Robot End Effector Plate Member for Wafer Positioning
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Solution Overview
Problem
Existing methods for instructing robots to accurately position large semiconductor wafers or glass substrates in a vertical direction are challenging due to deformation of the end effector and generation of unwanted particles, leading to reduced accuracy and potential damage from reaction forces.
Innovation Solution
A robot system with a holding unit, such as a vacuum suction unit or edge grip, and a control unit that lowers the end effector to detect the plate member's position without direct contact, using a holding-state detection unit to determine if the plate is held, allowing for accurate placement without deformation or particle generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the end effector is contacted with the target to detect position, then the target position can be detected, but the end effector and/or target may be deformed and unwanted particles may be generated
Solution Approach 1:
A plate member is introduced as an intermediary between the end effector and the target. The end effector contacts the plate member instead of directly contacting the target, thereby preventing deformation and particle generation while still enabling position detection through the plate member's movement
Solution Approach 2:
The plate member serves as a temporary copy or substitute for the target during the position detection process. By detecting the position through the plate member's interaction with the end effector, the system obtains target position information without direct contact between the end effector and target
2Object-affected harmful factors
If the robot is moved at a very low speed to avoid deformation and particle generation, then harmful effects are reduced, but accuracy of positional detection is significantly deteriorated
Solution Approach 1:
The plate member acts as a mediator that allows high-speed operation without direct contact between the end effector and target. This intermediary enables the system to maintain high detection accuracy while operating at high speeds, as the plate member absorbs the interaction forces
3Strength
If the end effector is made thicker to resist deformation from reaction force, then structural strength is improved, but the end effector cannot be applied to wafer cassette based on SEMI standard
Solution Approach 1:
The plate member serves as an intermediary that bears the reaction force from target contact, allowing the end effector to maintain its thin profile compatible with SEMI standards while still achieving the necessary structural strength through the plate member's support
Solution Approach 2:
The system is segmented into the end effector, plate member, and target components. The plate member is separated from both the end effector and target, allowing each component to be optimized independently - the end effector for thin profile compatibility and the plate member for structural strength
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 method enables high-accuracy detection and placement of the target position in the vertical direction, preventing end effector deformation and avoiding unwanted particles, thereby improving the precision and reliability of the robot's instruction process.
Implementation Method 1
The holding unit has vacuum suction unit configured to suck the plate member
Data Source
Figure 1
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Figure 5
AI summary
A robot control unit (40) related to the present invention is configured to turn off a holding unit (60) for a plate member (50), while the plate member (50) is placed on an end effector (25), and lower the end effector (25), by a predetermined distance, from an initial position higher than a preset temporary placing position toward the temporary placing position. Then the robot control unit (40) switches the holding member (60), from an OFF state to an ON state, while the end effector (25) is stopped, and determines whether or not the plate member (50) is held by the holding unit (60), by using a holding-state detection unit (63). When the plate member (50) is determined to be held by the holding unit (60), the robot control unit (40) will turn off the holding unit (60) while further lowering the end effector (25) by the predetermined distance. Meanwhile, when the plate member (50) is determined not to be held by the holding unit (60), the robot control unit (40) will detect a position of the end effector (25) at this point of time, as a normal placing position.