Inert Gas Purge Particle Sampling for Critical Surface Validation
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Solution Overview
Problem
Existing methods for validating the cleanliness of critical chamber parts in semiconductor wafer fabrication equipment are indirect, unable to detect localized cleanliness variations, and introduce background contamination noise, making them inefficient and inaccurate.
Innovation Solution
A particle measurement system using an inert gas purge method that flows inert gas past critical surfaces of a part, dislodging particles into a mobile phase that can be sampled downstream with on-board analyzers, allowing for direct and precise measurement of surface cleanliness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If indirect methods are used to validate cleanliness of critical chamber parts, then the measurement can be performed without direct contact, but the measurement precision is insufficient and background contamination noise is introduced
Solution Approach 1:
The invention extracts particles from the critical surface by flowing inert gas past the surface, dislodging particles into the gas stream. This separates the measurement process from direct contact with the surface, eliminating background contamination noise while enabling direct particle detection with high precision analyzers
Solution Approach 2:
Inert gas serves as an intermediary medium between the critical surface and the particle analyzer. The gas flows past the surface, picks up dislodged particles, and transports them to the analyzer without introducing contamination, solving both the precision and contamination noise problems
2Loss of information
If indirect validation methods are used, then the process can be simplified, but the ability to detect localized cleanliness variations is lost
Solution Approach 1:
The critical surface is divided into multiple zones with separate gas flow paths, allowing independent sampling and analysis of different regions. This enables detection of localized cleanliness variations while maintaining a relatively simple overall system architecture
Solution Approach 2:
The inert gas flow continuously passes over the critical surface, constantly dislodging and transporting particles to the analyzer. This continuous action provides real-time information about localized cleanliness variations without requiring complex intermittent measurement systems
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 non-destructive, in-line measurement of particle cleanliness on critical surfaces, reducing background noise and allowing for high-precision validation of surface cleanliness before final packaging.
Implementation Method 1
An inert gas is flowed through the test vessel, wherein the test vessel flows the inert gas past one or more critical surfaces of the part
Implementation Method 2
flows inert gas past critical surfaces of a part, dislodging particles into a mobile phase
Implementation Method 3
The inert gas is flowed from the at least one diffuser to a particle counter. The contaminants are measured in inert gas using the particle counter
Data Source
AI summary
An apparatus for measuring contamination on a critical surface of a part is provided. A vessel for mounting the part is provided. An inert gas source is in fluid connection with the vessel and adapted to provide an inert gas to the vessel. At least one diffuser receives the inert gas from the vessel, wherein the critical surface of the part is exposed to the inert gas when the part is mounted in the vessel. At least one analyzer is adapted to receive inert gas from the at least one diffuser and measures contaminants in the inert gas.