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The focus ring supplied under ESCT P/N ES7099-117 (TEL OEM P/N 2L10-251854-11) is a circular plasma-facing consumable that surrounds the production wafer inside a Tokyo Electron 300 mm plasma etch chamber. It seats on the electrostatic chuck assembly at the wafer perimeter, forming a continuous annular ring around the 300 mm substrate. In this position the focus ring is one of the most heavily plasma-exposed components in the chamber, and its profile and electrical behaviour have a direct, measurable effect on how the etch process performs at the extreme edge of the wafer.
In TEL etch platforms the focus ring (sometimes referred to as the edge ring) performs the task that its name implies: it focuses and confines the plasma so that the sheath geometry extends smoothly past the wafer edge rather than collapsing or distorting at the substrate boundary. Without this ring, the plasma sheath would terminate abruptly at the conductive chuck edge, bending field lines and producing tilted, bowed or non-uniform etch features in the outermost few millimetres of every wafer. The focus ring effectively makes the wafer “look” larger to the plasma, pushing the discontinuity outward into a sacrificial part rather than into product silicon.
Because the focus ring is consumed by the very process it controls, it is a scheduled replacement item. As it erodes, the sheath geometry it once maintained drifts, and edge yield falls. The “REWORK” designation in the source description reflects that this part is offered as a precision-machined consumable conforming to the OEM form, fit and function, ready to drop into the existing ring set during a planned preventive-maintenance window.
The focus ring is not a passive spacer. It is an electrically and geometrically active element of the chamber that shapes the plasma sheath, manages RF coupling at the wafer edge and protects the underlying chuck hardware. Its principal functions include:
Focus rings for TEL 300 mm etch chambers are manufactured from plasma-grade materials selected for erosion resistance, dimensional stability and electrical compatibility with the surrounding chuck. The ring must hold a tightly toleranced profile through millions of RF cycles while remaining a clean source of process chemistry. The two performance dimensions that matter most are the bulk material behaviour and the geometric precision of the machined ring.
Edge consumables in this class are typically produced from high-purity silicon, silicon carbide or comparable plasma-grade ceramics depending on the chamber and process chemistry. The chosen material must resist sputter erosion and fluorine- or chlorine-based chemical attack while contributing only benign by-products to the discharge. Its purity directly governs metallic-contamination and particle performance at the wafer edge.
The ring’s inner diameter, height, step profile and flatness are machined to match the OEM specification so that the gap between the ring and the wafer edge, and the height relationship between ring top and wafer surface, reproduce the original sheath geometry. Small deviations in this profile translate directly into tilt and CD error at the edge.
Because the focus ring governs the electrical and geometric environment at the wafer boundary, its condition is one of the strongest determinants of edge yield and chamber-to-chamber matching. A worn, contaminated or out-of-specification ring produces effects that are felt across the whole production line:
As a sacrificial plasma-facing consumable, the focus ring is expected to wear; the engineering goal is to predict and schedule that wear rather than to be surprised by it. The dominant degradation mechanisms are described below.
Continuous ion bombardment gradually sputters material from the ring’s top surface and inner edge, lowering its height and widening the wafer-to-ring gap. This is the primary, intended wear mode: as the ring thins, the sheath step it created shrinks, edge etch behaviour drifts, and the ring eventually reaches the end of its qualified life and must be replaced.
Reactive halogen species and etch by-products attack the ring surface, roughening it and, in some chemistries, forming and re-depositing polymer films. A roughened or coated surface alters local plasma conditions and becomes a source of particles, degrading defect performance well before the ring is fully eroded.
Thermal cycling, mechanical mishandling during installation, or localised arcing can crack or chip the ring, especially at the thinned inner edge near end of life. Fractured fragments are a serious particle and scratch risk, and arc-damaged sites distort the local field, so any cracked or chipped ring should be removed from service immediately.
Focus-ring replacement is normally carried out during a scheduled preventive-maintenance window by trained technicians following the OEM service procedure for the specific TEL chamber. The following sequence summarises good practice and is not a substitute for the manufacturer documentation:
Focus rings are recurring consumables, so securing a reliable, cost-effective supply is central to keeping etch chambers in production and edge yield stable. ESCT Fab Support offers the focus ring under ES7099-117 as part of a broader strategy for sustaining TEL etch tools:
It surrounds the 300 mm wafer at its perimeter and shapes the plasma sheath so that ion flux reaches the wafer edge at the correct angle. In effect it extends the plasma boundary past the substrate, preserving edge etch uniformity and protecting the chuck hardware beneath it.
No. This focus ring is supplied as a new, second-source OEM-compatible part. It is verified to match the original TEL component in form, fit and function and cross-references OEM P/N 2L10-251854-11, but it is not an original OEM-branded part.
Replacement interval depends on the process chemistry, RF power and chamber duty cycle, so it is defined by accumulated RF hours or wafer count rather than a fixed calendar date. The ring is changed during scheduled preventive maintenance once erosion and height loss begin to push edge performance toward its control limits.
As the ring thins, the sheath geometry drifts and edge critical dimensions, etch depth and feature profiles degrade, expanding the edge-exclusion zone and lowering yield. A heavily eroded or cracked ring also raises particle counts and risks chuck damage, which can turn a routine consumable change into an unplanned chamber repair.
The current lead time is 4-5 weeks. Because focus rings are high-turnover consumables, many fabs hold a buffer stock of ring sets so that maintenance windows are never delayed waiting on incoming parts; we can advise on appropriate stocking levels for your tool fleet.
When installed correctly and qualified with the standard conditioning and matching recipes, a part held to the OEM profile supports consistent edge behaviour across chambers. Good practice is to track ring life per chamber and rotate replacements so that no single tool drifts out of step with the rest of the fleet.
The focus ring offered under ESCT P/N ES7099-117 (TEL OEM P/N 2L10-251854-11) is a critical plasma-facing consumable for Tokyo Electron 300 mm plasma etch chambers. Seated at the wafer perimeter, it shapes and confines the plasma sheath, manages the RF environment at the wafer edge and protects the electrostatic chuck, directly governing edge etch uniformity, particle performance and edge yield. As a sacrificial part it erodes predictably and is replaced on a planned preventive-maintenance schedule. Supplied as a new, second-source part verified to the OEM form, fit and function with a 4-5 week lead time, ES7099-117 is a practical, cost-effective way to keep TEL etch chambers running on specification.
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 2L10-251854-11. 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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