JP2002333923A - Device for inspecting precision of motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a motor inspecting device by which length measuring precision is improved by canceling temperature change by using a lightweight and highly rigid base member. SOLUTION: A motor equipped with a horizontally fixed platen and a slider sliding in X and Y directions in a prescribed area on the upper face whose position is controlled is provided as a target of inspection. Then, the thermal expansion coefficient and distance of each member is selected so that a position relation between the central position of an object to be measured (the center of gravity position of the slider) and the mirror face of a target score can be prevented from being changed even when the surrounding temperature is changed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for inspecting position control accuracy of a motor having a horizontally fixed platen and a slider whose position is controlled by sliding a predetermined area on an upper surface thereof in an X direction and a Y direction. About.

[0002]

2. Description of the Related Art A motor to which the present invention is applied is used in a semiconductor manufacturing apparatus such as a prober, and its position control technique is described in a prior application (Japanese Patent Application No.
238149, JP 2000-065970 "XY stage").

[0003] The outline will be described with reference to FIG. (A) is a plan view and (B) is a side view. Reference numeral 1 denotes a platen which is fixed horizontally and has lattice-like teeth formed at a constant pitch along the X-axis direction and the Y-axis direction on the upper surface thereof.

Reference numeral 2 denotes a slider on which an object whose position is to be controlled is placed by sliding a predetermined area on the upper surface of the platen in the X and Y directions. Although not shown, an air ejecting means is provided for floating the slider 2 on the upper surface of the platen 1 by a small distance.

The slider 2 has teeth formed at a constant pitch along the X-axis direction. An X-axis motor for moving the slider in the X-axis direction by generating a magnetic attractive force between the teeth and the teeth on the upper surface of the platen. An X-axis sensor mounted on the X-axis motor for detecting the position of the slider in the X-axis direction, and an X-axis control unit for feedback-controlling the position of the slider in the X-axis direction based on the detection position of the X-axis sensor. Built-in. The Y-axis also includes a Y-axis motor, a Y-axis sensor, and a Y-axis controller.

An X-axis sensor and a Y-axis sensor mounted on the X-axis motor and the Y-axis motor in the slider 2 are realized by an optical distance measuring device, and are formed in the X and Y directions on the outer periphery of the platen 1. Of the slider 2 itself due to the reflection of the laser beams 3a and 3b applied to the mirror surfaces 1a and 1b.
The direction and the Y direction position are measured.

[0007] In order to guarantee the position control accuracy (for example, 1 µm or less) of the motor, an accuracy inspection is performed before shipment or during regular maintenance. 4 is a slider 2 for inspection.
Is a plate-like base member which is detachably fixed in parallel with the upper surface of the platen 1 on the upper surface of the platen 1.

Reference numeral 5 denotes an L-shaped square mirror member mounted on the upper surface of the base member 4 via a suitable attachment, and has leg portions 5a and 5 extending in the X and Y directions.
On the outer surface of b, a mirror surface for reflecting the laser beams 7a and 7b from the externally fixed distance measuring devices 6a and 6b is formed.

Since the position of the square mirror member 5 needs to balance the dynamic characteristics, its center of gravity 8 is
, That is, the center of gravity of the square mirror member is located substantially at the center of the slider 2, so that the distance L1 is necessarily generated between the position of the center of gravity of the slider 2 and the mirror surface of the square mirror member.

In this state, the slider is moved in the entire measuring span in the X and Y directions, and the beams 7a and 7b from the externally fixed distance measuring devices 6a and 6b are reflected by the mirror portion of the square mirror member to move. The distance is measured and it is checked whether the position control accuracy guaranteed over the entire measurement span is maintained.

In FIG. 2B, reference numeral 9 denotes a fixture for the square mirror member 5 fixed to the upper surface of the base member.
The square case 10 has an integral configuration. Reference numeral 11 denotes a conical projection planted on the fixture,
And fixed at a fixed position by engaging with a hole 5c formed at the tip of the leg.

[0012]

In such a configuration of the inspection apparatus, the position of the reflection surface of the square mirror moves with respect to the center value of the measurement object (the position of the center of gravity 8) due to a change in the ambient temperature. The problem of the decrease occurs. That is, when the ambient temperature changes while the slider 2 is stopped, ε: the amount of change due to the temperature expansion of the base member 4. L1: Distance between the center of gravity 8 of the slider and the mirror surface.
α1: coefficient of thermal expansion of the base member. ΔT: temperature change.
Then, since the distance between the center of gravity of the slider and the mirror surface changes by ε = α1 × L1 × ΔT, a measurement is apparently made as if the slider position had changed.

If all parts are made of a material having a coefficient of thermal expansion of 0,
Such a problem does not occur, but the material cost becomes very high. In addition, if all parts are made of a material having a coefficient of thermal expansion of 0, sufficient mechanical strength may not be obtained or the weight may become very heavy.

An object of the present invention is to provide an inspection apparatus which uses a lightweight and high-rigidity base member to cancel the temperature change and improve the length measurement accuracy.

[0015]

In order to achieve the above object, a feature of the first aspect of the present invention is that a horizontally fixed platen and a predetermined area on an upper surface thereof are arranged in an X direction and a Y direction. A motor having a slider whose position is controlled by sliding in a direction is a test object, and a plate-shaped base member fixed detachably to an upper surface of the slider in parallel with an upper surface of the platen, and an upper surface of the base member. Mounted,
A mirror surface for reflecting a laser beam from an externally fixed distance measuring device is formed on the outer surface of the leg portion extended in the X direction and the Y direction, and the center of gravity is arranged at a position corresponding to the center of gravity of the slider. In a motor accuracy inspection device comprising an L-shaped square mirror member and a predetermined length L
A stopper member having one end fixed to the base member and the other end orthogonally contacting the mirror surface of the square mirror member; and a mirror surface of the square mirror member at the other end of the stopper member. And pressing means provided between the base member and the square mirror member so that the mirror member comes into contact with the mirror member. When the distance from the center of gravity to the mirror surface of the square mirror member is L1, α1 × L1 = α2 × L2 Here, α1 is the coefficient of thermal expansion of the base member, and α2 is the coefficient of thermal expansion and the distance are selected so as to satisfy the coefficient of thermal expansion of the stopper member.

A feature of the present invention is that a combination of the stopper member and the pressing means is such that at least one pair is formed on each of the legs of the square mirror member extending in the X and Y directions. It is in.

According to a third aspect of the present invention, the slider has an optical distance measuring device mounted thereon and reflects a laser beam applied to mirror surfaces formed in the X and Y directions on the outer periphery of the platen. Is to measure its own X and Y position.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing an embodiment of a motor accuracy inspection apparatus to which the present invention is applied. The same elements as those described in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

Reference numeral 12 denotes a support plate for the square mirror member 5 fixed to the upper surface of the base member 4, and the support plate 12 in the X and Y directions on this surface.
The direction plane square mirror member 5 is slidable. Reference numerals 13 and 14 denote inverted L-shaped stay members formed on the upper surface of the base member 4, which are provided in the Y-direction legs 5 b and the X-direction legs 5 a of the square mirror member 5 at positions opposite to the mirror surface, respectively. ing.

Reference numeral 15 denotes a stopper member having a predetermined length L2. One end far from the mirror surface is fixed to the upper surface of the base member 4 on the mirror surface side of the Y-direction leg 5b of the square mirror member, facing the stay member 13. The other end close to the mirror surface is arranged so as to contact the mirror surface of the Y-direction leg 5b of the square mirror member.

Reference numeral 16 denotes a spring constituting a pressing means.
Opposite side of mirror surface of square mirror member and stay member 13
Are inserted between the inner wall surfaces. The stay member 13 supports the reaction force of the spring and slides over the frictional force of the square mirror member due to its own weight. Due to this spring force, the square mirror member is constantly pressed in the direction of the arrow P against the free expansion / contraction end side of the stopper member 15.

On the other hand, the free expansion / contraction end of the stopper member 15 in contact with the mirror surface overcomes the reaction force of the spring 16 due to the thermal expansion due to the temperature change, and pushes the square mirror member in the arrow Q direction opposite to the arrow P direction. Act on.

Reference numeral 17 denotes a spring which constitutes auxiliary pressing means inserted between the inner wall of the L-shaped eave portion of the stay member 13 and the upper part of the square mirror member. This prevents the member from lifting when sliding. The configuration of the stay member 14 facing the X-direction leg 5a of the square mirror member is also the same as the configuration of the stay member 13 side.

The relationship between L1 and L2 is dimensioned such that L2 = (α1 / α2) × L1. Here, α1: coefficient of thermal expansion of the base member (6.2 ppm in the example.
MMC PSI-70) α2: expansion rate of stopper (24 ppm in the example. A
5052. L1: Distance from the center of gravity of the slider to the mirror surface L2: Distance from the fixing point of the stopper base member to the mirror surface ε1: Change due to thermal expansion of L1 ε2: Change due to thermal expansion of L2 ΔT: Change in ambient temperature When the temperature changes by ΔT, ε1 = L1 × α1 × ΔT... Similarly, ε2 is opposite in direction to ε1, and ε2 = L2 × α2 × ΔT. Substituting (L2 × α2) into: ε1 = L1 × α1 × ε2 / (L2 × α2) = (α1 / α2) × L1 × (ε2 / L2)

From the above, ε1 = L2 × (ε2 / L2)
Since ε1 = ε2 and the directions are opposite, the distance between the center of gravity of the slider and the square mirror surface is
Take a constant value regardless of the ambient temperature.

[0026]

As is apparent from the above description,
According to the present invention, even if the ambient temperature changes, the positional relationship between the center position of the object to be measured (the position of the center of gravity of the slider) and the mirror surface of the target square does not change. The center position change of an object can be measured correctly.

[Brief description of the drawings]

FIG. 1 is a side view showing one embodiment of a motor control accuracy inspection apparatus to which the present invention is applied.

FIG. 2 is a front view and a side view showing an example of a conventional motor control accuracy inspection device.

[Description of Signs] 1 Platen 2 Slider 3 Laser beam 4 Base member 5 Square mirror member 6 Distance measuring device 7 Laser beam 8 Center of gravity position 9 Mounting bracket 10 Position regulating projection 11 Cover 12 Support plate 13 Stay member 14 Stay member 15 Stopper member 16 Spring (pressing means) 17 Spring (auxiliary pressing means)

Claims (3)

[Claims] An inspection object is a motor having a platen fixed horizontally and a slider whose position is controlled by sliding a predetermined region on an upper surface thereof in an X direction and a Y direction, wherein the platen is provided on an upper surface of the slider. A plate-like base member detachably fixed in parallel with the upper surface, and a laser from an externally fixed distance measuring device mounted on the upper surface of the base member and externally fixed to the outer surfaces of the legs extending in the X and Y directions. An L-shaped scoring mirror member having a mirror surface for reflecting a beam and having a center of gravity coinciding with the center of gravity of the slider; A stopper member having one end fixed to the base member and the other end arranged so as to be orthogonal to and in contact with the mirror surface of the square mirror member; and the other end of the stopper member And a pressing means provided between the base member and the square mirror member so that the mirror surface of the square mirror member is in pressure contact with the mirror member. When the distance from the center of gravity to the mirror surface of the square mirror member is L1, Α1 × L1 = α2 × L2, where α1: the coefficient of thermal expansion of the base member and α2: the coefficient of thermal expansion and distance are selected so as to satisfy the coefficient of thermal expansion of the stopper member. 2. The precision of the motor according to claim 1, wherein at least one pair of said stopper member and said pressing means is formed on each of legs extending in the X and Y directions of said square mirror member. Inspection equipment. 3. The slider has an optical distance measuring device mounted thereon, and reflects its laser beam applied to a mirror surface formed in the X and Y directions on the outer periphery of the platen to reflect its own X and Y directions. 3. The motor accuracy inspection apparatus according to claim 1, wherein the direction position is measured.