Exposure apparatus, exposure method, and article manufacturing method

Abstract

To provide a technique advantageous in performing focus driving of a stage holding a substrate with high accuracy.SOLUTION: An exposure apparatus that exposes a substrate using the step-and-repeat method includes: a slider that moves on a surface plate; a fine movement stage that adjusts the tilt of the substrate on the slider; a stage that holds the substrate; a first measurement unit that measures the tilt of the fine movement stage relative to the surface plate to obtain a first measurement value; and a second measurement unit that measures the tilt of the fine movement stage relative to the slider to obtain a second measurement value; and a processing unit that calculates the inclination of the slider relative to the surface plate from the first measurement value and the second measurement value obtained during the step movement of the stage, and based on the inclination of the slider, calculates a correction value for correcting the position of the stage in an optical axis direction during focus drive to align the position of the substrate in the optical axis direction of a projection optical system with the focal plane of the projection optical system after the step movement of the stage.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Steppers, which transfer the pattern of a master onto a substrate using a step-and-repeat method, are known as exposure devices used in the manufacturing process of semiconductor devices, etc. Such exposure devices often use a substrate stage that is levitated by air pressure and obtains thrust using a linear motor.

[0003] The position of the substrate stage is measured by an interferometer system installed on the fixed base, while the height of the substrate stage is measured by an encoder (height measuring device) installed on the substrate stage due to space restrictions within the equipment, the increased weight of the movable parts of the substrate stage, and issues related to the cost of the interferometer system.

[0004] When driving the substrate stage in the horizontal direction, if the center of gravity of the substrate stage is not positioned on the line of action of the linear motor's thrust, a pitching moment will be generated on the substrate stage. The pitching moment then applies force to the part of the substrate stage that is levitated by air pressure, specifically the air pads, causing fluctuations in the air gap. However, the encoder installed on the substrate stage is insensitive to air gap fluctuations because it uses the fixed surface plate as its reference. Therefore, if the height of the substrate surface is measured using a focus measurement device installed above the substrate when a pitching moment is generated on the substrate stage, the measurement value (focus value) will include an error corresponding to the air gap fluctuation.

[0005] Therefore, a technique has been proposed in which the amount of variation in focus value in a dynamic state when the substrate stage is driven is acquired in advance, and the amount is stored as an offset for each direction of step drive of the substrate stage for correction (see Patent Document 1). In this way, conventional exposure apparatuses acquire a reproducible linear component offset and correct (compensate) the height of the substrate stage during focus measurement. Specifically, the height of the substrate stage is corrected taking into account the offset in addition to the measurement value of the height of the substrate stage obtained by an encoder, the measurement value of the tilt (posture) of the substrate stage obtained by an interferometer, and a value calculated from the horizontal position of the substrate stage. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-109531 Summary of the Invention [Problem to be solved by the invention]

[0007] However, with conventional technology, if the offset (amount of change in focus value) acquired while there is a change in the air gap changes as the device is operated, it is not possible to correct the height of the substrate stage with high precision. While it is possible to periodically update the offset, this would be time-consuming because the offset would have to be acquired every time it changes.

[0008] The present invention has been made in view of the above problems of the conventional technology, and has an exemplary object to provide a technology that is advantageous for performing focus driving of a stage that holds a substrate with high precision. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, an exposure apparatus as one aspect of the present invention is an exposure apparatus that exposes a substrate by a step-and-repeat method, and is characterized by having: a stage that holds the substrate, including a slider that moves on a base plate and a fine movement stage that adjusts the tilt of the substrate on the slider; a projection optical system that projects a pattern of an original onto the substrate held by the stage; a first measurement unit that measures the tilt of the fine movement stage with respect to the base plate to obtain a first measurement value; a second measurement unit that measures the tilt of the fine movement stage relative to the slider to obtain a second measurement value; and a processing unit that determines the tilt of the slider relative to the base plate from the first measurement value and the second measurement value obtained during step movement of the stage, and that determines a correction value based on the tilt of the slider to correct the position of the stage in the optical axis direction in focus drive that aligns the position of the substrate in the optical axis direction with the focal plane of the projection optical system after step movement of the stage.

[0010] Further objects and other aspects of the present invention will become apparent from the following description of the embodiments with reference to the accompanying drawings. [Effects of the Invention]

[0011] According to the present invention, for example, it is possible to provide a technique that is advantageous for performing focus driving of a stage that holds a substrate with high precision. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic diagram showing the configuration of an exposure apparatus according to one aspect of the present invention. [Figure 2] 10A and 10B are diagrams showing timing charts of the horizontal position of the substrate stage, the height of the fine movement stage, and the tilt of the slider. [Figure 3] 10 is a flowchart illustrating a method for obtaining a reference difference. [Figure 4] 10 is a flowchart illustrating a method for obtaining a reference difference. [Figure 5]FIG. 4 is a control block diagram for controlling the vertical position of the substrate stage. [Figure 6] 10A and 10B are diagrams showing timing charts of the horizontal position of the substrate stage, the horizontal acceleration of the substrate stage, and the tilt of the slider. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0014] First Embodiment 1 is a schematic diagram showing the configuration of an exposure apparatus 1 according to one aspect of the present invention. The exposure apparatus 1 is a lithography apparatus used in, for example, a lithography process, which is a manufacturing process for devices such as semiconductor elements, to form a pattern on a substrate. The exposure apparatus 1 is an exposure apparatus (stepper) that fixes an original (reticle or mask) and transfers the pattern of the original onto the substrate, i.e., that exposes the substrate using a step-and-repeat method.

[0015] In this specification and the accompanying drawings, directions are indicated in an XYZ coordinate system, with the direction parallel to the surface on which the substrate is placed being the XY plane. The directions parallel to the X-axis, Y-axis, and Z-axis in the XYZ coordinate system are defined as the X direction, Y direction, and Z direction, respectively, and rotation around the X-axis, Y axis, and Z axis are defined as θX, θY, and θZ, respectively. In this embodiment, the X direction and Y direction are defined as horizontal directions, and the Z direction is defined as vertical direction.

[0016] As shown in FIG. 1, the exposure apparatus 1 has a substrate stage SS, a projection optical system 102, a focus measurement device FM, a storage unit SU, and a control unit CU.

[0017] The substrate stage WS is a stage that holds the substrate ST and is driven by, for example, a linear motor. The substrate stage WS includes a slider 115 that moves on (above) a stage base 118, an air pad 117 that levitates the slider 115 above the stage base 118 with air pressure, and a fine-motion stage 107 that adjusts the height and tilt of the substrate ST on the slider.

[0018] The substrate stage WS is provided with three or more height measuring devices 113 that measure the height and tilt of the fine movement stage 107. In this embodiment, the height measuring device 113 functions as a measurement unit (second measurement unit) that measures the tilt of the fine movement stage 107 with respect to the slider 115 and acquires a tilt measurement value (second measurement value). In this embodiment, the height measuring device 113 is configured as an encoder including a head and a scale, with the head being provided on the fine movement stage 107 and the scale being provided on the slider 115. However, the height measuring device 113 may also be configured as a capacitance sensor.

[0019] Furthermore, the substrate stage WS, more specifically the fine movement stage 107, is provided with a bar mirror 110 that irradiates (reflects) light from an interferometer 112. The interferometer 112 is a length measuring device that measures the distance from the fixed base to the bar mirror 110, and measures the horizontal position of the substrate stage SS. Furthermore, in this embodiment, the interferometer 112 functions as a measurement unit (first measurement unit) that measures the tilt of the fine movement stage 107 with respect to the stage base 118 and acquires a tilt measurement value (first measurement value).

[0020] The projection optical system 102 includes optical elements such as lenses and projects a pattern of an original (not shown) onto a substrate ST held by a substrate stage SS. In this embodiment, the direction along an optical axis 101 of the projection optical system 102 (optical axis direction) is defined as the vertical direction (Z direction).

[0021] The focus measurement instrument FM includes, for example, a light projecting unit 104 that projects measurement light onto the surface (substrate surface) of the substrate ST held by the substrate stage WS, and a light receiving unit 105 that receives the measurement light reflected by the surface of the substrate ST. The focus measurement instrument FM is a measurement instrument (focus measurement unit) that measures the height 103 (height position) of the surface of the substrate ST held by the substrate stage WS, i.e., the position of the substrate ST in the vertical direction (optical axis direction). The measurement value obtained by the focus measurement instrument FM by measuring the position of the substrate ST in the vertical direction is called a focus measurement value Z focus Let's say.

[0022] The storage unit SU includes storage devices such as RAM, ROM, a hard disk, etc. The storage unit SU stores (contains) programs executed by the control unit CU, that is, programs for operating the exposure apparatus 1, various information and data, etc.

[0023] The control unit CU is composed of an information processing device (computer) including a CPU, memory, etc. The control unit CU operates the exposure apparatus 1 by comprehensively controlling each unit of the exposure apparatus 1 in accordance with a program stored in the storage unit SU. The control unit CU controls the exposure process (exposure method) that exposes the substrate ST (multiple shot areas on the substrate) using a step-and-repeat method. In this embodiment, the control unit CU controls focus drive in the exposure process to align the position of the substrate ST (substrate surface) in the optical axis direction of the projection optical system 102 with the focal plane 109 of the projection optical system 102 after step movement of the substrate stage SS. In other words, the control unit CU functions as a processing unit that performs processing related to focus drive.

[0024] The height (height position) and tilt (tilt attitude) of the substrate stage WS, specifically the height 106 of the fine movement stage 107 and the tilt 114 of the fine movement stage 107 relative to the slider 115, are acquired by the height measuring instrument 113 as described above. The measurement value acquired by the height measuring instrument 113 by measuring the height 106 of the fine movement stage 107 is referred to as a height measurement value Z enc The height measuring device 113 measures the tilt 114 of the fine movement stage 107 and obtains the measured value as the tilt measurement value θ enc(Second measurement value). The tilt measurement value θ enc indicates the angle formed between the slider surface of the slider 115 and the surface of the substrate ST.

[0025] Furthermore, as described above, the tilt (tilt attitude) of the substrate stage WS, specifically the tilt 108 of the fine movement stage 107 relative to the stage base 118, is also obtained by the interferometer 112. The measurement value obtained by the interferometer 112 measuring the tilt 108 of the fine movement stage 107 is referred to as the tilt measurement value θ Laser (First measurement value). The tilt measurement value θ Laser indicates an angle based on the stage base 118 (the focal plane 109 of the projection optical system 102).

[0026] Height measurement value Z enc , tilt measurement value θ enc and θ Laser The tilt control of the substrate stage SS can be measured using the fixed base of the apparatus as a reference, so the tilt measurement value θ Laser The fixed surface base of the apparatus is set to the side surface of the stage surface base 118 along the vertical direction.

[0027] Here, in the focus drive after the step movement of the substrate stage SS, in the prior art, the following equation (1) is used as a correction value for correcting the vertical position of the substrate stage SS. The correction value is also a height correction value of the substrate stage SS for aligning the surface of the substrate ST with the focal plane 109 of the projection optical system 102, with the fixed base of the exposure apparatus 1 as the reference. As shown in equation (1), the correction value is calculated by multiplying the focus measurement value Z obtained by the focus measurement instrument FM by focus and the height measurement value Z obtained by the height measuring device 113. enc and the tilt measurement value θ obtained by the interferometer 112. Laser The height measurement value Z enc and the measured tilt value θ Laser is a measurement value acquired at the timing when the focus measurement device FM is measuring the vertical height of the substrate ST (during the step movement of the substrate stage SS). Correction value = Z focus +Z enc +θ Laser ×DX...Formula (1) In equation (1), DX is the distance 121 between the rotation center axis 122 of the substrate stage SS and the optical axis 101 of the projection optical system 102.

[0028] However, in formula (1), an error occurs in correcting the vertical position of the substrate stage SS relative to the fixed base, depending on whether or not there is a pitching moment. A pitching moment is a moment that occurs when the thrust of a linear motor acts horizontally on the substrate stage SS, and the center of gravity of the substrate stage SS is not positioned on the line of action of the thrust. For example, if the distance 120 between the stage base 118 and the air pad 117 at the rotation center axis 122 of the substrate stage SS is defined as a distance Z gap1 Furthermore, the distance 119 between the stage base 118 and the air pad 117 on the optical axis 101 of the projection optical system 102 is defined as a distance Z gap2 In this case, the distance Z gap1 and distance Z gap2 The difference between these is the error caused by the pitching moment.

[0029] distance Z gap1 and distance Z gap2 The difference is calculated by dividing the angle 116 formed by the stage base 118 and the slider 115, which is changed by the pitching moment, by the tilt θ of the slider 115. AirGap is expressed by the following equation (2). Z gap1 -Z gap2 =θ AirGap ×DX...Formula (2) Tilt θ of slider 115 AirGap is the tilt measurement value θ obtained by the height measuring device 113 enc and the tilt measurement value θ obtained by the interferometer 112. Laser Using these, it is expressed by the following equation (3). θ AirGap =θ Laser -θ enc ...Equation (3) For equation (1), the distance Z gap1 and distance Zgap2 Considering equation (2) which expresses the difference (air gap of the substrate stage SS) between the above equations, the correction value for correcting the vertical position of the substrate stage SS is expressed by the following equation (4). Correction value = Z focus +Z enc +(θ Laser +θ AirGap )×DX...Equation (4) According to the correction value expressed by equation (4), even if a pitching moment occurs in the substrate stage SS and a fluctuation occurs in the air gap, it is possible to obtain a correction value based on the fixed base of the apparatus. As shown in equation (4), the correction value indicates the height up to the projection optical system 102 based on the stage base 118, and is the difference (θ AirGap ×DX).

[0030] In this manner, in this embodiment, the control unit CU calculates the tilt measurement value θ obtained during the step movement of the substrate stage SS. Laser and the measured tilt value θ enc The inclination θ of the slider 115 relative to the stage base 118 AirGap Then, the tilt θ of the slider 115 is calculated. AirGap Based on this, the correction value shown in equation (4) is calculated as the correction value for correcting the vertical position of the substrate stage SS during focus drive after the step movement of the substrate stage SS. Therefore, by using the correction value shown in equation (4) instead of the correction value shown in equation (3) during focus drive after the step movement of the substrate stage SS, highly accurate focus drive can be achieved, and focus accuracy can be improved.

[0031] The focus measurement unit FM measures the vertical position of the substrate ST and calculates the focus measurement value Z focus 2, a certain measurement period T1 is required to obtain the horizontal position (distance DX) of the substrate stage SS, the height (tilt measurement value θ enc ) and the tilt (θ AirGap) is a timing chart showing the correction value shown in the formula (4). AirGap is the tilt measurement value θ obtained during the measurement period T1. Laser and the measured tilt value θ enc It is preferable to use the average of the differences between these (averaging over the measurement period T1). This makes it possible to correct the vertical position of the substrate stage SS with higher precision during focus drive.

[0032] In the explanation so far, when no pitching moment is generated in the substrate stage SS, the tilt θ of the slider 115 AirGap However, in general, even if no pitching moment is generated on the substrate stage SS, the tilt θ of the slider 115, which serves as the reference, AirGap The tilt θ of the slider 115 as a reference is not zero. AirGap will be a different value for each horizontal position of the substrate stage SS, depending on the planar shape of the stage surface plate 118 and fluctuations in the air pressure of the air pads 117. Therefore, in order to more accurately determine the correction value for correcting the vertical position of the substrate stage SS during focus drive, it is preferable to use the tilt of the slider 115 in a static state where no pitching moment is applied to the substrate stage SS as the reference. An example of a static state where no pitching moment is applied to the substrate stage SS is a state where the substrate stage SS is settled.

[0033] Therefore, the inclination θ of the slider 115 AirGap The reference slope θ AirGapBase Then, the correction value for correcting the vertical position of the substrate stage SS is expressed by the following equation (5). Correction value = Z focus +Z enc +(θ Laser +θ AirGap -θ AirGapBase )×DX...Equation (5) Here, when no pitching moment is generated in the substrate stage SS, the tilt measurement value acquired by the interferometer 112 is used as the reference tilt measurement value θ LaserBaseThe tilt measurement value acquired by the height measuring device 113 is set as the reference tilt measurement value θ encBase In this case, the reference tilt θ AirGapBase is the reference tilt measurement value θ as shown in the following equation (6). LaserBase and the reference tilt measurement value θ encBase It is calculated as the difference (reference difference) between θ AirGapBase =θ LaserBase -θ encBase ...Equation (6) In this way, the tilt (angle 116) of the slider 115 is expressed as the tilt measurement value θ Laser and the measured tilt value θ enc The difference θ AirGap and θ LaserBase and the reference tilt measurement value θ encBase The reference difference θ AirGapBase By using the correction value shown in equation (5) (and equation (6)), even if the angle 116 formed by the stage base 118 and the slider 115 is a different value for each horizontal position of the substrate stage SS, the vertical position of the substrate stage SS can be corrected with high precision.

[0034] In addition, the reference difference θ AirGapBase is preferably generated in advance as map data and stored in the storage unit SU. The map data is a table showing the relationship between each of a plurality of positions of the substrate stage SS in the horizontal direction and the reference difference θ AirGapBase By referencing the map data stored in the memory unit SU, it is possible to determine the correction value shown in equation (5), and the vertical position of the substrate stage SS can be corrected with high precision during focus drive.

[0035] When generating the map data, the reference tilt measurement value θ is set in a state where no pitching moment is generated, that is, when the substrate stage SS is settled. LaserBase and the reference tilt measurement value θ encBaseTherefore, in this embodiment, the control unit determines whether the substrate stage SS is in a settled state, and if the substrate stage SS is in a settled state, acquires the reference difference θ AirGapBase is stored in the storage unit SU.

[0036] The multiple horizontal positions of the substrate stage SS can be assigned to multiple grids (for example, shot areas) that divide the movement range in which the substrate stage SS moves step by step. In this way, the multiple horizontal positions of the substrate stage SS are positions within a grid that is defined according to the step size of the step movement of the substrate stage SS (the movement distance corresponding to one step movement). In this case, when referencing the map data stored in the storage unit SU, the reference difference θ that is stored in association with the grid that is closest to the current position of the substrate stage SS is used. AirGapBase The number of divisions into the grid can be set arbitrarily depending on the movement range of the substrate stage SS, the step size of the step movement, the storage capacity (area) of the storage unit SU, the required accuracy required for focus drive, and the like.

[0037] Referring to FIG. 3, the reference difference θ AirGapBase In the servo control of the substrate stage SS, the reference difference θ AirGapBase 10 is a flowchart illustrating a method for acquiring the

[0038] In S301, it is determined whether the substrate stage SS is in a settled state (settled state). As described above, this is determined by the reference difference θ AirGapBase In order to obtain this, the reference tilt measurement value θ must be obtained when no pitching moment is occurring. LaserBase and the reference tilt measurement value θ encBaseThis is because it is necessary to acquire the above information. For example, if the substrate stage SS is controlled by a position servo, it is determined whether the substrate stage SS is in a settled state based on the position error of the substrate stage SS. For the position error of the substrate stage SS, for example, the maximum absolute value, average value, or variance of the position error over a certain period of servo control of the substrate stage SS may be used. If the position error of the substrate stage SS is equal to or less than the threshold value, it is determined that the substrate stage SS is in a settled state, and the process proceeds to S302. On the other hand, if the position error of the substrate stage SS is greater than the threshold value, it is determined that the substrate stage SS is not in a settled state (the substrate stage SS has not settled), and the process exits the servo control loop.

[0039] In S302, the reference tilt measurement value θ obtained by the interferometer 112 LaserBase and the reference tilt measurement value θ obtained by the height measuring device 113 encBase Accumulate.

[0040] In S303, the reference tilt measurement value θ accumulated in S302 is LaserBase and θ encBase Determine whether the reference tilt measurement value θ has reached a predetermined number of samples. LaserBase and θ encBase If the number of samples has not yet reached the predetermined number, the servo control loop is terminated. LaserBase and θ encBase When the number of samples reaches the predetermined number, the process proceeds to S304.

[0041] In S304, the reference tilt measurement value θ accumulated in S302 is LaserBase and θ encBase Specifically, the map data stored in the storage unit SU is updated based on the reference tilt measurement value θ of the predetermined number of samples accumulated in S302. LaserBase and θ encBase The standard difference θ AirGapBase Then, the reference difference θ AirGapBaseThe map data stored in the storage unit SU is updated. LaserBase and θ encBase From the above, the reference difference θ AirGapBase By calculating the above, the influence of noise can be reduced.

[0042] Referring to FIG. 4, the reference difference θ AirGapBase Another method for obtaining the reference difference θ AirGapBase 10 is a flowchart illustrating a method for acquiring the

[0043] Because the exposure apparatus 1 exposes the substrate ST using a step-and-repeat method, the substrate stage SS moves stepwise and then settles into a certain state before the exposure process is performed. Therefore, as shown in FIG. 4, in S401, the exposure state of the substrate ST—specifically, whether the substrate ST is currently being exposed—is determined, thereby indirectly determining whether the substrate stage ST is in a settled state. For example, if the intensity of the exposure light detected by a photodiode provided in the exposure apparatus 1 is equal to or greater than a threshold, it is determined that the substrate ST is currently being exposed, and the process proceeds to S402. On the other hand, if the intensity of the exposure light detected by the photodiode provided in the exposure apparatus 1 is less than the threshold, it is determined that the substrate ST is not currently being exposed, and the servo control loop is exited. By determining whether exposure is currently being performed in this way, special calculation processing for determining whether the substrate stage ST is currently in a settled state is not required, thereby reducing the calculation load compared to the method shown in FIG. 4. Note that S402 to S404 are similar to S302 to S304, and therefore detailed description thereof will be omitted here.

[0044] Up until now, in focus driving, the tilt θ of the slider 115 AirGap The difference between the vertical target position of the substrate stage SS caused by the fluctuation of the focus measurement value Z focus In this case, the correction value is added to a target value that indicates the target position in the vertical direction of the substrate stage SS during focus drive.

[0045] On the other hand, the tilt θ of the slider 115 AirGap The difference between the vertical target position of the substrate stage SS caused by the fluctuation of the height may be used as the control deviation of the height of the substrate stage SS, as shown in FIG. 5. In this case, the correction value is input as the deviation from the target value of the servo control of the substrate stage SS during focus drive. FIG. 5 is a control block diagram of the vertical position of the substrate stage SS. In FIG. 5, a signal 507 is a signal representing the tilt measurement value θ obtained by the height measuring device 113. enc and the tilt measurement value θ obtained by the interferometer 112 Laser The tilt θ of the slider 115 is the difference between AirGap The signal 508 indicates the tilt θ of the slider 115. AirGap and the horizontal position (distance DX) of the substrate stage SS acquired by the interferometer 112. A signal 508 is input to the compensator 501 as the deviation of the substrate stage SS from the target value.

[0046] Second Embodiment In the first embodiment, when a pitching moment occurs in the substrate stage SS, the fluctuation of the air gap between the stage base 118 and the slider 115 is calculated based on the tilt θ AirGap In the above, the case where correction is performed according to the above has been described.

[0047] In this embodiment, as shown in FIG. 6, the tilt measurement value θ enc and the tilt measurement value θ obtained by the interferometer 112 Laser From this, the timing T2 at which the pitching moment becomes zero is estimated. Then, at timing T2, the focus measurement device FM measures the vertical position of the substrate ST, thereby enabling focus drive to be performed without being affected by variations in the air gap. FIG. 6 shows the horizontal position (distance DX) of the substrate stage SS, the horizontal acceleration of the substrate stage SS, and the tilt (θ AirGap ) is a diagram showing a timing chart of

[0048] Specifically, the tilt measurement value θenc and the measured tilt value θ Laser The tilt θ of the slider 115 is the difference between AirGap The focus measurement unit FM is controlled so as to measure the vertical position of the substrate ST at the timing when the reference tilt measurement value θ LaserBase and the reference tilt measurement value θ encBase The reference difference θ AirGapBase The focus measurement unit FM may be controlled so as to measure the vertical position of the substrate ST at the timing when (the absolute value of) becomes equal to or less than the threshold value. This makes it possible to achieve highly accurate focus driving and improve focus accuracy even when a pitching moment occurs in the substrate stage SS and fluctuations occur in the air gap.

[0049] <Third embodiment> The method for manufacturing an article according to an embodiment of the present invention is suitable for manufacturing articles such as semiconductor devices, flat panel displays, liquid crystal display devices, and MEMS. This manufacturing method includes the steps of exposing a substrate coated with a photosensitive agent using the exposure apparatus 1 (exposure method) described above and developing the exposed photosensitive agent. The developed photosensitive agent pattern is then used as a mask to perform etching and ion implantation processes on the substrate, forming a circuit pattern on the substrate. These exposure, development, etching, and other processes are repeated to form a circuit pattern consisting of multiple layers on the substrate. In subsequent processes, the substrate on which the circuit pattern has been formed is diced (processed), followed by chip mounting, bonding, and inspection. This manufacturing method may also include other well-known processes (such as oxidation, film formation, vapor deposition, doping, planarization, and resist stripping). The method for manufacturing an article according to this embodiment is advantageous over conventional methods in at least one of the performance, quality, productivity, and production cost of the article.

[0050] The disclosure of the present specification includes the following exposure apparatus, exposure method, and method for manufacturing an article.

[0051] (Item 1) An exposure apparatus that exposes a substrate using a step-and-repeat method, a stage for holding the substrate, the stage including a slider that moves on a surface plate and a fine movement stage that adjusts the tilt of the substrate on the slider; a projection optical system that projects a pattern of an original onto the substrate held by the stage; a first measurement unit that measures the tilt of the fine movement stage with respect to the surface plate to obtain a first measurement value; a second measurement unit that measures the tilt of the fine movement stage with respect to the slider and acquires a second measurement value; a processing unit that calculates an inclination of the slider with respect to the base from the first measurement value and the second measurement value acquired during the step movement of the stage, and calculates a correction value, based on the inclination of the slider, for correcting the position of the stage in the optical axis direction during focus drive for aligning the position of the substrate in the optical axis direction with a focal plane of the projection optical system after the step movement of the stage; An exposure apparatus comprising:

[0052] (Item 2) 2. The exposure apparatus according to item 1, wherein the processing unit determines the inclination of the slider relative to the base as the difference between the first measurement value and the second measurement value acquired during step movement of the stage.

[0053] (Item 3) 3. The exposure apparatus according to item 2, wherein the processing unit calculates the correction value based on the difference and the horizontal position of the stage when the first measurement value and the second measurement value were acquired during step movement of the stage.

[0054] (Item 4) 4. The exposure apparatus according to any one of items 1 to 3, wherein the correction value includes a difference between a target position of the stage in the optical axis direction during the focus drive.

[0055] (Item 5) 5. The exposure apparatus according to any one of items 1 to 4, wherein the correction value is added to a target value that indicates a target position of the stage in the optical axis direction during focus drive.

[0056] (Item 6) a focus measurement unit that measures the position of the substrate held by the stage in the optical axis direction, 6. The exposure apparatus according to item 5, wherein the processing unit calculates, as the tilt of the slider relative to the base, an average of the differences between the first measurement value and the second measurement value acquired during a measurement period in which the focus measurement unit measures the position of the substrate in the optical axis direction during step movement of the stage.

[0057] (Item 7) 5. The exposure apparatus according to any one of items 1 to 4, wherein the correction value is input as a deviation from a target value of servo control of the stage in the focus drive.

[0058] (Item 8) 8. The exposure apparatus according to any one of items 1 to 7, wherein the processing unit calculates, as the tilt of the slider relative to the base, the difference between the difference between the first measurement value and the second measurement value acquired during step movement of the stage, and a reference difference between the first measurement value and the second measurement value acquired when the stage is settled.

[0059] (Item 9) the processing unit calculates a reference difference between the first measurement value and the second measurement value acquired while the stage is settled, for each of a plurality of positions in the horizontal direction of the stage; further comprising a storage unit that stores the reference difference for each of the plurality of positions; 9. The exposure apparatus according to item 8,

[0060] (Item 10) 9. The exposure apparatus according to item 8, wherein the processing unit determines whether the stage is in a settled state based on a position deviation of the stage in servo control of the stage.

[0061] (Item 11) 9. The exposure apparatus according to item 8, wherein the processing unit determines whether the stage is in a settled state based on the exposure state of the substrate.

[0062] (Item 12) 10. The exposure apparatus according to item 9, wherein the plurality of positions are positions within a grid that is defined according to a step size of the step movement of the stage.

[0063] (Item 13) the first measurement unit includes an interferometer, The second measurement unit includes an encoder or a capacitance sensor. 13. The exposure apparatus according to any one of items 1 to 12, wherein:

[0064] (Item 14) 14. The exposure apparatus according to any one of items 1 to 13, wherein the stage includes an air pad that levitates the slider from the base.

[0065] (Item 15) An exposure apparatus that exposes a substrate using a step-and-repeat method, a stage for holding the substrate, the stage including a slider that moves on a surface plate and a fine movement stage that adjusts the tilt of the substrate on the slider; a projection optical system that projects a pattern of an original onto the substrate held by the stage; a first measurement unit that measures the tilt of the fine movement stage with respect to the surface plate to obtain a first measurement value; a second measurement unit that measures the tilt of the fine movement stage with respect to the slider and acquires a second measurement value; a focus measurement unit that measures the position of the substrate held by the stage in the optical axis direction of the projection optical system; a control unit that controls the focus measurement unit so that the focus measurement unit measures the position of the substrate in the optical axis direction at a timing when a difference between the first measurement value and the second measurement value acquired during step movement of the stage becomes equal to or smaller than a threshold value; An exposure apparatus comprising:

[0066] (Item 16) An exposure method for exposing a substrate held by a stage including a slider that moves on a surface plate and a fine-motion stage that adjusts the tilt of the substrate on the slider, by a step-and-repeat method, comprising: measuring the tilt of the fine movement stage with respect to the surface plate to obtain a first measurement value; measuring the tilt of the fine movement stage relative to the slider to obtain a second measurement value; determining an inclination of the slider with respect to the base from the first measurement value and the second measurement value acquired during the step movement of the stage, and determining, based on the inclination of the slider, a correction value for correcting the position of the stage in the optical axis direction during focus drive for aligning the position of the substrate in the optical axis direction with a focal plane of a projection optical system that projects a pattern of an original after the step movement of the stage; An exposure method comprising:

[0067] (Item 17) Item 17. Exposing a substrate using the exposure method according to Item 16; developing the exposed substrate; manufacturing an article from the developed substrate; A method for manufacturing an article, comprising:

[0068] The 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. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0069] 1: exposure device 102: projection optical system 107: fine stage 112: interferometer 113: height measuring instrument 115: slider ST: substrate SS: substrate stage CU: control unit

Claims

1. An exposure apparatus that exposes a substrate by a step-and-repeat method, a stage for holding the substrate, the stage including a slider that moves on a surface plate and a fine movement stage that adjusts the tilt of the substrate on the slider; a projection optical system that projects a pattern of an original onto the substrate held by the stage; a first measurement unit that measures the tilt of the fine movement stage with respect to the surface plate to obtain a first measurement value; a second measurement unit that measures the tilt of the fine movement stage with respect to the slider and acquires a second measurement value; a processing unit that calculates an inclination of the slider with respect to the base from the first measurement value and the second measurement value acquired during the step movement of the stage, and calculates a correction value, based on the inclination of the slider, for correcting the position of the stage in the optical axis direction during focus drive for aligning the position of the substrate in the optical axis direction with a focal plane of the projection optical system after the step movement of the stage; An exposure apparatus comprising:

2. 2. The exposure apparatus according to claim 1, wherein the processing unit determines, as the tilt of the slider relative to the base, a difference between the first measurement value and the second measurement value acquired during step movement of the stage.

3. 3. The exposure apparatus according to claim 2, wherein the processing unit calculates the correction value based on the difference and the horizontal position of the stage when the first measurement value and the second measurement value were acquired during step movement of the stage.

4. 2. The exposure apparatus according to claim 1, wherein the correction value includes a difference between a target position of the stage in the optical axis direction during the focus drive.

5. 2. The exposure apparatus according to claim 1, wherein the correction value is added to a target value that indicates a target position of the stage in the optical axis direction during focus drive.

6. a focus measurement unit that measures the position of the substrate held by the stage in the optical axis direction, 6. The exposure apparatus according to claim 5, wherein the processing unit calculates, as the inclination of the slider relative to the base, an average of the differences between the first measurement value and the second measurement value acquired during a measurement period in which the focus measurement unit measures the position of the substrate in the optical axis direction during step movement of the stage.

7. 2. The exposure apparatus according to claim 1, wherein the correction value is input as a deviation from a target value of servo control of the stage in the focus drive.

8. 2. The exposure apparatus according to claim 1, wherein the processing unit calculates, as the inclination of the slider relative to the base, the difference between the difference between the first measurement value and the second measurement value acquired during step movement of the stage and a reference difference between the first measurement value and the second measurement value acquired when the stage is settled.

9. the processing unit calculates a reference difference between the first measurement value and the second measurement value acquired while the stage is settled, for each of a plurality of positions in the horizontal direction of the stage; further comprising a storage unit that stores the reference difference for each of the plurality of positions; 9. An exposure apparatus according to claim 8.

10. 9. The exposure apparatus according to claim 8, wherein the processing unit determines whether the stage is in a settled state based on a position deviation of the stage in servo control of the stage.

11. 9. The exposure apparatus according to claim 8, wherein the processing unit determines whether the stage is in a settled state based on an exposure state of the substrate.

12. 10. The exposure apparatus according to claim 9, wherein the plurality of positions are positions within a grid that is defined according to a step size of step movement of the stage.

13. the first measurement unit includes an interferometer, The second measurement unit includes an encoder or a capacitance sensor.

2. An exposure apparatus according to claim 1.

14. 2. An exposure apparatus according to claim 1, wherein the stage includes an air pad that levitates the slider from the surface plate.

15. An exposure apparatus that exposes a substrate by a step-and-repeat method, a stage for holding the substrate, the stage including a slider that moves on a surface plate and a fine movement stage that adjusts the tilt of the substrate on the slider; a projection optical system that projects a pattern of an original onto the substrate held by the stage; a first measurement unit that measures the tilt of the fine movement stage with respect to the surface plate to obtain a first measurement value; a second measurement unit that measures the tilt of the fine movement stage with respect to the slider and acquires a second measurement value; a focus measurement unit that measures the position of the substrate held by the stage in the optical axis direction of the projection optical system; a control unit that controls the focus measurement unit so that the focus measurement unit measures the position of the substrate in the optical axis direction at a timing when a difference between the first measurement value and the second measurement value acquired during step movement of the stage becomes equal to or smaller than a threshold value; An exposure apparatus comprising:

16. An exposure method for exposing a substrate held by a stage including a slider that moves on a surface plate and a fine-motion stage that adjusts the tilt of the substrate on the slider, by a step-and-repeat method, comprising: measuring the tilt of the fine movement stage with respect to the surface plate to obtain a first measurement value; measuring the tilt of the fine movement stage relative to the slider to obtain a second measurement value; determining an inclination of the slider with respect to the base from the first measurement value and the second measurement value acquired during the step movement of the stage, and determining, based on the inclination of the slider, a correction value for correcting the position of the stage in the optical axis direction during focus drive for aligning the position of the substrate in the optical axis direction with a focal plane of a projection optical system that projects a pattern of an original after the step movement of the stage; An exposure method comprising:

17. exposing a substrate using the exposure method according to claim 16; developing the exposed substrate; manufacturing an article from the developed substrate; A method for manufacturing an article, comprising:

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