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The Upper Focus Ring (Type L-205) is a precision annular consumable that sits in the upper portion of the wafer-edge assembly inside a Tokyo Electron 300 mm plasma etch chamber. Designated by TEL as an “UP” focus ring, it forms the upper boundary of the edge-confinement stack that surrounds the electrostatic chuck and the outer perimeter of the 300 mm wafer. In this position it works in concert with the lower focus ring, the insulator and the chamber liner to shape the plasma sheath as it bends over the wafer edge, so that the reactive ions arrive at the wafer perimeter with the same energy and angular distribution that they do at the centre.
Focus rings are among the most heavily consumed parts in any etch chamber because they live directly in the path of the plasma. The L-205 ring is continuously exposed to energetic ion bombardment, reactive fluorine- and chlorine-based chemistries and intense thermal cycling. Its profile, dielectric properties and dimensional accuracy determine whether the last few millimetres of the wafer, where a disproportionate share of high-value die reside, etch to specification or drift out of tolerance.
Because the ring is sacrificial by design, it is replaced on a defined preventive-maintenance schedule. Sourcing a dimensionally faithful, plasma-grade equivalent such as ESCT P/N ES7099-173 keeps tools running on their qualified recipes without waiting on extended OEM lead times.
The upper focus ring extends the effective electrical and physical surface of the wafer outward, so the plasma sheath does not collapse prematurely at the wafer edge. By controlling sheath curvature at the perimeter it directly governs edge-region etch results. Its principal functions include:
Upper focus rings of this class are manufactured from high-purity materials selected to survive aggressive etch chemistries while contributing minimal contamination. Depending on the recipe family, the chosen material balances dielectric behaviour, erosion resistance and particle performance:
The performance of the L-205 ring is inseparable from its geometry. The inner diameter, step height and seating face are machined to close tolerances because even small deviations change the local sheath shape and the gap to the wafer edge:
Because the upper focus ring controls conditions at the wafer perimeter, its condition propagates directly into device yield and tool availability. A worn, contaminated or out-of-specification ring produces measurable consequences:
The most fundamental failure mode is gradual erosion. Continuous ion bombardment thins the ring and recedes its critical step and inner-diameter surfaces over time. As the profile changes, the sheath shape at the wafer edge shifts, edge etch rates drift, and the ring eventually falls outside its usable dimensional window and must be replaced.
Repeated heating and cooling between plasma-on and plasma-off states imposes thermal-stress cycling. In brittle quartz and ceramic rings this can nucleate micro-cracks that propagate into chips or fractures, particularly around the seating face or thin step features. Mishandling during installation is a frequent trigger for premature cracking.
Polymer deposition, redeposited etch by-products and progressive surface roughening accumulate on the ring during production. As these layers build and the surface degrades, they can flake and release particles onto the wafer, raising defect counts and signalling that the ring has reached the end of its service life.
Focus-ring replacement should always follow the procedures defined in the relevant TEL maintenance documentation for the specific chamber. The general sequence below outlines good practice for swapping the L-205 upper focus ring:
Focus rings are recurring, scheduled consumables, so reliable supply and predictable lead times are central to keeping etch tools productive. ESCT Fab Support offers the L-205 upper focus ring (ES7099-173) as part of a broader edge-consumable programme designed to reduce risk and cost:
It is the upper ring in the wafer-edge confinement stack of a TEL 300 mm plasma etch chamber. It extends the plasma sheath beyond the wafer edge and shapes it so that ions strike the outermost die at the correct angle and energy, preserving edge-to-centre etch uniformity and protecting underlying chamber hardware.
No. This is a second-source new part, not an original Tokyo Electron component. It is supplied as a new OEM-compatible focus ring verified to match the form, fit and function of OEM P/N 1D10-350687-11, allowing it to be used in place of the original on qualified recipes.
Focus rings are sacrificial consumables, so replacement frequency depends on the chemistry, RF power and run hours of each process. Most fabs replace them on a defined preventive-maintenance interval tied to accumulated erosion or measured edge-uniformity drift rather than a fixed calendar date.
As the ring erodes, the plasma sheath at the wafer edge changes shape, causing edge etch-rate drift, tilted feature profiles and rising particle counts. The net effect is reduced edge die yield and growing process instability, with the risk of an unplanned tool stop if the ring fails outright.
The typical lead time is 4-5 weeks. Because focus rings are scheduled consumables, we recommend aligning orders with your preventive-maintenance plan and holding suitable buffer stock so a worn ring can be replaced without interrupting production.
Because the part is verified to the original form, fit and function, it is intended to drop into the same position and behave equivalently to the OEM ring. As with any consumable change, we recommend following your standard re-qualification and edge-uniformity verification steps after installation before returning to full production.
The Upper Focus Ring (Type L-205), OEM P/N 1D10-350687-11 and ESCT P/N ES7099-173, is a critical edge consumable for TEL 300 mm plasma etch chambers. Sitting at the top of the wafer-edge confinement stack, it shapes the plasma sheath over the wafer perimeter, governs edge etch uniformity, protects underlying hardware and absorbs erosion as a sacrificial component. Supplied as a second-source new part on a 4-5 week lead time, ES7099-173 gives fabs a dimensionally faithful, cost-effective alternative for keeping etch tools on their qualified recipes without extended OEM waits.
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 1D10-350687-11. 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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