CN112334836A - Exposure apparatus and height adjustment method - Google Patents

Abstract

The height of the light irradiation part can be accurately adjusted. The rotation driving part is driven to rotate the pinion (161b), so that the support part (15a) provided with the rack (161a) meshed with the pinion (161b) moves along the height direction. In addition, current flows through a coil of an electromagnet included in a permanent electromagnet (163) including a permanent magnet and an electromagnet, and the permanent electromagnet (163) is attracted to the support section (15a), whereby the support section side sliding surface (161e) and the column side sliding surface (161d) are brought into close contact, and the support section (15a) is fixed by a frictional force between the support section side sliding surface (161e) and the column side sliding surface (161 d).

Description

Exposure apparatus and height adjustment method

Technical Field

The invention relates to an exposure apparatus and a height adjustment method.

Background

Patent document 1 discloses a drawing device in which a ball screw is engaged with one end of a holding plate, and a servo motor connected to the ball screw moves a drawing head in a vertical direction within a predetermined range.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 9-320943

Disclosure of Invention

Problems to be solved by the invention

However, in the invention described in patent document 1, since the ball screw is used for moving the drawing head, there is a problem that a follow-up error (floating of the advance speed of the female screw member with respect to one rotation of the screw) occurs and the drawing head cannot be moved accurately.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an exposure apparatus and a height adjustment method capable of accurately adjusting the height of an optical device that irradiates light.

Means for solving the problems

In order to solve the above problem, an exposure apparatus according to the present invention includes, for example: a substrate holding section for placing a substrate; a frame body having a substantially rod-shaped support portion formed of a magnetic material and provided so that a longitudinal direction thereof is substantially horizontal, and a rod-shaped column provided so that a longitudinal direction thereof is substantially vertical at both ends of the support portion, the support portion having a support portion side sliding surface formed thereon, the column having a column side sliding surface formed thereon at a position facing the support portion side sliding surface; a moving mechanism that moves the support portion in a vertical direction, and that has a rack provided on the support portion, a pinion rotatably provided on the column and meshed with the rack, and a rotation driving portion that rotates the pinion; an optical device that is provided on the support portion and irradiates the substrate with light; a permanent electromagnet provided to the column and having a permanent magnet and an electromagnet; and a control unit that drives the rotation driving unit to move the support unit, and that causes the permanent magnet to attract the support unit by applying a current to a coil of the electromagnet, and causes the permanent electromagnet to attract the support unit to bring the support unit-side sliding surface into close contact with the column-side sliding surface, and that fixes the support unit to the column by a frictional force between the support unit-side sliding surface and the column-side sliding surface.

According to the exposure apparatus of the present invention, the rotation driving section is driven to rotate the pinion, thereby moving the support section provided with the rack that meshes with the pinion in the height direction. Further, a current flows through a coil of an electromagnet included in a permanent electromagnet including a permanent magnet and an electromagnet, and the permanent electromagnet attracts the support portion, whereby the support portion side sliding surface is brought into close contact with the column side sliding surface, and the support portion is fixed by a frictional force between the support portion side sliding surface and the column side sliding surface. Thus, the height of the optical device can be accurately adjusted. Further, since the permanent electromagnet is used for the adsorption of the support portion, the energization time is shortened, and the deformation, expansion, and the like of the support portion due to heat are not generated, so that the height adjustment of the optical device can be accurately performed.

Here, the exposure apparatus may include a measurement unit that is provided on the support unit and includes a scale provided substantially in a vertical direction and a head that reads a value of the scale and outputs position information, wherein when the support unit moves, the permanent electromagnet may attract the support unit with a second attracting force that is weaker than a first attracting force that is an attracting force when the moving mechanism does not move the support unit, and wherein the measurement unit may continuously measure a height of the support unit, and wherein the support unit side sliding surface slides along the column side sliding surface. Accordingly, the support portion does not tilt when the support portion side sliding surface and the column side sliding surface are brought into close contact with each other, and therefore, a measurement error of the measurement portion due to the tilt of the support portion can be eliminated.

Here, the second adsorption force may be approximately 20% to approximately 30% of the first adsorption force. Thereby, the difference between the measurement result measured by the measurement portion when the support portion is sucked with the second suction force and the measurement result measured by the measurement portion when the support portion is sucked with the first suction force is minimized.

Here, the exposure apparatus may include: a substantially thin plate-shaped guide member provided between the support portion and the optical device; and a driving portion that is provided in the housing and moves the optical device in a vertical direction, wherein the support portion has a plate-like portion that is disposed substantially horizontally, a circular hole that penetrates in a substantially vertical direction is formed in the plate-like portion, the guide member has a substantially circular plate shape in a plan view and is provided in the plate-like portion so as to cover the circular hole, a mounting hole is formed in a substantially center of the guide member, the mounting hole and the circular hole are disposed substantially concentrically, and the optical device is inserted into the mounting hole so that an optical axis thereof substantially coincides with a center of the mounting hole and is fixed to the guide member. This can reduce the optical axis jitter to several nm or less when the optical device is moved in the height direction by the driving unit.

Here, the exposure apparatus may include: a moving unit that moves the substrate holding unit in a scanning direction; and a measuring unit provided in the support unit and measuring a distance to the substrate, wherein the control unit measures the distance to the substrate by the measuring unit while moving the substrate holding unit in the scanning direction by the moving unit, obtains a central value from a maximum value and a minimum value of the distance to the substrate, and obtains a driving amount of the driving unit based on the central value. Thus, even if the height of the substrate changes, the optical device can be always brought into focus on the substrate.

Here, the optical apparatus may include an AF processing unit that includes: a light source for AF that irradiates downward light; and an AF sensor that receives incident light, wherein the control unit moves the support unit while operating the AF processing unit, and causes the support unit-side sliding surface and the column-side sliding surface to be in close contact with each other when the optical device is located at a position determined to be in focus. Thus, even if the height of the substrate changes, the optical device can be always brought into focus on the substrate.

In order to solve the above problem, a height adjustment method according to the present invention is a height adjustment method for adjusting a height of a support portion using, for example, a device including: a substrate holding section for placing a substrate; a frame body having a substantially rod-shaped support portion formed of a magnetic material and provided so that a longitudinal direction thereof is substantially horizontal, and a rod-shaped column provided so that a longitudinal direction thereof is substantially vertical at both ends of the support portion, the support portion having a support portion side sliding surface, the column having a column side sliding surface at a position facing the support portion side sliding surface; a moving mechanism that moves the support portion in a vertical direction and that has a rack provided substantially in the vertical direction on the support portion, a pinion rotatably provided on the column and meshed with the rack, and a rotation driving portion that rotates the pinion; a measuring unit provided to the support unit; an optical device that is provided on the support portion and irradiates the substrate with light; and a permanent electromagnet provided to the column and having a permanent magnet and an electromagnet, the height adjustment method including the steps of: passing a current through a coil of the electromagnet to cause the permanent electromagnet to attract the support portion with a second attracting force, thereby bringing the support portion side sliding surface into contact with the column side sliding surface; driving the rotation driving unit to rotate the pinion gear while measuring the height of the support unit by the measuring unit, thereby moving the support unit in a height direction; and passing a current through the coil to cause the permanent electromagnet to attract the support portion with a first attraction force stronger than the second attraction force, and to bring the support portion-side sliding surface into close contact with the column-side sliding surface to fix the support portion to the column. Accordingly, since the support portion does not tilt when the support portion is sucked by the second suction force and when the support portion is sucked by the first suction force, a measurement error of the measurement portion due to the tilt of the support portion can be eliminated.

Effects of the invention

According to the present invention, the height of the light irradiation section can be accurately adjusted.

Drawings

Fig. 1 is a perspective view showing an outline of an exposure apparatus 1 according to a first embodiment.

Fig. 2 is a schematic diagram showing a case where the measurement unit 40 and the laser interferometer 50 measure the position of the mask holding unit 20.

Fig. 3 is a perspective view schematically showing the support portion 15a of the housing 15, and is a view seen from the back side (+ x side).

Fig. 4 is a perspective view schematically showing the support portion 15a of the housing 15, and is a view seen from the front side (-x side).

Fig. 5 is a view showing an outline of the frame 15 cut at the plane C of fig. 3.

Fig. 6 is a main part perspective view showing an outline of the light irradiation section 30 a.

Fig. 7 is a side view schematically showing the driving portion 39 a.

Fig. 8 (a) is a diagram showing an outline of the guide member 70, and fig. 8 (B) is a diagram showing an outline of the guide member 70A.

Fig. 9 (a) is a diagram showing a positional relationship between the base plate 151 and the guide member 70 when the guide member 70 is attached to the base plate 151, and fig. 9 (B) is a diagram showing a positional relationship between the support plate 153 and the guide member 70A when the guide member 70A is attached to the support plate 153.

Fig. 10 is an exploded perspective view of a mounting structure for mounting the light irradiation unit 30a to the support plate 153.

Fig. 11 is a diagram showing a state in which the light irradiation unit 30a is attached to the housing 15.

Fig. 12a is a diagram showing a state in which the light irradiation section 30a does not move (stroke center), fig. 12B is a diagram showing a state in which the light irradiation section 30a moves downward (stroke lower end), and fig. 12C is a diagram showing a state in which the light irradiation section 30a moves upward (stroke upper end).

Fig. 13 is a block diagram showing an electrical configuration of the exposure apparatus 1.

Fig. 14 is a flowchart showing the flow of the height adjustment process of the exposure apparatus 1.

Fig. 15 shows an example of the measurement result in step S20.

Fig. 16 is a diagram schematically showing a state when the support portion 15a is moved up and down, fig. 16 a shows a case where the support portion 15a is sucked (this embodiment), and fig. 16B and C show a case where the support portion 15a is not sucked.

Detailed Description

The present invention will be described in detail below with reference to the drawings by taking as an example an embodiment applied to an exposure apparatus that generates a photomask by irradiating a photosensitive substrate (for example, a glass substrate) held in a substantially horizontal direction with light such as laser light while moving the substrate in a scanning direction. In the drawings, the same elements are denoted by the same reference numerals, and redundant description thereof is omitted.

For example, a photosensitive substrate having a very small thermal expansion coefficient (e.g., about 5.5X 10)^-7approximately/K) quartz glass. The photomask generated by the exposure apparatus is, for example, an exposure mask used for manufacturing a substrate for a liquid crystal display device. The photomask forms one or a plurality of transfer patterns for an image device on a large-sized substantially rectangular substrate having one side exceeding, for example, 1m (e.g., 1400mm × 1220 mm). Hereinafter, the term "mask M" is used as a concept including a photosensitive substrate before, during, and after processing.

However, the exposure apparatus of the present invention is not limited to the mask manufacturing apparatus. The exposure apparatus of the present invention is a concept including various apparatuses that irradiate light (including laser light, UV, polarized light, and the like) while moving a substrate held in a substantially horizontal direction in a scanning direction. The optical device of the present invention is not limited to the light irradiation unit that irradiates the photosensitive substrate with light.

Fig. 1 is a perspective view showing an outline of an exposure apparatus 1 according to a first embodiment. The exposure apparatus 1 mainly includes a stage 11, a plate-like portion 12, guide rails 13, 14, a housing 15, a mask holding portion 20, a light irradiation portion 30, a measurement portion 40 (see fig. 2), a laser interferometer 50 (see fig. 2), and measurement portions 61(61a, 61d, 61 g). In fig. 1, a part of the structure is not illustrated. The exposure apparatus 1 is kept at a constant temperature by a temperature adjustment unit, not shown, which covers the entire apparatus.

The platform 11 is a member having a substantially rectangular parallelepiped shape (thick plate shape), and is formed of, for example, rock (e.g., granite) or a casting having a low expansion rate (e.g., a nickel-based alloy). The platform 11 has a substantially horizontal (substantially parallel to the xy plane) upper surface 11a on the upper side (+ z side).

The stage 11 is placed above a plurality of vibration isolation tables (not shown), and the plurality of vibration isolation tables (not shown) are placed on a mounting surface (e.g., a floor). Thereby, the stage 11 is mounted on the mounting surface via the vibration isolation table. The vibration canceling stage is already known, and thus a detailed description is omitted. It should be noted that the vibration isolation table is not essential. A loader (not shown) for setting the mask M to the mask holding portion 20 is provided on the + x side of the stage 11.

The guide rail 13 is a ceramic elongated plate-like member, and is fixed to the upper surface 11a of the stage 11 so that the longitudinal direction thereof extends along the scanning direction (x direction). The three guide rails 13 have substantially the same height (position in the z direction), and the upper surfaces thereof are formed with high accuracy and high flatness.

An end of the guide rail 13 on the loader side (+ x side) is disposed at an end of the upper surface 11a, and an end of the guide rail 13 on the side opposite to the loader (x side) is disposed inside the end of the upper surface 11 a.

The plate-like portion 12 is placed above the guide rail 13. The plate-like portion 12 is a substantially plate-like member made of ceramic, and has a substantially rectangular shape as a whole. A guide portion (not shown) is provided on the lower surface (-z side surface) of the plate-like portion 12 so that the longitudinal direction thereof is along the x direction. This restricts the movement direction of the plate-shaped portion 12 so that the plate-shaped portion 12 does not move in a direction other than the x direction.

A guide rail 14 is provided on the upper surface 12a of the plate-like portion 12. The guide rail 14 is fixed in such a manner that the longitudinal direction is along the y direction. The height of the guide rail 14 is substantially the same, and the upper surface is formed with high precision and high flatness.

The mask holding part 20 is substantially plate-shaped with a substantially rectangular shape in plan view, and has a thermal expansion coefficient of substantially 0.5 to 1 x 10^-7A low-expansion ceramic of/K. This can prevent the mask holding portion 20 from being deformed. The mask holding portion 20 may have a thermal expansion coefficient of approximately 5 × 10^-8An ultra low expansion/K glass-ceramic. In this case, even if a temperature change that cannot be completely controlled occurs, it is possible to reliably control the temperature changeDeformation of the mask holding portion 20 is prevented. The mask holding portion 20 may be formed of a material that expands and contracts similarly to the mask M.

The mask holding portion 20 is placed above the guide rail 14. In other words, the mask holding portion 20 is provided on the upper surface 11a via the plate-shaped portion 12 and the guide rails 13 and 14.

A guide portion (not shown) is provided on the lower surface of the mask holding portion 20 so that the longitudinal direction thereof extends along the y direction. Thus, the movement direction of the mask holding portion 20 is regulated so that the mask holding portion 20, i.e., the plate-like portion 12 does not move in the direction other than the y direction.

Thus, the mask holding portion 20 (the plate-like portion 12) is provided movably in the x direction along the guide rail 13, and the mask holding portion 20 is provided movably in the y direction along the guide rail 14.

The mask holding portion 20 has a substantially horizontal upper surface 20 a. A mask M (not shown) is placed on the upper surface 20 a. Further, strip mirrors 21, 22, and 23 (see fig. 2) are provided on the upper surface 20 a.

The exposure apparatus 1 includes driving units 81 and 82 (see fig. 13). The driving units 81 and 82 are, for example, linear motors. The driving unit 81 moves the mask holding unit 20 (the plate-like unit 12) in the x direction along the guide rail 13, and the driving unit 82 moves the mask holding unit 20 in the y direction along the guide rail 14. Various known methods can be used for the driving units 81 and 82 to move the plate-like portion 12 and the mask holding portion 20.

The platform 11 is provided with a frame 15. The frame 15 is made of a magnetic material, for example, a casting (for example, a nickel-based alloy) having a low expansion rate. The frame 15 includes a support portion 15a and two posts 15c that support the support portion 15a at both ends. The frame body 15 holds the light irradiation section 30 above the mask holding section 20 (+ z direction). The light irradiation unit 30 is attached to the support unit 15 a. The frame 15 will be described in detail later.

The light irradiation unit 30 irradiates light (laser light in the present embodiment) to the mask M. The light irradiation sections 30 are disposed at constant intervals (for example, at intervals of approximately 200mm) along the y direction. In the present embodiment, there are 7 light irradiation units 30a, 30b, 30c, 30d, 30e, 30f, and 30 g. The moving mechanism 161 (described in detail later) moves the entire light irradiation sections 30a to 30g in the vertical direction (z direction) within a range of about 10mm so that the focal positions of the light irradiation sections 30a to 30g are aligned with the upper surface of the mask M. The driving unit 39(39a (see fig. 6) to 39g, which will be described later) finely moves the light irradiation units 30a to 30g in the z direction within a range of about 30 μm (micrometers) in order to finely adjust the focal positions of the light irradiation units 30a to 30 g. The light irradiation section 30 will be described in detail later.

The light irradiation units 30a to 30g are provided with reading units, not shown. The reading section reads a pattern formed on the mask M.

The measurement unit 40 (see fig. 2) is, for example, a linear encoder, and the laser interferometer 50 for measuring the position of the mask holding unit 20 includes laser interferometers 51 and 52 (not shown in fig. 1, see fig. 2). The laser interferometer 51 is provided on a column provided on the-y side of the housing 15. The laser interferometer 52 (not shown in fig. 1) is provided on the + x-side surface of the stage 11.

Fig. 2 is a schematic diagram showing a case where the measurement unit 40 and the laser interferometer 50 measure the position of the mask holding unit 20. In fig. 2, only a part of the guide rails 13 and 14 is illustrated. In fig. 2, only the light irradiation units 30a and 30g are shown, and the light irradiation units 30b to 30f are not shown.

The measuring unit 40 has position measuring units 41 and 42. The position measuring units 41 and 42 have scales 41a and 42a and detection heads 41b and 42b, respectively.

The scale 41a is provided on the + y-side end surface of the guide rail 13 on the + y side and the-y-side end surface of the guide rail 13 on the-y side. The detection heads 41b are provided on the + y-side and-y-side end surfaces of the plate-like portion 12 (not shown in fig. 2). In fig. 2, the scale 41a and the detection head 41b on the + y side are not shown.

The scale 42a is provided on the + x-side end surface of the + x-side guide rail 14 and the-x-side end surface of the-x-side guide rail 13. The detection heads 42b are provided on the + x side and-x side end surfaces of the mask holding portion 20. In fig. 2, the scale 42a and the detection head 42b on the-x side are not shown.

The scales 41a, 42a are, for example, laser hologram scales, and scales are formed at a pitch of 0.512 μm (nm). The detection heads 41b and 42b emit light (e.g., laser light) and acquire light reflected by the scales 41a and 42a, and the signals generated thereby are divided by 512 to obtain 1nm and are divided by 1024 to obtain 0.5 nm. The position measuring units 41 and 42 are already known, and therefore, detailed description thereof is omitted.

The light irradiation unit 30a is provided with a mirror 55a having a reflection surface substantially parallel to the xz plane. The light irradiation unit 30g is provided with mirrors 55b and 55c having reflection surfaces substantially parallel to the xz plane. The mirrors 55a, 55b, and 55c are provided so as not to overlap with each other in position in the x direction.

The light irradiation unit 30a is provided with a mirror 56a having a reflection surface substantially parallel to the yz plane. The light irradiation unit 30g is provided with a mirror 56g having a reflection surface substantially parallel to the yz plane.

The laser interferometers 51 and 52 irradiate 4 laser beams. The laser interferometer 51 includes laser interferometers 51a, 51b, and 51 c. The laser interferometer 52 has laser interferometers 52a and 52 g.

In fig. 2, the path of the laser light is indicated by a two-dot chain line. Two of the light beams radiated from the laser interferometers 51a, 51b, 51c are reflected by the strip mirror 23, and the reflected light beams are received by the laser interferometers 51a, 51b, 51 c.

The remaining two beams of light irradiated from the laser interferometer 51a are reflected by the reflecting mirror 55a, and the reflected light is received by the laser interferometer 51 a. The remaining two beams of light irradiated from the laser interferometer 51b are reflected by the reflecting mirror 55b, and the reflected light is received by the laser interferometer 51 b. The remaining two beams of light irradiated from the laser interferometer 51c are reflected by the reflecting mirror 55c, and the reflected light is received by the laser interferometer 51 c.

The laser interferometers 51a to 51c can measure the position of the strip mirror 23 with reference to the positions of the mirrors 55a to 55c, respectively, to thereby measure the positional relationship in the y direction between the light irradiation sections 30a and 30g and the mask holding section 20.

Two of the light irradiated from the laser interferometer 52a are reflected by the bar mirror 22, and the reflected light is received by the laser interferometer 52 a. Two of the light irradiated from the laser interferometer 52g are reflected by the bar mirror 21, and the reflected light is received by the laser interferometer 52 g.

The remaining two beams of light irradiated from the laser interferometer 52a are reflected by the reflecting mirror 56a, and the reflected light is received by the laser interferometer 52 a. The remaining two beams of light irradiated from the laser interferometer 52g are reflected by the reflecting mirror 56g, and the reflected light is received by the laser interferometer 52 g.

The laser interferometers 52a and 52g measure the positions of the strip mirrors 21 and 22 with reference to the positions of the mirrors 56a and 56g, respectively, to thereby measure the positional relationship in the x direction between the light irradiation parts 30a to 30g and the mask holding part 20.

In the present embodiment, no mirror is provided in the light irradiation sections 30b to 30f, and no laser interferometer for measuring the position of the mirror is provided. This is because the jitter of the optical axis when the light irradiation units 30a to 30g are moved in the z direction within a range of about 30 μm is as small as several nm or less (described in detail later), and the positions of the light irradiation units 30b to 30f are obtained by interpolation based on the positions of the light irradiation units 30a and 30 g. This makes it possible to reduce the size of the device and to reduce the cost.

Next, the housing 15 will be explained. Fig. 3 and 4 are schematic perspective views showing the support portion 15a of the housing 15. Fig. 3 is a view from the back side (-x side), and fig. 4 is a view from the front side (+ x side). Fig. 3 and 4 illustrate the support portion 15a slightly apart from the post 15c for the sake of explanation, but the support portion 15a is actually adjacent to the post 15 c.

The support portion 15a has a substantially rod shape having a substantially rectangular cross-sectional shape, and a cavity is formed therein. The support portion 15a is disposed so that the longitudinal direction is substantially horizontal (y direction in this case). The posts 15c are provided at both ends of the support portion 15a, respectively.

The support portion 15a mainly includes a bottom plate 151, a support plate 153, side plates 152 and 154 provided on both sides of the bottom plate 151 and the support plate 153, and a partition wall 159. The bottom plate 151 and the support plate 153 are disposed substantially horizontally, and the side plates 152 and 154 are disposed substantially vertically.

In the present embodiment, the plate thicknesses of the bottom plate 151, the support plate 153, and the side plates 152 and 154 are approximately 15mm to 20mm, and the y-direction lengths (W1 in fig. 9) of the bottom plate 151, the support plate 153, and the side plates 152 and 154 are approximately 2.2 m.

Circular holes 155a to 155g and 156a to 156g are formed in the y direction in the base plate 151 and the support plate 153, respectively. The circular holes 155a to 155g and 156a to 156g are holes that penetrate the base plate 151 and the support plate 153 in the substantially vertical direction, and are substantially circular in plan view. The centers of the circular holes 155a to 155g substantially coincide with the centers of the circular holes 156a to 156g in plan view.

Guide members 70 and 70A (described in detail later) are provided in the circular holes 155a to 155g and 156a to 156g so as to cover the circular holes 155a to 155g and 156a to 156g, respectively, and the light irradiation portions 30A to 30g are attached to the guide members 70 and 70A. In other words, the light irradiation portions 30A to 30g are provided in the housing 15 via the guide members 70 and 70A. The mounting structure for mounting the light irradiation units 30a to 30g to the housing 15 will be described in detail later.

Further, circular holes 157a to 157g are formed in the bottom plate 151 adjacent to the circular holes 155a to 155 g. A lens barrel of a reading unit (not shown) is inserted into the circular holes 157a to 157 g.

Holes 152a to 152i and 154a to 154i are formed in the side plates 152 and 154, respectively. The holes 152a to 152g and 154a to 154g are provided so as to overlap the circular holes 155a to 155g and 156a to 156g, respectively, at positions in the y direction. The holes 152a to 152g and 154a to 154g are used to attach the reading unit 60 to the circular holes 157a to 157 g. Holes 152h, 152i are disposed on either side of holes 152 a-152 g, respectively, and holes 154h, 154i are disposed on either side of circular holes 154 a-154 g, respectively. The frame 15 is a casting, and the holes 152a to 152i and 154a to 154i are used as casting holes for forming an internal space by discharging molding sand during casting.

The support portion 15a has a cavity inside, but a partition wall 159 is provided inside the support portion 15a for reinforcement. Partition 159 is a plate-shaped member, and has an end surface abutting against bottom plate 151, support plate 153, and side plates 152 and 154. Thus, there is no cavity inside the support portion 15a at the position where the partition wall 159 is provided, and vibration, deformation (flexure, torsion, etc.) of the support portion 15a is prevented.

The housing 15 has a moving mechanism 161 for moving the support portion 15a in the z direction along the column 15 c. The moving mechanism 161 moves the support portion 15a in the z direction within a range of about 10 mm. The moving mechanism 161 of the present embodiment includes: a rack 161a provided along the z-direction on an end surface substantially orthogonal to the longitudinal direction of the support portion 15 a; and a pinion gear 161b provided rotatably on the column 15 c; and a rotation driving unit 161f (see fig. 13) for rotating the pinion gear 161 b. The rack 161a is provided at substantially the center of an end surface substantially orthogonal to the longitudinal direction of the support portion 15a, and is fixed to the convex portion 158 protruding outward from the side surface of the support portion 15a using a screw or the like (not shown). The pinion gear 161b is rotatably provided on the column 15c and meshes with the rack gear 161 a.

Two permanent electromagnets 163 are provided on the column 15 c. The two permanent magnets 163 are provided on the column 15c and are disposed near both ends of the support portion 15a in the longitudinal direction. The permanent electromagnet 163 is provided along the side plate 154 adjacent to the end surface where the rack 161a is provided.

The permanent electromagnet 163 is a permanent electromagnetic type including a permanent magnet 163a (see fig. 13) and an electromagnet 163b (see fig. 13), and current is passed through a coil of the electromagnet 163b only during magnetization and demagnetization, thereby turning on and off the built-in permanent magnet 163 a. The low expansion alloy used for the frame 15 is a magnetic material and can be moved by the permanent electromagnet 163. Since the permanent magnet 163 is energized only for a short time (for example, about 0.2 second) at the time of on-off, almost no heat is generated. In addition, the magnetic force of the permanent magnet 163 after the permanent magnet is turned on does not change.

The permanent magnet 163 has an adjustment dial 163c (see fig. 13). The adjustment dial 163c adjusts the current flowing through the coil of the electromagnet 163b, and is configured to be capable of adjusting the current in 10 steps of 1 to 10, for example. In the present embodiment, when the value of the adjustment dial 163c is "10", the adsorption force with which the permanent electromagnet 163 adsorbs the support portion 15a is a first adsorption force (described in detail later), and when the value of the adjustment dial 163c is "2" or "3" (approximately 20% to approximately 30% of the current value when the value of the adjustment dial 163c is "10"), the adsorption force with which the permanent electromagnet 163 adsorbs the support portion 15a is a second adsorption force (described in detail later). Since the current value is proportional to the magnetic flux density and the attraction force, the magnetic flux density and the attraction force of the permanent magnet 163 change by adjusting the adjustment dial 163 c.

The support portion 15a is provided with a measurement portion 164. The measuring unit 164 includes a scale 164a (see fig. 5) provided substantially along the vertical direction, and a detection head 164b (see fig. 5) that reads the value of the scale 164a and outputs position information. The scale 164a is, for example, a laser hologram scale, as with the scales 41a and 42 a. The detection head 164b irradiates light (for example, laser light) as in the detection heads 41b and 42b, acquires light reflected by the scale 164a, and obtains position information based on a signal generated thereby. The scale 164a is provided on the side plate 152 on the opposite side to the side plate 154.

The side plate 152 is provided with a measuring unit 61(61a, 61d, 61g) for measuring the distance to the mask M. The measuring units 61a, 61d, and 61g are, for example, displacement sensors that detect the height of the object (here, the mask M) based on laser light emitted from the sensors. The measuring section 61a is provided adjacent to the light irradiation section 30a, the measuring section 61d is provided adjacent to the light irradiation section 30d, and the measuring section 61g is provided adjacent to the light irradiation section 30 g.

Fig. 5 is a view showing an outline of the frame 15 cut at the plane C of fig. 3. The column 15c is provided with a projection 161 c. The surface on the + x side of the convex portion 161c is a sliding surface 161d, and is subjected to grinding, i.e., scraping, for reducing frictional resistance.

The surface of the support portion 15a on the-x side is a sliding surface 161 e. The sliding surface 161e is provided at a position facing the sliding surface 161 d. The sliding surface 161e is scraped off in the same manner as the sliding surface 161 d. Between the sliding surface 161e and the sliding surface 161d, an oil film of about several μm is formed by the lubricating oil accumulated in the minute concave and convex portions of the sliding surfaces 161d and 161 e. In the present embodiment, a mineral oil having a low viscosity and being liquid at normal temperature is used as the lubricating oil.

The support portion 15a to which the rack 161a is fixed is moved up and down by rotating the pinion gear 161b provided on the column 15 c. When the moving mechanism 161 moves the support portion 15a up and down, the sliding surface 161d and the sliding surface 161e smoothly slide with an oil film formed between the sliding surface 161d and the sliding surface 161 e.

When the rack 161a is viewed along the y direction, the teeth of the rack 161a are located on the center line c in the x direction of the support portion 15 a. In other words, the teeth of the rack 161a are located on a line that passes through the center of gravity of the support portion 15a and is substantially parallel to the z direction. Therefore, when the pinion 161b rotates to move the rack 161a (the support portion 15a) up and down, no moment is generated.

As shown in fig. 3 and 4, a sliding surface 161d on which scraping processing is performed is also formed on the column 15c on the side where the rack 161a and the pinion 161b are not provided. A sliding surface 161e (see fig. 5) on which scraping processing is performed is formed in the support portion 15a so as to abut against the sliding surface.

An elastic member 160 is provided along the column 15c at an end of the support portion 15 a. In fig. 3 and 4, only the elastic member 160 provided at the end on the-y side is shown, and the elastic member 160 provided at the end on the + y side is not shown. As shown in fig. 5, the elastic member 160 is provided on the lower side of the support portion 15 a. A positioning member 162 is provided between the elastic member 160 and the support portion 15 a. By inserting the elastic member 160 into the recess 162a formed in the bottom surface of the positioning member 162, the position of the elastic member 160 in the xy direction is determined, and the elastic member 160 can expand and contract along with the vertical movement of the support portion 15 a. Thus, the elastic members 160 provided at both ends of the support portion 15a support the weight of the support portion 15 a. The support portion 15a is approximately 660kg to 700kg, and the elastic member 160 can support approximately 600kg of weight.

The weight of the support portion 15a which is not supported by the elastic member 160 is supported by the frictional force between the sliding surface 161d and the sliding surface 161 e. The permanent electromagnet 163 is provided on the post 15c, and attracts the support portion 15a by passing a current through a coil of the electromagnet 163b (see fig. 13).

When the moving mechanism 161 does not move the support portion 15a up and down along the column 15c, the permanent electromagnet 163 sucks the support portion 15a with the first suction force, and thereby the rack 161a as the support portion 15a and the sliding surface 161e move leftward in fig. 5 (see the arrow in fig. 5), and the sliding surface 161d comes into close contact with the sliding surface 161 e. The first attraction force is substantially 12000N, and the magnetic flux density of the permanent magnet 163 when the permanent magnet 163 attracts the support portion 15a with the first attraction force is substantially 0.3T (tesla). Further, the surface pressure generated between the sliding surface 161d and the sliding surface 161e when the permanent electromagnet 163 sucks the support portion 15a with the first suction force is substantially 0.8 MPa.

By increasing the surface pressure generated between the sliding surface 161d and the sliding surface 161e in this way and bringing the sliding surface 161d and the sliding surface 161e into close contact (strong compression), the oil film formed between the sliding surface 161d and the sliding surface 161e is removed. As a result, friction is generated between the sliding surface 161d and the sliding surface 161 e.

The coefficient of friction between the sliding surface 161d and the sliding surface 161e when the oil film is removed is 0.1 to 0.2, and when the attraction force of the permanent electromagnet 163 is 1500kg, the weight of 150kg is supported by the friction between the sliding surface 161d and the sliding surface 161 e. Since the sliding surfaces are present at two locations on both sides of the support portion 15a, the weight ta (approximately 60kg to 100kg) of the support portion 15a that cannot be supported by the elastic member 160 can be supported by the frictional force. In this way, when the moving mechanism 161 does not move the support portion 15a up and down, the support portion 15a is supported so that the position of the support portion 15a in the height direction (z direction) does not change.

When the moving mechanism 161 moves the support portion 15a up and down along the column 15c, the permanent electromagnet 163 sucks the support portion 15a with a weak force (second sucking force). The suction force (second suction force) when the upper support portion 15a moves up and down is weaker than the suction force (first suction force) when the support portion 15a does not move up and down. In the present embodiment, the second adsorption force is approximately 20% to approximately 30% of the first adsorption force. The second attraction force is approximately 2400 to approximately 3600N, and the magnetic flux density of the permanent electromagnet 163 when the permanent electromagnet 163 attracts the support portion 15a with the first attraction force is approximately 0.06 to approximately 0.09T. The surface pressure generated between the sliding surface 161d and the sliding surface 161e when the permanent electromagnet 163 sucks the support portion 15a with the second suction force is approximately 0.16 to approximately 0.24 MPa.

The permanent electromagnet 163 sucks the support portion 15a with the second suction force, and thereby the sliding surface 161d abuts against the sliding surface 161 e. At this time, the sliding surface 161d and the sliding surface 161e are not in close contact with each other, and the oil film formed between the sliding surface 161d and the sliding surface 161e is not eliminated.

Since the sliding surface 161d abuts against the sliding surface 161e, the support portion 15a does not tilt with respect to the column 15c when the support portion 15a moves up and down. In terms of the restriction of the arrangement position, the permanent electromagnet 163 and the measurement unit 164 are arranged on the opposite side with respect to the movement mechanism 161, but since the support unit 15a is not inclined in the present embodiment, the measurement unit 164 can stabilize the measurement result of the measurement unit 164 and accurately move the support unit 15a up and down even at a position away from the permanent electromagnet 163.

Here, the reason why the second suction force is desired to be approximately 20% to approximately 30% of the first suction force will be described. Tables 1 and 2 show the torque of the rotary drive unit 161f (here, the motor) when the magnetization force of the permanent electromagnet 163 is changed. Tables 1 and 2 show the results obtained by experiments using different motors. Tables 1 and 2 are obtained by driving the rotary drive unit 161f to rotate the pinion 161b and move the support portion 15a in the height direction, and measuring the torque of the rotary drive unit 161f at that time, and the value of each cell is the torque (N · m).

The attraction force is proportional to the magnetic flux density of permanent electromagnet 163, that is, the voltage applied to permanent electromagnet 163. The attraction force in tables 1 and 2 is obtained based on the ratio of the voltage applied to permanent electromagnet 163 to the voltage applied to permanent electromagnet 163 when the magnetic flux density of permanent electromagnet 163 is maximum. Note that, the adsorption force 0% indicates a demagnetized state.

[ Table 1]

[ Table 2]

As shown in tables 1 and 2, the torque of the rotation driving unit 161f in the demagnetized state is almost unchanged from the torque of the rotation driving unit 161f in the cases where the attracting forces are 18.5% and 24%. In other words, if the second suction force is approximately 24% or less of the first suction force, the oil film formed between the sliding surface 161d and the sliding surface 161e is not excluded, and no friction is generated between the sliding surface 161d and the sliding surface 161 e.

On the other hand, the torque of the rotation driving unit 161f at the attraction force of 39% is about several times the torque of the rotation driving unit 161f in the demagnetized state, and is largely different from the torque of the rotation driving unit 161f in the demagnetized state. From this, it is found that when the suction force is 39%, the oil film formed between the sliding surface 161d and the sliding surface 161e is removed, and friction is generated between the sliding surface 161d and the sliding surface 161 e.

From the above, from the viewpoint of preventing friction from occurring between the sliding surface 161d and the sliding surface 161e, it is not appropriate to set the second suction force to be substantially 39% of the first suction force, and it is desirable to set the second suction force to be substantially 30% or less of the first suction force.

However, when the second suction force is smaller than approximately 20% of the first suction force, the measurement result measured by the measurement unit 164 changes when the state where the support unit 15a is sucked with the second suction force changes to the state where the support unit 15a is sucked with the first suction force. From this, it is understood that when the second suction force is smaller than approximately 20% of the first suction force, the sliding surface 161d and the sliding surface 161e do not abut, and the support portion 15a is inclined with respect to the post 15c when the support portion 15a moves up and down. From the above, it is desirable that the second suction force is set to be approximately 20% to approximately 30% of the first suction force.

Next, the light irradiation unit 30 will be explained. Fig. 6 is a main part perspective view showing an outline of the light irradiation section 30 a. The light irradiation section 30a mainly includes a DMD31a, an objective lens 32a, a light source section 33a, an AF processing section 34a, a cylindrical section 35a, a flange 36a, mounting sections 37a, 38a, and a driving section 39 a. The light irradiation sections 30b to 30g include DMDs 31b to 31g, objective lenses 32b to 32g, light source sections 33b to 33g, AF processing sections 34b to 34g, tubular sections 35b to 35g, flanges 36b to 36g, attachment sections 37b to 37g, 38b to 38g, and driving sections 39b to 39g, respectively. The light irradiation portions 30b to 30g have the same configuration as the light irradiation portion 30a, and therefore, description thereof is omitted.

The DMD31a is a Digital Mirror Device (DMD) and can irradiate a planar laser beam. The DMD31a has a plurality of movable micromirrors (not shown), and irradiates light corresponding to one pixel from one micromirror. The micro mirrors are approximately 10 μm in size and arranged in two dimensions. Light is irradiated from a light source 33a (described in detail later) to the DMD31a, and the light is reflected by each micromirror. The micromirror is rotatable about an axis substantially parallel to its diagonal line, and can be switched between on (reflecting light toward the mask M) and off (not reflecting light toward the mask M). DMD31a is already known, and therefore, detailed description is omitted.

The objective lens 32a forms the laser light reflected by each micromirror of the DMD31a on the surface of the mask M. At the time of drawing, light is irradiated from the light irradiation section 30a to the light irradiation section 30g, respectively, and the light forms an image on the mask M, thereby drawing a pattern on the mask M.

The light source 33a mainly includes a light source 331, a lens 332, a fly-eye lens 333, lenses 334 and 335, and a mirror 336. The light source 331 is, for example, a laser diode, and light emitted from the light source 331 is guided to the lens 332 via an optical fiber or the like.

Light is directed from lens 332 to fly-eye lens 333. The fly-eye lens 333 is formed by arranging a plurality of lenses (not shown) in a two-dimensional shape, and a plurality of point light sources are formed in the fly-eye lens 333. The light having passed through fly-eye lens 333 is made into parallel light by lenses 334 and 335 (for example, condenser lenses), and is reflected by mirror 336 toward DMD31 a.

The AF processing unit 34a focuses light emitted to the mask M on the mask M, and mainly includes an AF light source 341, a collimator lens 342, an AF cylindrical lens 343, pentagonal prisms 344 and 345, a lens 346, and AF sensors 347 and 348. The light emitted from the AF light source 341 is collimated by the collimator lens 342, and is linear by the AF cylindrical lens 343, and is reflected by the pentagonal prism 344 to form an image on the surface of the mask M. The light reflected by the mask M is reflected by the pentagonal prism 345, condensed by the lens 346, and incident on the AF sensors 347 and 348. The pentagonal prisms 344, 345 bend the light at a bend angle of approximately 97 degrees. Although a mirror may be used instead of the pentagonal prisms 344 and 345, the pentagonal prisms are preferably used because the angle of the mirror is deviated to cause a focus to be blurred. The AF processing unit 34a performs autofocus processing for determining the in-focus position based on the results received by the AF sensors 347 and 348. Since such an optical lever type autofocus process is already known, a detailed description thereof will be omitted.

The light irradiation unit 30a has a cylindrical portion 35a having a substantially cylindrical shape in which an optical system (including the objective lens 32a) is provided. A flange 36a is provided at an upper end of the cylindrical portion 35 a. The flange 36a holds the lens 332, the fly-eye lens 333, and the lenses 334 and 335 on the upper side. Therefore, the center of gravity of the light irradiation section 30a is shifted leftward in fig. 6 from the optical axis ax.

Further, the cylindrical portion 35a is provided with attachment portions 37a and 38 a. The attachment portions 37a and 38a are used for attachment to the housing 15. The mounting portion 37a is provided near the flange 36a, and the mounting portion 38a is provided near the lower end of the cylindrical portion 35 a. The mounting portion 37a is formed with a hollow portion 372 having a diameter larger than the outer diameter of the mounting portion 38 a. This allows the cylindrical portion 35a to be pulled upward. In fig. 6, screw holes 371 and 381 (described in detail later) formed in the mounting portions 37a and 38a are not shown.

The mounting portion 37a (i.e., the light irradiation portion 30a) is moved in the vertical direction (z direction) by the driving portion 39 a. Fig. 7 is a side view schematically showing the driving portion 39 a. The driver 39a mainly includes a piezoelectric element 391 and a coupling portion 392.

The piezoelectric element 391 is a solid-state actuator (piezoelectric element) that generates displacement by application of a voltage. A portion (for example, a lower end) of the piezoelectric element 391 which does not displace is provided on the support portion 15a of the housing 15 via the mounting portion 395 (see fig. 11). When a voltage is applied to the piezoelectric element 391, the piezoelectric element 391 extends, and the upper end of the piezoelectric element 391 moves upward. The broken line in fig. 7 indicates a state where the piezoelectric element 391 contracts, and the solid line in fig. 7 indicates a state where the piezoelectric element 391 extends.

The connecting portion 392 is a substantially cylindrical member having a lower end screwed to the piezoelectric element 391. The connecting portion 392 moves up and down in accordance with expansion and contraction of the piezoelectric element 391.

A convex portion 393 having an arc-shaped tip end is provided at an upper end of the coupling portion 392. The tip of the convex portion 393 abuts against the lower side of the mounting portion 37a (see fig. 6). Therefore, the light irradiation section 30a moves in the + z direction when the piezoelectric element 391 extends, and the light irradiation section 30a moves in the-z direction when the piezoelectric element 391 contracts.

A plurality of grooves 394 are formed in the side surface of the coupling portion 392. The groove 394 is formed by cutting obliquely downward as it approaches the central axis. Therefore, even if the piezoelectric element 391 extends while being bent (see the two-dot chain line in fig. 7), the convex portion 393 can be moved only in the vertical direction without moving in the horizontal direction by deforming the coupling portion 392 at the portion of the groove 394.

Next, a mounting structure for mounting the light irradiation units 30a to 30g to the housing 15 will be described. In the mounting structure of the present embodiment, the guide member 70 is mounted on the bottom plate 151, the guide member 70A is mounted on the support plate 153, and the light irradiation portions 30A to 30g are mounted on the guide members 70 and 70A, whereby the light irradiation portions 30A to 30g are mounted on the housing 15. In other words, the guide members 70 and 70A are attached between the light irradiation section 30A and the frame body 15 (here, the support plate 153).

First, the guide members 70 and 70A will be explained. The guide members 70 and 70A are substantially thin plate-like members provided between the support portion 15a (the bottom plate 151 and the support plate 153) and the light irradiation portion 30.

Fig. 8 (a) is a diagram showing an outline of the guide member 70, and fig. 8 (B) is a diagram showing an outline of the guide member 70A. The guide member 70 is different in diameter from the guide member 70A.

The guide members 70, 70A are substantially thin plate-like and substantially disk-like in plan view. The guide members 70, 70A are made of metal having a thickness of approximately 0.5 to 1 mm. In the present embodiment, the guide member 70 is substantially 0.5mm, and the guide member 70A is substantially 1 mm. As the metal, stainless steel, phosphor bronze, or the like can be used, but it is desirable to use phosphor bronze of a more homogeneous quality. About 0.5 to 1mm in the present invention means that an error of about 0.5mm or less is included in about 0.5 to 1 mm.

Mounting holes 74, 74A are formed substantially at the centers of the guide members 70, 70A. Further, the guide members 70 and 70A have a plurality of holes 77 formed along the outer peripheries thereof, and a plurality of holes 78 formed along the mounting holes 74 and 74A.

A plurality of cutout holes 79A, 79B having a substantially circular arc shape are formed in the guide member 70, respectively, so that the guide member 70 is easily deformed. The slit holes 79A and 79B are arranged at equal intervals in the circumferential direction. The radius of the notch hole 79A is smaller than the radius of the notch hole 79B, and the notch hole 79B is disposed outside the notch hole 79A. Further, an end region 79Aa including an end of the notch hole 79A substantially coincides with a position in the circumferential direction of an end region 79Ba including an end of the notch hole 79B. The end regions 79Aa and 79Ba are present at both ends of the slit holes 79A and 79B, respectively.

A plurality of cutout holes 79C, 79D having a substantially circular arc shape are formed in the guide member 70A, respectively, so that the guide member 70A is easily deformed. The slit holes 79C and 79D are arranged at equal intervals in the circumferential direction. The radius of the notch hole 79C is smaller than the radius of the notch hole 79D, and the notch hole 79D is disposed outside the notch hole 79C. In addition, the end region 79Ca including the end of the slit hole 79C substantially coincides with the position in the circumferential direction of the end region 79Da including the end of the slit hole 79D. The end regions 79Ca and 79Da are present at both ends of the slit holes 79C and 79D, respectively.

In the present embodiment, the number of the slit holes 79A, 79B, 79C, and 79D is 4, but the positions and the number of the slit holes 79A, 79B, 79C, and 79D are not limited to these.

The end region 79Aa and the end region 79Ba are located at substantially the same position in the circumferential direction, and the overlapping positions are arranged uniformly (for example, at substantially 45 degrees) in the circumferential direction. The end region 79Ca and the end region 79Da are located at substantially the same position in the circumferential direction, and the overlapping positions are arranged uniformly (for example, at substantially 45 degrees) in the circumferential direction. Therefore, if a line extending radially in the radial direction is drawn from the center point of the guide member 70, 70A, the line necessarily passes through at least one of the slit holes 79A to 79D. Therefore, the deformation amount of the guide members 70, 70A is substantially constant regardless of the circumferential position. By disposing the slit holes 79A to 79D in this manner, even if a thick thin plate having a thickness of about 1mm is used for the guide members 70 and 70A, the guide members 70 and 70A expand and contract in accordance with the vertical movement of the cylindrical portion 35a having a thickness of about 30 μm.

Fig. 9 (a) shows a positional relationship between the base plate 151 and the guide member 70 when the guide member 70 is mounted on the base plate 151, and fig. 9 (B) shows a positional relationship between the support plate 153 and the guide member 70A when the support plate 153 is provided with the guide member 70A.

7 guide members 70 are provided on the bottom plate 151 so as to cover the circular holes 155a to 155 g. The support plate 153 is provided with 7 guide members 70A so as to cover the circular holes 156a to 156 g. The mounting holes 74, 74A and the circular holes 155a to 155g, 156a to 156g are arranged substantially concentrically.

The guide member 70 and the circular holes 155a to 155g are uniformly arranged at the central portion of the base plate 151, and the guide member 70A and the circular holes 156a to 156g are uniformly arranged at the central portion of the support plate 153. The intervals between the adjacent circular holes 155a to 155g (i.e., the guide members 70) and the interval W2 between the adjacent circular holes 156a to 156g (i.e., the guide members 70A) are substantially the same as the intervals between the light irradiation portions 30A to 30 g.

The cylindrical portion 35 of the light irradiation portion 30A is provided on the guide members 70 and 70A provided on the circular holes 155a and 156 a. The light irradiation portions 30b are provided on the guide members 70 and 70A provided in the circular holes 155b and 156 b. Similarly, light irradiation portions 30c to 30g are provided on the guide members 70 and 70A provided in the circular holes 155c to 155g and 156c to 156g, respectively.

The circular hole 155a and the circular hole 156a are formed so as to overlap each other in a position in a plan view. Similarly, the circular holes 155b to 155g and the circular holes 156b to 156g are formed so as to overlap each other in a position in a plan view.

Next, the mounting of the light irradiation unit 30a will be described. Fig. 10 is an exploded perspective view of a mounting structure for mounting the light irradiation unit 30a to the support plate 153. The mounting structure for mounting the light irradiation units 30b to 30g to the bottom plate 151 and the mounting structure for mounting the light irradiation units 30b to 30g to the support plate 153 are the same as the mounting structure for mounting the light irradiation unit 30a to the bottom plate 151, and therefore, the description thereof is omitted.

The guide member 70A is provided on the support plate 153 so as to cover the circular hole 156 a. The guide member 70A is fixed to the support plate 153 by inserting the screw 85 into the hole 77 and screwing the screw 85 into the screw hole 156h formed in the support plate 153.

The light irradiation section 30A (i.e., the cylindrical section 35a) is provided to the guide member 70A via the mounting section 37 a. The guide member 70A is fixed to the mounting portion 37a by inserting the screw 86 into the hole 78 and screwing the screw 86 into the screw hole 371. Thus, the light irradiation unit 30A is inserted into the mounting hole 74A so that the optical axis thereof substantially coincides with the center of the mounting hole 74A, and is fixed to the guide member 70A.

Fig. 11 is a diagram schematically showing a state in which the light irradiation unit 30a is attached to the housing 15 (here, the support unit 15 a). Fig. 11 shows a state of being cut at a plane passing through the centers of the mounting hole 74 and the holes 75 and 76. In fig. 11, a part of the components is shown in cross section. In fig. 11, fastening members such as screws 85 and 86 and holes provided for the fastening members are not shown.

The cylindrical portion 35a is inserted into the mounting holes 74, 74A of the guide members 70, 70A. The guide member 70 and the mounting portion 38a are fixed in a state where the mounting portion 38a is positioned above the guide member 70 and a portion of the cylindrical portion 35a below the mounting portion 38a is positioned below the guide member 70. The guide member 70A and the mounting portion 37a are fixed in a state where the mounting portion 37a is positioned above the guide member 70A and a portion of the cylindrical portion 35a below the mounting portion 37a is positioned below the guide member 70A.

Note that, when the guide members 70 and 70A are attached to the housing 15 and the light irradiation unit 30, a pressure ring may be used. By using the pressing ring, deformation of the guide members 70, 70A can be prevented.

Since the center of the circular hole 155a and the center of the circular hole 156a substantially coincide with each other in a plan view, the light irradiation unit 30a is attached to the support unit 15a such that the optical axis ax is substantially vertical.

The holes 79A coincide with the positions in the horizontal direction of the AF light source 341 and the AF sensors 347, 348, respectively, so that light irradiated downward from the AF light source 341 and reflected light at the mask M can pass therethrough. In other words, the position of the hole 79A overlaps with the positions of the AF light source 341 and the AF sensors 347 and 348 in a plan view.

The driving portion 39a is provided on the supporting portion 15a via the mounting portion 395, and pushes up the mounting portion 37a to move the mounting portion 37a in the vertical direction. The center of gravity G of the light irradiation section 30a is located in the vicinity of the position where the driving section 39a lifts up the mounting section 37 a. Therefore, the driving unit 39a lifts up the light irradiation unit 30a in the vicinity of the center of gravity G. This stabilizes the vertical movement of the light irradiation unit 30 a.

Fig. 12a shows a state in which the light irradiation unit 30a is not moved (stroke center), fig. 12B shows a state in which the light irradiation unit 30a is moved downward (stroke lower end), and fig. 12C shows a state in which the light irradiation unit 30a is moved upward (stroke upper end).

Since the guide members 70 and 70A are fixed to the cylindrical portion 35a via the mounting portions 37a and 38a (not shown in fig. 12), the guide members 70 and 70A deform as the driving portion 39a of the cylindrical portion 35a moves up and down.

The amount of movement of the cylindrical portion 35a by the driving portion 39a is approximately 40 μm (± approximately 20 μm). Since the guide members 70, 70A are made of thin metal, the guide members 70, 70A expand and contract (elastically deform) in accordance with the vertical movement of the cylindrical portion 35a of approximately 40 μm. Since the guide members 70 and 70A have a circular shape in plan view, the amount of deformation of the guide members 70 and 70A is substantially constant regardless of the position, and the cylindrical portion 35a does not move in the xy direction.

Fig. 13 is a block diagram showing an electrical configuration of the exposure apparatus 1. The exposure apparatus 1 includes a cpu (central Processing unit)201, a ram (random Access memory)202, a rom (read Only memory)203, an input/output interface (I/F)204, a communication interface (I/F)205, and a media interface (I/F)206, which are connected to the light irradiation unit 30, the position measurement units 41 and 42, the laser interferometers 51 and 52, the measurement unit 61, the driving units 81 and 82, the rotation driving unit 161F, the permanent electromagnet 163, the measurement unit 164, the piezoelectric element 391, and the like.

The CPU201 operates based on programs stored in the RAM202 and the ROM203, and controls each unit. Signals are input to the CPU201 from the position measuring units 41 and 42, the laser interferometers 51 and 52, the measuring unit 61, the measuring unit 164, and the like. The signal output from the CPU201 is output to the light irradiator 30, the drivers 81 and 82, the rotation driver 161f, the permanent electromagnet 163, the piezoelectric element 391, and the like.

The RAM202 is a volatile memory. The ROM203 is a nonvolatile memory in which various control programs and the like are stored. The CPU201 operates based on programs stored in the RAM202 and the ROM203, and controls each unit. The ROM203 stores a startup program executed by the CPU201 at the time of startup of the exposure apparatus 1, a program dependent on hardware of the exposure apparatus 1, drawing data for drawing the mask M, and the like. The RAM202 stores programs executed by the CPU201, data used by the CPU201, and the like.

The CPU201 controls an input/output device 211 such as a keyboard and a mouse via an input/output interface 204. The communication interface 205 receives data from other devices via the network 212 and transmits the data to the CPU201, and transmits data generated by the CPU201 to other devices via the network 212.

The media interface 206 reads the program or data stored in the storage medium 213 and stores it in the RAM 202. The storage medium 213 is, for example, an IC card, an SD card, a DVD, or the like.

The programs for realizing the respective functions are read from the storage medium 213, installed in the exposure apparatus 1 via the RAM202, and executed by the CPU 201.

The CPU201 has a function of a control section 201a that controls each section of the exposure apparatus 1 based on an input signal. The control unit 201a is constructed by executing a predetermined program read by the CPU 201. The control unit 201a drives the rotation driving unit 161f to move the support unit 15a in the z direction. The control unit 201a supplies current to the coil of the electromagnet 163b to attract the supporting portion 15a with the first attracting force or the second attracting force. The processing performed by the control unit 201a will be described in detail later.

The configuration of the exposure apparatus 1 shown in fig. 13 has been described mainly in describing the features of the present embodiment, and for example, the configuration of a general information processing apparatus is not excluded. The components of the exposure apparatus 1 may be classified into more components according to the process content, and one component may execute the process of a plurality of components.

The operation of the exposure apparatus 1 configured as described above will be described. The following processing is mainly performed by the control unit 201 a.

Fig. 14 is a flowchart showing the flow of the height adjustment process of the exposure apparatus 1. The controller 201a sets the mask M on the mask holding unit 20 by using a loader (not shown) (step S10). Thereafter, the control unit 201a moves the mask holding unit 20 via the driving units 81 and 82 to adjust the position of the mask M (step S12). The processing in steps S10 and S12 is already known, and therefore, the description thereof is omitted.

Next, the control unit 201a moves the support portion 15a in the height direction, and moves the position of the support portion 15a in the height direction to the origin position (step S14). The origin position is a position determined from the height (stored in advance) of the mask holding unit 20 and the standard of the mask M to be set, and is a position where the focal point of the light irradiation unit 30 is focused on the mask M when these components are standard values. The position of the support portion 15a in the x direction in step S14 is the center position (x center).

Here, a process of the control unit 201a moving the support portion 15a in the height direction will be described. First, the control unit 201a supplies a current to the coil of the electromagnet 163 b. Since the current is adjusted by the adjustment dial 163c, the permanent magnet 163 attracts the support portion 15a with the second attracting force. Thereafter, the control unit 201a drives the rotation driving unit 161f to rotate the pinion gear 161b, thereby moving the rack 161a, i.e., the support portion 15a, in the height direction. At this time, the control unit 201a continuously obtains the measurement result measured by the measurement unit 164, and drives the rotation driving unit 161f until the measurement result measured by the measurement unit 164 becomes a target value.

Since the permanent magnet 163 attracts the support portion 15a with the second attracting force, the sliding surface 161d abuts against the sliding surface 161e, but the oil film formed between the sliding surface 161d and the sliding surface 161e is not excluded. Therefore, when the support portion 15a moves in the z direction, the sliding surface 161e slides along the sliding surface 161 d. In this way, when the support portion 15a moves in the z direction, the support portion 15a does not tilt with respect to the column 15c, and thus the measurement result measured by the measurement portion 164 is stable.

The steps (steps S10 to S14) are preparatory steps for adjusting the height of the light irradiation unit 30. Next, the control unit 201a measures the height of the mask M by the measuring units 61a and 61g while moving the mask holding unit 20 in the x direction by the driving units 81 and 82 (step S20). Then, the controller 201a calculates the amount of movement of the light irradiator 30 in the height direction (the amount of driving of the driver 39a and the amount of movement of the support 15a) based on the measurement result measured in step S20 (step S22). The process of step S22 will be described in detail below.

Fig. 15 shows an example of the measurement result in step S20. Here, the measurement result measured by the measurement unit 61a is exemplified, and the obtained value is a value for the light irradiation unit 30 a. The control unit 201a calculates the center position (thickness center) of the lowest value (BOTTOM) and the highest value (PEAK) of the measurement result using equation (1).

[ equation 1]

(PEAK + BOTTOM)/2 ═ thickness center (1)

Further, the control section 201a calculates the difference between the measurement result at the center position (x center) in the x direction and the thickness center as PZT-OFS. The PZT-OFS is a driving amount of the piezoelectric element 391 when the position of the support portion 15a in the x direction is at the x center and the piezoelectric element 391 is at the stroke center, and the height of the support portion 15a is adjusted so that the focal position of the light irradiator 30 becomes the thickness center. The PZT-OFS value is positive when the measurement result is larger than the thickness center, and the PZT-OFS value is negative when the measurement result is smaller than the thickness center.

In the present embodiment, although the support 15a is moved to the x center in step S14 and PZT-OFS is obtained based on the measurement result at the x center in step S22, it is also possible to move the support 15a to the-x end in step S14 and obtain PZT-OFS based on the measurement result at the-x end in step S22, for example. In other words, the x center in steps S14 and S22 is an example, and the position in the x direction is not limited to the x center.

The controller 201a calculates a value obtained by adding a value (here, 20 μm) for disposing the piezoelectric element 391 at the stroke center to the PZT-OFS as the amount of movement in the vertical direction of the light irradiator 30. The value of 20 μm varies depending on the type of the piezoelectric element 391.

Since the measurement is performed using the measurement units 61a and 61g in step S20, the amount of movement in the height direction of the light irradiation units 30a and 30g is determined from the measurement results. In step S22, the control unit 201a calculates the amount of movement (the thickness center and the PZT — OFS) of the light irradiation units 30b to 30f in the height direction by interpolation based on the amount of movement of the light irradiation units 30a and 30g in the height direction, which is directly obtained from the measurement result.

The explanation returns to fig. 14. The controller 201a drives the piezoelectric elements 391 provided in the light irradiators 30a to 30g by the amount corresponding to the value calculated in step S22 (the value obtained by adding 20 μm to PZT — OFS) from the lower end position (step S24).

Next, the control unit 201a drives the rotary drive unit 161f to move the support unit 15a in the height direction while checking whether or not the light irradiation units 30a to 30g irradiate the mask M with light having its focus on the mask M via the AF processing unit 34 (step S26).

In step S14, since the support portion 15a is attracted by the second attracting force, the permanent magnet 163 continues to attract the support portion 15a by the second attracting force. Therefore, in step S26, the sliding surface 161d also abuts against the sliding surface 161e, and the sliding surface 161e also slides along the sliding surface 161 d.

The AF processing unit 34 continuously determines how much the in-focus position needs to be moved, and the control unit 201a continuously obtains the result. The control unit 201a drives the rotation driving unit 161f while continuously obtaining the measurement result measured by the measurement unit 164, and moves the support unit 15a in the height direction by the movement distance obtained by the AF processing unit 34.

In step S24, since the piezoelectric element 391 is driven from the lower end position by an amount corresponding to the value obtained by adding 20 μm to the PZT-OFS, the light irradiated from the light irradiation section 30 is focused on the thickness center as a result of moving the support section 15a in step S26 when the piezoelectric element 391 is at the stroke center. Thus, even if the height of the mask M changes, the light irradiator 30 can be always focused on the mask M by the movement of the piezoelectric element 391.

After that, the control unit 201a determines whether or not the light irradiated from the light irradiation unit 30 via the AF processing unit 34 is focused on the mask M (step S28). In steps S24 and S26, since the light irradiation section 30 is moved, in step S28, the light irradiated from the light irradiation section 30 is usually focused on the mask M. If the light irradiator 30 is not located at the position determined to be in focus (no in step S28), the controller 201a returns the process to step S26.

When the light irradiation unit 30 is located at the position determined to be in focus (yes in step S28), the control unit 201a causes the current to flow through the coil of the electromagnet 163b, causes the permanent electromagnet 163 to attract the support unit 15a with the first attraction force, and causes the sliding surface 161d to come into close contact with the sliding surface 161e (step S30). As a result, friction is generated between the sliding surface 161d and the sliding surface 161e, and the support portion 15a is fixed to the post 15c by a frictional force.

In step S14, permanent electromagnet 163 sucks support portion 15a with the second suction force, and therefore permanent electromagnet 163 continues to suck support portion 15a with the second suction force until step S30. When the value of the adjustment dial 163c is shifted to "10" in this state, the current value flowing through the coil of the electromagnet 163b increases, and the attraction force of the permanent electromagnet 163 changes from the second attraction force to the first attraction force. In terms of the properties of the permanent electromagnet 163, the adsorption force can be increased from the second adsorption force to the first adsorption force (the adsorption force cannot be decreased from the first adsorption force to the second adsorption force).

In the present embodiment, since the sliding surface 161d abuts against the sliding surface 161e and the sliding surface 161d slides along the sliding surface 161e when the support portion 15a moves, the sliding surface 161d, that is, the support portion 15a does not tilt even if the sliding surface 161d is brought into close contact with the sliding surface 161e by the attraction force of the permanent electromagnet 163. Therefore, the measurement result measured by the measurement portion 164 does not change regardless of whether the support portion 15a moves or does not move.

For example, as shown in fig. 16B and C, when the support portion 15a is moved in the height direction (see the hollow arrows in fig. 16B and C) in a state where the support portion 15a is inclined with respect to the column 15C (in a state where the sliding surface 161d is inclined with respect to the sliding surface 161e), the support portion 15a rotates (see the thick arrows in fig. 16B and C) when the sliding surface 161d is brought into close contact with the sliding surface 161e, and the measurement result measured by the measurement portion 164 changes. Even if the inclination of the sliding surface 161d at this time is a slight angle of 1 degree or less, or the gap between the sliding surface 161d and the sliding surface 161e is as small as about several μm, the supporting portion 15a is large, and the measuring portion 164 has to be provided on the surface opposite to the surface on which the permanent electromagnet 163 is provided, and therefore, an error that cannot be ignored occurs in the measurement result measured by the measuring portion 164. On the other hand, as shown in fig. 16 a (this embodiment), when the support 15a is moved in the height direction while the sliding surface 161d is brought into contact with the sliding surface 161e, the support 15a does not tilt when the sliding surface 161d is brought into close contact with the sliding surface 161e, and therefore the measurement result measured by the measurement unit 164 does not change regardless of whether the support 15a is moved or not. In this way, in the present embodiment, an error due to the inclination of the support portion 15a can be eliminated.

When the height of the support 15a is fixed (step S30), the controller 201a creates an AF map indicating how much the mask holding unit 20 needs to be moved to focus the light irradiated from the light irradiators 30a to 30g on the mask M using the AF processors 34a to 34g while moving the mask holding unit 20 in the x direction and the y direction by the drivers 81 and 82, respectively, and confirms whether or not the driving amount of the piezoelectric element 391 does not exceed ± 20 μ M (step S32). The preparation of the AF map is already known, and therefore, the description is omitted.

If the driving amount of the piezoelectric element 391 exceeds ± 20 μm, the controller 201a moves the support portion 15a in a direction in which the driving amount of the piezoelectric element 391 exceeds ± 20 μm.

This ends the processing shown in fig. 14. The processing shown in fig. 14 is an example, and the order of the processing and the processing content are not limited to this.

After that, a drawing process not shown is performed. The control unit 201a moves the mask holding unit 20 in the x direction and the y direction based on the measurement results of the position measuring units 41 and 42. The control unit 201a performs the drawing process by irradiating light from the light irradiation unit 30 when the mask M passes under the light irradiation unit 30 while moving the mask holding unit 20. Since the drawing process is performed after several hours have elapsed since the mask M was placed on the mask holding unit 20, the control unit 201a has a sufficient margin time to perform the process of step S32.

According to the present embodiment, since the support portion 15a provided with the light irradiator 30 is moved up and down by using the moving mechanism 161 including the rack 161a and the pinion 161b, a follow-up error does not occur unlike the case of using a ball screw. Therefore, the height of the light irradiation section can be accurately adjusted.

Further, according to the present embodiment, the permanent magnet 163 is used to attract the support portion 15a with the first attraction force, and the sliding surface 161d and the sliding surface 161e are brought into close contact with each other to remove the oil film between the sliding surface 161d and the sliding surface 161e, whereby the support portion 15a can be held by the frictional force generated between the sliding surface 161d and the sliding surface 161 e. Further, by sucking the support portion 15a with the second suction force (second suction force < first suction force) using the permanent electromagnet 163 and moving the support portion 15a up and down in a state where the sliding surface 161d is brought into contact with the sliding surface 161e, the measurement result measured by the measurement portion 164 does not change regardless of whether the support portion 15a is moving or not moving, and an error due to the inclination of the support portion 15a can be eliminated.

Further, according to the present embodiment, since the permanent electromagnet 163 is used, the energization time is shortened, and deformation, expansion, and the like of the support portion 15a due to heat are not generated. Therefore, the height of the support portion 15a, i.e., the light irradiation portion, can be accurately adjusted.

While the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to the embodiments, and design changes and the like are included within a range not departing from the gist of the present invention. Those skilled in the art can appropriately change, add, or convert each element of the embodiment.

In the present invention, "substantially" is a concept as follows: the term "identical" includes not only the case where they are strictly identical but also errors and variations to the extent that they do not lose their identity. For example, substantially horizontal is the following concept: the error is not limited to the strictly horizontal case, but includes, for example, an error of about several degrees. For example, when only parallel or orthogonal is described, the term includes not only the case where the two are strictly parallel or orthogonal but also the case where the two are approximately parallel or approximately orthogonal. In the present invention, "vicinity" refers to a region including a certain range (which can be arbitrarily specified) in the vicinity of a reference position. For example, the vicinity of a is a concept as follows: the area indicating a certain range in the vicinity of a may include a or may not include a.

Description of reference numerals:

1: exposure device

11: platform

11 a: upper surface of

12: plate-shaped part

12 a: upper surface of

13. 14: guide rail

15: frame body

15 a: support part

15 c: column

20: mask holding part

20 a: upper surface of

21. 22, 23: bar-shaped reflector

30(30a to 30 g): light irradiation section

31(31a～31g)：DMD

32(32a to 32 g): objective lens

33(33a to 33 g): light source unit

34(34a to 34 g): AF processing part

35(35a to 35 g): cylindrical part

36(36a to 36 g): flange

37(37a to 37g) and 38(38a to 38 g): mounting part

39(39a to 39 g): driving part

40: measuring part

41. 42: position measuring part

41a, 42 a: scale with a measuring device

41b, 42 b: detection head

50. 51(51a, 51b, 51c), 52(52a, 52 g): laser interferometer

55a, 55b, 55c, 56a, 56 g: reflecting mirror

60: reading unit

61(61a, 61d, 61 g): measuring part

70. 70A: guide member

74. 74A: mounting hole

75. 76, 77, 78: hole(s)

79A, 79B, 79C, 79D: incision hole

79Aa, 79Ba, 79Ca, 79 Da: end region

81. 82: driving part

85. 86: screw with a thread

151: base plate

152. 154: side plate

152a to 152i, 154a to 154 i: hole(s)

153: support plate

155a to 155g, 156a to 156 g: round hole

156 h: threaded hole

157a to 157 g: round hole

158: convex part

159: partition wall

160: elastic member

161: moving mechanism

161 a: rack bar

161 b: pinion gear

161 c: convex part

161d, 161 e: sliding surface

161 f: rotary driving part

162: positioning member

162 a: concave part

163: permanent electromagnet

163 a: permanent magnet

163 b: electromagnet

163 c: adjustable dial

164: measuring part

164 a: scale with a measuring device

164 b: detection head

201：CPU

201 a: control unit

202：RAM

203：ROM

204: input/output interface

205: communication interface

206: media interface

211: input/output device

212: network

213: storage medium

331: light source

332: lens and lens assembly

333: fly-eye lens

334. 335: lens and lens assembly

336: reflecting mirror

341: light source for AF

342: collimating lens

343: cylindrical lens for AF

344. 345 parts by weight: pentagonal prism

346: lens and lens assembly

347. 348: sensor with a sensor element

371: threaded hole

372: hollow part

381: threaded hole

391: piezoelectric element

392: connecting part

393: convex part

394: trough

395: an installation part.

Claims (7)

1. An exposure apparatus, characterized in that,

the exposure device is provided with:

a substrate holding section for placing a substrate;

a frame body having a substantially rod-shaped support portion formed of a magnetic material and provided so that a longitudinal direction thereof is substantially horizontal, and a rod-shaped column provided so that a longitudinal direction thereof is substantially vertical at both ends of the support portion, the support portion having a support portion side sliding surface formed thereon, the column having a column side sliding surface formed thereon at a position facing the support portion side sliding surface;

a moving mechanism that moves the support portion in a vertical direction, and that has a rack provided on the support portion, a pinion rotatably provided on the column and meshed with the rack, and a rotation driving portion that rotates the pinion;

an optical device that is provided on the support portion and irradiates the substrate with light;

a permanent electromagnet provided to the column and having a permanent magnet and an electromagnet; and

a control unit that drives the rotation driving unit to move the support unit and applies a current to a coil of the electromagnet to cause the permanent magnet to attract the support unit,

the permanent electromagnet attracts the support portion to bring the support portion side sliding surface into close contact with the column side sliding surface, and the support portion is fixed to the column by a frictional force between the support portion side sliding surface and the column side sliding surface.

2. The exposure apparatus according to claim 1,

the exposure apparatus includes a measurement unit having a scale provided substantially in a vertical direction and a head for reading a value of the scale and outputting position information,

when the support portion moves, the permanent electromagnet attracts the support portion with a second attracting force that is weaker than a first attracting force that is a attracting force when the moving mechanism does not move the support portion, and the measuring portion continuously measures the height of the support portion, and the support portion-side sliding surface slides along the column-side sliding surface.

3. The exposure apparatus according to claim 2,

the second adsorption force is approximately 20% to approximately 30% of the first adsorption force.

4. The exposure apparatus according to any one of claims 1 to 3,

the exposure device is provided with:

a substantially thin plate-shaped guide member provided between the support portion and the optical device; and

a drive unit provided in the housing and moving the optical device in a vertical direction,

the support portion has a plate-like portion arranged substantially horizontally,

a circular hole penetrating in a substantially vertical direction is formed in the plate-like portion,

the guide member is substantially disk-shaped in plan view and is provided on the plate-shaped portion so as to cover the circular hole,

a mounting hole is formed substantially at the center of the guide member,

the mounting hole and the circular hole are arranged in a substantially concentric circle shape,

the optical device is inserted into the mounting hole so that an optical axis thereof substantially coincides with a center of the mounting hole, and is fixed to the guide member.

5. The exposure apparatus according to claim 4,

the exposure device is provided with:

a moving unit that moves the substrate holding unit in a scanning direction; and

a measuring unit provided on the support unit and measuring a distance to the substrate,

the control unit measures the distance to the substrate by the measuring unit while moving the substrate holding unit in the scanning direction by the moving unit, obtains a median value from a maximum value and a minimum value of the distance to the substrate, and obtains the driving amount of the driving unit based on the median value.

6. The exposure apparatus according to any one of claims 1 to 5,

the optical apparatus has an AF processing part having: a light source for AF that irradiates downward light; and an AF sensor for incidence of the reflected light,

the control unit moves the support unit while operating the AF processing unit, and causes the support unit side sliding surface and the column side sliding surface to be in close contact with each other when the optical device is located at a position determined to be in focus.

7. A height adjusting method is characterized in that the height of a supporting part is adjusted by using the following device,

the device has:

a substrate holding section for placing a substrate;

a frame body having a substantially rod-shaped support portion formed of a magnetic material and provided so that a longitudinal direction thereof is substantially horizontal, and a rod-shaped column provided so that a longitudinal direction thereof is substantially vertical at both ends of the support portion, the support portion having a support portion side sliding surface, the column having a column side sliding surface at a position facing the support portion side sliding surface;

a moving mechanism that moves the support portion in a vertical direction and that has a rack provided substantially in the vertical direction on the support portion, a pinion rotatably provided on the column and meshed with the rack, and a rotation driving portion that rotates the pinion;

a measuring unit provided to the support unit;

an optical device that is provided on the support portion and irradiates the substrate with light; and

a permanent electromagnet provided to the column and having a permanent magnet and an electromagnet,

the height adjusting method comprises the following steps:

passing a current through a coil of the electromagnet to cause the permanent electromagnet to attract the support portion with a second attracting force, thereby bringing the support portion side sliding surface into contact with the column side sliding surface;

driving the rotation driving unit to rotate the pinion gear while measuring the height of the support unit by the measuring unit, thereby moving the support unit in a height direction; and

the current is passed through the coil, so that the permanent electromagnet attracts the support portion with a first attracting force stronger than the second attracting force, and the support portion is fixed to the post by bringing the support portion-side sliding surface into close contact with the post-side sliding surface.

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