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The focus ring identified by Tokyo Electron part number 3D10-251946-11, and supplied by ESCT Fab Support under part number ES7099-140, is a precision annular consumable used in TEL 300 mm plasma etch process chambers. Designated in the OEM nomenclature as “RING, FOCUS JI ATCC-BSP8.3-75LR”, it is the ring of material that immediately surrounds the production wafer at the wafer edge, sitting on or adjacent to the electrostatic chuck. Its job is deceptively simple to describe but critically demanding in practice: to extend the plasma sheath and the surface chemistry of the wafer outward beyond the silicon edge, so that the very last few millimetres of the wafer etch as uniformly as the centre.
In a 300 mm etch tool, the wafer edge is the single most challenging region for process control. Without a focus ring, the electric field would terminate abruptly at the wafer rim, bending the ion trajectories and distorting the plasma sheath. The result is non-vertical etch profiles, tilted features, and degraded critical-dimension uniformity in the outermost dies, the dies that, on a 300 mm substrate, represent a disproportionately large fraction of total device count and revenue. The focus ring exists to push that field distortion off the wafer and onto a sacrificial component instead.
Because it is directly exposed to energetic ions, reactive radicals and elevated temperatures, the focus ring is a planned consumable: it erodes during normal operation and is replaced on a predictable schedule. Maintaining a reliable supply of qualified rings such as ES7099-140 is therefore central to keeping a TEL etch fleet matched, productive and within specification.
The focus ring is an electrically and chemically active member of the chamber’s edge assembly. Far from being a passive spacer, it shapes the plasma at the wafer boundary and participates in the RF circuit that drives the etch. Its principal functions include the following:
Focus rings for TEL 300 mm etch chambers are manufactured from high-purity, plasma-grade materials selected for their erosion behaviour, electrical properties and particle performance. The exact grade depends on the process the ring serves, but the engineering trade-offs are common across the family.
Depending on the application, focus rings are produced from high-purity silicon, silicon carbide, quartz or technical ceramics. Material choice is driven by etch chemistry: silicon and silicon carbide are favoured where the ring must be chemically compatible with the wafer surface and contribute minimal foreign-species contamination, while quartz and ceramics offer different erosion and dielectric characteristics.
The ring’s inner diameter, height, taper and flatness are tightly toleranced because they set the sheath geometry relative to the wafer plane. Even small deviations shift the field profile at the edge and degrade uniformity.
Because the focus ring governs the behaviour of the wafer edge, its condition has a direct and measurable effect on device yield and tool availability. As the ring erodes, the sheath geometry it was qualified to produce drifts, and edge performance degrades long before the ring fails outright:
The dominant wear mechanism is gradual erosion from continuous ion bombardment. As the ring’s upper surface and inner edge recede, the sheath drops relative to the wafer plane and edge uniformity drifts. This is expected behaviour and is the basis for the ring’s scheduled replacement interval; the key is to replace it before erosion pushes edge results out of specification.
Thermal cycling and mechanical handling can initiate cracks or chips, particularly in brittle silicon and ceramic rings. A fractured ring generates particles, can short or disturb the local RF path, and may break apart inside the chamber, risking damage to the chuck and other edge hardware. Handle it carefully during installation.
Over time the exposed surface roughens and process by-products or polymer films accumulate on the ring. This alters its electrical coupling and erosion rate, increases the likelihood of flaking, and contributes to defectivity. Rings showing heavy deposition or roughening should be replaced rather than reused beyond their qualified life.
Focus ring replacement is a routine preventive-maintenance activity, but it must be carried out with care to protect the chuck, preserve cleanliness and seat the new ring correctly. The following sequence reflects good practice; always follow the approved TEL procedure and site safety requirements for the specific tool.
Focus rings are high-frequency consumables, so the way a fab sources them has a direct bearing on cost per wafer and tool availability. ESCT Fab Support helps fabs and refurbishers keep TEL etch chambers running without over-committing capital to OEM-only supply chains. Choosing ES7099-140 through ESCT offers:
It surrounds the wafer at its edge and extends the plasma sheath outward, keeping ion trajectories vertical and the etch uniform right to the wafer rim. In doing so it protects yield in the outermost dies and shields the chuck from edge erosion.
No. ES7099-140 is supplied as a second-source, new part that is verified to the form, fit and function of TEL OEM P/N 3D10-251946-11. It is not an original OEM-branded component, but it is intended as a direct functional equivalent.
As a consumable, the ring is replaced on a scheduled interval determined by erosion rate, which depends on the process, RF power and run hours. Most fabs track edge uniformity and particle data and set a wafer-count or hour-based replacement limit before performance drifts out of specification.
Depending on the process, focus rings are produced from high-purity silicon, silicon carbide, quartz or technical ceramic. The material is chosen for plasma-erosion resistance, the correct electrical properties and minimal contamination of the wafer edge.
The typical lead time is 4-5 weeks. Because focus rings are consumed continuously, we recommend ordering ahead of need and holding buffer stock aligned to your preventive-maintenance schedule.
Match the TEL OEM part number 3D10-251946-11 against your tool’s bill of materials, and contact ESCT with your chamber and process details. Our team will confirm suitability for your specific TEL 300 mm etch platform before you order.
The focus ring (TEL P/N 3D10-251946-11, ESCT P/N ES7099-140) is a precision edge consumable that governs plasma confinement, sheath geometry and RF coupling at the wafer perimeter in Tokyo Electron 300 mm plasma etch chambers. By extending uniform etch behaviour to the very edge of the wafer and absorbing ion bombardment that would otherwise attack the chuck, it directly protects edge-die yield and tool availability. As a planned consumable subject to erosion, cracking and surface roughening, it must be replaced on a controlled schedule and re-qualified after each change. Sourcing it as a second-source new equivalent through ESCT Fab Support gives fabs reliable quality, competitive cost and a predictable 4-5 week lead time to keep their etch fleets matched and productive.
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 3D10-251946-11. 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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