JP6896404B2 - Exposure equipment and manufacturing method of articles - Google Patents

Description

The present invention relates to an exposure apparatus and a method for manufacturing an article.

In the lithography process of the manufacturing process of semiconductor devices, liquid crystal display devices, etc., the mask (reticle) is illuminated by the illumination optical system, and the mask pattern is transferred to the substrate coated with the photosensitive resist layer via the projection optical system. An exposure apparatus that projects an image is used.

The optical element of the projection optical system absorbs the exposure light to generate a temperature distribution in the optical element, so that the refractive index distribution and the surface shape of the optical element change. From the viewpoint of imaging characteristics, it is desirable to reduce aberrations such as focus difference or astigmatism (astigmatism) that may occur due to changes in the refractive index distribution and surface shape of the optical element.

Therefore, by supplying a temperature-controlled gas into the lens barrel that houses the projection optical system in accordance with the temperature rise of the entire inside of the projection optical system caused by the members in the projection optical system absorbing the exposure light. , An exposure apparatus that reduces changes in temperature distribution in a projection optical system is known.

Patent Document 1 describes the temperature distribution of the meniscus lens and the temperature distribution of the meniscus lens based on the information of the mask pattern used for exposure when gas is supplied between the meniscus lens installed near the pupil of the projection optical system and the convex mirror. It is disclosed to control the direction of gas flow so as to match.

Japanese Unexamined Patent Publication No. 2016-95412

In Patent Document 1, since gas is passed through a region where the temperature of the lens has risen to partially cool the lens, the temperature distribution of the entire lens is distributed when high-illuminance exposure light is incident on the projection optical system. Is not expected to be sufficiently uniform. In that case, in particular, it is difficult to keep both the astigmatism in the vertical and horizontal directions and the astigmatism in the oblique direction of the projection optical system within an allowable range.

Therefore, an object of the present invention is to provide an exposure apparatus for keeping a plurality of astigmatisms having different directions in the projection optical system within an allowable range even when the illuminance of the exposure light is high.

The exposure device as one aspect of the present invention that solves the above problems is an exposure device having a projection optical system that projects a mask pattern onto a substrate, and the projection optical system causes non-point aberration of the projection optical system. The exposure apparatus comprises a first optical element whose position or shape can be changed for adjustment, and a second optical element arranged on or near the pupil surface of the projection optical system. The supply unit has a control unit that controls the position or shape of the first optical element, and a supply unit that supplies gas to the second optical element in order to adjust the temperature distribution of the second optical element. is pre SL becomes opposite to each other the direction of increase or decrease of the astigmatism of the second direction different from the first astigmatism to the first direction of the direction caused by the temperature distribution of the second optical element, wherein the first direction astigmatism so falls within the allowable range, the position or shape of the second gas is supplied to the optical element, the first optical element to fit astigmatic before Symbol second direction within the allowable range of To control.

According to the present invention, even when the illuminance of the exposure light is high, a plurality of astigmatisms having different directions in the projection optical system can be contained within an allowable range.

It is a block diagram of an exposure apparatus. It is a figure which shows the temperature distribution of the meniscus lens 15'after exposure. It is a figure which shows the temperature distribution of the Zernike coefficient Z5, Z6 term. It is a figure which shows the structure around the convex mirror 15 and the meniscus lens 15'. It is sectional drawing of the lens barrel 100. It is a figure which shows the temperature distribution after gas supply. It is a flu chart which shows the correction method of astigmatism. It is a figure which shows the lens barrel, the air supply port and the exhaust port of Embodiment 2.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(First Embodiment)
The exposure apparatus of this embodiment will be described with reference to FIG. FIG. 1 is a schematic view of the exposure apparatus of the first embodiment. The exposure apparatus can be used, for example, in a lithography process in a manufacturing process of a flat panel such as a liquid crystal display device or an organic EL device. In particular, in the present embodiment, the exposure apparatus is a scanning projection exposure apparatus that transfers (exposes) an image of a pattern formed on a mask onto a plate (on a substrate) by a step-and-scan method. In FIG. 1, the Y-axis is taken in the scanning direction of the mask 9 and the plate 19 at the time of exposure in a plane perpendicular to the Z-axis in the vertical direction, and the X-axis is taken in the non-scanning direction orthogonal to the Y-axis. The plate 19 is, for example, a substrate to be treated, which is made of a glass material and has a surface coated with a photosensitive agent (resist).

The exposure apparatus of this embodiment includes an illumination system IL, a projection optical system PO, an original plate drive mechanism that scans a mask (original plate) 9 arranged on an object surface OP of the projection optical system PO, and an image of the projection optical system PO. A substrate drive mechanism for scanning the substrate 19 arranged on the surface IP and a control unit C are provided.

The illumination system IL may include, for example, a light source LS, a first condenser lens 3, a fly-eye lens 4, a second condenser lens 5, a slit defining member 6, an imaging optical system 7, and a plane mirror 8. The light source LS may include, for example, a mercury lamp 1 and an elliptical mirror 2. The slit defining member 6 defines the illumination range of the original plate 9 (that is, the cross-sectional shape of the slit-shaped light that illuminates the original plate 9). The imaging optical system 7 is arranged so as to form a slit defined by the slit defining member 6 on the object surface. The plane mirror 8 bends an optical path in the illumination system IL. The projection optical system PO projects the pattern of the original plate 9 arranged on the object surface OP onto the substrate 19 arranged on the image plane IP, whereby the substrate 19 is exposed. The projection optical system PO can be configured as any of the same magnification imaging optical system, the magnifying imaging optical system, and the reduced imaging optical system. However, the projection optical system PO is preferably configured as a 1x magnification imaging optical system, and the main rays are parallel on the object surface side and the image surface side, that is, they have both telecentricity on both the object surface and the image surface. There is.

The projection optical system PO is a first plane mirror 13, a first concave mirror 14, a convex mirror 15, a second concave mirror 16, and a second plane mirror as mirrors arranged in order from the object surface side in the optical path from the object surface OP to the image surface IP. Has 17. The optical path between the object OP and the first plane mirror 13 and the optical path between the second plane mirror 17 and the image plane IP are parallel. The plane including the mirror surface of the first plane mirror 13 and the plane including the mirror surface of the second plane mirror 17 form an angle of 90 degrees with each other. The first plane mirror 13 and the second plane mirror 17 may be integrally formed. The first concave mirror 14 and the second concave mirror 16 may be integrally configured. The projection optical system PO includes cylindrical lenses 21 and 22 arranged in an optical path between the object surface OP and the first plane mirror 13, and a plano-concave lens (or plano-convex lens) 12'. The projection optical system PO also includes cylindrical lenses 23 and 24 arranged in an optical path between the second plane mirror 17 and the image plane. In the projection optical system PO, a meniscus lens (aspherical lens) 15'is arranged in front of the convex mirror 15 in order to correct the axial chromatic aberration caused by these lenses. The reflective surface of the convex mirror 15 corresponds to the pupil surface of the projection optical system. The convex mirror 15 is arranged on the pupil surface of the projection optical system, and the meniscus lens 15'is arranged near the pupil surface of the projection optical system. These optical elements have a non-uniform temperature distribution during exposure.

The cylindrical lenses 23 and 24 adjust the projection magnification of the projection optical system in the second direction (y direction) orthogonal to the first direction (z direction) along the optical path between the object surface OP and the first plane mirror 13. It constitutes one optical system. The cylindrical lenses 21 and 22 constitute a second optical system that adjusts the projection magnification of the projection optical system in the third direction (x direction) orthogonal to the first direction and the second direction. The plano-concave lens 12'consists of a third optical system that adjusts the projection magnification of the projection optical system in the first direction and the second direction.

The cylindrical lens 21 is a concave cylindrical surface having a flat upper surface and a curvature on the lower surface in the x direction, and has an air spacing of about 5 to 20 mm to the upper surface of the cylindrical lens 22. The cylindrical lens 22 has a convex cylindrical surface having a curvature in the x direction on the upper surface, a convex spherical surface on the lower surface, a concave spherical surface on the upper surface, and an air spacing of about 5 to 20 mm to the upper surface of the plano-concave lens 12'having a flat surface on the lower surface. have. The cylindrical lens 21 or the cylindrical lens 22 is configured to be movable (driveable) in the z direction by an actuator 31 (driving unit). With respect to the cylindrical lens 22, the magnification in the x direction is corrected by driving the cylindrical lens 21 in the z direction. Further, by driving the plano-concave lens 12'in the z direction by the actuator 31, the magnification is corrected isotropically in the x direction and the y direction.

The control unit C is configured by, for example, a computer or the like, is connected to each component of the exposure apparatus via a line, and can control the operation and adjustment of each component according to a program or the like. The control unit C can control the actuator (driving unit) that drives the cylindrical lens and the plano-concave lens to control the position and shape of the lens, or both.

The cylindrical lens 23 has a flat surface on the upper surface and a concave cylindrical surface having a curvature in the scanning direction on the lower surface, and has an air spacing of about 5 to 20 mm to the upper surface of the cylindrical lens 24. The cylindrical lens 24 has a convex cylindrical surface having a curvature in the scanning direction on the upper surface and a flat surface on the lower surface. The position of the cylindrical lens 23 or the cylindrical lens 24 can be changed (moved) in the z direction by the actuator 32. The magnification in the y direction can be corrected by moving the cylindrical lens 23 in the z direction by the actuator 32. The thickness and spacing of each of the cylindrical lenses 21, 22, 23, and 24 are arbitrary as long as they do not deform by their own weight when held in space, and the space holding mechanism and vertical drive mechanism can be configured. On the cylindrical surface, in the case of synthetic quartz having a refractive index of around 1.475, if the radius of curvature is set to about 47,000 mm, the magnification changes by about 10 ppm with a movement of 1 mm. However, each cylindrical surface and spherical surface need to be slightly changed so that the size of the image passed through the three lenses placed at the reference height position is exactly the same as when the three lenses were not present. The concave and convex surfaces of the cylindrical surface and the concave and convex surfaces of the spherical surface may be opposite to each other. The magnification correction means is not limited to the cylindrical lens, and a mechanism for bending the parallel plate plate or a mechanism for adjusting the rotation position of the lens may be used so that the position and shape of the parallel plate plate or both can be changed.

The projection magnification can be adjusted by moving the cylindrical lens as described above, but astigmatism can also be adjusted. For example, when adjusting the projection magnification in the y direction, when the cylindrical lens 23 having a flat surface on the upper surface and a concave cylindrical surface having a curvature in the scanning direction on the lower surface is moved in the z direction, a refractive power in a direction orthogonal to the scanning direction is obtained. Does not change, but a negative refractive power is generated in the scanning direction. Therefore, a line image (V line) in the scanning direction is formed at a position (lower side) farther from the projection optical system than the line image (H line) in the direction perpendicular to the scanning direction. .. That is, the first optical system has the sensitivity of the projection magnification in the y direction and the sensitivity of astigmatism generated in the vertical and horizontal directions (x, y directions). The second optical system has the sensitivity of the projection magnification in the x direction and the sensitivity of astigmatism generated in the vertical and horizontal directions. The third optical system has sensitivity of projection magnification in the x-direction and y-direction, and is not sensitive to astigmatism generated in the vertical and horizontal directions. Therefore, by driving these lenses, astigmatism in the vertical and horizontal directions can be generated without changing the projection magnifications in the two directions orthogonal to each other. As an example, when the cylindrical lens 21 is driven by +1 mm in the Z direction, the cylindrical lens 23 is driven by +2 mm in the Z direction, and the plano-concave lens 12'is driven by +1 mm in the Z direction, the projection magnifications in the x and y directions are not changed and the astigmatism in the vertical and horizontal directions is not changed. It is possible to generate astigmatism of 3 um. According to the mechanism described above, the amount of correction for astigmatism is proportional to the amount of driving of the lens. Therefore, if a space for avoiding interference during driving is provided between the lenses, the amount of driving the lens can be increased and the amount of astigmatism correction can be increased.

Therefore, the control unit C controls the position of any one of the cylindrical lenses 21, 22, 23, 24 and the plano-concave lens 12'(first optical element). As a result, the projection magnification in the x and y directions can be set as a predetermined target value, and the astigmatism in the vertical and horizontal directions can be within an allowable range. When a parallel plate is used instead of the cylindrical lens, the projection magnification and astigmatism can be adjusted by controlling the shape of the parallel plate.

Next, the temperature distribution of the meniscus lens 15'will be described. FIG. 2 shows the temperature distribution of the meniscus lens 15'when a certain mask pattern is exposed on a substrate. The temperature distribution of the convex mirror 15 is almost the same as the temperature distribution of the meniscus lens 15'. There are high temperature portions in the peripheral regions on both sides in the B-axis direction across the center of the meniscus lens 15', and low temperature portions in the peripheral regions on both sides in the C-axis direction across the center of the meniscus lens 15'. The Z5 and Z6 terms when the temperature distribution of the meniscus lens 15'is decomposed by the Zernike function are shown in FIG.

The left figure of FIG. 3 shows the temperature distribution of the Z5 term shape of the Zernike coefficient, and the right figure of FIG. 3 shows the temperature distribution of the Z6 term shape of the Zernike coefficient. In the Zernike coefficient Z5 shape temperature distribution, there are high temperature parts near both ends in the X-axis direction across the center of the meniscus lens 15', and near both ends in the Z-axis direction across the center of the meniscus lens 15'. There is a low temperature part. In the Z6 shape temperature distribution of the Zernike coefficient, there are high temperature parts near both ends in the B-axis direction across the center of the meniscus lens 15', and near both ends in the C-axis direction across the center of the meniscus lens 15'. There is a low temperature part. The B-axis and C-axis are axes inclined at an angle of 45 degrees from the X-axis or the Z-axis, and are perpendicular to each other.

When the temperature distribution of the Z5 term occurs in the meniscus lens 15', the refractive index distribution of the Z5 term is obtained, and the wavefront aberration of the Z5 term occurs. When the wavefront aberration of the Z5 term occurs, the focal position of the horizontal line (H line) and the focal position of the vertical line (V line) of the mask pattern deviate from each other. Therefore, astigmatism in the vertical and horizontal directions, which is the difference between the focal position of the H line and the focal position of the V line, occurs. Further, when the temperature distribution of the Z6 term occurs in the meniscus lens 15', the refractive index distribution of the Z6 term is obtained, and the wavefront aberration of the Z6 term occurs. When the wavefront aberration of the Z6 term occurs, the focal position of the upper right diagonal line (S line) tilted 45 degrees with respect to the H line of the mask pattern and the focal point of the upper left diagonal line (T line) tilted 135 deg with respect to the H line. The position shifts. Therefore, astigmatism in the oblique direction, which is the difference between the focal position of the S line and the focal position of the T line, occurs. Here, the astigmatism in the oblique direction is referred to as astigmatism in the first direction, and the astigmatism in the longitudinal and horizontal directions is referred to as astigmatism in the second direction. Although the vertical and horizontal directions and the diagonal directions are different by 45 degrees, the angle difference between the first direction and the second direction is not limited to 45 degrees and may be different directions. Further, the astigmatism in the oblique direction is not limited to the Z6 term and may include the Z13 term and the like, and the astigmatism in the vertical and horizontal directions may include not only the Z5 term but also the Z12 term and the like.

Next, the temperature adjustment of the convex mirror 15 or the meniscus lens 15'(second optical element) will be described. FIG. 4 shows the peripheral configuration of the convex mirror 15 and the meniscus lens 15'. The figure on the right side of FIG. 4 is a view seen from the Y direction, and the figure on the left side of FIG. 4 shows a cross-sectional view in DD'. The alternate long and short dash line in the Y-axis direction indicates the optical axis. The convex mirror 15 and the meniscus lens 15'are held in the lens barrel 100 (holding portion). As shown in FIG. 4, a closed space 102 is formed between the convex mirror 15 and the meniscus lens 15'. The lens barrel 100 is provided with a plurality of holes 103 and 104 extending in the Z direction. The hole 103 is a gas air supply port, and the hole 104 is a gas exhaust port. FIG. 5 shows a cross-sectional view of the lens barrel 100 passing through AA'. In the lens barrel 100, a plurality of air supply ports 103A to G are provided as through holes. Each of the plurality of air supply ports 103A to G extends in the same Z direction. Further, in the lens barrel 100, exhaust ports 104A to G are provided as through holes on the side opposite to the air supply ports 103A to G with respect to the optical axis of the meniscus lens 15'at the intersection of the alternate long and short dash lines. .. Further, the air supply port and the exhaust port extend in the lens barrel 100 in the direction from the air supply port to the exhaust port (Z direction). For example, the air supply port 103A extends in a direction (Z direction) parallel to the line passing through the optical axis of the air supply port 103D and the meniscus lens 15'. On the lower side of the lens barrel 100, a plurality of air supply ports 103A to G are provided at substantially equal intervals in the X-axis direction. The plurality of exhaust ports 104A to G are provided on the upper side of the lens barrel 100 at substantially equal intervals in the X-axis direction. The plurality of air supply ports 103A to G and exhaust ports 104A to G are provided up to positions that cover the entire diameter of the convex mirror 15 and the meniscus lens 15'in the X direction. An air supply path 36 for supplying gas is connected to the plurality of 103A to G, and an exhaust path 37 for exhausting gas is connected to the plurality of exhaust ports 104A to G. As the gas, air, nitrogen, or the like is preferable, and air does not need to replace the gas inside the closed space, and there is no waiting time until the replacement is completed, so that the exposure apparatus can be used immediately. Since nitrogen is an inert gas, it is excellent in that it does not fog the mirror and lens.

The air supply path 36 and the exhaust path 37 are connected to a gas supply unit 35 that adjusts the flow rate and temperature of the gas, and the gas supply and exhaust are adjusted by the gas supply unit 35. The gas supply unit 35 regulates the temperature of the gas to a constant temperature. The air supply path 36 and the exhaust path 37 may be one system or a plurality of systems, one system may be provided in one hole, or one system may be branched and connected to each hole. If there are multiple systems, the gas flow rate and temperature can be adjusted independently for each system. Further, the operation of the gas supply unit 35 is controlled by the control unit C.

Arrow 107 indicates the flow of gas before it flows into the air supply ports 103A to G. The plurality of arrows correspond to each of the plurality of air supply ports 103A to G. The gas temperature-controlled by the gas supply unit 35 is supplied from the plurality of air supply ports 103A to G. Arrow 108 indicates the flow of gas flowing out from the exhaust ports 104A to G, and the gas is exhausted from the exhaust ports 104A to G. By doing so, a gas flow 109 is created in the closed space 102 between the convex mirror 15 and the meniscus lens 15, and the temperature in the closed space 102 is adjusted. The plurality of air supply ports 103A to G and exhaust ports 104A to G are provided up to positions that cover the entire diameter of the convex mirror 15'and the meniscus lens 15'in the X direction. That is, the air supply ports 103A and 103G and the exhaust ports 104A and 104G are arranged near the outer periphery of the convex mirror 15'and the meniscus lens 15'. Therefore, the temperature-controlled gas can be sprayed over the entire surface of the convex mirror 15 and the meniscus lens 15'. Further, since the plurality of air supply ports 103A to G and the exhaust ports 104A to G extend in the Z direction, the directions are aligned. Furthermore, the flow rate of the supply air and the flow rate of the exhaust gas match. As a result, the gas flow paths are aligned in the Z direction (one direction), and the gas flow does not stagnate in the closed space 102, so that the gas flows in the laminar flow 109. That is, gas is flowed from each of the plurality of air supply ports along the same direction to the surface of the convex mirror 15'and the meniscus lens 15'.

In this way, the temperature-controlled gas is supplied to the closed space 102 between the convex mirror 15 and the meniscus lens 15', and the gas is allowed to flow on the surfaces of the convex mirror 15 and the meniscus lens 15', so that the convex mirror 15 and the meniscus lens 15' The temperature distribution of the lens can be adjusted. After continuing to supply the temperature-controlled gas to the closed space 102 between the convex mirror 15 and the meniscus lens 15', the temperature distribution of the convex mirror 15 and the meniscus lens 15' contacting the closed space 102 is the Z axis as shown in FIG. The temperature distribution is symmetrical with respect to the temperature distribution. FIG. 6 shows a diagram of the approximate temperature distribution of the convex mirror 15 and the meniscus lens 15'. The region 1 has the lowest temperature, the region 2 has a higher temperature than the region 1, and the region 3 has the highest temperature. The convex mirror 15 and the meniscus lens 15'have heat due to exposure, and the temperature rises as the distance from the gas air supply port increases. In the region near the air supply port, it can be seen that the temperature is lowered by the low-temperature gas. As the temperature distribution approaches symmetrical with respect to the Z axis, the wavefront aberration of the Z5 term increases and the wavefront aberration of the Z6 term decreases. That is, the astigmatism in the vertical and horizontal directions is larger and the astigmatism in the diagonal direction is smaller than when no gas is supplied, and the directions of increase and decrease of the astigmatism in the vertical and horizontal directions and the astigmatism in the diagonal direction are opposite to each other. become. When the substrate is exposed with high illuminance, the temperature unevenness of the lens of the projection optical system becomes large, and the aberration becomes large. However, even when the substrate is exposed with high illuminance, astigmatism in the oblique direction can be kept within an allowable range by controlling the gas supply by the gas supply unit 35 as described above. As a specific example, as a result of continuing to supply the temperature-controlled gas to the space 102 between the convex mirror 15 and the meniscus lens 15'by the gas supply unit 35, the amount of reduction in astigmatism in the oblique direction is 2.5 μm. Met.

In this way, instead of making the temperature distribution of the convex mirror 15 and the meniscus lens 15'overall uniform, the astigmatism in the oblique direction is reduced and the astigmatism in the longitudinal and horizontal directions is allowed to be increased. In addition, a gas flow is created and the temperature distribution is adjusted. Therefore, the astigmatism in the vertical and horizontal directions is not within the permissible range, but rather may be larger than before the gas is supplied.

Next, a method for correcting astigmatism in the vertical and horizontal directions will be described. FIG. 7 shows a flowchart of the correction method. First, the control unit C controls the gas supply unit 35 to start supplying the temperature-controlled gas to the closed space 102 between the convex mirror 15 and the meniscus lens 15'as described above, and then starts supplying the temperature-controlled gas to the convex mirror 15 and the meniscus lens 15. The temperature distribution of 15'is adjusted (S301). While the gas is continuously supplied, the control unit C controls each part of the exposure apparatus so that the projection optical system PO projects the pattern of the mask 9 onto the substrate 19 and exposes the substrate 19. For example, when the substrate is exposed with high illuminance, the temperature of the lens or the like of the projection optical system becomes high, and the aberration may not be within the permissible range. When the gas is supplied in S301, the astigmatism in the oblique direction of the projection optical system is within the permissible range, but the astigmatism in the vertical and horizontal directions is not within the permissible range. Therefore, astigmatism in the vertical and horizontal directions is measured every time the exposed substrate 19 is replaced or every lot (S302). The measurement of astigmatism can be performed using, for example, a focus sensor 40 (measurement unit) arranged on a substrate stage for moving the substrate. Then, the cylindrical lenses 21, 22, 23, 24 and the plano-concave lens 12 for reducing the astigmatism in the vertical and horizontal directions within an allowable range based on the measurement result, that is, the measured amount of astigmatism in the vertical and horizontal directions. 'Calculate the amount of movement of any of the lenses (S303). Then, the lens is driven based on the calculated movement amount of the lens (S304). Then, both the astigmatism in the vertical and horizontal directions and the astigmatism in the oblique direction can be kept within the permissible range. Then, the next substrate is exposed using the projection optical system in which the astigmatism is within the permissible range (S305).

In this way, the gas is supplied so that the increase and decrease of the astigmatism in the first direction caused by the temperature distribution of the second optical element at the time of exposure and the astigmatism in the second direction different from the first direction are opposite to each other. The unit flows gas on the surface of the second optical element to adjust the temperature of the second optical element. Further, the gas supply unit adjusts the temperature of the second optical element by flowing a gas on the surface of the second optical element so that the astigmatism in the first direction is within the permissible range. Further, the position or shape of the first optical element is controlled so that the astigmatism in the second direction at the time of exposure is within the permissible range. As a result, even when the illuminance is high, the astigmatism in the first direction and the astigmatism in the second direction of the projection optical system can be kept within an allowable range.

(Second Embodiment)
Next, the exposure apparatus of the third embodiment will be described. The gas supply port and exhaust port from the gas supply unit 35 are not limited to the holes made in the lens barrel 100. In this embodiment, a punching plate provided with a large number of holes is attached to the side surface of the lens barrel 100. If the hole is made in the lens barrel 100, the lens barrel 100 can be easily manufactured. On the other hand, the punching plate can effectively reduce the cooling unevenness of the temperature control. FIG. 8 shows a cross-sectional view of the lens barrel 100 to which the punching plate is attached. A large opening having a length similar to the diameter of the convex mirror 15 and the meniscus lens 15'was provided on the lower side of the lens barrel 100 in the z-axis direction, and a large number of holes 204 were provided so as to cover the openings. A punching plate 201 is attached. Further, a large opening is provided on the upper side of the lens barrel 100 in the z-axis direction, and a punching plate 200 provided with a large number of holes 203 is attached so as to cover the opening. Gas is supplied to the closed space 102 between the convex mirror 15 and the meniscus lens 15'through the hole of the punching plate 201, and the gas is exhausted from the closed space 102 through the hole of the punching plate 200. In this way, by supplying gas from an opening having a length similar to the diameter of the convex mirror 15 or the meniscus lens 15'and exhausting the gas, the gas flows over the entire surface of the convex mirror 15 or the meniscus lens 15'. be able to. Therefore, the convex mirror 15 and the meniscus lens 15'have a temperature distribution as shown in FIG. 6, and astigmatism in the vertical and horizontal directions becomes larger and astigmatism in the oblique direction becomes smaller than when no gas is supplied. Therefore, even when the substrate is exposed with high illuminance, astigmatism in the oblique direction can be kept within an allowable range.

(Third Embodiment)
Next, the exposure apparatus of the third embodiment will be described. In the first embodiment, astigmatism in the vertical and horizontal directions was measured. In the present embodiment, the amount of change in astigmatism in the vertical and horizontal directions is calculated from the mask pattern information and the integrated exposure amount.

First, the coefficient of change in astigmatism in the vertical and horizontal directions (exposure history coefficient) with respect to the integrated exposure amount of the substrate is obtained by an experiment. Specifically, an integrated exposure meter that detects the light branched from the optical path of the illumination optical system IL is used. The correspondence between the illuminance of the light branched from the optical path of the illumination optical system IL and the illuminance of the light on the substrate is required in advance. The illuminance measured by the integrated exposure meter is accumulated during the continuous exposure period, and the integrated exposure amount on the substrate is indirectly obtained based on the correspondence. Further, when continuously exposed, the focus sensor 40 measures the change in astigmatism in the vertical and horizontal directions while measuring the integrated exposure amount. Then, the control unit C obtains a coefficient of change in astigmatism in the vertical and horizontal directions with respect to the integrated exposure amount of the substrate by using these measurement data. This exposure history coefficient is stored in the memory of the control unit C. Then, when actually exposing the substrate, instead of the measurement in S302 of FIG. 7, the control unit C uses the obtained exposure history coefficient, mask pattern information, and integrated exposure when actually exposing the substrate. The amount is used to calculate the amount of change in astigmatism in the vertical and horizontal directions. Then, the control unit C calculates the driving amount of the cylindrical lens or the like required to correct the astigmatism in the vertical and horizontal directions. Then, the control unit C controls the drive unit that drives the lens based on the calculated drive amount.

According to the method of the present embodiment, it is possible to predict a change in astigmatism in the vertical and horizontal directions during a period in which the focus sensor cannot measure aberrations, such as while moving the substrate to expose the substrate. Aberrations can be corrected by driving the lens. Therefore, it is possible to correct changes in astigmatism in the vertical and horizontal directions during processing on one substrate or during one-shot exposure.

(Manufacturing method of goods)
Next, a method of manufacturing an article (semiconductor IC element, liquid crystal display element, color filter, MEMS, etc.) using the above-mentioned exposure apparatus will be described. Articles include a step of exposing a substrate (wafer, glass substrate, etc.) coated with a photosensitizer using the above-mentioned exposure apparatus, a step of developing the substrate (photosensitizer), and the developed substrate. Manufactured by processing in a well-known processing process. Other well-known steps include etching, resist stripping, dicing, bonding, packaging and the like. According to this manufacturing method, it is possible to manufacture a high-quality article as compared with the conventional one.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and modifications can be made within the scope of the gist thereof. Although the description has been made on the premise that the control unit C in the exposure apparatus performs calculations and controls, a control unit outside the exposure apparatus may be used as the control unit. Further, although an example in which one meniscus lens 15'is arranged in the vicinity of the convex mirror 15 has been described, a plurality of lenses may be arranged. In this case, gas is supplied to the space between the plurality of lenses to adjust the temperature distribution of the lenses as described above. Further, when the required exposure accuracy is low, it is not necessary to arrange the meniscus lens. In this case, the gas supply unit causes the gas to flow on the surface of the convex mirror to adjust the temperature distribution of the convex mirror. Moreover, although the reflection type projection optical system has been described, it can also be applied to the refraction type projection optical system. In the case of a refraction type projection optical system, a temperature-controlled gas is passed through a lens arranged near the pupil surface to generate astigmatism in one direction, and astigmatism in the other direction is caused by another optical element. to correct.

Claims (32)

An exposure apparatus having a projection optical system that projects a mask pattern onto a substrate.
The projection optical system is
A first optical element whose position or shape can be changed to adjust the astigmatism of the projection optical system,
It has a pupil surface of the projection optical system or a second optical element arranged in the vicinity of the pupil surface, and has.
The exposure apparatus is
A control unit that controls the position or shape of the first optical element,
It has a supply unit that supplies gas to the second optical element in order to adjust the temperature distribution of the second optical element.
In the supply unit, the directions of increase and decrease of the astigmatism in the first direction caused by the temperature distribution of the second optical element and the astigmatism in the second direction different from the first direction are opposite to each other, and the first A gas is supplied to the second optical element so that the astigmatism in one direction is within the permissible range.
The control unit is an exposure apparatus characterized in that the position or shape of the first optical element is controlled so that the astigmatism in the second direction falls within an allowable range. The projection optical system has a holding portion for holding the second optical element.
The exposure according to claim 1, wherein the supply unit causes gas to flow from each of the plurality of air supply ports provided in the holding unit to the surface of the second optical element along the same direction as each other. apparatus. The exposure apparatus according to claim 2, wherein in the holding portion, each of the plurality of air supply ports extends in the same direction. In the holding part
A plurality of exhaust ports are provided on the side opposite to the air supply port with respect to the optical axis of the second optical element.
The exposure apparatus according to claim 2 or 3, wherein the plurality of air supply ports and the plurality of exhaust ports extend in the same direction. By controlling the position or shape of the first optical element by the control unit, it is possible to adjust the projection magnification in the direction perpendicular to each other of the projection optical system, and to adjust the astigmatism in the second direction. The exposure apparatus according to any one of claims 1 to 4, wherein the exposure apparatus can be used. It has a measuring unit for measuring astigmatism in the second direction of the projection optical system.
Any of claims 1 to 5, wherein the position or shape of the first optical element is controlled so that the astigmatism in the second direction falls within an allowable range based on the measurement result by the measuring unit. The exposure apparatus according to item 1. The control unit calculates and calculates the driving amount of the first optical element required to keep the astigmatism in the second direction within an allowable range based on the exposure history of the substrate by the projection optical system. The exposure apparatus according to any one of claims 1 to 5, wherein the driving of the first optical element is controlled based on the driven amount. The exposure apparatus according to any one of claims 1 to 7, wherein the second direction is a direction different from the first direction by 45 degrees. The projection optical system includes a concave mirror, a convex mirror, and a lens arranged between the concave mirror and the convex mirror and held so as to form a space between the concave mirror and the convex mirror.
The exposure apparatus according to any one of claims 1 to 8, wherein the second optical element is a convex mirror or a lens. The exposure apparatus according to claim 9, wherein the supply unit supplies gas to the space between the convex mirror and the lens. An exposure apparatus having a projection optical system that projects a mask pattern onto a substrate.
The projection optical system is
A first optical element whose position or shape can be changed to adjust the astigmatism of the projection optical system,
It has a pupil surface of the projection optical system or a second optical element arranged in the vicinity of the pupil surface, and has.
The exposure apparatus is
A control unit that controls the position or shape of the first optical element,
It has a supply unit that supplies gas to the second optical element in order to adjust the temperature distribution of the second optical element.
In the supply unit, the astigmatism in the first direction caused by the temperature distribution of the second optical element is within an allowable range, and the astigmatism in the second direction intersecting the first direction is increased. Supply gas to the second optical element,
The control unit is an exposure apparatus characterized in that the position or shape of the first optical element is controlled so that the astigmatism in the second direction falls within an allowable range. By controlling the position or shape of the first optical element by the control unit, it is possible to adjust the projection magnification in the direction perpendicular to each other of the projection optical system, and to adjust the astigmatism in the second direction. The exposure apparatus according to claim 11, wherein the exposure apparatus can be used. It has a measuring unit for measuring astigmatism in the second direction of the projection optical system.
The 11th or 12th claim, wherein the position or shape of the first optical element is controlled so that the astigmatism in the second direction falls within an allowable range based on the measurement result by the measuring unit. Exposure device. The control unit calculates and calculates the driving amount of the first optical element required to keep the astigmatism in the second direction within an allowable range based on the exposure history of the substrate by the projection optical system. The exposure apparatus according to any one of claims 11 to 13, wherein the driving of the first optical element is controlled based on the driven amount. The exposure apparatus according to any one of claims 11 to 14, wherein the second direction is a direction different from the first direction by 45 degrees. The projection optical system includes a concave mirror, a convex mirror, and a lens arranged between the concave mirror and the convex mirror and held so as to form a space between the concave mirror and the convex mirror.
The exposure apparatus according to any one of claims 11 to 15, wherein the second optical element is a convex mirror or a lens. The exposure apparatus according to claim 16, wherein the supply unit supplies gas to a space between the convex mirror and the lens. An exposure apparatus having a projection optical system that projects a mask pattern onto a substrate.
The projection optical system is
A first optical element that can be driven to adjust the astigmatism of the projection optical system,
It has a second optical element that produces a non-uniform temperature distribution during exposure.
The exposure apparatus is
A drive unit that drives the first optical element and
It has a supply unit that supplies gas to the second optical element in order to adjust the temperature distribution of the second optical element.
In the supply unit, the directions of increase and decrease of the astigmatism in the first direction caused by the temperature distribution of the second optical element and the astigmatism in the second direction different from the first direction are opposite to each other, and the first A gas is supplied to the second optical element so that the astigmatism in one direction is within the permissible range.
The driving unit is an exposure apparatus characterized in that the first optical element is driven so that astigmatism in the second direction is within an allowable range. By driving the first optical element by the driving unit, it is possible to adjust the projection magnification of the projection optical system in the direction perpendicular to each other, and to adjust the astigmatism in the second direction. The exposure apparatus according to claim 18, wherein the exposure apparatus is characterized by the above. It has a measuring unit for measuring astigmatism in the second direction of the projection optical system.
The exposure apparatus according to claim 18 or 19, wherein the first optical element is driven so that the astigmatism in the second direction is within an allowable range based on the measurement result by the measuring unit. .. Based on the exposure history of the substrate by the projection optical system, the driving amount of the first optical element required to keep the astigmatism in the second direction within the allowable range is calculated, and the driving amount is calculated. The exposure apparatus according to any one of claims 18 to 20, wherein the driving unit drives the first optical element. The exposure apparatus according to any one of claims 18 to 21, wherein the second direction is a direction different from the first direction by 45 degrees. The projection optical system includes a concave mirror, a convex mirror, and a lens arranged between the concave mirror and the convex mirror and held so as to form a space between the concave mirror and the convex mirror.
The exposure apparatus according to any one of claims 18 to 22, wherein the second optical element is a convex mirror or a lens. The exposure apparatus according to claim 23, wherein the supply unit supplies gas to the space between the convex mirror and the lens. An exposure apparatus having a projection optical system that projects a mask pattern onto a substrate.
The projection optical system is
A first optical element that can be driven to adjust the astigmatism of the projection optical system,
It has a second optical element that produces a non-uniform temperature distribution during exposure.
The exposure apparatus is
A drive unit that drives the first optical element and
It has a supply unit that supplies gas to the second optical element in order to adjust the temperature distribution of the second optical element.
In the supply unit, the astigmatism in the first direction caused by the temperature distribution of the second optical element is within an allowable range, and the astigmatism in the second direction intersecting the first direction is increased. Supply gas to the second optical element,
The driving unit is an exposure apparatus characterized in that the first optical element is driven so that astigmatism in the second direction is within an allowable range. By driving the first optical element by the driving unit, it is possible to adjust the projection magnification of the projection optical system in the direction perpendicular to each other, and to adjust the astigmatism in the second direction. The exposure apparatus according to claim 25. Measuring unit for measuring the astigmatism of the second direction before Symbol projection optical system has a
The exposure apparatus according to claim 25 or 26, wherein the first optical element is driven so that the astigmatism in the second direction falls within an allowable range based on the measurement result by the measuring unit. .. Based on the exposure history of the substrate by the projection optical system, the driving amount of the first optical element required to keep the astigmatism in the second direction within the allowable range is calculated, and the driving amount is calculated. The exposure apparatus according to any one of claims 25 to 27, wherein the driving unit drives the first optical element. The exposure apparatus according to any one of claims 25 to 28, wherein the second direction is a direction different from the first direction by 45 degrees. The projection optical system includes a concave mirror, a convex mirror, and a lens arranged between the concave mirror and the convex mirror and held so as to form a space between the concave mirror and the convex mirror.
The exposure apparatus according to any one of claims 25 to 29, wherein the second optical element is a convex mirror or a lens. The exposure apparatus according to claim 30, wherein the supply unit supplies gas to a space between the convex mirror and the lens. It is a manufacturing method for manufacturing articles.
A step of exposing a substrate using the exposure apparatus according to any one of claims 1 to 31.
The process of developing the exposed substrate and
A manufacturing method comprising a step of manufacturing the article by processing the developed substrate.

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