JP3451721B2 - Projection optical apparatus, exposure apparatus having the same, and method of adjusting the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection optical system and an exposure apparatus for projecting and exposing a mask image on a plate, and more particularly to a scanning type exposure apparatus for performing projection exposure while moving the mask and the plate. The present invention relates to a projection optical system suitable for a scanning type exposure apparatus.

[0002]

2. Description of the Related Art In recent years, liquid crystal display panels have been widely used as display elements used in word processors, personal computers, televisions and the like. In manufacturing such a liquid crystal display panel, a transparent thin film electrode is patterned on a glass substrate into a desired shape by a photolithography technique.

As an apparatus for such lithography, for example, a mirror projection type aligner is known. As this aligner type exposure apparatus, for example, one shown in FIG. 10 is known. In FIG. 10, the mask M is illuminated by the arc-shaped irradiation MI by an illumination optical system (not shown). The light from this irradiation MI is
The optical path is deflected by 90 ° at the reflecting surface 71a of the trapezoidal mirror 71, and the concave mirror 72 is again passed through the concave mirror 72 and the convex mirror 73.
Is reflected at. The light from the concave mirror 72 is trapezoidal mirror 7
The optical path is deflected by 90 ° at the first reflection surface 71b, and an image PI of the irradiation MI is formed on the plate P. Further, in this aligner type exposure apparatus, the mask M and the plate P are
The images of the mask M are sequentially transferred onto the plate P by performing exposure while moving and along the Z direction in the figure.

[0004]

In the aligner type exposure apparatus as described above, when enlarging the exposure area, it may be considered that the exposure area is first divided into a plurality of areas for exposure. At this time, by preparing a plurality of masks corresponding to the plurality of divided exposure areas and performing exposure while exchanging these masks, the mask image is formed on the plurality of divided exposure areas on the plate. Are sequentially formed.

However, in this exposure method,
Since it is necessary to perform an operation of exchanging masks during the process of exposing a plurality of exposure regions, throughput is lowered, and it is necessary to accurately connect patterns between exposure regions. It becomes necessary to greatly improve the accuracy of. Next, in order to enlarge the exposure area without changing the mask, it is conceivable to use a mask larger than the field of view of the projection optical system including the concave mirror 72 and the convex mirror 73. In this case, after the mask is scanned and exposed in a predetermined visual field, the mask and the plate are moved in the direction orthogonal to the scanning direction, and then the mask is scanned in a visual field different from the predetermined visual field to enlarge the exposure area. Can be obtained by successive exposure.

However, since the image of the mask formed by the projection optical system is generally an inverted image, it is necessary to move the mask and the plate in opposite directions to perform scanning exposure. In this case, there is a problem that the mechanism for scanning the mask and the plate becomes complicated. Further, in the Offner type projection optical systems 71 to 73 as shown in FIG. 10, the lateral magnification in the scanning direction is positive, but the lateral magnification in the scanning orthogonal direction is negative. However, the above-mentioned continuous exposure cannot be achieved.

Here, in order to solve the above problems by setting the lateral magnification in the scanning direction and the lateral magnification in the scanning orthogonal direction to be positive, the projection optical system for forming the intermediate image of the mask and the light from the intermediate image are used. An exposure apparatus that includes a projection optical system that forms a secondary image of the mask is conceivable. However,
In the system using the two sets of projection optical systems as described above, there is a problem that the optical axis shift easily occurs between the two sets of projection optical systems.

Since there are various aberrations caused by manufacturing errors of the two sets of projection optical systems, after adjusting the respective projection optical systems, the two sets of projection optical systems are readjusted as a whole. It is necessary to make adjustments in consideration of the matching of distortions that occur in the optical system. Therefore, an object of the present invention is to easily perform optical adjustment such as adjustment of optical axis shift and adjustment of various aberrations.

[0009]

In order to achieve the above-mentioned object, a projection optical device according to claim 1 of the present invention comprises:
For example, as shown in FIG. 1, a projection optical system having an optical axis and two conjugate points and one of the two conjugate points of the projection optical system are arranged on the side of the conjugate point and the field of view of the projection optical system is divided. A field splitting member, and a light flux transfer member that is disposed on the other conjugate point side of the projection optical system and that transports light that has sequentially passed through the field splitting member and the projection optical system along a direction transverse to the optical axis of the projection optical system. have a, the light flux transfer member and the field of view divided member
Means that the light from the object is the field dividing member, the projection
An optical system, the light flux transfer member, the projection optical system, and the
So that it passes through the field-of-view dividing member in this order and is guided to the image plane.
Be positioned at .

In order to achieve the above-mentioned object, an exposure apparatus according to an eighth aspect of the present invention, while moving a first substrate and a second substrate in the same direction, as shown in FIG. 2, for example. An exposure apparatus for projecting a pattern of a first substrate onto a second substrate, the first reflecting surface deflecting the light passing through the first substrate, and the light passing through the first reflecting surface. , First
And an optical system for forming an intermediate image of the substrate of the substrate, the light from the first reflecting surface via the optical system is transferred along a direction transverse to the optical axis of the optical system, and the transferred light is again transmitted to the optical system. It is configured to have a light flux transfer member for guiding and a second reflecting surface for deflecting the light from the light flux transfer member via the optical system and guiding it to the second substrate.

In order to achieve the above-mentioned object, an exposure apparatus according to a ninth aspect of the present invention moves a first substrate and a second substrate in the same direction as shown in FIG. 3, for example. An exposure apparatus for projecting a pattern of the first substrate onto the second substrate, the exposure apparatus having first and second optical systems for forming an erect image of the first substrate on the second substrate. Is configured as follows. The first and second optical systems are arranged on the side of one of the projection optical system having the optical axis and two conjugate points, and the one side of the projection optical system, and deflect the light from the first substrate. A first reflecting surface guided to the projection optical system and light from the first reflecting surface via the projection optical system is transferred along a direction transverse to the optical axis of the projection optical system, and the transferred light is projected again to the projection optical system. It is configured to have a light flux transfer member for guiding to the system and a second reflecting surface for deflecting the light from the light flux transfer member via the projection optical system and guiding it to the second substrate.

According to a fourteenth aspect of the present invention, in the exposure apparatus according to the fourteenth aspect, the first substrate and the second substrate are moved in the same direction while the first substrate is patterned on the second substrate. An exposure apparatus for projecting, comprising a plurality of projection optical systems for respectively forming an erect image of the first substrate on the second substrate, and a magnification adjusting means for adjusting the magnification of the projection optical system. , Input means for inputting information regarding the expansion / contraction amount of the substrate, and control means for performing magnification control for the plurality of projection optical systems based on the information. According to a seventeenth aspect of the present invention, there is provided a method of adjusting a projection optical system according to a seventeenth aspect, wherein the step of detecting the optical axis of the projection optical system and the two visual fields of the projection optical system are spatially separated from the optical axis of the projection optical system. The step of positioning the field splitting member to be divided into two parts, and the light is sequentially transmitted through the field splitting member and the projection optical system with respect to the optical axis of the projection optical system along a direction transverse to the optical axis of the projection optical system. Positioning the light flux transporting member, the field splitting member and the light flux transporting member.
Means that the light from the object is the field dividing member, the projection
An optical system, the light flux transfer member, the projection optical system, and the
So that it passes through the field-of-view dividing member in this order and is guided to the image plane.
Be positioned at .

[0013]

In the present invention as described above, since the projection optical system can be housed in one lens barrel, there is an advantage that the misalignment of the projection optical system itself does not easily occur. In principle, the problem of the deviation does not occur. Further, in the present invention according to claim 9 , since a plurality of projection optical systems are arranged in parallel, there is an advantage that a large exposure area can be collectively scanned and exposed.
As a result, the throughput can be significantly improved. In the present invention according to claim 14, the substrate
Stretch, especially if it is partially stretched
Wear.

Here, in general, when there is a reflecting surface at the pupil position of the projection optical system, the inclination of the reflecting surface causes
Although there is a problem that the image forming position of the projection optical system moves, in the present invention, since there is no member for deflecting light at the pupil position of the projection optical system, the image forming position can be stabilized.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of a first embodiment according to the present invention. In FIG. 1, the scanning direction of the mask and the plate is the Z axis, the scanning orthogonal direction in the mask plane is the Y axis, and the normal direction of the mask and the plate is the X axis.

In FIG. 1, the illumination optical system IL includes, for example, an ultrahigh pressure mercury lamp, and exposure light (for example, g-line (435.8n
Illuminate the mask M with the wavelength m)). Where the mask M
Has a circuit pattern (not shown) and is held by the mask stage MS so that this circuit pattern is on the plate P side (lower side in the drawing). This mask stage MS
Are configured to be movable in the YZ plane in the figure. The plate P is, for example, a glass substrate whose surface is coated with a resist, and is held by a plate stage PS movably provided in the YZ plane in the drawing.

As shown in FIG. 2, the mask stage MS and the plate stage PS are integrally provided on a carriage C having a U-shaped cross section in the XY plane.
The carriage C is provided so as to be movable in the YZ plane. Returning to FIG. 1, a projection lens 20 having an optical axis along the Z direction is provided between the mask M and the plate P. Then, on one side of the projection lens 20,
A reflecting member 10 having a reflecting surface 10a obliquely arranged at 45 ° with respect to the mask M and a reflecting surface 10b obliquely arranged at 45 ° with respect to the plate P is provided. Further, on the other side of the projection lens 20, as a light flux transfer member, a reflecting surface 13a obliquely provided at 45 ° with respect to the optical axis of the projection lens 20.
And a reflecting member 15 having a reflecting surface 15a inclined at 45 ° with respect to the optical axis of the projection lens 20. Here, the reflecting surface 13a and the reflecting surface 15
The a is provided so that the surfaces thereof are orthogonal to each other.

The projection lens 20 has lens components L ₁ to
A front group G _F having L ₄ as a whole and having a positive refracting power, an aperture stop AS that defines the numerical aperture of the projection lens 20, and a rear group G having positive refracting power as a whole and having lens components L _{5 to} L _{8. With R} and. In this embodiment, the front group G _F and the rear group G _R are
The same configuration is used, and the rear focus position of the front lens group G _F and the front focus position of the rear lens group G _R are arranged so as to be at the position of the aperture stop AS. Therefore, the projection lens 20 is a two-sided telecentric optical system.

The reflecting member 10 is fixed to the main body of the exposure apparatus.
The reflecting member is attached to the support member 11 provided.
Similarly, 13 and 15 are supporting portions fixed to the main body of the exposure apparatus.
It is attached to the material 16. In addition, the projection lens 20
Each lens component L₁~ L₈And the aperture stop
It is attached to the lens barrel 12 fixed to the. Well, Teru
The light from the mask M illuminated by the bright optical system IL is
The optical path is deflected by 90 ° on the projection surface 10a, and the projection lens 2
0 along the optical axis direction (Z direction), the projection lens 2
Lens component L of 0₁Reach This light is the lens component L
₁~ L _FourAnd the aperture stop AS are reached. Open
The light that has passed through the aperture stop AS has a lens component L._Five~ L₈In order
After passing the next time, it is emitted parallel to the optical axis of the projection lens 20.
Be done. The light emitted from the projection lens 20 is reflected by the reflecting surface 13
The optical path is deflected by 90 ° at a and is fixed to the support member 16.
To the field stop 14. Here, the field stop 14 is
It is provided at a position conjugate with the mask M with respect to the shadow lens 20.
Therefore, an intermediate image of the mask M is formed here.
This intermediate image has a lateral magnification of -1 in the Y direction and is in the Z direction.
Has a lateral magnification of +1.

Next, the light from the intermediate image on the field stop 14 has its optical path deflected by 90 ° through the reflecting surface 15a, travels in parallel with the optical axis of the projection lens 20, and has a lens component L of the projection lens 20. Reach _eight This light is the lens component L _{8 to} L
₅ , after sequentially passing through the aperture stop AS and the lens components L _{4 to} L ₁ , the light is emitted parallel to the optical axis of the projection lens 20. The light from the projection lens 20 travels along the optical path 90 at the reflecting surface 10b.
Deviated to reach the plate P. Here, since the field stop 14 and the plate P are arranged so as to be conjugated with respect to the projection lens 20, a secondary image of the mask M is formed on the plate P. The intermediate image of the mask M is an erect normal image with a lateral magnification of +1 in the Y and Z directions. As described above, in this embodiment, the erect image is obtained by reflecting the light four times on the reflecting surface and forming the image twice by the projection lens.

In the above embodiment, the front group G _F
And the rear group G _R have the same configuration. That is, since the focal length of the front lens group G _{F and} the focal length of the rear lens group G _R are the same, the mask M and the intermediate image on the field stop 14 have the same size, and the intermediate image on the field stop 14 and the plate P are the same. The secondary image above is the same size. However, in the present embodiment, even when the focal lengths of the front group G _F and the rear group G _R are different, the magnification relationship between the mask M and the secondary image on the plate P is equal. That is, the mask M and the field stop 14
Even if the magnification relationship with the above intermediate image is β (≠ ± 1), the magnification relationship between this intermediate image and the secondary image on the plate P is 1 / β.
Therefore, as a whole, the mask M and the plate P
It can be seen that the magnification relationship with the upper secondary image is 1 ×.
For example, if the magnification of the mask M and the intermediate image on the field stop 14 is increased, the reflecting surfaces 10a and 10b of the reflecting member 10 are
The distance (working distance) between the mask M and the plate P can be increased. As described above, the projection optical system according to the present embodiment has an advantage that the degree of freedom in optical design is high.

The exposure operation in the first embodiment will be briefly described below with reference to FIG. In the following description, by dividing the above mask M into three regions m ₁ ~m _3, three regions p ₁ ~p on the region m ₁ ~m ₃ plates P
An example of exposing to ₃ is shown. During the second and subsequent exposures of the plate P, first, an alignment optical system (not shown) is used to detect the positional deviation between the mask M and the plate P, and based on the detection result, the mask stage MS or the plate stage PS is detected. At least one of them is moved in the YZ plane for alignment.

After that, the carriage C is driven so that the end of the area m ₁ of the mask M in the Z direction and the end of the area p ₁ of the plate P in the Z direction are positioned within the visual field of the projection lens 20. To position. Then, the carriage C is moved at a predetermined speed along the Z direction (scanning direction) while irradiating the mask M by the illumination optical system IL (not shown) in FIG. As a result, the area p on the plate P is
_{At 1} , the images of the region m ₁ of the mask M are sequentially formed.

Next, the carriage C is moved along the Y direction (scanning orthogonal direction) in the figure, and the area m ₂ on the mask M is
The positioning is performed so that the area p ₂ on the plate P coincides. After that, the carriage C is moved at a predetermined speed in the Z direction (scanning direction) to sequentially form an image of the area m ₂ of the mask M on the area p ₂ of the plate P. Finally, the carriage C is moved along the Y direction (scanning orthogonal direction) in the drawing, and the region m ₃ on the mask M and the region p ₃ on the plate P are moved.
Position so that and match. After that, the carriage C is moved along the Z direction (scanning direction) at a predetermined speed to successively form an image of the area m ₃ of the mask M on the area p ₃ of the plate P.

Here, in the above-mentioned exposure operation, the carriage C during the scanning exposure of the regions m ₁ and m ₃ of the mask M
The moving direction of the carriage C and the moving direction of the carriage C during the scanning exposure of the area m ₂ of the mask M are different by 180 °. Note that the positioning operation using an alignment optical system (not shown) may be omitted when the plate P is exposed for the first time.

Further, in the above-mentioned embodiment, the carriage C is provided so as to be movable in the YZ plane, but when the carriage C is movable only in the Z direction, the mask stage MS and the plate stage PS are Can be made equivalent to the movement of the carriage C in the Y direction. In the above embodiment, the projection lens 2
When 0 is a one-sided telecentric optical system, in order to achieve telecentricity at least on the plate P side, a reflecting member 10 as a field dividing member is provided on the telecentric side, and a reflecting member 13 is provided on the non-telecentric side. , 15 should be provided. This allows
Telecentricity is achieved on the mask M side and the plate P side. At this time, the reflection surfaces 13a and 15a of the reflection members 13 and 15 have an angle formed by the reflection surfaces 13a and 15a that is the principal ray of the light beam traveling from the projection lens 20 to the reflection surface 13a and the reflection surface 15a to the projection lens 20. It may be provided so that the principal ray of the light flux directed toward the projection lens 20 is symmetrical with respect to the optical axis thereof. In the one-sided telecentric optical system as described above, since the magnification of the secondary image of the mask M on the plate P may be partially different in the Z direction, the projection lens 20 is composed of a two-sided telecentric optical system. Preferably.

In the embodiment shown in FIGS. 1 and 2, the exposure is performed by the operation of moving the mask M and the plate P in the direction orthogonal to the scanning, but a plurality of projection optical systems are provided to perform the scanning once. Exposure can also be performed at. A second embodiment having a plurality of projection optical systems will be described below with reference to FIG. FIG. 3 is a schematic diagram showing the arrangement of a plurality of projection optical systems. In FIG. 3, members having the same functions as those shown in FIGS. 1 and 2 are designated by the same reference numerals,
The same coordinate system as in FIGS. 1 and 2 is used.

In FIG. 3, five projection optical systems 21 to 25 are provided in the space between the mask M and the plate P. In this embodiment, the projection lens 20 of FIG.
The entire optical system including the reflecting member 10, the reflecting members 13 and 15 and the field stop 14 is referred to as a projection optical system. Then, the projection optical systems 21 to 25 form erect normal images of the same size as the visual field regions ML _{1 to} ML ₅ on the mask M on the exposure regions PL _{1 to} PL ₅ on the plate P, respectively.

The projection optical systems 21 to 23 have a visual field region ML ₁
~ ML ₃ is provided so as to be arranged along the Y direction,
In the projection optical systems 24 and 25, the visual field regions ML ₄ and ML ₅ are Y
It is provided so as to be arranged along the direction. At this time,
A position in the Z direction where the visual field regions ML _{1 to} ML ₃ are arranged,
It is different from the position in the Z direction where the visual field regions ML ₄ and ML ₅ are arranged. In addition, in FIG. 3, the shape of each of the visual field regions ML _{1 to} ML ₅ and each of the exposure regions PL _{1 to} PL ₅ is illustrated as a slit shape (rectangular shape), but this shape has each visual field region M.
The shape may be such that the sum of the lengths of L _{1 to} ML _{5 in} the Z direction (scanning direction) is always the same in the Y direction (scanning orthogonal direction). Specifically, a hexagonal shape, an arc shape, a trapezoidal shape, or the like can be considered. This shape will be described later in detail.

During actual exposure, the mask M is illuminated by an illumination optical system (not shown), and the mask M and the plate P are moved integrally along the Z direction, so that the visual field regions ML _{1 to} ML ₅ are masked. The entire surface of M is scanned, and the exposure regions PL _{1 to} PL ₅ scan the entire surface of plate P. As a result, the image of the mask M is sequentially formed on the plate P.

In this embodiment, the projection optical systems 21 to 2 are used.
3 and the projection optical systems 24 and 25 are provided so that the reflecting members 13 and 15 as the light flux transfer members face the opposite sides, and therefore the exposure regions PL _{1 to} PL ₃ and the exposure regions PL ₄ and
The distance from PL ₅ in the scanning direction can be reduced, which is convenient in terms of arrangement. It goes without saying that the number of projection optical systems is not limited to five in the above embodiment.

Further, the projection lens 20 according to the present embodiment is
It is preferable to satisfy the following conditions.

[0033]

Φ / 2> d (1) where φ is the maximum lens diameter of the projection lens 20, and d is the working distance of the projection lens 20. It should be noted that the working distance d is obtained when the bending of the optical path by the reflecting surface 10a of the reflecting member 10 is ignored, as shown in FIG. 4 (a) which is an enlarged view of the mask M and plate P side of the projection optical system. It is a thing.

When the projection lens 20 does not satisfy the relation of the conditional expression (1), the mask M and the projection lens 20
(Or the lens barrel 12) interferes with each other, which is not desirable. Further, in the present embodiment, the field of view of the projection lens 20 is set to the reflection member 1.
Since it is divided into two by 0, vignetting occurs in the visual field region near the optical axis of the projection lens 20 as shown in FIG. 5 (a). In FIG. 5A, the entire field of view of the projection lens 20 is shown by a broken line, and the effective field of view (field without vignetting) of the projection lens 20 is shown by hatching. In FIGS. 4A and 5A, the length Y ₁ min of the vignetting area on the mask M surface or the plate P surface in the X direction is the distance between the apex of the reflecting member 10 and the object point of the projection lens 20. D _L ,
Let NA _{1 be} the numerical aperture of the projection lens 20, and NA ₁ = sin
When the angle which is obtained by theta ₁ and theta _1, represented by the following conditional expression (2).

[0035]

[Equation 2] Y ₁ min = d _L · tan θ ₁ (2) However, the position of the object point of the projection lens 20 shown in FIG. 4A and the field of view of the projection lens 20 shown in FIG. This is a case where the bending of the optical path by the reflecting surface 10a of the reflecting member 10 is ignored as indicated by the broken line.

On the intermediate image side of the projection lens 20, since the light flux is transferred by the reflecting members 13 and 15 in the direction crossing the optical axis of the projection lens 20, as shown in FIG. 5 (b). Vignetting occurs in the visual field region on the 20th intermediate image side. In FIG. 5B, the entire visual field region on the intermediate image side of the projection lens 20 is represented by a broken line, and the effective visual field (region without vignetting) of the projection lens 20 is represented by hatching. 4B and 5B, the length Y ₂ min of the vignetting area in the intermediate image plane in the X direction is defined by the distance between the projection lens 20 and the intermediate image plane d _M , and the aperture of the projection lens 20. the number and NA _2, when the angle which is obtained by NA ₂ = sinθ ₂ and theta _2, is expressed by the following conditional expression (3).

[0037]

[Equation 3] Y ₂ min = d _M · tan θ ₂ (3) However, the distance between the projection lens 20 shown in FIG. 4 (b) and the intermediate image plane and the field of view of the projection lens 20 shown in FIG. 5 (b) are , When the bending of the optical path by the reflecting members 13 and 15 is ignored.

As described above, in the projection optical system according to the present embodiment, the visual field area and the exposure area that can be used are the areas where the two effective visual fields shown in FIGS. 5 (a) and 5 (b) overlap. Therefore, it is desirable that the area of the opening of the field stop 14 be within the area where the effective fields of view overlap. Figure 6 below
The relationship between the shape of the opening of the field stop 14 and the effective field of the projection lens 20 is shown in FIG. In FIG. 6, the effective field of view of the projection lens 20 on the plate P is shown by a broken line, and the image of the opening of the field diaphragm 14 projected by the projection lens 20 is shown by a solid line. Here, the effective visual field of the projection lens 20 refers to a region where the two effective visual fields shown in FIGS. 5 (a) and 5 (b) overlap.

FIG. 6A shows the case where the field stop 14 has a slit-shaped opening. For example, when scanning exposure is performed once with one projection optical system, such a slit-shaped opening is preferably used. FIG. 6 (b) shows the case where the field stop 14 has a hexagonal opening, and FIG.
Shows the case where the field stop 14 has an arcuate opening, and FIG. 6D shows the case where the field stop 14 has a trapezoidal opening. As described above, the openings shown in FIGS. 6B to 6D have portions in which the lengths of the openings in the Z direction (scanning direction) are not constant. For example, when the scanning exposure is performed twice or more by one projection optical system as shown in FIG. 2 or when the scanning exposure is performed once by the plurality of projection optical systems as shown in FIG. It suffices to set a portion where V is not constant as an overlap region. The overlap region refers to a region where a plurality of exposure regions overlap with each other. At this time, the sum of the lengths of the plurality of openings in the overlap region in the Z direction is always equal in the Y direction (scanning orthogonal direction). As a result, the exposure amount difference between the plurality of exposure regions is always zero.

Here, as shown in FIGS. 6A to 6D, the opening of the field stop 14 is provided so as to be located within the effective field of the projection lens 20. Next, with reference to FIG. 7, an embodiment of a projection optical system incorporating an optical member for correcting an error due to an environmental change will be described. FIG. 7 is a diagram showing the configuration of the projection optical system of the present embodiment, which employs the same coordinate system as in FIG. In FIG. 7, members having the same functions as those in the embodiment of FIG. 1 are designated by the same reference numerals.

In FIG. 7, a configuration different from that of the projection optical system of FIG. 1 is a pressure for changing the pressure of the gas enclosed in a specific space between the plurality of lens components L _{1 to} L ₈ forming the projection lens 20. The adjusting part 30 and the reflecting surface 10 of the reflecting member 10.
This is a point having a pair of parallel plane plates 33, 34 provided in the optical path between a and the plate P. The pressure adjusting unit 30 shown in FIG. 7 controls the pressure in the lens chamber 31, which is a sealed space between the lens component L ₁ and the lens component L ₂ , by the pipe 3
2 to change the refractive index of the lens chamber 31 to change the projection magnification and the focus position of the projection lens 20. The specific configuration of the pressure adjusting unit 30 is disclosed in Japanese Patent Application No. 58-186267 filed by the same applicant as the present applicant, and therefore the description thereof is omitted here.

In the embodiment shown in FIG. 7, a control unit 35 for controlling the pressure adjusting unit 30 and an input unit 36 such as a keyboard for inputting information on a desired projection magnification.
And further. In addition, the control unit 35 includes a lens chamber 31.
Pressure and projection magnification (lateral magnification of secondary image for mask M)
A reference table that stores the relationship between the reference pressure table and the reference table is provided, and the control unit 35 refers to this reference table and the information regarding the magnification from the input unit 36 to determine that the pressure in the lens chamber 31 is a predetermined projection magnification. The pressure adjusting unit 30 is controlled so that

Next, due to the pressure change in the lens chamber 31,
The relationship between the change amount of the focal length due to the pressure change when the focal length of the front group G _F changes from f to f + Δ, and the change amount of magnification and the change amount of the image plane position will be described. In reality, there are lens chambers that strongly affect the change in projection magnification and lens chambers that strongly change the image plane position due to the refractive power of each lens component that constitutes the projection lens 20. However, here, in order to simplify the description, the focal lengths of the front lens group G _F and the rear lens group G _R of the projection lens 20 are both set to f, and the front lens group G _F and the rear lens group G _R are thinly approximated. Will be explained.

As described above, when the focal length of the front lens group G _F changes from f to f + Δ, the magnification change and image plane position variation at the intermediate image position are different from those of the front lens group G _F and the rear lens group G _R. Applying the lens formula, it is shown as follows. First, the image plane position variation of the intermediate image is

[0045]

[Equation 4]         f {(f + 3Δ) / (f + 2Δ) -1} (4) And the magnification of the intermediate image is

[0046]

[Equation 5] − (f + Δ) / (f + 2Δ) (5) Further, the image plane position variation of the secondary image is shown as follows,

[0047]

F ((f + 3Δ) (f + Δ)} / {f (f + 3Δ) −Δ (f + Δ)} (6) The magnification of the secondary image at the secondary image plane position, that is, the projection magnification is

[0048]

(F + Δ) ² / {f (f + 3Δ) −Δ (f + Δ)} (7) Therefore, if the change amount of the focal length of the front lens group G _F due to the pressure change of the lens chamber 31 can be calculated, the magnification of the secondary image at the secondary image plane position can be obtained, and further,
The amount of change in the image plane position of the secondary image can also be obtained. When the image plane position of the secondary image changes, the secondary image on the plate P is in a defocused state. At this time, the mask M, the plate P, or both are moved along the X direction in the figure. You can do it. Further, in the projection optical system of FIG. 7, one lens chamber for changing the pressure is provided, but the number of lens chambers for changing the pressure is not limited to one. For example, if two lens chambers are provided, it is possible to change only the projection magnification while making the image plane position variation of the secondary image represented by the above formula (7) zero. In the projection optical system of FIG. 7, a lens chamber for changing the pressure is provided only in the front group G _F , but a lens chamber for changing the pressure may be provided in the rear group G _R.

Further, in the projection optical system shown in FIG.
A pair of parallel plane plates 33 and 34 are provided in the optical path between the reflecting surface 10b of the reflecting member 10 and the plate P. Figure 7
In, the parallel plane plate 33 is provided so as to be swingable about the Y direction as a rotation axis, and the parallel plane plate 34 is provided so as to be swingable about the Z direction as a rotation axis. Here, by swinging the plane-parallel plate 33 so as to incline with respect to the plate P, the position of the secondary image with respect to the visual field of the projection optical system can be moved in the Z direction. Further, by swinging the plane-parallel plate 34 so as to be inclined with respect to the plate P, the position of the secondary image with respect to the visual field of the projection optical system can be moved in the Y direction.

Instead of oscillating the plane-parallel plate, a pair of deflection prisms having a wedge-shaped cross-section are provided on the reflecting surface 1.
It is also possible to move the position of the secondary image by providing it in the optical path between 0b and the plate P and changing the interval between these declination prisms. Here, the pair of deflection angle prisms are configured to have a plane having a predetermined apex angle,
The vertices are provided so that their vertices face in opposite directions.

The operation of moving the position of the secondary image as described above is performed when one scanning exposure is performed by one projection optical system or by one projection optical system such as the embodiment shown in FIGS. It is not essential when performing multiple scanning exposures. However, when scanning exposure is performed once with a plurality of projection optical systems as shown in FIG. 3, it is preferable to provide a pair of parallel plane plates 33 and 34.

The embodiment shown in FIG. 3 is suitable for manufacturing a large-screen liquid crystal panel, for example, and in manufacturing such a large-screen liquid crystal panel, the plate P may expand and contract depending on the process. Therefore, for example, the size of the plate P during the first exposure and the size of the plate P during the second exposure change. At this time,
The projection adjusting magnification (magnification of the secondary image on the plate P with respect to the mask M) at the first exposure and the projection magnification at the second exposure may be changed by the pressure adjusting unit 30. However, when the projection magnification is changed, the plurality of exposure areas on the plate P do not overlap each other.

Hereinafter, a detailed description will be given with reference to FIG. Figure 8
FIG. 6 is a plan view showing the relationship between the visual field area on the mask M and the exposure area on the plate P when the projection magnification of the projection optical systems 21 and 22 is a reduction magnification. In addition, in FIG. 8, the shape of the visual field area and the exposure area is a trapezoid
The case where the directions of the trapezoids of the adjacent visual field areas and exposure areas are similar to each other is shown.

In FIG. 8, the visual field region ML on the mask M is shown.
₁ and ML ₂ form a secondary image of the visual field area on the exposure areas PL ₁ and PL ₂ on the plate P by the projection optical systems 21 and 22 (not shown). At this time, the exposure areas PL ₁ , P
Since the magnification of L ₂ becomes smaller, the overlapping regions on the mask M do not overlap each other on the mask M.

Therefore, the plane-parallel plate 34 is swung in the projection optical system shown in FIG. 7 so as to move the exposure area PL ₂ in the Y direction. At this time, the swing angle of the plane-parallel plate 34 is determined so that the overlapping regions of the exposure regions PL ₁ and PL ₂ on the plate P overlap each other in the Y direction. It should be noted that the swing angle of the plane-parallel plate depends on each projection optical system 21.
˜25, the size of the visual field regions ML _{1 to} ML ₅ of each projection optical system 21 to 25, and the positions of the visual field regions ML _{1 to} ML ₅ with respect to the entire visual field of each projection optical system.

In the above example, the exposure area PL₂only
Is moving, but the exposure area PL ₁Move
Or exposure area PL₁, PL₂You can move both
Yes. Further, in the Z direction, the exposure area PL₁, PL₂of
If the position needs to be changed, the projection shown in FIG.
The plane-parallel plate 33 may be swung in the optical system. Figure
In the projection optical system shown in FIG.
The projection magnification is changed by adjusting the pressure.
However, a lens with a small refractive power is installed near the field stop 14.
And project by moving this lens in the optical axis direction
The magnification can be changed. Hereinafter, referring to FIG.
explain. In FIG. 9, the same coordinate system as in FIG. 1 is adopted.
It In addition, in order to simplify the description, the projections in FIGS.
Members having the same function as the shadow optical system are given the same reference numerals.
It is attached.

In FIG. 9, the reflecting surface 13a and the reflecting surface 15
Lenses 41 and 42 are provided so as to sandwich the field stop 14 in the optical path between them and a. These lenses 41,
42 is movable along the optical axis direction. Here, if the lenses 41 and 42 are moved along the optical axis direction, the combined focal length of the projection lens 20 and the lens 41, the combined focal length of the projection lens 20 and the lens 42, or both change. Thereby, the projection magnification of the entire projection optical system can be changed.

Here, the magnification of the field stop 14 (the plate P
When changing the magnification of the image of the field diaphragm 14 projected on top, the lenses 41 and 42 may be arranged in the optical path on the reflecting surface 15a side of the field diaphragm 14. If the magnification of the field stop 14 is not changed, the field stop 14
Above the lenses 41, 42 in the optical path closer to the reflecting surface 13a than
Should be placed.

When the projection optical system shown in FIGS. 7 and 9 is applied to the exposure apparatus shown in FIG. 3, input means for inputting information regarding the amount of expansion and contraction of the plate P is provided, and information regarding this amount of expansion and contraction is provided. Based on the plurality of projection optical systems 21 to 2
It is preferable to control the magnification for 5. At this time, it is preferable to store the relationship between the expansion / contraction amount and the pressure in the lens chamber (in the case of FIG. 7) or the movement amount of the lenses 41 and 42 (in the case of FIG. 9) in the form of a reference table. Here, when changing the magnification of the projection optical system in order to correct the expansion and contraction of the plate P, each projection optical system 21 to
Since it is necessary to correct the movement of the secondary image due to 25, the reference table includes the amount of expansion and contraction and the parallel plane plate 3.
It is preferable to store the relationship between the rocking angles of 3, 34.

When the plate P is partially expanded and contracted, the magnification of each projection optical system 21 to 25 and the magnification of each projection optical system 21 to 25 are reduced.
The movement amount of the next image may be controlled independently. Furthermore, when the projection optical system of FIG. 7 is applied to the exposure apparatus shown in FIG.
Each of the projection optical systems 21 to 25 can also be controlled by one pressure adjusting unit. At this time, each projection optical system 21 to
The lens chamber provided in 25 may be configured as one space, and the pressure in this space may be controlled by the pressure adjusting unit.

Further, in the projection optical system shown in FIGS. 1, 7 and 9, the reflecting surfaces 13a, 1 as the light flux transferring member.
5a may be configured by a dichroic mirror that reflects exposure light and transmits light having a wavelength different from the exposure light (for example, a wavelength longer than the exposure light). In this way, the reflective surface 13
When a and 15a are constituted by dichroic mirrors, the alignment optical system may be arranged on the reflection surface 13a or the reflection surface 15a or on the transmission side of both reflection surfaces 13a and 15a. At this time, the position of the mask M and the plate P is detected via the projection optical system, so-called TTL.
(Through the Lens) type alignment can be performed.

Next, a method of adjusting the projection optical system according to this embodiment will be briefly described. First, the aberration, magnification, and telecentricity of the projection lens 20 are adjusted to have predetermined values. Then, after adjusting the angle formed by the reflecting surface 10a and the reflecting surface 10b of the reflecting member 10 to be 90 °, the reflecting member 10 is fixed to the supporting member 11. The angle between the reflection surface 13a of the reflection member 13 and the reflection surface 15a of the reflection member 15 is adjusted to be 90 °, and then the support member 16 is fixed. After that, the lens barrel 12 of the projection lens 20 is fixed to the main body side of the exposure apparatus. Next, the support member 16 is positioned so that the reflection surfaces 13a and 15a form 45 ° with respect to the optical axis of the projection lens 20, and this support member is fixed to the exposure apparatus main body. Finally, with respect to the optical axis of the projection lens,
The support member 11 is positioned so that the reflection surfaces 10a and 10b form 45 °, and the support member 11 is fixed to the exposure apparatus main body side.

According to the adjusting method as described above, the reflecting surface 10
Since the error due to a, 10b, 13a, and 15a and the error due to the projection lens 20 can be obtained separately, it is easy to know which position should be adjusted, and the advantage of facilitating the adjustment of the entire projection optical system There is. In the projection optical system in each of the above-described embodiments, the reflecting member 10 as the visual field dividing member has the reflecting surfaces 10a and 10b, but the reflecting member 10 may be a prism. . Further, although the reflecting surfaces 10a and 10b are integrally provided on the reflecting member 10, the reflecting surfaces 10a and 10b may be provided separately in a member having the reflecting surface 10a and a member having the reflected component 10b. Furthermore, each reflection member 10, 13, 15
If it is rotatably provided around the YZ axis, there is an advantage that the entire projection optical system can be adjusted.

Further, in the exposure apparatus according to each of the above-described embodiments, the erecting normal image of the mask M can be obtained by one set of projection optical system, so that the distance between the mask M and the plate P is short. it can. As a result, there is an advantage that the rigidity of the carriage C that moves the mask M and the plate P integrally can be easily obtained.

[0065]

According to the present invention as described above, optical adjustments such as adjustment of optical axis deviation and adjustment of various aberrations can be easily performed.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a projection optical system of a first embodiment according to the present invention.

FIG. 2 is a diagram showing a configuration of an exposure apparatus of a first embodiment according to the present invention.

FIG. 3 is a diagram showing a configuration of an exposure apparatus of a second embodiment according to the present invention.

FIG. 4 is an enlarged view of a part of a projection optical system.

FIG. 5 is a diagram showing a visual field of a projection optical system.

FIG. 6 is a diagram showing a relationship between a field of view of a projection optical system and an opening of a field stop.

FIG. 7 is a diagram showing a modification of the projection optical system.

FIG. 8 is a diagram showing a relationship between a magnification and an overlap area.

FIG. 9 is a diagram showing a modification of the projection optical system.

FIG. 10 is a diagram showing a conventional exposure apparatus.

[Explanation of symbols]

10 ... Reflective member (visual field dividing member), 13, 15 ... Reflecting member (light flux transferring member), 20 ... Projection lens, 14 ... Field stop,

Claims (17)

(57) [Claims] 1. A projection optical system for forming an image of an object arranged on an object plane on a predetermined image plane, comprising: a projection optical system having an optical axis and two conjugate points; A visual field dividing member that is arranged on one of the two conjugate points and divides the visual field of the projection optical system; and a visual field dividing member that is arranged on the other conjugate point side of the projection optical system. and possess a light flux transfer member for transferring along the light through the projection optical system in the order in a direction transverse to the optical axis of said projection optical system, wherein a visual field dividing member and the light flux transfer member, or the object
From the field splitting member, the projection optical system, the light flux
Order of transfer member, projection optical system, and field dividing member
The projection optical device is characterized in that it is positioned so as to be guided to the image surface by passing through the projection optical device. 2. The projection optical apparatus according to claim 1, wherein the projection optical apparatus forms an intermediate image of the object, and a field stop is arranged at a position where the intermediate image is formed. 3. The projection optical apparatus according to claim 1, further comprising a magnification control unit for changing a projection magnification of the projection optical system. 4. The image moving means according to claim 1, further comprising image moving means for moving the position of the image of the object formed on the image plane along the in-plane direction of the image plane. The projection optical device according to claim 1. 5. The projection optical apparatus according to claim 1, wherein the projection optical system is housed in one lens barrel. 6. The projection optical apparatus according to claim 1, wherein the visual field dividing member is arranged on a side where the projection optical system is telecentric. 7. The projection optical apparatus according to claim 6, wherein the projection optical system is a both-side telecentric optical system. 8. An exposure apparatus for projecting a pattern of the first substrate onto the second substrate while moving the first substrate and the second substrate in the same direction, in which the first substrate is interposed. First reflecting surface that deflects the reflected light, an optical system that forms an intermediate image of the first substrate based on the light that has passed through the first reflecting surface, and the first reflecting surface that passes through the optical system. A light beam transfer member that transfers light from the optical system along a direction transverse to the optical axis of the optical system and guides the transferred light again to the optical system; and a light beam from the light beam transfer member that passes through the optical system. And a second reflecting surface that guides the light to the second substrate. 9. An exposure apparatus for projecting a pattern on the first substrate onto the second substrate while moving the first substrate and the second substrate in the same direction, An erecting erect image having first and second optical systems for forming on the second substrate, wherein the first and second optical systems include a projection optical system having an optical axis and two conjugate points; A first reflecting surface which is disposed on one conjugate point side of the projection optical system and which deflects light from the first substrate and guides it to the projection optical system; and the first reflecting surface via the projection optical system. A light flux transfer member for transporting light from the optical path along a direction transverse to the optical axis of the projection optical system and for guiding the transported light again to the projection optical system; and the light flux transport member via the projection optical system. And a second reflecting surface for deflecting light from the substrate and guiding it to the second substrate. Exposure equipment. 10. The exposure apparatus according to claim 8, wherein a field stop is arranged at a position where the intermediate image is formed. 11. The exposure apparatus according to claim 8, further comprising a magnification control unit for changing a projection magnification of the projection optical system. 12. An image moving means for moving the position of the image of the first substrate formed on the second substrate along the in-plane direction of the second substrate. The exposure apparatus according to claim 8. 13. The exposure apparatus according to claim 8, wherein an optical axis of the projection optical system is parallel to a moving direction of the first and second substrates. 14. The first substrate and the second substrate are moved in the same direction while the first substrate is patterned into the second substrate.
A plurality of projection optical systems that respectively form erect images of the first substrate on the second substrate, and a magnification adjustment for adjusting the magnification of the projection optical system. An exposure apparatus comprising: a unit, an input unit for inputting information regarding the amount of expansion and contraction of the substrate, and a control unit for performing magnification control for the plurality of projection optical systems based on the information. 15. The image moving means for moving the positions of the images of the first substrate formed on the second substrate along the in-plane direction of the second substrate, in the plurality of projection optical systems. 15. The exposure apparatus according to claim 14, wherein the control unit controls the amount of image movement by the image moving unit. 16. The magnification control for the plurality of projection optical systems is independently controlled.
The exposure apparatus according to item 5. 17. A step of detecting an optical axis of a projection optical system, and a step of positioning a visual field dividing member for spatially dividing two visual fields of the projection optical system with respect to the optical axis of the projection optical system. Positioning a light flux transfer member that transfers light that has passed through the visual field dividing member and the projection optical system in order with respect to the optical axis of the projection optical system, along a direction that intersects the optical axis of the projection optical system. And the visual field dividing member and the luminous flux transfer member are the objects.
From the field splitting member, the projection optical system, the light flux
Order of transfer member, projection optical system, and field dividing member
Positioned so as to be guided to the image plane by passing through
A method of adjusting a projection optical device, comprising: