Ultra-High Purity Stainless Steel Coil Tubing — SEMI F19 Specification
Product Overview
Wenzhou Jixing Metal Materials Co., Ltd. (Wenzhou Jixing) manufactures ultra-high purity stainless steel coil tubing (Coiltube) engineered in strict compliance with the SEMI F19 specification — the internationally recognized industry standard governing ultra-high purity (UHP) stainless steel tubing for semiconductor manufacturing environments. This product line addresses the most demanding purity, surface integrity, and contamination control requirements encountered in front-end wafer fabrication, chemical mechanical polishing (CMP), and ultra-clean gas delivery systems.
SEMI F19, established under the Semiconductor Equipment and Materials International (SEMI) standards body, defines performance criteria for stainless steel tubing intended for use in applications where particulate, ionic, and organic contamination must be controlled to sub-nanometer and parts-per-trillion (ppt) levels. Wenzhou Jixing's Coiltube products are designed to meet or exceed every threshold specified in this standard across the full manufacturing chain — from raw material procurement through final packaging and delivery.
Material & Properties
The core material utilized is ASTM A269 / ASME SA-269 Type 304L and 316L ultra-low-carbon austenitic stainless steel, selected for its superior corrosion resistance, mechanical ductility, and resistance to intergranular corrosion in semiconductor-grade chemical environments.
- Material Purity: Carbon content ≤ 0.030% (L-grade); total impurity content (S, P, N, Cr₂O₃ inclusions) controlled to meet SEMI F19 sub-ppm thresholds. Oxygen and nitrogen levels are minimized during vacuum arc remelting (VAR) or electro-slag remelting (ESR) of the starting billets.
- EP (Electro-Polished) Surface Finish: The interior bore receives a proprietary electro-polishing treatment achieving surface roughness Ra ≤ 0.1 μm (100 nanometers), with a passivated chromium oxide layer providing chemical inertness against HF, H₂SO₄, HNO₃, and other semiconductor-grade reagents.
- Mechanical Properties: Tensile strength ≥ 485 MPa (Type 304L) / ≥ 515 MPa (Type 316L); elongation ≥ 40%; fully annealed (Solution Annealed) condition per ASTM A269.
- Corrosion Resistance: Passivated surface resistant to pitting and crevice corrosion in dilute halide environments; resistant to stress corrosion cracking (SCC) at temperatures below 60°C in chloride solutions.
Specifications
| Parameter | Specification | Test Method / Standard |
|---|---|---|
| Material Grade | ASTM A269 / SA-269 Type 304L, 316L | ASTM A269, SEMI F19 |
| Outer Diameter (OD) | 3.175 mm – 50.8 mm (1/8" – 2") | ASTM A269, ±0.05 mm tolerance |
| Wall Thickness | 0.25 mm – 3.00 mm | ASTM A269, ±0.025 mm tolerance |
| Inner Diameter (ID) | 2.50 mm – 47.80 mm | Derived from OD and wall thickness |
| Coil Length | Custom — typically 5 m to 100 m per coil | Customer specification |
| Surface Roughness (ID) | Ra ≤ 0.1 μm (Electro-Polished) | SEMI F19, SEMI F125 |
| Surface Roughness (OD) | Ra ≤ 0.25 μm (Acid Pickled & Passivated) | ASTM A380 |
| Carbon Content | ≤ 0.030% | ASTM A269 |
| Chromium (Cr) | 18.0% – 20.0% (304L) / 16.0% – 18.0% (316L) | ASTM A269 |
| Nickel (Ni) | 8.0% – 10.5% (304L) / 10.0% – 14.0% (316L) | ASTM A269 |
| Molybdenum (Mo) | — (304L) / 2.0% – 3.0% (316L) | ASTM A269 |
| Hardness | ≤ 220 HV (annealed condition) | ASTM E92 |
| Pressure Rating | Up to 1.6 MPa (per wall thickness) | ASTM A312, customer application |
| Operating Temperature | −196°C to +600°C | ASTM A269 |
| Form | Coil Tubing (Coiltube) — continuous wound coil | SEMI F19 |
Manufacturing Process
Wenzhou Jixing's ultra-high purity Coiltube production follows a rigorously controlled, contamination-prevention process chain aligned with SEMI F19 requirements:
- Raw Material Sourcing: Only certified UHP-grade stainless steel rod or bar stock is procured from qualified suppliers. Incoming materials undergo spectrographic analysis (OES) and chemical assay to verify compliance with ASTM A269 and SEMI F19 purity thresholds. Each heat lot is traceable to its mill certificate.
- Forming & Cold Drawing: Rod stock is pierced, annealed, and cold-drawn through precision tungsten carbide dies to achieve the required OD and wall thickness. Drawing is performed in a Class 10,000 (ISO 14644-1 Class 8) cleanroom environment to minimize particulate introduction.
- Solution Annealing: Tubes are heat-treated at 1040°C – 1120°C followed by rapid air cooling to restore full austenitic ductility and eliminate residual stresses introduced during cold working. This ensures consistent mechanical properties and eliminates sensitization risks.
- Pickling & Passivation: Tubes are subjected to a controlled acid pickling process (HNO₃/HF blend) to remove surface oxides, decarburized layers, and mill scale. Subsequent passivation with dilute nitric acid regenerates the protective chromium oxide film, enhancing corrosion resistance per ASTM A380.
- Electro-Polishing (EP): The interior bore undergoes a proprietary electro-polishing process in a heated phosphoric acid bath. This removes the micro-scale roughness peaks and impurity-rich surface layer, producing a mirror-smooth, chemically inert interior surface with Ra ≤ 0.1 μm. The EP process also removes surface-embedded contaminants to depths of 1–3 μm.
- UHP Cleaning: Post-EP tubes are cleaned using semiconductor-grade ultrapure water (resistivity ≥ 18.2 MΩ·cm) and high-purity solvents. Cleaning is performed in a Class 100 (ISO 14644-1 Class 5) cleanroom to prevent re-contamination.
- Coiling: Cleaned tubes are wound onto precision-machined stainless steel coils using a controlled-tension coiling system to prevent kinking, surface damage, or work-hardening. Each coil is inspected for uniformity of winding pitch and absence of mechanical defects.
- Final Inspection & Testing: Each coil undergoes dimensional verification (OD, wall thickness), visual inspection (10× magnification for surface defects), hydrostatic pressure testing, and, where specified, SEMI F19 particle count analysis of the internal bore surface. Spectrographic re-verification of chemical composition is performed on a sample from each coil.
- Clean Packaging: Tubes are sealed in double-layer polyethylene bags with desiccant, then placed in stainless steel or vapor-barrier shipping containers. Packaging materials are pre-cleaned to ISO Class 5 standards. Each shipment is accompanied by a comprehensive Certificate of Conformance (CoC) and Certificate of Analysis (CoA).
Applications
SEMI F19-compliant Coiltube from Wenzhou Jixing is designed for the most contamination-sensitive applications in the semiconductor and advanced materials industries:
- Front-End Wafer Fabrication: Chemical delivery lines (HF, H₂SO₄, HNO₃, HCl, BHF, SPM) in photolithography, etching, and cleaning stations where sub-ppb ionic contamination is unacceptable.
- Ultra-Pure Gas Distribution: Piping for high-purity process gases (N₂, Ar, He, H₂, NF₃, WF₆) in gas panel systems and manifold delivery networks.
- CMP (Chemical Mechanical Polishing) Systems: Slurry delivery and recirculation tubing where particulate control directly impacts wafer surface quality.
- Ultra-Pure Water (UPW) Systems: Distribution tubing for 18.2 MΩ·cm water systems in semiconductor manufacturing facilities.
- Photolithography Systems: Resist and solvent delivery lines requiring ultra-low particle and ionic contamination levels.
- Solar Cell & Flat Panel Display Manufacturing: High-purity chemical and gas delivery in photovoltaic and TFT-LCD fabrication.
- MEMS and Advanced Packaging: Precision chemical delivery in micro-electromechanical systems and advanced packaging processes.
Quality Certifications & Compliance
Wenzhou Jixing's SEMI F19 Coiltube product line is backed by a comprehensive quality management framework ensuring traceability, consistency, and regulatory compliance:
- SEMI F19 Compliance: Full adherence to the SEMI F19 specification for ultra-high purity stainless steel tubing, including material purity, surface finish, and cleanliness requirements.
- ASTM A269 / ASME SA-269: Material and product specification compliance for seamless wrought austenitic stainless steel tubing.
- ASTM A380: Passivation of stainless steel parts and assemblies per recognized industry practice.
- ISO 9001:2015: Quality Management System certification covering design, manufacturing, and delivery processes.
- ISO 14644-1: Cleanroom classification and environmental monitoring for production and packaging areas (ISO Class 5 / Class 8).
- SEMI S2 / SEMI S8: Human and facility electrostatic discharge (ESD) control compliance for semiconductor-grade product handling.
- Full Traceability: Every coil is serialized with a unique lot identifier traceable to the original mill heat, chemical analysis, and all processing parameters — enabling complete backward and forward traceability throughout the supply chain.
Unique Selling Points
- End-to-End Purity Control: Unlike conventional stainless steel tubing suppliers, Wenzhou Jixing implements contamination control protocols across the entire value chain — from raw material selection through manufacturing, inspection, packaging, and shipping. This full-process approach ensures that purity achieved during manufacturing is preserved until the product reaches the customer's facility.
- SEMI F19 Full-Spectrum Compliance: The product is not merely "compatible" with SEMI F19 — it is manufactured to exceed the specification's requirements for material purity, electro-polished surface quality, and clean packaging, providing customers with a margin of safety beyond minimum compliance.
- Proprietary EP Process: Wenzhou Jixing's electro-polishing process is optimized specifically for semiconductor-grade tubing, achieving consistently Ra ≤ 0.1 μm interior surfaces with superior chemical inertness compared to conventional mechanical polishing methods.
- Custom Coil Configuration: Flexible coil lengths, OD, and wall thickness options allow customers to minimize fabrication waste and optimize installation for their specific system architecture — reducing total cost of ownership.
- Comprehensive Documentation: Each shipment includes a Certificate of Conformance, Certificate of Analysis (with full chemical composition and purity data), and process traceability documentation — meeting the rigorous incoming inspection requirements of semiconductor equipment manufacturers (OEMs) and system integrators.
Wenzhou Jixing Metal Materials Co., Ltd. — Delivering ultra-high purity stainless steel solutions engineered to the exacting standards of the semiconductor industry. Where contamination is measured in parts per trillion, our Coiltube performs without compromise.