JP4962780B2 - STAGE DEVICE, FLOAT CONTROL METHOD, AND EXPOSURE DEVICE USING STAGE DEVICE - Google Patents

Description

  The present invention relates to a stage apparatus in which a movable base is supported in a non-contact manner, driven by a linear motor, and positioned at an arbitrary position, and a driving method thereof. The present invention also relates to an exposure apparatus provided with this stage apparatus.

In order to transfer a circuit board of a semiconductor integrated circuit or a liquid crystal substrate to a photosensitive substrate, a projection exposure apparatus is used, and two methods have been proposed.
The stage of the first projection exposure apparatus includes a support platform (for example, Patent Document 1).
As shown in FIG. 4, the stage apparatus 100 includes a fixed frame 101, a slider 102 that is movable in the X direction with respect to the fixed frame 101, and a support platform 103 that holds the semiconductor wafer W. The support platform 103 is attached to the slider 102 so as to move along the Y direction. The stage apparatus 100 further includes two X linear motors 105 that move the slider 102 in the X direction, and a Y linear motor 106 that moves the support platform 104 in the Y direction. When the support platform 104 is supported in a non-contact manner, a high-precision displacement sensor such as a capacitance type is used to measure the gap between the support platform 104 and the fixed frame 101. The stage apparatus 100 maintains the support platform 104 in a normal posture and accurately positions the support platform 104 in the X direction and the Y direction.
The stage of the second projection exposure apparatus includes a magnetic levitation device (for example, Patent Document 2).
As shown in FIGS. 5A and 5B, the stage apparatus includes a levitation electromagnet 4, a Y-axis linear motor 5, an X-axis linear motor 6, a two-dimensional linear sensor 8, and the like. And a movable base 3 positioned from the Y-axis linear motor and the X-axis linear motor 6.
The fixing base 2 has a substantially rectangular shape with both ends in the Y-axis direction open and a groove-like opening extending in the Y-axis direction on the lower surface, and a hole 9 is provided in the top plate. 9 penetrates along the optical axis in order to pass the optical axis of the optical measuring instrument which measures the position of the movable table 3 or the transported object 15. A hole 16 is provided at a place where the movable axis 3 intersects so that the optical axis hits the object to be conveyed 15. The fixed base 2 includes two sets of Y-axis linear motors 5 and one set of X-axis linear motors 6 arranged in parallel to each other. In addition, the levitation electromagnet 4, the Y-axis linear motor 5 and the stator 51 of the X-axis linear motor 6 are arranged vertically symmetrically on the top and bottom plates of the fixed base 2, and the levitation electromagnet 4 is divided into four parts. As shown to Fig.1 (a), it arrange | positions at intervals and avoiding an optical axis.
The movable table 3 is supported by a levitating electromagnet 4 attached to the fixed table 2 and can move freely in the X-axis and Y-axis directions. In addition, the levitating magnetic piece 17, the Y-axis linear motor 5, and the mover 61 of the X-axis linear motor 6 are disposed on the upper and lower surfaces of the movable table 3. The movable table 3 is driven by the X-axis linear motor 6 and the Y-axis linear motor 5 and moves freely in the X-axis and Y-axis directions. However, in this embodiment, the stroke in the X-axis direction is smaller than that in the Y-axis direction.
The two-dimensional linear scale 7 is fixed in parallel with the Y-axis linear motor 5 in the middle of the movable table 3 and between the two sets of Y-axis linear motors 5. The two-dimensional linear scale 7 is a linear scale inscribed with scales for detecting positions in the X-axis direction and the Y-axis direction. For example, a two-axis coordinate measuring system (PP271R, PP281R) manufactured by HEIDENHAIN is used.
Two two-dimensional linear sensors 8 are attached to the fixed base 2 at intervals in the Y-axis direction. The two-dimensional linear sensor 8 is a sensor that reads the scale of the two-dimensional linear scale 7 and obtains the position in the X-axis direction and the Y-axis direction. For example, the two-dimensional linear encoder sensor of the aforementioned PP271R and PP281R of HEIDENHAIN, Germany Etc. are used.
The high-precision gap sensor 10 is provided on the upper surface of the movable table 3, and the target 11 is disposed on the fixed table 2 facing the high-precision gap sensor 10.
The low-accuracy gap sensor 12 is installed on the fixed base 2, and the target 13 is disposed on the movable base 3 that faces the low-precision gap sensor 12.
Two rotation detection gap sensors 14 are arranged at a distance from the fixed base 2, and a target 13 having a length corresponding to the Y-axis stroke is arranged on the opposed movable base 3. The target 13 is also used for the low precision gap sensor 12.
Next, the detailed structure of the levitating electromagnet 4 and the levitating magnetic piece 17 will be described. The levitation electromagnet 4 and the levitation magnetic piece 17 are arranged as shown in FIG. One or both of the levitation electromagnet 4 and the levitation magnetic piece 17 are covered with a nonmagnetic material 20 made of a resin material such as PTFE, a metal material such as stainless steel, and the like, and the opposing gap has a high-precision gap. It is formed to be smaller than the distance between the sensor 10 and the target 11.
JP 2002-261000 A (page 10, FIG. 1) JP 2006-287033 A

A precision stage used in a conventional projection exposure apparatus is required to be positioned with high accuracy in order to transfer a circuit board of a semiconductor integrated circuit or a liquid crystal substrate onto a photosensitive substrate. As the line width to be transferred becomes finer, not only the accuracy required for the stage but also the positioning is required for the attitude control as well as the positioning. In such a situation, it is necessary to control the exact position and orientation by detecting the vicinity of the conveyed object with the position detection unit.
However, in the conventional stage apparatus, miniaturization and precise positioning performance are required. However, if a laser interferometer or the like is used for measuring the position of the object to be conveyed in order to realize precise positioning, the light will be lost. In order to secure a space through which the shaft passes, there has been a problem that the stage device is enlarged. Furthermore, since the stage device is increased in size, the drive current is increased, so that thermal expansion due to heat generation occurs in the mechanical components, resulting in a problem that traveling performance and posture accuracy are deteriorated.
In addition, since the position of the center of gravity of the movable table is not directly detected, for example, the value including the shape error, deflection and distortion of the movable table is measured, so that the accurate position and posture of the movable table are measured. Therefore, even if the position and orientation are controlled, there is a problem that the movable base cannot be controlled accurately.
Therefore, the present invention provides a stage device that can be downsized and capable of stable levitation control without lowering the running performance and posture accuracy, a driving method thereof, and an exposure apparatus using the stage device. It is intended.

In order to solve the above problem, the present invention is configured as follows.
The invention according to claim 1 is a fixed base having a levitation electromagnet arranged so as to face the movable base at least three by three, a movable base supported by the non-contact magnetic levitation method by the levitation electromagnet, A floating sensor gap sensor provided in the movable table; a two-dimensional linear sensor disposed in the center of the movable table; and a linear motor that drives the movable table; A plurality of optical measuring means for detecting the position and a low-accuracy gap sensor are provided so that the optical axis of the light source of the optical measuring means passes through the fixed base so as to measure the displacement in one direction of the movable base. And an opening corresponding to the amount of displacement in a direction orthogonal to the direction measured by the movable table is formed so as to communicate with a reflection mirror provided near the center of gravity .
According to a second aspect of the present invention, in order to measure the displacement of the movable table in the X-axis direction, an opening is formed on one surface of the fixed table and the movable table parallel to the moving direction of the movable table in the Y-axis direction. It is equipped with.
The invention according to claim 3 is the invention according to claim 4, wherein the opening of the movable table is formed larger in the moving direction in the Y-axis direction of the movable table than the opening of the fixed table. The said opening part of the said movable stand is formed in the symmetrical structure with respect to the said gravity center position of the said movable part.
According to a fifth aspect of the present invention, a reflection mirror of the optical measuring means is provided in the vicinity of the center of gravity of the movable table.
The invention according to claim 6 is the stage apparatus, wherein the object to be conveyed is positioned by the stage apparatus.

According to the present invention, since the fixing base is provided with the hole through which the optical path of the optical measuring instrument is communicated, the optical path is not separately provided, so that the stage apparatus is miniaturized. By reducing the size, the amount of heat generated by the linear motor for driving is reduced, and the thermal performance is suppressed by suppressing thermal expansion.
In addition, the levitation electromagnet and the levitation magnetic piece of the levitation force are applied so that the relative relationship between the point of application of the levitation force acting on the movable table and the center of gravity of the movable table and the generated levitation force are constant regardless of the movement position of the movable table. Since the shape is formed, controllability is improved because the flying height of the movable table is always constant even if the position of the movable table changes. Further, by switching the gap sensor according to the flying height, the flying control can be performed in a wide range, and the flying control with high accuracy can be performed.
In addition, the controllability is improved because the relative relationship between the operating point of the driving force acting on the movable table and the center of gravity of the movable table and the generated driving force are controlled to be constant regardless of the moving position of the movable table. To do. Further, by switching the linear sensor at the time of positioning, the movement amount can be controlled in a wide range, and highly accurate positioning control can be performed.
Further , an exposure operation can be performed by a stage apparatus in which the movable table is supported in a non-contact manner.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Since the embodiment of the present invention is an improved invention with respect to Patent Document 2, description of the configuration of the same reference numerals as those of the prior art described in Patent Document 2 is omitted. FIG. 1A is a top view of the stage apparatus of the present invention, and FIG. 1B is a side view as seen from the Y-axis direction.
The stage 1 includes a levitation electromagnet 4, a Y-axis linear motor 5, an X-axis linear motor 6, a fixed base 2 including a two-dimensional linear sensor 8, the Y-axis linear motor 5 and the X-axis linear motor 6. The movable table 3 is positioned.
The fixing base 2 has a substantially rectangular shape with both ends in the Y-axis direction open and a groove-like opening extending in the Y-axis direction on the lower surface, and a hole 9 is provided in the top plate. The hole 9 penetrates along the optical axis in order to pass the optical axis of the Z-axis optical measuring instrument 51 that measures the position of the movable table 3 or the transported object 15.
Further, the fixed base 2 is provided with a side surface of one side of the fixed base 2 parallel to the Y-axis traveling direction so that the position of the movable base 3 in the X direction is measured, and the opening 56 is an X-axis optical type. The measuring instrument 52 is formed with a size that allows the optical axis of the measuring instrument 52 to pass. In order to measure the vicinity of the center of gravity of the movable table 3, the movable table 3 is also provided with an opening 57 in the same direction as the side where the opening 56 of the fixed table 2 is provided, and the opening 57 is movable table 2 in the Y-axis direction. It is formed in a size corresponding to the amount of movement. A reflection mirror 54 of an optical measuring instrument is provided near the center of gravity of the movable table 3. The movable table 3 may be provided with the opening 57 in the same direction as one side where the opening 56 of the fixed table 2 is provided in order to measure the position in the X direction. In order to make it the center, it is good also as a symmetrical structure with respect to the advancing direction of the movable stand 3. FIG.
In addition, a reflection mirror 55 is provided in the Y direction of the movable table 3 and reflects the light from the Y axis optical measuring instrument 53 to measure the position in the Y axis direction.
The fixed base 2 includes two sets of Y-axis linear motors 5 and one set of X-axis linear motors 6 arranged in parallel to each other. In addition, the levitation electromagnet 4, the Y-axis linear motor 5 and the stator 51 of the X-axis linear motor 6 are arranged vertically symmetrically on the top and bottom plates of the fixed base 2, and the levitation electromagnet 4 is divided into four parts. As shown to Fig.1 (a), it arrange | positions at intervals and avoiding an optical axis.
The optical measuring instrument used here has a short wavelength such as a laser length measuring instrument.

Next, the operation will be described. The rotation detection gap sensor 14 measures the position of the movable table 3 in the X direction, and the inclination of the movable table 3 with respect to the fixed table 2 is obtained from the difference value between the two sensor 14 signals. When the movable table 3 has an inclination greater than the allowable relative angle of the two-dimensional linear sensor 8 as shown in FIG. 2A, the movable table 3 is fixed as shown in FIG. Movable by pressing the movable base 3 with a linear motion actuator 18 composed of a ball screw mechanism or the like arranged at a distance from the base 2 and pressing against two positioning blocks 19 provided in the opposite direction of the fixed base 2 The base 3 is made parallel to the fixed base 2.
Next, the movable table 3 is lifted from the landing position to the measurement range of the Z-axis optical measuring instrument 51 based on the detection signal of the low precision gap sensor 12. Next, the movable table 3 is controlled to float based on the detection signal of the optical measuring instrument 51 for the Z axis.
Next, the movable base 3 is driven by the X-axis linear motor 6 and the Y-axis linear motor 5 based on the position signal of the two-dimensional linear sensor 8, and the X-axis optical measuring instrument 52 and the Y-axis optical measuring instrument 53 When entering the measurement range, the sensor signal to the control device (not shown) is switched, and the conveyed object 15 is positioned at the target position.

The present invention differs from Patent Documents 1 and 2 in that an opening is provided on one side parallel to the movement direction of the fixed base and the movable base in the Y-axis direction, and the optical axis of the optical measuring instrument is in the vicinity of the center of gravity of the movable base. It is a point introduced in. With such a configuration, the stage device is reduced in size, the amount of heat generation is reduced, and the thermal expansion is suppressed, so that traveling performance and posture accuracy are improved.
Moreover, controllability is improved by measuring the vicinity of the center of gravity of the movable table along all three axes of X, Y, and Z, and traveling performance and posture accuracy are improved.

FIG. 3 is a view of an exposure apparatus provided with the stage apparatus of the present invention. Reference numeral 31 denotes an exposure apparatus, and reference numeral 32 denotes a vacuum chamber that houses the exposure apparatus 31. A light source 33 emits EUV light having a wavelength of 0.1 to 400 nm. Reference numeral 34 denotes a stage device, which is one of the two-axis positioning devices described in the first to third embodiments. A mask 35 is attached to the lower surface of the stage device 34. A pattern of a circuit formed on the wafer 36 is drawn on the mask 35. The wafer 36 is placed on the wafer stage 37.
The EUV light emitted from the light source 33 is collected by the condenser mirror 38, reflected by the mask 35, and repeatedly reflected in the order of the concave mirror 39, the concave mirrors 40 and 41, and the concave mirror 37, and reaches the wafer 36. In addition, the stage device 34 and the wafer stage 37 move in phase with each other so that a reduced image of the circuit pattern drawn on the mask 35 is formed on the surface of the wafer 36.

  INDUSTRIAL APPLICABILITY The present invention is useful as a stage device that freely positions an object in a plane in the field of semiconductor manufacturing or the like.

The top view and side sectional view of the stage apparatus which show the Example of this invention Top view showing the operation of the movable table rotation angle adjustment mechanism The figure of the exposure apparatus provided with the stage apparatus of this invention It is a perspective view of the stage apparatus which shows the conventional 1st invention. It is the top view and side sectional view of the stage apparatus which show the conventional 2nd invention. Sectional drawing which shows the structure of the electromagnet for levitation | floating of the conventional 2nd invention, and the magnetic piece for levitation | floating

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stage device 2 Fixed base 3 Movable base 4 Levitation electromagnet 5 Y-axis linear motor 6 X-axis linear motor 7 Two-dimensional linear scale 8 Two-dimensional linear sensor 9 Optical axis hole 10 High-precision gap sensor 11 Target 12 Low-precision gap sensor 13 Target 14 Rotation detection gap sensor 15 Object 16 Optical axis hole 17 Levitation magnetic piece 18 Linear actuator 19 Positioning block 20 Nonmagnetic material 21 Piezo actuator 22 Rod 23 Support point 24 Piezo actuator 25 Rod 26 Elevating mechanism 27 Elevating mechanism Mechanism 28 Roller 29 Roller support 30 Support base 31 Exposure device 32 Vacuum chamber 33 Light source 34 Stage device 35 Mask 36 Wafer 37 Wafer stage 38 Condensing mirror 39 Concave mirror 40 Convex mirror 41 Convex mirror 42 Concave mirror 100 Stage device 101 Fixed frame 102 Slider 103 Support platform 104 Support platform 105 X linear motor 106 Y linear motor

Claims (6)

A fixed base provided with at least three levitation electromagnets arranged to face the movable base, a movable base supported by the non-contact magnetic levitation method with the levitation electromagnet, and a levitation provided in the movable base A plurality of optical systems that include a gap sensor for control, a two-dimensional linear sensor disposed in the center of the movable table, and a linear motor that drives the movable table, and detects a position near the center of gravity of the movable table. A measuring means and a low-accuracy gap sensor, and an opening corresponding to the size of the optical axis of the light source of the optical measuring means passing through the fixed base so as to measure the displacement in one direction of the movable base; A stage device characterized in that an opening corresponding to a displacement amount in a direction orthogonal to a direction measured by the movable table is formed so as to communicate with a reflection mirror provided in the vicinity of the center of gravity . The opening is provided on one surface of the fixed base and the movable base parallel to the moving direction of the movable base in the Y-axis direction in order to measure the displacement of the movable base in the X-axis direction. The stage apparatus according to 1. 3. The stage device according to claim 1, wherein the opening of the movable table is formed larger in the movement direction of the movable table in the Y-axis direction than the opening of the fixed table. The stage apparatus according to claim 1, wherein the opening of the movable base is formed in a symmetric structure with respect to the position of the center of gravity of the movable part. The stage apparatus according to claim 1, wherein a reflection mirror of the optical measuring unit is provided in the vicinity of the center of gravity of the movable table. 6. The exposure apparatus according to claim 1, wherein an object to be conveyed is positioned by the stage apparatus.

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