A High Purity Alumina Guard Ring is a dense alumina ceramic ring installed inside a vacuum process chamber to shield nearby assemblies (such as chuck surrounds and heater-adjacent parts) from plasma exposure, deposition build-up, and mechanical wear, so the ring can be replaced as a consumable while protecting higher-cost components.
High Purity Alumina Guard Ring Benefits
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Controlled fit geometry (seat-first design):
Step faces, locating shoulders, and datum-defined contact zones are engineered to prevent rocking and “floating” after chamber cleaning, so the guard ring seats the same way every rebuild. -
Edge integrity for maintenance cycles (handling-proof details):
Edge breaks (chamfer/radius), protected corners, and non-critical relief zones are specified to reduce chip initiation during tool contact, lifting, and repeated changeovers—especially on large-diameter rings. -
Repeatable clearance control (gap stays predictable):
Concentricity and functional datums are controlled to keep ring-to-assembly gaps consistent after disassembly/cleaning, helping avoid interference, uneven contact, or misalignment when the chamber is reassembled. -
Deposit-management surfaces (cleaning-friendly interface):
Functional faces can be ground while non-functional surfaces remain as defined, improving cleaning repeatability and reducing “stuck parts” caused by deposit buildup at sharp transitions or uncontrolled surface zones. -
Interchangeable spare strategy (same part fits across cycles):
Profile symmetry, controlled step height, and agreed inspection points support batch-to-batch interchangeability, so maintenance teams can stock the same High Purity Alumina Guard Ring and swap without rework.
High Purity Alumina Ceramic Guard Ring Properties
| Property | Unit | 99.5% Al₂O₃ | 99.6% Al₂O₃ | 99.7% Al₂O₃ | 99.8% Al₂O₃ | 99.9% Al₂O₃ | 99.99% Al₂O₃ |
| Alumina content | % | 99.5 | 99.6 | 99.7 | 99.8 | 99.9 | 99.99 |
| Density | g/cm³ | 3.89 | 3.91 | 3.92 | 3.93 | 3.94 | 3.98 |
| Open porosity | % | 0 | – | – | – | – | – |
| Color | – | Ivory | Ivory | Ivory | Ivory | Ivory | Ivory |
| Water absorption | % | – | 0 | 0 | 0 | 0 | 0 |
| Young’s modulus (Elastic modulus) | GPa | 375 | 356 | 357 | 358 | 359 | 362 |
| Shear modulus | GPa | 152 | – | – | – | – | – |
| Bulk modulus | GPa | 228 | – | – | – | – | – |
| Poisson’s ratio | – | 0.22 | – | – | – | – | – |
| Compressive strength | MPa | 2600 | 2552 | 2554 | 2556 | 2558 | 2570 |
| Flexural strength | MPa | 379 | 312 | 313 | 314 | 315 | 320 |
| Fracture toughness | MPa·m¹ᐟ² | 4 | – | – | – | – | – |
| Hardness | GPa | 14.1 (≈1440 kg/mm²) | 23 | 24 | 25 | 26 | 30 |
| Thermal conductivity | W/m·K | 35 | 32–37 | 33–38 | 34–39 | 35–40 | 36–42 |
| Thermal shock resistance ΔT | °C | – | 222 | 223 | 224 | 225 | 228 |
| Maximum use temperature (no load) | °C | ≤1750 | 1755 | 1760 | 1765 | 1770 | 1800 |
| Coefficient of thermal expansion | 10⁻⁶/°C | 8.4 | – | – | – | – | – |
| Specific heat | J/kg·K | 880 | – | – | – | – | – |
| Volume resistivity | Ω·cm | >1×10¹⁴ | >1×10¹⁴ | >1×10¹⁴ | >1×10¹⁴ | >1×10¹⁴ | >1×10¹⁴ |
| Dielectric constant (relative permittivity) | – | 9.8 | 9.83 | 9.84 | 9.85 | 9.86 | 9.92 |
| Dielectric strength | kV/mm | 16.9 | 23.2 | 23.4 | 23.6 | 23.8 | 24 |
| Dissipation factor (loss factor @ 1 kHz) | – | 0.0002 | – | – | – | – | – |
High Purity Alumina Guard Ring Specifications
| High Purity Alumina Guard Ring | ||
| Item No. | Diameter (mm) | Thickness (mm) |
| AT-HP-BH01 | Customize | |
High Purity Alumina Guard Ring Packaging
- Individual ring protection with foam cavity or layered foam to prevent edge contact
- Double-bag or clean bag option to reduce handling contamination
