JPH0981244A - Work transfer device - Google Patents

Abstract

(57) [PROBLEMS] To provide a work transfer device capable of precisely transferring a work to a predetermined position and preventing damage to the work at that time. An arm 4 provided on a Z stage 10, a θ stage 11, and a Y stage 12 rotates around a rotation shaft 5. A reference fixed to the X stage 13 while the position of the work 2 gripped by the work grip 3 by the X stage 13, the θ stage 11, and the Y stage 12 is vacuumed by the image information obtained from the imaging device 26. It moves directly below the surface 1 and comes into contact with the reference surface 1 by the Z stage 10. When the proximity sensor 9 detects the contact, the Z stage 10 is stopped. Furthermore, work 2
Is held on the reference surface 1 by vacuum, and the work holding part 3
The grip is released.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work transfer device for gripping a work and precisely transferring it to a predetermined position.

[0002]

2. Description of the Related Art Conventionally, as a method of gripping a work and precisely transferring it to a predetermined position on a reference surface, a moving means (for example, a vertical movement stage) provided with a linear guide by a combination of a linear shaft and a linear bushing is used. ), The method of directly transferring the work to the reference surface is general. In this case, the position of the work is detected by image processing or the like before the contact, the position of the work is corrected based on the position information, and the contact of the work with the reference surface is detected, so that the work is determined to be predetermined. Determine if it is in position. As a method of detecting the contact, detection by image processing using an imaging device Detection of load fluctuations on the work feed drive system, or detection of load fluctuations at the time of workpiece contact using a pressure sensor, etc. Contact or non-contact type There is a method of detecting the distance between the work and the reference surface using the above sensor.

[0003]

However, in the above-mentioned conventional example, as a problem for precisely transferring the work to a predetermined position on the reference surface, in the case of the above, the work is provided near the upper or lower part of the work. An image pickup device or the like for performing image processing must be installed as the position detection device. That is, there is a reference surface with which the work comes into contact at one end in the vertical direction with respect to the work, and the image pickup device is installed at the other end. In this configuration, for example, the vertical movement stage that moves the work cannot be physically installed directly below or directly above the work, and thus must be installed at a position away from the work. For this reason, an arm for gripping the work is used, one end of the arm is fixed to the work grip, and the other end is fixed to the vertical movement stage. Therefore, there is a problem in that the space occupied by the device increases, the cost increases due to the complexity of the device, and the takt time increases due to the increase in the number of processes.

In the case of the above case, it is necessary to detect a minute value of load fluctuation and distance change, but due to factors such as sensor hysteresis, a value below a certain value cannot be detected. That is, the "contact" cannot be detected until the upper and lower stages have been moved to some extent from the moment when the work contacts the reference surface. Also, when the workpiece comes into contact with the reference surface, if the movement of the vertical movement stage is not stopped at the moment when the workpiece comes into contact, the moment load due to the above-mentioned configuration in which the workpiece gripping part and the vertical movement stage are separated causes Problems such as stage tilt, work position displacement, and damage will be a problem. Further, if the operating speed is lowered to stop the movement of the vertical movement stage at the position of the contact, the increase of the tact time becomes a problem.

Therefore, the present invention has been made for the above, and an object thereof is to provide a work transfer device capable of precisely transferring a work to a predetermined position and preventing damage to the work at that time. To do.

[0006]

As a constitution of the present invention for achieving the above-mentioned object, claim 1 holds a work having two parallel surfaces, and the work is provided on a target flat reference surface. Abutting one surface in parallel with the reference surface,
In a workpiece transfer device for transferring, arm means rotatable about a rotation axis parallel to the reference plane, and a first end portion of the arm means, the workpiece being parallel to the reference plane. A work transfer device comprising: a gripping means for gripping, and a moving means for moving the arm means so as to bring the work into contact with the reference surface while the gripping means grips the work. .

As a result, the work which is easily damaged is precisely transferred to the reference surface, and the movement of the arm after contacting the work is minimized.

According to a second aspect of the present invention, there is provided at the second end portion of the arm means a detection means for detecting that the work is in contact with the reference surface. It is a device.

Thus, the increase in the moment of inertia due to the increase in the weight of the first end portion of the arm which requires the positioning while holding the work is suppressed.

According to a third aspect of the present invention, the distance from the center of the rotating shaft to the second end is the distance from the center of the rotating shaft to the first end.
The distance is longer than the distance to the end of the.
It is the work transfer device described.

As a result, the movement amount of the work held by the arm is amplified and detected.

According to a fourth aspect of the present invention, the surface formed by the center of the rotation axis of the arm means and the other surface facing the surface holding the workpiece by the arm means is substantially parallel to the reference surface. The work transfer device according to claim 1 or claim 3.

As a result, the movement of the arm after the contact with the work is minimized.

A fifth aspect of the present invention is the work transfer apparatus according to the first aspect, wherein the work is a semiconductor chip.

As a result, semiconductor chips that are easily damaged and have variations in thickness within the tolerance range can be transferred accurately.

A sixth aspect of the present invention is the work transfer apparatus according to the first aspect, wherein a vacuum is used for the grip means.

This prevents the work from being contaminated and damaged.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

First, the overall construction of a work transfer device according to an embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a top view of a work transfer device as an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of the work transfer device as an embodiment of the present invention.

FIG. 3 is a sectional view taken along line BB of the work transfer device as one embodiment of the present invention.

In the figure, the reference surface 1 is fixed to an X stage 13 installed in parallel with a base 22, and a vacuum air hole 23 for holding the work 2 when the work 2 abuts is provided. There is. Reference numeral 18 denotes an air joint to which a pipe for circulating the vacuum air is attached, and the air pipe is connected to a vacuum source (not shown). When the work 2 comes into contact with the reference surface, the vacuum source acts by switching the solenoid valve or the like,
Hold the work. The X stage 13 is movably installed by a base 19 fixed to a ceiling portion (not shown), and its moving direction is the front-back direction with respect to FIG.

The work gripping portion 3 is attached to one end of the arm 4, and, like the reference surface 1, is provided with vacuum air holes 15 and 16 for gripping the work 2, and the air joint 17 is the same as described above. Connected to a vacuum source (not shown).

A proximity sensor 9 and a stopper bolt 8 are attached to the bracket 25, and are attached to the rear of the housing 6.

The arm 4 and the rotary shaft 5 are fixed by a pin 14 and rotate integrally with the rotary shaft 5 as a center. Furthermore,
At the other end 4a of the arm 4, a highly accurate proximity sensor 9 for detecting a slight rotation of the portion 4a, a stopper bolt 8 for positioning the arm 4 and a tension spring 7 for returning the rotation of the arm 4 are installed. ing. It should be noted that, in FIG. 2, the straight line connecting the opposite gripping surface of the workpiece 2 gripped by the arm 4 and the center of the rotary shaft 5 is also parallel when the arm 4 is parallel to the base 22.

Both ends of the rotary shaft 5 are rotatably supported by bearings 20 incorporated in the housing 6.
In addition, the bearing retainer 24, which prevents the arm 4 from wobbling in the direction perpendicular to the rotary shaft 5, has two bearings 2.
The outer ring of 0 is preloaded in the axial direction to increase its rigidity.

At the lower part of the housing 6, a stage (hereinafter referred to as X) that can move the work 2 up to the reference plane 1 is movable.
There is stage 10. Also, fixed to the base 22,
A rotary stage (hereinafter referred to as a θ stage) 11 capable of detecting the position of the work 2 by an image pickup device 13 for image processing for picking up the position of the work 2 from below and correcting the position in the rotation direction, FIG.
A stage that can correct the horizontal position in
Y stage) 12 is provided. Also, the imaging device 1
3 is a control device 3 of the transfer device via the image processing device 40.
Connected to 0.

FIG. 4 is a block diagram of the control device of the transfer device as an embodiment of the present invention.

In the figure, 30 is a control device of the transfer device,
Reference numeral 31 is a keyboard for inputting an operation program and parameters of the transfer apparatus, 32 is a CPU for calculating the operation of the transfer apparatus based on the operation program and position information of the work 2 after image processing, and 33 is an operation program and fixed parameters. Is stored in ROM, 34 is RAM used for temporary storage of variable parameters and as a working area, and 35 is CR.
A display device such as T, an input / output end interface 36 for inputting the proximity sensor 9 and outputting an electromagnetic valve (not shown),
Reference numeral 37 is a servo system interface for controlling each stage in accordance with a command from the CPU 32, and 38 is the image processing apparatus 4.
It is a communication interface for image data that communicates with 0. A bus 39 for communicatively connecting these inside the control device 30 is provided.

Next, the operation of the transfer apparatus will be described with reference to FIGS. 5 and 6. Work 2 as a premise of operation
Are mounted on the work gripping part 3 of the transfer device by a device (not shown). Therefore, the work 2 is precisely transferred to the reference surface 1 by the transfer device, and then moved to a place (not shown) for performing the next step by the X stage 13. Further, the control of the solenoid valve (not shown) that grips the work 2 uses a software timer on a program, and does not use a vacuum switch or the like.

FIG. 5 is a flow chart showing a transfer process as an embodiment of the present invention.

In the figure, in step S1, the image pickup device 2
The operations of the θ stage 11, the Y stage 12, and the X stage 13 are controlled on the basis of the image data of the work 2 imaged in 6, and the work 2 is corrected so as to be located immediately below a predetermined position on the reference surface 1. Next, step S2 to step S4
, The proximity sensor 9 turns off the Z stage 10 (ON
Then, the arm 4 is lifted until it becomes 4a.
Next, in step S5, the vacuum on the reference surface 1 side is actuated, the elapse of the set time of the timer T1 in step S6, the vacuum pulling on the work holding part 3 side is stopped in step S7, and the timer T2 in step S8 After the set time has elapsed, the Z stage 10 is lowered to the initial position in step S9. This allows work 2
The transfer from the workpiece gripping portion 3 to the reference surface 1 is completed.

Here, a supplementary explanation of the operation of the arm portion of the transfer device will be made. At the end of step S2 in FIG. 5, the work 2 contacts the reference surface 1, but the Z stage 10 slightly moves up. . In the meantime, the arm 4 is centered on the rotary shaft 5, the workpiece gripping portion 3 side is in the −Z direction, and the other end is + Z.
Lean in the direction. Due to this inclination, the distance between the portion 4a of the arm 4 and the sensor 9 increases, and the proximity sensor 9 is turned off. This stops the Z stage 10 from rising. That is, after the work 2 comes into contact with the reference surface 1, the Z stage 1
The movement of the Z stage 10 until 0 stops adversely affects the positioning of the work 2. To solve this problem, according to the configuration of the present invention, the distance L2 from the center of the rotary shaft 5 to the proximity sensor 9 may be made longer than the distance L1 from the center of the rotary shaft 5 of the arm 4 to the workpiece 2. Next, work 2
How to determine the position of the arm central axis 5 will be described with reference to FIG.

FIG. 6 is a diagram showing the positional relationship between the work 2 and the arm central axis 5 as an embodiment of the present invention.

In the figure, the rotation center of the arm 4 is A in the + Z direction.
→ When moving to A ', at each point on the same radius L1 from the point A, the further away from the point A, the more a → a', d →
The change amount after d'is large. In the case of the present invention, b →
Corresponds to b '. The point c on the drawing is ideal because the position before and after movement is the same, but in practice, the amount of movement from A to A'is a variation within the thickness tolerance of the workpiece 2, and an error during measurement. However, the C point is different every time even if the C point is obtained because of variations in the position of the reference plane 1 and the like. Further, when the thickness dimension of the work 2 is small, c≈b. Therefore, for practical reasons, the work contact surface is described at the point b. In order to eliminate the distance (b → b ′) (that is, to keep the contact state between the work 2 and the reference surface 1 parallel to each other), the Y stage 12 is moved to the position in step S1 of FIG. It is ideal to move again after correction, but the work 2 has a thickness of 1 mm.
The following semiconductor chips are easily damaged and have variations in thickness within the tolerance range. Therefore, since it is not realistic to perform the correction process by rotating the arm 4 for each work, the method shown in FIG. 6 is adopted.

<Modification of Embodiment> 1. Fixing force F1 between the work and the work grip on the arm side
When the force F2 that moves in a direction that shifts the position of the work when the work is slightly tilted after contacting the reference surface is F1 <F2, the rotation center of the arm and the work are The contact surfaces may be the same plane. However, F1 <F2
In the case of, in order to prevent the work from being misaligned between the work gripping portion and the work, and thereby preventing the work from being scratched, the rotation center of the arm and the work gripping surface of the arm should be flush with each other. . 2. When the thickness of the work is large, it may be more effective to set the plane coinciding with the rotation center of the arm near the center of the thickness of the work. 3. In the above-described embodiment, the work is transferred from the bottom to the top, but the work may be transferred from the top to the bottom. 4. A mechanical clamp or the like may be used to fix the work.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of one device. Further, it goes without saying that the present invention can be applied to the case where it is implemented by supplying a program to a system or an apparatus. In this case, the storage medium storing the program according to the present invention constitutes the present invention. Then, by reading the program from the storage medium to the system or device, the system or device operates in a predetermined manner.

<Effects of the Embodiment> (1) From the rotation center axis 5 to the proximity sensor 9 (4a portion of the arm 4) rather than the distance L1 from the rotation center axis 5 of the arm 4 to the work 2 (work holding portion 3). By increasing the distance L2 of, the proximity sensor 9 can detect the movement of the workpiece 2 in the Z direction by amplifying it by L2 / L1 times. As a result, the amount of movement of the Z stage 10 after contacting the work 2 can be minimized, and the work 2 can be accurately positioned. (2) By setting the positional relationship between the center of the rotating shaft 5 of the arm 4 and the contact surface of the work 2 to be on the same plane (the same height surface with respect to the reference surface 1), the Z stage 10 after contact with the work The positional deviation of the work 2 due to the movement is minimized to prevent the work 2 from being damaged. (3) Since the work gripping portion 3 is provided at one end of the arm 4 and the proximity sensor 9 is provided at the other end, the end of the arm 4 on the work gripping portion 3 side that needs to be positioned while gripping the work. It suppresses the increase of the moment of inertia due to the increase of weight and facilitates the positioning by each stage.

[0040]

As described above, according to the present invention, it is possible to provide a work transfer device capable of precisely transferring a work to a predetermined position and preventing damage to the work at that time.

[0041]

[Brief description of drawings]

FIG. 1 is a top view of a work transfer device as an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of the work transfer device according to the embodiment of the present invention.

FIG. 3 is a BB cross-sectional view of the work transfer device as the embodiment of the present invention.

FIG. 4 is a block configuration diagram of a control device of the transfer device as an embodiment of the present invention.

FIG. 5 is a flowchart showing a transfer process as an embodiment of the present invention.

FIG. 6 is a diagram showing a positional relationship between a work 2 and an arm central axis 5 as one embodiment of the present invention.

[Explanation of symbols]

 1 Reference plane 2 Work 3 Work gripping part 4 Arm 5 Rotating shaft 6 Housing 7 Tension spring 8 Stopper bolt 9 Proximity sensor 10 Z stage 11 θ stage 12 Y stage 13 X stage 14 pin 15 Vacuum hole 16 Vacuum hole 17 Air joint 18 air joint 19 base 20 bearing 21 nut 22 base 23 hole for work vacuum air 24 bearing retainer 25 bracket 26 imaging device 27 lens 30 controller 31 keyboard 32 CPU 33 ROM 34 RAM 35 display device 36 input / output end interface 37 servo system Interface 38 Communication interface for image data 39 Bus 40 Image processing device

Claims (6)

[Claims] 1. A work transfer device for gripping a work having two parallel surfaces and abutting one surface of the work on a target flat reference surface in a state parallel to the reference surface and transferring the work. In which arm means rotatable about a rotation axis parallel to the reference plane, and gripping means located at a first end of the arm means for gripping the workpiece parallel to the reference plane, A work transfer device comprising: a moving unit that moves the arm unit so that the work is brought into contact with the reference surface while the gripping unit holds the work. 2. The work transfer device according to claim 1, further comprising detection means for detecting that the work is in contact with the reference surface at a second end portion of the arm means. 3. The distance from the center of the rotating shaft to the second end portion is longer than the distance from the center of the rotating shaft to the first end portion. Work transfer device. 4. The surface formed by the center of the rotating shaft of the arm means and the other surface facing the surface holding the work by the arm means is substantially parallel to the reference surface. The work transfer device according to claim 1 or claim 3. 5. The work transfer device according to claim 1, wherein the work is a semiconductor chip. 6. The work transfer device according to claim 1, wherein a vacuum is used for the gripping means.