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The Silicon Focus Ring is a high-purity single-crystal or polysilicon consumable that encircles the 300 mm wafer inside a Tokyo Electron (TEL) plasma etch process chamber. Seated on the electrostatic chuck (ESC) assembly, just outboard of the wafer edge, it forms the immediate boundary between the silicon being processed and the surrounding ceramic and quartz hardware. Because it is made from the same material as the wafer itself, it behaves electrically and chemically as an extension of the wafer’s surface, allowing the plasma sheath to bend smoothly across the wafer-to-ring transition rather than terminating abruptly at the substrate edge.
In a TEL etch chamber, the focus ring is one of the most influential consumables governing edge die yield. It shapes the electric field and ion trajectories over the outermost few millimetres of the wafer, where the wafer normally suffers from terminating field lines and divergent ion angles. By extending the conductive silicon surface beyond the wafer perimeter, the ring “pushes” the sheath edge outward, keeping the etch profile vertical and the etch rate uniform right out to the wafer edge exclusion zone.
As a sacrificial, plasma-facing part, the silicon focus ring erodes with every RF hour and must be tracked, qualified and replaced on a defined schedule. The ESCT Fab Support equivalent, P/N ES7099-051, is offered as a second-source new part verified to the form, fit and function of TEL OEM P/N 1810-329156-11, giving fabs a supply-assured alternative for this critical edge-ring position.
The focus ring is not a passive spacer; it is an active participant in plasma sheath formation and ion-flux management at the wafer edge. Its silicon composition, height, inner diameter and resistivity are all tuned to a specific TEL chamber and process recipe so that the edge of the wafer sees the same conditions as the wafer centre. Within the platform it performs several interlocking functions:
The behaviour of a focus ring is dominated by its material grade and its dimensional stability under continuous plasma exposure. Silicon is chosen specifically because it is chemically and electrically matched to the wafer, etches predictably in fluorine- and chlorine-based chemistries, and contributes no foreign metallic contamination to the process.
Process performance depends on controlling the silicon’s bulk and surface properties so that the ring couples RF energy and shapes the sheath identically from part to part.
Because the ring sits in intimate contact with the wafer edge and the chuck, its geometry and thermal coupling directly set the edge process window.
Few consumables have as direct a line to edge-die yield as the focus ring. As it erodes, its height drops and its inner profile changes, progressively altering the sheath geometry the wafer edge sees. The downstream consequences of a worn, mismatched or out-of-spec ring include:
The dominant wear mechanism is gradual sputter and chemical erosion of the silicon by energetic ions and reactive species. As the ring thins, its top surface recedes below the wafer plane, the sheath over the wafer edge reshapes, and edge CD and profile drift out of specification, the primary reason rings are replaced on an RF-hour or wafer-count schedule.
Silicon is brittle, and thermal cycling, mechanical handling or uneven seating can initiate micro-cracks that propagate into chips or fractures. A cracked or chipped ring sheds particles onto the wafer edge and chamber surfaces, driving defectivity excursions and, in severe cases, requiring an unscheduled chamber wet clean.
In polymerising chemistries, etch by-products can deposit on the ring surface and at its interfaces. Accumulated polymer roughens the surface, alters local RF coupling and thermal contact, and can later flake during plasma or thermal transients, becoming a moving source of particles and edge contamination.
Focus ring replacement is a routine but precision preventive-maintenance task that should follow the TEL chamber’s documented PM procedure and your fab’s contamination-control practices. The following sequence summarises good practice:
Focus rings are high-turnover consumables, so a dependable second source protects both uptime and budget. Sourcing ES7099-051 through ESCT Fab Support gives etch and PM teams a planned, qualified alternative to single-vendor dependency:
It surrounds the 300 mm wafer on the electrostatic chuck and extends the conductive silicon surface beyond the wafer edge. This shapes the plasma sheath and ion trajectories so the outermost die etch with the same profile and rate as the centre, protecting edge CD uniformity and yield.
No. ES7099-051 is supplied as a second-source new part that is OEM-compatible and verified to the form, fit and function of TEL OEM P/N 1810-329156-11. It is not an original Tokyo Electron OEM component and is not sold as such.
Silicon matches the wafer chemically and electrically, so it couples RF and shapes the sheath as a natural extension of the wafer surface and etches predictably without introducing metallic contamination. Ceramic and quartz parts serve different confinement and insulation roles elsewhere in the chamber.
Rings are normally replaced on an RF-hour or wafer-count schedule defined by erosion-driven height loss. Practical indicators include edge CD or profile drift, declining centre-to-edge uniformity, rising edge particle counts, and visible thinning, chipping or surface roughening at PM inspection.
The typical lead time is 4–5 weeks. We recommend aligning order timing with your preventive-maintenance cadence and holding buffer stock for this consumable so a scheduled or unscheduled ring change never waits on supply.
Any focus ring change alters the edge environment, so the chamber should be seasoned and re-qualified after installation. Running your standard edge CD, uniformity and particle qualification wafers confirms the new ring brings the chamber back within its established process window.
The Silicon Focus Ring (TEL OEM P/N 1810-329156-11, ESCT P/N ES7099-051) is a plasma-facing edge consumable that governs sheath shape, ion angle and etch uniformity over the outermost die of every 300 mm wafer processed in a TEL etch chamber. Its purity, resistivity and dimensional stability determine edge CD control, particle performance and edge-die yield, while its sacrificial erosion makes disciplined tracking, replacement and re-qualification necessary. As a second-source new, OEM-compatible part with a 4–5 week lead time, ES7099-051 gives fabs a supply-assured, cost-effective alternative for this critical process-kit position.
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 1810-329156-11. 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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