Double arm substrate transport unit

• US 20020066330A1
• Filed: 11/16/2001
• Published: 06/06/2002
• Est. Priority Date: 11/17/2000
• Status: Active Grant

• Current Assignee: Tazmo Co., Ltd.
• Original Assignee: Tazmo Co., Ltd.
• Inventors: Namba, Hirotoshi, Kobiki, Takahiro
• Granted Patent: US 6,669,434 B2
• Time in Patent Office: Days
• US Class Current: 74/490.01
• CPC Class Codes: B25J 9/042 comprising an articulated arm
• CPC Class Codes: H01L 21/67742 Mechanical parts of transfer devices robots in general in B25J
• CPC Class Codes: Y10T 74/20305 Robotic arm

Abstract

A double arm substrate transport unit for transporting a work piece, such as a semiconductor wafer, is provided of which the robotic arm is formed of a first forearm supported by the tip part of a base arm so as to be freely rotatable, a first end effector that is supported by the tip part of the first forearm so as to be freely rotatable and on which a work piece is placed, a second forearm that is supported by the tip part of the base arm so as to be freely rotatable and that is attached above the first forearm so as to overlap the first forearm and a second end effector that is supported by the tip part of the second forearm so as to be freely rotatable and on which a work piece is placed. Thereby, the U-shaped bar that is required by a conventional unit becomes unnecessary and the number of components is reduced so that the unit is made compact and so that a reduction in weight is achieved in comparison with a conventional unit that has two base arms, one on the right and the other on the left and, in addition, the mechanical rigidity is maintained at a high level while the transport distance is made great.

Claims

1. A double arm substrate transport unit for transporting a work piece such as a semiconductor wafer, a substrate for a photomask or a glass substrate for a liquid crystal display by using a robotic hand, characterized by the robotic hand comprising:

a base arm supported by a base so as to be freely rotatable;

a first forearm supported by the tip part of the above base arm so as to be freely rotatable;

a first end effector supported by the tip part of the first forearm so as to be freely rotatable on which a work piece is placed;

a second forearm supported by the tip part of the base arm so as to be freely rotatable that is attached above the first forearm; and

a second end effector supported by the tip part of the second forearm so as to be freely rotatable, on which a work piece is placed.

2. The double arm substrate transport unit according to claim 1, characterized in that the first forearm and the second forearm have the same arm length, share a common rotational axis above the base arm and are independently rotatable in planes at different height positions.

3. The double arm substrate transport unit according to claim 2, characterized by having three independent motors within the base placed in the lower portion of the unit,

wherein the first motor is provided so as to rotate a first support rod that becomes the rotational axis of the base arm,

wherein the second motor is provided so as to rotate a second support rod provided having the same axis as the rotational axis of the base arm so that the torque is conveyed to a fourth support rod integrally fixed to the second forearm via a first transmission means provided within the base arm and, thereby, rotates the second forearm, the fourth support rod being provided within a fifth support rod that is hollow, that has the same axis as the rotational axis of the second forearm and that is fixed to the base arm so as to be unrotatable,

wherein the third motor is provided so as to rotate a third support rod provided within the second support rod so that the torque is conveyed to a sixth support rod integrally fixed to the first forearm via a second transmission means provided within the base arm and, thereby, rotates the first forearm, the sixth support rod having the same axis as the rotational axis of the first and second forearms,

wherein a third transmission means is provided within the first forearm so that the fifth support rod that is hollow and the rotational axis of the first end effector convey rotations of which the rotational speed ratio is 1:

2, the fifth support rod that is hollow being provided at the tip part of the base arm so as to have the same axis as the rotational axis of the first and second forearms in order to have the fourth support rod as the center,

wherein a fourth transmission means is provided within the second forearm so that the fifth support rod that is hollow and the rotational axis of the second end effector convey rotations of which the rotational speed ratio is 1;

2.

4. The double arm substrate transport unit according to claim 3, characterized by comprising a means for controlling the first, second and third motors,

wherein the control means

rotates and synchronizes the first and second motors in the same direction and

rotates the third motor in the direction opposite to the direction in which the first and second motors rotate at the same rotational speed as that of the first and second motors and,

thereby, a work piece placed on the tip of the first end effector translates in a direction radiating from the base arm rotational axis and, at the same time, a work piece placed on the tip of the second end effector moves around a circle of which the center is on the base arm rotational axis so as to be transported in a direction radiated from the base arm rotational axis.

5. The double arm substrate transport unit according to claim 3, characterized by comprising a means for controlling the first, second and third motors,

wherein the control means

rotates and synchronizes the first and third motors in the same direction and

rotates the second motor in the direction opposite to the direction in which the first and third motors rotate at the same rotational speed as that of the first and third motors and,

thereby, a work piece placed on the tip of the second end effector translates in a direction radiating from the base arm rotational axis and, at the same time, a work piece placed on the tip of the first end effector moves around a circle of which the center is on the base arm rotational axis so as to be transported in a direction radiated from the base arm rotational axis.

6. The double arm substrate transport unit according to claim 3, characterized by comprising a means for controlling the first, second and third motors,

wherein the control means rotates and synchronizes the first, second and third motors in the same direction and, thereby, the first and second end effectors become rotatable in an arbitrary rotational direction having the base arm rotational axis as the center while maintaining the angles formed by the base arm and the first and second forearms.

7. The double arm substrate transport unit according to claim 3, characterized by comprising a means for controlling the first, second and third motors,

wherein the control means controls the first motor and the second or third motor to rotate in an asynchronous manner and, thereby, a work piece placed on the first end effector or the second end effector is moved to a targeted transport position through an arbitrary track.

8. The double arm substrate transport unit according to claim 3, characterized by comprising a means for controlling the first, second and third motors,

wherein the control means controls the second and the third motors to synchronize and to rotate in the same direction and controls the first motor to rotate in the direction opposite to the direction in which the second and the third motors rotate or in an asynchronous manner with the rotation of the second and third motors and, thereby, a work piece placed on the first end effector and a work piece placed on the second end effector are transported through the same track in different planes.

9. The double arm substrate transport unit according to claim 2, characterized by comprising motors connected to the rotational axes of respective arms and the end effectors.