Spin Head Chuck Pin Stability via Reverse Centrifugal Force
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Solution Overview
Problem
In semiconductor processes, the centrifugal force during substrate rotation causes chuck pins to move from supporting to waiting positions, leading to unstable substrate support and defects, especially when one chuck pin faces a notch or when the substrate is supported by a small number of pins.
Innovation Solution
A spin head design with a chuck pin moving unit that uses reverse centrifugal force, magnetic force, or elastic members to maintain chuck pins at supporting positions, ensuring stable substrate support even at high speeds and when facing notches, by employing rotation rods with specific geometries and magnetic interactions to manage the movement of chuck pins between supporting and waiting positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chuck pins are placed at supporting positions to support a substrate during rotation, then the substrate can be held in place, but centrifugal force causes the chuck pins to move toward waiting positions, making it difficult to stably support the substrate
Solution Approach 1:
The patent introduces a counterbalancing weight on the rotating arm that offsets the centrifugal force acting on the chuck pin. The weight is positioned such that its centrifugal force counteracts the force moving the chuck pin outward, allowing the spring to maintain the chuck pin in contact with the substrate during rotation.
Solution Approach 2:
The patent changes the physical state of the chuck pin positioning system by introducing a spring mechanism that can dynamically adjust the position of the chuck pin. The spring constant and pre-compression are designed to compensate for centrifugal force effects at different rotation speeds, maintaining stable substrate support.
2Reliability
If three chuck pins are provided to each group and one chuck pin is disposed in a notch of the substrate, then the substrate can be supported, but the substrate is supported substantially by only two chuck pins, making it difficult to stably support the substrate
Solution Approach 1:
The patent introduces an asymmetric cam mechanism that provides different support characteristics for each chuck pin. The cam profile is designed such that when one chuck pin encounters a notch in the substrate, the cam mechanism compensates by providing additional support force through its geometric shape, ensuring all three pins contribute to stable substrate support.
Solution Approach 2:
The patent introduces a cam mechanism as an intermediary between the rotating arm and the chuck pins. This cam mechanism translates the rotational motion into vertical motion that compensates for substrate irregularities such as notches, ensuring continuous and stable support from all three chuck pins.
3Ease of operation
If chuck pins move between waiting positions and supporting positions during a process, then the substrate can be loaded and unloaded, but the space between chuck pins at waiting positions is greater than at supporting positions, causing instability
Solution Approach 1:
The patent introduces a dynamic adjustment mechanism where the relative positions of the chuck pins are continuously adjusted during the loading and unloading process. The mechanism ensures that when pins are at waiting positions for substrate exchange, they maintain optimal spacing, and when transitioning to supporting positions, they automatically converge to provide stable, consistent spacing for substrate support.
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 design ensures stable substrate support during high-speed rotation and when one chuck pin faces a notch, reducing defects by maintaining chuck pins in contact with the substrate, thereby enhancing the reliability of semiconductor processing.
Implementation Method 1
when the body rotates, the rotation rod may use reverse centrifugal force to apply force to the chuck pin from the waiting position to the supporting position
Implementation Method 2
The driving member may include: a driven magnet coupled to the second part of each of the rotation rods; and a driving magnet facing the driven magnets under the driven magnets, wherein the driven magnet and the driving magnet have identical poles facing each other
Data Source
AI summary
Provided is a spin head supporting a substrate and rotating the substrate. The spin head includes a body, chuck pins installed on the body and moving between supporting positions where a substrate is supported and waiting positions providing space for loading/unloading of the substrate, and a chuck pin moving unit configured to move the chuck pins. The chuck pin moving unit includes a rotation rod coupled with each of the chuck pins, a pivot pin fixing the rotation rod to the body, and a driving member rotating the rotation rod about the pivot pin as a rotation shaft to move the chuck pin from the supporting position to the waiting position. When the body rotates, the rotation rod uses reverse centrifugal force to apply force to the chuck pin from the waiting position to the supporting position. The chuck pins include first pins and second pins that alternately chuck a substrate during a process.