Mini Environment for Vacuum Chamber Leak Detection
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Solution Overview
Problem
Current in-situ leak detection methods for vacuum chambers in semiconductor processing, such as RGA and plasma OES, are either too expensive, bulky, or have limited sensitivity and are prone to interference, making early detection of leaks in vacuum systems economically unviable.
Innovation Solution
A mini environment is created within a sensor manifold using a foreline and an assistant gas supply line to flow a testing sample and assistant gas, allowing a sensor, like an SPOES sensor, to detect leaks in vacuum process chambers effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RGA equipment is used for leak detection, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the sensing function from the complex RGA system by using a simplified sensor that detects only specific indicator gases (water vapor, hydrocarbons) relevant to leak detection, eliminating the need for full mass spectrometry equipment while maintaining detection sensitivity for critical parameters
Solution Approach 2:
The patent employs lower-cost sensors with limited operational lifetimes in the foreline environment, accepting that these sensors may degrade or fail but can be replaced economically, thereby avoiding the need for expensive, complex equipment that must maintain long-term reliability
2Device complexity
If oxygen sensors are used for leak detection, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent introduces assistant gas as an intermediary substance that reacts with leaked process gases to produce detectable indicator gases, enabling simple oxygen sensors to indirectly detect leaks with enhanced sensitivity through the mediating chemical reactions in the foreline
Solution Approach 2:
The patent replaces direct physical detection methods with chemical reaction-based detection, where assistant gases chemically transform leaked process gases into detectable products, allowing simple sensors to achieve high measurement precision through chemical mediation rather than direct mechanical or physical measurement
3Device complexity
If SPOES sensors are used for leak detection, then device complexity is reduced, but measurement precision varies and interference increases
Solution Approach 1:
The patent creates a specialized local environment in the foreline with controlled assistant gas composition and pressure conditions optimized for consistent SPOES sensor performance, ensuring uniform detection characteristics regardless of variations in the main chamber environment or different process gases being used
4Measurement precision
If sensors are exposed to reactive process gases, then leak detection capability is improved, but duration of action decreases
Solution Approach 1:
The patent divides the vacuum system into separate functional zones: the process chamber containing reactive process gases is segmented from the foreline containing assistant gases, with the sensor located in the foreline zone, allowing the sensor to detect leaks without direct exposure to damaging reactive gases while maintaining detection capability through the assistant gas mediation mechanism
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 method enables efficient and sensitive leak detection in vacuum chambers, reducing equipment costs and interference, and extends the operational lifetime of sensors by isolating them from reactive gases during testing.
Implementation Method 1
Plasma assisted optical emission spectroscopy (SPOES) is suitable due to its low cost, small size, and long term stability.
Data Source
AI summary
Systems and methods for in-situ leak detection and endpoint detection of wafer dry etch or chamber clean in chambers, e.g., vacuum chambers used in semiconductor processing. A mini environment is created and a sensor, such as an SPOES sensor, can be used in the mini-environment to perform leak detection.