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The Focus Ring supplied under ESCT part number ES7099-154 is an annular plasma-facing consumable used in Tokyo Electron (TEL) 300 mm plasma etch process chambers. It corresponds to TEL OEM part number 2L10-252319-11 and is identified in TEL service nomenclature by the descriptor “RING, FOCUS LAB 360-312-5”. The focus ring surrounds the production wafer on the lower electrode assembly, sitting concentric with and immediately outboard of the 300 mm wafer it protects. Its job is to extend the active process region beyond the wafer edge so that the plasma behaves consistently from the centre of the wafer all the way to its outermost die.
In a plasma etch chamber, the wafer edge is the single most difficult region to control. Without a sacrificial ring to carry the plasma sheath past the wafer boundary, the electric field lines curve sharply at the wafer perimeter, the ion trajectories tilt inward, and the etch rate and profile degrade across the last several millimetres of usable silicon. The focus ring solves this by presenting a continuous, electrically and dimensionally matched surface around the wafer so that the sheath remains flat and the ions continue to strike the surface vertically right up to the wafer edge.
Because it is mounted directly in the path of the plasma and the ion flux, the focus ring is a scheduled wear item. It erodes over time, changes the sheath geometry as it thins, and must be replaced on a defined preventive maintenance interval to keep edge yield within specification. ESCT Fab Support offers this ring as a cost-effective, fit-and-function equivalent to the TEL original, helping fabs maintain consumable inventory without the lead-time and pricing constraints of single-source OEM supply.
The focus ring performs several interlocking functions, all of which influence the quality of the etch at the wafer edge and the cleanliness of the chamber environment as a whole:
Focus rings for TEL etch chambers are manufactured from process-compatible materials chosen for their plasma resistance, electrical characteristics and low particle generation. The performance of the ring is governed both by the bulk material and by the precision of its machined geometry.
Depending on the specific process recipe and chamber generation, focus rings of this type are produced from high-purity silicon, silicon carbide or comparable etch-grade ceramics. These materials are selected so that the ring erodes predictably and cleanly under fluorine- or chlorine-based plasmas without contaminating the wafer.
The functional value of a focus ring depends as much on its dimensions as on its material. The inner diameter, height step relative to the wafer plane, flatness and surface finish all directly shape the sheath at the wafer edge, so machining tolerances have to be tight.
Because the focus ring directly governs the plasma environment at the wafer edge, its condition has an outsized effect on edge yield and overall tool stability. As the ring wears or if a non-conforming ring is installed, several measurable consequences follow:
The dominant wear mode is gradual erosion of the ring surface under continuous ion bombardment. As the ring thins, the step height relative to the wafer changes, the sheath drops at the edge and edge etch performance steadily shifts out of specification, the primary reason the ring is replaced on a preventive maintenance schedule.
Thermal cycling, mechanical handling and the brittleness of silicon and ceramic materials can cause cracks or edge chips. A cracked ring generates particles, can seat unevenly and creates localised field disturbances that produce arcing and edge defectivity, requiring immediate replacement.
Polymer build-up and micro-roughening of the plasma-facing surface change the local electrical and thermal behaviour of the ring. This can trigger arcing, flake-induced particle excursions and inconsistent coupling, all of which compromise edge uniformity before the nominal erosion limit is reached.
Focus ring replacement should be carried out by trained personnel during a planned preventive maintenance window, following the relevant TEL chamber procedure. The following sequence outlines the typical workflow:
Because the focus ring is a recurring consumable consumed on every chamber, maintaining a reliable supply is central to fab uptime and cost control. ESCT Fab Support helps fabs secure that supply with a second-source offering that meets the form, fit and function of the TEL original:
It surrounds the 300 mm wafer on the lower electrode and extends the plasma sheath beyond the wafer edge, keeping the sheath flat and the ions vertical so that etch rate, profile and critical dimension stay uniform across the wafer perimeter.
No. This focus ring is supplied as a new, second-source OEM-compatible part. It is not an original Tokyo Electron component, but it is manufactured and verified to meet the form, fit and function of TEL OEM P/N 2L10-252319-11.
The Tokyo Electron OEM part number is 2L10-252319-11, identified in service records as “RING, FOCUS LAB 360-312-5”. The ESCT Fab Support reference is ES7099-154, which can be used for quoting and reordering.
As a sacrificial consumable, the ring is replaced on a preventive maintenance schedule defined by erosion rate and edge process drift. The exact interval depends on the recipe, power level and run hours, and is best set from each fab’s own etch data and edge yield monitoring.
The typical lead time for this focus ring is 4–5 weeks. We recommend planning consumable orders against your PM cadence so that buffer stock is on hand before the scheduled replacement.
Watch for drifting edge etch rate and critical dimension, increasing edge profile tilt, rising particle counts and any arcing events. Visual inspection at PM for thinning, cracking, chipping or heavy deposition confirms whether the ring should be replaced.
The Focus Ring (ESCT P/N ES7099-154, TEL OEM P/N 2L10-252319-11) is a precision plasma-facing consumable that controls the plasma sheath at the wafer edge in TEL 300 mm etch chambers. By extending the sheath beyond the 300 mm wafer and maintaining vertical ion incidence, it protects edge etch uniformity, critical dimension and yield. As a sacrificial item subject to erosion, cracking and surface degradation, it is replaced on a planned PM schedule. ESCT Fab Support supplies it as a new, fit-and-function second-source alternative with a 4–5 week lead time, helping fabs maintain consumable availability and control 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 2L10-252319-11. 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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