Wafer Edge Protection Torque Limit Mechanism
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Solution Overview
Problem
Existing wafer edge protection apparatuses in photolithography tools lack collision protection mechanisms, leading to potential damage to wafers and equipment during rapid movements, as they cannot prevent or mitigate the impact of collisions effectively.
Innovation Solution
A wafer edge protection apparatus with an electrical control module and a vertical motion mechanism, featuring a shaft coupler, transmission sleeve, and compressible springs that disengage upon exceeding torque limits, preventing rotational motion transfer and automatically stopping the servomotor to prevent overload, thus providing collision protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wafer edge protection apparatus operates without collision protection mechanism, then the device complexity is reduced, but the reliability deteriorates due to potential damage from collisions during rapid movements
Solution Approach 1:
The patent implements a torque limit mechanism that预先 sets a safe operating threshold for the servomotor. When collision occurs or is anticipated, the torque limit prevents excessive force transmission to the wafer and protection ring, cushioning the impact before it causes damage. This resolves the contradiction by adding reliability through beforehand protection while keeping the mechanism relatively simple.
Solution Approach 2:
The patent introduces a torque limit mechanism as an intermediary between the servomotor and the vertical motion mechanism. This intermediary component monitors and controls the torque transmission, preventing direct transmission of harmful collision forces while allowing normal operational torque to pass through. This adds reliability without requiring complex active sensing and control systems.
2Productivity
If the apparatus uses rapid movement for efficient wafer processing, then the productivity is improved, but the harmful factors increase due to collision risks during fast positioning
Solution Approach 1:
The torque limit mechanism acts as a beforehand cushioning measure that prevents collision damage while allowing rapid movement for productivity. By setting the torque threshold below collision-damaging levels but above normal operational levels, the system maintains high-speed wafer processing efficiency while protecting against harmful collision impacts.
3Reliability
If the apparatus implements collision protection mechanism, then the reliability is improved, but the device complexity increases due to additional components
Solution Approach 1:
The torque limit mechanism serves as a simple intermediary component that passively limits torque transmission without requiring complex active control. It uses mechanical or electrical torque limiting (such as friction brakes, clutch mechanisms, or current limiting in the servo driver) to prevent collision damage while maintaining simplicity and avoiding complex sensing and control systems.
Solution Approach 2:
The torque limit mechanism provides self-service collision protection by automatically limiting torque when thresholds are exceeded, without requiring external monitoring or complex control logic. The mechanism inherently protects the system through its design, reducing reliability improvement while minimizing added complexity.
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
The apparatus effectively prevents adverse consequences of collisions, enhancing the safety and reliability of photolithography tools and minimizing wafer damage by automatically decoupling the servomotor from the vertical motion mechanism during overload conditions.
Implementation Method 1
a compressible spring disposed circumferentially over the transmission sliding pin, the compressible spring is fixed to a spring retainer at one end and abutting against the end portion of the transmission sliding pin on the other end
Implementation Method 2
an electrical control module including a servomotor for generating a rotational motion
Data Source
AI summary
A wafer edge protection apparatus, including an electrical control module having a servomotor, a vertical motion mechanism and a protection mechanism. The protection mechanism includes: a shaft coupler, in fixed connection with a shaft of the servomotor and having a plurality of first connecting components; and a transmission sleeve, in fixed connection with the vertical motion mechanism and having a plurality of second connecting components in movable connection with the plurality of first connecting components. The plurality of first connecting components is in movable connection with the plurality of second connecting components such that, in the event of a torque output by the shaft of the servomotor not exceeding a limit, the plurality of first connecting components is engaged with the plurality of second connecting components, and in the event of the torque output by the shaft of the servomotor exceeding the limit, the plurality of first connecting components is disengaged from the plurality of second connecting components, thereby preventing a rotational motion generated by the servomotor from transferring to the vertical motion mechanism.