Illumination optical system, exposure apparatus, and method for manufacturing article

Abstract

To provide a technique advantageous for changing the illuminance of a substrate in accordance with the speed of the substrate during scanning exposure.SOLUTION: An exposure apparatus performs scanning exposure of a substrate and includes: an illumination optical system configured to illuminate an original using light from a light source; a projection optical system that projects an image of a pattern of the original to the substrate; and a control unit that changes an intensity of the light exiting from the illumination optical system in accordance with a speed of the substrate in the scanning exposure. The illumination optical system comprises a first light-transmissive member and a second light-transmissive member that are arranged on an optical path of the light. In the scanning exposure, the control unit drives one of the first light-transmissive member and the second light-transmissive member such that an incident angle of the light to the one increases within a first angle range, and drives the other of the first light-transmissive member and the second light-transmissive member such that the incident angle of light to the other decreases within a second angle range, thereby changing the intensity of the light. Each of the first angle range and the second angle range includes a Brewster's angle.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to illumination optical system, The present invention relates to an exposure apparatus and a method for manufacturing an article. [Background technology]

[0002] As a lithography apparatus used in the manufacturing process of semiconductor devices and the like, there is known an exposure apparatus (so-called scanning exposure apparatus) that transfers a pattern of an original onto a substrate by exposing the substrate while scanning the original and the substrate relative to a projection optical system. In such an exposure apparatus, it is common to move the substrate at a constant speed during scanning exposure of the substrate, but in order to improve throughput (productivity), it is desirable to accelerate and / or decelerate the substrate during scanning exposure. Patent Document 1 proposes a scanning exposure apparatus that improves throughput by performing scanning exposure of the substrate while accelerating and / or decelerating the substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-142463 A Summary of the Invention [Problem to be solved by the invention]

[0004] When scanning exposure of a substrate is performed while accelerating and / or decelerating the substrate as described in Patent Document 1, the exposure time may change according to the speed of the substrate. Therefore, in order to make the exposure amount in scanning exposure constant (uniform), it is necessary to change the illuminance of the substrate (i.e., the intensity of light irradiated onto the substrate) according to the speed of the substrate. In Patent Document 1, the illuminance of the substrate is controlled by controlling the light source based on the drive profile of the substrate stage, but it is desired to control the illuminance of the substrate using a simpler method and mechanism.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide an advantageous technique for changing the illuminance of a substrate in accordance with the speed of the substrate during scanning exposure. [Means for solving the problem]

[0006] In order to achieve the above object, an illumination optical system according to one aspect of the present invention comprises: In scanning exposure of the substrate, linearly polarized light (P-polarized light) Using Original version An illumination optical system for illuminating the Linearly polarized A first light transmitting member disposed on the optical path of and arranged on the optical path of the linearly polarized light transmitted through the first light transmitting member. A second light transmitting member; In the scanning exposure, according to the speed of the substrate, The first light transmitting member and one of the second light transmitting members to The linearly polarized light The angle of incidence While increasing, the first light transmitting member and The second light transmitting member The other to The linearly polarized light The angle of incidence Decrease Thus, the first light transmitting member and the second light transmitting member is driven, It is characterized by:

[0007] Further objects and other aspects of the present invention will become apparent from the following description of preferred embodiments with reference to the accompanying drawings. Effect of the Invention

[0008] According to the present invention, for example, it is possible to provide an advantageous technique for changing the illuminance of a substrate in response to the speed of the substrate in scanning exposure. [Brief description of the drawings]

[0009] [Figure 1] Schematic diagram showing an example of the configuration of an exposure apparatus [Diagram 2] A diagram showing the acceleration, speed, and illuminance of the substrate when performing scanning exposure. [Diagram 3] FIG. 13 is a diagram showing the relationship between the angle of incidence and transmittance of light (P-polarized light) in each of a first light transmitting member and a second light transmitting member. [Figure 4] FIG. 13 is a diagram showing an example of driving a first light transmitting member and a second light transmitting member in scanning exposure of one shot area. [Diagram 5]FIG. 1 shows an example of incident angle control in scanning exposure of one shot area. [Figure 6] FIG. 1 is a diagram showing changes in light transmittance in a transmittance varying mechanism. [Figure 7] A diagram showing the relationship between the angle of incidence and the shift amount of the optical axis A. [Figure 8] FIG. 13 is a diagram showing a configuration example of a transmittance varying mechanism according to a second embodiment; [Figure 9] FIG. 13 is a diagram showing a composite transmittance in the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0011] First Embodiment An exposure apparatus 100 according to a first embodiment of the present invention will be described. The exposure apparatus 100 of this embodiment performs scanning exposure to transfer a pattern of the original M onto the substrate by exposing the substrate W while scanning the original M and the substrate W arranged via the projection optical system PO relatively. The scanning exposure can be performed on each of a plurality of shot areas on the substrate W. In the following description, the direction parallel to the optical axis of the projection optical system PO is defined as the Z direction, and two directions orthogonal to each other in a plane perpendicular to the Z direction are defined as the X direction and the Y direction.

[0012] [Configuration of exposure equipment] 1 is a schematic diagram showing an example of the configuration of an exposure apparatus 100 of this embodiment. The exposure apparatus 100 may include an illumination optical system IL that illuminates an original M using a light beam from a light source 1, a projection optical system PO that projects an image of the pattern of the original M illuminated by the illumination optical system IL onto a substrate W, and a controller CNT. The controller CNT is configured by a computer including, for example, a CPU, a memory, and the like, and controls each part of the exposure apparatus 100 (controls the scanning exposure of the substrate W). Here, for example, a mask or a reticle may be used as the original M, and for example, a wafer or a glass plate (liquid crystal substrate) may be used as the substrate W.

[0013] The light source 1 emits a light beam (light) for exposing the substrate W. The light source 1 in this embodiment is configured (arranged) so that linearly polarized light (P-polarized light) is incident on the transmittance varying mechanism 5 described below. As an example, when a laser light source such as an excimer laser is used as the light source 1, the light (laser light) emitted from the laser light source is generally linearly polarized light, so the light source 1 can be arranged so that the linearly polarized light incident on the transmittance varying mechanism 5 is P-polarized light. On the other hand, when an LED or a mercury lamp is used as the light source 1, a polarizer for reducing S-polarized light can be provided in the light source 1 so that linearly polarized light (P-polarized light) is incident on the transmittance varying mechanism 5.

[0014] The projection optical system IL may include a deflection optical system 2, a variable transmittance mechanism 5, an exit angle conservation optical element 6, a diffractive optical element 7, a condenser lens 8, and a prism unit 10. The projection optical system IL may further include a zoom lens unit 11, a multi-beam forming unit 12, a diaphragm 13, and a condenser lens 14.

[0015] The deflection optical system 2 is provided between the light source 1 and the exit angle preserving optical element 6, and guides the light beam emitted from the light source 1 to the exit angle preserving optical element 6. In the present embodiment, the light beam emitted from the deflection optical system 2 is reflected by a mirror 3 and enters the illumination optical system IL via a parallel plane plate 4. The mirror 3 and the parallel plane plate 4 make it possible to adjust the position and angle of the light beam entering the exit angle preserving optical element 6.

[0016] The variable transmittance mechanism 5 can be disposed on the optical path between the light source 1 and the exit angle preserving optical element 6. The variable transmittance mechanism 5 is a mechanism for changing the intensity of light emitted from the illumination optical system IL in scanning exposure (i.e., the illuminance of light irradiated onto the original and / or substrate), and may be understood as a light intensity variable mechanism or an illuminance variable mechanism. The variable transmittance mechanism 5 is configured to be able to change the transmittance of light, and transmits the light incident on the variable transmittance mechanism 5 at a desired transmittance, thereby controlling the intensity of the light beam incident on the exit angle preserving optical element 6 and controlling the intensity of the light emitted from the illumination optical system IL. The detailed configuration of the variable transmittance mechanism 5 will be described later.

[0017] The exit angle preserving optical element 6 is an optical element for making the illuminance of the light beam irradiated onto the original M uniform, and can be placed on the optical path on the light source side of the diffractive optical element 7 (i.e., between the transmittance varying mechanism 5 and the diffractive optical element 7). The exit angle preserving optical element 6 includes an optical integrator such as a microlens array, a fiber bundle, or a fly-eye lens, and guides the light beam from the light source 1 to the diffractive optical element 7 while maintaining the divergence angle constant. This makes it possible to reduce the effect of output fluctuations of the light source 1 on the pattern distribution formed by the diffractive optical element 7.

[0018] The diffractive optical element 7 is disposed on the optical path between the exit angle conservation optical element 6 and the condenser lens 8, and diffracts the light beam from the exit angle conservation optical element 6 and guides it to the condenser lens 8. The diffractive optical element 7 converts the light intensity distribution of the light beam from the light source 1 by diffraction effect to form a desired light intensity distribution on the pupil plane of the illumination optical system IL, which is a plane conjugate with the pupil plane of the projection optical system PO, or on a plane conjugate with the pupil plane of the illumination optical system IL. The light source shape (light intensity distribution) formed on the pupil plane of the projection optical system PO in this way is called an effective light source shape. As the diffractive optical element 7, a computer generated hologram (CGH) designed by a computer so that a desired diffraction pattern is obtained on the diffraction pattern plane may be used.

[0019] Condenser lens 8 is disposed on the optical path between diffractive optical element 7 and prism unit 10, and collects the light beam diffracted by diffractive optical element 7 to form a diffraction pattern on Fourier transform surface 9. Fourier transform surface 9 is a surface that is in an optically Fourier transform relationship with diffractive optical element 7, between multi-beam forming unit 12 (optical integrator) and diffractive optical element 7. Therefore, by replacing (changing) diffractive optical element 7, the shape of the diffraction pattern formed on Fourier transform surface 9 can be changed.

[0020] The prism unit 10 and the zoom lens unit 11 are disposed on the optical path between the Fourier transform surface 9 and a multi-beam forming section 12 (optical integrator), and function as a zoom optical system that expands the light intensity distribution formed on the Fourier transform surface 9. The prism unit 10 can guide the diffraction pattern (light intensity distribution) formed on the Fourier transform surface 9 to the zoom lens unit 11 by adjusting the annular ratio and the like. The zoom lens unit 11 is disposed on the optical path between the prism unit 10 and the multi-beam forming section 12, and may include a first lens 11a and a second lens 11b. The zoom lens unit 11 can guide the diffraction pattern formed on the Fourier transform surface 9 to the multi-beam forming section 12 by adjusting a σ value based on the ratio between the NA (numerical aperture) of the illumination optical system IL and the NA (numerical aperture) of the projection optical system PO.

[0021] The multi-beam forming section 12 is provided on the optical path between the zoom lens unit 11 and the condenser lens 14, and forms a number of secondary light sources according to a diffraction pattern in which the annular ratio, the aperture angle, and the σ value have been adjusted, and guides the light to the condenser lens 14. The multi-beam forming section 12 may include a fly-eye lens as an optical integrator, but may include other optical integrators such as an optical pipe, a diffractive optical element, or a microlens array instead of or in addition to the fly-eye lens. By providing this multi-beam forming section 12, the original M, which is a non-illuminated surface, can be uniformly illuminated with the light beam that has passed through the diffractive optical element 7. In addition, a diaphragm 13 is provided between the multi-beam forming section 12 and the condenser lens 14.

[0022] A half mirror 15 is provided behind the condenser lens 14, and a part of the light beam from the condenser lens 14 is guided to a detection unit 17 via an optical system 16. The detection unit 17 includes a sensor that detects the intensity of the incident light. This allows the control unit CNT to accurately control the exposure amount of the substrate W based on the detection result of the detection unit 17.

[0023] The original M is provided between the condenser lens 14 and the projection optical system PO, and has a circuit pattern to be transferred onto the substrate. The original M is held and driven by an original stage (not shown). The projection optical system PO is provided between the original M and the substrate W, and maintains the original M and the substrate W in an optically conjugate relationship. The substrate W is held and driven by a substrate stage (not shown). In the exposure apparatus 100 configured in this manner, a pattern can be formed on the substrate by performing so-called scanning exposure, in which the image of the pattern of the original M illuminated by the illumination optical system IL is projected onto the substrate W by the projection optical system PO while scanning the original M and the substrate W.

[0024] Here, the substrate W has a plurality of shot areas to which the pattern of the original M should be transferred, i.e., to which scanning exposure should be performed. Movement from one shot area to the next shot area is performed by a reciprocating scan operation in the scanning direction. In addition, in the direction perpendicular to the scanning direction, a step operation is performed from the completion of scanning exposure of one shot area to the start of scanning exposure of the next shot area. In addition, the resolution of the pattern of the original M depends on the effective light source shape, and the resolution of the pattern can be improved by forming an appropriate effective light source distribution.

[0025] [Scanning exposure] In order to improve throughput (productivity), the exposure apparatus 100 of this embodiment controls the scanning exposure so that the scanning exposure includes an acceleration section for accelerating the substrate W and a deceleration section for decelerating the substrate W. For example, FIG. 2 shows the acceleration, velocity, and illuminance of the substrate W when scanning exposure is performed on each of a plurality of shot areas on the substrate W. As shown in FIG. 2, the exposure apparatus 100 drives the substrate W according to a sinusoidal velocity profile, and scanning exposure of each shot area can be performed in a part of the velocity profile that includes the acceleration section and the deceleration section. That is, the velocity of the substrate W in the scanning exposure of each shot area can be determined by a part of the sinusoidal velocity profile that includes the acceleration section and the deceleration section. Such a scanning exposure method can be called sinusoidal exposure.

[0026] In this manner, in the scanning exposure including the acceleration section and the deceleration section, the exposure time changes depending on the speed of the substrate W for each position in the shot area in the scanning direction. Therefore, in order to make the exposure amount constant (uniform) for each position in the shot area, it is necessary to change the illuminance of the substrate W (i.e., the intensity of the light irradiated to the substrate W) with a predetermined illuminance profile according to the speed of the substrate W. For example, in the case of sinusoidal exposure, as shown in FIG. 2, in order to make the exposure amount in the scanning exposure constant, it is preferable to change the illuminance of the substrate W according to a sinusoidal illuminance profile according to the sinusoidal speed of the substrate W. In the example of FIG. 2, the scanning exposure is performed by changing the speed of the substrate W by 80% or more of the maximum speed, so that the illuminance of the substrate W is changed sinusoidally to increase from 80% to 100% and decrease from 100% to 80% to follow this. In the exposure apparatus 100 of this embodiment, the intensity of the light emitted from the illumination optical system IL during scanning exposure (hereinafter, this may be referred to as the light intensity of the illumination optical system IL) is changed by the transmittance varying mechanism 5 in accordance with the speed of the substrate W, thereby changing the illuminance of the substrate W.

[0027] [Configuration of variable transmittance mechanism] Next, a configuration example of the transmittance variable mechanism 5 will be described. The transmittance variable mechanism 5 of this embodiment may include a first light transmitting member 51 and a second light transmitting member 52 arranged on the optical path as shown in FIG. 1. The first light transmitting member 51 and the second light transmitting member 52 are each composed of a single parallel flat plate and arranged at an interval from each other in the optical axis direction. The first light transmitting member 51 is configured to be rotatable by a first driving unit 51b about a first rotating shaft 51a intersecting with the optical axis so as to be able to change an angle θ1 (hereinafter, sometimes referred to as an incident angle θ1) between the normal to the surface of the first light transmitting member 51 and the optical axis. The second light transmitting member 52 is configured to be rotatable by a second driving unit 52a about a second rotating shaft 52a intersecting with the optical axis so as to be able to change an angle θ2 (hereinafter, sometimes referred to as an incident angle θ2) between the normal to the surface of the second light transmitting member 52 and the optical axis. Here, the first rotation axis 51a and the second rotation axis 52a are preferably perpendicular to the optical axis and parallel to each other. Furthermore, each of the first rotation axis 51a and the second rotation axis 52a is preferably set to be perpendicular to the polarization plane (vibration plane) of the linearly polarized light that is incident as P-polarized light on the transmittance varying mechanism 5 (the first light transmitting member 51 and the second light transmitting member 52).

[0028] From the viewpoint of facilitating control of the intensity of light emitted from the illumination optical system IL in scanning exposure, the first light transmitting member 51 and the second light transmitting member 52 are preferably made of the same glass material and have similar transmittance. FIG. 3 shows the relationship between the incidence angle of light (P-polarized light) and the transmittance in each of the first light transmitting member 51 and the second light transmitting member 52. FIG. 3 shows an example in which each of the first light transmitting member 51 and the second light transmitting member 52 is made of quartz, and the Brewster's angle in this case is 56.5 degrees. The Brewster's angle is the incidence angle when the transmitted light and the reflected light are perpendicular, and when the incidence angle of the P-polarized light is the Brewster's angle, the transmittance of the P-polarized light is 100%.

[0029] The transmittance varying mechanism 5 configured as described above can change the light intensity of the projection optical system IL by driving (rotating) the first light transmitting member 51 by the first driving unit 51a and driving (rotating) the second light transmitting member 52 by the second driving unit 52b. The driving of the first light transmitting member 51 and the second light transmitting member 52 can be controlled by the control unit CNT so that the light intensity of the illumination optical system IL in the scanning exposure changes with a predetermined light intensity profile. The predetermined light intensity profile can be a profile of the light intensity of the illumination optical system IL set so that the illuminance of the substrate W in the scanning exposure changes with a predetermined illuminance profile (for example, a sinusoidal illuminance profile shown in FIG. 2). In the case of this embodiment, the control unit CNT drives one of the light transmitting members 51-52 in the scanning exposure so that the incident angle of light to the one of the light transmitting members 51-52 increases within a first angle range. In addition, the control unit CNT drives the other of the light transmitting members 51-52 in the scanning exposure in parallel with driving the one of the light transmitting members 51-52 so that the incident angle of light to the other of the light transmitting members 51-52 decreases within a second angle range. This makes it possible to change the light intensity of the illumination optical system IL according to a predetermined light intensity profile.

[0030] Here, the first angle range and the second angle range are set to include the Brewster angle. The first angle range and the second angle range may be set to include a common angle range, or may be set to the same angle range. Also, each of the first angle range and the second angle range may be set to have the Brewster angle as a central angle. By setting the first angle range and the second angle range in this way, it is possible to easily control the light intensity of the illumination optical system IL, and to realize a light intensity profile corresponding to the sinusoidal illuminance profile shown in FIG. 2.

[0031] [Example of driving light-transmitting components] Next, an example of driving the first light transmitting member 51 and the second light transmitting member 52 will be described. Fig. 4 shows an example of driving the first light transmitting member 51 and the second light transmitting member 52 in scanning exposure (one scanning exposure) of one shot area. As described above, linearly polarized light (P polarized light) is incident on the first light transmitting member 51 and the second light transmitting member 52. In Fig. 4, the optical axis A (principal ray) of the linearly polarized light is shown.

[0032] Here, an example will be described in which, in one scanning exposure, the first light transmitting member 51 is driven so that the incident angle θ1 increases within a first angle range, while the second light transmitting member 52 is driven so that the incident angle θ2 decreases within a second angle range. The first angle range and the second angle range can be set to a common angle range (39 degrees to 74 degrees) including the Brewster's angle (56.5 degrees). In addition, the first light transmitting member 51 and the second light transmitting member 52 can be driven so that the absolute value of the difference between the incident angle θ1 of light to the first light transmitting member 51 and the Brewster's angle becomes equal to the absolute value of the difference between the incident angle θ2 of light to the second light transmitting member 52 and the Brewster's angle. 5, in one scanning exposure, the first light transmitting member 51 can be driven in one direction so that the incident angle θ1 increases linearly from 39 degrees to 74 degrees, and the second light transmitting member 52 can be driven in one direction so that the incident angle θ2 decreases linearly from 74 degrees to 39 degrees. In other words, the driving direction of the first light transmitting member 51 and the driving direction of the second light transmitting member 52 are not changed (reversed) during one scanning exposure.

[0033] FIG. 4(a) shows the arrangement of the first light transmitting member 51 and the second light transmitting member 52 at the start of the scanning exposure. At the start of the scanning exposure, the first light transmitting member 51 is arranged so that the incident angle θ1 is 39 degrees, and the second light transmitting member 52 is arranged so that the incident angle θ2 is 74 degrees. Then, as the scanning exposure progresses, the first light transmitting member 51 and the second light transmitting member 52 are driven (rotated). FIG. 4(b) shows the arrangement of the first light transmitting member 51 and the second light transmitting member 52 when the incident angle θ1 and the incident angle θ2 both become Brewster's angle (56.5 degrees) during the scanning exposure. The control unit CNT may control the driving of the first light transmitting member 51 and the second light transmitting member 52 so that the arrangement of FIG. 4(b) is achieved when the speed of the substrate W in the scanning exposure is at the maximum speed. Also, FIG. 4(c) shows the arrangement of the first light transmitting member 51 and the second light transmitting member 52 at the end of the scanning exposure. At the end of the scanning exposure, the first light transmitting member 51 is positioned so that the incident angle θ1 is 74 degrees, and the second light transmitting member 52 is positioned so that the incident angle θ2 is 39 degrees.

[0034] Here, in the next scanning exposure, the driving direction of the first light transmitting member 51 and the driving direction of the second light transmitting member 52 may be inverted (reversed). Specifically, in the next scanning exposure, the first light transmitting member 51 may be driven so that the incident angle θ1 decreases within a first angle range, while the second light transmitting member 52 may be driven so that the incident angle θ2 increases within a second angle range. This makes it unnecessary to return the first light transmitting member 51 and the second light transmitting member 52 to their original positions every time scanning exposure is performed, and therefore it is possible to simplify the control of the driving of the first light transmitting member 51 and the second light transmitting member 52. Note that the reversal of the driving direction may be performed during the step movement of the substrate W that is performed between the end of scanning exposure of one shot area and the start of the next scanning exposure.

[0035] FIG. 6 is a diagram showing a change in light transmittance in the transmittance varying mechanism 5. As shown in FIG. 6(a) shows the transmittance characteristics (relationship between incident angle θ1 and transmittance) of the first light transmitting member 51 in an angle range (first angle range, second angle range) of 39 degrees to 74 degrees. When the first light transmitting member 51 and the second light transmitting member 52 are made of the same glass material, the transmittance characteristics (relationship between incident angle θ2 and transmittance) of the second light transmitting member 52 are also the characteristics shown in FIG. 6(a) like the first light transmitting member 51.

[0036] FIG. 6(b) shows a result of combining the transmittance of the first light transmitting member 51 and the transmittance of the second light transmitting member 52 in an angle range of 39 degrees to 74 degrees (hereinafter, sometimes referred to as a composite transmittance). In FIG. 6(b), the horizontal axis represents the incident angle θ1 of light to the first light transmitting member 51, and the horizontal axis represents the composite transmittance. As described above, in the transmittance varying mechanism 5 of this embodiment, in the scanning exposure, the incident angle of light to one of the first light transmitting member 51 and the second light transmitting member 52 is linearly increased from 39 degrees to 74 degrees, while the incident angle of light to the other is linearly decreased from 74 degrees to 39 degrees. In this case, one of the incident angles θ1 and θ2 is larger than the Brewster's angle (56.5 degrees), and the other is smaller than the Brewster's angle, and the absolute values ​​of the difference from the Brewster's angle are equal to each other. Therefore, the shape of the composite transmittance within the angle range can be made symmetrical with respect to the Brewster angle, and the light intensity profile of the illumination optical system IL corresponding to the illuminance profile shown in Fig. 2 can be realized. Here, in the transmittance varying mechanism 5 of this embodiment, by changing the angle range for each of the incidence angle θ1 and the incidence angle θ2, the light intensity profile of the illumination optical system IL can be changed. In other words, the angle range can be appropriately changed according to the target profile of the light intensity emitted from the illumination optical system IL in scanning exposure.

[0037] [Optical axis shift amount] Next, the shift amount of the optical axis A in the transmittance varying mechanism 5 will be described. In this embodiment, the shift amount of the optical axis A can be defined as the difference between the optical axis of the incident light that enters the light transmitting member and the optical axis of the transmitted light that passes through the light transmitting member and is emitted from the light transmitting member. In addition, the fluctuation (amount of fluctuation) of the optical axis A can be defined as the fluctuation (amount of fluctuation) of the optical axis A of the transmitted light that occurs when the light transmitting member is driven (rotated) within a predetermined angle range (for example, 39 degrees to 74 degrees).

[0038] Since the first light transmitting member 51 is composed of a parallel plane plate, a shift amount of the optical axis A occurs according to the incident angle θ1 of light to the first light transmitting member 51, and when the incident angle θ1 is changed, the shift amount of the optical axis A can vary accordingly. Similarly, since the second light transmitting member 52 is also composed of a parallel plane plate, a shift amount of the optical axis A occurs according to the incident angle θ2 of light to the second light transmitting member 52, and when the incident angle θ is changed, the shift amount of the optical axis A can vary accordingly.

[0039] In this embodiment, since the first light transmitting member 51 and the second light transmitting member 52 are used, the shift amount of the optical axis A caused by the first light transmitting member 51 and the shift amount of the optical axis A caused by the second light transmitting member 52 are synthesized (added together). This synthesized shift amount is larger than the shift amount of the optical axis A in a single light transmitting member, but the fluctuation in the synthesized shift amount caused by driving the first light transmitting member 51 and the second light transmitting member 52 as described above is smaller than the fluctuation in the shift amount of the optical axis A in a single light transmitting member.

[0040] FIG. 7 shows the relationship between the incident angle of light and the shift amount of the optical axis A when the thickness of both the first light transmitting member 51 and the second light transmitting member 52 is 2 mm. The horizontal axis of FIG. 7 represents the angle range (39 degrees to 74 degrees) of the incident angle θ1 of light to the first light transmitting member 51, and when considering the angle range of the incident angle θ2 of light to the second light transmitting member 52, the angle range of the horizontal axis can be the inverted angle range (74 degrees to 39 degrees). In addition, in FIG. 7, line (a) shows the shift amount of the optical axis A in the first light transmitting member 51 alone, and line (b) shows the shift amount of the optical axis A in the second light transmitting member 52 alone. Line (c) shows the shift amount of the optical axis A when the transmittance variable mechanism 5 is viewed as a whole, that is, the shift amount of the optical axis A when both the first light transmitting member 51 and the second light transmitting member 52 are used. The shift amount of optical axis A shown by line (c) may be understood as the result of combining the shift amount of optical axis A shown by line (a) and the shift amount of optical axis A shown by line (b) (hereinafter, this may be referred to as the combined shift amount).

[0041] In Fig. 7, when the incident angle θ1 is 39 degrees (i.e., when the incident angle θ2 is 74 degrees), the shift amount of the optical axis A due to the first light transmitting member 51 is 0.52 mm, the shift amount of the optical axis A due to the second light transmitting member 52 is 1.45 mm, and the composite shift amount is 1.97 mm. When the incident angle θ1 and the incident angle θ2 are both 56.5 degrees (Brewster's angle), the shift amount of the optical axis A due to the first light transmitting member 51 and the shift amount of the optical axis A due to the second light transmitting member 52 are both 0.905 mm, and the composite shift amount is 1.81 mm. When the incident angle θ1 is 74 degrees (i.e., when the incident angle θ2 is 39 degrees), the shift amount of the optical axis A due to the first light transmitting member 51 is 1.45 mm, the shift amount of the optical axis A due to the second light transmitting member 52 is 0.52 mm, and the composite shift amount is 1.97 mm.

[0042] In this way, in the case of a single light transmitting member (first light transmitting member 51, second light transmitting member 52), the shift amount of the optical axis A can vary by 0.93 mm, from 0.52 mm to 1.45 mm, in the angle range of 39 degrees to 74 degrees. On the other hand, the composite shift amount is an average of 1.89 mm, a minimum of 1.81 mm, and a maximum of 1.97 mm in the angle range of 39 degrees to 74 degrees, and can be suppressed to a variation of 0.16 mm. In other words, by displacing the optical axis of the plane-parallel plate 4 and the optical axis of the exit angle preserving optical element 6 by an average composite shift amount of 1.89 mm, the variation amount of the optical axis due to the driving of the first light transmitting member 51 and the second light transmitting member 52 can be suppressed to ±0.08 mm.

[0043] When the optical axis of the light incident on the exit angle conservation optical element 6 fluctuates, the light beam incident on the Fourier transform surface 9 is tilted. The tolerance for fluctuation of the optical axis of the light incident on the exit angle conservation optical element 6 is ±0.5 mm. In the above example, the fluctuation of the optical axis is ±0.08 mm, which is sufficiently smaller than the tolerance (±0.5 mm). Although each of the first light transmitting member 51 and the second light transmitting member 52 may be made thicker than 2 mm to increase rigidity, it is preferable to set (determine) the thickness of each light transmitting member 51 to 52 so that the fluctuation of the optical axis falls within the tolerance (within ±0.5 mm).

[0044] As described above, in this embodiment, in one scanning exposure, one of the light transmitting members 51-52 is driven so that the angle of incidence of light to the one of the light transmitting members 51-52 increases within a first angle range, while the other is driven so that the angle of incidence of light to the other of the light transmitting members 51-52 decreases within a second angle range. However, the first angle range and the second angle range each include the Brewster's angle. As a result, in the scanning exposure (for example, sinusoidal exposure) of one shot area, the light intensity of the illumination optical system IL (i.e., the illuminance of the substrate W) can be changed according to the speed of the substrate W, so that the exposure amount in the one shot area can be made uniform. Also, in this embodiment, the driving direction of each of the light transmitting members 51-52 is not reversed in one scanning exposure, so that the load on the motor (first driving unit 51b, second driving unit 52b) due to the reversal can be reduced. In other words, the configuration of the transmittance varying mechanism 5 can be simplified (for example, the motor can be made smaller), and the device can be prevented from becoming large. In the above, an example in which two light transmitting members (first light transmitting member 51 and second light transmitting member 52) are used has been described, but three or more light transmitting members may be used.

[0045] <Second embodiment> A second embodiment of the present invention will be described. In this embodiment, an example will be described in which each of the first light transmitting member 51 and the second light transmitting member 52 is composed of a plurality of parallel flat plates arranged with a gap therebetween along the optical axis A. Note that this embodiment basically follows on from the first embodiment, and the configuration and processing of the exposure apparatus 100 (for example, the method of driving the first light transmitting member 51 and the second light transmitting member 52) are as described in the first embodiment.

[0046] FIG. 8 shows a configuration example of the transmittance variable mechanism 5' (first light transmitting member 51, second light transmitting member 52) of this embodiment. As shown in FIG. 8, the first light transmitting member 51 is composed of two parallel plane plates 511-512 arranged with a gap therebetween along the optical axis A, and the two parallel plane plates 511-512 are driven (rotated) as a unit by the first driving unit 51b. This makes it possible to change the incident angle θ1 of light to the first light transmitting member 51 (parallel plane plate 511). The second light transmitting member 52 is composed of two parallel plane plates 521-522 arranged with a gap therebetween along the optical axis A, and the two parallel plane plates 521-522 are driven (rotated) as a unit by the second driving unit 52b. This makes it possible to change the incident angle θ2 of light to the second light transmitting member 52 (parallel plane plate 521).

[0047] FIG. 9 shows a result (composite transmittance) of combining the transmittance of the first light transmitting member 51 (parallel plane plates 511-512) and the transmittance of the second light transmitting member 52 (parallel plane plates 521-522) in an angle range of 39 degrees to 74 degrees. As shown in FIG. 9, in the transmittance varying mechanism 5' of this embodiment, the composite transmittance can be changed (enlarged) more significantly in an angle range of 39 degrees to 74 degrees than in the transmittance varying mechanism 5 of the first embodiment. However, in the transmittance varying mechanism 5' of this embodiment, the amount of fluctuation of the optical axis is larger than in the transmittance varying mechanism 5 of the first embodiment. Therefore, it is preferable to determine (set) the thickness of each of the parallel plane plates 511-512, 521-522 so that the amount of fluctuation of the optical axis falls within the allowable amount (±0.5 mm).

[0048] As described above, in this embodiment, each of the first light transmitting member 51 and the second light transmitting member 52 is composed of a plurality of parallel plane plates arranged at intervals along the optical axis. This makes it possible to increase the combined transmittance of the first light transmitting member 51 and the second light transmitting member 52 in a predetermined angle range. Note that, although an example in which each of the light transmitting members 51-52 is composed of two parallel plane plates has been described in this embodiment, each of the light transmitting members 51-52 may be composed of three or more parallel plane plates.

[0049] <Embodiments of the method for manufacturing an article> The method for manufacturing an article according to an embodiment of the present invention is suitable for manufacturing an article such as a microdevice such as a semiconductor device or an element having a fine structure. The method for manufacturing an article according to this embodiment includes a step of forming a latent image pattern on a photosensitive agent applied to a substrate using the above-mentioned exposure apparatus (a step of exposing the substrate), and a step of developing (processing) the substrate on which the latent image pattern has been formed in this step. Furthermore, this manufacturing method includes other well-known steps (oxidation, film formation, deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, etc.). The method for manufacturing an article according to this embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of the article compared to conventional methods.

[0050] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0051] 1: light source, 5: transmittance variable mechanism, 51: first light transmitting member, 52: second light transmitting member, 6: exit angle preserving optical element, IL: illumination optical system, M: original, PO: projection optical system, W: substrate, 100: exposure apparatus

Claims

1. An illumination optical system for illuminating an original using linearly polarized light that is P-polarized light in a scanning exposure of a substrate, comprising: A first light transmitting member disposed on an optical path of the linearly polarized light; a second light transmitting member disposed on an optical path of the linearly polarized light transmitted through the first light transmitting member, an illumination optical system including: a first light transmitting member and a second light transmitting member that are driven in the scanning exposure so as to increase an incident angle of the linearly polarized light onto one of the first light transmitting member and the second light transmitting member while decreasing an incident angle of the linearly polarized light onto the other of the first light transmitting member and the second light transmitting member in accordance with a speed of the substrate;

2. In the scanning exposure, the first light-transmitting member and the second light-transmitting member are driven so as to increase the angle of incidence of the linearly polarized light on one of the members within a first angle range while decreasing the angle of incidence of the linearly polarized light on the other member within a second angle range according to a speed of the substrate; 2. The illumination optical system of claim 1, wherein the first angle range and the second angle range each include Brewster's angle.

3. the first light transmitting member is disposed on the optical path so as to be rotatable about a first rotation axis that intersects with an optical axis of the linearly polarized light; 3. The illumination optical system according to claim 1, wherein the second light transmitting member is disposed on the optical path so as to be rotatable about a second rotation axis that intersects with the optical axis.

4. 4. The illumination optical system according to claim 3, wherein the first rotation axis and the second rotation axis are parallel to each other.

5. 5. The illumination optical system according to claim 1, wherein each of the first light transmitting member and the second light transmitting member is a single plane-parallel plate.

6. 6. The illumination optical system according to claim 1, wherein each of the first light transmitting member and the second light transmitting member includes a plurality of parallel plane plates arranged at intervals along the optical axis direction of the linearly polarized light.

7. further comprising an optical element for making the illuminance of the light irradiated onto the original uniform; 7. The illumination optical system according to claim 1, wherein the first light transmitting member and the second light transmitting member are arranged on an optical path between a light source that emits the linearly polarized light and the optical element.

8. 8. The illumination optical system according to claim 1, wherein the first light transmitting member and the second light transmitting member are arranged at an interval from each other in a direction of an optical axis of the linearly polarized light.

9. 9. The illumination optical system according to claim 1, wherein the first light transmitting member and the second light transmitting member have a thickness such that an amount of fluctuation of the optical axis of the linearly polarized light, which fluctuates by driving the first light transmitting member and the second light transmitting member, is within ±0.5 mm.

10. An exposure apparatus for performing scanning exposure of a substrate, comprising: an illumination optical system that illuminates an original using linearly polarized light that is P-polarized light; a projection optical system that projects an image of the pattern of the original onto the substrate; a control unit for controlling the illumination optical system, the illumination optical system includes a first light transmitting member arranged on an optical path of the linearly polarized light, and a second light transmitting member arranged on an optical path of the linearly polarized light transmitted through the first light transmitting member, an exposure apparatus comprising: a control unit that controls driving of the first light transmitting member and the second light transmitting member in the scanning exposure so as to increase an incident angle of the linearly polarized light onto one of the first light transmitting member and the second light transmitting member while decreasing an incident angle of the linearly polarized light onto the other of the first light transmitting member and the second light transmitting member in accordance with a speed of the substrate.

11. the control unit controls driving of the first light transmitting member and the second light transmitting member so as to increase an incident angle of the linearly polarized light onto one of the light beams within a first angle range while decreasing an incident angle of the linearly polarized light onto the other light beam within a second angle range in accordance with a speed of the substrate, during the scanning exposure; 11. The exposure apparatus of claim 10, wherein the first angle range and the second angle range each include Brewster's angle.

12. 12. The exposure apparatus according to claim 10, wherein the control unit does not change the driving direction of the first light transmitting member and the driving direction of the second light transmitting member during the scanning exposure.

13. 13. The exposure apparatus according to claim 10, wherein the scanning exposure includes an acceleration section in which the substrate is accelerated and a deceleration section in which the substrate is decelerated.

14. 14. The exposure apparatus according to claim 13, wherein the velocity of the substrate in the scanning exposure is determined by a portion of a sinusoidal velocity profile that includes the acceleration section and the deceleration section.

15. an exposure step of exposing a substrate using the exposure apparatus according to any one of claims 10 to 14; a processing step of processing the substrate exposed in the exposure step, A method for manufacturing an article, comprising the steps of: manufacturing an article from the substrate processed in the processing step.

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