JP2009218389A - Gas pressure control type slightly-inclining device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To slightly incline an upper table against a lower table under control of a gas pressure. <P>SOLUTION: A gas pressure control type slightly-inclining device 10 is composed of: a main box body 12; a piston pedestal 20 guided by the main box body 12; the lower table 30 fixed to the upper part of the piston pedestal 20; the upper table 40 arranged above the lower table 30; an inclination supporting portion 50 and an inclination driving portion 70 arranged between the lower table 30 and the upper table 40; a gas pressure control valve 34 for supplying a gap controlling gas to the inclination driving portion 70; and a control portion 28. The inclination driving portion 70 includes: an objective pad, which has a gas blowing-out portion on an objective upper surface facing a rear surface of the upper table; a window through which the gas flows; and a plurality of flat plate moving members arranged arraying in parallel between a pad rear surface on the opposite side to the objective upper surface of the objective pad and the upper surface of the lower table. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a gas pressure control type micro tilting device, and more particularly to a gas pressure control type micro tilting device that tilts an upper table with respect to a lower table under the control of gas pressure.

  A moving mechanism using a gas actuator is less contaminated than other mechanisms, does not generate electromagnetic noise, and is less affected by temperature changes, vibration, and noise. Thus, it has been proposed to configure a micro-movement mechanism with good responsiveness using a gas actuator, such as a use of a positioning actuator such as a semiconductor device.

  For example, Patent Document 1 focuses on the high spring constant of the gas bearing mechanism, changes the gap of the gas bearing by controlling the gas pressure supplied thereto, and uses this change in the gap for minute movement of the object. A configuration for realizing a minute movement mechanism with good responsiveness is shown. Here, there is a guide portion that guides the mover to which an appropriate pressing force is applied in the moving direction, and from an opening provided in a gas receiving wall that is a bottom surface of the guide portion, toward the gas receiving surface of the mover. A gas having a controlled gas pressure is supplied, the mover rises from the gas receiving wall, forms a gap while balancing with the pressing force, and the mover moves slightly by controlling the amount of the gap by the supply gas pressure. Is done. In addition, it is also stated that by arranging a plurality of movers in the axial direction and supplying a controlled gas pressure to the gaps between adjacent movers, the range of minute movement can be expanded according to the number of gaps. It has been.

  In this way, the mover can be accurately moved in a non-contact manner using the gas pressure. At this time, the gas pressure is also supplied to the moving object to accurately move the object in a non-contact manner. It has also been proposed to move well.

JP 2005-268293 A

  By developing the configuration disclosed in Patent Document 1, arranging a plurality of thin movers in the axial direction, and supplying a controlled gas pressure to the gap between adjacent movers, A gas pressure micro-movement mechanism that is small as a whole and has a wide movement range of micro movement can be configured.

  On the other hand, there is a demand for tilting a table or the like by a minute angle in order to hold an object on a table, a platform, or the like precisely and horizontally. Such tilt control can be realized by moving a small amount of one end of the table relative to the other end with a general actuator. Even in such a case, gas pressure control with low responsiveness is desired, since there is little contamination, no electromagnetic noise is generated, and there is little influence, vibration, and noise due to temperature change.

  An object of the present invention is to provide a gas pressure control type micro-tilt device which causes a micro-movement and a micro-tilt of the upper table with respect to the lower table under the control of the gas pressure.

  The gas pressure control type micro tilting device according to the present invention includes a lower table, an upper table arranged above the lower table, and a plurality of gas pressure control units arranged at a plurality of arrangement positions between the lower table and the upper table. And a plurality of tilt driving units that cause the upper table to move minutely independently in the vertical axis direction at each arrangement position under the control of the lower table, and causes the upper table to slightly tilt together with the minute movement with respect to the lower table. It is characterized by that.

  Further, the gas pressure control type micro tilting device according to the present invention has one end attached to the lower table, the other end attached to the upper table, and around each of two axes parallel to the plane direction of the lower table and orthogonal to each other. An inclined support portion having a degree of freedom of two-axis rotation, and a gas disposed between the lower table and the upper table at a plurality of arrangement positions spaced a predetermined distance from the inclined support portion in the plane of the lower table. Under the control of pressure, the upper table is slightly moved in the vertical axis direction at each placement position independently at each placement position, and the upper table is slightly moved and inclined slightly with respect to the lower table using the inclined support portion as a fulcrum. And a drive unit.

  Further, in the gas pressure control type micro tilting device according to the present invention, the tilt driving unit has an objective pad having a gas blowing part on the top surface of the objective facing the back surface of the upper table, and a through window through which gas can flow. A plurality of flat plate movers arranged in parallel between the back surface of the object pad opposite to the top surface of the objective pad and the top surface of the lower table, and a telescopic wall that can be expanded and contracted in the alignment axis direction of the plurality of flat plate movers. An airtight structure is formed between the table and the lower table, and a plurality of flat plate movers are accommodated so as to be movable along the alignment axis direction in which they are aligned, a gas blowing part of the objective pad, A through-hole of a flat plate mover, a pad side gap that is a gap between the most advanced flat plate mover facing the pad back surface and the pad back surface among a plurality of flat plate movers, and a gap between adjacent flat plate movers Each possible A gap for supplying a gap control gas to the gap between the child and the bottom-side gap that is the gap between the rearmost-side flat plate-moving element facing the bottom surface of the lower table and the bottom surface of the casing among the plurality of flat plate-shaped moving elements Control gas supply means, controlling the gas pressure of the gap control gas, and adjusting the gap between the gaps while balancing with the pressing force from the upper table, and the vertical direction of the upper table relative to the lower table It is preferable to move it slightly.

  Moreover, in the gas pressure control type minute tilting apparatus according to the present invention, it is preferable that the expansion / contraction wall portion of the hermetic accommodating portion is constituted by a bellows-type expansion / contraction member or a bellows-type expansion / contraction member.

  Moreover, the gas pressure control type micro inclination device according to the present invention preferably includes a vacuum suction means that is disposed outside the airtight housing portion and sucks the gas leaking from the airtight housing portion.

  Further, in the gas pressure control type minute tilting apparatus according to the present invention, the gap amount detecting means for detecting the gap amount between the objective upper surface of the objective pad and the back surface of the upper table, and the detection result of the gap amount detecting means. And a controller for controlling the gas pressure of the gap control gas.

  Moreover, the gas pressure control type minute tilting device according to the present invention preferably includes a gas pressure control actuator for moving and driving the lower table in the vertical axis direction.

  With at least one of the above-described configurations, the gas pressure control type minute tilting device has a plurality of tilt driving units arranged between the lower table and the upper table, and the upper table is placed on the lower table under the control of the gas pressure. In each arrangement position, they are moved minutely independently in the vertical axis direction, whereby the upper table is slightly moved and inclined with respect to the lower table under the control of the gas pressure.

  Further, with at least one of the above-described configurations, the gas pressure control type micro tilting device is tilted with a tilt support portion having a biaxial rotation degree of freedom attached to one end on the lower table and the other end on the upper table. The upper table is slightly moved with respect to the lower table by the inclined driving unit under the control of the gas pressure at each of a plurality of arrangement positions separated from the support unit by a predetermined distance. Thereby, the upper table is slightly inclined with respect to the lower table along with the minute movement.

  Further, in the gas pressure control type micro tilting device, a plurality of plate-like movable elements are arranged in parallel on the back surface of the objective pad opposite to the upper surface of the objective, and a gap control gas is supplied to the gaps between the movable elements. The upper table is slightly moved in the vertical axis direction with respect to the lower table while adjusting the interval between the gaps while balancing with the pressing force from the upper table. This configuration is described in Patent Document 1, and the gaps between the movable elements can be adjusted with high accuracy, and the objective pad can be moved minutely with high accuracy. Accordingly, the upper table can be finely inclined with high accuracy with respect to the lower table under the control of the gas pressure.

  Further, in the gas pressure control type minute tilting device, the stretchable wall portion of the hermetic housing portion is constituted by a bellows-like stretchable member or a bellows-like stretchable member, and thus a proven structure can be used.

  In addition, since the gas pressure control type minute tilting device has the vacuum suction means for sucking the gas leaking to the outside of the hermetic housing portion, the tilt driving unit can be operated even in a reduced pressure atmosphere or a vacuum atmosphere.

  Further, in the gas pressure control type minute tilting device, the gap amount between the object upper surface of the objective pad and the support object is detected, and the gas pressure of the gap control gas is controlled according to the detection result. As a result, the upper table can be finely inclined with high accuracy with respect to the lower table.

  Further, since the gas pressure control type minute tilting device includes the gas pressure control actuator that moves and drives the lower table in the vertical axis direction, the upper table can be slightly tilted at an arbitrary height position along the vertical axis.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following, a plurality of flat plate movers are arranged and arranged as an inclination driving unit for inclining the upper table with respect to the lower table, and the objective pad is moved by flowing a gap control gas through the gap between adjacent movers. Although the configuration will be described, other gas pressure control type actuators may be used. For example, it is good also as a structure which moves a diaphragm by gas pressure and moves an objective pad by this. Or it is good also as a structure which expands and contracts a bellows tube with a gas pressure, and moves an objective pad by this. Further, a gas pressure cylinder mechanism may be used, or a nozzle / flapper moving mechanism may be used.

  In addition, the tilt drive unit is described as moving the upper table through the objective pad, but the upper table is moved by the most advanced flat plate mover closest to the upper table back surface among the plurality of flat plate movers. The objective pad may be omitted. In the following description, the actuator is described as including an actuator that moves the entire lower table up and down. However, depending on the application, the actuator may be omitted as not moving the entire lower table up and down. In the following, an example in which four are disposed as the tilt drive unit will be described. However, three may be disposed according to the application, and when the tilt direction is known in advance, one or Two arrangements may be used, and five or more arrangements may be used when the load is heavy. Further, the inclined support portion is described as being disposed at the center position of the lower table, but may be disposed at a position other than the center position of the lower table as long as it can be used as a fulcrum.

In the following description, it is assumed that both the upper table and the lower table are parallel flat plates, and that the upper surface of the upper table, its lower surface, the upper surface of the lower table, and its lower surface are flat surfaces. The surface shape can be changed as appropriate according to the specifications of the tilting device. In this case, the plane parallel to the plane direction of the lower table described below is a reference plane for explaining the respective axial directions of the two rotational degrees of freedom of the inclined support portion and the one degree of freedom of translation in the axial direction. As shown, even when the lower table is an uneven surface, a virtual plane serving as a reference for the movement of the upper table can be a plane parallel to the plane direction of the lower table.
In addition, the shape, dimensions, materials, number, and the like described below are examples for explanation, and other conditions can be used according to the purpose of use. For example, although the lower table and the upper table will be described as disk-shaped, they may be rectangular or polygonal. Although the objective pad is described as a disc shape, it may be oval or elliptical.

  Moreover, in each following figure, the same code | symbol is attached | subjected to the same element and the overlapping description is abbreviate | omitted. Further, in the description, the description will be made using the reference numerals described before.

  FIG. 1 is a top view and a cross-sectional view showing a configuration of a gas pressure control type micro tilting device 10. In the following description, the gas pressure control type minute tilting device is simply referred to as a tilting device. 2 is a view showing the sectional view of FIG. 1 in more detail, FIG. 3 is a detailed view of the inclined support portion 50, and FIG. 4 is a view for explaining the detailed configuration of the inclined drive portion 70. In the following drawings, the X, Y, and Z directions are shown as necessary, with the plane parallel to the plane of the lower table 30 being the XY plane and the direction perpendicular to the XY plane being the Z direction. Although the arrangement | positioning attitude | position of the tilting apparatus 10 does not receive a restriction | limiting in particular, below, it demonstrates that the Z direction is made into a gravity direction and the upper direction of a paper surface is upward.

  The tilting device 10 includes a main body housing portion 12, a piston base 20 guided by the main body housing portion 12, a lower table 30 attached to the upper portion of the piston base 20, and an upper table disposed above the lower table 30. 40, an inclination support part 50 and an inclination driving part 70 disposed between the lower table 30 and the upper table 40, a gas pressure control valve 34 for supplying a gap control gas to the inclination driving part 70, and an upper table 40 A gap amount sensor 82 that detects the amount of movement of the motor and a control unit 28 are included.

  The tilting device 10 moves the upper table 40 with respect to the lower table 30 by the tilt driving unit 70 using the gas pressure under the control of the control unit 28, thereby moving the upper table 40 around the tilt support unit 50 as a fulcrum. It is a device having a function of tilting with respect to the lower table 30.

The main body housing 12 has a function as a base of the entire tilting device 10 and is a member having a function as a cylinder for guiding the piston base 20 so as to be movable in the Z direction. In addition, in order to prevent rotation of the piston base 20, it is preferable to provide an appropriate rotation stopper. The main body housing 12 is a cylindrical member having the Z direction as an axial direction and having an opening on the upper side. The cylindrical inner surface serves as a movement guide surface for the piston base 20, and a gas for driving the piston base 20 on the bottom surface. _A supply port 14 to which a gas having a pressure PA is supplied is provided. Further, in order to give an appropriate pressing force to the piston base 20 and to flow a gas through the gap between the outer peripheral surface of the piston base 20 and the cylindrical inner surface of the main body housing portion 12, the step of the piston base 20 is provided. A gas having an appropriate gas pressure is supplied to the upper surface side, and a supply port 124 is provided to supply the gas. Further, an exhaust port 26 is provided in the vicinity of the opening for collecting the gas flowing from the supply port 124 toward the opening and discharging it to the outside.

The piston base 20 is a cylindrical member lower table 30 is attached at a top surface, a bottom surface, and a gas receiving surface for receiving the gas pressure P _A, which is movable in the Z-direction while being guided by the cylindrical inner surface of the main housing section 12 It has a function as a piston. Inside the piston base 20 and the lower table 30, gas flow paths 22 and 32 connected to an airtight housing portion 44 formed between the lower table 30 and the upper table 40 are provided. The gas flow paths 22 and 32 are exhaust flow paths for collecting the gas flowing from the supply port 124 to the bottom surface side of the main housing 12 and temporarily flowing the gas to the airtight housing 44. Note that the gas collected in the airtight container 44 is discharged to the outside from the exhaust port 126 provided in the lower table 30 again.

  As described above, the gas blown out from the supply port 124 passes through the gap between the outer peripheral surface of the piston base 20 and the cylindrical inner surface of the main body housing 12 at the upper opening side and the lower bottom side. It flows in. A shallow groove 24 is provided on the outer peripheral side surface of the piston base 20 along the gap. The shallow groove 24 functions as a surface restriction when the gas flows along the gap, whereby the piston base 20 is supported by the main body housing 12 so as to be movable in the Z direction with a stable gap interval. Of the gas that has flowed through the gap, the gas that has flowed to the upper opening side is produced from the exhaust port 26 to the outside. The gas that has flowed to the lower bottom surface side is discharged from the exhaust port 126 to the outside through the gas flow path 22 of the piston base 20, the gas flow path 32 of the lower table 30, and the airtight housing portion 44.

  The lower table 30 is a stage table attached to the piston table 20, and the upper table 40 is slightly moved and tilted with reference to this table. The lower table 30 is a disk-shaped member having substantially the same outer diameter as the upper table 40, and one end of the inclined support portion 50 is attached to the upper surface of the lower table 30 so as to be in the center position. Also, on the upper surface, four inclined drives are provided on the outer peripheral side in the plane of the lower table 30, that is, on the outer peripheral side at a predetermined distance from the inclined support part 50 in the plane perpendicular to the Z direction. The arrangement position of the unit 70 is set. Other configurations of the lower table 30 will be described later in relation to the tilt driving unit 70.

  The upper table 40 is, for example, a stage base that holds a measurement object, a processing object, and the like. In the example of FIG. 1, a disk-like member is used and has a circular stage shape. The other end of the inclined support portion 50 is attached at a position corresponding to the center position of the disk-shaped member.

  The stretchable wall portion 42 has a bottom surface side connection portion on the outer peripheral portion of the lower table 30, and has an upper surface side connection portion on the outer peripheral portion of the upper table 40, along the outer periphery of the lower table 30 and the upper table 40. It is a bellows-like elastic member arranged in an annular shape. The stretchable wall portion 42 is connected to both the lower table 30 and the upper table 40 in an airtight structure. As the stretchable wall portion 42, a bellows-like member made of an appropriate plastic material or rubber material, or a bellows-like member made of a metal thin plate can be used. In some cases, a bellows-like elastic member made of metal or rubber may be used instead of the bellows-like elastic member. Alternatively, when a small amount of gas leakage can be allowed, sleeves having different inner diameters may be arranged in the radial direction over several stages, and a structure that sequentially moves in the axial direction to a so-called bamboo slab shape may be used.

  Thus, a cylindrical airtight space is formed by the upper surface of the lower table 30, the lower surface of the upper table 40, and the inner surface of the telescopic wall portion 42. This airtight space is a space that accommodates the inclined support portion 50 and the four inclined drive portions 70 inside, and can be referred to as an airtight accommodating portion 44.

  As described above, the inclined support portion 50 disposed in the airtight housing portion 44 is a connection member having one end attached to the lower table 30 and the other end attached to the upper table 40. In the example of FIG. 1, the inclined support portion 50 is attached to the center portion of the lower table 30 and the upper table 40.

  FIG. 3 is a detailed view of the inclined support portion 50. The inclined support portion 50 includes an attachment portion 52 to the lower table 30, an attachment portion 54 to the upper table 40, and a column portion 56 that connects the two attachment portions 52 and 54. Here, the two attachment portions 52 and 54 are disk-shaped members having appropriate thicknesses. Moreover, the column part 56 is a cylindrical member and is disposed so as to connect the central parts of these two disk members. The length of the column portion 56 is set to be sufficiently longer than the diameter thereof, and the diameters of the two attachment portions 52 and 54 are set to be sufficiently larger than the diameter of the column portion 56.

  Under such setting, the rigidity of the inclined support portion 50 in the direction in which the column portion 56 is rotated and bent can be reduced as compared with the rigidity along the axial direction of the column portion 56. Accordingly, the inclined support portion 50 can be elastically deformed so that the column portion 56 is flexed by appropriately rotating its axial direction. In FIG. 3, the deflection of the column part 56 and the movement of the attachment part 54 when the attachment part 52 is fixed are indicated by broken lines. In FIG. 3, rotation about the Y axis perpendicular to the paper surface is shown, but since the column portion 56 is cylindrical, it also has a degree of freedom of rotation about the X axis perpendicular to the Y axis. That is, the inclined support portion 50 in FIG. 3 has two-axis rotational degrees of freedom around two axes orthogonal to each other in the XY plane parallel to the plane direction of the lower table 30. Moreover, since the pillar part 56 is expanded-contracted to an axial direction by elastic deformation, it also has the translational movement freedom degree of a Z direction.

  1 and 2 again, the inclination driving unit 70 provided in the airtight housing unit 44 has a function of moving the upper table 40 with respect to the lower table 30 in the Z-axis direction by controlling the gas pressure. Control actuator.

  As described above, the tilt drive unit 70 is arranged at the outer peripheral side at a predetermined distance from the tilt support unit 50 on the upper surface of the lower table 30. In the example of FIG. 1, four tilt drive units 70 are arranged at equal intervals in the circumferential direction on a radius that is equidistant from the tilt support unit 50 arranged at the center point of the lower table 30 in the axial direction. .

  FIG. 4 is an enlarged view of the periphery of one tilt driving unit 70. As shown here, on the upper surface of the lower table 30, an annular recess 36 having a central hole is provided at the position where the inclined drive unit 70 is arranged, and a central shaft 80 is fixedly installed in the annular recess 36. Arranged. The tilt drive unit 70 includes the central shaft 80, the objective pad 72, a gap amount sensor 82 disposed in the central shaft 80, and a plurality of flat plate movers 90 arranged in the axial direction around the central shaft 80. Consists of.

  The objective pad 72 is a flat member for supporting the upper table 40 in a non-contact manner, and the upper surface thereof is an objective upper surface 73 facing the upper table 40. The objective upper surface 73 is processed into a flat surface so that gas flows smoothly on the surface. Such an objective pad 72 may be formed into a disk shape using an appropriate metal material, ceramic material, plastic material, or the like. An appropriate surface treatment can be performed on the surface of the objective pad 72.

A gas outlet 74 provided at the center of the objective upper surface 73 is connected to a gas supply path 35 provided inside the lower table 30 from the center hole of the annular recess 36. The gas supply path 35 opens at an appropriate position such as the outer periphery of the lower surface of the lower table 30 and is connected to the gas pressure control valve 34. As will be described later, a gap control gas having a gas pressure P _S is supplied from the gas pressure control valve 34.

  FIG. 5 is a diagram illustrating a state in which the tilt driving unit 70 is viewed from the object upper surface 73 side, which is the upper surface of the object pad 72. As shown here, the objective upper surface 73 is provided with a plurality of narrow grooves 78 that are shallow and narrow grooves extending radially from the gas outlet 74. The narrow grooves 78 extending radially form a recess 76 that is shared on the inner diameter side of the disk. That is, on the upper surface of the objective pad 72, the inner diameter side portion has a thickness of a portion with a predetermined radius from the center of the gas outlet 74 to form a recess 76, and the recess 76 is a starting point of each narrow groove 78. A narrow groove 78 extends in a radial direction from the point by a predetermined length. The distal end portion of the narrow groove 78 extending in the radial direction spreads on both sides in the circumferential direction, and stops its expansion to the extent that it does not connect with the circumferential spread of the adjacent narrow groove 78. The shape of the recess 76 and the narrow groove 78 is an example as a surface stop, and may be a stop having another appropriate shape.

  In this way, the depression 76 and the narrow groove 78 are provided so as to exert a throttling effect when gas flows radially from the gas outlet 74 on the objective upper surface 73. That is, the gas flows in the gap between the two surfaces facing the objective upper surface 73 and the back surface of the upper table 40, and the gas flowing through the recess 76 and the narrow groove 78 overflows on the flat plate surface at the end of the narrow groove 78. Sometimes, the flow path becomes narrower and narrowed, resulting in a so-called surface restriction. The effect of this surface restriction stabilizes the flow between the two surfaces and also stabilizes the distance between the two surfaces.

  The depth of the recess 76 and the narrow groove 78 can be about 10 μm to about 20 μm. If the outer shape of the objective pad 72 is about 30 mm, for example, the radial width of the recess 76 can be about 1 mm to about 6 mm, and the width of the narrow groove 78 can be about 0.2 mm to about 2 mm.

  Returning to FIG. 4 again, the central shaft 80 is a hollow shaft that is fixedly disposed in an annular recess 36 provided on the upper surface side of the lower table 30. As described above, since the annular recess 36 has an opening at the center, the central through hole, which is the hollow portion of the central axis, serves as a gas flow path with the central opening of the annular recess 36. Fluidly connected.

  FIG. 6 shows the state of the central axis 80. The central shaft 80 has a central through hole at the center thereof, and the outer shape is a hexagonal star ridge shape, and a plurality of communication holes 84 communicating with the central through hole are provided in the star-shaped valley portion. As described above, since the central shaft 80 is fixedly disposed in the annular recess 36 connected to the gas supply path 35, the central through hole of the central shaft 80 is supplied with a gap control gas. A gap control gas that is communicated with the gas supply path 35 and supplied from the gas pressure control valve 34 can be blown out. Then, the blown-out gas flows in the radial direction toward each flat plate movable element 90 in the airtight housing portion 44, and in the axial direction, flows upward from the star-shaped valley to the gas outlet 74.

  The gap amount sensor 82 disposed in the central through hole of the central shaft 80 is a gap amount detection unit that detects the movement amount of the upper table 40 with respect to the lower table 30 based on the gap amount with respect to the objective pad 72. is there. The outer shape of the gap amount sensor 82 is smaller than the inner diameter of the central through hole, and the gas supplied from the gas supply path 35 can sufficiently flow to the gas outlet 74 and the communication hole 84. The detection data of the gap amount sensor 82 is transmitted to the control unit 28 through an appropriate communication line. As the gap amount sensor 82, a capacitive sensor, a magnetic sensor, an optical sensor, or the like can be used.

  Returning to FIG. 4 again, the plurality of flat plate movable elements 90 arranged around the central axis 80 have a function of generating a minute displacement for moving the objective pad 72 relative to the lower table 30. A state of the flat plate movable element 90 is shown in FIG.

  The flat plate movable element 90 is a donut-shaped member having a concentric opening 92 at the center of the disk. The flat plate movable element 90 is provided with a plurality of fine grooves 96 which are shallow and thin grooves extending radially from the center on one surface of the flat plate surface. The narrow grooves 96 extending radially form a recess 94 that is shared on the inner diameter side of the disk. That is, the portion on the inner diameter side of the flat plate movable element 90 is formed with a thickness of a portion having a predetermined radius from the center to form a recess 94, and the recess 94 becomes a starting point of each narrow groove 96, and from there The length of the narrow groove 96 extends in the radial direction. The distal end portion of the narrow groove 96 extending in the radial direction spreads on both sides in the circumferential direction there, and stops its expansion to the extent that it does not connect with the circumferential spread of the adjacent narrow groove 96. The shape of the indentation 94 and the narrow groove 96 is an example of a surface stop, and may be a surface stop having another appropriate shape. The indentation 94 and the narrow groove 96 may be provided on both sides of the flat plate movable element 90.

  In this way, the depression 94 and the narrow groove 96 are provided so as to exert a throttling effect when gas flows in the radial direction along the surface of the flat plate movable element 90. That is, the flat plate surface of the flat plate movable element 90 faces the other surface, gas flows into the gap between the two surfaces, and the gas flowing through the recess 94 and the narrow groove 96 is flattened at the end of the narrow groove 96 or the like. When the surface overflows, the flow path is narrowed and narrowed, so-called surface throttling. The effect of this surface restriction stabilizes the flow between the two surfaces and also stabilizes the distance between the two surfaces.

  An example of the dimensions of the flat plate mover 90 is as follows. The outer diameter is about 30 mm to about 40 mm, the inner diameter is about 10 mm to 15 mm, the plate thickness is about 0.1 mm to about 0.2 mm, the indentation 94 and the narrow groove 96. The depth can be about 13 μm to about 17 μm, the radial width of the recess 94 can be about 2 mm to 4 mm, and the width of the narrow groove 96 can be about 0.2 mm. These are only examples, and can be made smaller or larger depending on the application. In FIG. 7, the depth of the narrow groove 96 is exaggerated and enlarged. The flat plate movable element 90 can be obtained by processing a metal disc such as SUS, a ceramic plate, or a plastic plate.

  Returning to FIG. 4 again, the plurality of flat plate movers 90 are arranged around the central axis 80 in a stacked manner along the axial direction. Then, a gap control gas flows through the communication hole 84 on the side surface of the central shaft 80 in the gap between the adjacent flat plate movable elements 90. In addition, the gap between the upper surface of the flat plate mover 90 located on the uppermost layer of the plurality of flat plate movers 90 and the bottom surface of the objective pad 72, the lower surface of the flat plate mover 90 located on the lowermost layer, and the lower table 30. Similarly, the gap control gas flows through the communication hole 84 on the side surface of the central shaft 80 in the gap between the upper surface of the central shaft 80 and the upper surface.

  Assuming that N plate movers 90 are arranged between the objective pad 72 and the lower table 30, an N + 1 gap is formed between the objective pad 72 and the lower table 30. The gap control gas flows through these gaps. Then, a pressing force is applied to the objective pad 72 from the weight of the upper table 40 or from the inclined drive unit 70 on the opposite side with the inclined support unit 50 as a fulcrum.

Here, when the pressing force F acts toward each flat plate movable element 90 by the objective pad 72, the flow of gas flowing through these gaps shows an action as a so-called gas bearing. That is, by controlling the gas pressure P _S of the clearance control gas, it is possible to adjust the amount of these clearances while balanced with the pressing force F, thereby, the axial direction of the central axis 80 of the flat plate armature 90, i.e. The objective pad 72 can be finely moved in the direction in which the height position of the upper table 40 is changed.

For example, if the gas pressure P _S of the gap control gas is changed by + ΔP, the amount of each gap can be changed by + Δs. The gas pressure P _S , the pressing force F, and the like can be experimentally determined. Here, since Δs / ΔP is determined for each gap, if the number of gaps is N + 1, the total axial movement amount of the plurality of plate movable elements 90 is (N + 1) × Δs, and the movement amount However, it can be adjusted by increasing / decreasing the number of flat plate movers 90.

As an example, in dimension of the flat plate armature 90, a nominal standard value adjacent the gap is about 10 [mu] m, when about 0.2MPa to P _S, (gap variation / gas pressure variation) = (5 [mu] m /0.1 MPa). As described above, since the thickness of the flat plate movable element 90 is about 0.1 mm to about 0.2 mm, the total length in the axial direction of the twelve flat plate movable elements 90 is about 1 even if N + 1 = 13. .2 mm to about 2.4 mm. If ΔP is set to 0.15 MPa, the movement amount of 13 × 7.5 μm = 97.5 μm can be given to the objective pad 72 by the twelve flat plate movable elements 90. That is, a moving amount of about 100 μm can be given to the total length of about 1 mm to 2 mm. In addition, the amount of movement is determined by Δs / ΔP, and the controllability of the gas pressure is very good. Therefore, the accuracy of the amount of movement can be kept extremely high for the entire stroke.

  As described above, between the objective pad 72 and the lower table 30, the gap control gas is supplied from the communication hole 84 on the side surface of the central shaft 80 and flows into the gaps between the plurality of plate movable elements 90. The flowing gas flows out into the space of the airtight housing portion 44 between the outer periphery of the plurality of plate movable elements 90 and the stretchable wall portion 42. As already described, gas also flows from the gas flow path 32 of the lower table 30. These gases are discharged to the outside from an exhaust port 126 provided in the airtight housing portion 44. Note that the gas exhausted to the outside can be recovered and used again as the working gas of the gas pressure control valve 34.

Next, the control unit 28 in FIGS. 1 and 2 will be described. The control unit 28 calculates the amount of movement of each of the four tilt driving units 70 in the Z direction in order to tilt the upper table 40 with respect to the lower table 30 by a minute angle, and uses this as the movement amount command value. compared 82 and the detection value of the movement command value, to the deviation to zero, having to control the corresponding gas pressure control valve 34 functions to output the gas pressure P _S of the clearance control gas. Further, if necessary, to move the entire lower table 30 in the Z direction, to calculate the gas pressure P _A required to move the piston base 20 by a predetermined moving amount, the gas pressure generated not shown parts hand, has a function to output the gas pressure P _a.

  Since the latter function is the same as the drive control of the so-called piston / cylinder mechanism, detailed description thereof is omitted. The former fine angle tilt control can be performed by the following procedure. For example, as shown in FIG. 1, it is assumed that the upper table 40 is inclined with respect to the lower table 30 by a minute angle −α counterclockwise around the Y axis. In this case, the tilt driving unit 70 shown as C in FIG. 1 is moved by a predetermined amount in the + Z direction, and the tilt driving unit 70 shown as A is moved by a predetermined amount in the −Z direction. It is assumed that the two inclined drive units 70 indicated as B and D do not change the free state, that is, the gas pressure of the gap control gas. The amount of movement in the + Z direction of the tilt driving unit 70 shown as C and the amount of movement in the −Z direction of the tilt driving unit 70 shown as A are substantially the same in size and opposite to each other. is there. The magnitude of the amount of movement can be obtained from the distance between the arrangement position of the inclined support part 50 serving as a fulcrum and the arrangement position of the inclination driving part 70 and the target minute angle α.

When the necessary movement amount of the movement amount of the tilt driving unit 70 is obtained, the change amount ΔP of the gas pressure of the gap control gas corresponding to the necessary movement amount is obtained. The calculation, as described in connection with the flat armature 90, each gap amount of variation + Delta] s when changing + [Delta] P gas pressure P _S of the control gas for clearance system, the total number of the flat plate armature 90 N Therefore, since the total axial movement amount of the plurality of plate movable elements 90 is (N + 1) × Δs, Δs can be obtained by assuming that this is equal to the necessary movement amount, and ΔP corresponding to this can be obtained. In this way, when the amount of change in the gas pressure of the gap control gas necessary for the operation of each tilt drive unit 70 is obtained, the gap control of the gas pressure corresponding to the amount of change in gas pressure is sent to the corresponding gas pressure control valve 34. Command to output gas.

  Thereby, the upper table 40 is rotationally driven so as to be inclined with respect to the lower table 30. The gas pressure control of the gap control gas can be performed in an open loop, but feedback control can also be performed using the gap amount sensor 82. In this case, the movement amount of the upper table 40 is detected by the gap amount sensor 82, and the detection result is returned to the control unit 28. Then, it is possible to perform feedback control in which the deviation between the detected actual movement amount and the movement amount command value is zero.

  In the above description, the minute inclination around the Y axis has been described, but even if the axial direction of the inclination rotation is the X direction, the operation of the inclination driving unit 70 indicated by B and the inclination driving unit 70 indicated by D in FIG. By controlling this, it is possible to control the target tilt angle. In addition, when the rotation axis of the minute inclination does not coincide with the X axis or the Y axis, the target inclination angle can be controlled by controlling the operations of the four inclination driving units 70. Further, the upper table 40 can be moved minutely with respect to the lower table 30 by driving the respective tilt driving units 70 so as to have the same movement amount in the same direction. When the plurality of tilt driving units 70 are independently operated, the upper table 40 is tilted with respect to the lower table 30 along with a slight movement.

  In the above description, the inclined support portion is described as being composed of two disc-shaped attachment portions and a columnar column portion connecting the two attachment portions. Even if it is a structure other than this, what is necessary is just to have the biaxial rotation freedom degree around each of the two axes orthogonal to each other in the XY plane parallel to the planar direction of the lower table 30. In addition to this, it may have a uniaxial translational freedom in the Z direction perpendicular to the XY plane. 8 to 11 are diagrams illustrating another example of the inclined support portion. In the following description, since the XY plane is also a plane parallel to the plane direction of the attachment portion 52, the description will be made using a plane parallel to the plane direction of the attachment portion 52 instead of the XY plane.

  8 is provided with a ball 102 attached to the attachment portion 52 side and a slide bearing 104 corresponding to the ball 102 provided on the attachment portion 54 side. The ball 102 may be attached to the attachment portion 54, and the slide bearing 104 may be provided on the attachment portion 52. With this configuration, it is possible to have a two-axis rotational degree of freedom around each of two axes orthogonal to each other in a plane parallel to the plane direction of the mounting portion 52. Even in this case, the elasticity of the column portion of the attachment portion 52 has a small degree of freedom in translation in a direction perpendicular to the plane direction of the attachment portion 52.

  In FIG. 9, the inclined support portion 110 in FIG. 9A uses a part called a cross spring 112 shown in FIG. 9B. The cross spring 112 has a spring body 116 extending in four directions orthogonal to each other from a cube 114 at the center, and an attachment terminal portion 118 is provided at the tip. As the spring body 116, for example, a torsion spring can be used. As shown in FIG. 9A, the inclined support portion 110 is configured by attaching the cube 114 of the cross spring 112 to the attachment portion 52 and fixing the four attachment terminal portions 118 of the cross spring 112 to the attachment portion 55. The With this configuration, it is possible to have a two-axis rotational degree of freedom around each of two axes orthogonal to each other in a plane parallel to the plane direction of the mounting portion 52. Further, due to the elasticity of the torsion spring, there is a degree of freedom in translation in a direction perpendicular to the plane direction of the mounting portion 52.

  The inclined support part 120 of FIG. 10 has a bellows 122 attached between the attachment part 52 and the attachment part 54. Since the bellows 122 has both appropriate rigidity and appropriate flexibility, this structure has two-axis rotational degrees of freedom about two axes orthogonal to each other in a plane parallel to the plane direction of the mounting portion 52. Furthermore, it is possible to have one-axis translational freedom in a direction perpendicular to the plane of the mounting portion 52.

  In the inclined support portion 130 of FIG. 11, a helical spring 132 is attached between the attachment portion 52 and the attachment portion 54. The helical spring 132 is processed so that a thin plate is spirally continuous, and is a component having both appropriate rigidity and appropriate flexibility. With this configuration, biaxial rotation freedom around each of the two axes orthogonal to each other in a plane parallel to the plane direction of the mounting portion 52, and one-axis translation in a direction perpendicular to the plane of the mounting portion 52 It can have a degree of freedom.

  In the above description, the opening 92 at the center of the flat plate movable element 90 and the central shaft 80 are not directly fixed, and the flat plate movable elements 90 are slid and held by the central shaft 80 so as not to shift in the radial direction. Has been. In addition to the holding of the flat plate movable element 90, each flat plate movable element 90 can be held with a viscoelastic material on the central axis. As the viscoelastic material, plastic, rubber or the like can be used. In this case, the central axis may be a simple cylindrical axis instead of the star-ring shape.

  FIG. 12 is a diagram illustrating an example in which a flat plate movable element is held on the central axis using a cloud spring. In the flat plate mover 140, as in the flat plate mover 90 described with reference to FIG. 7, a circular plate 142 is provided with a recess 146 on the inner diameter side and a narrow groove 148 extending in the radial direction from the recess 146. A cloud spring 144 is provided as a thin plate member that connects the inner diameter side portion of the circular plate 142 and the outer shape of the central shaft 81. Here, the cloud spring 144 is used as a holding member whose rigidity with respect to the displacement of the central shaft 81 in the axial direction is small with respect to displacement in the radial direction.

  The pattern of the cloud spring 144 is formed by appropriately combining the shape of the portion extending in the radial direction and the shape of the portion extending in the circumferential direction. Specifically, it has a complicated and winding shape, whereby a window-like opening is formed between the patterns, and gas can flow through the opening window. The cloud spring 144 can be obtained by etching a thin metal plate into a predetermined pattern. For example, it can be obtained by performing etching or electric discharge machining on a SUS plate having a thickness of about 0.1 mm. A cloud spring is a simple name used because its shape pattern is twisted and resembles a cloud shape, and any other spring can be used if it has a small rigidity in the axial direction and a large rigidity in the radial direction. It may be a designation.

  FIG. 13 is a view showing a connection portion between the cloud spring 144 and the circular plate 142 of the flat plate movable element 140. A suitable adhesive can be used for the connection between them. In some cases, the thickness of the disc 142 can be reduced and integrated with the cloud spring 144.

  By adopting such a configuration, the flat plate movable element 140 held by the central shaft 81 via the cloud spring 144 is relatively easy to move in the axial direction of the central shaft 81, but in the radial direction of the flat plate. That is, it is relatively difficult to move in a direction perpendicular to the axial direction of the central axis 81. In other words, the flat plate movable element 140 has a characteristic that the axial direction of the central shaft 81 is the thrust direction and the degree of freedom in the thrust direction is large, but the movement in the radial direction perpendicular thereto is restricted. The central axis 81 may be a simple circular pipe.

  In the above description, the gap control gas is blown out from the blowout port at the center of the objective pad. However, it is possible to adopt a structure in which the blown out gas has a rectifying property as a smooth flow. FIG. 14 shows some examples of an objective pad that can impart rectification to the gas to be blown out. In these examples, the gap amount sensor is not shown. In these examples, the gap amount sensor can be easily installed by providing a separate appropriate opening.

  FIG. 14A shows a case where a porous plate 154 is provided on the upper surface side of the objective pad 150. The gap control gas supplied from the center opening 152 is rectified by passing through the porous plate 154 and becomes a smooth flow.

  FIG. 14B shows a case where a surface stop 164 is provided on the upper surface of the objective pad 160. As the surface stop, the shallow groove structure described with reference to FIG. 5 can be used. The flow of the gap control gas supplied from the central opening can be made smooth by the surface restriction. In addition, an appropriate orifice diaphragm or the like can be provided as the front stage diaphragm 162 at the center opening.

  FIG. 14C shows a case where a tapered groove 172 is provided on the upper surface of the objective pad 170. As the tapered groove 172, a groove whose groove depth gradually decreases from the central opening toward the outer periphery can be used. The flow supplied from the central opening by the taper groove 172 gradually spreads toward the outer periphery, whereby a smooth flow can be obtained. Again, the front stop 162 can be used in the central opening. A stepped groove or the like can be used instead of the tapered groove.

  In the above description, the space between the lower table and the upper table is defined as one airtight space as the airtight accommodating portion, and four inclined driving portions are disposed in the one airtight space. This can also be configured as an independent airtight housing for each tilt drive. FIG. 15 is a diagram illustrating an example in which the stretchable wall portions 42 and 43 are provided so as to surround the respective tilt drive units 70, and one tilt drive unit 70 is arranged in each of four independent airtight storage units 45. . In this case, the gas discharge path 33 is provided so as to have an opening in each hermetic accommodating portion 45.

  As described above, by providing the airtight housing portion in a plurality of portions, gas leakage from the airtight housing portion to the outside can be minimized. Therefore, as long as the airtight container is kept airtight even in a reduced pressure atmosphere and a vacuum atmosphere, the tilt driving part can be operated normally. Furthermore, to ensure operation in a reduced-pressure atmosphere or vacuum atmosphere, vacuuming is performed outside the hermetic housing part, and a gas that may slightly leak is sucked so that it does not leak to the outside. Good.

  FIG. 16 is a diagram illustrating an example of a configuration in which the inner central space is vacuum-sucked from the suction port 202 and vacuum suction is performed by the plurality of suction ports 204 on the outer side of the stretchable wall portion 42. The plurality of suction ports 204 are preferably arranged on the mating surface of the lower table 200 and the upper table 210 side by side from the inner peripheral side to the outer peripheral side. In this case, it is preferable to increase the suction force toward the outer side, such as low vacuum, medium vacuum, and high vacuum from the inner peripheral side. The suction port 204 in the central space is an internal space in which almost no gas leaks to the outside, and therefore may have a low degree of vacuum.

  In FIG. 17, vacuum suction of the inner central space from the suction port 202 is the same as in the case of FIG. 16, but the membrane 232 having elasticity on the outer peripheral portion of the upper table 230 is further outside the stretchable wall portion 42. FIG. In this case, since the membrane 232 has elasticity, the outermost peripheral part of the upper table 210 is firmly fixed to the outermost peripheral part of the lower table 220. Appropriate seal members 214 are provided on the mating surfaces of the fixed portions, whereby the leakage of gas to the outside can be minimized. In this structure, since the upper table 210 can be supported by the membrane 232, the inclined support portion 50 can be omitted depending on circumstances.

It is a figure which shows the structure of the gas pressure control-type micro inclination apparatus of embodiment which concerns on this invention with a top view and sectional drawing. It is a figure which shows sectional drawing of FIG. 1 in detail. It is a figure which shows the inclination support part of embodiment which concerns on this invention. It is an enlarged view of the periphery of the inclination drive part of embodiment which concerns on this invention. It is a figure which shows a mode that the inclination drive part of embodiment which concerns on this invention was seen from the objective upper surface side which is the upper surface of an objective pad. In embodiment which concerns on this invention, it is a figure which shows the mode of a central axis. In embodiment which concerns on this invention, it is a figure which shows the mode of a flat needle | mover. It is a figure explaining the other example of the inclination support part of embodiment which concerns on this invention. It is a figure explaining the further another example of the inclination support part of embodiment which concerns on this invention. It is a figure explaining another example of the inclination support part of embodiment which concerns on this invention. It is a figure explaining another example of the inclination support part of embodiment which concerns on this invention. In embodiment which concerns on this invention, it is a figure which shows the example which hold | maintains a flat needle | mover to a central axis using a cloud shaped spring. In embodiment which concerns on this invention, it is a figure which shows the connection part between a cloud-shaped spring and the disc of a flat needle | mover. In embodiment which concerns on this invention, it is a figure which shows some examples of an objective pad. In embodiment which concerns on this invention, it is a figure which shows the example which isolate | separates and arrange | positions an airtight accommodating part for every inclination drive part. In embodiment which concerns on this invention, it is a figure which shows the example of the structure which vacuum-sucks the outer side of an expansion-contraction wall part. In embodiment which concerns on this invention, it is a figure which shows the case where the membrane which has elasticity is provided in the outer peripheral part of an upper table.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 (Gas pressure control type | mold minute) inclination apparatus, 12 Main body housing | casing part, 14,124 Supply port, 20 Piston stand, 22,32 Gas flow path, 24 Shallow groove, 26,126 Exhaust port, 28 Control part, 30, 200, 220 Lower table, 33 Gas discharge path, 34 Gas pressure control valve, 35 Gas supply path, 36, 76, 94, 146 Recessed, 40, 210, 230 Upper table, 42, 43 Telescopic wall, 44, 45, 206 Airtight housing part, 50, 100, 110, 120, 130 Inclined support part, 52, 54, 55 Mounting part, 56 Column part, 70 Inclined drive part, 72, 150, 160, 170 Objective pad, 73 Objective upper surface, 74 Gas outlet, 78, 96, 148 Narrow groove, 80, 81 Central axis, 82 Clearance sensor, 84 Communication hole, 90, 140 Flat plate mover, 92 Opening, 102 104, plain bearing, 112 cross spring, 114 cube, 116 spring body, 118 mounting terminal, 122 bellows, 132 helical spring, 142 disc, 144 cloud spring, 152 center opening, 154 porous plate, 162 Diaphragm, 164 Surface choke, 172 Tapered groove, 202,204 Suction port, 214 Seal member, 232 Membrane.

Claims (7)

The lower table,
An upper table disposed above the lower table;
A plurality of arrangement positions are arranged between the lower table and the upper table. Under the control of the gas pressure, the upper table is moved minutely independently in the vertical axis direction at each arrangement position with respect to the lower table. On the other hand, a plurality of tilt drive units that slightly tilt the upper table together with the minute movement,
A gas pressure control type micro tilting device comprising: An inclined support portion having one end attached to the lower table, the other end attached to the upper table, and having two-axis rotational degrees of freedom about two axes parallel to the plane direction of the lower table and perpendicular to each other;
It is arranged between the lower table and the upper table at a plurality of arrangement positions at a predetermined distance from the inclined support portion within the plane of the lower table, and the upper table is attached to the lower table under the control of the gas pressure. A plurality of tilt driving units that micro-moves independently in the vertical axis direction at each arrangement position, and tilts the upper table with the micro-moving and micro-tilting with respect to the lower table with the tilt support portion as a fulcrum
A gas pressure control type micro tilting device comprising: In the gas pressure control type micro inclination device according to claim 2,
The tilt drive is
An objective pad having a gas outlet on the upper surface of the objective facing the back surface of the upper table;
A flat plate movable element having a through-window through which gas can flow and arranged in parallel between a pad back surface opposite to the object upper surface of the object pad and an upper surface of the lower table;
An airtight structure is formed between the upper table and the lower table by the stretchable wall portions that can be expanded and contracted in the alignment axis direction of the plurality of flat plate movers, and the plurality of flat plate movers are moved along the alignment axis direction in which the flat plate movers are aligned. An airtight housing portion for accommodating the housing;
Adjacent to the gas blowing part of the objective pad, the through window of each flat plate mover, the pad side gap that is the gap between the most advanced flat plate mover facing the pad back surface and the pad back surface among the plurality of flat plate movers The gaps between the movable elements, which are the gaps between the flat plate-shaped movable elements, and the gaps between the rearmost flat-plate movable element facing the bottom surface of the lower table and the bottom surface of the housing portion among the plurality of flat plate-shaped movable elements. A gap control gas supply means for supplying a gap control gas to the bottom gap;
With
A gas characterized by controlling the gas pressure of the gap control gas and finely moving the upper table in the vertical axis direction with respect to the lower table while adjusting the distance between the gaps while balancing the pressing force from the upper table. Pressure control type fine tilting device. In the gas pressure control type micro tilting device according to claim 3,
A gas pressure support mechanism for a plate material, wherein the expansion / contraction wall portion of the hermetic housing portion is formed of a bellows-type expansion / contraction member or a bellows-type expansion / contraction member. In the gas pressure control type micro tilting device according to claim 3,
A gas pressure control type micro-tilt device, characterized in that it has a vacuum suction means that is disposed outside the hermetic container and sucks gas leaking from the hermetic container. In the gas pressure control type micro inclination device according to claim 3,
A gap amount detecting means for detecting a gap amount between the objective upper surface of the objective pad and the back surface of the upper table;
A control unit for controlling the gas pressure of the gap control gas according to the detection result of the gap amount detection means;
A gas pressure control type micro tilting device comprising: In the gas pressure control type micro tilting device according to claim 2,
A gas pressure control type minute tilting device comprising a gas pressure control actuator for moving and driving the lower table in the vertical axis direction.

Images