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Designing a Vacuum Coating System: What You Need to Know
NORTH AMERICA | 18 June 2025 | 6 min
"Small things make perfection, but perfection is no small thing." — Henry Royce.
Nowhere is this quote more true than in the world of thin-film coatings. From the smartphone in your pocket to the optics in space telescopes, these invisible layers quietly enhance performance, durability, and appearance at the microscopic level. But achieving such perfection requires more than just advanced materials, it requires a carefully engineered vacuum environment where every variable is controlled and every component plays its part.
Whether you’re building a new system or refining an existing one, designing a vacuum coating system is an exercise in precision engineering. Here’s what you need to know.
Understanding the Coating Processes
Your first design decision is selecting the right coating process for your application. Each method places unique demands on your system design:
- Physical Vapor Deposition (PVD): Material is vaporized in a vacuum and deposited as a thin film. Clean and versatile, PVD is ideal for optical, decorative, or hard coatings.
- Chemical Vapor Deposition (CVD): Uses chemical reactions in the gas phase to form coatings. It excels at conformal coatings on complex shapes but requires higher temperatures and stringent gas handling.
- Evaporation: A subset of PVD where material is heated (thermally or via e-beam) until it vaporizes. A go-to choice for high-purity, low-temperature coatings.
- Sputtering: Another PVD variant where plasma ejects atoms from a target that then deposit on the substrate. Sputtering delivers excellent adhesion and control, particularly for multilayer and reactive coatings.
Each process has specific vacuum and process control requirements. Understanding them early will help you design a system that performs reliably and efficiently.
Key Components of a Vacuum Coating System
A successful coating system involves more than choosing a deposition source. Thoughtful design across several components is essential:
- Vacuum Chamber: The heart of your system. It must accommodate substrate size, source geometry, and heat load. Stainless steel remains the gold standard for cleanliness and durability.
- Pumping System: Achieving and maintaining proper vacuum levels is critical for coating quality. We offer a wide range of pumping technologies to match your process needs.
- For primary pumps we provide dry scroll pumps, such as our nXDS and XDS series, ideal for smaller PVD systems. For larger PVD systems, dry screw booster combinations like our GXS and EXS paired with EH series booster pumps deliver the high throughput and performance required. In CVD applications, our iXL and iXH dry pumps provide robust, oil-free performance under demanding process conditions.
- Secondary pumps to complement our roughing pumps, our magnetically levitated turbopumps, including the latest nEXT Maglev series, offer vibration-free operation and deliver exceptional base pressures, helping to preserve film purity. For processes that require even lower pressures or must manage high gas loads, such as sputtering or space simulation - our ECP cryopumps and E2CH cold heads provide deep vacuum capabilities: silent, oil-free, and capable of reaching pressures down to 10⁻⁷ Torr and below.
- Delivery & Flow Control: Essential for CVD and reactive sputtering. Precise mass flow controllers and throttle valves ensure stable partial pressures for consistent results.
- Temperature Control: Uniform deposition often depends on stable temperatures. Substrate heaters, cooling jackets, and chillers help maintain critical thermal profiles.
- Instrumentation & Control: Integrated gauges, deposition rate monitors, and process controllers give you the intelligence and automation required to optimize your coatings.
Planning for Performance
Before you begin assembling components, it’s important to think through how your system will perform day-to-day. Here are a few practical considerations:
- Pumpdown Speed vs. Base Pressure: Will your process benefit more from faster cycle times or ultra-clean base pressures? Hybrid pumping stacks, combining maglev turbopumps with cryogenic vacuum technology, can help you achieve both.
- Maintenance Access: Don’t overlook serviceability. Design your chamber and mounting configurations for easy access to sources, feedthroughs, and internal surfaces.
- Contamination Control: Outgassing and hydrocarbon contamination can ruin coatings. Dry pumps and oil-free high vacuum technologies significantly reduce this risk.
- Scalability: Choose components and layouts that allow your system to grow, whether that means adding pump ports, expanding gas lines, or accommodating larger substrates.
What Information Do You Need to Provide?
If you’re just starting the system design process, it helps to think through a few key questions:
- What process are you running—PVD, CVD, sputtering, evaporation?
- What base pressure and pumpdown time are required?
- What gases are involved, and at what flow rates?
- Are there temperature control requirements—heating, cooling, or both?
- What level of automation or process control do you need?
- What space, power, and mobility constraints exist in your facility?
At Edwards, we use a detailed system questionnaire to help customers scope their needs and ensure their vacuum solution is built to perform. To view our questionnaire, CLICK HERE
Designing for Flexibility
Vacuum coating continues to evolve rapidly. Whether you're developing new optical stacks, scaling up thin-film batteries, or experimenting with unique materials, a well-designed system will give you room to innovate.
Our experience shows that investing in stability, cleanliness, and efficiency pays dividends across a system’s life. Whether through next-generation nEXT Maglev turbopumps, advanced cryogenic technology, or fully integrated control platforms, today’s technologies can help you build a system that delivers superior coatings and future flexibility.
Need Help Designing Your System?
If you’re planning a new vacuum coating system, or upgrading an existing one, we’re here to help. Whether you need a turnkey system, an optimized pump package, or simply individual pumps and instruments to integrate into your own build, our team can guide you toward the right solution.
From the first consultation through system design, installation, and ongoing support, we help customers worldwide turn vacuum technology into exceptional coating performance.