JPH0966486A - Substrame conveying arm and conveying method using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the length of an arm relative to the conveying distance of a substrate by a high rigidity closed chain mechanism in a revolute joint type robot having few sliding portions and is liable to prevent impurities from spatter. SOLUTION: Six arms form a closed link mechanism and the rotary revolute joint 11, 12, 13, 14, 15, 16 are parallel to each other. The sum of the lengths of 3 arms of the arm fixed to a base and adjacent arms is equalized to the sum of the lengths of the other 3 arms. The lengths of the arms are equalized symmetrically left and right about the arm fixed to the base. Since a motor fixed to the base extends through the center of another motor, 2 arms can be independently driven. By using a high rigidity closed chain mechanism capable of passing through a characteristic point of the closed link mechanism, a conveying distance can be prolonged relative to the length of the arm, so that a substrate conveying arm having a small external form and capable of conveying the substrate with high speed can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate transfer arm for transferring a substrate in a clean environment, and in particular, vibration is small,
The present invention also relates to a substrate transfer arm that transfers a substrate at a high speed and in a wider range.

[0002]

2. Description of the Related Art In order to efficiently use a processing apparatus for forming a thin film on a substrate, it is necessary for the apparatus for transferring the substrate to the processing apparatus to move at high speed. However, in this process, contamination of impurities should be avoided as much as possible.
Therefore, an articulated robot, which has few sliding parts and is easy to prevent scattering of impurities, is used for transporting the substrate.
As the articulated robot, a scalar type two-axis robot that uses a belt for power transmission shown in FIG. 6 and a frog leg type two-axis robot that uses a link mechanism for power transmission shown in FIG. 7 are known. ing.

[0003]

The above-mentioned SCARA type robot has an advantage that the arm length can be shortened with respect to the transport distance. However, the open chain mechanism supports only one side, and there is a problem that the rigidity cannot be increased because the belt is used for transmitting power.

On the other hand, the frog leg type robot is
Since it is a closed chain mechanism and a link mechanism can be used for power transmission, there is an advantage that rigidity can be increased. But,
From the state shown in FIG. 8 to the state shown in FIG. 7, the second
The transport distance can be obtained only up to the sum of the arm length L2 and the third arm length L3. Therefore, the scalar type 2 shown in FIG.
There is a problem that the arm length has to be almost doubled with respect to the axis robot even with the same transport distance.

The present invention has been made to solve the above problems, and an object of the present invention is to use a closed chain mechanism having high rigidity and to shorten the arm length with respect to the transport distance. Thus, it is an object of the present invention to provide a substrate transfer arm having a structure capable of realizing two closed chain mechanisms with one arm.

[0006]

Therefore, according to the present invention, the first arm fixed to the base is sequentially connected by the rotary shaft.
With a closed chain mechanism composed of book arms, in a substrate transfer arm for loading and transferring substrates by a transfer hand attached to the fourth arm, all rotation axes are parallel to each other, and The sum of the lengths of the second arm and the sixth arm was made equal to the sum of the length of the third arm, the fourth arm, and the fifth arm.

In the above-described substrate transfer arm, the second arm and the sixth arm have the same length, the third arm and the fifth arm have the same length, and the angle formed by the third arm and the fourth arm, The angles formed by the 4th arm and the 5th arm were made equal.

In the above-mentioned substrate transfer arm, the second arm and the sixth arm have the same length, the third arm and the fifth arm have the same length, and the first arm has a length of zero. Third arm and fourth
The angle formed by the arms is made equal to the angle formed by the fourth and fifth arms, and the rotation axis of the second arm connected to the first arm and the first arm connected to the first arm are on the same axis. The second arm is driven by the first actuator fixed to the first arm on the rotation axes of the six arms,
The sixth arm is driven by the shaft that penetrates the first actuator and is connected to the second actuator fixed to the first arm.

Further, in the above-mentioned substrate transfer arm, a belt mechanism is incorporated so that the second arm and the fifth arm move substantially in parallel.

Further, in the above-mentioned substrate transfer arm, a rotation drive mechanism is added to the rotary shaft connecting the fifth arm and the sixth arm.

[0011]

According to the present invention, the substrate attached to the fourth arm is transferred by the closed chain mechanism composed of the six arms connected by the rotary joint in order from the first arm fixed to the base. In a substrate transfer arm for transferring a substrate with a hand, all rotation axes are parallel to each other, the sum of the lengths of the first arm, the second arm, and the sixth arm, and the third arm, the fourth arm, and the fifth arm. By making the sum of the lengths of all equal, it is possible to arrange all the rotation axes on the same plane, and it is possible to smoothly transition between two closed chain states, and it is possible to double the transport distance. become.

Further, in the above-mentioned substrate transfer arm, the second arm and the sixth arm have the same length, the third arm and the fifth arm have the same length, and the angle formed by the third arm and the fourth arm, Since the angles formed by the fourth arm and the fifth arm are equalized, the second arm and the sixth arm connected to the first arm are rotated in the opposite directions at the same speed, so that the substrate transfer hand can be used. It is possible to linearly move the attached fourth arm while keeping the posture constant.

In the above-described substrate transfer arm, the second arm and the sixth arm have the same length, the third arm and the fifth arm have the same length, and the first arm has a length of zero. Third arm and fourth
The angle formed by the arms is made equal to the angle formed by the fourth and fifth arms, and the rotation axis of the second arm connected to the first arm and the first arm connected to the first arm are on the same axis. The second arm is driven by the first actuator fixed to the first arm on the rotation axes of the six arms,
Since the sixth arm is driven by the shaft that penetrates the first actuator and is connected to the second actuator fixed to the first arm, the first and second actuators can drive the sixth arm with respect to the first arm. By rotating the second arm and the sixth arm in the same direction at the same speed, it is possible to infinitely rotate the fourth arm to which the substrate transfer hand is attached with respect to the first arm, and rotate in the opposite direction at the same speed. By doing so, the fourth arm can be linearly moved with respect to the first arm while keeping the posture constant. Therefore, it is possible to select the shortest movement path that does not exceed half a circle for the rotational movement between the two points, and the rotational movement can be performed in the shortest time.

The following relates to a method for solving the problem of how to pass through the singularity of this closed loop mechanism.

In the above-mentioned substrate transfer arm, a belt mechanism is incorporated so that the second arm and the fifth arm move substantially parallel to each other. It becomes possible to smoothly transition to a specific one of the closed chain states of.

Further, in the above-mentioned substrate transfer arm, by adding a rotary drive mechanism to the rotary shaft connecting the second arm and the third arm, two rotary shafts are arranged on the same plane. It becomes possible to smoothly transition to a specific one of the next closed chain states.

[0017]

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

FIG. 1 is a top view showing a substrate transfer arm according to an embodiment of the present invention, and FIG. 2 is an explanatory view for explaining the dimensions and angular relationship of a substrate transfer arm according to another embodiment of the present invention. 3 is a front sectional view of a substrate transfer arm according to a third embodiment of the present invention, FIG. 4 is a front sectional view showing a mechanism for passing a singular point of a closed loop mechanism of the present invention, and FIG. 5 is a sectional view of the present invention. It is a front sectional view showing another mechanism for passing a singular point of a closed loop mechanism.

In FIG. 1, the substrate transfer arm is composed of six arms. The second arm 2 is connected to the first arm 1 fixed to the base via a first joint 11 which is a rotational pair. A third arm 3 is connected to the second arm 2 via a second joint 12 that is a rotational pair. Further, a fourth arm 4 is connected to the third arm 3 via a third joint 13, which is a rotating pair. Similarly, the fifth arm 5 is connected to the fourth arm 4 via a fourth joint 14 which is a rotational pair.
Similarly, a sixth arm 6 is connected to the fifth arm 5 via a fifth joint 15 which is a rotational pair. Similarly, the first arm 1 is connected to the sixth arm 6 via a sixth joint 16 which is a rotational pair, and forms a closed chain mechanism. The fourth arm 4 is the substrate 2
This is the hand to transfer 1. All axes of rotation are parallel to each other. The first joint 11 and the sixth joint 1 on the first arm 1
The straight line distance of 6 is L1. This will be referred to as the length of the first arm 1. Similarly, the lengths of the second arm 2 to the sixth arm 6 are L2 to L6. Here, the sum of L1, L2, and L6 is made equal to the sum of L3, L4, and L5. Then, all the rotation axes can be arranged on the same plane, the two closed chain states can be smoothly moved, and the transport distance can be almost twice the sum of L2 and L3. If it is not possible to arrange all the rotation axes on the same plane, as shown in FIG. 8, the transport distances are almost L2 and L3.
Is only the sum of

In FIG. 2, the substrate transfer arm is basically the same as that in FIG. 1 described above. First as shown in the figure
The rotation angles of the joint 11 to the sixth joint 16 are set to θ1 to θ6.
And The lengths L2 and L6 of the second arm 2 and the sixth arm 6 are made equal, the lengths L3 and L5 of the third arm 3 and the fifth arm 5 are made equal, and rotation of the third joint 13 is performed. The gear 3c was fixed to the third arm 3 and the gear 5c having the same size and the same number of teeth as the gear 3c was fixed to the fifth arm 5 so that the angle θ3 and the rotation angle θ4 of the fourth joint 14 became equal. This is different from FIG. By doing so, the actuator that rotationally drives the second arm 2 attached to the first arm 1 and the actuator that rotationally drives the sixth arm 6 are the hands that transfer the substrate 21 to the fourth arm.
It is possible to move the arm 4 linearly. The joint angle of the actuator that rotationally drives the second arm 2 is θ1, and the joint angle of the actuator that rotationally drives the sixth arm 6 is −θ6. When the actuators are driven so that θ1 and θ6 are equal, that is, when both actuators are rotated in the opposite directions at the same speed, the fourth arm 4, which is a hand for transferring the substrate 21, moves to the first arm.
Moves linearly with respect to arm 1.

In FIG. 3, the substrate transfer arm is basically the same as that shown in FIG. First as shown in the figure
The rotation angles of the joint 11 to the sixth joint 16 are set to θ1 to θ6.
And The lengths L2 and L6 of the second arm 2 and the sixth arm 6 are made equal, the lengths L3 and L5 of the third arm 3 and the fifth arm 5 are made equal, and rotation of the third joint 13 is performed. The gear 3c was fixed to the third arm 3 and the gear 5c having the same size and the same number of teeth as the gear 3c was fixed to the fifth arm 5 so that the angle θ3 and the rotation angle θ4 of the fourth joint 14 became equal. This is different from FIG. The length L1 of the first arm 1 is zero. That is, the first
The joint 11 and the sixth joint 11 are aligned on the same axis. The first joint 11 of the second arm 2 connected to the first arm 1 and the sixth joint 16 of the sixth arm 6 connected to the first arm 1 are fixed to the first arm 1 by a motor stator 2a and a motor rotor 2b. And the shaft 2c connected to the motor rotor 2b drives the second arm 2, and the shaft 6c connected to the motor stator 6a fixed to the first arm 1 and the motor rotor 6b and the motor rotor 6b passes through the motor rotor 2b to move the sixth arm 6 I tried to drive.
By doing so, the actuator for rotating the second arm 2 attached to the first arm 1 and the actuator for rotating the sixth arm 6 rotate the fourth arm 4, which is a hand for transferring the substrate 21, linearly. It becomes possible to rotate and move. Let θ be the joint angle of the actuator that rotationally drives the second arm 2.
1. The joint angle of the actuator that rotationally drives the sixth arm 6 is −θ6. When the actuators are driven so that θ1 and θ6 are equal, that is, when both actuators are rotated in opposite directions at the same speed, the fourth arm 4, which is the hand on which the substrate 21 is transferred, moves linearly. When driving is performed so that the sum of θ1 and θ6 becomes zero, that is, when both actuators are rotated in the same direction and at the same speed, the fourth arm 4, which is the hand on which the substrate 21 is transferred, rotationally moves.

As described above, the second arm connected to the first arm 1
The first joint 11 of the arm 2 and the sixth joint 16 of the sixth arm 6 connected to the first arm 1 are connected to the motor stator 2a fixed to the first arm 1, the motor rotor 2b, and the shaft 2c connecting to the motor rotor 2b. A shaft 6 that drives the second arm 2 and is connected to the motor stator 6a, the motor rotor 6b, and the motor rotor 6b fixed to the first arm 1 and that penetrates the motor rotor 2b.
Since the sixth arm 6 is driven by c, the second arm 2 and the sixth arm 6 are rotated with respect to the first arm 1 in the same direction at the same speed, so that the substrate is moved with respect to the first arm 1. It becomes possible to rotate the fourth arm 4 to which the transfer hand is attached infinitely. Therefore, it is possible to select the shortest movement path that does not exceed half a circle for the rotational movement between the two points, and the rotational movement can be performed in the shortest time.

A method of solving the problem of how to pass through the singularity of the closed loop mechanism will be described below.

First, referring to FIG. 4, in the substrate transfer arm described above, a belt mechanism is incorporated so that the second arm 2 and the fifth arm 5 move substantially parallel to each other, so that all rotation axes are aligned on the same plane. It will be explained that it becomes possible to smoothly shift from one state to a specific one of the next two closed chain states.

In the figure, the substrate transfer arm is basically the same as that shown in FIG. Shaft 6 for driving the sixth arm 6
The pulley 6d is fixed to c, the pulley 3d is fixed to the shaft 3a fixed to the third arm 3, and the pulley 6d and the pulley 3d are fixed.
Are linked by a belt 31, and the sixth arm 6 and the third arm 3 move substantially parallel to each other. Since the length L2 of the second arm 2 and the length L3 of the third arm 3 are different and the length L4 of the fourth arm 4 is not zero, the sixth arm 6 and the third arm 3 are not accurate. It is not parallel. Therefore, the diameter of the pulley 6d and the diameter of the pulley 3d are not the same. To make the belt stretch when all the rotation axes are lined up on the same plane,
Other than that, I try to loosen it gradually. By doing so, it becomes possible to move the state in which all the rotation axes are arranged on the same plane as a mirror object. As a result, the fourth
The motion range of the linear motion of the arm is approximately (L2 + L3) × 2.

Next, referring to FIG. 5, in the above-described substrate transfer arm, a rotation drive mechanism is added to the second joint 12 that connects the second arm 2 and the third arm 3 so that all rotation axes are in the same plane. It will be described that it becomes possible to smoothly transition from the state arranged side by side to one specific state of the next two closed chain states.

In the figure, the substrate transfer arm is basically the same as that shown in FIG. Shaft 6 for driving the sixth arm 6
The pulley 6d is fixed to c, the pulley 3d is fixed to the shaft 3a fixed to the third arm 3, and the pulley 6d and the pulley 3d are fixed.
Are linked by a belt 31, and the sixth arm 6 and the third arm 3 move substantially parallel to each other. Since the length L2 of the second arm 2 and the length L3 of the third arm 3 are different and the length L4 of the fourth arm 4 is not zero, the sixth arm 6 and the third arm 3 are not accurate. It is not parallel. Therefore, the diameter of the pulley 6d and the diameter of the pulley 3d are not the same. The belt is designed to be fully extended when all the rotating shafts are aligned on the same plane. By doing so, it becomes possible to move the state in which all the rotation axes are arranged on the same plane as a mirror object. As a result, the operation range of the linear movement of the fourth arm is approximately (L2 + L3) × 2.

In FIG. 5, the substrate transfer arm is basically the same as that shown in FIG. First as shown in the figure
The rotation angles of the joint 11 to the sixth joint 16 are set to θ1 to θ6.
And The lengths L2 and L6 of the second arm 2 and the sixth arm 6 are made equal, the lengths L3 and L5 of the third arm 3 and the fifth arm 5 are made equal, and rotation of the third joint 13 is performed. The gear 3c is fixed to the third arm 3 and the gear 5c having the same size and the same number of teeth as the gear 3c is fixed to the fifth arm 5 so that the angle θ3 and the rotation angle θ4 of the fourth joint 14 become equal. This is different from FIG. The length L1 of the first arm 1 is zero. That is, the first
The joint 11 and the sixth joint 11 are aligned on the same axis. The first joint 11 of the second arm 2 connected to the first arm 1 and the second joint 12 of the third arm 3 connected to the second arm 2 are fixed to the first arm 1 by a motor stator 2a and a motor rotor 2b. A second arm 2 driven by a shaft 2c connected to the motor rotor 2b, a motor stator 3a fixed to the first arm 1, a motor rotor 3b, and a pulley 3e fixed to a shaft 3c penetrating the motor rotor 2b. The third arm 3 is driven via the belt 31 hung between the pulleys 3d fixed to the shaft 3a fixed to the third arm. By doing so, the actuator for rotating and driving the second arm 2 attached to the first arm 1 and the actuator for rotating and driving the third arm 3 can linearly move the fourth arm 4 which is a hand for transferring the substrate 21. It becomes possible to rotate and move. The joint angle of the actuator that rotationally drives the second arm 2 is θ1, the rotational angle of the shaft 3c of the actuator that rotationally drives the third arm 3 is θ0, and the angle of the second joint 12 is θ2. The difference between θ0 and θ1 is θ2. θ1 and θ
When 2 is driven so as to satisfy the relationship of L2 × cos θ1 = L3 × cos (θ1 + θ2), the fourth arm 4, which is a hand for transferring the substrate 21, linearly moves. When the actuators are driven so that θ1 and θ0 are equal, that is, when both actuators are rotated in the same direction and at the same speed, the fourth arm 4, which is a hand on which the substrate 21 is transferred, rotationally moves. By doing so, it becomes possible to move the state in which all the rotation axes are arranged on the same plane as a mirror object. Accordingly, the motion range of the linear motion of the fourth arm is approximately (L2 + L3) × 2.
Becomes

Further, as shown in FIG. 9, the stage 23 on which the substrate 21 is placed is stopped on the line 22 for carrying the substrate 21 (this point is hereinafter referred to as a station), and in this stopped state, the station Arm 2, next to
The substrates 3, 5 and 6 are extended to receive the substrate 21 on the stage 23 and placed on the fourth arm 4. And the arms 2, 3,
The fifth arm 6 is contracted to move the fourth arm 4 on which the substrate 21 is placed. Then, the arms 2, 3, 5, 6 are further extended, the substrate 21 is passed to the processing device 24, and is processed by the peripheral device 25 and the like.

By using the substrate transfer arm of the present invention as described above, the substrate transfer system can be made compact.

Further, here, the description is given of the transfer of the substrate to the processing apparatus from the substrate transfer line, but it is naturally applicable to transfer from the apparatus to the apparatus.

[0032]

As described above, according to the present invention, the closed chain mechanism having high rigidity is used so that the carrying distance can be increased with respect to the length of the arm. It is possible to obtain a substrate transfer arm capable of high-speed transfer. Further, since the structure is such that the rotational movement can be performed infinitely, it is possible to obtain the substrate transfer arm which can rotationally move in the shortest time.

[Brief description of drawings]

FIG. 1 is a top view showing a substrate transfer arm according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining a dimension and an angular relationship of a substrate transfer arm according to another embodiment of the present invention.

FIG. 3 is a front sectional view of a substrate transfer arm according to a third embodiment of the present invention.

FIG. 4 is a front sectional view showing a mechanism for passing a singular point of the closed loop mechanism of the present invention.

FIG. 5 is a front sectional view showing another mechanism for passing a singular point of the closed loop mechanism of the present invention.

FIG. 6 is a top view showing a conventional substrate transfer arm.

FIG. 7 is a top view showing another conventional substrate transfer arm.

FIG. 8 is a top view showing an operation range of another conventional substrate transfer arm.

FIG. 9 is a diagram of a transfer system using the substrate transfer arm of the present invention.

[Explanation of symbols]

1 ... Arm 1 ... Arm 2 ... Arm 2a ... Motor stator 2b ... Motor rotor 2c ... Shaft 3 ... Arm 3a ... Shaft 3b ………
Gear fixing plate, 3c ......... Gear, 3d ... Pulley, 3e
……… Pulley, 3f ……… Shaft, 3g ……… Motor rotor, 3h ……… Motor stator, 4 ……… 4th arm,
5 ... Arm 5, 5a ... Shaft, 5b ... Gear fixing plate, 5c ... Gear, 6 ... Arm 6, 6a ...
Motor stator, 6b ......... Motor rotor, 6c ....
Shaft, 6d ......... Pulley, 11 ......... First joint, 1
2 ... 2nd joint, 13 ... 3rd joint, 14 ... 4th joint, 15 ... 5th joint, 16 ... 6th joint, 2
1 ... substrate, 31 ... belt

Claims (6)

[Claims] 1. A first arm fixed to a base is connected to a second arm via a rotation shaft, a second arm is connected to a third arm via a rotation shaft, and a rotation shaft is connected to the third arm. The fourth arm is connected to the fourth arm, the fifth arm is connected to the fourth arm via a rotary shaft, the sixth arm is connected to the fifth arm via a rotary shaft, and the sixth arm is rotated. In the substrate transfer arm that connects the first arm fixed to the base via an axis to form a closed chain and loads and transfers the substrate on the hand attached to the fourth arm, all rotations are performed. The axes are parallel to each other, and the sum of the lengths of the first arm, the second arm, and the sixth arm and the sum of the lengths of the third arm, the fourth arm, and the fifth arm are made substantially equal. A substrate transfer arm characterized by the above. 2. The substrate transfer arm according to claim 1, wherein the second arm and the sixth arm have substantially the same length, and
Making the lengths of the third arm and the fifth arm substantially equal to each other, and
A substrate transfer arm, wherein an angle formed by the third arm and the fourth arm and an angle formed by the fourth arm and the fifth arm are substantially equal to each other. 3. The substrate transfer arm according to claim 1, wherein the second arm and the sixth arm have substantially equal lengths, and the third arm and the fifth arm have substantially equal lengths, The length of the first arm is substantially zero, and the angle formed by the third arm and the fourth arm is substantially equal to the angle formed by the fourth arm and the fifth arm, and the same. The axis of rotation of the second arm connected to the first arm and the axis of rotation of the sixth arm connected to the first arm are axially fixed by a first actuator fixed to the first arm. A substrate transfer characterized in that the second arm is driven, and the sixth arm is driven by a shaft that penetrates the first actuator and is connected to a second actuator fixed to the first arm. arm. 4. The substrate transfer arm according to claim 3, wherein a belt mechanism is configured so that the second arm and the fifth arm move substantially parallel to each other. 5. The substrate transfer arm according to claim 3, wherein a rotation drive mechanism is added to a rotation shaft connecting the fifth arm and the sixth arm. 6. A first station for stopping the substrate at a predetermined position on a line for transferring the substrate, and an arm extending to the first station with respect to the substrate at the stopped position, the substrate to be transferred. , The arm is contracted, the transferred substrate is moved, the arm is further extended, the substrate is transferred to a second position different from the first station, and processing is performed at the second position. A method for carrying a substrate, comprising: