JP2607272B2 - XY table and probe device using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to an XY table.

(Prior Art) An XY table used to drive an object in X and Y directions has been adopted in various fields, but as a configuration for movably supporting an XY stage on a solid stage base. The following configuration is adopted.

That is, there is a type in which the lower surface of the XY stage itself is polished and used as a planar bearing, or a type in which a planar bearing having a large area is arranged on the lower surface of the XY stage and used as a planar guide. there were.

In some cases, a flat bearing is mounted and fixed to the lower surface of the XY stage at a plurality of locations.

(Problems to be Solved by the Invention) In the case where the lower surface of the XY stage itself is a plane bearing and the case where a plane bearing having a large area is used as a plane guide, the processing surface accuracy of the plane bearing is wide. Relatively high precision is required over the area, and the processing cost has made the apparatus expensive. When the XY stage has a warp or the like, since the XY stage is supported in a planar manner over a wide area, the warp cannot be absorbed, and the XY stage 7 may have stress remaining on the flat bearing or may not be supported. However, there were problems such as instability.

On the other hand, even when mounting planar bearings at a plurality of locations, it is necessary to accurately surface the mounting positions of the planar bearings of the XY stage, and furthermore, a flat surface whose thickness etc. is managed with considerably high precision. The bearing had to be fixed. For this reason, it is necessary to simultaneously process a plurality of flat bearings so as to obtain the same height, and it is necessary to perform considerable fine adjustment when assembling the XY stage.
Assembly was complicated.

Therefore, an object of the present invention is to solve the above-mentioned conventional problems and to provide an inexpensive X that can be easily assembled without requiring excessive machining accuracy and without adjustment or the like. -To provide a Y table and a probe device using the same.

[Structure of the Invention] (Means for Solving the Problems) The present invention relates to an XY table for driving an XY stage two-dimensionally on a stage base. Between them, planar bearings are arranged at three positions that are not on a straight line, and a sphere is interposed between the planar bearing and the XY stage.

As the flat bearing, a hydrostatic air bearing, a sintered oil-impregnated bearing, a flat bearing using ordinary oil lubrication, or the like can be used. This XY table can be suitably implemented as an XY table for moving a test object of a probe device for inspecting electrical characteristics by moving the test object in a two-dimensional manner.

In order to prevent the XY stage from being separated from the sphere, the plane bearing and the XY stage have a degree of freedom in the rotation direction so that at least the inclination of the XY stage is allowed. It is preferable to connect them.

(Operation) The XY stage is movably supported on a two-dimensional XY plane by plane bearings arranged at three positions that are not linear with the stage base. Where X
Since the -Y stage has a sphere interposed between it and the plane bearing, the accuracy of the height in the Z direction of the plane bearing supporting the sphere is not excessively required. Even if they are different, the XY stage can be rotated so as to be tilted through the sphere, so that the gap between the three plane bearings and the stage base can be properly maintained, and no gap change occurs between them. Therefore, the bearing function can always be properly exerted.

The support of the XY stage by this sphere is
Although it depends on the groove shape on the Y stage side, any of point contact, line contact and spherical contact can be supported with a degree of freedom in the rotation direction of the XY stage. Even if the flatness of the stage is poor, the XY stage can be stably supported without backlash by rotatable contact support at three places.

Furthermore, since the area of the portion where the XY stage contacts the sphere is small, the XY stage contact surface is not required to be very accurate, and the XY stage is supported by three points of contact. it can.

(Examples) Hereinafter, the present invention will be specifically described with reference to the illustrated examples.

As shown in FIG. 1, an XY stage 2 having three planar bearings 3 is provided on a stage base 1.

The plane bearings 3 are installed at three points on the back surface of the XY stage 2 that are not aligned to determine the guided surface of the XY stage 2. In the case of this embodiment, XY
The stage 2 is installed such that a line connecting the centers of the three planar bearings 3 on the back surface of the stage 2 becomes a substantially equilateral triangle. Also, X
-It is desirable to determine the installation position of the flat bearing 3 so that the center of gravity of the Y stage 2 is inside the equilateral triangle.

Next, an example of the connection between the XY stage 2 and the flat bearing 3 will be described with reference to FIG.
The flat bearing 3 has a conical groove 2
a, 3a are formed, and a sphere ball 4 is interposed between the grooves 2a, 3a.

Further, the XY stage 2 may be simply supported on the plane bearing 3 via the ball 4, but in this embodiment, the hollow cylindrical cover 5 having an inner diameter slightly larger than the outer diameter of the plane bearing 3 is provided. And the upper flange 5a is connected to the X-
A hole 5b through which two or more shafts 6 projecting from the periphery of the flat bearing 3 and screwed to the Y stage 2 are inserted.
Are formed on the peripheral surface of the cover 5 corresponding to the number of the shafts 6. The hole 5b may be formed much larger than the shaft 6.

 Next, the operation will be described.

The XY stage 2 is supported on the stage base 1 by a flat bearing 3, and since the frictional resistance between the flat bearing 3 and the stage base 1 is small, the XY stage 2 is mounted on the X, Y When driven in the direction, the plane bearing 3 slides on the stage base 1, so that the XY stage 2 that moves integrally with the plane bearing 3 can be driven in the X and Y directions.

Here, in this embodiment, the flat bearing 3 is not directly attached to the XY stage 2, but the ball 4 is interposed between them.

Therefore, the groove 2a of the XY stage 2 and the ball 4
Does not contact in a plane and follows the spherical surface of ball 4 and
The Y stage 2 is supported with a degree of freedom in the rotation direction so that it can be tilted in any direction.

As described above, since the XY stage 2 is supported by the ball 4 while being allowed to rotate, the XY stage 2 operates as follows.

In other words, according to the conventional planar bearing that supports a plurality of locations, the XY stage is supported in a planar manner, so that the heights of the planar bearings that are arranged at the plurality of locations need to be strictly controlled. For example, high-precision machining is required by simultaneously machining a plurality of planar bearings. If this is not done, the heights of the planar bearings arranged at a plurality of locations will vary, which will result in unstable support of the XY stage.

However, in the case of the present embodiment, even if the height of the flat bearings 3 varies, the XY stage 2 rotates via the ball 4 and tilts according to the difference in the height. XY stage 2 can be reliably supported even if such a slight inclination occurs, and stable support can be always ensured. For such support, the flat bearing 3, X-
No extra load acts on the Y stage 2.

Further, when the XY stage 2 is driven and accelerated, a change in the gap occurs instantaneously between the plane bearing 3 and the stage base 1, resulting in a change in the attitude of the XY stage 2. In such a case, X-
The fluctuation component can be absorbed by rotating the Y stage 2.

Further, when the conical groove 2a and the ball 4 are supported in contact with each other as in the above-described embodiment, XY can be obtained by line contact.
Although the stage 2 is supported, since the contact area with the ball 4 is small, the XY stage 2 is not required to transiently require the surface projection accuracy of the contact portion. However, the processing accuracy is much lower.

In this embodiment, the flange 5a of the cover 5 is fixed to the XY stage 2 and the shaft 6 of the flat bearing 3 is inserted through a hole 5b formed in the cover 5 so that the XY stage 2
The shaft 6 and the hole
The XY stage 2 and the flat bearing 3 can be integrated without being separated by engagement with the 5b. Then, in this case, in order to maintain the freedom of rotation of the XY stage 2,
If the hole 5b has a diameter considerably larger than that of the shaft 6, the XY stage 2 can be rotated within a range allowed by the hole 5b.

Note that the cover 5 and the like as described above are not necessarily required,
Even without this, there is no problem in driving the XY stage 2. That is, the groove 2a of the XY stage 2, the ball 4,
The frictional resistance of the groove 3a of the planar bearing 3 is much larger than the frictional resistance between the lower surface of the planar bearing 3 and the stage base 1,
Therefore, when the XY stage 2 is driven, a sliding movement occurs between the plane bearing 3 and the stage base 1, and the ball 4 does not come off the grooves 2a, 3a. Can move on the stage base 1 integrally.

Here, as the above-mentioned flat bearing, in addition to a hydrostatic air bearing and a sintered oil-impregnated bearing, a flat bearing using ordinary oil lubrication can be used. Considering this, it is preferable to use a static pressure air bearing. When a static pressure air bearing is employed, a nipple of an air supply tube can be used instead of the shaft 6.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention.

For example, various modifications can be made to the supporting form of the ball 4, and the shape of the groove or the like having a conical shape is excellent in that the contact is small and the ball 4 can be securely prevented from coming off. The XY stage 2 may be rotatably supported following the spherical surface of the ball 4.

FIG. 3 shows another supporting form of the XY stage 2, in which a cover 10 fixed to the XY stage 2 by screws or the like is formed in a bottomed cylindrical shape, and is provided on the inner bottom surface. A conical groove 10a is formed, and a hole 10b through which the shaft 6 is inserted is formed in the cylindrical side surface. Even in this case, the same effect as in the case of FIG. 2 can be obtained.
The -Y stage 2 is excellent in that it can be assembled without any processing.

Note that the XY table according to the present invention uses the
The present invention can be applied to various devices that move arbitrarily on the Y plane, and can be suitably used for a wafer stepper, an aligner, a wafer prober, a laser prober, a memory repair device, and the like.

[Effects of the Invention] As described above, according to the present invention, the XY stage is supported even if the shape processing accuracy of the XY stage is poor or the accuracy in the height direction of the flat bearing varies. By supporting the XY stage rotatably following the sphere, the XY stage can be properly supported without requiring high-precision processing of other parts, and adjustment during assembly Because it is not necessary, X is easy and cheap to assemble.
-A Y table can be provided.

[Brief description of the drawings]

FIG. 1 is a plan view of an XY table of the present invention, FIG. 2 is a schematic cross-sectional view for explaining connection between a plane bearing and an XY stage, and FIG. It is a schematic explanatory view for explaining the modification of connection with a Y stage. 1 ... Stage base, 2 ... XY stage, 2a ... groove, 3 ... Plane bearing, 3a ... groove, 4 ... sphere (ball), 5 ... cover, 5a ... flange, 5b ... ... holes, 6 ... shafts, 10 ... covers, 10a ... grooves, 10b ... holes.

Claims (3)

(57) [Claims] 1. An XY table for two-dimensionally driving an XY stage on a stage base, wherein planar bearings are provided at three non-linear positions between the stage base and the XY stage. And an XY table, wherein a sphere is interposed between the flat bearing and the XY stage. 2. The device according to claim 1, wherein the center of each of the three planar bearings is located substantially at the vertex of the equilateral triangle, and the center of gravity of the XY stage is located inside the equilateral triangle. An XY table, wherein the planar bearing is arranged. 3. An XY table according to claim 1 or 2, wherein an object to be inspected is moved on an XY plane by the XY table, and electrical characteristics of the object to be inspected are determined. A probe device for inspecting.