The present invention relates to a processing apparatus, a measurement method, and an article manufacturing method.
As pattern forming apparatuses for forming a pattern on a substrate, an imprint apparatus and an exposure apparatus are known. The imprint apparatus brings an imprint material on a substrate into contact with a mold, and cures the imprint material, thereby forming a pattern of the imprint material. The exposure apparatus transfers a pattern of an original to a photoresist applied to a substrate to form a latent image, and develops the latent image, thereby forming a resist pattern.
In the imprint apparatus, it is important to control the relative posture between the surface of the substrate and the pattern surface of the mold when bringing the imprint material on the substrate into contact with the pattern surface of the mold. If the relative posture is inappropriate, fall of the pattern formed on the substrate, a failure of filling of the imprint material in a concave portion of the mold or in the space between the substrate and the mold, or the like may occur. In the exposure apparatus, to control the shot region of the substrate within the focal depth of a projection optical system, it is important to make the surface of the substrate parallel to the imaging plane of the projection optical system.
Japanese Patent Laid-Open No. 2006-156508 discloses a technique of measuring the thickness distribution of a substrate and the height distribution of a holding surface for holding the substrate in advance in an exposure apparatus using a projection optical system and obtaining the height distribution of the surface of the substrate held by the holding surface based on the measurement results. Japanese Patent Laid-Open No. 2018-22114 discloses a technique of measuring the surface of a substrate in two directions different from each other in an exposure apparatus using a projection optical system, thereby shortening the time needed to measure the height distribution of the surface of the substrate.
A movable body on which a substrate holder for holding a substrate is mounted can be driven and positioned in a state in which the movable body is floated by an air pressure on a guide surface. The air pressure can be provided from a plant facility to the pattern forming apparatus. If the air pressure varies, the height of the substrate may vary. In processing of measuring the shape of a substrate by measuring the height of the substrate at a plurality of measurement points of the measurement target region of the substrate, if the air pressure varies, the influence of the pressure variation may appear in the measurement result.
The present invention provides a technique advantageous in reducing measurement errors caused by a variation of an air pressure.
One of aspects of the present invention provides a processing apparatus comprising: a height measurement device configured to perform first measurement of measuring a height of at least one measurement point of a measurement target region and second measurement of measuring heights of a plurality of measurement points of the measurement target region; a pressure measurement device configured to measure an air pressure that influences results of the first measurement and the second measurement by the height measurement device; and a calculator configured to obtain shape information representing a shape of the measurement target region by correcting the result of the second measurement by the height measurement device based on the result of the first measurement by the height measurement device and a result of measurement of the air pressure by the pressure measurement device.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Hereinafter, embodiments will be described in detail with reference to the attached drawings. Note, the following embodiments are not intended to limit the scope of the claimed invention. Multiple features are described in the embodiments, but limitation is not made to an invention that requires all such features, and multiple such features may be combined as appropriate. Furthermore, in the attached drawings, the same reference numerals are given to the same or similar configurations, and redundant description thereof is omitted.
The present invention can be applied to various processing apparatuses in which a measurement result of the height or shape of a measurement target region is influenced by a variation of an air pressure. Such a processing apparatus can be, for example, a pattern forming apparatus such as an imprint apparatus or an exposure apparatus. Alternatively, such a processing apparatus can be, for example, a coating apparatus, an etching apparatus, or a cleaning apparatus. An example in which the present invention is applied to an imprint apparatus will be described below. It is obvious that the present invention can be applied to another processing apparatus based on the following explanation.
The imprint apparatus 101 performs imprint processing of forming the pattern of the imprint material on the substrate 1 using the mold 41. The imprint processing can include a contact step, a curing step executed after the contact step, and a separation step executed after the curing step. In the contact step, the imprint material on a portion of the shot region of the substrate 1 can be brought into contact with the pattern surface of the mold 41, and after that, the contact region between the imprint material and the pattern surface can be expanded to the whole shot region. In the curing step, the imprint material can be cured in a state in which the imprint material on the shot region of the substrate 1 and the pattern surface of the mold 41 are in contact. In the separation step, the cured product of the imprint material on the shot region of the substrate 1 and the pattern surface of the mold 41 can be separated. The imprint apparatus 101 may include a dispenser configured to arrange the imprint material on the substrate 1. In this case, the imprint processing can include an arrangement step of arranging the imprint material on the substrate 1 by the dispenser before the contact step.
The imprint apparatus 101 can include a movable body 21 floated by an air pressure above a guide surface GS, a substrate holder 11 mounted on the movable body 21, and a substrate driving mechanism 29 that drives the substrate 1 by driving the movable body 21. The substrate holder 11 can hold the substrate 1 by vacuum chucking, electrostatic chucking, mechanical chucking, or the like. The movable body 21 includes an injector 22 (an air bearing or an air guide) and can be driven in horizontal directions (X and Y directions) by the substrate driving mechanism 29 while maintaining a state in which air is injected via the injectors 22, and the movable body 21 floats above the guide surface GS. The floating amount can be, for example, several μm. The air can be, for example, clean dry air. The air can be supplied from, for example, a plant facility in which the imprint apparatus 101 is installed to the imprint apparatus 101 via a supply path 83. The imprint apparatus 101 can include, for example, a pressure measurement device 80 that measures the pressure of air supplied to the injectors 22 via the supply path 83. The pressure measurement device 80 may be arranged, for example, in the movable body 21, may be arranged near a connecting portion that connects the imprint apparatus 101 and the plant facility, or may be arranged at another position. The imprint apparatus 101 can include a mold holder 51 that holds the mold 41, and a mold driving mechanism 61 that drives the mold 41 by driving the mold holder 51.
The imprint apparatus 101 may include a substrate conveying mechanism 31 that loads the substrate 1 onto the substrate holding surface of the substrate holder 11 or unloads the substrate 1 on the substrate holding surface to the outside of the imprint apparatus 101. The substrate conveying mechanism 31 may include a rotation mechanism that rotates the substrate 1 about an axis (an axis parallel to the vertical direction) orthogonal to its surface. The rotation mechanism may be implemented by, for example, rotating the link mechanism of a plurality of robot hands, may be implemented by rotating the robots themselves, or may be implemented by another mechanism. The rotation mechanism may measure the rotation angle using an orientation marker such as a notch provided on the outer peripheral portion of the substrate 1 or may measure the rotation angle using an encoder or the like.
The imprint apparatus 101 can include a height measurement device 81 that measures the height (the position in the Z direction) of the measurement target region of the substrate 1. The height measurement device 81 can measure the heights of a plurality of measurement points in the measurement target region. The measurement target region can include at least a part of the surface of the substrate 1. In an example, the position in the horizontal direction (X and Y directions) at which the height is measured by the height measurement device 81 can be adjusted by adjusting the position of the substrate 1 in the horizontal direction by the substrate driving mechanism 29. The height measurement device 81 can be, for example, a laser displacement gauge or a spectral interferometer, but may be a measurement device of another type. The height measurement device 81 can be configured to, for example, measure the distance (for example, the optical path length difference) between a reference position and the measurement target region of the substrate 1. The height measurement device 81 can be configured or controlled to perform first measurement of measuring the height of at least one measurement point of the measurement target region of the substrate 1 and second measurement of measuring the heights of a plurality of measurement points of the measurement target region of the substrate 1.
The imprint apparatus 101 can include a calculator 91. The calculator 91 can be formed by, for example, a PLD (an abbreviation of Programmable Logic Device) such as an FPGA (an abbreviation of Field Programmable Gate Array) or an ASIC (an abbreviation of Application Specific Integrated Circuit), or a general-purpose or dedicated computer incorporating a program, or a combination of some or all of these components. The calculator 91 may form the whole or a part of a controller 90 that controls the imprint apparatus 101. The calculator 91 can perform a calculation of obtaining shape information representing the shape of the measurement target region of the substrate 1 by correcting the result of second measurement by the height measurement device 81 based on the result of first measurement by the height measurement device 81 and the result of measurement by the pressure measurement device 80.
A pressure variation of air provided by the plant facility depends on the performance of a pump used to supply the air and is periodical. The pressure variation width of the air provided by the plant facility changes depending on the plant facility, and the air pressure can have a variation width of, for example, several tens of kPa. In a semiconductor manufacturing apparatus, air supplied from a plant can be controlled to a desired pressure value or a pressure variation width using a pressure control valve or the like and used. If accurate pressure control is required, the pressure variation width can be suppressed to several kPa using a precision pressure control valve or the like.
In the imprint apparatus 101, the contact step can be executed in a state in which the mold 41 is tilted by the mold driving mechanism 61 such that the substrate surface and the pattern surface of the mold 41 become parallel in each shot region. Hence, the imprint apparatus 101 may be, for example, required to measure the height distribution (shape) of the measurement target region of the substrate 1 on a nanometer order. However, in the arrangement in which the floating amount of the movable body 21 is influenced by the variation of the air pressure provided from the plant facility, even if the pressure variation is suppressed to several kPa by a precision pressure control valve, the floating amount may vary within the range of several tens of nanometers. Additionally, in some cases, the structure that supports the movable body 21 or the height measurement device 81 is also floated by an air mount system to relax the influence of a vibration component from the floor. In this case, the structure may also be influenced by the pressure variation of the air provided from the plant facility. Also, even if a height measurement device 82 and the movable body 21 are supported by different structures in consideration of a vibration caused by driving of the movable body 21, one of these may be influenced by the pressure variation of the air supplied from the plant facility.
ΔZw1_S0=K0×ΔPw1_S0 (1)
holds.
The height of the movable body 21 that almost maintains the horizontal posture varies in accordance with equation (1). Hence, letting Kw be the correction coefficient used to correct the height measured by the height measurement device 81, the correction coefficient Kw used when the height is measured only at the origin S0 can be given by
Kw=K0 (2)
ΔZw1_S1=K1×ΔPw1_S1 (3)
ΔZw1_S2=K2×ΔPw1_S2 (4)
ΔZw1_S3=K3×ΔPw1_S3 (5)
ΔZw1_S4=K4×ΔPw1_S4 (6)
Since the height of the movable body 21 changes following the variation of the air pressure in accordance with equations (1), (3), (4), (5), and (6), the correction coefficient Kw used when the heights of the five measurement points S0 to S4 are measured can be given by
Kw=(K4−K2)÷(K4_x−K2_x)×X+(K3−K1)÷(K3_y−K1_y)×Y+K0 (7)
where K2_x and K4_x represent the x-coordinates of the measurement points S2 and S4, and K1_y and K3_y represent the y-coordinates of the measurement points S1 and S3. In addition, X and Y represent an arbitrary point on the substrate 1 on the XY coordinate system.
In this example, the measurement points are set to the origin S0, the points S2 and S4 on the X-axis, and the points S1 and S3 on the Y-axis. However, the number and positions of measurement points are not limited to this example, and arbitrary points on the substrate 1 can be set to measurement points. In addition, the first measurement by the height measurement device 81 and the air pressure measurement by the pressure measurement device 80 are preferably performed at least for one period of the variation of the air pressure.
Zwt1(x,y)=Zw2(x,y)−Kw×(Pw2(x,y)−Pw2(0,0)) (8)
where Pw2(0, 0) is a pressure measured by the pressure measurement device 80 when measuring the height of the origin (0, 0) of the XY coordinate system on the substrate 1. However, an arbitrary point on the substrate 1 can be set to the reference point. In addition, the arrangement of the plurality of measurement points in the second measurement by the height measurement device 81 (or the scanning method of the substrate 1) may be determined such that the measurement points are arranged on each of a plurality of lines parallel to the X direction. Alternatively, the arrangement of the plurality of measurement points in the second measurement by the height measurement device 81 (or the scanning method of the substrate 1) may be determined such that the measurement points are arranged on each of a plurality of lines in an oblique direction with respect to the X or Y direction. Alternatively, the arrangement of the plurality of measurement points in the second measurement by the height measurement device 81 (or the scanning method of the substrate 1) may be determined such that the plurality of measurement points are arranged on a spiral line.
In step S501, the controller 90 controls execution of first measurement of measuring the height of at least one measurement point of the measurement target region of the substrate 1 by the height measurement device 81 and air pressure measurement of measuring the air pressure by the pressure measurement device 80 in synchronism with the first measurement. The first measurement may be performed for a plurality of measurement points of the measurement target region of the substrate 1. As for the number of times of measurement (sampling) at each measurement point, the measurement is preferably performed at least for one period of the variation of the air pressure measured by the pressure measurement device 80.
In step S502, the controller 90 or the calculator 91 calculates or determines the correction coefficient Kw based on the results of the first measurement and the air pressure measurement in step S501. In step S503, the controller 90 controls execution of second measurement of measuring the heights of a plurality of measurement points of the measurement target region of the substrate 1 by the height measurement device 81 and air pressure measurement of measuring the air pressure by the pressure measurement device 80 in synchronism with the second measurement. In step S504, the controller 90 or the calculator 91 corrects the result of the second measurement by the height measurement device 81 based on the correction coefficient Kw calculated or determined in step S502, thereby obtaining shape information representing the shape of the measurement target region of the substrate 1. In other words, in step S504, the controller 90 or the calculator 91 corrects the result of the second measurement by the height measurement device 81 based on the result of the first measurement by the height measurement device 81 and the result of the air pressure measurement by the pressure measurement device 80. Accordingly, the controller 90 or the calculator 91 obtains shape information representing the shape of the measurement target region of the substrate 1.
In step S505, the controller 90 can determine whether the shape information (height distribution) obtained in step S504 is allowable. This determination can be done by, for example, judging whether an index (for example, the maximum height difference of the measurement target region of the substrate 1) obtained from the shape information obtained in step S504 falls within a preset allowable range. If the shape information (height distribution) obtained in step S504 is allowable, the controller 90 can end the measurement processing shown in
Step S501 is an example of the first step of performing first measurement of measuring the height of at least one measurement point of the measurement target region by the height measurement device 81 and air pressure measurement of measuring, by the pressure measurement device 80, the air pressure that influences the result of the first measurement. In the first step, the air pressure measurement can be performed in synchronism with the first measurement. Step S503 is an example of the second step of performing second measurement of measuring the heights of a plurality of measurement points of the measurement target region by the height measurement device 81. Steps S502 and S504 are an example of the third step of obtaining shape information representing the shape of the measurement target region by correcting the result obtained in the second step based on the result obtained in the first step. In the third step, the shape information can be obtained by correcting the result of the second measurement based on the correction coefficient determined in step S502 based on the result of the first step and the result of the air pressure measurement performed in synchronism with the second measurement.
The second embodiment will be described below with reference to
The frequency Fpw1_1 can be regarded as the main frequency of the variation of the air pressure. The frequency Fzw1 can have various peaks depending on the arrangement of an imprint apparatus 101 in addition to the influence of the variation of the air pressure in the plant facility. For this reason, even if the frequency representing the peak is obtained by frequency analysis of the result of the first measurement by the height measurement device 81, it is impossible to discriminate whether the frequency is the frequency of the variation of the height caused by the variation of the air pressure. On the other hand, even if the frequency representing the peak is obtained by frequency analysis of the result of the air pressure measurement by the pressure measurement device 80, it is also impossible to discriminate whether the pressure variation at the frequency has an influence on the measurement result of the height of the measurement point of a substrate 1.
Hence, the calculator 91 can compare the main frequency Fpw1_1 of the variation of the air pressure measured by the pressure measurement device 80 with the frequencies of the plurality of peaks in the variation of the height measured by the height measurement device 81. As the result of the comparison, if one of the frequencies of the plurality of peaks in the variation of the height matches the main frequency Fpw1_1 of the variation of the air pressure, the frequency that matches the main frequency Fpw1_1 can be regarded as the frequency of the variation of the measurement result of the height caused by the variation of the air pressure.
Here, let Fw be the frequency that matches the main frequency Fpw1_1 of the variation of the air pressure in the frequencies Fzw1_1 of the plurality of peaks in the variation of the height measured by the height measurement device 81. Fw is given by
Fw=Fpw1_1 (9)
If none of the frequencies Fzw1_1 of the plurality of peaks in the variation of the height measured by the height measurement device 81 matches the main frequency Fpw1_1, it can be considered that the influence of the variation of the air pressure does not exist in the height measurement of the substrate 1. An example in which the origin S0 on the substrate 1 is set to the measurement point in the first measurement has been described here. However, the measurement point in the first measurement can arbitrarily be determined. In the second embodiment as well, the first measurement by the height measurement device 81 and the measurement of the air pressure by the pressure measurement device 80 are preferably performed at least for one period of the variation of the air pressure. If the period is shorter than one period, a high frequency component that cannot exist originally is added as the measurement result, and therefore, there may be a possibility that a desired result cannot be obtained.
The calculator 91 can perform frequency analysis of the measurement result of the height obtained by the second measurement by the height measurement device 81 and determine whether the component of the frequency Fw is included. If the component of the frequency Fw is included in the measurement result of the height obtained by the second measurement by the height measurement device 81, the calculator 91 can remove the component of the frequency Fw from a result Zw2(x, y) of the measurement in the second measurement by the height measurement device 81. This makes it possible to obtain a height distribution Zwt1(x, y) in the measurement target region of the substrate 1, from which the variation of the air pressure is removed.
In step S801, the controller 90 controls execution of first measurement of measuring the height of at least one measurement point of the measurement target region of the substrate 1 by the height measurement device 81 and air pressure measurement of measuring the air pressure by the pressure measurement device 80 in synchronism with the first measurement. The first measurement may be performed for a plurality of measurement points of the measurement target region of the substrate 1. As for the number of times of measurement (sampling) at each measurement point, the measurement is preferably performed at least for one period of the variation of the air pressure measured by the pressure measurement device 80.
In step S802, the controller 90 or the calculator 91 calculates or determines the frequency Fw of the variation of the air pressure by frequency analysis based on the results of the first measurement and the air pressure measurement in step S801. In step S803, the controller 90 controls execution of second measurement of measuring the heights of a plurality of measurement points of the measurement target region of the substrate 1 by the height measurement device 81. In step S804, the controller 90 or the calculator 91 corrects the result of the second measurement by the height measurement device 81 based on the component of the frequency Fw calculated or determined in step S802, thereby obtaining shape information representing the shape of the measurement target region of the substrate 1. In other words, in step S804, the controller 90 or the calculator 91 corrects the result of the second measurement by the height measurement device 81 based on the result of the first measurement by the height measurement device 81 and the result of the air pressure measurement by the pressure measurement device 80. Accordingly, the controller 90 or the calculator 91 obtains shape information representing the shape of the measurement target region of the substrate 1.
In step S805, the controller 90 can determine whether the shape information (height distribution) obtained in step S804 is allowable. This determination can be done by, for example, judging whether an index (for example, the maximum height difference of the measurement target region of the substrate 1) obtained from the shape information obtained in step S804 falls within a preset allowable range. If the shape information (height distribution) obtained in step S804 is allowable, the controller 90 can end the measurement processing shown in
Step S801 is an example of the first step of performing first measurement of measuring the height of at least one measurement point of the measurement target region by the height measurement device 81 and air pressure measurement of measuring, by the pressure measurement device 80, the air pressure that influences the result of the first measurement. In the first step, the air pressure measurement can be performed in synchronism with the first measurement. Step S803 is an example of the second step of performing second measurement of measuring the heights of a plurality of measurement points of the measurement target region by the height measurement device 81. Steps S802 and S804 are an example of the third step of obtaining shape information representing the shape of the measurement target region by correcting the result obtained in the second step based on the result obtained in the first step. In the third step, the shape information can be obtained by correcting the result of the second measurement based on the frequency component derived from the variation of the air pressure included in the result of the first measurement.
In the first and second embodiments, the height distribution (shape) of the measurement target region or the surface of the substrate 1 is measured. Instead, the height distribution (shape) of the substrate holding surface of the substrate holder 11 may be measured. In this case, the measurement target region can include at least a part of the substrate holding surface of the substrate holder 11.
In the first and second embodiments, the height of the movable body 21 varies due to the variation of the air pressure, and this influences the results of the first measurement and the second measurement by the height measurement device 81. In the third and fourth embodiments to be described below, the height distribution (shape) of the measurement target region of the mold 41 is measured by a height measurement device 82 supported by the movable body 21. The height of the movable body 21 varies due to the variation of the air pressure, and this influences the results of first measurement and second measurement by a height measurement device 82.
The third embodiment will be described below with reference to
ΔZm1_M0=Km0×ΔPm1_M0 (10)
holds.
The height of the movable body 21 that almost maintains the horizontal posture varies in accordance with equation (10). Hence, letting Km be the correction coefficient used to correct the height measured by the height measurement device 82, the correction coefficient Km used when the height is measured only at the origin M0 can be given by
Km=Km0 (11)
ΔZm1_M1=Km1×ΔPm1_M1 (12)
ΔZm1_M2=Km2×ΔPm1_M2 (13)
ΔZm1_M3=Km3×ΔPm1_M3 (14)
ΔZm1_M4=Km4×ΔPm1_M4 (15)
Since the height of the movable body 21 changes following the variation of the air pressure in accordance with equations (10), (12), (13), (14), and (15), the correction coefficient Km used when the heights of the five measurement points M0 to M4 are measured can be given by
Km=(KM4−KM2)÷(KM4_x−KM2_x)×X+(KM3−KM1)÷(KM3_y−KM1_y)×Y+KM0 (16)
where KM2_x and KM4_x represent the x-coordinates of the measurement points M2 and M4, and KM1_y and KM3_y represent the y-coordinates of the measurement points M1 and M3. In addition, X and Y represent an arbitrary point on the mold 41 on the XY coordinate system.
In this example, the measurement points are set to the origin M0, the points M2 and M4 on the X-axis, and the points M1 and M3 on the Y-axis. However, the number and positions of measurement points are not limited to this example, and arbitrary points on the mold 41 can be set to measurement points. In addition, the first measurement by the height measurement device 82 and the air pressure measurement by the pressure measurement device 80 are preferably performed at least for one period of the variation of the air pressure.
Zmt1(x,y)=Zm2(x,y)−Km×(Pm2(x,y)−Pm2(0,0)) (17)
where Pm2(0, 0) is a pressure measured by the pressure measurement device 80 when measuring the height of the origin (0, 0) of the XY coordinate system on the mold 41. However, an arbitrary point on the mold 41 can be set to the reference point. In addition, the arrangement of the plurality of measurement points in the second measurement by the height measurement device 82 may be determined such that the measurement points are arranged on each of a plurality of lines parallel to the X direction. Alternatively, the arrangement of the plurality of measurement points in the second measurement by the height measurement device 82 may be determined such that the measurement points are arranged on each of a plurality of lines in an oblique direction with respect to the X or Y direction. Alternatively, the arrangement of the plurality of measurement points in the second measurement by the height measurement device 82 may be determined such that the plurality of measurement points are arranged on a spiral line.
In step S1201, the controller 90 controls execution of first measurement of measuring the height of at least one measurement point of the measurement target region of the mold 41 by the height measurement device 82 and air pressure measurement of measuring the air pressure by the pressure measurement device 80 in synchronism with the first measurement. The first measurement may be performed for a plurality of measurement points of the measurement target region of the mold 41. As for the number of times of measurement (sampling) at each measurement point, the measurement is preferably performed at least for one period of the variation of the air pressure measured by the pressure measurement device 80.
In step S1202, the controller 90 or the calculator 91 calculates or determines the correction coefficient Km based on the results of the first measurement and the air pressure measurement in step S1201. In step S1203, the controller 90 controls execution of second measurement of measuring the heights of a plurality of measurement points of the measurement target region of the mold 41 by the height measurement device 82 and air pressure measurement of measuring the air pressure by the pressure measurement device 80 in synchronism with the second measurement. In step S1204, the controller 90 or the calculator 91 corrects the result of the second measurement by the height measurement device 82 based on the correction coefficient Km calculated or determined in step S1202, thereby obtaining shape information representing the shape of the measurement target region of the mold 41. In other words, in step S1204, the controller 90 or the calculator 91 corrects the result of the second measurement by the height measurement device 82 based on the result of the first measurement by the height measurement device 82 and the result of the air pressure measurement by the pressure measurement device 80. Accordingly, the controller 90 or the calculator 91 obtains shape information representing the shape of the measurement target region of the mold 41.
In step S1205, the controller 90 can determine whether the shape information (height distribution) obtained in step S1204 is allowable. This determination can be done by, for example, judging whether an index (for example, the maximum height difference of the measurement target region of the mold 41) obtained from the shape information obtained in step S1204 falls within a preset allowable range. If the shape information (height distribution) obtained in step S1204 is allowable, the controller 90 can end the measurement processing shown in
The fourth embodiment will be described below with reference to
The frequency Fpm1_1 can be regarded as the main frequency of the variation of the air pressure. The frequency Fzm1 can have various peaks depending on the arrangement of an imprint apparatus 101 in addition to the influence of the variation of the air pressure in the plant facility. For this reason, even if the frequency representing the peak is obtained by frequency analysis of the result of the first measurement by the height measurement device 82, it is impossible to discriminate whether the frequency is the frequency of the variation of the height caused by the variation of the air pressure. On the other hand, even if the frequency representing the peak is obtained by frequency analysis of the result of the air pressure measurement by the pressure measurement device 80, it is also impossible to discriminate whether the pressure variation at the frequency has an influence on the measurement result of the height of the measurement point of the mold 41.
Hence, the calculator 91 can compare the main frequency Fpm1_1 of the variation of the air pressure measured by the pressure measurement device 80 with the frequencies of the plurality of peaks in the variation of the height measured by the height measurement device 82. As the result of the comparison, if one of the frequencies of the plurality of peaks in the variation of the height matches the main frequency Fpm1_1 of the variation of the air pressure, the frequency that matches the main frequency Fpm1_1 can be regarded as the frequency of the variation of the measurement result of the height caused by the variation of the air pressure.
Here, let Fm be the frequency that matches the main frequency Fpm1_1 of the variation of the air pressure in the frequencies Fzm1_1 of the plurality of peaks in the variation of the height measured by the height measurement device 82. Fm is given by
Fm=Fpm1_1 (18)
If none of the frequencies Fzm1_1 of the plurality of peaks in the variation of the height measured by the height measurement device 82 matches the main frequency Fpm1_1, it can be considered that the influence of the variation of the air pressure does not exist in the height measurement of the mold 41. An example in which the origin M0 on the mold 41 is set to the measurement point in the first measurement has been described here. However, the measurement point in the first measurement can arbitrarily be determined. In the fourth embodiment as well, the first measurement by the height measurement device 82 and the measurement of the air pressure by the pressure measurement device 80 are preferably performed at least for one period of the variation of the air pressure. If the period is shorter than one period, a high frequency component that cannot exist originally is added as the measurement result, and therefore, there may be a possibility that a desired result cannot be obtained.
The calculator 91 can perform frequency analysis of the measurement result of the height obtained by the second measurement by the height measurement device 82 and determine whether the component of the frequency Fm is included. If the component of the frequency Fm is included in the measurement result of the height obtained by the second measurement by the height measurement device 82, the calculator 91 can remove the component of the frequency Fm from a result Zm2(x, y) of the measurement in the second measurement by the height measurement device 82. This makes it possible to obtain a height distribution Zmt1 (x, y) in the measurement target region of the mold 41, from which the variation of the air pressure is removed.
In step S1501, the controller 90 controls execution of first measurement of measuring the height of at least one measurement point of the measurement target region of the mold 41 by the height measurement device 82 and air pressure measurement of measuring the air pressure by the pressure measurement device 80 in synchronism with the first measurement. The first measurement may be performed for a plurality of measurement points of the measurement target region of the mold 41. As for the number of times of measurement (sampling) at each measurement point, the measurement is preferably performed at least for one period of the variation of the air pressure measured by the pressure measurement device 80.
In step S1502, the controller 90 or the calculator 91 calculates or determines the frequency Fm of the variation of the air pressure by frequency analysis based on the results of the first measurement and the air pressure measurement in step S1501. In step S1503, the controller 90 controls execution of second measurement of measuring the heights of a plurality of measurement points of the measurement target region of the mold 41 by the height measurement device 82. In step S1504, the controller 90 or the calculator 91 corrects the result of the second measurement by the height measurement device 82 based on the component of the frequency Fm calculated or determined in step S1502, thereby obtaining shape information representing the shape of the measurement target region of the mold 41. In other words, in step S1504, the controller 90 or the calculator 91 corrects the result of the second measurement by the height measurement device 82 based on the result of the first measurement by the height measurement device 82 and the result of the air pressure measurement by the pressure measurement device 80. Accordingly, the controller 90 or the calculator 91 obtains shape information representing the shape of the measurement target region of the mold 41.
In step S1505, the controller 90 can determine whether the shape information (height distribution) obtained in step S1504 is allowable. This determination can be done by, for example, judging whether an index (for example, the maximum height difference of the measurement target region of the mold 41) obtained from the shape information obtained in step S1504 falls within a preset allowable range. If the shape information (height distribution) obtained in step S1504 is allowable, the controller 90 can end the measurement processing shown in
Step S1501 is an example of the first step of performing first measurement of measuring the height of at least one measurement point of the measurement target region by the height measurement device 82 and air pressure measurement of measuring, by the pressure measurement device 80, the air pressure that influences the result of the first measurement. In the first step, the air pressure measurement can be performed in synchronism with the first measurement. Step S1503 is an example of the second step of performing second measurement of measuring the heights of a plurality of measurement points of the measurement target region by the height measurement device 82. Steps S1502 and S1504 are an example of the third step of obtaining shape information representing the shape of the measurement target region by correcting the result obtained in the second step based on the result obtained in the first step. In the third step, the shape information can be obtained by correcting the result of the second measurement based on the frequency component derived from the variation of the air pressure included in the result of the first measurement.
In the third and fourth embodiments, the height distribution (shape) of the measurement target region or the surface of the mold 41 is measured. Instead, the height distribution (shape) of the mold holding surface of the mold holder 51 may be measured. In this case, the measurement target region can include at least a part of the mold holding surface of the mold holder 51.
An article manufacturing method according to an embodiment will be described below. An article manufacturing method of manufacturing a device (for example, a semiconductor integrated circuit element or a liquid crystal display element) as an article includes a forming step of forming a pattern on a substrate (a wafer, a glass plate, or a film-shaped substrate) using the above-described imprint apparatus. The manufacturing method can also include a processing step of processing (for example, etching) the substrate with the pattern being formed. Note that when manufacturing another article such as a pattered medium (recording medium) or an optical element, the manufacturing method can include another process of processing the substrate with the pattern being formed in place of etching. The article manufacturing method according to this embodiment is superior to a conventional method in at least one of the quality, productivity, and production cost of the article.
Embodiment(s) of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2020-089073, filed May 21, 2020, which is hereby incorporated by reference herein in its entirety.
Number | Date | Country | Kind |
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2020-089073 | May 2020 | JP | national |