Toroidal Magnet Level Sensing for Solid Precursor Vessels
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Solution Overview
Problem
Existing level sensors for solid precursors in semiconductor manufacturing are impractical due to the non-uniform sublimation of solids, leading to inaccurate readings and potential waste of valuable precursors and ruined wafers.
Innovation Solution
A system using toroidal magnets and reed switches within a tube to sense the location of the magnets relative to the switches, allowing precise measurement of solid precursor levels in vessels, eliminating the need for additional ports and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional level sensors are used for solid precursors, then the system structure is simple, but the measurement precision is poor due to non-uniform sublimation
Solution Approach 1:
The patent introduces a toroidal magnet as an intermediary element that rests on the solid precursor surface. This magnet serves as a mediator between the precursor material and the reed switch sensor, allowing indirect measurement of precursor level through the magnet's position changes. The magnet converts the physical state of the precursor (present/absent) into a detectable magnetic field signal, resolving the measurement accuracy problem without requiring direct contact between sensor and precursor.
Solution Approach 2:
The patent replaces traditional mechanical level sensors with a magnetic field-based sensing system. Instead of using mechanical floats or direct contact sensors that physically interact with the solid precursor, the system uses a reed switch to detect the magnetic field generated by the toroidal magnet. This substitution eliminates mechanical contact issues and enables more precise, reliable level detection through magnetic field interactions.
2Loss of substance
If precise level monitoring is implemented, then precursor waste is reduced, but device complexity increases
Solution Approach 1:
The toroidal magnet automatically responds to the precursor level by moving or repositioning itself based on the precursor surface height. The system requires no external actuation or complex control mechanisms - the magnet self-adjusts its position according to the precursor amount, providing automatic level indication. This self-service mechanism reduces precursor waste through accurate monitoring while keeping the device structure simple.
3Productivity
If real-time monitoring is added to prevent wafer ruin, then productivity is protected, but device complexity increases
Solution Approach 1:
The level sensing system operates continuously throughout the precursor delivery process, providing uninterrupted monitoring from the moment the vessel is loaded until the precursor is depleted. The reed switch continuously detects the magnet's position, enabling real-time awareness of precursor levels without interruption. This continuous action allows for timely intervention before precursor exhaustion, preventing wafer ruin and maintaining production continuity.
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 system provides accurate real-time monitoring of precursor levels, reducing waste and production interruptions by ensuring timely refills and maintaining consistent deposition processes.
Implementation Method 1
at least one toroidal magnet, wherein the tube extends through an opening defined by the at least one toroidal magnet, such that the at least one toroidal magnet is slidably engaged with the tube; wherein, when a solid precursor is loaded onto the at least one tray, the at least one toroidal magnet is configured to rest on a surface of the solid precursor
Implementation Method 2
a level sensor comprising: at least one reed switch located on the tube; and at least one toroidal magnet, wherein the tube extends through an opening defined by the at least one toroidal magnet, such that the at least one toroidal magnet is slidably engaged with the tube
Data Source
AI summary
Some embodiments of the present disclosure relate to a system, comprising a vessel; at least one tray located in the vessel; a tube extending into the vessel to a location beneath the at least one tray; and a level sensor comprising: at least one reed switch located on the tube; and at least one toroidal magnet, wherein the tube extends through an opening defined by the at least one toroidal magnet, such that the at least one toroidal magnet is slidably engaged with the tube; wherein, when a solid precursor is loaded onto the at least one tray, the at least one toroidal magnet is configured to rest on a surface of the solid precursor; wherein the level sensor is configured to sense changes in the location of the at least one toroidal magnet relative to the at least one reed switch to sense precursor levels within the vessel. Also described is a vessel for delivering solid precursor vapor where a sensor or heater is connected through a gas exchange port of the vessel.