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The Focus Ring 360-298.1-T12.1S is a circumferential plasma-confinement consumable installed at the wafer edge inside Tokyo Electron (TEL) 300 mm plasma etch process chambers. Designated by OEM part number 2L10-252706-11 and supplied by ESCT Fab Support under part number ES7099-216, this component sits in the annular pocket surrounding the electrostatic chuck, framing the 300 mm wafer and extending the plasma sheath beyond the silicon edge. The “T12.1S” suffix denotes the ring’s specific thickness and profile revision, a dimension that is critical because focus ring height directly governs the local sheath shape and therefore the ion trajectory at the outermost few millimetres of the wafer.
In a dielectric or conductor etch process, the wafer edge is the hardest region to control. Without a focus ring, the plasma sheath would bend sharply at the chuck periphery, tilting the ion flux inward and skewing etch profiles for the dies nearest the bevel. The focus ring restores a continuous, planar electrical and physical boundary that effectively makes the chamber “see” a larger wafer, pushing the sheath distortion out beyond the productive die area. As a sacrificial part directly exposed to ion bombardment, polymer deposition and fluorine- or chlorine-based chemistries, it is one of the most frequently replaced consumables in the chamber.
Because its geometry and material erode predictably over RF hours, the focus ring is a primary lever in TEL preventive maintenance schedules. Maintaining a qualified supply of ES7099-216 lets fabs hold edge yield steady, shorten wet-clean and parts-swap windows, and avoid the chamber-to-chamber drift that follows an unplanned ring change.
The focus ring performs several overlapping electrical and process functions simultaneously, which is why a comparatively small dimensional change has an outsized effect on edge results:
Focus rings for TEL etch chambers are produced from high-purity etch-grade materials selected for their erosion behaviour under aggressive halogen plasmas, typically silicon, silicon carbide or quartz depending on the process recipe and the chamber generation. The material must erode slowly and, crucially, uniformly, so that the ring’s exposed profile recedes in a predictable manner rather than pitting locally.
The “T12.1S” thickness designation underlines how tightly the ring height, flatness and inner-diameter gap must be held. Sheath height above the ring scales with ring height, so any deviation from the qualified profile shifts edge ion angle and etch rate. Equally, the ring’s dielectric constant and resistivity influence the local RF coupling.
Because the focus ring controls the most error-prone region of the wafer, its condition feeds directly into edge die yield and into how often a chamber needs intervention. A worn or out-of-spec ring shows up first as drift in the outermost measurement sites:
The dominant wear mode is steady erosion of the upper surface and inner step by ion bombardment. As the ring thins, the sheath above it lowers, the edge ion angle changes and edge critical dimensions drift out of specification. This is the expected end-of-life mechanism and the reason ring height is tracked against RF hours.
Thermal cycling, mechanical handling and arc events can crack or chip the ring, particularly along the thinned inner edge late in life. Fractures alter the local field, create particle sources and can damage the wafer or chuck if fragments migrate. Any visible crack warrants immediate replacement.
Process polymer accumulates on the ring surface and in the wafer-to-ring gap. Heavy or flaking deposits cause defects, while a contaminated or poorly seated ring can disturb the RF return path and promote arcing, which locally damages the ring and destabilises edge plasma.
Focus ring replacement is a routine but precision-sensitive task that should follow the TEL maintenance procedure for the specific chamber. The following sequence summarises good practice and is not a substitute for the OEM manual:
Focus rings are scheduled consumables, so availability and consistency matter as much as the part itself. ESCT Fab Support stocks ES7099-216 as a qualified alternative to the OEM ring, helping fabs decouple their PM cadence from single-source supply constraints:
It surrounds the 300 mm wafer at the chuck edge and extends the plasma sheath beyond the silicon, keeping ion bombardment vertical at the wafer periphery. This protects edge etch profiles and uniformity, and provides a controlled RF return at the wafer edge.
No. ES7099-216 is supplied as a second-source NEW, OEM-compatible focus ring. It is verified to the form, fit and function of TEL OEM P/N 2L10-252706-11 but it is not an original Tokyo Electron branded part and is not sold as one.
Track ring height against accumulated RF hours and watch edge metrology. Drift in edge etch rate or critical dimension, rising edge particle counts, visible thinning, cracking or heavy polymer build-up all indicate the ring has reached end of life and should be swapped at the next PM.
Ring height sets the height of the plasma sheath above it, which controls the ion angle at the wafer edge. The “T12.1S” profile must match the qualified specification, because installing a ring of the wrong thickness shifts edge etch behaviour and breaks chamber matching.
When supplied to the correct material and dimensional specification and installed and reconditioned per the TEL procedure, the ring is intended to reproduce baseline edge performance. Consistent dimensional control across replacements is what keeps multiple chambers matched.
The typical lead time is 4-5 weeks. Because focus rings are scheduled consumables, we recommend aligning orders with your PM calendar and holding buffer stock to avoid unplanned downtime.
The Focus Ring 360-298.1-T12.1S (OEM P/N 2L10-252706-11, ESCT P/N ES7099-216) is an edge-confinement consumable for TEL 300 mm plasma etch chambers that shapes the plasma sheath, protects edge etch uniformity and provides a controlled RF return at the wafer periphery. Its thickness profile, material purity and erosion behaviour directly influence edge yield, particle performance and chamber matching, which is why qualified, predictable supply matters. As a second-source NEW alternative verified to OEM form, fit and function, ES7099-216 helps fabs sustain edge performance and PM discipline at a managed cost.
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 2L10-252706-11. 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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