15
2026-08
SUS304 vs. SUS316 for Chemically Etched Evaporation Masks
Introduction
SUS304 and SUS316 are both austenitic stainless steels frequently specified for evaporation masks, shadow masks, and other precision-etched deposition components. Their mechanical and forming characteristics are broadly similar, yet they are not interchangeable. Selection must account for the deposition environment, cleaning chemistry, corrosion risk, material thickness, aperture geometry, residual-stress behavior, and intended reuse life.
Inside a controlled vacuum system the dominant performance drivers are often sheet flatness, thickness consistency, aperture accuracy, and thermal expansion rather than bulk corrosion resistance. Nevertheless, when aggressive cleaning cycles or chloride-bearing environments are present, the alloy difference becomes functionally significant.
Key Material Differences
Evaluation Item | SUS304 | SUS316 |
General availability | Broad | Broad, typically higher cost |
Corrosion resistance | Adequate for many controlled environments | Superior resistance in chloride-containing media |
Molybdenum content | Not intentionally added | Typically contains molybdenum |
Chemical etching | Suitable | Suitable; process parameters require grade-specific validation |
Mechanical stability | Good | Good |
Cleaning compatibility | Application-dependent | Often preferred for more aggressive cleaning cycles |
Typical use | General deposition and laboratory masks | Corrosive environments and high-reuse applications |
The intentional molybdenum addition in SUS316 improves resistance to localized attack, particularly pitting and crevice corrosion in chloride-bearing solutions. This advantage does not automatically make SUS316 the superior evaporation-mask material. In a dry, well-controlled vacuum chamber the incremental corrosion benefit may be outweighed by cost, thickness availability, or residual-stress differences arising from the specific mill condition of the sheet.
Do SUS304 and SUS316 Etch Identically?
No. Chemical etching response is governed by alloy composition, sheet temper, grain structure, surface condition, and etchant control. Photochemical machining is a partially isotropic process: material is removed both through the sheet thickness and laterally beneath the photoresist edge. The relationship between etch depth and lateral undercut is commonly expressed by the process-specific etch factor:
where
= etch factor,
= etch depth,
= lateral undercut on one side.
A higher etch factor corresponds to a more nearly vertical sidewall, yet the numerical value is not an intrinsic property of either SUS304 or SUS316. It also depends on spray pressure, etchant concentration and temperature, feature density, resist adhesion, and total etching time.
Consequently, artwork compensation developed for SUS304 cannot be transferred directly to SUS316 without revalidation. Differences in dissolution rate and undercut alter final aperture width, edge profile, and dimensional yield. For micro-openings approaching the practical process limit (approximately 20 µm under favorable conditions of thickness, pitch, and material), these differences become especially pronounced.
NKEYTO evaluates customized stainless-steel thicknesses in the approximate range 0.01–2.0 mm. Common production thicknesses include 0.03 mm, 0.05 mm, 0.10 mm, 0.20 mm, 0.50 mm, and 1.00 mm. Pattern accuracy typically falls in the range ±0.01–0.05 mm, contingent on structure, thickness, and process route. These capability statements remain subject to specific design review; they are not universal guarantees independent of geometry and material condition.
Which Grade Should Be Selected?
SUS304 is often appropriate when:
- The deposition environment is dry and chemically controlled.
- Cleaning chemistries are compatible with standard austenitic stainless steel.
- Material cost and broad availability are primary considerations.
- The mask is intended for prototype work or moderate reuse cycles.
- Chloride exposure is limited or absent.
SUS316 may be preferred when:
- Chloride-bearing cleaning solutions are used.
- The mask must withstand repeated aggressive cleaning cycles.
- Localized corrosion constitutes a measurable contamination risk to the substrate or chamber.
- The operating environment demands higher corrosion resistance.
- Extended reuse life justifies the incremental material cost.
Neither grade, by itself, guarantees dimensional stability. For thin foils the residual stress state and rolling condition of the incoming sheet frequently exert a greater influence on final flatness than the nominal alloy designation. Thickness consistency, surface finish, and grain orientation must therefore be specified and verified.
Engineering Recommendation
Specify the complete material condition rather than the generic term “stainless steel.” The drawing or purchasing specification should identify:
- Exact alloy grade (SUS304 or SUS316)
- Sheet thickness and thickness tolerance
- Surface finish requirement
- Hardness or temper, where relevant
- Any grain or rolling-direction constraints
- Flatness requirement under defined measurement conditions
- Cleaning chemistry and method
- Intended number of reuse cycles
A drawing-based DFM review should then confirm whether the selected alloy, thickness, aperture size, web width, open-area ratio, and tolerance combination can be processed at an acceptable yield rate. Particular attention is required when the thickness-to-opening ratio approaches process limits, when open area is high, or when tight positional registration to substrate features is mandatory.
Request a Material and Process Review
To evaluate the suitability of SUS304 versus SUS316 for a specific evaporation mask, supply the CAD data (DXF, DWG, STEP, IGES, or PDF), required thickness, aperture dimensions and pitch, critical tolerances, overall mask size, cleaning method, expected reuse cycles, and deposition environment. An engineering review can quantify the interaction between alloy choice, etch-factor behavior, structural stability, and production yield before artwork or tooling is released.
About NKEYTO
NKEYTO is the international brand of Shenzhen Xintu Precision Hardware Co., Ltd., a precision metal manufacturing supplier based in Shenzhen, China.
We provide one-stop precision metal manufacturing services, including chemical etching, precision laser cutting, stamping, CNC machining, electroplating, and other customized surface treatments. Our capabilities support the development and production of precision metal components for industries such as semiconductors, electronics, optics, medical devices, and industrial applications.
With engineering support and flexible manufacturing capabilities, we help customers develop customized metal parts from prototypes to small and medium-volume production.
For technical evaluation or quotation, please feel free to contact:
Luna
Head of International Trade & Pre-Sales Technical Consultant
Email: luna@nkeyto.com
WhatsApp: +1 213 221 9094
Phone / WeChat: +86 135 5470 8126
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Shenzhen Nkeyto Precision Hardware Co., Ltd. is a factory specializing in precision hardware processing, committed to providing customers with high-quality products and services.We look forward to working with you.
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E-mail: luna@nkeyto.com
Tel: +1 213-221-9094
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