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The component identified by the raw descriptor “RING, F-8SO-SI-260-3.4A” is a silicon focus ring used in Tokyo Electron (TEL) 300 mm plasma etch process chambers. The “F” designation marks it as a focus (edge) ring, the “SI” element confirms a silicon construction, and the numeric fields encode the nominal ring geometry, an outer working diameter in the region of 260 mm sitting around a 300 mm wafer pocket, with a profile thickness on the order of 3.4 mm. It is a sacrificial consumable that seats concentrically around the electrostatic chuck, framing the wafer edge directly within the plasma sheath.
In a TEL capacitively coupled etch chamber, the focus ring is one of the most influential parts governing what happens at the outermost few millimetres of the wafer. It extends the plasma-facing surface beyond the wafer perimeter so that the sheath does not collapse abruptly at the wafer edge. By doing so it pulls the ion trajectories that strike the edge die back toward vertical, preserving feature profile and critical-dimension control where edge yield is hardest to win.
Because it is silicon, chemically similar to the wafer it protects, the ring erodes under the same fluorine and bromine plasma chemistries that drive the process, and it does so in a predictable, low-contamination manner. That makes it a planned wear item rather than a failure-prone assembly, but its condition has a direct and continuous effect on edge etch rate, uniformity and particle performance, which is why fab process teams track and rotate it on a defined schedule.
The silicon focus ring performs several overlapping electrical, plasma and mechanical functions simultaneously. Its position at the wafer edge means small changes in its height, profile or resistivity translate into measurable shifts in edge process results across the chamber.
The ring is machined from process-grade silicon, typically high-purity polycrystalline or single-crystal material, selected so that its erosion products are the same benign species already present in a silicon etch environment. Resistivity, grain structure and surface finish are controlled to keep the ring electrically consistent unit to unit and to avoid arcing or hot spots at the edge.
Under fluorine- and bromine-based chemistries the ring is consumed gradually from its upper surface, lowering its height over thousands of RF hours. As it thins, the sheath at the edge reshapes and edge etch rate and profile drift, which is why the ring is treated as a tuning surface as well as a protective one.
Because the focus ring sits exactly where edge yield is most fragile, its condition propagates straight into the fab’s key process and cost metrics. A worn, cracked or mismatched ring will show up first as edge-region drift long before it triggers an obvious chamber fault.
The dominant and intended wear mode is gradual surface erosion that reduces ring height. As the upper profile recedes the edge sheath drops, edge etch rate climbs and profile tilts inward; once the height falls outside the qualified window the ring must be replaced to restore edge uniformity.
Silicon is brittle, so thermal cycling, mechanical mishandling during a wet clean, or a wafer-placement misalignment can crack or chip the ring. Fragments and fresh fracture faces become particle sources at the wafer edge and can also disturb the local sheath, so any visible damage is cause for immediate replacement.
Polymer and by-product films can accumulate on the ring and, if uneven, distort the local electric field. In severe cases this produces micro-arcing at the wafer edge, leaving pits that accelerate erosion and seed defects, so deposition state is checked alongside height during preventive maintenance.
Replacement should be carried out during scheduled preventive maintenance by a trained technician following the relevant TEL chamber procedure. The steps below summarise good practice; always defer to the tool’s controlled work instructions and contamination-control protocols.
Because focus rings are recurring wear items consumed on a known cadence, they are ideal candidates for a managed second-source supply programme. ESCT Fab Support offers this silicon focus ring as a verified OEM-compatible alternative, giving fabs a way to control consumable spend without compromising edge performance.
It frames the wafer at the edge and extends the plasma sheath outward, keeping ion bombardment vertical and the electric field uniform across the outermost die. This protects edge critical-dimension control and profile, and the silicon also acts as a sacrificial, low-contamination surface.
No. It is supplied as a new, second-source component that is OEM-compatible and verified to the form, fit and function of TEL OEM P/N 1D10-309946-M1. It is not an original OEM part and is not sold as one.
It is machined from high-purity silicon, chosen so that its erosion products match the silicon etch environment and contribute minimal contamination. Resistivity, flatness and surface finish are controlled to keep edge electrical behaviour consistent.
Replace it when ring height has eroded outside the qualified window, when edge etch-rate or uniformity drift appears, or whenever cracks, chips or heavy uneven deposition are found during preventive maintenance. Most fabs rotate the ring on an RF-hour or wafer-count interval.
The typical lead time is 4–5 weeks. As this is a recurring consumable, we recommend aligning orders with your preventive-maintenance calendar and holding a buffer stock to avoid unplanned downtime.
When installed and requalified correctly, a dimensionally and electrically consistent ring supports good chamber-to-chamber matching. The main risk to matching is running rings at very different wear states, so consistent rotation and qualification across chambers is the key practice.
The silicon focus ring (TEL OEM P/N 1D10-309946-M1, ESCT P/N ES7099-148) is a sacrificial edge consumable that governs sheath shape, ion incidence and RF coupling at the wafer perimeter in TEL 300 mm plasma etch chambers. Its condition feeds directly into edge critical-dimension uniformity, profile, particle performance and chamber matching, making disciplined wear tracking and timely replacement necessary. Supplied as a new, OEM-compatible second-source part with a 4–5 week lead time, it gives fabs a reliable, cost-effective way to keep edge etch performance within 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 1D10-309946-M1. 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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