JPH04134293A - Positioning device - Google Patents

Abstract

PURPOSE:To shorten the time for positioning and suppress secular change of the vibration suppressing performance by inserting high viscosity Si oil or the like to between a Z-stage and a base board. CONSTITUTION:A Z-stage is tiltable to any direction (rotating round X-axis and Y-axis) and also movable in the Z-direction. A damping means comprises pistons 10a-10c secured to this Z-stage 3, cylinders 11a-11c fixed to a base board 6 in such a way as enwrapping these pistons, and Si oil 12a-12c having a high viscosity. Thereby vibrations of the Z-stage are damped and stopped only by pure viscosity resistance, and the time for positioning can be shortened. Because Si oil is very stable and less evaporative, the vibration suppressing performance is free from secular change substantially.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an exposure apparatus, an NC machine tool, and various measuring instruments for manufacturing semiconductor integrated circuits, and in particular, the present invention relates to an exposure apparatus, an NC machine tool, and various measuring instruments for manufacturing semiconductor integrated circuits, and in particular, a flat object is placed and tilted to measure the precision of a predetermined reference surface. The present invention relates to a positioning device that aligns the surface of a flat object with the surface of a flat object.

[Prior Art] A ZTi°Ct stage (two-tilt stage, hereinafter referred to as Z stage) of a conventional semiconductor exposure apparatus is shown in FIG. 3.4.

The projection lens 1 forms a projected image of a circuit pattern drawn on a reticle (original plate) (not shown) on a predetermined exposure reference plane, that is, an image plane. A wafer 2 to be exposed is held on a Z stage 3 via a chuck 4. One end of the leaf spring 5a is fixed to a leaf spring stand 7a fixed to the base 6, and the other end is fixed to the two stages 3. 5a to 5c and 7a to 7c constitute a Z stage 3 kite. The driving means consists of piezos 8a to 8C that extend and contract in the Z direction, and one end of each piezo is fixed to the base, and the other end is in contact with the two stages via a pole.

The piezos 8a to 8 are controlled by a second detector 9 that detects a height deviation and a tilt deviation between the image plane and the surface of the wafer 2, and a control device (not shown).
c to align the image plane with the wafer surface. At this time, the second stage 3 vibrates at a mechanical resonance frequency determined by the stiffness of the piezo, the weight of the Z stage, the stiffness of the plate springs, etc., prolonging the positioning time. A damper is installed to prevent this. In this tamper, a damping rubber 15a is sandwiched between an L angle 13a fixed to the second stage and an angle 14a fixed to the base 6, and a preload is applied to the damping rubber by preload ports I to 17a via a plate 16a. It is a configuration that gives. With this configuration, the vibrations of the two stages can be quickly absorbed and the positioning time can be shortened.

[Problems to be Solved by the Invention] However, in the conventional example described above, the damping rubber gradually deteriorated, and manufacturing irregularities were relatively large, so the stability of the damping performance was poor. Furthermore, since a force is generated to press the Z stage downward, the initial position of the Z stage (for example, a state in which CMv is applied to the piezo) changes depending on the preload force. It also changes due to deterioration of the damping rubber. In this way, the initial position of the Z stage changed over time and had to be readjusted.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide a positioning device that suppresses changes in the initial position over time and has stable vibration damping properties.

[Means and effects for solving the problem] In order to achieve the above object, according to the present invention, high viscosity silicone oil or the like is inserted between the Z stage and the base as a two-stage vibration damping means. To shorten positioning time and to minimize changes in damper performance over time. Also 2
Since no external force is applied to the stem, its initial position does not change over time.

[Embodiment] FIGS. 1 and 2 are a plan view and a vertical sectional view of an embodiment of the present invention, respectively.

The projection lens 1 forms a projected image of a circuit button drawn on a reticle on a predetermined exposure reference plane, that is, an image plane.

A wafer 2 to be exposed is held on a Z stage 3 via a chuck 4. One end of the plate spring 5a is fixed to a plate spring stand 7a fixed to the base 6, and the other end is fixed to the Z stage 3. The fixed point of the two stages 3 to the leaf spring 5a can be elastically deformed in two directions, but is not displaced at all in the X and Y directions. Other leaf springs 5b, 5c and leaf spring stand 7b
, 7c as well. These constitute a 2-stage 3 guide. The driving means consists of piezos 8a to 8c that expand and contract in the Z direction, and one end of each piezo is fixed to the base, and the other end contacts and supports the Z stage via a steel ball.

With this configuration, the two stages can be tilted in any direction (rotation around the X axis and rotation around the Y axis) and can also move in the Z direction. The piezos 8a to 8c are driven by a second detector 9 that detects a height deviation and a tilt deviation between the image plane and the wafer surface and a control device (not shown) to align the image plane and the wafer surface. Damper means for absorbing vibrations during positioning are pistons 10a to 10c fixed to the two stages 3.
The cylinders 11a to 11c are fixed to the base 6 so as to enclose these pistons, and high viscosity silicone oils 12a to 12c are filled in each cylinder. As a result, the vibrations of the two stages are attenuated and stopped only by pure viscous resistance, which greatly reduces the positioning time. At this time, only the force for damping vibration acts on the second stage 3 and no other external force acts on it, so the initial position of the second stage 3 is not changed or the Z stage itself is not deformed.

Furthermore, silicone oil is very stable and evaporates very little, so there is almost no change in damping performance over time. In addition, the viscous resistance can be easily increased by increasing the amount of silicone oil, reducing the gap between the piston and cylinder, or using silicone oil with a higher viscosity.

Note that the same effect can be obtained by using a magnetic fluid instead of the high viscosity silicone oil of the damper.

[Effects of the Invention] As explained above, by using only the viscous resistance of high-viscosity silicone oil or the like to damp the vibration of the Z stage, it is possible to shorten the positioning time and keep the change in vibration damping performance to a very small level over time. I can do it. Also, an external force (
Since no preload force is applied, the posture stability of the Z stage itself increases over time.

[Brief explanation of drawings]

FIG. 1 is a plan view of an embodiment of the present invention; Figure 2 is a longitudinal sectional view of Figure 1; Figure 3 is a plan view of the conventional example; FIG. 4 is a longitudinal sectional view of FIG. 3. into the projection lens, 2. Wafer, 3 Z stage, 4 Chuck, 58~5C8 plate blade, 6. Foundation, ω～tsu size Q　B O a~7c board board stand, a~8C Viniso, 2 detectors, Oa~10c 1 a ~ 11 C 2a-12c 3a-13c 4a-14c: 5a-15c 6a-16c 7a-17c piston, Syringe, high viscosity silicone oil, L angle, L angle, vibration damping rubber, board, Preload Holt.

Claims (3)

[Claims] (1) A stage on which a flat object to be positioned is mounted, a position detection means for detecting the height and inclination of the flat object with respect to a predetermined reference plane, and a position adjustment means for displacing the height and inclination. a base for movably supporting the stage; a control means for driving the position adjusting means based on the detection result of the position detecting means; and a piston cylinder made of only viscous fluid interposed between the stage and the base. A positioning device characterized by comprising a type of damper means. (2) The positioning device according to claim 1, wherein the position adjustment means comprises piezo elements that abut three locations on the stage and are each driven independently. (3) The positioning device according to claim 1, wherein the viscous fluid is made of silicone oil.