JPH01257347A - Gripping apparatus - Google Patents

Abstract

PURPOSE:To surely execute a gripping operation and to prevent an accident due to a drop during a transfer by a method wherein a heating part is installed at a laminated body at least on one out of a first gripping body and a second gripping body, the heating part is controlled by a signal from a sensor used to detect a gap between claw parts during a gripping action and a curvature amount of the gripping body is controlled. CONSTITUTION:A first gripping body 9 where claw parts 3a, 3b have been installed at its tip parts and a second gripping body 10 where a claw part 3c has been installed at its tip part in the same manner are coupled to a main body 6. At least one out of the first and second gripping bodies 9, 10 is a laminated body of two or more metals; heating parts 14a, 14b are installed at the laminated body. In addition, the following are provided: sensors 13a, 13b used to detect a gap between the claw parts 3a-3c during a gripping action; a control means used to control a curvature amount of the first and second gripping bodies 9, 10 by controlling the heating parts 14a, 14b. On the basis of a signal from the sensors 13a, 13b, the first and second gripping bodies 9, 10 follow a deformation of the claw parts 3a-3c and execute a gripping operation surely. By this setup, an object to be gripped can be gripped without being dropped during a transfer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a gripping device for gripping a substrate such as a semiconductor wafer.

(Prior Art) Taking the field of semiconductor technology as an example, in a so-called wafer process, a semiconductor wafer (hereinafter referred to as a substrate) is transported to various processes and subjected to various treatments. In the above-mentioned conveyance, when a plurality of substrates stored vertically in a rack are taken out one by one and transferred to a belt conveyor, a vacuum suction type gripping device is mainly used. Although this gripping device has the advantage of a simple structure, it is extremely weak against shearing forces perpendicular to the suction direction, which often causes the substrate it is gripping to fall, resulting in poor gripping reliability. There was a problem. In order to solve this problem, the seventh
A gripping bag Wl(1) as shown in the figure has been proposed and is in use. That is, the above-mentioned gripping device has a pair of finger parts (2a) and (2b) divided into a U-shape, and targets claw parts (la) and (lb) consisting of small drum-shaped rollers at their tips. The first grip body (4) provided at the position and the finger portion (2a) -
(2b) and can move forward and backward on the same plane along the direction of these finger parts, and the claw part (3a) is located at the tip of the finger part.
, (3b) and a second gripping body (5) provided with a claw portion (3C) having the same shape as that of (3b), and a movement mechanism (not shown) for the second gripping body (5) that accommodates the first and second gripping bodies. ) and the first gripper (
A main body (6) equipped with a buffer mechanism (not shown) for 4).
The main body (8) is attached to a robot arm, etc., and the advance/retreat mechanism is controlled and driven together with the robot arm, and each claw part (3a), (3B), (3
In c), the outer part of the substrate (7) indicated by the dashed line in the figure is gripped at approximately equal angles to transfer the substrate. Incidentally, the gripping device (1) is also used to transfer substrates (7) that are lined upright on a boat after being subjected to high-temperature treatments such as impurity diffusion and oxide film formation in a processing furnace.

(Certification to be Solved by the Invention) The above-mentioned gripping device (1) has no particular problem in gripping and transferring the substrate (7) when it is at room temperature, but it is difficult to grip the substrate (7) immediately after it has been subjected to high-temperature treatment. The following problems occurred. That is, the substrate is thin, and due to oxide film formation, etc., there is a difference in linear expansion coefficient on both sides, causing it to warp to one side or deform into an irregular shape.
), (3b), and (3c), especially the gap between the central claw part (3C) and the outer part of the board (7),
I couldn't grasp it enough.

For this reason, the substrates were dropped during transfer, which caused a decrease in yield. The present invention was made in view of the above circumstances, and an object of the present invention is to provide a gripping device that can grip an object to be gripped, such as a substrate that has been deformed by heat treatment, without falling during transfer.

[Structure of the invention] (Means and effects for solving the problem) A first gripping body that supports at least two points on the outer side of the thin plate-like member, and a first gripping body that supports the thin plate-like member at least A second gripping body supporting at least three points on the outer side and at least one of the first and second gripping bodies are a laminate of a plurality of metals having different coefficients of thermal expansion, and the laminate is provided with a sensor provided on at least one of the first and second gripping bodies to detect a gap between the heating section and the thin plate member during a gripping operation; The configuration includes a control means for controlling the amount of warpage of the first and second gripping bodies, and the first and second gripping bodies are deformed to follow the deformation of the thin plate member in response to a signal from the sensor. To securely grip a deformed thin plate member.

(Example) EMBODIMENT OF THE INVENTION Hereinafter, the present invention will be described based on drawings showing examples.

Note that parts common to those in FIG. 7 will be described with the same reference numerals. In Fig. 1, (8) is a gripping device, which has U-shaped finger parts (9a) and (9b), and has claw parts (3a) and (3b) at the tips of these fingers. 1 gripper (
9) and a second gripping body (lO) having a claw portion (3C) at the tip thereof are engaged with the main body (6). In the present invention, the first and second gripping bodies are both bent to one side by heating control, but they are structurally based on the same principle, and for convenience of explanation, the second gripping body (10
) will be explained.

That is, in the second gripping body (10), the main body (6)
The length of the part protruding from the outside is approximately 2
The length is 50 mm, and the length 100 mm from the tip where the claw part (3C) is provided is a laminate with a three-layer structure. That is, the width is 10 mm, the thickness is 1 cm, and the material is Pe-Ni (36
%) alloy and is connected to the main body (6) (1
1) is joined to both sides of this member (11), the width and thickness are the same, and the material is N1 (74%)-Cr (20%).
- Member (12a) made of Fe (6%) alloy, (1
2b). Therefore, the claw part (3C)
is provided on one member (12a). On the side of the member (12a) where the claw portion (3C) is provided, an optical sensor 1 (13a) that converts changes in the amount of light received into an electrical signal is provided at a location close to the claw portion (3C). The same optical sensor (
13b) is provided. A standard board with no warpage is gripped between the claws (3a), (3b), and (3c), the member (13a), and the optical sensor 1,
2 The distance between (13a) and (13b) is approximately 1mff
It is 1. Additionally, heater 1 (14a) and heater 2 are connected to this member (12a) and the other member (L2b).
(14b) are buried respectively. Further, thermocouples A are provided at the tips of the members (12a) and (12b), respectively.
(15a) and B (15b) (not shown) are attached. Optical sensors 1, 2 (13a), (13b)
and heaters (14a), (14b) and thermocouple A
, B (15a), and (15b) are connected to the control circuit section (I6) via respective lead wires.

The configuration of this control circuit section (16) is as shown in FIG.
The magnitude of the amplified detection signal from the optical sensor is determined, only the large signal is passed through, and the signal is transmitted to the optical sensor 1 (13
The set value from the set value circuit (18) and the set value from the set value circuit (18) and the set value are output from the set value circuit (18). A comparator (19) compares the set value that is input and the detected detection signal determined above, and (+) and (-
), the A/D converter (20) converts the signal into a signal of
a power supply control unit (21) that energizes either the heaters 1 or 2 based on the signal from the D converter (20);
Input the above signal of /D converter (20), thermocouple A,
It consists of an opening/closing control section (22) that turns on/off the power supply to the heater 1.2 of the power supply control section (21) based on the signals from B (15a) and (15b).

Here, in the set value circuit (18), the second gripping body (lO)
Optical sensors 1, 2 (13a), (
The detected value of 13b) is stored as a set value. Comparator (19) Teha 1st. Second gripping body (4), (10)
(7) The grasping operation start signal (25) is sent to the comparator (19) via a separate route, and the respective set values and detected values are compared.

In this comparison, if there is no difference, the command output from the comparator (19) to the A/D converter (20) will be zero, and if the detected value of optical sensor 1 is greater than the detected value of optical sensor 2. In this case, heater 1 (14a) is energized as a (+) displacement from the A/D converter (20), and in the opposite case, heater 2 (14b) is energized as a (-) displacement from the A/D converter (20). ) The configuration is such that the device is energized.

The opening/closing control section (22) also includes members (11) and (12a).
), the combination of members (11) and (12b) is each made of bimetal, and a function is provided to set the temperature difference Δt from the vertical change d of the free end when supported by a cantilever. For that setting, Δ1-dh/k is added to the above function.
A calculation formula for 1 (where h is the plate thickness, 1 is the length of the bimetallic part, and k is the curvature coefficient) is incorporated.

On the other hand, in the first gripping body (9), the fingers (9a), (9
The common part (9c) that connects the first gripping body (10
) has a laminate similar to the above-mentioned three-layer structure, and is warped in the direction of arrow X in a direction perpendicular to the plane of the paper. That is, the power is output from the power supply control unit (21), a circuit line (30) of a separate system from the second gripping body (10) is provided, and the first
The circuit wire (30) is selected and heated so that the heater 3.4 (both not shown) incorporated in the second gripper (9) warps in the same direction as the second gripper (10). Ru. In addition,
In this first gripping body (9) as well, a sensor such as a thermocouple is used for temperature control so that the amount of warpage is maintained at a predetermined value similarly to the second gripping body.

The operation of the above configuration will be explained next. Figure 4 shows substrates (7a) to (7n) with a diameter of 4 inches pulled out from the processing furnace and placed on the board at approximately 4.81 pitches. The amount of deformation expressed by arrow height is 0.5 to 1.0 II on average
In some cases, it may be deformed by about 2 mm.

A gripping device (9) is moved to a predetermined position by a robot arm or the like, and a gripping operation is started for these substrate groups. In the gripping operation, for example, the amount of deformation d is 1. Oma+ board (7
As shown in FIG. (not shown) and is input to the discrimination circuit (17). Since the board (7a) has an arcuate cross section, the detection value of the optical sensor 1 is calculated as being larger than the detection value of the optical sensor 2, and the discrimination circuit (17) sends the comparator (19) as a (+) signal. ) is input. The comparator (19) compares the set value and the calculated detection value, and sends the difference signal to the A/D converter (20).

A (+) displacement command signal is output from the A/D converter (20). This displacement command signal energizes the heater 1 (14a), energizes the heater (3 or 4) selected to warp in the same direction on the first gripping body (9) side, and further energizes the opening/closing control unit ( 22). This opening/closing control section (2
In 2), the opening/closing operation is performed based on the detected value of the optical sensor 1 (13a). That is, in the above example, the substrate (7
Although the distance between the tip of a) and the optical sensor 1 (13a) is actually 2 mm, the amount of deformation is detected as l■, and the second gripping body (10) is deformed along the substrate (7a). In this case, the heating temperature due to energization, that is, the temperature difference, is approximately 23
temperature is calculated and controlled to maintain this temperature. With the above control operation, as shown in FIG. 6, the deformed substrate is also deformed so that the second gripping body (10) follows the deformation,
At the same time, the first gripping body (9) was also warped and deformed in the same way, so that the substrate was reliably gripped by the claws (3c).

In addition, in the above embodiment, an example of the substrate deformed so that there is a gap between the optical sensor 1 (13a) and the optical sensor 1 (13a) was explained.
(13a) is slightly deformed so that the gap with optical sensor 2 (13b) opens, optical sensor 2 (Hb)
Based on the detected value of the second gripper (
10) is controlled. Moreover, although the three-layer structure is used for deformation, it may be made to have a two-layer structure so that only one side is warped.

[Effects of the Invention] Gripping became reliable and falling accidents during transportation were eliminated, contributing to improved productivity and yield.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing one embodiment of the present invention, and Fig. 2 is a plan view showing an embodiment of the present invention.
FIG. 3 is a block diagram showing the control circuit, FIG. 4 is a sectional view showing the substrate on the board after heat treatment, and FIG. 5 is a diagram showing the gripping state before deformation control. , FIG. 6 is a diagram showing the end state after deformation control, and FIG. 7 is a plan view showing a conventional example. (3a), (3B>, (3c)...Claw part (4)...
First gripping body (10)...Second gripping body (11), (12a), (12b) --, member (13
a) Competition... Optical sensor 1 (13b)... ψ optical sensor 2 (tea)... Heater 1 (heating part) (14b)
... Heater 2 (heating section) (te) ... Control circuit section (
Control means) Figure 1 Figure 2 Figure 3 114 rA

Claims (1)

[Claims] A first support member supporting at least two points on the outer side of the thin plate member.
a second gripping body that supports at least three points on the outer side of the thin plate-like member with the first gripping body; and at least one of the first and second gripping bodies has a coefficient of thermal expansion. A laminate of a plurality of different metals is formed, and a gap between a heating section provided on the laminate and the thin plate member provided on at least one of the first and second gripping bodies during a gripping operation is detected. A gripping device comprising: a sensor; and a control means for controlling the heating section using a signal from the sensor to control the amount of warpage of the first and second gripping bodies.