JP2018041811A - Imprint apparatus and article manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique advantageous to achieve both positioning accuracy between a mold and a substrate and the throughput of an apparatus.SOLUTION: There is provided an imprint apparatus forming a pattern of an imprint material on a processed region of a substrate using a mold. The imprint apparatus includes: a substrate holding part movable while holding the substrate; a hydrostatic bearing supporting the substrate holding part in a non-contact manner with respect to a guide face by ejecting a gas toward the guide face; and an adjustment part adjusting the pressure of a gas ejected by the hydrostatic bearing. The adjustment part lowers the pressure of the gas until the positioning between the mold and the processed region is completed after the processed region faces the mold.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an imprint apparatus and an article manufacturing method.

  As one of lithography techniques for manufacturing articles such as semiconductor devices, an imprint apparatus for forming a pattern by bringing a mold into contact with an imprint material on a substrate is being put into practical use.

  Imprint apparatuses are required to improve the positioning accuracy between the mold and the substrate. Patent Document 1 discloses a technique for adjusting a supply pressure of an air pad according to a moving state (acceleration) of a stage in an exposure apparatus that exposes a substrate and transfers a pattern onto the substrate.

JP 2006-065589 A

  However, there is a response delay in the pneumatic system. In the exposure apparatus as disclosed in Patent Document 1, since the acceleration / deceleration operation time is very short, there is a possibility that the switching of the supply pressure is not in time due to such a response delay. Therefore, it is necessary to extend the acceleration / deceleration operation time, and there is a problem that it is difficult to improve the throughput. Further, in the technique of Patent Document 1, as a result of drastically reducing the supply pressure of the air pad in order to improve the minute vibration of the air pad, there is a problem that the rigidity of the air pad is lowered, the servo band is lowered, and the positioning deviation is increased. is there.

  An object of the present invention is, for example, to provide a technique advantageous in achieving both the positioning accuracy of a mold and a substrate and the throughput of the apparatus.

  According to one aspect of the present invention, there is provided an imprint apparatus for forming a pattern on a substrate by bringing a mold into contact with an imprint material on the substrate, the substrate holding unit holding the substrate, and a guide surface A platen, a movable part that supports the substrate holding part and can move the substrate holding part by moving along the guide surface, and a gap between the movable part and the guide surface. A static pressure bearing that ejects pressurized gas and supports the movable part in a non-contact manner with respect to the guide surface by the pressurized gas; an adjustment unit that adjusts the pressure of the pressurized gas; and a control unit. The control unit is configured to align the shot region and the mold after contacting the mold with the imprint material supplied on the shot region of the substrate, and the control unit Before the contact is made to the shot area The adjustment unit is controlled to reduce the pressure of the pressurized gas at a timing until the alignment is completed after the substrate holding unit is moved so as to be positioned under the mold. An imprint apparatus is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the technique advantageous for coexistence with the positioning precision of a type | mold and a board | substrate and the throughput of an apparatus is provided.

The figure which shows the structure of the imprint apparatus in embodiment. The figure which shows the structure of the control system of the substrate stage apparatus in embodiment. The top view which shows the structure of the substrate stage apparatus in embodiment. The bottom view which shows the structure of the substrate stage apparatus in embodiment. Sectional drawing which shows the structure of the substrate stage apparatus in embodiment. The figure which shows the modification of the pressure control system of the static pressure bearing of the substrate stage apparatus in embodiment. The flowchart explaining the example of the pressure control of the air pad in an imprint process. The flowchart explaining the modification of the pressure control of the air pad in an imprint process. The flowchart explaining the modification of the pressure control of the air pad in an imprint process. The flowchart explaining the modification of the pressure control of the air pad in an imprint process. The flowchart explaining the modification of the pressure control of the air pad in an imprint process. The flowchart explaining the modification of the pressure control of the air pad in an imprint process. The flowchart explaining the modification of the pressure control of the air pad in an imprint process.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the following embodiment, The following embodiment shows only the specific example of implementation of this invention. Moreover, not all combinations of features described in the following embodiments are indispensable for solving the problems of the present invention.

  Hereinafter, the imprint apparatus according to the present embodiment will be described. The imprint apparatus is an apparatus that forms a pattern of an imprint material on a processing area of a substrate. More specifically, the imprint apparatus is a cured product in which the concave / convex pattern of the mold is transferred by bringing the imprint material arranged on the substrate into contact with the mold and applying energy for curing to the imprint material. Is an apparatus for forming the pattern. The imprint material may be a curable composition (which may be referred to as an uncured resin) that is cured when energy for curing is applied. The energy for curing can be electromagnetic waves or heat. The electromagnetic wave can be, for example, light (infrared rays, visible rays, ultraviolet rays, etc.) having a wavelength selected from a range of 10 nm to 1 mm.

  A curable composition is a composition which hardens | cures when energy for hardening, such as electromagnetic waves or a heat | fever, is given. Among these, the photocurable composition cured by light contains at least a polymerizable compound and a photopolymerization initiator, and may further contain a non-polymerizable compound or a solvent as necessary. The non-polymerizable compound may be at least one selected from the group consisting of a sensitizer, a hydrogen donor, an internal release agent, a surfactant, an antioxidant, and a polymer component.

  The imprint material can be applied in the form of a film on the substrate by a spin coater or a slit coater. Alternatively, the imprint material can be supplied onto the substrate in a droplet state by the liquid ejecting head or in an island state or a film state formed by connecting a plurality of droplets. The viscosity of the imprint material (viscosity at 25 ° C.) can be, for example, 1 mPa · s or more and 100 mPa · s or less.

  The substrate can be a member made of glass, ceramics, metal, semiconductor, resin, or the like. If necessary, a layer made of a material different from the member may be formed on the surface of the member. The substrate is, for example, a silicon wafer, a compound semiconductor wafer, or a quartz glass plate.

  FIG. 1 shows a configuration example of the imprint apparatus IMP in the present embodiment. The main body structure 1 of the imprint apparatus IMP is installed on the floor via a plurality (typically 3 or 4) of vibration isolation units 2. The substrate 3 is placed on the substrate chuck 28 b in the substrate stage device 14. The substrate 3 is placed on the substrate chuck 28b so that the surface thereof is parallel to the horizontal plane (XY plane). The substrate stage device 14 has a stroke sufficient to move the substrate 3 to a substrate replacement position for loading and unloading the substrate 3 and a dropping position for placing an imprint material on the substrate 3 X. Can have an axis and a Y axis.

  The substrate holding unit 28 that holds the substrate may include a top plate 28a and the above-described substrate chuck 28b mounted on the top plate 28a. The substrate stage device 14 includes a surface plate 13, an X slider 12 (first slider) that is disposed on the surface plate 13 and moves in the X direction, and a Y slider 4 that is movable in the Y direction while being guided by the X slider 12. (Second slider). The substrate holding unit 28 is mounted on the Y slider 4 and can move on the surface plate 13 by the X slider 12 and the Y slider 4. The positions of the top board 28a (XYθ stage) and the X slider 12 are determined by a measuring instrument MD such as a linear encoder including a detection head 15 that moves together with the X slider 12 and a scale 16 provided on the surface plate 13, for example. It is measured. The position of the Y slider 4 is similarly measured by the measuring instrument MD, but since the configuration for measuring the position of the Y slider 4 does not appear in FIG. 1, the configuration of the measuring instrument MD will be described later with reference to FIG. To do. Instead of the linear encoder described above, a laser interferometer that can be configured by a laser head and a mirror provided on a movable body (for example, Y slider 4) of the substrate stage device 14 may be provided.

  The imprint material can be supplied (arranged) on the shot region of the substrate 3 by the supply unit 7. The imprint material may be supplied onto the shot area of the substrate 3 by an external device of the imprint apparatus IMP. The imprint apparatus IMP according to the present embodiment forms a pattern on one shot area as a process target area per imprint process. The process area may include a plurality of shot areas. The imprint process may include an operation of bringing the mold 8 as a mold into contact with the imprint material on the substrate and an operation of separating the mold 8 from the cured imprint material.

  The imprint apparatus IMP may include an imprint head 9 that drives the mold 8. The imprint head 9 that is a mold holding unit holds the mold 8 and drives the mold 8 about a plurality of axes (for example, six axes of X axis, Y axis, Z axis, θX axis, θY axis, and θZ axis). Can be configured to. In particular, the imprint head 9 can drive the mold 8 with respect to the Z axis (that is, descend and rise with respect to the substrate 3). Thereby, the contact of the mold 8 with the imprint material on the substrate 3 and the separation of the mold 8 from the cured imprint material on the substrate 3 can be controlled.

  The imprint apparatus IMP may include a load cell 81 that measures a load applied between the mold 8 and the imprint material on the substrate 3 in the vicinity of the portion of the imprint head 9 that holds the mold 8. Further, the imprint apparatus IMP may include a sensor 6 that detects the displacement of the mold 8 in the XY directions in the vicinity of the imprint head 9. Further, the imprint apparatus IMP may include an alignment detector 10 that detects a relative position between the mold 8 and the shot area of the substrate 3 in the X direction and the Y direction. The substrate 3 on which the layer is formed by the lithographic apparatus has an alignment mark. The alignment detector 10 can be configured to detect the relative position between the shot region of the substrate 3 and the mold 8 using the alignment mark of the substrate 3 and the alignment mark of the mold 8.

  The imprint apparatus IMP may include a curing unit 11 that supplies energy for curing the imprint material to the imprint material. The curing unit 11 brings the mold 8 into contact with the imprint material on the substrate 3 and supplies the imprint material with energy for curing the imprint material after the concave portion of the uneven pattern of the mold 8 is filled with the imprint material. To do.

  FIG. 2 is a diagram illustrating a configuration of the control system CS of the substrate stage apparatus 14. The operation of the control system CS will be described together with the operation of the imprint apparatus IMP. Control of the position of the top plate 28a (which can also be considered as the position of the Y slider 4 or the substrate 3) can be performed by the stage control unit 20. The stage control unit 20 controls the substrate stage device 14 based on the deviation between the command value of the stage position (the position of the top plate 28a) sent from the main control unit 19 and the measurement result of the stage position by the measuring instrument MD. A feedback control system can be configured.

  First, the main control unit 19 supplies a stage position command value indicating the substrate replacement position to the stage control unit 20, and the stage control unit 20 uses the command value and the measurement result of the stage position supplied from the measuring instrument MD. Based on this, the top plate 28a is moved. At the substrate exchange position, the substrate 3 is mounted on the substrate chuck 28b on the top plate 28a by a transport mechanism (not shown). At this time, due to the positioning accuracy of the transport mechanism, the substrate 3 can be arranged on the substrate chuck 28b with an error with respect to the X axis, Y axis, and θZ axis. This error can be measured by detecting the relative position of a reference mark (not shown) provided on the top plate 28a and the alignment mark of the substrate 3 by the alignment detector 10.

  The error measured by the alignment detector 10 is sent to the stage position correction unit 17. The stage position correction unit 17 provides this error to the stage control unit 20 as an offset value. The stage controller 20 corrects the stage position command value from the main controller 19 with the offset value, so that the aforementioned error can be canceled. Instead of such an operation, the position of the mold 8 may be adjusted by the imprint head 9 based on the error measured by the alignment detector 10. Further, based on the error measured by the alignment detector 10, the error may be canceled by both the control of the top plate 28 a by the stage control unit 20 and the control of the mold 8 by the imprint head 9.

  Next, the main control unit 19 controls the substrate stage device 14 via the stage control unit 20 so that the shot area of the substrate 3 is located below the supply unit 7, and the imprint material is supplied onto the shot area. The supply unit 7 is controlled as described above. Next, the main control unit 19 controls the substrate stage device 14 through the stage control unit 20 so that the shot region faces the mold 8, and the imprint material on the shot region is brought into contact with the imprint material. The print head 9 is controlled. Here, in one example, by setting the gap between the upper surface of the substrate 3 and the pattern surface of the mold 8 to 1 μm or less, the imprint material on the substrate 3 and the mold 8 come into contact with each other and The recess is filled with the imprint material.

  Here, immediately after the imprint material on the substrate 3 comes into contact with the pattern surface of the mold 8, the relative positional deviation in the XY plane between the mold 8 and the shot region of the substrate 3 is large. This positional deviation is measured by the alignment detector 10, and the substrate stage apparatus 14 is controlled via the stage position correction unit 17 and the stage control unit 20 based on the measurement result. By repeating such an operation, the relative displacement in the XY plane between the mold 8 and the shot area of the substrate 3 can be within an allowable range. Instead of such an operation, the imprint head 9 may adjust the position of the mold 8 so that the relative displacement in the XY plane is reduced based on the error measured by the alignment detector 10. Good. Further, based on the error measured by the alignment detector 10, the relative displacement in the XY plane is controlled by both the control of the top plate 28 a by the stage controller 20 and the control of the mold 8 by the imprint head 9. May be.

  After the relative positional deviation between the mold 8 and the shot area of the substrate 3 falls within the allowable range, the main control unit 19 moves the curing unit 11 so that the energy for curing is supplied to the imprint material. Control. Thereby, the imprint material is cured. Thereafter, the main control unit 19 controls the imprint head 9 so that the mold 8 is separated from the cured imprint material.

  3 to 5 show specific configuration examples of the substrate stage apparatus 14. 3 is a plan view of the substrate stage device 14, FIG. 4 is a bottom view of the movable portion MP in FIG. 3, and FIG. 5 is a cross section of the movable portion MP along the line AA in FIG. The substrate stage device 14 is configured as a positioning device that positions the substrate 3. The substrate stage device 14 is configured to move the movable portion MP on the first guide surface BPGS constituted by the upper surface of the surface plate 13. The movable part MP supports the substrate holding part 28 and makes it possible to move the substrate holding part 28 by moving along the first guide surface BPGS. The first guide surface BPGS is a surface parallel to the X direction and the Y direction orthogonal to each other (a surface parallel to the XY plane). The platen 13 can be, for example, a granite platen that has been sealed, or a platen that is formed by subjecting a silicon steel plate to ceramic spraying or plating.

  The substrate stage device 14 includes a guide G that restrains the position of the movable part MP in the Y direction. The guide G may include a second guide surface 26 formed on the surface plate 13 and perpendicular to the first guide surface BPGS and parallel to the X direction. The guide G may be configured separately from the surface plate 13 and fixed to the surface plate 13.

  The movable part MP includes an X movable body 22, an X slider 12, and a Y slider 4. The X movable body 22 is movable in the X direction (first direction) while being guided by the guide G (second guide surface 26). The substrate stage device 14 has a plurality of types of air pads, described below, for injecting pressurized gas between the X slider 12 and the Y slider 4 and the first guide surface BPGS and the second guide surface 26 in the movable part MP. . These air pads function as a hydrostatic bearing that supports the substrate holding portion 28 in a non-contact manner with respect to the guide surface by ejecting gas toward the guide surface. The X-slider 12 is not in contact with the first guide surface BPGS by the X bottom air pads 30a, 30b, 30c, 30d constituting the first static pressure bearing that ejects gas toward the first guide surface BPGS of the surface plate 13. Supported by contact. The first end (the end on the + Y direction side) of the X slider 12 is connected to the X movable body 22 via the rotary bearing 23. The X movable body 22 can be guided by the guide G (second guide surface 26) by X lateral air pads 31a, 31b, 31c constituting a second static pressure bearing that ejects gas toward the second guide surface 26. That is, the X movable body 22 can be guided by the guide G (second guide surface 26) without contact with the guide G (second guide surface 26). Therefore, the X slider 12 can move along the second guide surface 26 on the first guide surface BPGS of the surface plate 13. The Y slider 4 is guided in the X slider 12 in the Y direction (second direction orthogonal to the first direction) within a predetermined range between the first end and the second end (end on the −Y direction side). It is movable. The Y slider 4 will be described later with reference to FIG.

  The substrate stage device 14 includes a drive unit DP that drives the movable unit MP. The drive unit DP includes a first drive unit DP1 that drives the first end of the X slider 12 in the X direction, and a second drive unit DP1 that drives the second end of the X slider 12 in the X direction. The first drive unit DP1 can be configured with, for example, a linear motor. More specifically, the first drive unit DP1 may be configured with a linear motor including a first mover 24R and a first stator 25R. The first mover 24 </ b> R can be connected to the first end of the X slider 12, and the first stator 25 </ b> R can be connected to the side surface of the surface plate 13. The second guide surface 26 of the guide G can be disposed between the first stator 25 </ b> R and the X movable body 22. In other words, the first stator 25L is disposed outside the second guide surface 26 when viewed from the movable part MP. Such a configuration is advantageous for reducing the influence of heat on the substrate 3 by moving the first stator 25R, which can be a heat source, away from the movable portion MP, particularly the Y slider 4 (top plate 28a) holding the substrate 3. It is.

  The second drive unit DP2 can be configured with, for example, a linear motor. More specifically, the second drive unit DP2 may be configured with a linear motor including a second mover 24L and a second stator 25L. The second mover 24 </ b> L can be connected to the second end of the X slider 12, and the second stator 25 </ b> L can be connected to the side surface of the surface plate 13. On the second end side of the X slider 12, there is no guide for restraining the position of the second end in the Y direction. Therefore, the distance between the second stator 25L and the second end of the X slider 12 changes according to the rotation of the X slider 12 about the rotation axis of the rotary bearing 23. Such a configuration is simpler than a configuration in which the θZ stage is disposed on the Y slider 4 and is advantageous for increasing the stroke related to the θZ axis.

  The measuring instrument MD that measures the stage position includes a first measuring instrument MD1, a second measuring instrument MD2, and a third measuring instrument MD3. The position of the first end of the X slider 12 in the X direction can be measured by the first measuring instrument MD1. The first measuring instrument MD1 can be, for example, a first linear encoder that includes a detection head 15R that moves together with the first end of the X slider 12 and a scale 16R installed on the surface plate 13. The position of the second end of the X slider 12 in the X direction can be measured by the second measuring instrument MD2. The second measuring instrument MD2 can be, for example, a second linear encoder including a detection head 15L that moves together with the second end of the X slider 12 and a scale 16L installed on the surface plate 13. Further, the position of the Y slider 4 in the Y direction can be measured by the third measuring instrument MD3. The third measuring instrument MD3 can be, for example, a third linear encoder including a detection head 41 disposed on the Y slider 4 and a scale 40 disposed on the upper surface of the X slider 12.

  The X slider 12 can rotate on the first guide surface BPGS of the surface plate 13 around the rotation axis of the rotary bearing 23. The rotation amount of the X slider 12 can be calculated based on the measurement results obtained by the first measuring instrument MD1 and the second measuring instrument MD2. The Y slider 4 can move in the Y direction while being guided by a guide surface provided on the X slider 12. The Y slider 4 can be driven in the Y direction by an actuator of a linear motor. The substrate 3 held by the Y slider 4 and the substrate holder 28 can be positioned with respect to the X axis, the Y axis, and the θZ axis.

  As illustrated in FIG. 5, the Y slider 4 is disposed so as to partially surround the X slider 12. In other words, the X slider 12 is disposed so as to penetrate the Y slider 4. On the inner surface of the side wall of the Y slider 4, Y lateral air pads 36a and 36c constituting the third hydrostatic bearing are arranged to face each other. As a result, the Y slider 4 is guided in a non-contact manner along the third guide surface 27 constituted by the side surface of the X slider 12 which is orthogonal to the first guide surface BPGS and the second guide surface 26. On the bottom of the Y slider 4, Y bottom air pads 29 a, 29 b, 29 c, 29 d constituting the fourth hydrostatic bearing are arranged, so that the Y slider 4 is not contacted by the first guide surface BPGS of the surface plate 13. Supported and guided.

  Accordingly, the substrate 3 is supported by the surface plate 13 via the substrate holding portion 28, the Y slider 4, and the Y bottom air pads 29a, 29b, 29c, 29d. Preload magnets 32 a, 32 b, 32 c, and 32 d are disposed on the lower surface of the Y slider 4. The preload magnets 32a, 32b, 32c, 32d are arranged so as to sandwich the Y bottom air pads 29a, 29b, 29c, 29d. The attractive force in the Z direction by the preload magnets 32 a, 32 b, 32 c, and 32 d is determined so that a predetermined gap is secured between the first guide surface BPGS and the bottom surface of the Y slider 4. The first guide surface BPGS of the surface plate 13 and the second guide surface 26 of the guide G can be made of, for example, silicon steel when the preload is generated by the preload magnet as in this embodiment. As the preload mechanism, a vacuum mechanism that applies an attractive force in the Z-axis direction by exhaust may be employed instead of the preload magnet. The X slider 12 is provided with a linear motor coil 39 that generates a thrust force for driving the Y slider 4 in the Y direction, and a movable magnet 42 is disposed inside the Y slider 4.

  As a preload mechanism for the X lateral air pads 31a, 31b, 31c, preload magnets 35a, 35b, 35c, 35d may be employed. The pressure generated by the X lateral air pads 31a, 31b, 31c is often high, for example, 0.3 to 0.4 MPa. Therefore, when the preload magnets 35a, 35b, 35c, and 35d are arranged inside the X lateral air pads 31a, 31b, and 31c, the X movable body 22 is warped, and at the end, the second guide surface 26 and the X movable body 22 The gap may widen and the pad surface may have a non-uniform pressure distribution. As a result, the pressure becomes unstable, causing vibration, and the positioning accuracy can be lowered. Therefore, it is preferable to dispose the preload magnets 35a, 35b, 35c, and 35d outside the X lateral air pads 31a, 31b, and 31c of the X movable body 22. Thereby, since the gap between the second guide surface 26 and the X movable body 22 can be made uniform, vibration can be reduced and positioning accuracy can be improved.

  Next, control of the supply pressure of the hydrostatic bearing (air pad) will be described. As described above, the Y-side air pads 36a and 36c are arranged to face each other with the X slider 12 interposed therebetween (both sides-constrained air pads). When the pressurized gas supplied from the Y lateral air pads 36a and 36c is set to a low pressure, the minute vibration of the Y slider 4 in the X direction is reduced, but the rigidity is lowered. However, the minute vibrations of the Y-side air pads 36a and 36c can be reduced by contacting the mold 8 and the substrate 3 on the substrate holding unit 28 via the imprint material during imprinting. For this reason, since the amount of decrease in the supply pressure can be reduced as compared with an exposure apparatus in which no imprint material is present, the influence of a decrease in rigidity can be reduced.

  In FIG. 5, the Y lateral air pads 36 a and 36 c are connected to the adjusting unit 51 via the pipe 33. The adjustment unit 51 can be disposed on any of the Y slider 4, the X slider 12, and the surface plate 13. When the adjustment unit 51 is disposed on the Y slider 4, the pipe 33 can be fixed to the Y slider 4. When the adjustment unit 51 is disposed on the X slider 12 or the surface plate 13, the pipe 33 includes a movable pipe in the Y direction or a movable pipe in the X direction. The adjustment unit 51 includes, for example, an electric proportional regulator, and can change the pressure of the gas supplied from the compressor 53, which is a pressurized gas generation source, to a value designated from the main control unit 19 via the pressure control unit 52. it can. The pipe 33 is provided with a pressure sensor 55 that detects the pressure of the pressurized gas in the pipe 33. The main control unit 19 can measure the pressure of the air pad based on the output value of the pressure sensor 55 via the pressure control unit 52. According to the configuration of FIG. 5, it is possible to arbitrarily change the pressure of the pressurized gas supplied from the Y lateral air pads 36 a and 36 c by the adjustment unit 51 and the pressure control unit 52.

  FIG. 6 shows a modification of the pressure control system shown in FIG. In FIG. 6, the Y lateral air pads 36 a and 36 c are connected to the adjustment unit 61 via the pipe 33. A first regulator 62 set to the first pressure and a second regulator 63 set to a second pressure higher than the first pressure are connected to the adjustment unit 61. The adjustment unit 61, the first regulator 62, and the second regulator 63 can be disposed on any of the Y slider 4, the X slider 12, and the surface plate 13. The adjusting unit 61 includes, for example, an electromagnetic valve, and the pressure control unit 52 causes either the first regulator 62 or the second regulator 63 to communicate with the pipe 33 so that the low-pressure or high-pressure pressurized gas is supplied to the Y-side air pads 36a, 36c. Can be supplied to. According to the configuration of FIG. 6, the pressure of the pressurized gas supplied from the Y lateral air pads 36 a and 36 c by the adjusting unit 61 and the pressure control unit 52 can be changed to either high pressure or low pressure.

  In the configuration illustrated in FIG. 5, not only high pressure and low pressure but also pressure can be changed arbitrarily, so that pressure setting for reducing minute vibrations or pressure setting for improving rigidity can be performed in multiple stages. it can. On the other hand, in the configuration illustrated in FIG. 6, it is possible to change the pressure only in two stages of high pressure and low pressure. However, according to this configuration, the pressure of the gas supplied to the Y-side air pads 36a and 36c can be changed only by the flow path switching operation, so that the pressure can be changed at a higher speed.

  The first regulator 62 and the second regulator 63 may be manual regulators or electric proportional regulators. When using an electric proportional regulator, the electric proportional regulator that is not supplied to the Y-side air pads 36a and 36c may be changed to a predetermined pressure in advance, and then the adjustment unit 61 may perform switching. Accordingly, the pressurized gas can be supplied at the predetermined pressure simultaneously with the switching operation of the adjusting unit 61, and the pressure can be changed at high speed.

  X side air pads 31a, 31b, 31c, X bottom air pads 30a, 30b, 30c, 30d, and Y bottom air pads 29a, 29b, 29c, 29d) guide the load capacity of the air pad by using a preload magnet in balance with the attractive force. (One side restraint type air pad). Therefore, in these three types of air pads, since the flying height is reduced by switching the supply pressure to a low pressure, the flow rate of the air pads is reduced, and minute vibrations of the air pads can be reduced. And since the flying height decreases as the flow rate decreases, the rigidity of the air pad does not change much compared to before the pressure is switched to a low pressure. Therefore, in the one-side constrained air pad, by reducing the pressure, micro vibrations can be reduced without reducing the rigidity.

  A configuration may be adopted in which the pressure is adjusted only for the necessary air pads in accordance with the stage attitude error and the position error. In the case of a one-side restraint type air pad, the offset of the flying position may be measured in advance. Alternatively, the measuring device MD is used as an offset measuring unit, the offset of the flying position is measured, and when the substrate 3 and the mold 8 are aligned using the alignment detector 10, the stage position command value is corrected with the offset. May be.

  Next, an operation flow of imprint processing in the imprint apparatus according to the embodiment will be described with reference to a flowchart of FIG.

  In step 1, the main control unit 19 moves the substrate holding unit 28 to the substrate replacement position via the stage control unit 20. At the substrate exchange position, the substrate 3 is mounted on the substrate chuck 28b by a transport mechanism (not shown). At this time, due to the positioning accuracy of the transport mechanism, the substrate 3 can be arranged on the substrate chuck 28b with an error (mounting error) with respect to the X axis, the Y axis, and the θZ axis.

  This mounting error is detected by the alignment detector 10 in step 2 as described above with reference to FIG. 2 by using the alignment detector 10 to detect the relative position between a reference mark (not shown) provided on the top plate 28a and the alignment mark on the substrate 3. Measured accordingly. In the following positioning process, the stage control unit 20 can correct the command value of the stage position with the offset value corresponding to the mounting error.

  In step 3, the main control unit 19 moves the substrate 3 from a position below the alignment detector 10 via the stage control unit 20 so that the shot area of the substrate 3 is positioned below the supply unit 7. Position it. At this time, the substrate 3 can be moved at high acceleration and high speed in order to improve throughput. In step 4, the supply unit 7 supplies an imprint material to the shot area of the substrate 3.

  In step 5, the main control unit 19 positions the shot region of the substrate 3 directly below the mold 8 through the stage control unit 20 so that the shot region of the substrate 3 faces the mold 8. At this time, the substrate 3 can be moved at a high acceleration and a high speed in order to improve the throughput. In step 6, the main control unit 19 controls the imprint head 9 to lower the mold 8 toward the substrate 3. Thereby, in step 7, the imprint material on the shot region of the substrate 3 and the mold 8 are brought into contact with each other, and the imprint material is filled in the concave portions of the concavo-convex pattern on the pattern surface.

  In step 8, alignment (alignment) between the mold 8 and the shot region of the substrate 3 is performed. Specifically, the relative displacement between the mold 8 and the shot area of the substrate 3 is measured by the alignment detector 10, and based on the measurement result, the stage position correction unit 17 and the stage control unit 20 are used. Positioning of the mold 8 and the shot area is performed. In step 9, the main control unit 19 controls the curing unit 11 so that energy for curing is supplied to the imprint material. Thereby, the imprint material is cured. Thereafter, in step 10, the main control unit 19 controls the imprint head 9 to raise the mold 8 and separate the mold 8 from the cured imprint material (release).

  Steps 3 to 10 are repeatedly performed on all shot regions of the substrate 3. Then, when it is confirmed in step 11 that the imprint of all the shot areas has been completed, the processing returns to step 1 as the processing for the next substrate.

  Next, air pad pressure control in the above-described imprint process will be described. Hereinafter, as an example of air pad pressure control, an example of controlling the pressure of the Y lateral air pads 36a and 36c (third static pressure bearing) will be mainly described. However, the air pad pressure control described below includes the X bottom air pads 30a to 30d (first static pressure bearing), the X side air pads 31a, 31b and 31c (second static pressure bearing), and the Y bottom air pads 29a to 29d (fourth). It can also be applied to a hydrostatic bearing. Therefore, in the following description, the Y lateral air pads 36a and 36c, the X lateral air pads 31a, 31b and 31c, the Y bottom air pads 29a to 29d, and the X bottom air pads 30a to 30d (first to fourth hydrostatic bearings) are collectively referred to. This is simply called “air pad”. In the following description, for example, the expression “reducing the pressure of the air pad” may also include “reducing the gas pressure in at least one of the first to fourth hydrostatic bearings”.

  As described above, in steps 3 and 5, the substrate 3 can be moved at a high acceleration and a high speed in order to improve the throughput. In order to make this possible, the main control unit 19 controls the adjustment unit 51 to set the pressure of the air pad to a high pressure before performing step 3. Thereafter, the adjusting unit 51 reduces the pressure of the air pad at a timing after the mold 8 and the shot region of the substrate 3 are opposed to each other in the step 5 and until the step 8 in which the alignment is performed in the step 8 is completed. (Switch to low pressure). For example, in step 6, the time for lowering the mold 8 toward the substrate 3 can be secured as the time for switching the pressure of the air pad. Further, in step 7, the time for controlling the position when the mold 8 and the imprint material are brought into contact with each other or controlling the contact force can be secured as the time for switching the pressure of the air pad. Furthermore, in step 8, since it takes time to move the positioning in alignment between the substrate 3 and the mold 8 due to the influence of the viscoelasticity of the imprint material, it can be secured as a time for switching the pressure of the air pad.

  According to the above imprint process, the pressure of the gas from the air pad (for example, the Y lateral air pads 36a and 36c) is lowered after the mold 8 and the shot area are opposed to each other, so that the air pad ejects the gas. Can be suppressed. Thereby, the mark can be detected with high accuracy, and the positioning accuracy between the mold 8 and the shot area is improved. In particular, after the substrate 3 is positioned so that the mold 8 and the shot region face each other and before the mold is lowered, the main control unit 52 instructs the lowering of the pressure of the gas from the air pad. The time is used to realize the pressure drop of the gas from the air pad. In this manner, the response of the pressure change of the air pad can be made in time before the alignment operation between the mold 8 and the substrate 3 is completed.

  As described above, the time secured immediately after the completion of the process 5 and before the completion of the process 8 is longer than the time required for the air pressure response, and thus can be used as a time for switching the pressure of the air pad. Therefore, it is possible to eliminate the influence of switching the pressure of the air pad on the throughput. Further, since the mold 8 and the substrate 3 are in contact with each other through the imprint material, minute vibrations are reduced, thereby improving positioning accuracy. Furthermore, since the amount of decrease in the supply pressure of the air pad can be reduced as compared with an exposure apparatus that does not have an imprint material, the influence of a decrease in rigidity is reduced, resulting in improved positioning accuracy.

  Below, with reference to the flowchart of FIGS. 8-13, the modification of the pressure control of an air pad is demonstrated. First, in the flowchart of FIG. 8, the process A, the process B, the process C, and the process D are added to the flowchart of FIG. 7, and the switching timing of the pressure of the air pad is clearly shown. Description of the same steps as those in FIG. 7 is omitted.

  In step A, before moving the substrate 3 at a high acceleration and a high speed, the main control unit 19 confirms that high-pressure air is supplied to the air pad using the pressure sensor 55 via the pressure control unit 52. If high-pressure air is not supplied, the process can proceed to the next step to prevent the substrate from being moved at high speed while the air pad remains at low pressure. Thereby, damage to the device due to contact between the movable side and the fixed side of the air pad can be prevented.

  After completion of the high-speed movement of the substrate 3 in step 5, in step B, the main control unit 19 controls the adjustment unit 51 via the pressure control unit 52 to switch the pressure of the air pad to a low pressure. As described above, by performing the process B before the operation of the imprint head 9 in the process 6, it is possible to secure the maximum time for switching the pressure of the air pad.

  After the mold 8 comes into contact with the imprint material in Step 7 and before the alignment in Step 8 is performed, in Step C, the main control unit 19 sets the pressure of the air pad as a low pressure via the pressure control unit 52. Confirm that the value is stable. Then, after the imprint material is cured in step 9, in step D, the main control unit 19 controls the adjustment unit 51 via the pressure control unit 52 in order to perform high-speed movement with high acceleration in the next step. Increase the air pad pressure (switch to high pressure).

  According to the air pad pressure control described above, it is possible to achieve both positioning accuracy and apparatus throughput.

  The example of FIG. 9 has an additional step E. In step E, the main control unit 19 confirms that the mold 8 and the imprint material on the substrate 3 are in contact with each other based on the output of the load cell 81. After this confirmation, in step B, the pressure of the air pad is switched to a low pressure. By preventing the process from proceeding to the process B if the contact is not confirmed in the process E, it is possible to prevent the air pad pressure from being switched when the contact is not yet completed.

  Next, the example of FIG. 10 has an additional step F. In step F, the main control unit 19 measures the vibration amount of the air pad. For example, by using the alignment detector 10 as a vibration amount measuring unit and measuring the positional deviation between the mold 8 and the substrate 3, the vibration amount of the air pad can be measured. If the vibration amount exceeds the allowable value, in step B, the main control unit 19 controls the adjustment unit 51 via the pressure control unit 52 to switch the air pad to a low pressure. If the amount of vibration is less than the allowable value, it is not necessary to perform steps B and C, and steps B and C are skipped. This is because the time until the positioning of the substrate 3 and the mold 8 is shortened when the air pad has higher rigidity. According to the example of FIG. 10, switching the air pad to a low pressure can be reduced as much as possible, which is advantageous in improving the throughput of the apparatus.

  In the example of FIG. 11, a process G is added to the example of FIG. As the pressure of the air pad is lowered in step B, the flying position of the air pad can change. In the present specification, “floating” does not mean that the X bottom air pads 30a to 30d and the Y bottom air pads 29a to 29d are lifted in the Z-axis direction from the guide surfaces. In this specification, “floating” is a concept including that the Y horizontal air pads 36a, 36c and the X horizontal air pads 31a, 31b, 31c float in the X direction or the Y direction from their guide surfaces due to the supply pressure of air. For example, in the case of a one-side constrained air pad, the flying position is offset at a level of 1000 nm, and even a double-side constrained air pad can be offset at a level of several tens to several hundreds of nanometers. Therefore, for example, when the pressure of the Y horizontal air pads 36a and 36c is changed from high pressure to low pressure, the floating position of the Y horizontal air pads 36a and 36c, which are both restrained air pads (the floating amount in the X direction with respect to the side surface of the X slider 12), , And can be offset at a level of several tens to several hundreds of nm. When the flying positions of the Y horizontal air pads 36a and 36c are offset, the position of the Y slider 4 with respect to the X slider 12 is shifted by several tens to several hundreds of nanometers in the X direction. If the position of the Y slider 4 is shifted, the position of the substrate 3 on the Y slider is shifted, and therefore the positional relationship between the substrate 3 and the mold 8 is shifted.

  Therefore, in step G, the main control unit 19 measures the air pad flying position and corrects the command value for the stage position, thereby reducing the positional deviation between the substrate 3 and the mold 8. This is because if the positional deviation between the substrate 3 and the mold 8 is large, the throughput is reduced due to the viscoelasticity of the imprint material. The measurement of the flying position of the Y horizontal air pads 36a and 36c is performed by, for example, the flying position measurement sensor 37. A measurement target 38 is disposed on the X slider 12, and the position of the measurement target 38 in the X direction is measured by the flying position measurement sensor 37. Since the flying position measurement sensor 37 only needs to be able to measure displacement in one or more axes, a sensor such as a capacitance sensor or a laser displacement meter can be used.

  Similarly, a floating position measurement sensor for measuring the floating position of the X horizontal air pads 31a, 31b, 31c may be arranged. A floating position measurement sensor is arranged on the X slider 12 and the position of the surface plate 13 in the Y direction is measured, thereby measuring the offset of the floating position of the X horizontal air pads 31a, 31b, and 31c by changing the supplied pressure. be able to.

  It is also possible to measure the offset of the flying position using the measuring instrument MD. With respect to the Y direction, the offset of the floating positions of the Y lateral air pads 36a and 36c can be measured by making the third measuring instrument MD3 an encoder system capable of observing the two directions of XY. Regarding the X direction, by making at least one of the first measuring instrument MD1 and the second measuring instrument MD2 an encoder system capable of observing two XY directions, the offset of the floating position of the X lateral air pads 31a, 31b, 31c can be reduced. It becomes possible to measure. Further, the influence of posture fluctuation can also be measured by a displacement sensor (not shown) that measures the positions of the Y bottom air pads 29a, 29b, 29c, 29d of the Y slider 4 and the surface plate 13. Thereby, an offset can be measured with high accuracy.

  Next, the example of FIG. 12 will be described. In FIG. 12, there are additional steps H, I, and J. After confirming that the pressure of the air pad is low in the process C, in the process H, the main control unit 19 measures the positional deviation between the mold 8 and the substrate 3 by using, for example, the alignment detector 10. Measure the vibration amount of the air pad. If the amount of vibration exceeds the allowable value, the process proceeds to step I. If the amount of vibration does not exceed the allowable value, the process proceeds to step J.

  In step I, the main control unit 19 controls the adjustment unit 51 via the pressure control unit 52 to reduce the minute vibration of the air pad, and changes the current pressure of the air pad to a lower pressure. Thereafter, the process returns to Step C, and Steps C, H, and I are repeated until the amount of vibration falls below the allowable value, and the pressure of the air pad is lowered stepwise.

  In step J, the pressure value when the vibration amount of the air pad becomes equal to or less than the allowable value is recorded in, for example, a memory (not shown) in the main control unit 19. In the next shot area, the pressure setting value is read from the memory and reflected in the pressure setting value of the air pad. This improves the throughput in the second and subsequent shot areas.

  The example of FIG. 13 is a combination of the example of FIG. 10 and the example of FIG. A process L is added to FIG. In step F, if the measured vibration amount is less than the allowable value, steps B to G are skipped, and the process proceeds to step 8. According to the example of FIG. 13, the number of times of pressure adjustment of the air pad can be reduced as much as possible, which is advantageous in improving the throughput of the apparatus.

  Each example of the air pad pressure control described above can be applied not only to the Y lateral air pads 36a and 36c but also to the X lateral air pads 31a, 31b and 31c, the X bottom air pads 30a to 30d, and the Y bottom air pads 29a to 29d as described above. It is. In consideration of the fact that the vibration in the XY direction is more likely to affect the overlay error than the vibration in the Z direction, the above-described air pad pressure control can be performed in the following priority order.

(1) Y-side air pads 36a, 36c (the air pads closer to the substrate among the air pads restraining the horizontal direction)
(2) X horizontal air pads 31a, 31b, 31c (the air pads far from the substrate among the air pads restraining the horizontal direction)
(3) X bottom air pads 30a, 30b, 30c, 30d, Y bottom air pads 29a, 29b, 29c, 29d

<Embodiment of article manufacturing method>
Hereinafter, the article manufacturing method will be described. Here, as an example, an article manufacturing method for manufacturing devices (semiconductor integrated circuit elements, liquid crystal display elements, etc.) as articles will be described. The article manufacturing method includes a step of forming a pattern on a substrate (wafer, glass plate, film-like substrate) using a lithography apparatus such as the above-described imprint apparatus. Further, the manufacturing method may include a step of processing (for example, etching) the substrate on which the pattern is formed. In the case of manufacturing other articles such as patterned media (recording media) and optical elements, the manufacturing method may include other processes for processing a substrate on which a pattern is formed instead of etching.

  The pattern of the cured product formed using the imprint apparatus is used permanently on at least a part of various articles or temporarily used when manufacturing various articles. The article is an electric circuit element, an optical element, a MEMS, a recording element, a sensor, or a mold. Examples of the electric circuit elements include volatile or nonvolatile semiconductor memories such as DRAM, SRAM, flash memory, and MRAM, and semiconductor elements such as LSI, CCD, image sensor, and FPGA. Examples of the mold include an imprint mold.

  The pattern of the cured product is used as it is as a constituent member of at least a part of the article, or temporarily used as an imprint material mask. After etching or ion implantation is performed in the substrate processing step, the imprint material mask is removed.

IMP: imprint apparatus, MP: movable part, 3: substrate, 4: Y slider, 9: imprint head, 10: alignment detector, 11: curing part, 12: X slider, 13: surface plate

Claims (13)

An imprint apparatus that forms a pattern of an imprint material on a processing area of a substrate using a mold,
A substrate holding part that is movable while holding the substrate;
A hydrostatic bearing that supports the substrate holding portion in a non-contact manner with respect to the guide surface by jetting gas toward the guide surface;
An adjustment unit for adjusting the pressure of the gas ejected by the hydrostatic bearing;
Have
The imprinting unit reduces the pressure of the gas after the region to be processed and the mold face each other and until the alignment between the mold and the region to be processed is completed. apparatus. A surface plate on which the substrate holder is mounted;
A first slider for moving the substrate holding portion on a first guide surface constituted by an upper surface of the surface plate along a second guide surface orthogonal to the first guide surface;
While being guided by the first slider, the substrate holding portion is moved along a third guide surface constituted by a side surface of the first slider which is orthogonal to the first guide surface and the second guide surface. Two sliders,
The imprint apparatus according to claim 1, further comprising:   The hydrostatic bearing includes a hydrostatic bearing that ejects gas toward the second guide surface or the third guide surface, and the adjustment unit includes the hydrostatic bearing that is configured to be the second guide surface or the third guide. The imprint apparatus according to claim 2, wherein the pressure of the gas ejected toward the surface is adjusted. A supply unit for supplying the imprint material to the substrate;
The second guide surface is provided along a direction from the position where the substrate holding part faces the supply part to the position facing the mold,
The hydrostatic bearing includes a hydrostatic bearing that ejects gas toward the third guide surface, and the adjustment unit adjusts the pressure of the gas that the hydrostatic bearing ejects toward the third guide surface. The imprint apparatus according to claim 2. The hydrostatic bearing is
A first hydrostatic bearing that supports the first slider in a non-contact manner with respect to the first guide surface by ejecting a gas toward the first guide surface;
A second hydrostatic bearing that supports the first slider in a non-contact manner with respect to the second guide surface by ejecting a gas toward the second guide surface;
A third hydrostatic bearing that supports the second slider in a non-contact manner with respect to the third guide surface by jetting gas toward the third guide surface;
A fourth hydrostatic bearing that supports the second slider in a non-contact manner with respect to the first guide surface by jetting gas toward the first guide surface;
Including
The adjustment unit is configured to include at least one of the first to fourth hydrostatic bearings after the region to be processed and the mold face each other and until the alignment between the mold and the region to be processed is completed. The imprint apparatus according to claim 2, wherein the pressure of the gas is reduced.   6. The apparatus according to claim 1, further comprising a correction unit that corrects a command value of the position for the alignment based on an offset of a floating position by the hydrostatic bearing caused by reducing the pressure. The imprint apparatus according to any one of the above.   The imprint apparatus according to claim 6, further comprising an offset measurement unit that measures the offset. After completion of the alignment, further comprising a curing portion that cures the imprint material,
8. The imprint apparatus according to claim 1, wherein the adjustment unit increases the reduced pressure after the curing of the imprint material by the curing unit is completed. A pressure sensor for detecting the pressure;
A control unit that performs the alignment after confirming the decrease in the pressure using the pressure sensor;
The imprint apparatus according to claim 1, further comprising: A load cell for detecting a load applied between the mold and the imprint material on the substrate;
The said adjustment part reduces the said pressure, after the contact with the said mold and the imprint material on the said board | substrate is confirmed using the said load cell. Any one of Claim 1 thru | or 9 characterized by the above-mentioned. The imprint apparatus described. A vibration amount measuring unit for measuring a vibration amount of the hydrostatic bearing;
The said adjustment part reduces the said pressure, when the vibration amount measured by the said vibration amount measurement part exceeds an allowable value. The in of any one of Claim 1 thru | or 10 characterized by the above-mentioned. Printing device. When the vibration amount measured by the vibration amount measurement unit exceeds the allowable value, the adjustment unit adjusts the pressure until the vibration amount measured by the vibration amount measurement unit becomes equal to or less than the allowable value. The imprint apparatus according to claim 11, wherein the imprint apparatus is lowered. Forming a pattern on a substrate using the imprint apparatus according to claim 1;
Processing the substrate on which the pattern is formed;
An article manufacturing method comprising:

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