C-22values describe: C-22
Semiconductor equipment & lithographyChipmakers (foundries & IDMs)
Why it wins
Where electropolished 316L still corrodes: the nastiest halogen gas lines and abatement-adjacent hardware.
Why not the alternative
316L EP handles most dry lines; wet HBr and HCl chemistry pits it.
Watch out
Cost and machining; specify only the lines that need it.
Properties
The values below are candidate: compiled from the sources named, not yet individually validated.
Provisional provenance: ASM Handbook: properties, corrosion, heat treatment; Semiconductor chamber materials and plasma-resistant coating literature.
Wet cleaning
| Recipe | electropolish to the SEMI gas-system finish, ultrapure DI rinse, dry N₂ |
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| Forbidden | anything leaving a residue in a gas line |
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| Limit | the Ra target of the gas standard, not visual cleanliness |
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Vacuum and outgassing
| Outgassing, unbaked (10 h) | 2e-9 mbar·L/s/cm² |
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| Outgassing, baked | 1e-11 mbar·L/s/cm² |
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| Vapour pressure | negligible |
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Temperature
| Bake, assembled | 450 °C |
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| Vacuum degas | 1000 °C |
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| Braze / H2 firing | 1120 °C |
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| Metallurgical limit | solution anneal 1120 °C |
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Thermal
| CTE | 12.4 ppm/K |
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| Thermal conductivity | 10.1 W/m·K |
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| Specific heat | 414 J/kg·K |
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| Emissivity | 0.2–0.3 |
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| Melting / softening | 1325–1370 °C |
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Mechanical
| Strength | 310 ys MPa |
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| Tensile | 690 MPa |
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| Elongation | 45 % |
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| Young's modulus | 206 GPa |
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| Hardness | ~200 HV |
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| Density | 8.69 g/cm3 |
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Electrical and magnetic
| Relative permeability | ~1.0 |
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| Resistivity | 114 µΩ·cm |
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Engineering
| Corrosion | outstanding: halogens, wet acids, oxidising and reducing |
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| Joining | weldable, matching filler |
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| Process notes | work-hardens fast |
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| Availability and cost | to order, expensive |
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Grades
| C-22 (N06022) | broadest halogen resistance, the semiconductor pick |
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| C-276 (N10276) | the classic wet chlorine alloy |
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Sources · 2
- SEMI F20 and gas system practice
- Haynes International alloy data
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