JP7453790B2 - Exposure device and article manufacturing method - Google Patents

Description

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

In a lithography process, which is one of the manufacturing processes for semiconductor devices, liquid crystal displays, etc., an exposure apparatus is used that exposes a substrate by projecting a pattern image of an original onto the substrate via a projection optical system. With the miniaturization of semiconductor devices, for example, exposure equipment is required to accurately transfer the pattern of the original onto the substrate, but changes in the optical characteristics of the projection optical system during exposure of the substrate affect the transfer accuracy. This could be one factor that causes the decline. Changes in the optical characteristics of the projection optical system can be caused by, for example, vibrations of optical elements included in the projection optical system, temperature changes and pressure changes within the projection optical system. Patent Document 1 discloses that a measurement mark is placed near the original, and the optical characteristics of the projection optical system are determined based on the position of the projection image obtained by receiving the projection image of the measurement mark by the projection optical system with a light receiving section. A configuration for correcting (imaging performance) is disclosed.

JP2017-72678A

In the configuration described in Patent Document 1, the measurement mark is provided on a member fixed to the main body of the exposure apparatus, and the light receiving section that receives the projected image of the measurement mark is attached to the same structure as the measurement mark (exposure (main body of the device). In other words, the projection optical system and the light receiving section are provided apart from each other. However, in such a configuration, the relative position between the projection optical system and the light receiving section may fluctuate, so the optical characteristics of the projection optical system are accurately determined based on the reception result of the projected image of the measurement mark by the light receiving section. Can be difficult to measure.

Therefore, an object of the present invention is to provide an advantageous technique for accurately measuring the optical characteristics of a projection optical system.

In order to achieve the above object, an exposure apparatus as one aspect of the present invention is an exposure apparatus that exposes a substrate, includes a plurality of optical elements, and projects a pattern image of an original onto the substrate using exposure light. an optical system; a measurement unit that measures 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 passes; a control unit that corrects the irradiation position of the exposure light on the substrate based on the measurement result in the measurement unit, the measurement unit includes a light receiving element that receives the measurement light, and the control unit identifies and identifies an optical element that is affecting the positional fluctuation of the exposure light from among the plurality of optical elements based on the frequency component of the positional fluctuation of the measurement light on the light receiving element. The method is characterized in that the irradiation position of the exposure light on the substrate is corrected by driving an optical element .

Further objects or other aspects of the invention will become apparent from the preferred embodiments described below with reference to the accompanying drawings.

According to the present invention, for example, it is possible to provide an advantageous technique for accurately measuring the optical characteristics of a projection optical system.

Schematic diagram showing the configuration of an exposure apparatus according to the first embodiment Diagram of the projection optical system viewed from above (original stage side) Diagram showing the light-receiving surface of the light-receiving element Schematic diagram showing the configuration of an exposure apparatus according to the third embodiment Schematic diagram showing the configuration of an exposure apparatus according to the fourth embodiment Flowchart showing the exposure process

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the claimed invention. Although a plurality of features are described in the embodiments, not all of these features are essential to the invention, and the plurality of features may be arbitrarily combined. Furthermore, in the accompanying drawings, the same or similar components are designated by the same reference numerals, and redundant description will be omitted.

<First embodiment>
An exposure apparatus 100 according to a first embodiment of the present invention will be described. Exposure apparatus 100 is a lithography apparatus used for manufacturing semiconductor devices, liquid crystal displays, and the like. The exposure apparatus 100 of this embodiment is a projection exposure apparatus that exposes the substrate by projecting a pattern image of an original (mask, reticle) onto the substrate using a stepper method or a scanning method, and transfers the pattern of the original onto the substrate. . Below, as the exposure apparatus 100, a scanning type exposure apparatus that scans and exposes a substrate using slit light will be exemplified and explained.

[Exposure device configuration]
FIG. 1 is a schematic diagram showing the configuration of an exposure apparatus 100 according to the first embodiment. The exposure apparatus 100 of this embodiment includes an illumination optical system 10, an original stage 20 that is movable while holding an original M, a projection optical system 30, a substrate stage 40 that is movable while holding a substrate W, and a measurement The control unit 50 may include a control unit 50 and a control unit 60. The control unit 60 is configured by, for example, a computer having a CPU, a memory, etc., and controls the exposure processing of the substrate W (each part of the exposure apparatus 100). The original M is a glass original in which a fine pattern (for example, a circuit pattern) to be transferred onto the substrate W is formed of a light-shielding material such as chromium. Further, as the substrate W, a semiconductor wafer, a glass plate, or the like may be used.

The illumination optical system 10 shapes light from a 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 obtain a desired illuminance distribution on the original. The original M is illuminated with substantially uniform illuminance. A mercury lamp or the like can be used as a light source. The original M and the substrate W are held by an original stage 20 and a substrate stage 40, respectively, and are moved to an almost optically conjugate position (the position of the object plane and image plane of the projection optical system 30) via the projection optical system 30. Placed. The projection optical system 30 has a predetermined projection magnification, and projects the pattern image of the mask 1 onto the substrate 2 by reflecting it with a plurality of mirrors. Then, the mask stage 20 and the substrate stage 40 are relatively synchronously scanned in 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, the substrate W can be scanned and exposed, and the pattern formed on the original M can be transferred to the substrate W (specifically, the resist (photosensitive agent) on the substrate).

The projection optical system 30 may be configured to include, for example, a trapezoidal mirror 31, a concave mirror 32, and a convex mirror 33, as shown in FIG. The pattern light EL (hereinafter sometimes referred to as "exposure light EL") that is emitted from the illumination optical system 10 and passes through the original M has its optical path bent by the upper surface of the trapezoidal mirror 31 and is reflected by the reflective surface of the concave mirror 32. Inject at the top. The exposure light EL reflected on the upper part of the reflective surface of the concave mirror 32 is reflected on the reflective surface of the convex mirror 33 and enters the lower part of the reflective surface of the concave mirror 32. The exposure light EL reflected at the lower part of the reflective surface of the concave mirror 32 has its optical path bent by the lower surface of the trapezoidal mirror 31 and enters the substrate W. In the projection optical system 30 configured in this way, the reflective surface of the convex mirror 33 serves as an optical pupil. In addition, the projection optical system 30 is configured such that both the original M side and the substrate W side, that is, the object plane side and the image plane side, do not cause magnification errors due to positional fluctuations in the optical axis direction (Z direction) of the original M and substrate W. It has a telecentric optical system.

Further, the projection optical system 30 may be provided with an actuator for driving each optical element. 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 34-36 may be used to reduce fluctuations (vibration) of each optical element.

Here, it is preferable that the actuators 35 are arranged at at least three locations with respect to the concave mirror 32. As the actuator 35, an actuator such as an electromagnetic actuator in which a fixed part and a movable part are configured in a non-contact manner can be used. In this case, deformation of the concave mirror 32 into the concave mirror 32 due to interference of the support part of the concave mirror 32 can be avoided. can do. Further, in this case, it is desirable to attach a coil serving as a heat source to the support portion side of the concave mirror 32 and a magnet serving as a non-heat source to the concave mirror 32. As the electromagnetic actuator, one using the attractive force of an electromagnet may be used, or a voice coil type linear motor may be used. When using a voice coil type linear motor, the force of components other than the driving direction is reduced, so it is more suitable. The same applies to the actuator 34 provided on the trapezoidal mirror 31 and the actuator 35 provided on the convex mirror 33, and it is preferable to use an electromagnetic actuator or to place the heat source away from the optical element. Further, as the actuators 34 to 36, it is also possible to use a piezoelectric type or a screw feeding mechanism as long as a means for supporting the actuators in a direction other than the driving direction is supported by a dodging mechanism.

Such an exposure apparatus 100 may generally be provided with a vibration isolator (not shown) that damps disturbance vibrations from the installation floor, but it is difficult to eliminate disturbance vibrations with the vibration isolator. Therefore, during scanning exposure of the substrate W, disturbance vibrations may be transmitted to each part of the exposure apparatus 100 (especially the projection optical system 30). Furthermore, since the original stage 20 and the substrate stage 40 move during scanning exposure of the substrate W, vibrations caused by the movement may be transmitted to the projection optical system 30. In these cases, each optical element included in the projection optical system 30 (for example, the trapezoidal mirror 31, the concave mirror 32, and the convex mirror 33) vibrates, and the positional variation (vibration, image shift) of the exposure light EL may occur. As a result, it may become difficult to accurately project the pattern image of the original M onto the substrate, that is, to accurately transfer the pattern of the original M onto the substrate. Therefore, the exposure apparatus 100 of the present embodiment includes a measuring section 50 that measures 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 results in the measuring section 50. do.

The measurement unit 50 projects measurement light ML as parallel light (collimated light) into the projection optical system, and performs projection based on the measurement light ML that has passed through the optical element in the projection optical system through which the exposure light EL passes. The optical characteristics of the optical system 30, that is, the internal state of the projection optical system 30 are measured. Specifically, the measurement unit 50 includes a light projection unit 51 that projects measurement light ML (light beam) into the projection optical system 30, and receives the measurement light ML that has passed through the projection optical system 30 and is emitted. It has a light receiving section 52. In the projection optical system 30, like the exposure light EL, the measurement light ML is transmitted to the upper surface of the trapezoidal mirror 31, the upper part of the reflective surface of the concave mirror 32, the convex mirror 33, the lower part of the reflective surface of the concave mirror 32, and the trapezoidal mirror 31. The light is reflected in the order of the lower surface and exits from the projection optical system 30.

The light projector 51 may include, for example, a light source 51a and a mirror 51b. The light source 51a includes 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 mirror 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 projection unit 51 (light source 51a, mirror 51b) is attached to the projection optical system 30 between the original stage 20 (original M) and the projection optical system 30. Further, the light projecting section 51 is configured so that the measurement light ML is parallel to the optical axis of the projection optical system 30 by a mirror 51b disposed between the original M and the projection optical system 30. By arranging the mirror 51b below the original M in this way, it is possible to always make the measurement light ML enter the projection optical system 30.

The light receiving section 52 may include, for example, a light receiving element 52a and a mirror 52b. The mirror 52b bends the optical path of the measurement light ML passed through the projection optical system 30 and 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 according to the light reception position of the measurement light ML. In the case of this embodiment, the light-receiving element 52a has a light-receiving surface 53 that receives the measurement light ML, and outputs a signal value according to the light-receiving position of the measurement light ML on the light-receiving surface 53. The specific configuration of the light receiving element 52a will be described later. The light receiving section 52 (light receiving element 52a, mirror 52b) is attached to the projection optical system 30 between the substrate stage 40 (substrate W) and the projection optical system 30. In the case of this embodiment, the projection optical system 30 is a double-sided telecentric optical system, and since the measurement light ML is incident parallel to the optical axis of the projection optical system 30, the measurement light ML is also applied to the substrate W side of the projection optical system 30. is emitted parallel to the optical axis. Further, since parallel light is used as the measurement light ML, there is no need to consider the imaging position of the projection optical system 30 with respect to the position where the light receiving element 52a (light receiving surface 53) is arranged. Therefore, the light-receiving element 52a (light-receiving surface 53) of this embodiment may be arranged at a position different from the imaging position of the projection optical system 30.

Here, when a semiconductor laser or an LED is used as the light source 51a of the light projecting section 51, it is possible to blink the measurement light ML at high speed, and therefore it is possible to emit the measurement light ML having a specific frequency. . 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 section 52 with the frequency of the measurement light ML emitted from the light source 51a. That is, it is possible to obtain the signal value of the light receiving element 52a focusing on a specific frequency component.

A plurality of measurement units 50 configured as described above may be provided for the exposure light EL. FIG. 2 is a diagram of the projection optical system 30 viewed from above (original stage 20 side), and shows the cross section of the exposure light EL (illumination area 11) and the light projection section 51 (light source 51a, mirror 51b) of the measurement section 50. is illustrated. The plurality of measurement units 50 can be arranged such that the plurality of measurement lights ML are respectively projected into the projection optical system 30 at a plurality of locations around the exposure light EL. In the example shown in FIG. 2, four measurement units 50 are provided, and the four measurement units 50 measure the optical axis (Z-axis direction) of the exposure light EL around the exposure light EL (illumination area 11). They are arranged symmetrically about a straight line that cuts across and is parallel to the scanning direction (X direction). By providing a plurality of measurement units 50 in this manner, not only the positional fluctuation (optical axis shift) of the measurement light ML within the projection optical system 30 but also the magnification component of the projection optical system 30 can be measured.

Note that the positional fluctuation of the measurement light ML means that the optical axis of the measurement light ML changes from the reference position to the translation direction (XY direction) and rotation direction (rotation direction around the Z axis) by passing through the projection optical system 30. It means to fluctuate (shift). Further, the reference position may be the optical axis position of the measurement light ML to be emitted from the projection optical system 30 depending on the position of incidence on the projection optical system 30.

Next, a method of measuring the optical characteristics of the projection optical system 30 using the light receiving element 52a of the light receiving section 52 will be 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 this embodiment, the light receiving element 52a may include a plurality of photodiodes configured to be able to detect light intensity in each of a plurality of partial regions on the light receiving surface 53. In the following, an example will be described in which four photodiodes (also referred to as four-division photodiodes) are used as the light receiving element 52a.

FIG. 3 is a diagram showing the light receiving surface 53 of the light receiving element 52a of this embodiment. In the case of this embodiment, the light-receiving surface 53 is the YZ plane as shown in FIG. 1, but in FIG. The case will be explained below. Further, in the example shown in FIG. 3, the light receiving element 52a is constituted by a four-part photodiode, and the light receiving surface 53 has four partial regions 53a to 53d whose light intensity can be individually detected. That is, the four-part photodiode as the light receiving element 52a is configured to individually output a signal value (for example, a current value) according to the amount of light incident on each of the partial regions 53a to 53d. Furthermore, the signal values (current values) individually output from the four-division photodiodes can be connected to a current-voltage converter and converted into voltage values.

For example, as shown in FIG. 3, consider a case where the measurement light ML is incident on the center position of the light receiving surface 53 (the center position of the four-part photodiode). In this case, four voltage values A, B, C, and D are obtained from each of the four-divided photodiode sections. These voltage values A, B, C, and D depend on the light intensity of the measurement light EL, the photodiode sensitivity, the current-voltage converter gain, and the like. Further, these voltage values change due to positional fluctuations 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, when the incident position (light receiving position) of the measurement light EL changes in the right direction (+X direction) from the state shown in FIG. The amount of light received decreases in the regions 53a and 53d. That is, voltage values B and C will increase, and voltage values A and D will decrease. On the other hand, when the incident position (light receiving position) of the measurement light EL moves upward (+Y direction) from the state shown in FIG. The amount of light received decreases in the regions 53a to 53b. That is, voltage values C and D will increase, and voltage values A and B will decrease.

Therefore, the control unit 60 can determine the light receiving position shift of the measurement light ML with respect to the center position of the light receiving surface 53 based on the voltage values A to D obtained from the four-divided photodiodes. The light receiving position shift of the measurement light ML on the light receiving surface 53 is proportional to the optical axis shift (X, Y) of the measurement light ML in the projection optical system 30, and is calculated by the following equations (1) and (2). sell. Note that the above calculation may be performed by the control unit 60 in this embodiment, but if the measurement unit 50 is provided with a processing unit such as a CPU, the calculation may be performed by the processing unit.
X=kx{-(A-C)+(BD)}...(1)
Y=ky{-(A-C)-(BD)}...(2)

The coefficient kx in equation (1) is a conversion coefficient ( (proportional coefficient). Similarly, the coefficient ky in equation (2) is used to convert the light receiving position deviation (Y direction) of the measurement light ML on the light receiving surface 53 into the optical axis deviation (Y direction) of the measurement light ML in the projection optical system 30. It is a conversion coefficient (proportionality coefficient). The coefficient kx and the coefficient ky can be determined, for example, by prior experimentation or simulation. As an example, while changing the incident position of the measurement light ML on the projection optical system 30 and shifting the optical axis of the measurement light ML on the projection optical system 30, the light reception position shift of the measurement light ML on the light reception surface 53 may be changed. By sequentially measuring , the coefficient kx and the coefficient ky can be obtained.

In addition, when the diameter of the measurement light ML is larger than the light receiving surface 53 of the 4-split photodiode, or when the width of the joint area (area where the light intensity cannot be detected) of the 4-split photodiode is so small that it cannot be ignored, the voltage The values A to D may be normalized. Specifically, when the total amount of light received in the plurality of partial regions 53a to 53d changes due to a shift in the light receiving position of the measurement light ML on the light receiving surface 53, as shown in the following equations (3) to (4), In addition, linearity can be mainly improved by normalizing the total amount of received light. Note that the coefficient kx' and the coefficient ky' in equations (3) to (4) are used to convert the light receiving position shift of the measurement light ML on the light receiving surface 53 into the optical axis shift of the measurement light ML in the projection optical system 30. It is a conversion coefficient (proportionality coefficient).
X=kx'{-(A-C)+(B-D)}/(A+B+C+D)...(3)
Y=ky'{-(A-C)-(B-D)}/(A+B+C+D)...(4)

Here, the measurement light ML passes through a plurality of optical elements within the projection optical system 30 through which the exposure light EL passes. Therefore, the optical axis shift of the measurement light ML in the projection optical system 30, which is calculated from the light reception position shift of the measurement light ML on the light receiving surface 53, is made to correspond to the positional variation (image shift) of the exposure light EL on the substrate. Can be done. That is, by performing the above calculation, the control unit 60 estimates the positional fluctuation of the exposure light EL in the projection optical system 30 based on the light receiving position of the measurement light ML in the light receiving element 52a (light receiving surface 53). Can be done. Then, the irradiation position of the exposure light EL on the substrate can be corrected according to the estimated positional variation of the exposure light EL. In the case of this embodiment, the correction of the irradiation position of the exposure light EL on the substrate can be performed in parallel with the scanning exposure of the substrate W.

In this way, in the exposure apparatus 100 of this embodiment, by using the measurement light ML that is parallel light, a plurality of photodiodes (for example, a 4-split photodiode) can be used as the light receiving element 52a. In other words, the configuration of this embodiment is compared to the conventional configuration that detects a projected image of a mark using an image sensor configured of a photodetection 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 configuration. Furthermore, in the configuration of the present embodiment, since the projected image of the mark is not used to measure the optical characteristics of the projection optical system 30, the light receiving surface 53 of the light receiving element 52a is Can be placed arbitrarily. That is, the light receiving surface 53 can be arranged at a position different from the image forming position of the projection optical system 30. Therefore, it is advantageous in terms of device cost and flexibility in device design. Furthermore, the configuration of this embodiment uses a photodiode, and the calculation scale is smaller than that of the conventional configuration that calculates the position of the projected image of the mark, so the measurement cycle of the optical characteristics of the projection optical system 30 is shortened. be able to. In other words, in the conventional configuration, the optical characteristics of the projection optical system 30 are measured discretely, whereas in the configuration of this embodiment, the optical characteristics of the projection optical system 30 can be measured continuously.

[Correction of exposure light irradiation position]
Changes in the optical characteristics of the projection optical system 30, that is, changes in the position of the exposure light EL in the projection optical system 30, are caused by, for example, vibrations of optical elements of the projection optical system 30, atmospheric fluctuations within the projection optical system 30 (air fluctuations). can be caused by When the positional fluctuation of the exposure light EL is caused by the optical elements (the trapezoidal mirror 31, the concave mirror 32, and the convex mirror 33) of the projection optical system 30, the control unit 60 drives the optical elements with the actuators 34 to 36 to The irradiation position of the exposure light EL on the substrate is corrected. On the other hand, when the positional fluctuation of the exposure light EL is caused by atmospheric fluctuations within the projection optical system 30, the control unit 60 controls the exposure light on the substrate by adjusting the temperature and/or pressure within the projection optical system 30. Correct the EL irradiation position. In the case of this embodiment, as shown in FIG. 1, an adjustment section 71 for adjusting the temperature and/or pressure within the projection optical system 30 may be provided.

An example of a method for correcting the irradiation position of the exposure light EL on the substrate based on the measurement result by the measurement unit 50 will be described. As described above, the positional fluctuation of the exposure light EL in the projection optical system 30 can be caused by vibrations of the optical elements of the projection optical system 30 and/or atmospheric fluctuations within the projection optical system 30. For example, the plurality of optical elements (for example, the trapezoidal mirror 31, the concave mirror 32, and the convex mirror 33) constituting the projection optical system 30 have different weights and therefore different natural frequencies (vibration frequencies). Therefore, by examining the frequency component of the fluctuation (vibration) of the light receiving position of the measurement light ML in the light receiving element 52a, it is possible to identify the optical element that is influencing the fluctuation of the light reception position of the measurement light ML, that is, the position fluctuation of the exposure light EL. can be specified.

In the case of this embodiment, the control unit 60 uses fast Fourier transform or the like to perform frequency analysis of fluctuations (vibrations) in the light receiving position of the measurement light ML in the light receiving element 52a (that is, decomposes it into a plurality of frequency components). . As a result of the frequency analysis, for example, if a frequency component corresponding to the natural frequency of the concave mirror 32 is obtained, the control unit 60 gives a command to the actuator 35 to damp the vibration of the concave mirror 32. let As an example, the control unit 60 performs coordinate conversion, gain adjustment, filtering, etc. with respect to the direction and magnitude of the light reception position shift of the measurement light ML with respect to the center position of the light receiving element 52a (light receiving surface 53). Thus, the command value for the actuator 35 is determined. By giving the command value determined 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 frequency of the trapezoidal mirror 31 and/or the convex mirror 33 is obtained, the control unit 60 gives a command value to the actuators 34 and 36, and The vibrations of the convex mirror 33 are damped.

Furthermore, if a frequency component lower than the natural frequency of each optical element of the projection optical system 30 is obtained as a result of frequency analysis, the influence of refractive index fluctuations due to atmospheric fluctuations (temperature, pressure) within the projection optical system 30 is possible. In this case, the control unit 60 adjusts the temperature and/or pressure within the projection optical system 30 using the adjustment unit 71 to reduce fluctuations in the light receiving position of the measurement light ML, that is, fluctuations in the position of the exposure light EL. Can be done. For example, the control unit 60 reduces the positional fluctuation of the exposure light EL by giving the adjustment unit 71 a command value for changing the control parameters of the atmosphere within the projection optical system 30, and reduces the irradiation of the exposure light EL on the substrate. Position can be corrected.

In the configuration in which a plurality of measurement units 50 are provided as shown in FIG. 2, positional fluctuations of the exposure light EL can be partially detected. In this case, the irradiation position of the exposure light EL can be selectively corrected in the portion where the position of the exposure light EL has changed. Furthermore, in the configuration shown in FIG. 2, it is possible to measure not only the translational direction and the rotational direction but also the magnification component of the projection optical system. It is also possible to correct the magnification component of .

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

[Estimation of exposure light fluctuation]
Next, the installation position of the light receiving element 52a in the measuring section 50 will be explained. When the optical path length of the exposure light EL from the projection optical system 30 to the substrate W is approximately 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 measurement light ML The fluctuation (vibration) of the exposure light EL and the fluctuation (vibration) of the exposure light EL may be considered to be substantially the same. In this case, the control unit 60 assumes that a variation (vibration) in the exposure light EL that is approximately the same as the variation (vibration) in the measurement light ML obtained by the light receiving element 52a is occurring, and controls the actuator 34-36. can be controlled. However, various components for exposure are arranged in the area between the projection optical system 30 and the substrate W (substrate stage 40), making it difficult to arrange the light receiving element 52a at a desired location. There are cases.

If the optical path length from the projection optical system 30 cannot be arranged to be approximately the same for the exposure light EL and the measurement light ML, based on the amount of variation (light reception position shift amount) of the measurement light ML obtained by the light receiving element 52a, It is preferable to estimate the amount of variation in the exposure light EL (the amount of shift in the irradiation position on the substrate). For example, assume that the exposure light EL and the measurement light ML are bent by the same angle due to each optical element of the projection optical system 30 vibrating. In this case, due to the difference between the optical path length of the bent measurement light ML until it reaches the light receiving element 52a and the optical path length of the bent exposure light until it reaches the substrate W, The amount of variation in the measurement light ML on the light receiving surface 53 may be different from the amount of variation in the exposure light EL on the substrate. However, since these optical path lengths can be known, using their optical path length ratio as a conversion coefficient, the amount of variation in the measurement light ML on the light receiving element 52a can be calculated as the variation in the exposure light EL on the substrate. It can be converted into quantity.

Here, the plurality of optical elements (the trapezoidal mirror 31, the concave mirror 32, and the convex mirror 33) in the projection optical system 30 are generally arranged at different locations in the optical path length of the exposure light EL. In other words, the optical path length of the exposure light EL to the substrate W may be different between the plurality of optical elements. Therefore, if the amount of variation in the measurement light ML on the light-receiving element 52a is simply converted into the amount of variation in the exposure light EL on the substrate using a conversion factor that is commonly set for a plurality of optical elements, An error may occur in the amount of variation in the exposure light EL on the actual substrate. Therefore, it is preferable to set a conversion factor for each optical element.

In the case of this embodiment, since the optical path amount to the light receiving element 52a and the optical path length to the substrate W are known for each optical element, the conversion coefficient is calculated for each optical element (for each natural frequency) based on the optical path length ratio. is set to . The control unit 60 uses fast Fourier transform or the like to convert the time-axis data of the amount of variation in the measurement light ML obtained by the light-receiving element 52a into frequency-axis data, performs frequency analysis, and calculates the frequency obtained from the analysis result. Based on the components, the optical element caused by the vibration of the measurement light ML is specified. As described above, the plurality of optical elements in the projection optical system 30 have different natural frequencies (vibration frequencies), so from the frequency components obtained as a result of frequency analysis, it is possible to determine which optical element is caused by vibration. It is possible to specify whether the optical ML is vibrating. Therefore, the control unit 60 selects a conversion factor that is set in association with the identified optical element, and converts the amount of variation in the measurement light ML on the light receiving element 52a into the amount of variation in the exposure light EL on the substrate. It can be converted. This makes it possible to reduce errors occurring in the amount of variation in exposure light EL on the actual substrate.

In addition, in each optical element of the projection optical system 30, when the exposure light EL and the measurement light ML are reflected or transmitted at different locations, or in order to prevent the resist on the substrate from being exposed, the exposure light EL and the measurement light ML may be The wavelengths may be different. In this case, since the degree of influence due to vibration of each optical element may be different between the exposure light EL and the measurement light ML, the amount of variation in the measurement light ML on the light receiving element 52a is converted into the amount of variation in the exposure light EL on the substrate. Errors may occur when doing so. Therefore, the difference in the degree of influence of vibration of each optical element between the exposure light EL and the measurement light ML (hereinafter sometimes referred to as "influence difference") is determined by experiment or simulation, and the difference is reduced. It is recommended to correct the conversion factor. For example, using a conversion factor set in advance, the amount of variation in the measurement light ML on the light receiving element 52a is converted into the amount of variation in the exposure light EL on the substrate, and the amount of variation in the obtained exposure light EL is converted into the amount of variation in the exposure light EL on the substrate. Based on this, scanning exposure of the substrate W is performed while correcting the irradiation position of the exposure light EL on the substrate. If an error such as image shift or uneven exposure occurs in the pattern actually formed on the substrate by the scanning exposure (for example, an overlay error with the underlying pattern), the error is caused by the difference between the exposure light EL and the measurement light ML. This may correspond to the difference in the degree of influence. Therefore, the conversion coefficient can be corrected so that the error is reduced.

As described above, the amount of variation in the measurement light ML on the light receiving element 52a may be caused by atmospheric fluctuations (air fluctuations) within the projection optical system 30. Since the measurement light ML and the exposure light EL pass through the same space within the projection optical system 30, the measurement light ML is affected by atmospheric fluctuations that are substantially the same as the exposure light EL. Therefore, based on the amount of variation in the measurement light ML on the light receiving element 52a, it is possible to estimate the amount of variation in the exposure light EL on the substrate due to atmospheric fluctuations within the projection optical system 30.

For example, in the result of frequency analysis of the variation amount of the measurement light ML on the light receiving element 52a, at least part of the frequencies other than the natural frequency of the optical elements of the projection optical system 30 described above This can be considered as the influence of fluctuation. The control unit 60 may correct the amount of variation in the exposure light EL due to this atmospheric fluctuation by adjusting the temperature and/or pressure within the projection optical system 30 with the adjustment unit 71, or may correct the amount of variation in the exposure light EL due to atmospheric fluctuations by adjusting the temperature and/or pressure within the projection optical system 30 with the adjustment unit 71. The correction may be made by driving each optical element of the optical system 30. Note that the measurement unit 50 of this embodiment can also be used as a sensor that monitors the degree of influence of atmospheric fluctuations within the projection optical system 30 on the exposure light EL during scanning exposure. Therefore, it may be utilized for the development of hardware and device driving software for reducing the atmospheric fluctuations.

[Method for improving measurement accuracy]
In order to improve the measurement accuracy of the amount of variation in the measurement light ML in the measurement section 50 and to correct the irradiation position of the exposure light EL on the substrate with higher precision, the detection resolution of the measurement light ML in the light receiving element 52a must be increased. It is good to increase it. Below, several methods for increasing the detection resolution will be described.

The first method is to reduce noise as much as possible. In addition to the original signal value of the measurement light ML, the signal value output from the light receiving element 52a includes noise components due to disturbance light other than the measurement light ML, electrical noise components generated by the current-voltage converter, etc. It will be done. Therefore, by reducing these noise components as much as possible, the S/N ratio can be improved and the detection resolution can be improved. As a method for reducing the disturbance light, there is a method of blocking light around the light receiving element 52a or using a wavelength filter to block disturbance light other than the measurement light ML. Further, as a method of reducing the electrical noise component, there are methods of making the current-voltage converter used as low as possible, or shielding the area around the light receiving element 52a from the surrounding electromagnetic field. Further, since the noise and gain of the current-voltage converter are correlated with each other, it is preferable to set the noise and gain in consideration of the balance between the two.

A second method is to make the diameter of the measurement light ML incident on the light receiving element 52a as small as possible. The smaller the diameter of the measurement light ML, the sharper the light intensity distribution becomes. Therefore, even with the same amount of variation in the measurement light ML, the signal value obtained from the four-divided photodiode (each partial region 53a to 53d) can change significantly. Can be done. This means that the sensitivity is increased, and the signal side of the S/N ratio is increased, making it possible to detect smaller positional fluctuations.

As a third method, the light intensity (light amount) of the measurement light ML is adjusted so that the voltage values A to D output from the light receiving element 52a (four-division photodiode) are close to the maximum output of the current-voltage converter. There is a way to do it. This also has the effect of increasing the voltage fluctuation (signal) of the light receiving element 52a due to the positional fluctuation of the measurement light ML, so the sensitivity of the light receiving element 52a can be increased. For example, the light intensity (light amount) of the measurement light ML output from the light source 51a is set to be larger than the required light intensity, and the light transmittance of the ND filter placed between the light source 51a and the light receiving element 52a is changed. By doing so, the light intensity of the measurement light ML can be adjusted.

A fourth method is to make it possible to measure minute voltages by performing measurements using a high-resolution measurement system. Alternatively, by amplifying the signals (AC) and (BD) in the above equations (1) to (4) using a differential amplifier, the voltage values A, B, and It is also possible to improve the resolution by making it possible to measure minute voltage components included in C and D.

However, since the output of a differential amplifier is generally limited, the absolute values of the differential components (A-C) and (B-D) should be as small as possible, and each voltage value A, B, C, D It is preferable to set the average voltage of each to be the same. For example, when using a differential amplifier with a maximum output of 10 [V], and when the average value of voltage value A is 8 [V] and the average value of voltage value C is 7 [V], the amplification of the differential amplifier Maximum magnification is only 10x. On the other hand, when the average value of voltage value A is 8.0 [V] and the average value of voltage value C is 7.9 [V], the amplification factor of the operational amplifier can be increased up to 100 times, so It becomes possible to amplify and detect even minute voltage components.

In order to similarly adjust the average voltage level of each of the voltage values A, B, C, and D described above, it is preferable that the light intensity distribution of the measurement light ML be made symmetrical with respect to the optical axis. Further, it is preferable to include a mechanism for adjusting the relative position between the measurement light ML and the light receiving element 52a. In the light receiving element 52a, its position relative to the projection optical system 30 may change due to thermal deformation of its fixed portion. Therefore, if the exposure apparatus 100 is provided with an adjustment mechanism for adjusting the position and/or attitude of the light receiving element 52a with respect to the projection optical system 30 in the plane direction (two orthogonal directions) perpendicular to the optical axis of the measurement light ML to be received. good.

Furthermore, in the measurement section 50, the light source 51a of the light projecting section 51 may change the emission direction and the emission position of the measurement light ML. Further, similarly to the light receiving element 52a, the light source 51a may also fluctuate in the emission direction and emission position of the measurement light ML due to thermal deformation of its fixed portion. As described above, if a change occurs in the emission direction or the emission position of the measurement light ML in the light source 51a, it may become difficult to make the measurement light ML enter the projection optical system 30 at a desired incident angle and incident position. As a result, an error caused by the measurement unit 50 itself may occur in the amount of variation in the exposure light EL on the substrate, which is converted from the amount of variation in the measurement light ML on the light receiving element 52a. Therefore, if the exposure apparatus 100 is provided with an adjustment mechanism for adjusting the position and/or attitude of the light source 51a with respect to the projection optical system 30 so as to change the position and/or inclination of the measurement light ML emitted from the light source 51a. good.

Note that while the position/orientation of the light source 51a and/or the light receiving element 52a is being adjusted, the amount of variation in the measurement light ML cannot be measured. Therefore, during scanning exposure of the substrate W, the position/orientation of the light source 51a and/or the light receiving element 52a is not adjusted. It is preferable to perform this during processing other than scanning exposure, such as during processing.

Here, in this embodiment, the projection optical system 30 has been described as a reflective optical system, but it may also be a refractive optical system or a catadioptric optical system. Although the shape of the illumination area 11 (cross section of the exposure light EL) shown in FIG. The same effect as arranging the light source 51a nearby can be obtained. Further, in this embodiment, a four-split photodiode is used as the light receiving element 52a, but a plurality of non-split type photodiodes may be used and optically split using a prism or a beam splitter. Further, in the present embodiment, an example in which a plurality of measurement units 50 (light receiving elements 52a) are arranged has been described, but only one measurement unit 50 (light receiving element 52a) is arranged, and the amount of variation in measurement light ML in the translation direction is It is also possible to measure only the

<Second embodiment>
A second embodiment according to the present invention will be described. Since this embodiment basically inherits the first embodiment, the differences from the first embodiment will be explained below. In the first embodiment, the actuators 34 to 36 drive each optical element of the projection optical system 30, and/or the adjustment section 71 adjusts the atmosphere (temperature, pressure) inside the projection optical system 30. , the irradiation position of the exposure light EL on the substrate was corrected. In this embodiment, an example will be described in which the irradiation position of the exposure light EL on the substrate is corrected by changing the relative position between the original M and the substrate W.

In the case of this embodiment, the control unit 60 estimates the amount of variation in the exposure light EL on the substrate from the amount of variation in the measurement light ML on the light receiving element 52a. Specifically, the amount of variation in the measurement light ML on the light receiving element 52a is converted into the amount of variation in the exposure light EL on the substrate using a conversion coefficient set in advance. Then, the control unit 60 controls (adjusts) the position of the substrate W by driving the substrate stage 40 so that the estimated amount of variation in the exposure light EL is corrected.

For example, by averaging the signal values output from the light-receiving element 52a, or by extracting rotational components and moving averages of the illumination area 11, by performing coordinate transformation, gain adjustment, filtering, etc., the amount of variation in the exposure light EL Find the command value to correct. Then, the obtained command value is added to the command value for scanning the substrate W and is supplied to the substrate stage 40. In this way, when the amount of variation in the exposure light EL is corrected by driving the substrate stage 40, it is not necessary to provide the actuators 34 to 36 for driving the optical elements of the projection optical system 30, which simplifies the device configuration. can be achieved. Further, in this embodiment, a configuration has been described in which a command value for correcting the amount of variation in exposure light EL is supplied to the substrate stage 40, but a configuration in which the command value is supplied to the original stage 20 may be used. Further, the amount of variation in the exposure light EL may be corrected relatively by driving the substrate stage 40 and the original stage 20. Furthermore, if a drive mechanism for driving the projection optical system 30 is provided, the amount of variation in the exposure light EL may be corrected by driving the projection optical system 30.

<Third embodiment>
A third embodiment according to the present invention will be described. Since this embodiment basically inherits the first embodiment and/or the second embodiment, the points that are different from those embodiments will be described below.

In the measuring section 50, the light projecting section 51 (light source 51a) may fluctuate in the emission direction and the emission position of the measurement light ML. In this way, when a fluctuation occurs in the emission direction or the emission position of the measurement light ML in the light projection unit 51 (that is, a deviation from the target emission direction/position), the projection optical system 30 performs measurement at the desired incident angle and incident position. It becomes difficult to make the light ML incident. As a result, an error caused by the measurement unit 50 itself may occur in the amount of variation in the exposure light EL on the substrate, which is converted from the amount of variation in the measurement light ML on the light receiving element 52a. This error is a measurement deception component that does not occur in the exposure light EL. Therefore, the amount of variation in the exposure light EL on the substrate is estimated based on the light reception result of the light receiving element 52a where the error has occurred, and the exposure light EL is irradiated onto the substrate based on the amount of variation in the exposure light EL. Correcting the position may result in deterioration in imaging performance such as a decrease in contrast or image shift.

Therefore, the measurement unit 50 of the present embodiment detects at least one of the emission angle and the emission position (hereinafter sometimes referred to as "emission angle, etc.") of the luminous flux emitted from the light projection unit 51 (light source 51a). It has a detection section 54. In other words, the detection unit 54 converts 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 into the measurement light caused by the measurement unit 50. It may be configured to detect as an offset position variation amount of ML. Further, in the case of the present embodiment, the control unit 60 corrects the amount of variation in the measurement light ML on the light receiving element 52a based on the amount of offset position variation detected by the detection unit 54, and the value obtained thereby. Based on this, it is possible to estimate the amount of variation in the exposure light EL on the substrate.

FIG. 4 is a schematic diagram showing the configuration of an exposure apparatus 300 according to the third embodiment. The exposure apparatus 300 of this embodiment differs from the exposure apparatus 100 of the first embodiment in that a detection section 54 is provided in the measurement section 50. The rest of the configuration is the same as that of the exposure apparatus 100 of the first embodiment, so a description thereof will be omitted.

The detection unit 54 is provided outside the projection optical system 30, and includes, for example, a beam splitter 54a (second branch), a light receiving element 54b (second light receiving element), a light receiving element 54c (third light receiving element), A mirror 54d may be included. Each component of the detection unit 54 (beam splitter 54a, light receiving elements 54b, 54c, mirror 54d) is fixed relative to the projection optical system 30, and preferably attached to the projection optical system 30. Furthermore, in the configuration of the measuring section 50 of this embodiment, a beam splitter 55 (branching section) is provided in place of the mirror 51b of the light projecting section 51.

The light beam emitted from the light source 51a of the light projector 51 is split into two light beams by the beam splitter 55. One of the two light beams split by the beam splitter 55 is guided into the projection optical system 30 as the measurement light ML, and the other beam is a detection light for detecting the incident angle of the measurement light ML. The light is guided to the detection section 54 (beam splitter 54a) as DL. The detection light DL guided to the detection unit 54 is split 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 mirror 54d, and the other light beam is split into two light beams by the beam splitter 54a. The light flux (second detection light DL2) is guided to the light receiving element 54c. Here, the light receiving elements 54b and 54c have the same configuration as the light receiving element 52a of the light receiving section 52, for example, and may be formed by a four-part photodiode. Therefore, the method for determining the amount of variation in the detection light DL on the light receiving surface of each of the light receiving elements 54b and 54c is the method (first This is the same as the content described in the embodiment).

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 from each other in this way, the amount of variation in the first detection light DL on the light receiving surface of the light receiving element 54b and the amount of variation on the light receiving surface of the light receiving element 54c will be different. The amount of variation in the second detection light DL is different from each other. Therefore, the control unit 60 controls the light projecting unit 51 (light source It is possible to detect the emission angle of the luminous flux emitted from 51a). Furthermore, since the positional relationship among the light projector 51 (light source 51a), beam splitter 55, and projection optical system 30 is known, the incident angle of the measurement light ML to the projection optical system 30 can be determined based on the output angle, etc. It can be obtained as an offset position variation amount.

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 section 52. The amount of variation in the measurement light ML obtained by the light receiving element 52a includes a component caused by vibrations of each optical element of the projection optical system 30, a component caused by atmospheric fluctuations within the projection optical system 30, and a component caused by measurement to the projection optical system 30. It may include components caused by the measurement unit 50 itself, such as errors in the incident angle of the light ML. In the case of the present embodiment, the control unit 60 removes the offset position variation amount detected by the detection unit 54 from the variation amount of the measurement light ML on the light receiving element 52a, and based on the obtained value, The amount of variation in exposure light EL on the substrate is estimated. In this way, by estimating the amount of variation in the exposure light EL on the substrate based on the value obtained by removing the amount of offset position variation caused by the measurement unit 50 itself, the amount of variation in the exposure light EL on the substrate can be adjusted. The irradiation position can be corrected with high accuracy.

<Fourth embodiment>
A fourth embodiment according to the present invention will be described. In this embodiment, a modification of the third embodiment will be described in which the measuring section 50 is provided with a detecting section 54 that detects the offset position variation amount. Since this embodiment basically inherits the third embodiment, the differences from the third embodiment will be described below.

FIG. 5 is a schematic diagram showing the configuration of an exposure apparatus 400 according to the fourth embodiment. In the exposure apparatus 400 of this embodiment, compared to the exposure apparatus 300 of the third embodiment, the light receiving element 54c is removed from the measurement section 50 (detection section 54). That is, the detection unit 54 of this embodiment is configured by a light receiving element 54b (second light receiving element).

The light beam emitted from the light source 51a of the light projector 51 is split into two light beams by the beam splitter 55. One of the two light beams split by the beam splitter 55 is guided into the projection optical system 30 as the measurement light ML, and the other beam is a detection light for detecting the incident angle of the measurement light ML. The light is guided to the light receiving element 54b as DL. Here, the measurement unit 50 of the present embodiment is configured such that the optical path length of the detection light DL received by the light receiving element 54b is approximately 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. It is composed of For example, the detection light DL is routed by a plurality of mirrors so that the optical path length is substantially the same as the measurement light ML, and is received by the light receiving element 54b.

Specifically, the detection unit 54 is configured so that the optical path of the measurement light ML and the optical path of the detection light DL are substantially the same. Since the optical path length of the measurement light ML passes through a plurality of optical elements in the projection optical system 30, it is not realistic to connect the optical path of the detection light DL in a straight line within the apparatus. Therefore, it is desirable to use optical elements such as bending mirrors and retroreflectors to increase the optical path length in a limited space. Further, these optical elements for enlarging the optical path length may be fixed relatively to the projection optical system 30, and preferably attached to the projection optical system 30. As a result, the measurement light deviation can be measured with the projection optical system 30 alone, so it can be used for unit inspection of the projection optical system unit alone before assembly of the exposure apparatus.

In such a configuration, assuming that there is no vibration of each optical element or atmospheric fluctuation in the projection optical system 30, the amount of variation in the measurement light ML on the light receiving element 52a and the detection light DL on the light receiving element 54b are The amount of variation can be the same. In other words, the difference between the amount of variation in the measurement light ML obtained by the light receiving element 52a and the amount of variation in the detection light DL obtained by the light receiving element 54b is caused by vibrations of each optical element in the projection optical system 30 and atmospheric fluctuations. It becomes the ingredient that Therefore, the control unit 60 removes the variation amount of the detection light DL on the light receiving element 54 from the variation amount of the measurement light ML on the light receiving element 52a, and based on the value obtained thereby, It is possible to estimate the amount of variation in the exposure light EL.

Here, the optical path lengths being substantially the same means that even if the measurement light ML or detection light DL fluctuates (for example, tilt variation), the amount of variation in the light receiving position on the light receiving element caused by the variation can be considered to be substantially the same. It means the extent to which it is possible. This varies depending on the application, and the range may change depending on the measurement accuracy (resolution) of the target positional variation, the amount of variation in the emission angle of the light beam from the light source 51a, etc. For example, if the slope variation of the measurement light ML due to the light source 51a and its fixed system is about 10 μrad, and if you want to set the measurement error due to the optical path length error to 10 nm or less, the optical path length error needs to be suppressed to about 1 mm. be. In this case, substantially the same optical path length corresponds to a difference in optical path length of 1 mm or less. On the other hand, if the measurement error due to the optical path length error is allowed to be as large as about 1 μm, the optical path length error may be about 100 mm. In this case, substantially the same optical path length may be defined as a difference in optical path length of 100 mm or less, and even a large difference in optical path length compared to the previous example can be considered to be substantially the same.

<Fifth embodiment>
A fifth embodiment according to 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. FIG. 6 is a flowchart showing the exposure process. Each step of the flowchart shown in FIG. 6 can be controlled by the control unit 60.

In S1, the control unit 60 uses a substrate transport mechanism (not shown) to carry the substrate W onto the substrate stage 40, and causes the substrate stage 40 to hold the substrate W. In S2, the control unit 60 performs global alignment processing. For example, the control unit 60 uses an alignment scope (not shown) to measure the position of an alignment mark formed in a sample shot area among a plurality of shot areas on the substrate W, and statistically processes the measurement results. Obtain array information for multiple shot areas.

In S3, the control unit 60 sequentially performs scanning exposure for each of the plurality of shot areas, and transfers the pattern of the original M as a latent image pattern to each shot area (specifically, the photosensitive material (resist) thereon). do. In the scanning exposure of each shot area in S3, as explained in the first to fourth embodiments, the measuring unit 50 measures the optical characteristics of the projection optical system 30, and based on the measurement results, the optical characteristics of the projection optical system 30 are scanned onto the substrate. The irradiation position of the exposure light EL is corrected. That is, in the scanning exposure of each shot area, the irradiation position of the exposure light EL can be corrected in real time based on the measurement result by the measurement unit 50.

In S4, the control unit 60 transports the substrate W from the substrate stage 40 using a substrate transport mechanism (not shown). 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 scanning exposure is performed on the next substrate. On the other hand, if there is no next substrate, the process ends.

<Embodiment of article manufacturing method>
The article manufacturing method according to the embodiment of the present invention is suitable for manufacturing articles such as micro devices such as semiconductor devices and elements having fine structures. The method for manufacturing an article of the present embodiment includes a step of forming a latent image pattern on a photosensitive agent applied to a substrate using the above-mentioned exposure device (a step of exposing the substrate), and a step of forming a latent image pattern in this step. The method includes a step of developing (processing) the substrate. Additionally, such manufacturing methods include other well-known steps (oxidation, deposition, deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, etc.). 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 compared to conventional methods.

The invention is not limited to the embodiments described above, and various changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, the following claims are hereby appended to disclose the scope of the invention.

10: illumination optical system, 20: original stage, 30: projection optical system, 40: substrate stage, 50: measurement section, 51: light projecting section, 52: light receiving section, 53: light receiving surface, 54: detecting section, 60: Control unit, 100: Exposure device

Claims (19)

An exposure device that exposes a substrate,
a projection optical system that includes a plurality of optical elements and projects a pattern image of the original onto the substrate using exposure light;
a measurement unit that measures 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 passes;
a control unit that corrects the irradiation position of the exposure light on the substrate based on the measurement result of the measurement unit;
including;
The measurement unit includes a light receiving element that receives the measurement light,
The control unit identifies, from the plurality of optical elements, an optical element that is affecting the positional fluctuation of the exposure light based on a frequency component of the positional fluctuation of the measurement light on the light receiving element. An exposure apparatus , comprising: correcting the irradiation position of the exposure light on the substrate by driving a specified optical element . An exposure device that exposes a substrate,
a projection optical system that projects a pattern image of the original onto the substrate using exposure light;
a measurement unit that measures 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 passes;
a control unit that corrects the irradiation position of the exposure light on the substrate based on the measurement result of the measurement unit;
including;
The measurement unit includes a light receiving element that receives the measurement light,
When the control unit identifies that atmospheric fluctuations within the projection optical system are affecting the positional fluctuations of the exposure light based on the frequency components of the positional fluctuations of the measurement light on the light receiving element, An exposure apparatus characterized in that an irradiation position of the exposure light on the substrate is corrected by adjusting an atmosphere within the projection optical system. 3. The exposure apparatus according to claim 1, wherein the light receiving element is attached to the projection optical system. The light receiving element has a light receiving surface that receives the measurement light,
4. The exposure apparatus according to claim 1, wherein the light receiving surface is arranged at a position different from an image forming position of the projection optical system. The measurement section further includes a light projection section that projects the measurement light into the projection optical system,
5. The exposure apparatus according to claim 1, wherein the light projector is attached to the projection optical system. 6. The exposure apparatus according to claim 5 , wherein the light projecting section projects the measurement light parallel to the optical axis of the projection optical system. 7. The exposure apparatus according to claim 5 , wherein the light projecting section is arranged between the original and the projection optical system. 8. The exposure apparatus according to claim 1, wherein the projection optical system includes a double-sided telecentric optical system. 9. The exposure apparatus according to claim 1, wherein the light receiving element includes a photodiode. The control unit estimates a positional variation of the exposure light within the projection optical system based on a light-receiving position of the measurement light on the light-receiving element, and controls the exposure light according to the estimated positional variation of the exposure light. 10. The exposure apparatus according to claim 1, further comprising correcting an irradiation position of the exposure light on the substrate. The measurement unit further includes a detection unit that detects at least one of an incident angle and an incident position of the measurement light into the projection optical system,
11. The exposure apparatus according to claim 10 , wherein the control section estimates a positional variation of the exposure light within the projection optical system based further on the detection result of the detection section. The detection unit includes a branching unit that branches part of the light from the measurement light before being projected into the projection optical system as detection light, and a branching unit that receives the detection light without going through the projection optical system. 2 light receiving elements, and detecting 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. The exposure apparatus according to claim 11 , characterized in that: The second light receiving element is arranged so that the optical path length of the detection light and the optical path length of the measurement light are the same,
The control unit controls the exposure light within the projection optical system based on the difference between the positional variation of the measurement light on the light receiving element and the positional variation of the detection light on the second light receiving element. 13. The exposure apparatus according to claim 12 , wherein the exposure apparatus estimates positional fluctuations. The detection unit includes a second branching unit that branches the detection light into a first detection light and a second detection light, and a third light receiving element that receives the second detection light without going through the projection optical system. Furthermore, it includes
The second light receiving element receives the first detection light,
The control section is configured to control the position of the first detection light on the second light receiving element based on the difference between the positional variation of the first detection light on the second light receiving element and the positional variation of the second detection light on the third light receiving element. 13. The exposure apparatus according to claim 12 , wherein the exposure apparatus corrects the positional fluctuation of the measurement light and estimates the positional fluctuation of the exposure light within the projection optical system based on the value obtained thereby. . 15. The optical path length of the first detection light received by the second light receiving element and the optical path length of the second detection light received by the third light receiving element are different from each other. exposure equipment. An exposure device that exposes a substrate,
a projection optical system that projects a pattern image of the original onto the substrate using exposure light;
a measurement light source that is a light source different from the exposure light source that emits the exposure light and that emits parallel light;
a measurement unit that measures optical characteristics of the projection optical system using measurement light emitted from the measurement light source via an optical element of the projection optical system through which the exposure light passes;
a control unit that estimates a positional change in the irradiation position of the exposure light on the substrate based on the result measured by the measurement unit;
including;
The measurement unit includes a light receiving element that receives the measurement light,
An exposure apparatus characterized in that the light receiving element receives the measurement light that is parallel light . The light receiving element has a light receiving surface that receives the measurement light,
17. The exposure apparatus according to claim 16, wherein the light-receiving surface is arranged at a position different from an imaging position at which the pattern image of the original is formed via the projection optical system. 18. The exposure apparatus according to claim 16, wherein the light receiving element and the measurement light source are attached to the projection optical system. A step of exposing the substrate using the exposure apparatus according to any one of claims 1 to 18 ,
Developing the substrate exposed in the step,
A method for manufacturing an article, comprising manufacturing an article from the developed substrate.

Images