JP2007053244A - Stage equipment and its exposure device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stage equipment which allows precision rising/positioning as well as quick rising even from such state as a movable stage is rotated in two-dimensional plane. <P>SOLUTION: In the stage equipment 1, a movable stage 3 is supported by an electromagnet 4 for levitation movable in mutually orthogonal two axial directions against a stationary base 2. The movable stage 3 is driven by a Y-axis linear motor 5 and X-axis linear motors 6a and 6b for positioning. Even if the movable stage supported by non-contact manner is rotated in the two-dimensional plane when not raised, the movable stage is corrected for rotation by the X-axis linear motors 6a and 6b that are attached to it for driving it based on rotational angle sensor signals after rising, allowing a positioning linear encoder of the movable stage for detection. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a stage apparatus that is positioned at an arbitrary position in a state where a movable table is supported in a non-contact manner, and an exposure apparatus that uses this stage apparatus, and more particularly to a sensor that detects the parallelism of a stage.

  Conventionally, a projection exposure apparatus has been proposed in order to transfer a semiconductor integrated circuit or a circuit board of a liquid crystal substrate onto a photosensitive substrate (for example, see Patent Document 1).

In recent years, miniaturization of a mask pattern has progressed, and a stage apparatus used therein has been required to have more precise positioning performance. As a stage device satisfying such precise positioning performance, there is one proposed by the present applicants (Japanese Patent Application No. 2005-106214).
FIGS. 8A and 8B are views showing this stage apparatus, where FIG. 8A is a top view of the stage apparatus, and FIG. 8B is a side view of the stage apparatus as seen from the Y-axis direction.
In the figure, 1 is a stage device, 2 is a fixed base, 3 is a movable base, 4 is a levitation electromagnet, 5 is a Y-axis linear motor, 6 is an X-axis linear motor, and 8 is a two-dimensional linear sensor.
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 fixed 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 through-inclined hole 9 is provided in the top plate. . The through-inclination hole 9 is inclined and penetrates along the optical axis in order to pass the optical axis of the optical measuring instrument that 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 arranged in parallel to each other and two sets of X-axis linear motors 6 arranged at a predetermined interval on one side.
Further, the top plate 2a and the bottom plate 2b of the fixed base 2 are arranged with levitation electromagnets 4, Y-axis linear motors 5 and X-axis linear motor 6 stators symmetrically vertically, and at least three levitation electromagnets 4, In FIG. 8A, it is divided into four parts and spaced apart from each other so as to avoid the 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, on the upper surface and the lower surface of the movable table 3, the movers of the floating magnetic piece 17, the Y-axis linear motor 5 and the X-axis linear motor 6 are arranged. 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 example, 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. Yes.
Two two-dimensional linear sensors 8 are attached to the fixed base 2 at a predetermined interval in the Y direction (the direction perpendicular to the paper surface in FIG. 8B). 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 low-accuracy gap sensor 12 is installed on the fixed base 2 and is used when starting up the apparatus. A target 13 (used as both a low accuracy gap sensor and a rotation detection gap sensor) facing the low accuracy gap sensor 12 is disposed on the movable table 3.
The high-accuracy gap sensor 10 is provided on the upper surface of the movable table 3 and is used for levitation control after the apparatus is started up. A target 11 facing the high-precision gap sensor 10 is arranged on the fixed base 2.

As described above, in the case of a stage supported by a non-contact bearing, the restraint of the movable table 3 is released at the time of non-levitation, so that the movable table 3 may rotate in a two-dimensional plane with respect to the fixed table 2. There is. Even if the movable base 3 is rotated in a two-dimensional plane, the scale 7 and the sensor 8 of the two-dimensional linear encoder for obtaining the positions in the X-axis direction and the Y-axis direction are not within the allowable azimuth angle range. Therefore, encoder information cannot be read after ascending, and positioning control in the X and Y directions cannot be performed. Therefore, it is necessary to provide a movable table parallelizing mechanism for correcting the rotation after the movable table 3 is lifted and making it parallel to the fixed table 2.
The movable table parallelizing mechanism will be described with reference to FIGS. The rotation detection gap sensor 14 measures the position of the movable table 3 in the X direction, and obtains the inclination of the movable table 3 in the X direction with respect to the fixed table 2 from the difference value between the signals of the two sensors 14. 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. 9A, the movable table 3 is arranged at a distance from each other. As shown in FIG. 9B, the linear actuators 18 are pushed toward the movable table 3 by the pushers 18 a, and the movable table 3 is pressed against the two positioning blocks 19 provided in the opposite direction of the fixed table 2. Thus, the movable table 3 can be made parallel to the fixed table 2.
JP 2002-261000 A

However, the conventional movable base collimating mechanism requires the mounting of components such as the rotation detection gap sensor 14, the target 13 for the rotation detection gap sensor, and the linear actuator 18, which hinders downsizing of the apparatus. It was. In particular, when the stroke of the X axis is long, the outer dimension of the rotation detection gap sensor 14 becomes large, making it difficult to reduce the size of the apparatus.
Therefore, the present invention has been made in view of such problems, and by providing a sensor that can detect a rotation angle of a plane and detect only a gap necessary for magnetic levitation control, it has a simple structure and is small and highly accurate. An object of the present invention is to provide a stage apparatus and an exposure apparatus using the stage apparatus.

In order to solve the above problems, the present invention is configured as follows.
The invention according to claim 1 relates to a stage apparatus, and has a substantially rectangular shape with both ends in a uniaxial direction on a two-dimensional plane open and a groove-like opening extending in the axial direction on a lower surface and floated. A fixed base provided with an electromagnet for operation, a movable base provided with a floating magnet piece acting on the floating electromagnet and supported in the opening of the fixed base by a non-contact magnetic levitation method, and the movable base A stage device comprising: a two-dimensional linear sensor disposed in the center of the sensor; and a linear motor that controls and drives the movable table in a two-dimensional plane based on a detection signal of the two-dimensional linear sensor.
A magnetic slit plate having a slit length longer than the stroke length in the X-axis direction is provided at a predetermined interval with respect to the center line of the movable table in the Y-axis direction of the long stroke of the two-dimensional plane on which the movable table moves. Two parallel sensors are arranged, and a magnetic sensor that generates a two-phase sine wave signal having a phase of 90 degrees is opposed to the magnetic slit plate, and is arranged in the vicinity of the stroke center. Is provided with a rotation angle detection sensor for measuring the rotation angle in the two-dimensional plane.
According to a second aspect of the present invention, the rotation angle of the movable table is obtained by phase-modulating a two-phase signal having a phase of 90 degrees of the magnetic sensor, and obtaining the phase difference between the phase modulation signals of the sensor signals arranged at both ends, The rotational angle of the movable table in a two-dimensional plane is corrected by controlling the thrust of linear motors provided at both ends of the movable table based on the rotation angle signal.
The invention according to claim 3 relates to an exposure apparatus, wherein a light source, an optical system for reflecting and condensing light from the light source, and a mask stage apparatus capable of attaching a mask to the lower surface in a vacuum chamber, In an exposure apparatus comprising a wafer stage, and moving the stage apparatus and the wafer stage relatively to form a reduced image of a circuit pattern drawn on the mask on the wafer, the mask stage apparatus comprises: The stage apparatus according to claim 1 or 2 is provided.

According to the first and second aspects of the present invention, even if the movable table supported by the non-contact bearing rotates in a two-dimensional plane when not levitating, first, the movable table is based on the rotation angle signal of the movable table. Is rotated by a linear motor that drives in the X-axis direction and the Y-axis direction, and is then switched to position control by encoder signals used for precise positioning in the X-axis direction and Y-axis direction, so that the apparatus can be started up quickly. it can.
Since there is no need to add a mechanism for correcting and collimating the movable table before or after the movable table is levitated, the stage can be reduced in size.
According to the third aspect of the present invention, an exposure apparatus having a simple structure, a small size, and high accuracy can be obtained by the 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.

FIG. 1 is a top view and a side sectional view of a stage apparatus showing a sensor arrangement for detecting a rotation angle of a movable table 3 according to the present invention.
In the figure, 6, 6a, 6b are X-axis linear motors, 20, 20a, 20b are rotation angle detection sensor heads, and 21, 21a, 21b are magnetic slit plates. Other symbols are the same as in the conventional example.
Two rotation angle detection sensor heads 20a and 20b are arranged on the fixed base 2 at a predetermined interval in the X-axis direction (horizontal direction in FIG. 1B). On the movable table 3, magnetic slit plates 21a and 21b shown in FIG. 23 having a slit length longer than the stroke length in the X-axis direction and a slit pitch interval P in the Y-axis direction are provided in a predetermined manner. The rotation angle detection sensor heads 20a and 20b that are installed at an interval are mounted on the fixed base 3 so as to face each other. The rotation angle detection sensor heads 20a and 20b and the magnetic slit plates 21a and 21b are arranged to face each other with a gap of several hundred microns to several millimeters. The magnetic slit plates 21a and 21b are manufactured by forming slits in a magnetic material such as a silicon steel plate, for example, by a processing technique such as etching.
As shown in FIG. 3, the rotation angle detection sensor head 20 comprises a magnetic sensor comprising MR elements 23 to 26, a bias magnet 27 for generating a bias magnetic flux, and a basic detection circuit shown in FIG. Then, the resistance change of the MR elements 23 to 26 is converted into a voltage signal. The MR elements 23 to 26 are arranged in each magnetic sensor head at a pitch interval of P / 4 where P is the pitch interval of the slits 22 of the magnetic slit plate 21. FIG. 5 shows a signal processing circuit for obtaining a rotation angle in response to signals from the rotation angle detection sensor heads 20a and 20b.
The principle of detecting the rotation angle of the movable table 3 will be described. When the movable table 3 travels, the slits 22 of the slit magnetic plates 21a and 21b pass under the rotation angle detection sensor heads 20a and 20b in FIG. The value changes. This resistance change is converted into an A-phase and B-phase sine wave signal having a phase difference of 90 degrees by the basic detection circuit of FIG. Each signal is phase-modulated by the phase modulation circuits 28a and 28b. Here, the phase modulation means that the amount of slit displacement due to the movement of the magnetic slit is x, and the A phase signal V _A and the B phase signal V _B are respectively
V _A = V ₀ sin (2π · x / P) (1)
V _B = V ₀ cos (2π x / P) (2)
And when, which respectively summed amplitude balanced modulated with V ₁ angular frequency _{ω t (2π · x / P} << ω t) of the carrier V ₁ sin .omega _t, with V ₁ cos .omega _t, the modulated signal S can be expressed as:
S ＝ V ₀ V ₁ sin (2π ・ x / P) sinω _t + V ₀ V ₁ cos (2π ・ x / P) cosω _{t
= (V 0 V 1/2} ) {(cos (ω t -2π · x / P) -cos (ω t + 2π · x / P)
+ Cos (ω _t −2π · x / P) + cos (ω _t + 2π · x / P))
＝ V ₀ V ₁ cos (ω _t −2π ・ x / P) (3)
Ie, A-phase, if the addition was balanced modulation with the carrier of the angular frequency omega _t a voltage signal of the B phase signal, will be when x displacement modulated signal S phase changes by 2 [pi · x / P, the magnetic The slit displacement information can be converted into a phase signal.
For example, as shown in FIG. 6, when the movable table 3 rotates on a two-dimensional plane, a phase difference is generated between the outputs of the two rotation angle detection sensor heads 20a and 20b. When the phase of the phase modulation signal S obtained from the rotation angle detection sensor head 20a is compared with the phase of the phase modulation signal S obtained from the rotation angle detection sensor head 20b, the rotation angle of the movable table 3 can be obtained from the phase change. When the movable table 3 is not rotated on a two-dimensional plane, no phase difference occurs.
The rotation angle of the movable table 3 on a two-dimensional plane is detected, and the rotation angle of the movable table 3 is determined by two sets of X-axis linear motors 6a and 6b mounted on the movable table 3 based on the rotation angle information. The scale 7 and the sensor 8 of the linear encoder that corrects and measures the position in the X direction and the Y direction can be adjusted to the allowable azimuth angle range.

FIG. 7 is an explanatory view of an exposure apparatus showing Embodiment 2 of the present invention.
In the figure, reference numeral 31 denotes an exposure apparatus, and 32 denotes a vacuum chamber in which the exposure apparatus 31 is accommodated. A light source 33 emits EUV light having a wavelength of 0.1 to 400 nm. Reference numeral 34 denotes a mask stage device, which is the biaxial positioning device described in the first embodiment. A mask 35 is attached to the lower surface of the mask 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, convex mirrors 40 and 41, and concave mirror 42 to reach the wafer 36. Further, the mask stage device 34 and the wafer stage 37 move in phase with each other so as to form a reduced image of the circuit pattern drawn on the mask 35 on the surface of the wafer 36.

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

It is the upper side figure and side sectional view of a stage apparatus which show Example 1 of this invention. It is an enlarged plan view which shows the magnetic body slit board of FIG. FIG. 2 is an enlarged plan view showing the rotation angle detection head of FIG. 1. It is explanatory drawing which shows the basic detection circuit of the rotation angle detection head which concerns on this invention. It is a block diagram which shows the signal processing circuit of the rotation angle detection which concerns on this invention. It is a top view which shows the sensor arrangement | positioning figure which concerns on this invention. It is a principle figure of the exposure apparatus provided with the stage apparatus which shows Example 2 of this invention. It is the upper side figure and side sectional view which show the conventional stage apparatus. It is a top view which shows the rotation detection operation | movement of the conventional stage apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stage apparatus 2 Fixed base 3 Movable base 4 Levitation electromagnet 5 Y-axis linear motor 6, 6a, 6b X-axis linear motor 7 Two-dimensional linear scale 8 Two-dimensional linear sensor 9 Through inclined hole 10 High precision gap sensor 11 Target (High) (For accuracy gap sensor)
12 Low accuracy gap sensor 13 Target (for both low accuracy gap sensor and rotation detection gap sensor)
14 Rotation detection gap sensor 15 Transported object 16 Optical axis hole 17 Levitation magnetic piece 18 Linear motion actuator 18a Pusher 19 Positioning blocks 20, 20a, 20b Rotation angle detection sensor heads 21, 21a, 21b Magnetic slit plate 22 Slit ( Magnetic slit plate)
23, 24, 25, 26 MR element 27 Bias magnet 28, 28a, 28b Phase modulation circuit 29 Phase difference detection circuit 31 Exposure device 32 Vacuum chamber 33 Light source 34 Mask stage device 35 Mask 36 Wafer 37 Wafer stage 38 Condensing mirror 39 Concave surface Mirrors 40, 41 Convex mirror 42 Concave mirror

Claims (3)

A fixed base having a substantially rectangular shape having both ends in one axial direction of a two-dimensional plane and a groove-like opening extending in the axial direction on the lower surface, and a floating electromagnet disposed thereon; A movable base provided with a floating magnet piece acting on the electromagnet and supported in the opening of the fixed base by a non-contact magnetic levitation method; a two-dimensional linear sensor disposed in the center of the movable base; A stage device comprising: a linear motor that controls and drives the movable table in a two-dimensional plane based on a detection signal of a two-dimensional linear sensor;
A magnetic slit plate having a slit length longer than the stroke length in the X-axis direction is provided at a predetermined interval with respect to the center line of the movable table in the Y-axis direction of the long stroke of the two-dimensional plane on which the movable table moves. Two parallel sensors are arranged, and a magnetic sensor that generates a two-phase sine wave signal having a phase of 90 degrees is opposed to the magnetic slit plate, and is arranged in the vicinity of the stroke center. A stage device provided with a rotation angle detection sensor for measuring a rotation angle in a two-dimensional plane.   The rotation angle of the movable base is obtained by phase-modulating a two-phase signal having a phase of 90 degrees of the magnetic sensor, and obtaining from the phase difference between the phase modulation signals of the sensor signals arranged at both ends, and based on the signal of the rotation angle. 2. The stage apparatus according to claim 1, wherein a rotation angle of the movable table in a two-dimensional plane is corrected by controlling a thrust of a linear motor provided at both ends of the movable table. The vacuum chamber includes a light source, an optical system that reflects and collects light from the light source, a mask stage device that can attach a mask to a lower surface, and a wafer stage on which a wafer is placed, and the stage An exposure apparatus that relatively moves the apparatus and the wafer stage to form a reduced image of the circuit pattern drawn on the mask on the wafer;
An exposure apparatus comprising the stage apparatus according to claim 1 or 2.

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