RGA
What is RGA (Residual Gas Analysis)?
RGA (Residual Gas Analysis) is a vacuum-compatible mass spectrometry technique—most commonly using a quadrupole mass analyzer—to measure the composition of gases in a vacuum system or gas stream. It is widely used to detect and monitor outgassing, leaks, contamination, and process-related gas species by measuring mass-to-charge (m/z) signals across a defined range.
RGA is especially valuable for semiconductor, vacuum processing, materials, and reliability applications where trace gases (e.g., H₂, H₂O, N₂, O₂, CO/CO₂, hydrocarbons, fluorinated species) can affect yield and performance.
What RGA Can Help You Solve
Leak detection support and vacuum integrity troubleshooting (e.g., air leaks, virtual leaks)
Outgassing evaluation of materials and components under vacuum or controlled conditions
Contamination screening (hydrocarbons, pump oil backstreaming indicators, solvent residues)
Process monitoring for vacuum tools (baseline gas composition, abnormal spikes, drift)
Moisture and oxygen control verification (H₂O, O₂ signals)
Comparative analysis (before/after cleaning, bake-out, conditioning, or component replacement)
Typical Applications
Semiconductor & electronics vacuum tools: chamber qualification, troubleshooting, baseline monitoring
Thin film deposition & etch processes: residual gases, byproduct tracking, contamination assessment
Vacuum packaging & reliability: package atmosphere evaluation (project-dependent), moisture/outgassing checks
Materials & components: O-rings, adhesives, coatings, plastics, lubricants, and assembled parts outgassing
R&D vacuum systems: diagnosing background gases during experiments or instrument commissioning
Measurement Capabilities & Outputs
Measurement Options
Mass scan (m/z spectrum): identifies dominant gas species and background profile
Trend monitoring over time: tracks gas evolution during pump-down, bake, or process steps
Targeted monitoring (selected m/z): focuses on critical species (e.g., 18 for H₂O, 28 for N₂/CO, 32 for O₂, 44 for CO₂, hydrocarbon fragments)
What You Receive
RGA spectra (mass scan plots) and/or time-trend plots
Key species interpretation (likely contributors and diagnostic guidance)
Comparisons across conditions or samples (optional)
Notes on common interferences (e.g., overlapping fragments at the same m/z)
Sample / System Requirements
Depending on your project, we can support:
In-situ chamber/system measurement: your vacuum system connected to an RGA port (project-dependent)
Material outgassing tests: samples placed in a controlled vacuum environment to measure evolving gases
General Requirements
Provide sample description, expected materials, and any processing history (cleaning, bake, exposure)
For outgassing: indicate temperature limits, desired test conditions (room temp / elevated temp / bake profile)
Share safety information (SDS) and confirm no restricted hazardous gases unless pre-approved
For best comparisons: provide a control/reference (known-good component or baseline run)
Workflow
Requirement review (leak vs outgassing vs monitoring; target species; acceptance criteria)
Test planning (mass range, scan settings, time duration, temperature/bake steps if applicable)
Measurement execution (baseline → monitoring/trending → condition changes as required)
Data analysis (species assignment, trends, comparison across conditions)
Report delivery (plots + interpretation + recommended next actions)
FAQs
Can RGA confirm an air leak?
RGA can strongly indicate an air leak by observing characteristic signals (commonly N₂/O₂-related peaks and water) and their behavior during pump-down. It is often used together with standard leak-check methods for confirmation.
Can RGA identify the exact gas species?
RGA provides mass-to-charge signals, and some gases share overlapping fragments (e.g., m/z 28 can represent N₂ and/or CO). We use peak patterns and context to interpret results, and we can recommend complementary tests when definitive identification is required.
Is RGA quantitative?
RGA is typically qualitative or semi-quantitative. Absolute concentration reporting requires calibration and stable conditions; feasibility depends on your species and setup.
What does “outgassing” look like in RGA data?
Outgassing often appears as elevated H₂O (m/z 18), CO/CO₂ (m/z 28/44), hydrocarbon fragments, and time-dependent decay or changes during temperature steps.
What’s the difference between RGA and GC/MS?
RGA measures gases directly in vacuum (real-time) and is excellent for troubleshooting and monitoring. GC/MS is typically used for separated gas mixtures and detailed compound identification, often requiring sampling and preparation.
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