Ampoule Auto-Refill Control for Stable CVD Precursor Delivery
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Solution Overview
Problem
In semiconductor manufacturing, the refilling of ampoules during chemical vapor deposition processes leads to variations in pressure and temperature, causing process drift and requiring complex and costly heating elements to maintain stability.
Innovation Solution
An auto-refill system with liquid level sensors positioned along the ampoule's height, controlling the operation to activate and deactivate a bulk valve based on liquid levels, ensuring precise refilling and minimizing temperature and pressure fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heating elements are added to the ampoule to maintain temperature stability during refilling, then temperature stability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The system uses the refilling process itself to maintain temperature stability. By controlling the refilling rate and using the incoming liquid's thermal properties, the system self-regulates temperature without requiring external heating elements within the ampoule, thus avoiding increased device complexity
Solution Approach 2:
The invention changes the refilling parameters (flow rate, pressure, timing) to optimize temperature stability during refilling. By adjusting these parameters, the system maintains thermal stability without adding heating elements, resolving the contradiction between temperature control and system simplicity
2Reliability
If heating elements are added to the ampoule to prevent process drift, then process stability is improved, but manufacturing cost increases
Solution Approach 1:
The system achieves process stability through intelligent control of the refilling process itself. The controller monitors parameters and adjusts refilling operations to prevent process drift, eliminating the need for expensive heating elements while maintaining reliability
Solution Approach 2:
The system implements feedback control by monitoring temperature and pressure during refilling and adjusting the refilling rate accordingly. This feedback mechanism prevents process drift without requiring additional heating components, reducing manufacturing costs while maintaining process stability
3Productivity
If manual refilling operations are performed, then system simplicity is maintained, but productivity decreases due to downtime
Solution Approach 1:
The system performs self-refilling automatically without human intervention. The controller detects when the liquid level is low and automatically initiates the refilling process, maintaining high productivity while keeping the overall system design simple and avoiding complex automated robotic handling systems
Solution Approach 2:
The system prepares for refilling in advance by monitoring liquid levels continuously and initiating the refilling process before the ampoule is completely empty. This preliminary action ensures continuous operation and high productivity without requiring complex automated intervention
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 maintains consistent liquid levels and reduces process drift, simplifying the system design and reducing costs by automating the refilling process while maintaining precise control over gas flows.
Implementation Method 1
Each of the plurality of liquid level sensors is positioned at a known location vertically along a height of an inner surface of the ampoule. Each of the liquid level sensors is configured to send a signal to a sensor controller for detecting a liquid level in the ampoule.
Implementation Method 2
The gas delivery controller is prompted to activate the bulk valve when the liquid level is at the low liquid level L, and the gas delivery controller is prompted to deactivate the bulk valve when the liquid level is at the full liquid level state.
Implementation Method 3
Over multiple cycles, the closed container or ampoule has to undergo a refilling process during which the pressure and temperature within the closed container or ampoule can vary. Due to lower temperature of fresh liquid, temperature of the liquid in the ampoule drops and causes process drift
Implementation Method 4
temperature of the liquid in the ampoule drops and causes process drift, which is conventionally controlled by pre-heating the precursor or including heating elements within the closed container or ampoule
Data Source
AI summary
An system, method and software for controlling processes of an auto-refill system of an ampoule including one or more sensors configured to determine one or more liquid level heights within the ampoule. The auto-refill system having a state machine configured to control the auto-refill system, the state machine having one or more states for refilling the ampoule.