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The Focus Ring (OEM P/N 3D10-250971-11, ESCT P/N ES7099-089) is a plasma-facing edge-confinement consumable used in Tokyo Electron (TEL) 300 mm plasma etch process chambers. As the descriptor “RING, FOCUS SH” with a “T4.5-TAPER306” profile indicates, this is a focus ring engineered with a specific tapered cross-section, a chamfered or sloped inner shoulder that steps down toward the wafer edge. The focus ring is one of the most safety-critical and yield-critical consumables in any capacitively coupled etch reactor, because it physically and electrically extends the wafer plane and shapes the plasma sheath precisely where edge-die uniformity is hardest to control.
In a TEL 300 mm etcher, the focus ring sits concentrically around the electrostatic chuck (ESC), circling the 300 mm wafer at its outer perimeter. It rests on, or is closely coupled to, the cathode assembly and the surrounding edge ring stack. During processing the ring is continuously bombarded by energetic ions and exposed to reactive fluorine- or chlorine-based chemistries, the same conditions that etch the wafer itself. Because of this, it is treated as a scheduled wear item with a finite life rather than a permanent fixture.
The tapered geometry encoded in the part name is not cosmetic. The angle and height of the taper tune how the electric field bends at the wafer edge, controlling the local ion incidence angle and the radial position of the plasma sheath boundary. A correctly profiled, fresh focus ring keeps the etch front vertical right out to the last few millimetres of the wafer; a worn or wrong-profile ring tilts the sheath, skews etch features at the edge and erodes edge-die yield.
The focus ring performs several simultaneous jobs at the wafer edge, all of which must hold within tight tolerances for the chamber to meet its uniformity and particle specifications:
Focus rings for TEL 300 mm etchers are manufactured from high-purity plasma-grade materials selected for predictable erosion and low contamination. Depending on the chamber and recipe, this is typically high-purity silicon, silicon carbide (SiC) or, in some applications, quartz. The chosen material determines both the erosion rate under ion bombardment and the chemical compatibility with the process gases in use.
Beyond raw material choice, the “T4.5” tapered profile is what makes this a part-specific consumable rather than a generic ring. The taper geometry, the ring height relative to the wafer surface and the bulk resistivity of the material together set the electrical coupling at the wafer edge.
Because the focus ring governs conditions exactly where edge dies live, its condition feeds directly into yield, throughput and chamber-matching metrics:
The dominant wear mode is gradual erosion of the ring’s upper surface and tapered inner edge under continuous ion bombardment. As material is sputtered away, the ring height drops and the taper geometry flattens, shifting the sheath inward and degrading edge uniformity. This is expected, progressive wear and is the normal reason for scheduled replacement.
Thermal cycling, mechanical handling and uneven seating can crack or chip silicon and quartz rings. A cracked ring is a serious particle and arcing risk: fractured fragments can land on the wafer or chuck, and a broken section can disturb the local field. Any ring showing cracks, chips or spalling should be removed from service immediately.
Polymer and etch by-product build-up on the ring surface can flake and generate particles, while contamination or poor contact at the seating face can cause localised arcing. Arcing damages both the ring and the components beneath it and is often a sign that the ring is overdue for replacement or that the seating surface needs cleaning.
Focus-ring replacement is a routine preventive-maintenance task, but it must follow the tool owner’s documented procedure. The following outline is typical for a TEL 300 mm etch chamber:
Focus rings are high-turn consumables, so a reliable, cost-effective supply line keeps preventive maintenance on schedule without inflating cost of ownership. ESCT Fab Support helps fabs and equipment refurbishers secure quality-verified focus rings for TEL platforms:
It surrounds the 300 mm wafer at its edge and shapes the plasma sheath there. Its tapered profile extends the wafer plane outward and controls the ion incidence angle at the perimeter, keeping etch rate and feature profiles uniform right out to the edge dies while protecting the chuck and cathode beneath it.
No. This is a new, second-source OEM-compatible focus ring, not an original Tokyo Electron part. It is manufactured and verified to match the form, fit and function of OEM P/N 3D10-250971-11 and is supplied under ESCT P/N ES7099-089.
The taper refers to the chamfered inner-edge geometry of the ring. The taper angle and step height tune how the electric field and plasma sheath behave at the wafer edge, so the ring must match the chamber’s intended profile. Using a ring with the correct taper holds edge uniformity.
Replacement interval depends on the process chemistry, RF power and recipe mix, so life is best defined by each fab’s preventive-maintenance data rather than a fixed figure. Rings are typically swapped on a scheduled PM cycle, or sooner if edge uniformity drifts or particle counts rise.
The typical lead time for ES7099-089 is approximately 4–5 weeks. Because focus rings are predictable, high-turn consumables, we recommend stocking ahead of planned PM cycles so replacements are always on hand.
The most reliable method is to match against the original equipment part number 3D10-250971-11 and confirm your chamber configuration with our team. Provide your tool model and chamber details and we will verify compatibility before you order.
The tapered Focus Ring (OEM P/N 3D10-250971-11, ESCT P/N ES7099-089) is a plasma-facing edge-confinement consumable for TEL 300 mm plasma etch chambers. Sitting around the wafer perimeter on the cathode assembly, it shapes the plasma sheath, controls edge ion incidence, confines the plasma and shields the chuck and cathode from ion bombardment. Its “T4.5” tapered profile makes it a part-specific item whose geometry must match the chamber, and as a scheduled wear part it has a direct and measurable effect on edge-die yield, particle performance and chamber matching. ESCT Fab Support offers it as a quality-verified, cost-effective replacement to keep preventive maintenance on track.
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 3D10-250971-11. 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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