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The component identified by the raw descriptor “RING, FOCUS SH T4.0-2TAPER306” is a plasma-etch focus ring used in Tokyo Electron (TEL) 300 mm process chambers. It is the annular consumable that surrounds the production wafer at the wafer plane, sitting directly on or immediately adjacent to the electrostatic chuck (ESC) edge. The “T4.0” and “2TAPER” portions of the descriptor refer to the ring’s profile geometry, a defined thickness class and a twin-tapered upper edge, while the “SH” designation links it to a shower-head style chamber configuration in which process gas is delivered through the upper electrode above the wafer.
In a plasma etch chamber, the wafer is an island within a much larger electrically and thermally active environment. The focus ring extends the wafer’s effective electrical and physical surface outward, so that the plasma sheath does not collapse abruptly at the wafer’s physical edge. Without this extension, the outermost few millimetres of every wafer would see a distorted sheath, a bent ion trajectory and an altered etch rate, precisely the region where yield is hardest to recover. The focus ring is therefore one of the most consequential consumables in the chamber despite its apparent simplicity.
This ES7099-079 ring is supplied as a 2nd Source, NEW component manufactured to match the form, fit and function of the TEL part 3D10-250968-11. The twin-taper geometry is substantial: the inner taper shapes the sheath profile over the wafer bevel, while the outer taper manages the transition to the surrounding chamber hardware and helps control where erosion and polymer deposition concentrate over the ring’s service life.
The focus ring performs several interlinked electrical, thermal and fluid-dynamic duties at the wafer edge. Its tapered, thickness-controlled profile is engineered so that the plasma sheath remains parallel to the wafer surface right out to the edge, keeping ion-incidence angles vertical where features would otherwise tilt. Its principal functions include:
Focus rings of this class are produced from high-purity etch-grade materials, typically single-crystal or polycrystalline silicon, or silicon carbide, depending on the process chemistry, chosen so that the ring erodes predictably without contaminating the wafer. The exact grade matters because the ring is directly in the plasma and any sputtered material becomes a potential particle or metallic-contamination source.
The ring must withstand sustained exposure to fluorine-, chlorine- or bromine-based plasmas and energetic ion bombardment while keeping trace-metal content extremely low. A silicon or silicon-carbide focus ring is process-compatible in this respect because its erosion products are consistent with the wafer chemistry rather than introducing foreign species.
The “T4.0” thickness class and the twin-taper profile must be held to tight tolerances. Even small deviations in ring height relative to the wafer surface change the local sheath shape and shift edge etch rate, so geometric fidelity to the original TEL profile is what gives matched chamber-to-chamber behaviour.
Because the focus ring governs the electrical and physical boundary conditions at the wafer edge, its condition feeds directly into edge yield, tool matching and overall productivity. A worn or out-of-spec ring degrades the very region where edge-exclusion rules are tightest and where each die carries full process value.
The dominant wear mechanism is gradual erosion from ion bombardment, which lowers the ring’s top surface relative to the wafer. As the ring recesses, the sheath bends down at the edge, ion trajectories tilt and edge etch rate drifts, the classic signature that a focus ring has reached end of life and must be replaced.
Repeated thermal cycling, localised arcing or mechanical mishandling during installation can crack a silicon or silicon-carbide ring. Cracks compromise both the electrical boundary and structural integrity, and any fragment that breaks free becomes an immediate, high-impact particle source on production wafers.
In polymerising chemistries, deposits accumulate on the ring surfaces, especially in the taper transitions. As these flake or roughen, they generate particles and alter the local RF and gas environment, contributing to edge defectivity and recipe instability between scheduled cleans.
Focus-ring replacement is a routine preventive-maintenance activity, but it must be carried out with strict contamination and handling discipline because the ring sits at the wafer plane. The following sequence reflects good practice; always defer to the applicable TEL maintenance procedure for the specific chamber.
Focus rings are high-frequency consumables, so securing a reliable, qualified supply is central to keeping etch chambers productive. ESCT Fab Support offers this ring (ES7099-079) as a cost-effective alternative to single-sourcing through the OEM, supporting both planned PM stocking and unplanned recovery.
It surrounds the wafer at the wafer plane and extends the electrical and physical surface outward so the plasma sheath stays flat across the wafer edge. This keeps ion trajectories vertical and edge etch rate uniform, protecting the outermost die where yield is most vulnerable.
No. This is a 2nd Source, NEW component supplied as an OEM-compatible replacement. It is manufactured to match the form, fit and function of TEL P/N 3D10-250968-11, but it is not an original Tokyo Electron part and is not sold as one.
Focus rings of this class are made from high-purity etch-grade materials such as silicon or silicon carbide, selected for plasma compatibility and predictable erosion. The correct grade wears consistently without contaminating the wafer edge.
The main indicators are measured height loss from erosion and a drift in edge etch rate, CD or profile uniformity. Visible cracking, chipping or heavy polymer build-up are also clear signals that the ring has reached end of life and should be changed at the next PM.
The inner and outer tapers shape the plasma sheath over the wafer bevel and manage the transition to the surrounding hardware. They also influence where erosion and deposition concentrate, so reproducing these angles faithfully is what gives matched, repeatable edge performance.
The typical lead time is 4-5 weeks. Because focus rings are consumed on a regular PM schedule, we recommend factoring this lead time into your spares planning and holding buffer stock to avoid unplanned chamber downtime.
The Focus Ring ES7099-079 (TEL P/N 3D10-250968-11) is a precision edge-confinement consumable for Tokyo Electron 300 mm plasma etch chambers of the shower-head configuration. Its T4.0 thickness class and twin-taper profile shape the plasma sheath at the wafer edge, keeping ion trajectories vertical and edge etch uniform while acting as a sacrificial barrier protecting the electrostatic chuck and surrounding hardware. As one of the most frequently replaced etch consumables, it has a direct bearing on edge yield, tool matching, particle performance and cost of ownership. Supplied NEW from a qualified second source to match the original form, fit and function, ES7099-079 gives fabs a dependable, cost-effective option for both planned PM stocking and rapid chamber recovery.
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 3D10-250968-11. 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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