Exposure device and method for manufacturing article

Abstract

The present invention relates to an exposure device and a method for manufacturing an article. A technology is provided that facilitates the measurement of optical characteristics of a projection optical system with good accuracy. An exposure device for exposing a substrate comprises: a projection optical system that projects a pattern image of an original onto the substrate using exposure light; a measuring unit that measures the optical characteristics of the projection optical system using measurement light emitted from the projection optical system via an optical element of the projection optical system through which the exposure light is to pass; and a control unit that corrects the irradiation position of the exposure light on the substrate based on the measurement result of the measuring unit, the measuring unit comprising a light receiving element that receives the measurement light, and the light receiving element is mounted on the projection optical system.

Description

Technical Field

[0001] The present invention relates to an exposure device and a method for manufacturing an article. Background Art

[0002] In the photolithography process, which is one of the manufacturing processes of semiconductor devices, liquid crystal displays, etc., an exposure device is used to expose a substrate by projecting a pattern image of an original onto the substrate via a projection optical system. In the exposure device, for example, with the miniaturization of semiconductor devices, etc., it is required to transfer the pattern of the original onto the substrate with good accuracy, and changes in the optical characteristics of the projection optical system during the exposure process of the substrate may become a major cause of reduced transfer accuracy. Changes in the optical characteristics of the projection optical system may be caused by, for example, vibrations of optical elements included in the projection optical system, temperature changes in the projection optical system, pressure changes, etc. Patent document 1 discloses a structure in which a measurement mark is arranged near the original, and the optical characteristics (imaging performance) of the projection optical system are corrected based on the position of the projection image obtained by receiving the projection image of the measurement mark by the projection optical system through the light receiving unit.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-72678 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] In the structure described in Patent Document 1, the measurement mark is provided on a member fixed to the main body of the exposure device, and the light receiving unit that receives the projection image of the measurement mark is fixed to the same structure as the measurement mark (the main body of the exposure device). In other words, the projection optical system and the light receiving unit are separately provided. However, in such a structure, the relative position of the projection optical system and the light receiving unit sometimes changes, so it may be difficult to accurately measure the optical characteristics of the projection optical system based on the light receiving result of the projection image of the measurement mark by the light receiving unit.

[0008] Therefore, an object of the present invention is to provide a technology that is useful for measuring the optical characteristics of a projection optical system with high accuracy.

[0009] Solutions for solving problems

[0010] In order to achieve the above-mentioned purpose, an exposure device as one aspect of the present invention exposes a substrate, and the exposure device is characterized in that it includes: a projection optical system that uses exposure light to project a pattern image of an original plate onto the substrate; a measuring unit that uses measurement light emitted from the projection optical system via an optical element of the projection optical system through which the exposure light is to pass, to measure the optical characteristics of the projection optical system; and a control unit that corrects the irradiation position of the exposure light on the substrate based on the measurement result of the measuring unit, and the measuring unit includes a light receiving element that receives the measurement light, and the light receiving element is installed in the projection optical system.

[0011] 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.

[0012] Effects of the Invention

[0013] According to the present invention, for example, it is possible to provide a technique useful for measuring the optical characteristics of a projection optical system with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram showing the structure of the exposure apparatus according to the first embodiment.

[0015] Figure 2 This is a diagram of the projection optical system viewed from above (from the original plate stage side).

[0016] Figure 3 It is a diagram showing the light receiving surface of the light receiving element.

[0017] Figure 4 It is a schematic diagram showing the structure of the exposure apparatus according to the third embodiment.

[0018] Figure 5 It is a schematic diagram showing the structure of the exposure apparatus according to the fourth embodiment.

[0019] Figure 6 : is a flowchart showing the exposure process.

[0020] Description of Reference Numerals

[0021] 10: illumination optical system, 20: original plate mounting table, 30: projection optical system, 40: substrate mounting table, 50: measuring section, 51: light projecting section, 52: light receiving section, 53: light receiving surface, 54: detection section, 60: control section, 100: exposure device. DETAILED DESCRIPTION

[0022] The following detailed description of the embodiments is provided with reference to the accompanying drawings. It should be noted that the following embodiments do not limit the technical solutions of the claims. A plurality of features are described in the embodiments, but all of the plurality of features are not necessarily required features of the invention. In addition, a plurality of features may be arbitrarily combined. Moreover, in the accompanying drawings, the same reference numbers are marked for the same or identical structures, and repeated descriptions are omitted.

[0023] <First Embodiment>

[0024] The exposure device 100 of the first embodiment of the present invention is described. The exposure device 100 is a photolithography device for manufacturing semiconductor devices, liquid crystal displays, etc. The exposure device 100 of this embodiment is a projection exposure device that projects a pattern image of an original plate (mask, intermediate mask) onto a substrate by a step method or a scanning method, thereby exposing the substrate and transferring the pattern of the original plate to the substrate. Hereinafter, as the exposure device 100, a scanning method exposure device that uses slit light to scan and expose the substrate is described as an example.

[0025] [Structure of exposure device]

[0026] Figure 1 1 is a schematic diagram showing the structure of the exposure device 100 of the first embodiment. The exposure device 100 of the present embodiment may include an illumination optical system 10, a movable original plate stage 20 holding an original plate M, a projection optical system 30, a movable substrate stage 40 holding a substrate W, a measuring unit 50, and a control unit 60. The control unit 60 is composed of, for example, a computer having a CPU, a memory, etc., and controls the exposure process of the substrate W (each part of the exposure device 100). The original plate M is a glass original plate in which a fine pattern (for example, a circuit pattern) to be transferred to the substrate W is formed by a light-shielding material such as chromium. In addition, as the substrate W, a semiconductor wafer, a glass plate, etc. can be used.

[0027] In order to obtain the desired illumination distribution on the master, the illumination optical system 10 shapes the light from the light source (not shown) into, for example, an arc-shaped light long in the Y-axis direction, and uses the shaped light (slit light) to illuminate the master M with a substantially uniform illumination. A mercury lamp or the like can be used as the light source. The master M and the substrate W are held by the master stage 20 and the substrate stage 40, respectively, and are arranged at positions that are substantially optically conjugate via the projection optical system 30 (the positions of the object plane and the image plane of the projection optical system 30). The projection optical system 30 has a predetermined projection magnification, and uses a plurality of reflective mirrors to reflect the pattern image of the mask 1 and project it onto the substrate 2. In addition, the mask stage 20 and the substrate stage 40 are relatively and synchronously scanned along a direction parallel to the object plane of the projection optical system 30 (for example, the X-axis direction) at a speed ratio corresponding to the projection magnification of the projection optical system 30. Thereby, scanning exposure of the substrate W can be performed, and the pattern formed on the original plate M can be transferred to the substrate W (specifically, the resist (photosensitive agent) on the substrate).

[0028] For example, Figure 1 As shown, the projection optical system 30 can be configured to include a trapezoidal mirror 31, a concave mirror 32, and a convex mirror 33. The pattern light EL (hereinafter sometimes referred to as "exposed light EL") emitted from the illumination optical system 10 and passing through the original plate M is bent by the upper surface of the trapezoidal mirror 31 and incident on the upper part of the reflecting surface of the concave mirror 32. The exposed light EL reflected at the upper part of the reflecting surface of the concave mirror 32 is reflected by the reflecting surface of the convex mirror 33 and incident on the lower part of the reflecting surface of the concave mirror 32. The exposed light EL reflected at the lower part of the reflecting surface of the concave mirror 32 is bent by the lower surface of the trapezoidal mirror 31 and incident on the substrate W. In the projection optical system 30 configured as above, the reflecting surface of the convex mirror 33 becomes the pupil. In addition, in order to avoid the magnification error caused by the position change of the original plate M and the substrate W in the optical axis direction (Z direction), the projection optical system 30 is a telecentric optical system on the original plate M side and the substrate W side, that is, the object side and the image side.

[0029] In addition, an actuator for driving each optical element may be provided in the projection optical system 30. Specifically, an actuator 34 for driving the trapezoidal mirror 31, an actuator 35 for driving the concave mirror 32, and an actuator 36 for driving the convex mirror 33 may be provided. Each actuator 34 to 36 may be used to reduce the variation (vibration) of each optical element.

[0030] Here, the actuator 35 is preferably arranged at least 3 locations with respect to the concave mirror 32. As the actuator 35, for example, an actuator such as an electromagnetic actuator which is composed of a fixed part and a movable part in a non-contact manner can be used. In this case, deformation of the concave mirror 32 caused by interference of the support part of the concave mirror 32 can be avoided. In addition, in this case, it is desirable to install a coil as a heat source on the support part side of the concave mirror 32, and to install a magnet as a non-heat source on the concave mirror 32. As the electromagnetic actuator, an electromagnetic actuator using the attraction force of an electromagnet can be applied, and a voice coil type linear motor can also be applied. In the case of using a voice coil type linear motor, the force of other components except the driving direction becomes smaller, which is more suitable. The same is true for the actuator 34 provided on the trapezoidal mirror 31 and the actuator 35 provided on the convex mirror 33. It is preferable to use an electromagnetic actuator or to arrange the heat source away from the optical element. Furthermore, as the actuators 34 to 36 , if a member that is supported in directions other than the driving direction by a bias mechanism is used, a piezoelectric type or a screw feed mechanism may be used.

[0031] In such an exposure device 100, generally speaking, a vibration isolation device (not shown) can be provided to attenuate the disturbance vibration from the installation ground, but it is difficult to eliminate the disturbance vibration using the vibration isolation device. Therefore, during the scanning exposure of the substrate W, the disturbance vibration is sometimes transmitted to various parts of the exposure device 100 (especially the projection optical system 30). In addition, during the scanning exposure of the substrate W, the original plate stage 20 and the substrate stage 40 move, so the vibration generated by the movement is sometimes transmitted to the projection optical system 30. In these cases, the various optical elements (such as the trapezoidal mirror 31, the concave mirror 32, and the convex mirror 33) included in the projection optical system 30 vibrate, which will cause position changes (vibration, image deviation) of the exposure light EL. As a result, it may be difficult to project the pattern image of the original plate M onto the substrate with good accuracy, that is, it is difficult to transfer the pattern of the original plate M onto the substrate with good accuracy. Therefore, the exposure apparatus 100 of the present embodiment includes the measuring unit 50 for measuring the optical characteristics of the projection optical system 30 , and corrects the irradiation position of the exposure light EL on the substrate based on the measurement result of the measuring unit 50 .

[0032] The measuring unit 50 projects the measuring light ML as parallel light (collimated light) into the projection optical system, and measures the optical characteristics of the projection optical system 30, that is, the internal state of the projection optical system 30, based on the measuring light ML that has passed through the optical element in the projection optical system through which the exposed light EL is to pass. Specifically, the measuring unit 50 includes: a light projecting unit 51 that projects the measuring light ML (light beam) into the projection optical system 30; and a light receiving unit 52 that receives the measuring light ML emitted through the projection optical system 30. In the projection optical system 30, the measuring light ML is reflected in the order of the upper surface of the trapezoidal mirror 31, the upper part of the reflecting surface of the concave mirror 32, the convex mirror 33, the lower part of the reflecting surface of the concave mirror 32, and the lower surface of the trapezoidal mirror 31, similarly to the exposed light EL, and is emitted from the projection optical system 30.

[0033] The light projecting unit 51 can include, for example, a light source 51a and a reflector 51b. The light source 51a has a light emitting element such as a gas laser, a semiconductor laser, or an LED, and a collimator lens, and emits the measurement light ML as parallel light (collimated light). The reflector 51b bends the optical path of the measurement light ML emitted from the light source 51a, and guides the measurement light ML into the projection optical system 30. The light projecting unit 51 (light source 51a, reflector 51b) is installed in the projection optical system 30 between the original plate mounting table 20 (original plate M) and the projection optical system 30. In addition, the light projecting unit 51 is configured to make the measurement light ML parallel to the optical axis of the projection optical system 30 by using the reflector 51b disposed between the original plate M and the projection optical system 30. By disposing the reflector 51b on the lower side of the original plate M in this way, the measurement light ML can always be incident on the projection optical system 30.

[0034] The light receiving unit 52 can include, for example, a light receiving element 52a and a reflector 52b. The reflector 52b bends the optical path of the measurement light ML that passes through the projection optical system 30 and is emitted from the projection optical system 30 in front of the substrate W, and guides the measurement light ML to the light receiving element 52a. The light receiving element 52a receives the measurement light ML and outputs a signal value corresponding to the light receiving position of the measurement light ML. In the case of the present embodiment, the light receiving element 52a has a light receiving surface 53 that receives the measurement light ML, and outputs a signal value corresponding to the light receiving position of the measurement light ML at the light receiving surface 53. The specific structure of the light receiving element 52a will be described later. The light receiving unit 52 (light receiving element 52a, reflector 52b) is installed in the projection optical system 30 between the substrate mounting table 40 (substrate W) and the projection optical system 30. In the case of the present embodiment, the projection optical system 30 is a bilateral telecentric optical system, and the measurement light ML is incident parallel to the optical axis of the projection optical system 30, so the measurement light ML is also emitted parallel to the optical axis on the substrate W side of the projection optical system 30. In addition, since parallel light is used as the measurement light ML, the position of the image formation of the projection optical system 30 does not need to be considered with respect to the position of configuring the light receiving element 52a (light receiving surface 53). Therefore, the light receiving element 52a (light receiving surface 53) of the present embodiment can also be configured at a position different from the image formation position of the projection optical system 30.

[0035] Here, when a semiconductor laser or LED is used as the light source 51a of the light projecting unit 51, the measuring light ML can be flashed quickly, so that the measuring light ML having a specific frequency can be emitted. In this case, the noise component can be reduced by synchronizing the output frequency of the signal from the light receiving element 52a of the light receiving unit 52 with the frequency of the measuring light ML emitted from the light source 51a. That is, the signal value of the light receiving element 52a focusing on the specific frequency component can be obtained.

[0036] The measuring section 50 configured as described above can be provided in plurality for the exposure light EL. Figure 2 This is a diagram obtained by observing the projection optical system 30 from above (on the original plate mounting table 20 side), and illustrates the cross section of the exposure light EL (illumination area 11) and the light projection unit 51 (light source 51a, reflector 51b) of the measuring unit 50. A plurality of measuring units 50 can be arranged at a plurality of locations around the exposure light EL so that a plurality of measurement lights ML are projected into the projection optical system 30 respectively. Figure 2In the example shown, four measuring units 50 are provided, and the four measuring units 50 are arranged around the exposure light EL (illumination area 11) in an axisymmetric manner with a straight line that crosses the optical axis (Z-axis direction) of the exposure light EL and is parallel to the scanning direction (X-direction) as an axis. By providing a plurality of measuring units 50 in this way, not only the position change (optical axis deviation) of the measurement light ML in the projection optical system 30 can be measured, but also the magnification component of the projection optical system 30 can be measured.

[0037] It should be noted that the position change of the measuring light ML means that the optical axis of the measuring light ML changes (shifts) from the reference position to the translation direction (XY direction) and the rotation direction (rotation direction around the Z axis) due to passing through the projection optical system 30. In addition, the reference position can be the optical axis position of the measuring light ML to be emitted from the projection optical system 30 according to the incident position to the projection optical system 30.

[0038] Next, a method for measuring the optical characteristics of the projection optical system 30 using the light receiving element 52a of the light receiving unit 52 is described. As the light receiving element 52a, for example, a light intensity sensor (photoelectric conversion sensor) such as a photodiode can be used. In the case of the present embodiment, the light receiving element 52a can include a plurality of photodiodes configured to detect light intensity in each of a plurality of partial regions of the light receiving surface 53. In the following, an example in which the light receiving element 52a uses four photodiodes (also referred to as a four-quadrant photodiode) is described.

[0039] Figure 3 FIG. 5 is a diagram showing a light receiving surface 53 of a light receiving element 52a according to the present embodiment. Figure 1 The YZ plane is shown, but in Figure 3 In order to facilitate the understanding of the description, the case where the light receiving surface 53 is set as the XY plane without using the reflector 52b of the light receiving unit 52 is described. Figure 3 In the example shown, the light receiving element 52a is composed of a four-quadrant photodiode, and the light receiving surface 53 has four partial areas 53a to 53d that can independently detect light intensity. That is, the four-quadrant photodiode as the light receiving element 52a is configured to independently output signal values ​​(for example, current values) corresponding to the light amounts of light incident on the partial areas 53a to 53d respectively. In addition, the signal values ​​(current values) independently output from the four-quadrant photodiode can be connected to a current-voltage converter and converted into voltage values.

[0040] For example, Figure 3Consider the case where the measurement light ML is incident on the center position of the light receiving surface 53 (the center position of the four-quadrant photodiode). In this case, four voltage values ​​A, B, C, and D are obtained from the four-quadrant photodiode. The voltage values ​​A, B, C, and D depend on the light amount of the measurement light EL, the sensitivity of the photodiode, the gain of the current-to-voltage converter, and the like. Moreover, these voltage values ​​change according to the position change of the measurement light EL, and the amount of change depends on the diameter and shape (light amount distribution) of the measurement light EL. For example, if the incident position (light receiving position) of the measurement light EL changes from Figure 3 , the amount of light received in the partial areas 53b to 53c of the light receiving surface 53 increases, and the amount of light received in the partial areas 53a and 53d of the light receiving surface 53 decreases. In other words, the voltage values ​​B and C increase, and the voltage values ​​A and D decrease. On the other hand, if the incident position (light receiving position) of the measuring light EL changes from Figure 3 The light receiving amount in the partial areas 53c to 53d of the light receiving surface 53 increases, and the light receiving amount in the partial areas 53a to 53b of the light receiving surface 53 decreases. In other words, the voltage values ​​C and D increase, and the voltage values ​​A and B decrease.

[0041] Therefore, the control unit 60 can obtain the light receiving position deviation of the measurement light ML based on the central position of the light receiving surface 53 based on the voltage values ​​A to D obtained by the four-quadrant photodiode. The light receiving position deviation of the measurement light ML on the light receiving surface 53 is proportional to the optical axis deviation (X, Y) of the measurement light ML in the projection optical system 30, and can be calculated using the following equations (1) to (2). It should be noted that the above calculation can be performed by the control unit 60 in the present embodiment, but when the measurement unit 50 is provided with a processing unit such as a CPU, it can also be performed by the processing unit.

[0042] X=kx{-(AC)+(BD)}…(1)

[0043] Y=ky{-(AC)-(BD)}…(2)

[0044] The coefficient kx of formula (1) is a conversion coefficient (proportional coefficient) for converting the light receiving position offset (X direction) of the measuring light ML on the light receiving surface 53 into the optical axis offset (X direction) of the measuring light ML in the projection optical system 30. Similarly, the coefficient ky of formula (2) is a conversion coefficient (proportional coefficient) for converting the light receiving position offset (Y direction) of the measuring light ML on the light receiving surface 53 into the optical axis offset (Y direction) of the measuring light ML in the projection optical system 30. The coefficient kx and the coefficient ky can be obtained, for example, by prior experiments, simulations, etc. As an example, by changing the incident position of the measuring light ML to the projection optical system 30 so that the optical axis of the measuring light ML in the projection optical system 30 is offset, the change of the light receiving position offset of the measuring light ML on the light receiving surface 53 is measured successively, so that the coefficient kx and the coefficient ky can be obtained.

[0045] In addition, in the case where the diameter of the measurement light ML is larger than the light receiving surface 53 of the four-quadrant photodiode, or is so small that the width of the joint area (area where the light intensity cannot be detected) of the four-quadrant photodiode cannot be ignored, the voltage values ​​A to D can also be normalized. Specifically, when the sum of the light receiving amounts in the plurality of partial areas 53a to 53d changes due to the light receiving position offset of the measurement light ML on the light receiving surface 53, as shown in the following equations (3) to (4), by normalizing with the sum of the light receiving amounts, it is possible to mainly seek improvement in linearity. It should be noted that the coefficients kx' and ky' of equations (3) to (4) are conversion coefficients (proportional coefficients) for converting the light receiving position offset of the measurement light ML on the light receiving surface 53 into the optical axis offset of the measurement light ML in the projection optical system 30.

[0046] X=kx'{-(AC)+(BD)} / (A+B+C+D)…(3)

[0047] Y=ky'{-(AC)-(BD)} / (A+B+C+D)…(4)

[0048] Here, the measurement light ML passes through a plurality of optical elements through which the exposure light EL passes in the projection optical system 30. Therefore, the optical axis offset of the measurement light ML in the projection optical system 30 obtained by calculating the light receiving position offset of the measurement light ML on the light receiving surface 53 can correspond to the position variation (image deviation) of the exposure light EL on the substrate. That is, by performing the above calculation, the control unit 60 can estimate the position variation of the exposure light EL in the projection optical system 30 based on the light receiving position of the measurement light ML on the light receiving element 52a (light receiving surface 53). Then, the irradiation position of the exposure light EL on the substrate can be corrected according to the estimated position variation of the exposure light EL. In the case of the present embodiment, the irradiation position of the exposure light EL on the substrate can be corrected in parallel with the scanning exposure of the substrate W.

[0049] As described above, in the exposure device 100 of the present embodiment, by using the measurement light ML which is parallel light, a plurality of photodiodes (for example, 4-quadrant photodiodes) can be applied as the light receiving element 52a. That is, in the structure of the present embodiment, compared with the conventional structure in which the projection image of the mark is detected by using an image sensor composed of a light detection element such as a CMOS sensor and a light receiving optical system as described in Patent Document 1, the optical characteristics of the projection optical system 30 can be measured with a simple structure. In addition, in the structure of the present embodiment, since the projection image of the mark is not used in the measurement of the optical characteristics of the projection optical system 30, the light receiving surface 53 of the light receiving element 52a can be arbitrarily arranged without considering the imaging position of the projection optical system 30. That is, the light receiving surface 53 can be arranged at a position different from the imaging position of the projection optical system 30. Therefore, it is advantageous in terms of the device cost and the degree of freedom in design of the device. In addition, in the structure of the present embodiment, the use of photodiodes makes the calculation scale smaller than the conventional structure in which the position of the projection image of the mark is calculated, so the measurement cycle of the optical characteristics of the projection optical system 30 can be shortened. That is, in the conventional configuration, the optical characteristics of the projection optical system 30 are discretely measured, whereas in the configuration of the present embodiment, the optical characteristics of the projection optical system 30 can be continuously measured.

[0050] [Correction of exposure light irradiation position]

[0051] The change in the optical characteristics of the projection optical system 30, that is, the position variation of the exposure light EL in the projection optical system 30 may be caused by, for example, the vibration of the optical elements of the projection optical system 30 and the environmental fluctuation (air fluctuation) in the projection optical system 30. In the case where the position variation of the exposure light EL is caused by the optical elements (trapezoidal mirror 31, concave mirror 32, convex mirror 33) of the projection optical system 30, the control unit 60 corrects the irradiation position of the exposure light EL on the substrate by driving the optical elements by actuators 34 to 36. On the other hand, in the case where the position variation of the exposure light EL is caused by the environmental fluctuation in the projection optical system 30, the control unit 60 corrects the irradiation position of the exposure light EL on the substrate by adjusting the temperature and / or pressure in the projection optical system 30. In the case of the present embodiment, as Figure 1 As shown, an adjustment unit 71 for adjusting the temperature and / or pressure in the projection optical system 30 may be provided.

[0052] An example of a method for correcting the irradiation position of the exposure light EL on the substrate based on the measurement result of the measuring unit 50 is described. As described above, the position variation of the exposure light EL in the projection optical system 30 may be caused by the vibration of the optical elements of the projection optical system 30 and / or the environmental fluctuations in the projection optical system 30. For example, in the plurality of optical elements (such as the trapezoidal mirror 31, the concave mirror 32, and the convex mirror 33) constituting the projection optical system 30, the weights are different from each other, and therefore the natural vibration frequencies (vibration frequencies) are also different from each other. Therefore, as long as the frequency component of the variation (vibration) of the light receiving position of the measurement light ML at the light receiving element 52a is investigated, the optical element that affects the variation of the light receiving position of the measurement light ML, that is, the position variation of the exposure light EL can be determined.

[0053] In the case of the present embodiment, the control unit 60 uses fast Fourier transform or the like to perform frequency analysis (i.e., decompose into a plurality of frequency components) of the variation (vibration) of the light receiving position of the measuring light ML in the light receiving element 52a. Then, when, as a result of the frequency analysis, for example, a frequency component corresponding to the natural vibration frequency of the concave mirror 32 is obtained, the control unit 60 issues a command to the actuator 35 to attenuate (damp) the vibration of the concave mirror 32. As an example, the control unit 60 obtains the command value of the actuator 35 by performing coordinate transformation, gain adjustment, and filtering on the direction and magnitude of the light receiving position deviation of the measuring light ML when the center position of the light receiving element 52a (light receiving surface 53) is used as a reference. By providing the command value obtained in this way to the actuator 35, the vibration of the concave mirror 32 can be reduced. Similarly, when a frequency component corresponding to the natural vibration frequency of the trapezoidal mirror 31 and / or the convex mirror 33 is obtained, the control unit 60 provides a command value to the actuators 34 and 36 to attenuate the vibration of the trapezoidal mirror 31 and / or the convex mirror 33.

[0054] In addition, when a frequency component lower than the natural vibration frequency of each optical element of the projection optical system 30 is obtained as a result of the frequency analysis, the influence of the refractive index variation caused by the environmental fluctuation (temperature, pressure) in the projection optical system 30 is considered. In this case, the control unit 60 can reduce the variation of the light receiving position of the measurement light ML, that is, the position variation of the exposure light EL, by adjusting the temperature and / or pressure in the projection optical system 30 using the adjustment unit 71. For example, the control unit 60 can reduce the position variation of the exposure light EL and correct the irradiation position of the exposure light EL on the substrate by providing the command value of the control parameter for changing the environment in the projection optical system 30 to the adjustment unit 71.

[0055] like Figure 2 As shown in FIG. 1 , in a structure in which a plurality of measuring units 50 are provided, it is possible to partially detect the positional variation of the exposure light EL. In this case, it is possible to selectively correct the irradiation position of the exposure light EL at the portion where the positional variation of the exposure light EL occurs. Figure 2 In the illustrated configuration, not only the translation direction and the rotation direction but also the magnification component of the projection optical system can be measured, so that the actuators 34 to 36 and the adjustment unit 71 can be controlled to correct the magnification component of the projection optical system 30 .

[0056] Here, as described above, the control loop for reducing the vibration of each optical element of the projection optical system 30 based on the detection result in the light receiving element 52a is a position feedback. Therefore, in order to further improve the controllability and stability of the vibration of each optical element, acceleration feedback may be further applied. For example, an acceleration sensor may be provided in each optical element of the projection optical system 30, and acceleration feedback may be further applied based on the acceleration of the optical element detected by the acceleration sensor to reduce the vibration of the optical element. Figure 1 In the example shown, acceleration sensors 37 a to 37 c are provided for each of the plurality of optical elements (the trapezoidal mirror 31 , the concave mirror 32 , and the convex mirror 33 ) in the projection optical system 30 .

[0057] [Estimation of exposure light changes]

[0058] Next, the installation position of the light receiving element 52a in the measuring unit 50 is described. When the optical path length of the exposure light EL from the projection optical system 30 to the substrate W is substantially the same as the optical path length of the measurement light ML from the projection optical system 30 to the light receiving element 52a (light receiving surface 53), the variation (vibration) of the measurement light ML can also be considered to be substantially the same as the variation (vibration) of the exposure light EL. In this case, the control unit 60 can control the actuators 34-36 by considering that the variation (vibration) of the exposure light EL that is substantially the same as the variation (vibration) of the measurement light ML obtained by the light receiving element 52a is generated. However, various structures for exposure are arranged in the area between the projection optical system 30 and the substrate W (substrate mounting table 40), and it is sometimes difficult to arrange the light receiving element 52a at a desired location.

[0059] In the case where the optical path lengths from the projection optical system 30 cannot be configured to be substantially the same for the exposure light EL and the measurement light ML, it is preferable to estimate the variation of the exposure light EL (the deviation of the irradiation position on the substrate) based on the variation of the measurement light ML obtained by the light receiving element 52a (the deviation of the light receiving position). For example, it is assumed that the exposure light EL and the measurement light ML are bent by the same angle due to the vibration of each optical element of the projection optical system 30. In this case, the variation of the measurement light ML on the light receiving element 52a (on the light receiving surface 53) and the variation of the exposure light EL on the substrate may be different due to the difference between the optical path length until the bent measurement light ML reaches the light receiving element 52a and the optical path length until the bent exposure light reaches the substrate W. However, these optical path lengths can be set to be known, so the variation of the measurement light ML on the light receiving element 52a can be converted into the variation of the exposure light EL on the substrate using the ratio of these optical path lengths as a conversion factor.

[0060] Here, the plurality of optical elements (trapezoidal mirror 31, concave mirror 32, convex mirror 33) in the projection optical system 30 are generally arranged at locations where the optical path lengths of the exposure light EL are different from each other. That is, the optical path lengths of the exposure light EL to the substrate W can be different from each other in the plurality of optical elements. Therefore, if the variation of the measurement light ML on the light receiving element 52a is simply converted into the variation of the exposure light EL on the substrate using a conversion coefficient commonly set in the plurality of optical elements, the actual variation of the exposure light EL on the substrate may sometimes produce an error. Therefore, it is preferable to set a conversion coefficient for each optical element.

[0061] In the case of this embodiment, for each optical element, the optical path length to the light receiving element 52a and the optical path length to the substrate W are known, so the conversion coefficient is set for each optical element (each natural frequency) based on these optical path length ratios. The control unit 60 uses fast Fourier transform or the like to convert the time axis data of the variation of the measurement light ML obtained by the light receiving element 52a into frequency axis data, performs frequency analysis, and determines the optical element caused by the vibration of the measurement light ML based on the frequency component obtained from the analysis result. As described above, the plurality of optical elements in the projection optical system 30 have mutually different natural vibration frequencies (vibration frequencies), so it is possible to determine which optical element's vibration causes the vibration of the measurement light ML based on the frequency component obtained from the result of the frequency analysis. Therefore, the control unit 60 can select the conversion coefficient set in association with the determined optical element, and convert the variation of the measurement light ML on the light receiving element 52a into the variation of the exposure light EL on the substrate. As a result, it is possible to reduce the error generated in the actual variation of the exposure light EL on the substrate.

[0062] In addition, in each optical element of the projection optical system 30, there may be a case where the exposure light EL and the measurement light ML are reflected or transmitted at different places, or the wavelengths of the exposure light EL and the measurement light ML are different in order to prevent the resist on the substrate from being photosensitized. In this case, the influence of the vibration of each optical element may be different for the exposure light EL and the measurement light ML, so errors may sometimes occur when converting the variation of the measurement light ML on the light receiving element 52a to the variation of the exposure light EL on the substrate. Therefore, it is preferable to obtain the difference in the influence of the vibration of each optical element on the exposure light EL and the measurement light ML (hereinafter sometimes referred to as "influence difference") through experiments, simulations, etc., and correct the conversion coefficient to reduce the difference. For example, using a conversion coefficient set in advance, the variation of the measurement light ML on the light receiving element 52a is converted into the variation of the exposure light EL on the substrate, and based on the obtained variation of the exposure light EL, the scanning exposure of the substrate W is performed while correcting the irradiation position of the exposure light EL on the substrate. If the pattern actually formed on the substrate by the scanning exposure has errors such as image deviation and exposure unevenness (for example, overlap error with the base pattern), the error can be equivalent to the difference in influence between the exposure light EL and the measurement light ML. Therefore, the conversion factor can be corrected to reduce the error.

[0063] As described above, the variation of the measurement light ML on the light receiving element 52a is sometimes caused by environmental fluctuations (air fluctuations) in the projection optical system 30. The measurement light ML and the exposure light EL pass through the same space in the projection optical system 30, so the measurement light ML is affected by the environmental fluctuations that are substantially the same as those of the exposure light EL. Therefore, based on the variation of the measurement light ML on the light receiving element 52a, the variation of the exposure light EL on the substrate caused by the environmental fluctuations in the projection optical system 30 can be estimated.

[0064] For example, in the result of frequency analysis of the variation of the measurement light ML on the light receiving element 52a, at least a part of the frequencies other than the natural vibration frequency of the optical elements of the projection optical system 30 can be regarded as the influence caused by the environmental fluctuation in the projection optical system 30. The control unit 60 can correct the variation of the exposure light EL caused by the environmental fluctuation by adjusting the temperature and / or pressure in the projection optical system 30 by the adjustment unit 71, or can correct it by driving the optical elements of the projection optical system 30 by the actuators 34 to 36. It should be noted that the measurement unit 50 of this embodiment can also be used as a sensor for monitoring the influence of the environmental fluctuation in the projection optical system 30 on the exposure light EL during scanning exposure. Therefore, it can also be effectively used in the development of hardware and device driver software for reducing the environmental fluctuation.

[0065] [Methods to improve measurement accuracy]

[0066] In order to improve the measurement accuracy of the variation of the measurement light ML in the measurement unit 50 and to more accurately correct the irradiation position of the exposure light EL on the substrate, it is preferable to improve the detection resolution of the measurement light ML in the light receiving element 52a. Several methods for improving the detection resolution are described below.

[0067] As a first method, it is to reduce noise as much as possible. In the signal value output from the light receiving element 52a, in addition to the original signal value based on the measurement light ML, it also includes noise components caused by interference light other than the measurement light ML, electrical noise components generated by the current-voltage converter, etc. Therefore, if these noise components are reduced as much as possible, the S / N ratio can be improved and the detection resolution can be improved. As a method for reducing interference light, there is a method of shading the periphery of the light receiving element 52a, or using a wavelength filter to block interference light other than the measurement light ML. In addition, as a method for reducing electrical noise components, there is a method of making the current-voltage converter used as low-noise as possible, or shielding the periphery of the light receiving element 52a from the surrounding electromagnetic field. In addition, the noise and gain of the current-voltage converter are related to each other, so it is better to consider both and set it.

[0068] As a second method, the diameter of the measurement light ML incident on the light receiving element 52a is reduced as much as possible. The smaller the diameter of the measurement light ML, the sharper the light quantity distribution becomes. Therefore, even if the amount of change of the measurement light ML is the same, the signal value obtained by the four-quadrant photodiode (each partial area 53a to 53d) can be changed to a large extent. This means that the sensitivity is improved, and since the signal side of the S / N ratio is improved, smaller position changes can be detected.

[0069] As a third method, there is a method of adjusting the light intensity (light amount) of the measurement light ML so that the voltage values ​​A to D output from the light receiving element 52a (four-quadrant photodiode) are close to the maximum output of the current-voltage converter. This also has the effect of increasing the voltage change (signal) of the light receiving element 52a caused by the position change of the measurement light ML, so the sensitivity of the light receiving element 52a can be improved. For example, by setting the light intensity (light amount) of the measurement light ML output from the light source 51a to be greater than the required light intensity, changing the transmittance of the ND filter arranged between the light source 51a and the light receiving element 52a, the light intensity of the measurement light ML can be adjusted.

[0070] As a fourth method, there is a method of measuring a tiny voltage by using a high-resolution measurement system. Alternatively, by using an action amplifier to amplify the signals (AC) and (BD) in the above equations (1) to (4), it is possible to measure the tiny voltage components included in the voltage values ​​A, B, C, and D output from the light receiving element 52a, and it is also possible to seek to improve the resolution.

[0071] However, generally speaking, the output of the action amplifier is limited, so it is better to set the absolute values ​​of the differential components (AC) and (BD) as small as possible and the average voltages of the voltage values ​​A, B, C, and D to be the same. For example, when a differential amplifier with a maximum output of 10 [V] is used, when the average value of the voltage value A is 8 [V] and the average value of the voltage value C is 7 [V], the maximum gain of the differential amplifier can only be 10 times. On the other hand, when the average value of the voltage value A is 8.0 [V] and the average value of the voltage value C is 7.9 [V], the maximum gain of the action amplifier can be 100 times, so that even smaller voltage components can be amplified and detected.

[0072] In order to be able to adjust the average voltage level of each of the above-mentioned voltage values ​​A, B, C, and D in the same manner, it is preferable to make the light intensity distribution of the measurement light ML symmetrical with respect to the optical axis. In addition, it is preferable to have a mechanism for adjusting the relative position of the measurement light ML and the light receiving element 52a. In the light receiving element 52a, the position relative to the projection optical system 30 may change due to thermal deformation of its fixing part, etc. Therefore, it is preferable to set an adjustment mechanism for adjusting the position and / or posture of the light receiving element 52a relative to the projection optical system 30 in the exposure device 100 in the surface direction orthogonal to the optical axis of the received measurement light ML (two orthogonal directions).

[0073] In the measuring unit 50, the emission direction and emission position of the measuring light ML may change for the light source 51a of the light projecting unit 51. In addition, similarly to the light receiving element 52a, the emission direction and emission position of the measuring light ML may change for the light source 51a due to the thermal deformation of its fixing part. As described above, if the emission direction and emission position of the measuring light ML change in the light source 51a, it may be difficult to make the measuring light ML incident on the projection optical system 30 at a desired incident angle and incident position. As a result, the variation of the exposure light EL on the substrate converted from the variation of the measuring light ML on the light receiving element 52a may cause an error caused by the measuring unit 50 itself. Therefore, it is preferable to provide the exposure device 100 with an adjustment mechanism for adjusting the position and / or posture of the light source 51a relative to the projection optical system 30 to change the position and / or inclination of the measuring light ML emitted from the light source 51a.

[0074] It should be noted that, during the process of adjusting the position and posture of the light source 51a and / or the light receiving element 52a, the variation of the measurement light ML cannot be measured. Therefore, it is preferred that the position and posture of the light source 51a and / or the light receiving element 52a are not adjusted during the scanning exposure of the substrate W, but are adjusted in a process other than scanning exposure, such as during the replacement process of the master M and the substrate W, or during the alignment process of the master M and the substrate W.

[0075] Here, in the present embodiment, the projection optical system 30 is described as a reflective optical system, but it may be a refractive optical system or a reflective refractive optical system. Figure 2The shape of the illumination area 11 (cross section of the exposure light EL) shown may differ depending on the optical system to be applied, but by configuring the reflector 51b around the illumination area 11 (periphery), the same effect as configuring the light source 51a near the illumination area 11 can be obtained. In addition, in the present embodiment, a four-quadrant photodiode is used as the light receiving element 52a, but a plurality of non-quadrant (divided) type photodiodes may be used, and optical division may be performed using a prism or a beam splitter. Moreover, in the present embodiment, an example of configuring a plurality of measuring units 50 (light receiving elements 52a) is described, but only one measuring unit 50 (light receiving element 52a) may be configured to measure only the amount of change of the measurement light ML in the translation direction.

[0076] <Second Embodiment>

[0077] The second embodiment of the present invention is described. This embodiment is basically a successor to the first embodiment, so the following describes the differences from the first embodiment. In the first embodiment, the irradiation position of the exposure light EL on the substrate is corrected by driving the optical elements of the projection optical system 30 using the actuators 34 to 36 and / or by adjusting the environment (temperature, pressure) in the projection optical system 30 using the adjustment unit 71. In this embodiment, an example of correcting the irradiation position of the exposure light EL on the substrate by changing the relative position of the original plate M and the substrate W is described.

[0078] In the case of this embodiment, the control unit 60 estimates the variation of the exposure light EL on the substrate based on the variation of the measurement light ML on the light receiving element 52a. Specifically, the variation of the measurement light ML on the light receiving element 52a is converted into the variation of the exposure light EL on the substrate using a conversion factor set in advance. Then, the control unit 60 drives the substrate stage 40 and controls (adjusts) the position of the substrate W to correct the estimated variation of the exposure light EL.

[0079] For example, the signal value output from the light receiving element 52a is averaged, or the rotation component is extracted and the illumination area 11 is moved and averaged, and coordinate transformation, gain adjustment, filtering, etc. are performed at the same time, so as to obtain a command value for correcting the variation of the light EL of exposure. Then, the obtained command value is added to the command value for scanning the substrate W and supplied to the substrate stage 40. In this way, when the variation of the light EL of exposure is corrected by driving the substrate stage 40, the actuators 34 to 36 for driving the optical elements of the projection optical system 30 may not be provided, so that the device structure can be simplified. In addition, in the present embodiment, a structure in which the command value for correcting the variation of the light EL of exposure is supplied to the substrate stage 40 is described, but a structure in which the command value for correcting the variation of the light EL of exposure may also be supplied to the original plate stage 20. In addition, the variation of the light EL of exposure may be corrected by driving the substrate stage 40 and the original plate stage 20 in a relative manner. Moreover, in the case where a driving mechanism for driving the projection optical system 30 is provided, the variation of the light EL of exposure may also be corrected by driving the projection optical system 30.

[0080] <Third Embodiment>

[0081] A third embodiment of the present invention will be described. This embodiment is basically a successor to the first embodiment and / or the second embodiment, and therefore, the differences from these embodiments will be described below.

[0082] In the measuring unit 50, the emission direction and emission position of the measuring light ML sometimes change for the light projecting unit 51 (light source 51a). In this way, if the emission direction and emission position of the measuring light ML change in the light projecting unit 51 (i.e., deviate from the target emission direction / position), it is difficult to make the measuring light ML incident on the projection optical system 30 at the desired incident angle and incident position. As a result, the variation of the exposure light EL on the substrate converted from the variation of the measuring light ML on the light receiving element 52a may produce an error caused by the measuring unit 50 itself. This error is a measurement error component that is not generated in the exposure light EL. Therefore, if the variation of the exposure light EL on the substrate is estimated based on the light receiving result of the light receiving element 52a caused by this error, and the irradiation position of the exposure light EL on the substrate is corrected based on the variation of the exposure light EL, the imaging performance will be reduced, such as contrast reduction and image deviation.

[0083] Therefore, the measuring unit 50 of the present embodiment includes a detection unit 54 for detecting at least one of the emission angle and the emission position (hereinafter sometimes referred to as "emission angle, etc.") of the light beam emitted from the light projecting unit 51 (light source 51a). That is, the detection unit 54 can be configured to detect at least one of the incident angle and the incident position (hereinafter sometimes referred to as "incident angle, etc.") of the measurement light ML incident on the projection optical system 30 as the offset position variation of the measurement light ML caused by the measuring unit 50. In addition, in the case of the present embodiment, the control unit 60 corrects the variation of the measurement light ML on the light receiving element 52a based on the offset position variation detected by the detection unit 54, and can estimate the variation of the exposure light EL on the substrate based on the value obtained thereby.

[0084] Figure 4 1 is a schematic diagram showing the structure of the exposure device 300 of the third embodiment. The exposure device 300 of this embodiment is different from the exposure device 100 of the first embodiment in that a detection unit 54 is provided in the measurement unit 50. The structure other than this is the same as that of the exposure device 100 of the first embodiment, and therefore the description thereof is omitted.

[0085] The detection unit 54 is provided outside the projection optical system 30, and can include, for example, a beam splitter 54a (second branching unit), a light receiving element 54b (second light receiving element), a light receiving element 54c (third light receiving element), and a reflector 54d. The components of the detection unit 54 (beam splitter 54a, light receiving elements 54b, 54c, reflector 54d) are relatively fixed to the projection optical system 30, and are preferably mounted on the projection optical system 30. In addition, in the structure of the measurement unit 50 of the present embodiment, a beam splitter 55 (branching unit) is provided instead of the reflector 51b of the light projecting unit 51.

[0086] The light beam emitted from the light source 51a of the light projecting unit 51 is branched into two light beams by the beam splitter 55. One of the two light beams branched by the beam splitter 55 is guided into the projection optical system 30 as the measurement light ML, and the other light beam is guided to the detection unit 54 (beam splitter 54a) as the detection light DL for detecting the incident angle of the measurement light ML. The detection light DL guided to the detection unit 54 is branched into two light beams by the beam splitter 54a, one light beam (first detection light DL1) is guided to the light receiving element 54b via the reflector 54d, and the other light beam (second detection light DL2) is guided to the light receiving element 54c. Here, the light receiving elements 54b and 54c are, for example, the same structure as the light receiving element 52a of the light receiving unit 52, and can be composed of a four-quadrant photodiode. Therefore, the method of calculating the variation of the detection light DL on the light receiving surface in each light receiving element 54b, 54c is the same as the method of calculating the variation of the measurement light ML on the light receiving surface 53 in the light receiving element 52a of the light receiving unit 52 (described in the first embodiment).

[0087] The optical path length of the first detection light DL1 received by the light receiving element 54b and the optical path length of the second detection light DL2 received by the light receiving element 54c are set to known and different lengths. If the optical path lengths of the first detection light DL1 and the second detection light DL2 are made different in this way, the variation of the first detection light DL on the light receiving surface of the light receiving element 54b and the variation of the second detection light DL on the light receiving surface of the light receiving element 54c are different. Therefore, the control unit 60 can detect the emission angle of the light beam emitted from the light projecting unit 51 (light source 51a) based on the difference between the variation of the first detection light DL obtained by the light receiving element 54b and the variation of the second detection light DL obtained by the light receiving element 54d. In addition, the positional relationship between the light projecting unit 51 (light source 51a), the beam splitter 55 and the projection optical system 30 is known, so the incident angle of the measurement light ML to the projection optical system 30 can be obtained as the offset position variation based on the emission angle.

[0088] On the other hand, the measurement light ML that has passed through the projection optical system 30 is received by the light receiving element 52a (light receiving surface 53) of the light receiving unit 52. The variation of the measurement light ML obtained by the light receiving element 52a can include a component caused by the vibration of each optical element of the projection optical system 30, a component caused by environmental fluctuations in the projection optical system 30, and a component caused by the measurement unit 50 itself, such as an error in the incident angle of the measurement light ML to the projection optical system 30. In the case of the present embodiment, the control unit 60 removes the offset position variation detected by the detection unit 54 from the variation of the measurement light ML on the light receiving element 52a, and estimates the variation of the exposure light EL on the substrate based on the value obtained thereby. In this way, the variation of the exposure light EL on the substrate is estimated based on the value obtained by removing the offset position variation caused by the measurement unit 50 itself, so that the irradiation position of the exposure light EL on the substrate can be corrected with good accuracy.

[0089] <Fourth Implementation Method>

[0090] A fourth embodiment of the present invention will be described. In this embodiment, a modification of the third embodiment in which a detector 54 for detecting the offset position variation is provided in a measuring unit 50 will be described. This embodiment is basically a successor to the third embodiment, and therefore the differences from the third embodiment will be described below.

[0091] Figure 5 1 is a schematic diagram showing the structure of the exposure device 400 of the fourth embodiment. Compared with the exposure device 300 of the third embodiment, the exposure device 400 of the present embodiment has the light receiving element 54c deleted from the measuring unit 50 (detection unit 54). That is, the detection unit 54 of the present embodiment is composed of the light receiving element 54b (second light receiving element).

[0092] The light beam emitted from the light source 51a of the light projecting unit 51 is branched into two light beams by the beam splitter 55. One of the two light beams branched by the beam splitter 55 is guided into the projection optical system 30 as the measurement light ML, and the other light beam is guided to the light receiving element 54b as the detection light DL for detecting the incident angle of the measurement light ML. Here, the measuring unit 50 of the present embodiment is configured so that the optical path length of the detection light DL received by the light receiving element 54b is substantially the same as the optical path length of the measurement light ML received by the light receiving element 52a of the light receiving unit 52. For example, the detection light DL is deflected by a plurality of reflective mirrors in a manner substantially the same as the optical path length of the measurement light ML and is received by the light receiving element 54b.

[0093] Specifically, the detection unit 54 is configured in such a manner that the optical path of the measuring light ML is substantially the same as the optical path of the detection light DL. The optical path length of the measuring light ML passes through a plurality of optical elements of the projection optical system 30, and therefore it is not realistic to connect the optical path of the detection light DL into a straight line within the device. Therefore, it is preferred to use optical elements such as bending mirrors and reflectors to obtain the optical path length in a limited space. In addition, it is preferred that the optical elements for expanding these optical path lengths are relatively fixed to the projection optical system 30, and it is preferred that they are installed in the projection optical system 30. Thus, the measurement light deviation can be measured using the projection optical system 30 alone, and thus it can be used for unit inspection of a projection optical system unit alone before assembling the exposure device.

[0094] In such a structure, assuming that no vibration or environmental fluctuation occurs in each optical element in the projection optical system 30, the variation of the measurement light ML on the light receiving element 52a and the variation of the detection light DL on the light receiving element 54b may be the same. That is, the difference between the variation of the measurement light ML obtained by the light receiving element 52a and the variation of the detection light DL obtained by the light receiving element 54b is a component caused by the vibration or environmental fluctuation of each optical element in the projection optical system 30. Therefore, the control unit 60 can estimate the variation of the exposure light EL on the substrate based on the value obtained by subtracting the variation of the detection light DL on the light receiving element 54 from the variation of the measurement light ML on the light receiving element 52a.

[0095] Here, the optical path length being substantially the same refers to a range of such a degree that even if there is a change in the measuring light ML or the detection light DL (e.g., a change in the inclination), the resulting change in the light receiving position on the light receiving element can be considered substantially the same. This varies depending on the application, and the range varies depending on the measurement accuracy (resolution) of the position change as the target, the angle of emission of the light beam from the light source 51a, and the like. For example, in the case where the inclination change of the measuring light ML caused by the light source 51a and its fixing system is about 10 μrad and the measurement error based on the optical path length error is set to be less than 10 nm, the optical path length error needs to be suppressed to about 1 mm. In this case, the substantially same optical path length is equivalent to a difference in the optical path length of less than 1 mm. On the other hand, in the case where the measurement error based on the optical path length error is allowed to be as large as about 1 μm, the optical path length error can also be about 100 mm. In this case, for substantially the same optical path length, the optical path length difference can also be less than 100 mm, and even if the optical path length difference is larger than the previous example, it can be considered substantially the same.

[0096] <Fifth Implementation Method>

[0097] A fifth embodiment of the present invention will be described. In this embodiment, exposure processing performed by the exposure apparatus described in the first to fourth embodiments will be described. Figure 6 is a flowchart showing the exposure process. Figure 6 Each step of the flowchart shown can be controlled by the control unit 60 .

[0098] In S1, the control unit 60 uses a substrate conveying mechanism (not shown) to convey the substrate W onto the substrate stage 40, so that the substrate stage 40 holds the substrate W. In S2, the control unit 60 performs a global alignment process. For example, the control unit 60 uses an alignment observer (not shown) to measure the position of the alignment mark of the sample shot region formed in the plurality of shot regions of the substrate W, and obtains the arrangement information of the plurality of shot regions by statistically processing the measurement results.

[0099] In S3, the control unit 60 sequentially performs scanning exposure on each of the plurality of irradiation areas, and transfers the pattern of the original plate M to each irradiation area (specifically, the photosensitive material (resist) thereon) as a latent image pattern. In the scanning exposure of each irradiation area in S3, as described in the first to fourth embodiments above, the optical characteristics of the projection optical system 30 are measured by the measuring unit 50, and the irradiation position of the exposure light EL on the substrate is corrected based on the measurement result. That is, in the scanning exposure of each irradiation area, the irradiation position of the exposure light EL can be corrected in real time based on the measurement result of the measuring unit 50.

[0100] In S4, the control unit 60 uses a substrate conveying mechanism (not shown) to unload the substrate W from the substrate mounting table 40. In S5, the control unit 60 determines whether there is a next substrate to be subjected to scanning exposure. If there is a next substrate, the process returns to S1 and performs scanning exposure on the next substrate. On the other hand, if there is no next substrate, the process ends.

[0101] <Implementation Method of Manufacturing Article>

[0102] The method for manufacturing an article according to an embodiment of the present invention is suitable for manufacturing micro devices such as semiconductor devices, components with fine structures and other articles. The method for manufacturing an article according to the present embodiment includes: a process of forming a latent image pattern on a photosensitive agent coated on a substrate using the above-mentioned exposure device (a process of exposing the substrate); and a process of developing (processing) the substrate on which the latent image pattern is formed in the process. In addition, the manufacturing method includes other well-known processes (oxidation, film formation, evaporation, doping, planarization, etching, resist stripping, cutting, bonding, packaging, etc.). Compared with previous methods, the method for manufacturing an article according to the present embodiment is advantageous in at least one of the performance, quality, productivity and production cost of the article.

[0103] (Other embodiments)

[0104] The present invention can also be implemented by supplying a program that implements one or more functions of the above-mentioned embodiments to a system or device via a network or storage medium, and one or more processors in a computer of the system or device read out and execute the program. In addition, it can also be implemented by a circuit (e.g., ASIC) that implements one or more functions.

[0105] Other embodiments

[0106] The embodiments of the present invention may also be implemented by providing software (program) for performing the functions of the above-described embodiments to a system or device via a network or various storage media, and a computer or a central processing unit (CPU) or a microprocessing unit (MPU) of the system or device reads and executes the program.

[0107] The present invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, in order to disclose the scope of the invention, the following claims are attached.

Claims

1. An exposure device for exposing a substrate, the exposure device comprising: A projection optical system, comprising a plurality of optical elements, projects the pattern image of the original onto the substrate using exposure light; a measuring unit that measures an optical characteristic of the projection optical system using a measurement light emitted from the projection optical system via an optical element of the projection optical system; as well as a control unit that corrects an irradiation position of the exposure light on the substrate based on a measurement result of the measurement unit, The measuring unit includes a light receiving element for receiving the measuring light. The control unit determines the optical element that affects the position variation of the exposure light from among the multiple optical elements based on the frequency component of the position variation of the measurement light on the light receiving element, and corrects the irradiation position of the exposure light on the substrate by driving the determined optical element.

2. An exposure device for exposing a substrate, the exposure device comprising: A projection optical system projects the pattern image of the original plate onto the substrate using exposure light; a measuring unit that measures an optical characteristic of the projection optical system using a measurement light emitted from the projection optical system via an optical element of the projection optical system; as well as a control unit that corrects an irradiation position of the exposure light on the substrate based on a measurement result of the measurement unit, The measuring unit includes a light receiving element for receiving the measuring light. When the control unit determines that environmental fluctuations in the projection optical system affect position variations of the exposure light based on a frequency component of position variations of the measurement light on the light receiving element, the control unit corrects the irradiation position of the exposure light on the substrate by adjusting the environment in the projection optical system.

3. The exposure device according to claim 1, characterized in that The light receiving element is mounted on the projection optical system.

4. The exposure device according to claim 1, characterized in that The light receiving element has a light receiving surface for receiving the measurement light. The light receiving surface is arranged at a position different from an image forming position of the projection optical system.

5. The exposure device according to claim 1, characterized in that The measuring unit further includes a light projecting unit that projects the measuring light into the projection optical system. The light projecting unit is mounted on the projection optical system.

6. The exposure device according to claim 5, characterized in that The light projecting unit projects the measuring light in parallel with the optical axis of the projection optical system.

7. The exposure device according to claim 5, characterized in that The light projecting unit is arranged between the original plate and the projection optical system.

8. The exposure device according to claim 1, characterized in that The projection optical system is composed of two-side telecentric optical systems.

9. The exposure device according to claim 1, characterized in that The light receiving element includes a photodiode.

10. The exposure device according to claim 1, characterized in that The control unit estimates a positional variation of the exposure light in the projection optical system based on a light receiving position of the measurement light on the light receiving element, and corrects an irradiation position of the exposure light on the substrate according to the estimated positional variation of the exposure light.

11. The exposure device according to claim 10, characterized in that The measuring unit further includes a detecting unit configured to detect at least one of an incident angle and an incident position of the measuring light into the projection optical system. The control unit further estimates a positional variation of the exposure light within the projection optical system based on the detection result of the detection unit.

12. The exposure device according to claim 11, characterized in that The detection unit includes: a branching unit that branches a portion of the measurement light before being projected into the projection optical system as detection light; and a second light receiving element that receives the detection light without passing through the projection optical system, wherein the detection unit detects at least one of an incident position and an incident angle of the measurement light into the projection optical system based on a light receiving position of the detection light on the second light receiving element.

13. The exposure device according to claim 12, characterized in that: The second light receiving element is arranged so that the optical path length of the detection light is the same as the optical path length of the measurement light. The control unit estimates the position variation of the exposure light in the projection optical system based on a difference between the position variation of the measurement light on the light receiving element and the position variation of the detection light on the second light receiving element.

14. The exposure device according to claim 12, characterized in that: The detection unit further includes: a second branching unit that branches the detection light into the first detection light and the second detection light; and a third light receiving element that receives the second detection light without passing through the projection optical system. The second light receiving element receives the first detection light. The control unit corrects the position variation of the measuring light on the light receiving element based on the difference between the position variation of the first detection light on the second light receiving element and the position variation of the second detection light on the third light receiving element, and estimates the position variation of the exposure light in the projection optical system based on the value obtained.

15. The exposure device according to claim 14, characterized in that An optical path length of the first detection light received by the second light receiving element and an optical path length of the second detection light received by the third light receiving element are different from each other.

16. An exposure device for exposing a substrate, the exposure device comprising: A projection optical system projects the pattern image of the original plate onto the substrate using exposure light; a measurement light source that is different from an exposure light source that emits the exposure light; a measuring unit that measures optical characteristics of the projection optical system using measurement light emitted from a measurement light source via an optical element of the projection optical system; and a control unit that estimates a positional change in a position where the exposure light is irradiated on the substrate based on a result measured by the measuring unit, The measuring unit includes a light receiving element for receiving the measuring light. The light receiving element receives the measuring light as parallel light.

17. The exposure device according to claim 16, characterized in that: The light receiving element has a light receiving surface for receiving the measurement light. The light receiving surface is arranged at a position different from an image forming position where the pattern image of the original plate is formed via the projection optical system.

18. The exposure device according to claim 16, characterized in that The light receiving element and the measuring light source are mounted on the projection optical system.

19. A method for manufacturing an article, characterized in that include: A step of exposing a substrate using the exposure apparatus according to any one of claims 1 to 18; as well as developing the substrate exposed in the above steps, An article is manufactured from the developed substrate.

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