JPS61284352A - Fine feed stage using piezo-electric actuator - Google Patents

Abstract

PURPOSE:To enlarge a displacement by several to several ten times for practical use by combining a piezo-electric actuator and a buckling spring to enlarge the actuator produced displacement by the buckling spring. CONSTITUTION:A stage 1 is provided in the conters between both sides with projections 9 for receiving springs to be pressed from both sides by leaf springs 4, 5. The spring 5 is fixedly embedded in a frame 2 on one end and compressed on the other end by a headless screw. The frame 2 is also provided with projections opposed to those on the stage 1 and the leaf springs 4, 5 are sandwiched between the projections. Also, since the leaf springs are pressed by said projections on the frame 2 to be always warped, the spring 5 is subjected to the buckling defromation by tightening a screw 8 to move the stage 1 to the right side. When voltage is applied to an actuator 6, the leaf spring 4 is buckled and deformed according to the the size of applied voltage to push back the stage 1 to the left side. The relationship between the applied voltage and piezo-electric actuator 6 displacement is shown by the saturation curve while, more linearity relationship is maintained by utilizing the balance of springs.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1 Object of the Invention] The present invention relates to an improvement of a fine movement stage, and is a stage that finely moves a piezoelectric actuator with a drive element. The purpose of this invention is to provide a fine movement stage that takes advantage of the piezoelectric actuator's features of a simple, robust, and compact movement mechanism, and that also has a significantly lower driving voltage.

[Technology background]

Recent dramatic advances in the semiconductor industry have encouraged the advancement of ultra-fine technology, and ultra-fine technology is also advancing the semiconductor industry.

Under these circumstances, submicron positioning accuracy is required for mask alignment in tSr and vL-s processes, electron microscopes for device observation, etc., and piezoelectric actuators that accurately control minute displacements have been used.

[Conventional technology]

Piezoelectric actuators are attracting attention as precision positioning elements due to their simple structure, robustness, and miniaturization.
The fact that it required a high voltage of about 1,000 volts was a fatal flaw in practical use.

In this respect, the stacked actuator, which focuses on low voltage, is noteworthy, but the displacement rate of an actuator with a length of 10++wn50 layers is about 1 μm/50 V.

The disadvantage is that the maximum limit stroke is 4 μm/200 V, and the amount of displacement is still one order of magnitude smaller than the desired amount in practice.

[Means for solving problems]

This invention solves the above-mentioned drawbacks of the prior art.
As a means for moving a fine movement stage driven by a piezoelectric actuator, the fine movement stage is characterized in that the piezoelectric actuator and a buckling spring are combined, and the displacement created by the actuator is expanded by the buckling spring. The purpose has been achieved.

Embodiments of the present invention will be described below with reference to the drawings.

〔Example〕

Embodiment 1 FIG. 1 is a principle explanatory diagram showing an embodiment of a fine movement stage using a piezoelectric actuator according to the present invention. This fine movement stage 1 has a size of 30mm x 50wn and is fitted into a frame 2, and is supported by a ball bearing 3 with a diameter of 2mo.

It is designed to move left and right like a sliding door.

At the center of both sides of the stage 1 is a 0.5 m convex portion 9 for receiving a spring, which is pushed by flat springs 4 and 5 from the open side. Thickness 0, 4 rtta, width 3 m.

Among the flat springs 4 and 5 having a length of 551I111, spring 5
One end is embedded and fixed in the frame 2, and the other end is compressed by a headless screw screwed into the frame 2.

Since the frame 2 also has a 0.5 m convex part opposite to the convex part of the stage 1, the flat springs 4 and 5 inserted into the 2 m gap between the frame 2 and the stage 1 have a gap of Inm between the convex parts. The range of movement is 0.6m. Flat springs 4, 5
is pressed by the convex portion of the frame 2 and is always warped, so when the screw 8 is tightened, the flat spring 5 is buckled and the stage 1 is moved to the right.

There is also a flat spring 4 on the right side of the stage 1, and a headless screw 7 for adjusting the compression force is set at one end of the spring 2.

The other end has a size of 2 ywr x 3 m x 9 mm and is supported by 50 layers of piezoelectric actuators 6.

When a voltage is applied to the actuator 6, the flat spring 4 buckles and deforms in accordance with the magnitude of the applied voltage, pushing the stage 1 back to the left. When the applied voltage is held at a constant value, the stage 1 is also held at that position.

The relationship between the applied voltage and the displacement of the piezoelectric actuator 6 is shown by a saturation curve, but since the balance of the spring is used, linearity can be maintained more.

Embodiment 2 FIG. 2 shows the fine movement stage described in Embodiment 1 before the linearity of voltage/displacement characteristics was improved, and is basically the same as FIG. 1. The difference is that there are two piezoelectric actuators6,
6 was used in pairs. The linearity has been improved by making stage 1 differential, and the applied voltage is 1
By keeping the voltage constant at 00 volts and applying χ volts and 100-χ volts to the left and right actuators 6 and 6, respectively, the stage 1 is moved by ±50 μm with a resolution of 0.1 μm.
I was able to move slightly.

〔Effect of the invention〕

As explained above, in a stage driven by a piezoelectric actuator, the piezoelectric actuator and a buckling spring are combined as means for moving the stage, and the displacement created by the actuator is magnified by the buckling spring. Therefore, the fine movement stage using the piezoelectric actuator of the present invention.

The structure of the drive mechanism is simple and robust, and the piezoelectric actuator has the advantages of being compact, but the displacement is increased several times to several tens of times, and the displacement with respect to the applied voltage shows saturation characteristics. Since we were able to largely overcome the fatal defects of piezoelectric actuators such as hysteresis, it can be said that the practical needs were satisfied in almost all respects.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a fine movement stage according to Embodiment 1 of the present invention. 1... Stage, 2... Frame, 4, 5...
...Flat spring. 6...Piezoelectric actuator. Figure 1 Figure 3 Figure 2

Claims (1)

[Claims] A fine movement stage driven by a piezoelectric actuator, in which the piezoelectric actuator and a buckling spring are combined as means for moving the stage, and the displacement created by the actuator is magnified by the buckling spring. stage.