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The Focus Ring, N-Type (LLD) is a chamber consumable that sits in the outer annular zone of a Tokyo Electron 300 mm plasma etch chamber, surrounding the electrostatic chuck and the wafer it holds. Designated by TEL OEM part number 1810-225123-M1 and supplied by ESCT Fab Support as ES7099-163, it is one of the most directly process-critical parts in the chamber because it shapes the plasma sheath precisely where the wafer edge meets the surrounding hardware. The “N(LLD)” designation in the raw part name reflects a specific doping/conductivity grade and a particular chamber configuration variant, meaning this ring is not interchangeable with every focus ring in the catalogue, the doping level and dimensional profile are matched to a defined process and tool build.
A focus ring is fundamentally an electrical and geometric extension of the wafer. During etch, the RF-driven plasma forms a sheath above the wafer surface; without a surrounding ring of similar electrical character, the sheath would bend sharply at the wafer edge, distorting ion trajectories and ruining edge-die uniformity. The focus ring extends the effective electrode surface outward, holding the sheath flat across the last few millimetres of silicon and pushing the inevitable field distortion out beyond the device area and onto the consumable, where it can be tolerated and periodically replaced.
Because it is exposed to direct ion bombardment and reactive plasma chemistry throughout every wafer pass, the focus ring is a wear part with a finite service life. As it erodes, the sheath geometry it controls drifts, and edge etch performance degrades. Keeping a qualified replacement such as ES7099-163 on hand is therefore central to sustaining edge yield and predictable preventive-maintenance scheduling on TEL etch platforms.
In a TEL etch chamber the focus ring performs several overlapping functions simultaneously, electrical, geometric and thermal. Its specific N-type, LLD-configured form is engineered to balance all of these for a defined process window:
Focus rings of this class are produced from plasma-resistant, electrically defined materials, most commonly process-grade silicon with a controlled doping/conductivity specification, the property the “N-type” designation refers to. Material grade is not a cosmetic detail: it directly sets erosion rate, electrical behaviour and particle contribution.
The N-type doping grade gives the ring a controlled resistivity so its electrical character closely tracks that of the wafer it surrounds. This matching is what keeps the sheath continuous across the wafer-to-ring boundary and prevents abrupt field steps that would skew ion trajectories at the edge.
The ring must withstand sustained ion bombardment and reactive-species attack while shedding as few particles as possible. High purity and tightly controlled surface finish minimise defect generation and extend usable life before erosion shifts the process out of specification.
Because the focus ring governs conditions exactly where the most vulnerable edge dies are processed, its state has an outsized influence on yield and tool availability:
The dominant wear mechanism is gradual erosion under ion bombardment. As the ring thins and its inner profile recedes, the sheath geometry it once held flat begins to bend, edge etch rates shift and tilt appears in perimeter features. This is an expected end-of-life mode, which is why the ring is treated as a scheduled consumable rather than a permanent component.
Thermal cycling, mechanical handling and clamping stress can crack or chip the ring, particularly as it thins late in life. Fractures alter the local electrical field, generate particles and can in severe cases release fragments into the chamber, so replace it promptly once any damage is found.
Process by-products can accumulate on the ring surface, changing its effective dimensions and electrical behaviour. Build-up that later flakes becomes a particle source, and contamination of the ring surface can subtly alter the sheath and edge etch result before the part is even fully eroded.
Focus ring replacement is a routine but precision-sensitive preventive-maintenance task. Always follow the relevant TEL maintenance procedure for the specific tool and configuration; the following sequence summarises good practice:
Focus rings are high-turnover consumables, so a reliable second-source supply protects both budget and uptime. ESCT Fab Support offers ES7099-163 as a qualified alternative to the OEM ring with the practical advantages fabs need:
It extends the electrode surface and plasma sheath beyond the wafer edge, keeping the sheath flat across the outermost dies. This holds edge etch rate, profile and critical dimensions uniform and pushes unavoidable field distortion onto the consumable rather than the device area.
No. ES7099-163 is a second-source new part supplied by ESCT Fab Support as an OEM-compatible alternative to TEL part 1810-225123-M1. It is verified to match the original in form, fit and function but is not an original OEM-branded component.
It identifies a specific N-type conductivity grade and a particular chamber configuration variant. Because both the doping level and the dimensional profile are matched to a defined process and tool build, this ring should only be fitted where that exact variant is specified.
Service life depends on the process chemistry, RF power and run hours, so it is set by each fab’s own erosion data and PM schedule rather than a fixed figure. The ring is a consumable and is replaced once erosion begins to push edge etch performance toward the limits of its qualified window.
As the ring erodes, the sheath distorts at the wafer edge, causing edge etch-rate drift, tilted profiles and out-of-specification edge dies. Late-life cracking or particle shedding can also raise defect counts across the wafer, so timely replacement protects both yield and the surrounding hardware.
The typical lead time is 4-5 weeks. Because focus rings are recurring consumables, we recommend factoring this into PM stocking plans so a qualified replacement is always on the shelf when a ring change is due.
The Focus Ring, N-Type (LLD), TEL P/N 1810-225123-M1 (ESCT ES7099-163), is a process-critical edge consumable for Tokyo Electron 300 mm plasma etch chambers. By extending the electrode and plasma sheath beyond the wafer, it preserves edge etch uniformity, controls ion trajectories at the perimeter and protects the chuck and surrounding hardware from plasma attack. Its N-type doping grade and configuration-specific profile must be matched to the tool, and as a wear part it erodes predictably and must be replaced on schedule. Sourced from ESCT Fab Support as a verified second-source new part with a 4-5 week lead time, it offers a cost-effective, supply-resilient way to keep TEL etch tools running 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 1810-225123-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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