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The Focus Ring 305-80-T5.5 297 (Tokyo Electron OEM P/N 2L10-252427-11) is a precision annular consumable that sits at the outer perimeter of the electrostatic chuck in a TEL 300 mm plasma etch chamber. It encircles the 300 mm wafer, bridging the discontinuity between the wafer edge and the surrounding chamber hardware so that the plasma sheath, electric field and reactive ion flux behave as uniformly over the wafer edge as they do across its centre. The cryptic descriptor in the part name, a 305 mm class outer geometry, an 80 series profile, a nominal 5.5 mm thickness reference and a 297 dimensional callout, describes the ring’s stepped cross-section and bore, all of which are tuned to a specific etch recipe envelope and electrode stack.
Often called an edge ring or focus ring, this component is one of the most influential consumables in the chamber. Although it carries no moving parts and no active electronics, its dielectric properties, dimensional accuracy and erosion behaviour directly shape the edge exclusion zone, the bevel of the plasma sheath and the trajectory of incoming ions in the outermost few millimetres of every wafer processed.
Because the focus ring is sacrificial and erodes with accumulated RF hours, it is replaced on a defined preventive maintenance cadence. A dimensionally faithful, material-matched replacement such as ES7099-175 is therefore central to maintaining stable edge yield, predictable chamber matching and consistent particle performance over the life of the tool.
In a TEL 300 mm etch chamber the focus ring extends the effective electrical and physical plane of the wafer outward, so that the wafer edge does not behave as an abrupt boundary that distorts the plasma. Its core functions include:
Focus rings for TEL etch chambers are produced from process-grade materials selected to match the chemistry they face, commonly high-purity silicon, silicon carbide or quartz for conductor and dielectric etch, with the exact grade chosen to control erosion rate, particle generation and electrical behaviour. Material purity is critical: trace metallic contamination at the wafer edge can degrade device yield, so the ring is manufactured to semiconductor-grade specifications.
The stepped profile, bore diameter, flatness and thickness encoded in the 305-80-T5.5 297 designation define how the ring seats against the chuck and how it positions the wafer edge relative to the sheath. Even small deviations in thickness or step height shift the sheath shape and alter edge etch results.
Because the focus ring governs the outermost few millimetres of every wafer, its condition has an outsized effect on edge yield and overall chamber stability. As the ring erodes, the consequences accumulate:
The dominant wear mode is steady erosion of the upper surface and inner step under ion bombardment. As the ring thins, the sheath drops relative to the wafer edge and edge etch results drift out of specification, which is why thickness is the primary end-of-life criterion.
Silicon and quartz rings are brittle. Thermal cycling, mishandling during installation or localised hot spots can initiate cracks or chips, especially near the thin inner step. A fractured ring sheds particles and can compromise wafer seating, so any visible damage warrants immediate replacement.
Etch by-products deposit on the ring as polymer films. When these layers thicken and flake they become a particle source, and embedded contaminants can transfer to the wafer edge. Build-up also changes the ring’s effective surface and local electrical behaviour between cleans.
Focus ring replacement is a routine preventive maintenance task, but it must be carried out cleanly and precisely to protect both the chuck and edge yield. A typical sequence is as follows:
Focus rings are scheduled consumables, so keeping a qualified, reliable supply on the shelf avoids unplanned downtime and yield excursions. ESCT Fab Support offers ES7099-175 as a cost-effective second-source alternative with the following advantages:
It surrounds the 300 mm wafer at the edge of the electrostatic chuck and extends the plasma sheath and electric field beyond the wafer, keeping edge etch rate, profile and ion angle uniform and protecting the chuck from direct plasma attack.
No. ES7099-175 is supplied as a new, second-source OEM-compatible focus ring. It is verified to the form, fit and function of TEL OEM P/N 2L10-252427-11 but is not an original Tokyo Electron branded part.
Replacement is driven by accumulated RF hours or wafer count and by erosion measured against the end-of-life thickness limit. The exact interval depends on your recipe aggressiveness and chemistry, so it is set by each fab’s preventive maintenance plan.
Common indicators are edge etch rate or critical-dimension drift, increasing edge tilt, rising particle counts at the wafer edge, and measured thickness below the end-of-life limit. Visible cracking, chipping or heavy polymer build-up also warrant replacement.
A new ring restores the intended edge geometry, but most fabs run a short season and a qualification or matching wafer after replacement to confirm the chamber is back within its matched window before returning it to production.
ES7099-175 typically carries a lead time of 4-5 weeks. Because focus rings are scheduled consumables, we recommend ordering ahead of planned preventive maintenance windows to maintain buffer stock.
The Focus Ring 305-80-T5.5 297 (TEL OEM P/N 2L10-252427-11, ESCT P/N ES7099-175) is a sacrificial edge consumable that shapes the plasma sheath and electric field around the wafer perimeter in TEL 300 mm plasma etch chambers. Its material purity and precise stepped geometry govern edge etch uniformity, profile control, particle performance and chamber matching, while controlled erosion protects the electrostatic chuck beneath it. Supplied new from a second source and verified to OEM form, fit and function, ES7099-175 offers a cost-effective, reliably available replacement to keep edge yield stable across the consumable’s service life.
Disclaimer: This part is supplied by ESCT Fab Support as a new, OEM-compatible second-source component, verified to the form, fit and function of Tokyo Electron part number 2L10-252427-11. It is not an original OEM part and is not sold as one. It is not manufactured by, endorsed by, or affiliated with Tokyo Electron, and all manufacturer names and part numbers are quoted for identification and compatibility purposes only.
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