On-Tool Mass Flow Controller Diagnostics via Voltage Curve Analysis
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Solution Overview
Problem
Mass flow controllers in manufacturing processes, such as thin film deposition, face issues with precise control and diagnosis, leading to high maintenance costs and downtime due to unforeseen operating inaccuracies or failures, as users often lack the tools and training to diagnose issues promptly.
Innovation Solution
A mass flow controller with a sensing element circuit and differential voltage processing components that allow for on-tool diagnostics, enabling the detection of potential problems by comparing operational voltage pairs to stored reference data, thus identifying deviations and determining if the sensing element circuit has changed since the data was stored.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mass flow controller diagnostic tests are performed by removing the controller from the tool and running tests at a separate test location, then diagnostic accuracy can be improved, but tool downtime and operational costs increase significantly
Solution Approach 1:
The patent introduces an intermediary diagnostic system that interfaces between the mass flow controller and the process control system. This intermediary system enables diagnostics to be performed in-situ without removing the controller from the tool, thereby maintaining tool operational status while achieving accurate diagnostic measurements through the bridging diagnostic interface
Solution Approach 2:
The patent replaces the mechanical approach of physically removing and transporting the mass flow controller to a separate test location with an electronic/digital diagnostic system that performs tests in-situ through software-based monitoring and analysis of controller parameters, eliminating the need for physical relocation
2Reliability
If users replace mass flow controllers when issues arise, then operational reliability is maintained, but maintenance costs increase due to unnecessary replacements
Solution Approach 1:
The patent implements preliminary diagnostic testing that detects potential issues with the mass flow controller before they lead to operational failures. By performing proactive diagnostics and addressing problems early, the system maintains operational reliability while avoiding unnecessary controller replacements and associated costs
Solution Approach 2:
The patent establishes a feedback mechanism where diagnostic information about mass flow controller status is continuously monitored and fed back to users. This feedback enables informed decisions about whether replacement is actually necessary, preventing premature or unnecessary replacements while ensuring timely intervention when genuine problems exist
3Difficulty of detecting and measuring
If comprehensive diagnostic testing is implemented, then issue detection capability is improved, but system complexity and diagnostic time increase
Solution Approach 1:
The patent divides the diagnostic system into segmented, modular components that can independently assess different aspects of mass flow controller performance. This segmentation allows comprehensive diagnostics to be performed through multiple simple, focused tests rather than one complex monolithic system, reducing overall system complexity while maintaining high issue detection capability
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 solution allows for the assessment of mass flow controllers while they are still coupled to the tool, reducing downtime and maintenance costs by enabling users to address issues before they become major problems, ensuring accurate flow rate control and extending the lifespan of the equipment.
Implementation Method 1
a sensing element circuit coupled to the control component, the sensing element circuit including a bridge circuit including a first, second, third, and fourth nodes, a first resistive component being connected between the first and second nodes
Data Source
AI summary
Mass flow controllers with on-tool diagnostic capabilities and methods for on-tool diagnostics are disclosed. A mass flow controller includes a differential voltage processing component to provide a first output that is indicative of a differential voltage between second and fourth nodes of a bridge circuit and a top voltage processing component provides a second output indicative of a top voltage between the first node and the third node of the bridge circuit. Top-and-differential voltage reference data stored in non-volatile memory defines a characteristic curve relating top voltage reference values to corresponding differential voltage reference values. A sensor analysis component obtains a top and differential voltage pair and assesses whether the top and differential voltage pair deviates from the characteristic curve to determine whether the sensing element circuit has changed since the top-and-differential voltage reference data was stored in the non-volatile memory.