JPH0798292B2 - Chain mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a change arm drive device, which has been widely used in recent years in a semiconductor wafer manufacturing and inspecting apparatus, for feeding / removing to / from a manufacturing or inspection process. Regarding

[Prior Art] With the widespread use of computers and the like, in the manufacturing and inspection processes of semiconductor wafers, which are used in large quantities in them, how highly accurate and efficient transportation is a very important issue.

Since the change arm is not the semiconductor wafer manufacturing and inspection process itself, it is not so conspicuous as compared with development in other fields. However, since the transfer by the change arm is a transition from one process to another process or an indispensable front / back process of the process, it is also an important issue how accurately and efficiently this process can be performed.

In the manufacturing or inspection process, accurate positioning of the wafer is necessary for automating the process and for ensuring the accuracy and smoothing the process. There is a correlation with how accurately and smoothly the extraction is performed. Conventionally, the change arm uses a separate drive source for vertical movement and rotational movement to connect both movements with a relay, etc., while using a pulse motor, etc. to improve accuracy, and a lock mechanism. Had adopted. However, parts such as pulse motors are very expensive. In any case, a complicated circuit is required to improve the accuracy.

[Object of the Invention] An object of the present invention is to provide a change arm mechanism which can smoothly and accurately drive a change arm and has a simple structure in view of the above-mentioned drawbacks of the conventional device.

[Summary of the Invention] In order to achieve the above object, the present invention provides a change arm device having a mounting surface on which a wafer is mounted, for taking out a wafer and sending it to the next process. A cam follower attached to the shaft that supports the
A first cylindrical cam having a cam surface for rotating and vertically moving the cam follower and designating a movement trajectory of the cam follower; a first biasing means for biasing an upward force to the cam follower; and the cam follower. Second urging means for urging a force in the rotational direction opposite to the above, and the urging direction is reversed at a predetermined position, and the upward movement of the cam follower is restricted when the cam follower is rotationally moved. A second cylindrical cam that gradually releases the urging force of the first urging means when ascending and moves the cam follower against the urging force of the first urging means when the cam follower descends; the first cylindrical cam and the first cylindrical cam. 2 moving means for relatively moving the cylindrical cam.

[Configuration of the Invention] The present invention will be described below with reference to the drawings of an embodiment of the present invention.

FIG. 1 is a schematic view of a cross section of a change arm portion in a semiconductor wafer inspection apparatus according to an embodiment of the present invention.

Reference numeral 1 is a shaft to which a change arm 2 for mounting a semiconductor wafer is attached, and the shaft and the change arm perform the same movement. Cam follower 8 consisting of two bearings on shaft 1
Is attached so as to be in contact with the cams 5 and 6, and the cam follower 8 moves vertically and horizontally according to the movements of the cams 5 and 6 (because it moves around the axis 1, it is also a rotational movement).
I do. However, although there is a problem in terms of whether the cam 6 can be mechanically called a cam, in the present specification, the cam 6 is also referred to as a cam. The cams 5 and 6 have the shapes shown in the developed view of FIG. 2, and the cam 6 is fixed to the immovable portion. The cam 6 may have a shape as shown in FIG. Reference numeral 7 is a linear motion rotary bearing for smoothing the movement of the shaft 1. 9 is
It is a torsion coil spring in which the direction of rotation is reversed in 90 directions, and applies upward force and force in the direction of rotation to the shaft 1. A torsion coil spring and a compression spring may be used together. A gear 3 is driven by a motor 4, and the motor 4 reverses when the cam 5 rotates 180 times to rotate the gear 3 in the reverse direction.

Next, the operation of this embodiment will be described with reference to FIG. FIG. 2 is a developed view for explaining the movements of the cam follower 8 and the cams 5 and 6, and is a development view showing a positional relationship from 0 to 180.

The spring force acting on the cam follower 8 is indicated by an arrow from the center of the cam follower on the drawing.

The two cylindrical cams are accurately aligned so that the cam follower in FIG. 2 corresponds to the position of the starting point of A (the positions of the two cylindrical cams at this time are shown by solid lines). When the motor 4 is driven, the cam 5 rotates in the 90 direction via the gear 3. When the cam 5 starts rotating in the 90 direction, the cam follower is pressed against the vertical surface of the cam 6 by the spring force,
Along the plane, the center of the cam follower rises vertically until it reaches the height of point B. The spring force acting on the cam follower when moving up the vertical plane is adjusted as shown in FIG. When point B is reached, the upper part of the cam follower is cam 6
Rotate 90 times around point B on the surface. Since the cam follower moves along the cam 6, the conducting wire has an arc, so that the connection is smooth. After that, the cam follower moves to the point C along the horizontal plane of the cam 6 while contacting the cam 5 at the upper part and the cam 6 at the lower part.

At point C, the force in the rotational direction of the torsion coil spring 9 is reversed.
However, since the force of the cam 5 is stronger than the force of the torsion coil spring, the center of the cam follower moves to the point D as it is. After that, it is pushed by the surface of the cam 5 and rotates 90 times around the point D, and while being pushed by the vertical surface of the rear cam 5 by the reversed spring force, it descends to the point E along the surface.

When the motor 3 reverses, the cam follower 8 and the cam return along the path described above.

Since the cam follower 8 is attached to the shaft, the shaft and the change arm move in the direction perpendicular to the rotation direction in accordance with the movement of the cam follower. Therefore, the up / down movement and the rotation movement can be continuously performed by the forward / reverse rotation of the motor 4.

[Effects of the Invention] As is apparent from the above description, according to the present invention, vertical movement and rotational movement can be smoothly and continuously performed by one drive source, and more complicated electrical control is performed. Therefore, it is possible to improve the accuracy of the stop position of the arm.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a cross section of a change arm portion in a semiconductor wafer inspection apparatus which is an embodiment of the present invention, and FIG. 2 shows movements of a cam follower 8 and cams 5, 6. FIG. 3 is a development view for explaining, FIG. 3 is a view showing a spring force acting on a cam follower when ascending on a vertical surface, and FIG. 1 ... axis, 2 ... change arm 5,6 ... cam, 8 ... cam follower 9 ... torsion spring

Claims (1)

[Claims] 1. A change arm device for holding a wafer on which a wafer is placed and for taking out the wafer and feeding it to the next step, and a cam follower attached to a shaft for supporting the placing surface. A first cylindrical cam having a cam surface for rotating and vertically moving the cam follower and designating a movement locus of the cam follower; a first biasing means for biasing an upward force to the cam follower; and a cam follower for the cam follower. Second urging means for urging a force in the rotational direction, which reverses the urging direction at a predetermined position, and the upward movement of the cam follower when the rotational movement of the cam follower is restricted. And a second cylindrical cam which gradually releases the biasing force of the first biasing means and moves the cam follower against the biasing force of the first biasing means when the cam follower descends.
A change arm device comprising: a moving unit that relatively moves the first cylindrical cam and the second cylindrical cam.