Electrostatic Pick Transfer Arm for Semiconductor Wafer Handling
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Solution Overview
Problem
Conventional multi-joint transfer devices in plasma processing apparatuses face limitations in rotational angle due to cable constraints, leading to reduced durability and increased transfer time, as well as complexity in joint configurations.
Innovation Solution
A transfer device with an electrostatic pick and a control method that allows the internal electrode to be electrically floating, enabling unrestricted rotational angles while maintaining the transfer object on the pick, eliminating the need for cables at joint units and enhancing durability by avoiding cable insertion through joints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cable is provided through the joint unit to supply power to the electrostatic attracting device, then the electrostatic pick can hold the transfer target object, but the rotational angle of the arm member is limited and the cable durability is reduced due to repeated bending
Solution Approach 1:
The patent removes the cable from the joint unit configuration. Instead of routing the cable through the rotating joint, the electrostatic pick is designed to operate without requiring a continuous cable connection during rotation. The cable is only connected when the arm is in the retracted position, eliminating the cable bending and durability issues while maintaining full rotational freedom.
Solution Approach 2:
The patent implements preliminary connection of the cable to the electrostatic pick before the arm member rotates. The cable is connected in advance when the arm is retracted, and the connection is maintained throughout the rotation without requiring the cable to bend at the joint. This preliminary setup eliminates the need for repeated cable bending during operation.
2Strength
If extra length of cable is secured at each joint unit to prevent cable cutting, then the cable will not be cut during maximum arm bending, but the rotational angle is limited and transfer time increases
Solution Approach 1:
The patent eliminates the need for extra cable length compensation mechanisms by removing the cable from the joint unit entirely. The cable is only present and connected when the arm is in the retracted position, not during the transfer operation. This eliminates both the cable integrity concerns and the time loss associated with limited rotational angles.
3Ease of manufacture
If the cable is routed through the joint unit, then power can be supplied to the electrostatic attracting device, but the joint configuration becomes complex and durability is reduced
Solution Approach 1:
The patent simplifies the joint unit configuration by completely removing the cable routing through the joint. The electrostatic pick operates without a cable during rotation, and the cable is only connected when the arm is retracted. This eliminates the complex cable management requirements and improves both manufacturing simplicity and cable durability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for unencumbered transfer operations with improved durability and reduced transfer time, as well as a more compact joint design, enhancing the efficiency and reliability of the transfer process.
Implementation Method 1
an electrostatic attracting device, including an internal electrode provided in the pick, configured to attract and hold the transfer target object on the pick electrostatically
Implementation Method 2
By controlling the electrostatic attracting device and the driving device, the control device is configured to turn the internal electrode into an electrically floating state after the transfer target object is electrostatically attracted to and held on the pick
Data Source
AI summary
A transfer device can have a high durability and no limit in an operation of an arm member. An electrostatic pick 44 of a first transfer device 17 is advanced into a process module 12, and a wafer W is electrostatically attracted to and held on the electrostatic pick 44. While the wafer W is being transferred into a load lock module 14 by driving the first transfer device 17, the electrostatic pick 44 is turned into an electrically floating state, so that a state in which the wafer W is electrostatically attracted to and held on the electrostatic pick 44 is maintained. After the transferring of the wafer W to the load lock module 14 is completed, charges of the electrostatic pick 44 are neutralized, so that the wafer W is not electrostatically attracted to and held on the electrostatic pick 44.