second reflecting surface obliquely provided at an angle of 45 ° with respect to the exposure surface (YX plane) of the plate PL. Reflected in the axial direction.
[0067]
In the first imaging unit 91, in the optical path between the pattern surface of the mask MA and the first reflecting surface of the right-angle prism 91a, a pair of declination prisms 94 and 95 for focus correction and an image shifter are provided. A pair of parallel flat plates 96 and 97 are attached. Further, in the second imaging unit 92, a magnification correction optical system 98 is provided in the optical path between the second reflecting surface of the right-angle prism 92a and the exposure surface of the plate PT.
[0068]
The focus correcting deflection prisms 94 and 95 each have a wedge cross-sectional shape in the XZ plane, and one of the deflection prisms 94 and 95 is a part of the image adjustment device 99. Driven by the first driving unit 99a, and can be relatively moved along the X-axis direction. As a result, the movement of the declination prism 95 can change the optical path length between the pattern surface of the mask MA and the first reflecting surface of the right-angle prism 91a. The imaging position in the optical axis direction (Z-axis direction) by the two imaging units 92 can be changed.
[0069]
The parallel plane plates 96 and 97 as image shifters are both set to have a parallel plane perpendicular to the optical axis (Z-axis direction) in the reference state. Is driven by a second driving unit 99c, which is a portion, and is appropriately rotated by a minute amount around the Y axis, and the other parallel flat plate 97 is driven by the third driving unit 99d and is minutely moved around the X axis. Only rotate as appropriate. As described above, when one of the plane parallel plates 96 is rotated by a minute amount around the Y axis, an image formed as a result on the plate PT via the first and second imaging optical systems 91 and 92 becomes YX. Finely moving (image shift) in the X direction on the plane and rotating the other parallel flat plate 97 by a minute amount around the X axis causes the image formed on the plate PT to slightly move in the Y direction on the YX plane. (Image shift).
[0070]
The magnification correction optical system 98 includes three concave and convex lens elements arranged along the optical axis direction (Z-axis direction), and each lens element is a fourth drive unit 99e that is a part of the image adjustment device 99. So that it can be moved relatively along the optical axis direction. Thereby, the magnification of the image of the mask MA formed on the plate PT can be finely adjusted isotropically in the YX plane.
[0071]
The right-angle prism 92a on the second imaging unit 92 side is configured to function as an image rotator. That is, the right-angle prism 92a is set so that the intersection line (ridge line) between the first reflection surface and the second reflection surface extends along the Y-axis direction in the reference state, and a minute amount around the optical axis (Z-axis). It is configured to be rotatable only. When the right-angle prism 92a is driven by the fifth drive unit 99g, which is a part of the image adjustment device 99, and rotated by a minute amount around the optical axis (Z axis), the image formed on the plate PT becomes the YX plane. , The image is rotated slightly (image rotation) around the optical axis (Z-axis).
[0072]
(1) Deflection prisms 94 and 95 for focus correction, (2) Parallel plane plates 96 and 97 as image shifters, (3) Magnification correction optical system 98, and (4) Image rotator By operating the right-angle prism 92a as appropriate for each of the partial projection optical systems PL1 to PL7, the interval, size, rotation, etc. of the seven illumination fields IA provided on the mask MA are adjusted as appropriate to adjust the seven on the plate PT. The exposure field EA can be projected with fine alignment.
[0073]
In addition, detection outputs of a plurality of AIS sensors arranged below the BVU of the AIS alignment apparatus 63 provided on the stage 51 shown in FIG. 1, and the movement distances of the stages (measurement results of the laser interferometers 54a and 54b) and Therefore, the exposure field EA can be properly aligned after the assembly of the projection exposure apparatus 10, and the transfer pattern after the scanning exposure can be made continuous and smooth. Further, an optical image of a mask pattern obtained by performing measurement while moving the stage in the Z-axis direction of the optical axis and the position in the X-axis and Y-axis directions by image processing using each AIS sensor of the AIS alignment device 63. And the best focus of each point is measured.
[0074]
FIG. 8A is a view for explaining the structure of one AIS sensor 63 (1) constituting the AIS alignment apparatus 63 shown in FIG. The AIS sensor 63 (1) is formed on the mask MA by receiving an image obtained by irradiating exposure light to the position measurement index mark formed on the mask MA on the mask stage 30. This is to obtain the center (exposure center) of the projected image of the pattern, and is used when determining the baseline amount.
[0075]
In the AIS sensor 63 (1), the index plate 63a on which the reference mark IM1 is formed, that is, the BVU, is arranged so that the reference mark coincides with the upper surface of the plate PT. The index plate 63a itself on which the reference mark IM1 is formed or the optical image projected thereon is a secondary image enlarged on the two-dimensional image sensor 63e via the relay lenses 63b and 63c and the filter 63d for sensitivity correction. As projected. The two-dimensional image sensor 63e is composed of a CCD image sensor or the like, and detects an image in which the reference mark IM1 on the index plate 63a and the index mark on the mask MA are overlapped. The two-dimensional imaging device 63e transmits the detection signal to the main control device 80, and the main control device 80 performs image processing based on the detection signal from the two-dimensional imaging device 63e, and the reference mark IM1 and the mask MA The amount of deviation from the index mark is obtained.
[0076]
FIG. 8B is a diagram showing an example of the reference mark IM1 formed on the indicator plate 63a and the indicator mark IM2 on the mask MA projected on the indicator plate 63a. Such a reference mark IM1 is formed by evaporating chromium on a transparent glass substrate, for example.
[0077]
FIG. 9 is a view for explaining the structure of an off-axis type plate alignment apparatus built in the sensor unit 60 shown in FIG. The plate alignment device 62 is for measuring the position information of the reference mark IM1 (see FIG. 4) formed on the AIS alignment device 63 and the mark formed on the plate PT, and the plate PT is placed on the stage 51. This is indispensable for the exposure performed while monitoring the displacement correction and the deformation of the plate PT when mounting.
[0078]
The halogen lamp 62a incorporated in the light source unit emits light having a broad wavelength band of 400 to 800 nm with less interference. The light emitted from the halogen lamp 62a is converted into parallel light by the condenser lens 62b and then enters the dichroic filter 62c. The dichroic filter 62c is composed of a plurality of filters configured to be advanced and inserted into the optical path of the light emitted from the halogen lamp 62a. By changing the combination of the filters inserted into the optical path, a predetermined amount of incident light can be selected. Only light in the wavelength band is selected and transmitted. The light transmitted through the dichroic filter 62c enters the condenser lens 62d set so that one of the focal points is substantially disposed at the position of the incident end 62f of the optical fiber 62e. The optical fiber 62e includes one incident end and, for example, four exit ends, and each exit end is led to the illustrated alignment apparatus body A and another plate alignment apparatus body not shown. Light emitted from one exit end 62g of the optical fiber 62e is used as detection light IL1. The detection light IL1 illuminates an indicator plate 62j on which a reference mark having a predetermined shape is formed via a condenser lens 62i.
[0079]
The detection light IL1 that has passed through the index plate 62j enters the half mirror 62m that branches the illumination light and the measurement light via the relay lens 62k. The detection light IL1 reflected by the half mirror 62m is imaged on the imaging surface FC via the objective lens 62n. When a mark or the like formed on the plate PT is arranged on the image formation surface FC, the reflected light travels backward through the objective lens 62n, the half mirror 62m, and the second objective lens 62q in order, and 2 in the beam splitter 62r. One reflected light branched in the direction is imaged on the imaging surface of the low-magnification imaging device 62s provided with a CCD or the like, and the other reflected light is formed on the imaging surface of a high-magnification imaging device 62t provided with a CCD or the like. Form an image. Both imaging elements 62s and 62t are provided to measure the measurement visual field of the plate alignment device 61 at different magnifications. Both the image sensors 62s and 62t transmit their detection signals to the main controller 80, and the main controller 80 performs image processing based on the detection signals from both the image sensors 62s and 62t, and is formed on the index plate 62j. The deviation amount of the center position between the reference mark and the mark formed on the plate PT is obtained.
[0080]
FIG. 10 is a view for explaining the structure of an autofocus mechanism built in the sensor unit 60 shown in FIG. The autofocus mechanism 61 includes a light source 61a that generates inspection light, a condensing lens 61b that condenses inspection light, a pair of mirrors 61c and 61d for oblique incidence, and a condensing lens 61e that collects reflected light. The sensor 61f detects the incident position of the reflected light. Although detailed description is omitted, since the incident position of the reflected light in the sensor 61f changes according to the distance between the autofocus mechanism 61 and the surface of the plate PT, whether the in-focus state is in accordance with the position information output of the sensor 61f. It is possible to detect the amount of deviation from the in-focus state. Thereby, the upper surface of the plate PT can be aligned with the mask MA placed on the mask stage 30 with respect to the optical axis direction (Z-axis direction) of the projection optical system 40. The autofocus mechanism 61 is incorporated in the casing 60a of the sensor unit 60 together with the alignment device main body 62A of the plate alignment device 62.
[0081]
Returning to FIG. 1, the mask alignment apparatus is also incorporated in the mask stage 30, and the position information of the mask MA held on the mask stage 30 is detected. Such a mask alignment apparatus comprises a mask observation system similar to the plate alignment apparatus 62 shown in FIG. 9, and irradiates detection light to a position measurement index mark drawn outside the pattern area on the mask MA. By receiving the reflected light, the position of the index mark for position measurement is measured, and the measurement result is output to the main controller 80.
[0082]
Hereinafter, the operation of the projection exposure apparatus 10 of the first embodiment will be described. In the projection exposure apparatus 10, a mask MA is placed on the mask stage 30 in advance to perform baseline measurement. Specifically, the mask MA is first placed on the mask stage 30 to align the mask MA. Next, the position of the stage 51 in the Z-axis direction is adjusted using the autofocus mechanism 61. Next, using the AIS alignment device 63, the center (exposure center) of the projection image of the mask MA is obtained. Thereby, the relative relationship, that is, the baseline, between the image position of the mask MA and the stage 51, that is, the plate alignment device 62 can be measured. Then, alignment using the plate alignment apparatus 62 is performed, and Y, X, Y, orthogonality, and magnification of the plate PT on the stage 51 are measured. In the subsequent exposure process, the mask MA and the plate PT are synchronously moved in the X direction with respect to the projection optical system 40 based on information such as the baseline determined as described above and the movement characteristics of the stage 51. Then, scanning exposure is performed to gradually transfer the image of the mask MA over the entire surface of the plate PT.
[0083]
Hereinafter, adjustment of the projection exposure apparatus 10 of the first embodiment, particularly assembly of the projection optical system 40 will be described.
[0084]
FIGS. 11 to 16 are diagrams for specifically explaining the effect of adjustment of the projection optical system 40. In these drawings, details are omitted, but after the first and second units U1 and U2 are fixed to the upper surface 73a and the lower surface 73b of the optical surface plate 73, respectively (see FIG. 3), the first on the upper surface 73a side. The effect of finely adjusting the position and orientation of one unit U1 is described.
[0085]
FIG. 11A is a plan view of the first and second units U1 and U2, and FIG. 11B is a front view of the first and second units U1 and U2. In this case, the upper first unit U1 is slightly displaced in the −X direction by ΔX. As is apparent from the figure, the light beam traveling in the −Z direction is emitted from the straight traveling position as it is, regardless of the displacement of the first unit U1, so that the imaging position does not change. In this case, it is assumed that the field stop 93 of the projection optical system 40 is fixed to the optical surface plate 73 or the second unit U2.
[0086]
FIG. 12A is a plan view of the first and second units U1 and U2, and FIG. 12A is a side view of the first and second units U1 and U2. In this case, the upper first unit U1 is slightly displaced in the Y direction by ΔY. As is apparent from the figure, due to the displacement of the first unit U1, the light beam traveling in the −Z direction becomes a light beam that deviates from the optical axis by ΔY from the second unit U2, and the imaging position changes by 2ΔY in the Y direction. To do. Therefore, by appropriately adjusting the position of the first unit U1 in the Y direction, it is possible to align the imaging position with respect to the Y direction.
[0087]
FIG. 13 is a front view of the first and second units U1, U2. In this case, the upper first unit U1 is slightly displaced in the −Z direction by ΔZ. As is apparent from the figure, regardless of the displacement of the first unit U1, the imaging position in the focus direction hardly changes in the same magnification system. However, if the first unit U1 or the like is not completely telecentric, it is considered that a change occurs in so-called C-shaped distortion in the projected image. Therefore, it is assumed that the distortion measurement by the image processing system or the interference system can be performed by displacing the first unit U1 in the Z direction, but the distortion can be corrected between the partial projection optical systems PL1 to PL7.
[0088]
FIG. 14 is a side view of the first and second units U1, U2. In this case, the upper first unit U1 is slightly rotated around the X axis by θX. As is apparent from the figure, an image plane inclination of an angle 2θX occurs with respect to the Y direction that is the non-scanning direction. Further, it is considered that the imaging position is shifted in the non-scanning direction. Therefore, it is possible to correct the tilt of the image plane in the Y direction by appropriately adjusting the attitude of the first unit U1 around the X axis.
[0089]
FIG. 15 is a front view of the first and second units U1, U2. In this case, the upper first unit U1 is slightly rotated about the Y axis by θY. As is apparent from the figure, if the distance from the rotation center to the mask MA is L, the imaging position changes by 2LθY in the X direction. Therefore, by appropriately adjusting the attitude of the first unit U1 around the Y axis, it is possible to align the imaging position in the Y direction, that is, the scanning direction.
[0090]
FIG. 16A is a plan view of the first unit U1. In this case, the upper first unit U1 is slightly rotated around the Z axis by θZ. As shown in FIG. 16B, the exposure field EA that is the imaging position changes by 2θZ. At this time, the aberration is hardly affected. Therefore, the rotation position of the exposure field EA can be aligned by appropriately adjusting the posture of the first unit U1 around the Z axis.
[0091]
To summarize the above, the exposure field EA can be rotated or displaced in the scanning direction or the non-scanning direction by minutely changing the position and orientation of the first unit U1 on the optical surface plate 73. The imaging positions of the projection optical systems PL1 to PL7 can be adjusted with respect to each other, so that the imaging state of the projection optical system 40 can be improved. Further, distortion and image plane inclination can be corrected by fine adjustment of the first unit U1. The alignment and correction as described above are achieved by using the method shown in FIGS.
[0092]
FIG. 17A is a perspective view of a measuring apparatus 110 for measuring and adjusting each of the partial projection optical systems PL1 to PL7 as a single unit. Since this measuring apparatus 110 has a structure similar to that of the projection exposure apparatus 10, common parts are denoted by the same reference numerals, and redundant description is omitted. In this case, as shown in FIG. 17B, the first and second units constituting the partial projection optical system PL1 to be tested above and below the jig 173 having the same thickness as the optical surface plate 73 shown in FIG. Attach U1 and U2.
[0093]
The illumination device 20 is different from the projection exposure device 10 in that a single illumination optical system 28 is used. The illumination device 20 simply selects the same wavelength as the exposure wavelength, mixes this with the light guide fiber FS, and illuminates the upper test mask TM1 surface with the single illumination optical system 28. As the test mask TM1, a reticle whose position is measured or guaranteed with high accuracy is used. When the field of view of the partial projection optical system PL1 is about 80 to 100 mm, a conventional 6-inch reticle can be used. Below the test mask TM1, a support member (not shown) with an air ball mechanism and a positioning mechanism is arranged so that the partial projection optical system PL1 can be loaded and unloaded. The light transmitted through the partial projection optical system PL1 is observed by the imaging inspection unit 163 supported by the stage device 50. The stage device 50 moves along the X axis, the Y axis, and the Z axis, and the movement amount at that time is monitored by laser interference measurement. The imaging inspection unit 163 includes a mask observation system that is somewhat similar to the AIS alignment device 63 shown in FIG. 8, and performs image processing on the pattern on the test mask TM1 using the objective lens 163a and the CCD camera 163b. By using such an imaging inspection unit 163 to measure the X, Y, and Z positions on which the pattern on the test mask TM1 is projected, distortion, field aberration, spherical aberration, and the like of the partial projection optical system PL1 are measured. The coma aberration can also be measured by measuring the L / S line width using the image processing obtained by the imaging inspection unit 163. When exposure wavelength G-line, H-line, and I-line are used for measurement, chromatic aberration (longitudinal and lateral aberration) can be measured by replacing the wavelength selection interference filter 29a for selecting each emission line. .
[0094]
With the measuring device 110 using FIGS. 17A and 17B described above, the arrangement of the optical components in each of the partial projection optical systems PL1 to PL7 can be optimized. It can be corrected in units of PL1.
[0095]
FIG. 18A is a perspective view of a measuring apparatus 210 for inspecting the projection optical system 40 in which the partial projection optical systems PL1 to PL7 are assembled to the optical surface plate 73, and shows seven partial projection optical systems PL1 to PL7. It is used to adjust the relative position of. Since the measurement apparatus 210 has the same structure as the projection exposure apparatus 10, common parts are denoted by the same reference numerals, and redundant description is omitted. In this case, as shown in FIG. 18B, the first and second units U1 and U2 constituting the seven partial projection optical systems PL1 to PL7 are arranged above and below the optical surface plate 73 by the method shown in FIG. Is temporarily fixed (preliminary alignment).
[0096]
A small mercury lamp is used as the light source 21, and the illumination light from the light source 21 is guided by the light guide fiber FS and above the projection optical system 40 via a condenser lens 228 having a simple structure provided in place of the partial illumination optical system 28. Illuminate the upper test mask TM2 that is set to. The illumination optical system 28 in the above case only needs to be able to partially illuminate the mask surface of the upper test mask TM2, and in each of the partial projection optical systems PL1 to PL7, illuminates the two ends of the field area and the center. I can do it. The image of the upper test mask TM2 illuminated in this way is formed on the lower test mask TM3 which is disposed below via the projection optical system 40 and disposed at the same position as the upper test mask TM2. By superimposing the image of the upper test mask TM2 thus obtained and the image of the lower test mask TM3, image processing is used by the plurality of imaging inspection units 263 disposed below the lower test mask TM3. This makes it possible to detect misalignment. Here, each imaging inspection unit 263 includes an objective lens 263a and a CCD camera 263b. Each imaging inspection unit 263 may be arranged at a plurality of positions illuminated in advance, or may have a camera stage and may have a structure in which only the imaging inspection unit 263 can move within any one partial projection optical system PL1. . Moreover, although the example using an optical fiber was demonstrated as the illuminating device 20, for example, the black light type fluorescence which can illuminate the 800 mm width | variety of the non-scanning direction corresponding to 7-10 partial projection optical systems PL1-PL7. A tube may be used. In this case, in the two rows of partial projection optical systems PL1 to PL7, one fluorescent tube may be used on each of the odd-numbered side and the even-numbered side.
[0097]
In actual measurement, the signal from the CCD camera 263b is projected on a monitor, and the relative position is measured visually. When measuring the positional deviation using the CCD camera 263b, the position or the positional deviation may be obtained by an image processing system using electrical processing. However, the correction using the measuring device 210 may adjust the accuracy range to some extent. Therefore, it is possible to perform alignment without using an image processing system. In such rough alignment, as described with reference to FIGS. 5 and 6, the interval between the first units U1 and the like are adjusted. That is, in order to relatively align the partial projection optical systems PL1 to PL7, for example, the rough alignment target is gradually enlarged on both sides with reference to the central partial projection optical systems PL3 and PL4, for example.
[0098]
If it demonstrates to a specific alignment method, the relative position of each partial projection optical system PL1-PL7 will be first observed with the measuring device 210. FIG. For example, the upper test mask TM2 is rotated with reference to the center positions of the partial projection optical systems PL1 and PL7 at both ends. Based on this rotational position, the positions of the partial projection optical systems PL1 to PL7 are displayed on a monitor connected to the output of the CCD camera 263b and measured. Based on the measured values, the image positions and image rotation amounts, X, Y, and θZ of the partial projection optical systems PL1 to PL3, PL5 to PL7 with respect to the partial projection optical system PL4 are obtained. Based on this value, ΔθY, ΔY, ΔθZ of each of the partial projection optical systems PL1 to PL3, PL5 to PL7 is determined. When moving in the Y direction or rotating in the θZ direction, which is similar to the Z axis m, each lens is moved in the Y direction by a minute amount based on the partial projection optical system PL4, or both ends of the lens barrel, that is, on the concave mirror side Adjustment is performed by changing the amount of movement on the prism side. If this amount of movement is read by a micrometer or the like, it can be driven by a predetermined amount. Also, in the θY direction, a small amount of foil is inserted into the screw portion 73 for fixing the lens barrel itself to the optical surface plate 73 at three points, or can be exchanged in advance by a washer or the like. What is necessary is just to adjust the height of 3 points | pieces. In the case of adjustment, the upper test mask TM2 is retracted and the first unit U1 of each of the partial projection optical systems PL1 to PL7 is adjusted. In the case of adjusting the position again, the upper test mask TM2 is moved to the partial projection optical system. What is necessary is just to set according to PL4. In this way, the above operations can be repeated to roughly adjust the arrangement of the partial projection optical systems PL1 to PL7. In this embodiment, only the image positions x, y, and θ are adjusted. However, since the image plane tilt in the y direction and the C-shaped distortion can also be adjusted, the measurement device 210 is a minute amount like the projection exposure device 10. If measurement is possible, the tilt and distortion can be adjusted with high accuracy.
[0099]
FIG. 19 is a flowchart for explaining the flow of assembly and adjustment of the projection optical system 40. First, the first and second units U <b> 1 and U <b> 2 are prepared, and the partial projection optical system PL <b> 1 that is a single module is assembled using the jig 173. And it sets to the measuring apparatus 110 of FIG. 17 which is a 1st test | inspection apparatus (step S10).
[0100]
Next, while observing the imaging state with the imaging inspection unit 163 of the measuring apparatus 110, the imaging characteristics are adjusted by adjusting the positions of the optical components inside the units U1 and U2 (step S11). Such adjustment of the imaging state is also sequentially performed on the units U1 and U2 corresponding to the partial projection optical systems PL2 to PL7 other than the partial projection optical system PL1, and the aberration reduction is performed on all the partial projection optical systems PL1 to PL7. Final adjustments are made.
[0101]
Next, the adjusted units U1 and U2 are attached to the optical surface plate 73 through steps S10 and S11 to complete the projection optical system 40 (step S12). Since the assembly of the projection optical system 40 has been described in detail with reference to FIGS. 3 and 4 (preliminary alignment), detailed description thereof is omitted here.
[0102]
Next, the projection optical system 40 prepared in step S12 is set in the measurement apparatus 210 in FIG. 18 as the second inspection apparatus (step S13).
[0103]
Next, the relative position and orientation of each of the partial projection optical systems PL1 to PL7, which are modules constituting the projection optical system 40, are adjusted while observing the imaging state with the imaging inspection unit 263 of the measuring device 210. Then, relative alignment (coarse alignment or coarse adjustment) of the imaging characteristics is performed (step S14). Such relative alignment is sequentially performed for each of the partial projection optical systems PL1 to PL7 by using the method shown in FIGS.
[0104]
Next, the projection optical system 40 whose relative alignment has been completed in step S14 is incorporated into the projection exposure apparatus 10 shown in FIG. 1 and the like (step S15). At this time, the projection optical system 40 is positioned with respect to the projection exposure apparatus 10 using the optical surface plate 73 serving as the substrate of the projection optical system 40. A rotation reference (such as a hexahedron) of the optical surface plate 73 itself is provided in advance, and rotation alignment is performed using this rotation reference and is mounted on the exposure apparatus.
[0105]
Next, final alignment of the projection optical system 40 is performed using a precision alignment mechanism provided in each of the partial projection optical systems PL1 to PL7 that are modules constituting the projection optical system 40 (step S15). At this time, while monitoring the image formation state of the projection optical system 40 using the AIS alignment device 63, the declination prisms 94 and 95 for focus correction shown in FIG. 7, parallel plane plates 96 and 97 as image shifters, and the magnification By appropriately operating the correction optical system 98, the right-angle prism 92a serving as an image rotator, and the like by the image adjusting device 99, it is possible to perform precise relative alignment of the imaging states of the partial projection optical systems PL1 to PL7, and to correct aberrations. Further reduction can be achieved.
[0106]
[Second Embodiment]
Hereinafter, a method for manufacturing a micro device using the projection exposure apparatus 10 of the first embodiment in a lithography process will be described. In this case, a semiconductor device as a micro device is obtained by forming a predetermined pattern (circuit pattern, electrode pattern, etc.) on the wafer.
[0107]
FIG. 20 is a flowchart for explaining a method of manufacturing a semiconductor device as a micro device. First, in step S40 of FIG. 20, a metal film is deposited on the wafer. In the next step S42, a photoresist is applied on the metal film on the wafer to prepare a photosensitive substrate which is a wafer. Thereafter, in step S44, by using the projection exposure apparatus and method shown in FIG. 1 and the like, the pattern optical image of the mask (reticle) is projected onto the wafer (corresponding to the plate PT in FIG. 1) moved by scanning. Projected through. Thereby, an exposure pattern having a desired shape is accurately transferred to the wafer.
[0108]
Thereafter, in step S46, the photoresist layer on the wafer is developed to form a resist pattern, and in step S48, the resist pattern is used as an etching mask on the wafer to perform exposure formed on the mask. A wafer on which a circuit pattern corresponding to the pattern is formed is prepared. Thereafter, a device such as a semiconductor element is manufactured by forming an upper layer circuit pattern on a substrate on which a wafer is further processed. According to the semiconductor device manufacturing method described above, a semiconductor device having a circuit pattern having a very fine and precise line width, interval, and the like can be obtained with high throughput.
[0109]
[Third Embodiment]
Hereinafter, a method of manufacturing a liquid crystal display element as a micro device using the projection exposure apparatus 10 of the first embodiment shown in FIG.
[0110]
FIG. 21 is a flowchart for explaining a method of manufacturing a liquid crystal display element as a micro device. In this case, a liquid crystal display element as a micro device is obtained by forming a predetermined pattern on the glass substrate.
[0111]
In the pattern formation step (step S50) of FIG. 21, the pattern of the mask MA is applied to the plate PT (resist is applied) using the projection exposure apparatus shown in FIG. A so-called photolithography process is performed in which transfer exposure is performed on a glass substrate or the like. By this photolithography process, a predetermined pattern including a large number of electrodes and the like is formed on the plate PT. Thereafter, the plate PT goes through a process such as a development process, an etching process, a resist stripping process, and the like, and moves to the next color filter forming process (step S52) as a substrate on which a predetermined pattern is formed.
[0112]
In the next color filter forming step S52, a large number of sets of three dots corresponding to R, G, and B are arranged in a matrix or a plurality of sets of R, G, and B stripe filters are horizontally scanned. Color filters arranged in the line direction are formed. Then, after the color filter forming step (step S52), a cell assembling step (step S54) is executed. In this cell assembly process, a liquid crystal panel, that is, a liquid crystal cell is formed using the substrate having the predetermined pattern obtained in the pattern formation process (step S50) and the color filter obtained in the color filter formation process (step S52). assemble.
[0113]
In the cell assembly process (step S54), for example, liquid crystal is placed between the substrate having the predetermined pattern obtained in the pattern formation process (step S50) and the color filter obtained in the color filter formation process (step S52). The liquid crystal panel is manufactured by pouring. Thereafter, in the module assembly process (step S56), components such as an electric circuit and a backlight for performing display operation of the assembled liquid crystal panel are attached to complete the liquid crystal display element. According to the above-described method for manufacturing a liquid crystal display element, a liquid crystal display element having a circuit pattern having a precise line width, spacing, etc. can be obtained with high throughput.
[0114]
As described above, the present invention has been described according to the embodiment, but the present invention is not limited to the above embodiment. For example, in the projection exposure apparatus 10 of the above-described embodiment, the projection optical system is inspected by the technique shown in FIGS. 5 and 6 while inspecting the projection optical system 40 using the measuring apparatus 210 as shown in FIG. Although each module 40, that is, each of the partial projection optical systems PL1 to PL7 is aligned with each other, the same alignment is possible during the maintenance of the projection exposure apparatus 10. In other words, the entire optical surface plate 73 may be taken out from the projection exposure apparatus 10 and the same processing as steps S13 and S14 in FIG. 19 may be performed. After that, the same processing as steps S15 and S16 in FIG. 19 may be performed by resetting the projection optical system 40 after maintenance to the projection exposure apparatus 10 again. Note that the relative alignment process as in step S14 of FIG. 19 can be performed with the projection optical system 40 attached to the projection exposure apparatus 10. In this case, the mask MA on the mask stage 30 is replaced with a test mask, and the image output of the AIS alignment device 63 is used for positional deviation measurement, that is, observation of the imaging state. In addition, during the measurement of misalignment, the mask stage 30 is moved together with the support 74 and unloaded in order to perform rough alignment of the first units U1 of the partial projection optical systems PL1 to PL7 with an appropriate tool.
[0115]
In the above embodiment, a mask having a fixed mask pattern is used as the mask MA. However, a variable pattern whose transmission pattern changes with time can be used as a mask.
[0116]
In the above embodiment, the case where the exposure apparatus is basically constituted by a refractive system or a catadioptric system has been described. However, the projection optical system 40 and the like are all replaced with a reflective optical system having an equivalent or similar function. be able to.
[Brief description of the drawings]
FIG. 1 is a perspective view for explaining a projection exposure apparatus according to a first embodiment of the present invention.
FIG. 2 is a side view for explaining the mechanical arrangement of the projection exposure apparatus shown in FIG.
FIG. 3 is a diagram illustrating an arrangement of first and second units fixed to an optical surface plate.
FIG. 4 is a perspective view for explaining alignment and fixing of the first unit with respect to the optical surface plate.
FIG. 5 is a diagram illustrating adjustment of the interval between a plurality of first units.
FIG. 6 is a diagram for explaining adjustment of the interval between a plurality of first units.
FIG. 7 is a diagram illustrating a cross-sectional structure of a partial projection optical system.
8A and 8B are views for explaining the structure and the like of an AIS alignment apparatus in the alignment system shown in FIG.
9 is a diagram for explaining the structure of a plate alignment apparatus in the alignment system shown in FIG. 1; FIG.
FIG. 10 is a diagram illustrating an autofocus mechanism.
FIGS. 11A and 11B are diagrams for explaining the effect of the minute displacement ΔX of the first unit. FIGS.
FIG. 12 is a diagram for explaining the effect of a minute displacement ΔY of the first unit.
FIG. 13 is a diagram for explaining the effect of a minute displacement ΔZ of the first unit.
FIG. 14 is a diagram for explaining the effect of the minute rotation θX of the first unit.
FIG. 15 is a diagram for explaining the effect of the minute rotation θY of the first unit.
FIG. 16 is a diagram for explaining the effect of the minute rotation θZ of the first unit.
FIGS. 17A and 17B are perspective views of a measuring apparatus for measuring and adjusting each partial projection optical system alone. FIGS.
FIGS. 18A and 18B are perspective views of a measuring apparatus for measuring and adjusting a projection optical system. FIGS.
FIG. 19 is a flowchart illustrating a flow of assembly and adjustment of the projection optical system.
FIG. 20 is a flowchart for explaining a manufacturing method of a semiconductor device as a microdevice.
FIG. 21 is a flowchart for explaining a method of manufacturing a liquid crystal display element as a microdevice.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Projection exposure apparatus, 20 Illumination apparatus, 30 Mask stage, 40,140 Projection optical system, 50 Stage apparatus, 60 Alignment system, 62 Plate alignment apparatus, 63 AIS alignment apparatus, 80 Main control apparatus

Claims (24)

In a projection optical system for forming an image of a pattern on a first substrate on a second substrate,
A first imaging optical system for forming an intermediate image of a pattern on the first substrate;
A second imaging optical system for forming an image of the intermediate image;
Of the first imaging optical system and the second imaging optical system for supporting the first imaging optical system and the second imaging optical system and adjusting the imaging characteristics of the projection optical system The relative inclination from the reference position of at least one of the first imaging optical system and the second imaging optical system while allowing the relative position from at least one reference position to be adjusted integrally. Supporting means that can be adjusted integrally;
A projection optical system comprising: A plurality of modules each constituted by the first and second imaging optical systems and supported by the support means;
The support means is configured to determine a relative position from the reference position of at least one of the first imaging optical system and the second imaging optical system constituting the module to be adjusted among the plurality of modules. The relative inclination from the reference position of at least one of the first imaging optical system and the second imaging optical system constituting the module to be adjusted can be integrally adjusted while being adjustable integrally. The projection optical system according to claim 1, wherein the projection optical system is adjustable. Based on relative imaging information between the plurality of modules, the position and inclination of at least one of the first and second imaging optical systems constituting the plurality of modules supported by the support means are adjusted. The projection optical system according to claim 2. The support means includes an optical surface plate that supports the plurality of modules, and the optical surface plate of the plurality of first imaging optical systems and the plurality of second imaging optical systems that constitute the plurality of modules. The projection optical system according to claim 2, further comprising a plurality of position / posture adjusting members that finely adjust the position and posture of the projection optical system. The plurality of first imaging optical systems constituting the plurality of modules are fixed to one side of the optical surface plate,
The plurality of second imaging optical systems constituting the plurality of modules are fixed to the other side of the optical surface plate independently of the plurality of first imaging optical systems. The projection optical system according to claim 4. The projection optical system according to claim 1, wherein the projection optical system projects a pattern on the first substrate onto the second substrate at approximately the same magnification. The projection optical system according to claim 6, wherein the projection magnification of the first imaging optical system and the projection magnification of the second imaging optical system are set to be approximately reciprocal. Separately from the support means that can adjust the relative position and inclination from the reference position by integrating one of the first and second imaging optical systems, the first and second imaging optical systems 8. The image forming apparatus according to claim 1, further comprising a fine adjustment mechanism that adjusts at least one of image position, image rotation, focus, image plane tilt, and distortion. The projection optical system described in 1. 9. The fine adjustment mechanism according to claim 8, wherein a predetermined optical member incorporated in at least one of the first imaging optical system and the second imaging optical system is displaced with respect to a position and a posture. Projection optics. In an exposure apparatus that projects and exposes a pattern formed on a first substrate onto a second substrate,
An exposure apparatus comprising the projection optical system according to any one of claims 1 to 9, which is disposed in an optical path between the first substrate and the second substrate. It further comprises scanning means for scanning the pattern image on the first substrate on the second substrate by moving the first and second substrates relative to the projection optical system. The exposure apparatus according to claim 10. In a method for adjusting a projection optical system for forming an image of a pattern on a first substrate on a second substrate,
A supporting step of supporting by a support means a first imaging optical system that forms an intermediate image of a pattern on the first substrate and a second imaging optical system that forms an image of the intermediate image;
A relative position from a reference position of at least one of the first imaging optical system and the second imaging optical system is integrally adjusted, and the first imaging optical system and the second imaging A correction step of adjusting the imaging characteristic of the projection optical system by integrally adjusting the relative inclination from the reference position of at least one of the optical systems;
A method for adjusting a projection optical system, comprising: 13. The adjustment method according to claim 12, wherein the imaging characteristics include at least one of image position, image rotation, focus, image plane tilt, and distortion. The projection optical system includes a plurality of modules each constituted by the first and second imaging optical systems,
A module identifying step of identifying a module to be adjusted from the plurality of modules;
In the support step, the plurality of modules are supported by the initial support means,
In the correcting step, a relative position from at least one of the first imaging optical system and the second imaging optical system that constitutes the module to be adjusted among the plurality of modules from the reference position. The relative inclination from the reference position of at least one of the first imaging optical system and the second imaging optical system constituting the module to be adjusted is integrally adjusted. 14. The adjustment method according to claim 12, wherein the adjustment method is performed. A measurement step of measuring imaging information related to imaging characteristics of the plurality of modules,
15. The correction step according to claim 14, wherein the position and inclination of at least one of the first and second imaging optical systems in the plurality of modules are adjusted based on the imaging information. Adjustment method. The measuring step includes a step of arranging a mask having an alignment mark at a position of the first substrate, and a step of measuring an imaging state of the alignment mark at the position of the second substrate. Item 16. The adjustment method according to Item 15. In the supporting step, the plurality of modules are integrally supported on an optical surface plate, and in the correction step, the positions of the plurality of modules supported by the optical surface plate on the optical surface plate are finely adjusted. The method for adjusting a projection optical system according to any one of claims 14 to 16, wherein the adjustment method is used. The supporting step includes a step of fixing the plurality of first imaging optical systems constituting the plurality of modules to one side of the optical surface plate, and the plurality of second imaging forming the plurality of modules. The adjustment method according to claim 17, further comprising: fixing an optical system to the other side of the optical surface plate independently of the plurality of first imaging optical systems. 13. An optical surface plate fixing step of aligning and fixing the optical surface plate at a predetermined position of an exposure apparatus main body for transferring a pattern on the first substrate onto the second substrate. The adjustment method according to claim 18. 20. The pre-adjusting step of measuring the imaging characteristics for each of the plurality of modules and preliminarily adjusting the imaging state of each module is performed before the supporting step. Adjustment method described in 1. Displacement is made with respect to the position and orientation of a predetermined optical member incorporated in at least one of the first imaging optical system and the second imaging optical system, and imaging with the first and second imaging optical systems, 21. The adjustment according to claim 12, further comprising a fine adjustment step of adjusting at least one of image position, image rotation, focus, image plane tilt, and distortion. Method. In an exposure apparatus that projects and exposes a pattern formed on a first substrate onto a second substrate,
A projection optical system adjusted by the adjustment method according to any one of claims 12 to 21 and disposed in an optical path between the first substrate and the second substrate is provided. Exposure device. In the exposure method using the exposure apparatus according to claim 10, claim 11 or claim 22,
By adjusting at least one of the first and second imaging optical systems supported by the support means as a unit, the relative position and inclination from the reference position, the imaging characteristics of the projection optical system are adjusted. A process of correcting;
Projecting and exposing a pattern on the first substrate onto the second substrate via the projection optical system;
An exposure method comprising: In the manufacturing method of the exposure apparatus which transfers the pattern on a 1st board | substrate on a 2nd board | substrate, the process of preparing the projection optical system adjusted with the adjustment method as described in any one of Claim 12 thru | or 21. A manufacturing method comprising the steps of:

Images