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The TEL Focus Ring T4G50L-G2TMF (OEM part number 3D10-250807-21) is a consumable plasma-facing ring that sits on the chamber cathode assembly, immediately surrounding the 300 mm wafer in a Tokyo Electron plasma etch process chamber. As an edge-of-wafer focus ring, it extends the electrostatic chuck and the active plasma region outward beyond the wafer perimeter, so that the sheath geometry and ion trajectories at the wafer edge mirror the conditions seen across the wafer centre. The cryptic designation T4G50L-G2TMF identifies a specific ring profile, material grade and dimensional variant within TEL’s focus ring family; ESCT supplies it under part number ES7099-052.
In etch, the few millimetres at the wafer edge are the hardest region to control. Without a properly conditioned ring around the wafer, the plasma sheath bends inward at the edge, ions strike the outermost dies at an angle, and critical dimensions, etch depth and profile angle drift out of specification across the final ring of useful chips. The focus ring exists to push that distortion off the wafer and onto a sacrificial component, protecting yield on the edge dies that increasingly represent a meaningful fraction of each 300 mm wafer.
Because it is directly exposed to energetic ions, reactive radicals and RF fields, the focus ring is one of the fastest-eroding parts in the chamber. It is a scheduled consumable: it is consumed deliberately so that the wafer is not, and it must be replaced on a defined cadence to keep edge process results within control limits. Reliable supply of a verified, form-fit-function equivalent ring such as ES7099-052 is therefore central to keeping a TEL etch fleet running at qualified performance.
The focus ring is far more than a mechanical spacer around the wafer. It is an electrically and geometrically active element of the lower electrode that shapes the plasma where it matters most. Its principal functions in a Tokyo Electron 300 mm etch chamber include:
Focus rings for 300 mm etch are manufactured from process-matched materials, commonly high-purity silicon, silicon carbide or quartz depending on chemistry, chosen for plasma compatibility, predictable erosion behaviour and low particle generation. The material grade is integral to the T4G50L-G2TMF specification, because it determines both how the ring couples RF energy and how it ages in the chamber.
The ring is engineered to withstand sustained exposure to aggressive fluorine- and chlorine-based etch chemistries and high ion-energy bombardment without spalling, cracking or shedding contaminating particles. Key material attributes include:
Performance depends on the ring reproducing the OEM geometry and electrical characteristics precisely. Even small deviations shift the edge result. Critical parameters include:
Because the focus ring governs the edge sheath, its condition is directly visible in production data. As the ring erodes or if a non-conforming ring is fitted, the consequences propagate quickly to yield and tool availability:
The dominant wear mode is steady sputter erosion of the upper surface and inner step under ion bombardment. As the ring thins, its top surface drops below the wafer plane, the edge sheath bends inward and the etch result at the wafer perimeter drifts. This is the wear that drives the scheduled replacement interval and is tracked through RF parameters and edge metrology.
Repeated thermal cycling, mechanical handling and localised hot spots can cause micro-cracks that propagate into chips or fractures. A cracked ring sheds particles onto the wafer edge and can compromise seating and thermal contact, producing sudden defect excursions rather than the gradual drift of normal erosion.
Polymer and etch by-product redeposition on the ring, together with debris trapped under it, can lift the ring slightly or create uneven thermal contact with the cathode. The result is a non-uniform edge gap, flaking material and particle generation, which is why careful cleaning of the seating surface accompanies every ring change.
The focus ring should be changed during a planned preventive-maintenance window, following the tool owner’s documented procedure and contamination-control practices. A typical replacement sequence is:
Focus rings are high-turnover consumables, so a disciplined sparing strategy keeps chambers qualified and avoids unplanned downtime. Sourcing ES7099-052 through ESCT Fab Support gives fabs a dependable, cost-effective alternative to single-source OEM supply:
It surrounds the 300 mm wafer on the lower electrode and extends the plasma sheath beyond the wafer edge, keeping ion trajectories vertical and the etch result uniform on the outermost dies. It is a sacrificial component that absorbs ion bombardment so the wafer edge stays in specification.
No. This is a new, second-source part supplied by ESCT Fab Support as an OEM-compatible equivalent to TEL OEM P/N 3D10-250807-21. It is verified to the form, fit and function of the original but is not an original OEM-branded component.
The interval is process-dependent and is driven by accumulated RF hours and erosion rate under the specific chemistry and power used. Most fabs set a PM cadence based on tracked edge metrology and RF parameters, replacing the ring before height loss pushes edge results out of control limits.
Tell-tale signs include drift in edge critical dimension and profile angle, degraded within-wafer uniformity, rising edge particle or defect counts, and shifts in RF match or reflected power. Visible thinning, surface roughening or cracking on inspection also indicate the ring has reached end of life.
The current lead time is 4–5 weeks. Order against ESCT P/N ES7099-052, referencing TEL OEM P/N 3D10-250807-21 and your chamber configuration so we can confirm the correct ring variant for your process.
Any focus ring change, OEM or second-source, should be followed by chamber conditioning and re-qualification per your internal procedures. Because the ring is matched to OEM geometry and material, the goal is to return the chamber to its existing qualified window without process retuning.
The TEL Focus Ring T4G50L-G2TMF (OEM P/N 3D10-250807-21, ESCT P/N ES7099-052) is a critical edge consumable for Tokyo Electron 300 mm plasma etch chambers. By extending and shaping the plasma sheath at the wafer perimeter and serving as a sacrificial RF-coupling surface, it protects edge-die yield, etch uniformity and particle performance. As a predictably eroding part, it demands a disciplined replacement and sparing strategy. ESCT supplies this ring as a new, OEM-compatible alternative verified to form, fit and function, with a 4–5 week lead time, helping fabs maintain qualified etch performance while controlling consumable cost.
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 3D10-250807-21. 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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