Substrate Position Sensing via Shaft Load Detection in Closed Chambers
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Solution Overview
Problem
Existing methods for determining the position of a substrate within a closed chamber, such as vacuum chambers used in manufacturing processes, face challenges due to limited precision, sensor reliability issues due to harsh environments, and inability to detect substrate damage accurately.
Innovation Solution
A method utilizing load-converting elements, like piezoelectric or strain gauges, adjacent to rotating shafts within the chamber to measure changes in load and detect substrate presence, allowing for precise position determination and damage detection through changes in output signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical or thermal sensors are installed within the chamber to detect substrate position, then measurement capability is improved, but device complexity and reliability deteriorate due to harsh environmental conditions
Solution Approach 1:
The patent introduces an intermediary mechanism (load-converting element on the transport system) that indirectly detects substrate presence and position without requiring sensors to be directly exposed to harsh chamber conditions. The load-converting element converts mechanical load changes into electrical signals, serving as a mediator between the substrate and the detection system.
Solution Approach 2:
The patent replaces optical or thermal sensing mechanisms with a mechanical load detection system. Instead of using light or heat to detect substrate position, the system uses load-converting elements to detect changes in mechanical load on the transport system, which correspond to substrate presence and position.
2Reliability
If sensors are installed outside the chamber to avoid harsh conditions, then sensor reliability is improved, but measurement precision deteriorates due to limited spatial resolution
Solution Approach 1:
The load-converting element acts as an intermediary positioned at the boundary between the external detection system and the internal substrate. It translates internal mechanical conditions (substrate load on shafts) into external detectable signals, enabling high-precision measurement without exposing sensors to harsh conditions.
3Device complexity
If extrapolation methods are used to determine substrate position from transport system movement, then device complexity is reduced, but measurement precision deteriorates and cannot detect substrate disturbances
Solution Approach 1:
The transport system itself serves the dual function of transporting the substrate and detecting its presence and position. The load-converting elements on the transport shafts automatically detect substrate-related load changes without requiring separate detection systems, enabling the transport system to monitor its own operational status.
4Reliability
If a hermetically closed chamber is used for vacuum processes, then process quality is improved, but measurement capability deteriorates due to inability to install sensors within the chamber
Solution Approach 1:
The load-converting element serves as an intermediary that bridges the hermetically sealed chamber and the external detection system. It is positioned within the chamber but converts mechanical information into electrical signals that can be transmitted externally, maintaining chamber integrity while enabling precise measurement.
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 approach provides high accuracy in substrate positioning and damage detection within closed chambers, even under conditions where optical or thermal sensors are ineffective, ensuring reliable process control and layer thickness monitoring.
Implementation Method 1
providing a load-converting element, in particular a piezoelectric element, which is suited for detecting a load acting on the at least one rotating shaft
Implementation Method 2
load-converting elements, like piezoelectric or strain gauges
Data Source
AI summary
The present invention relates to a method and an apparatus for determining the position of a substrate within a closed chamber, wherein the substrate is moved within the chamber by a transport system comprising at least one rotating shaft. A load-converting element is provided adjacent to at least one of the rotating shafts, wherein the load-converting element detects a load acting on the at least one rotating shaft and converts it into an electrical parameter. While no substrate is present on the at least one rotating shaft, a first output signal corresponding to a first value of the electrical parameter is measured. The output signal is then monitored and a presence of the substrate on the at least one rotating shaft is detected when the output signal differs from the first output signal by at least a predetermined amount.