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The focus ring supplied under ESCT P/N ES7099-205 is an annular plasma-facing consumable that sits concentrically around the 300 mm wafer on the lower electrode of a Tokyo Electron (TEL) plasma etch chamber. Identified by the OEM part number 2L10-252691-11 and the internal designation 311-T5.5G50L, it is one of the most replacement-intensive components in any high-volume etch fleet because it is positioned directly in the path of the plasma and the accelerated ion flux that does the etching work.
In a TEL 300 mm etch chamber, the wafer is clamped to an electrostatic chuck (ESC) and the focus ring encircles its outer edge, bridging the abrupt boundary between the wafer surface and the surrounding chamber hardware. Its central job is to extend the plasma sheath outward beyond the wafer so that the electric field, ion trajectories and etch behaviour seen by the outermost few millimetres of the wafer closely match those at the centre. Without a correctly profiled and electrically appropriate focus ring, the sheath collapses at the wafer edge, ions arrive at an angle rather than vertically, and edge die suffer tilted or distorted feature profiles.
Because the ring is consumed by the very process it enables, it is treated as a scheduled-replacement consumable rather than a durable assembly. Maintaining a qualified supply of focus rings is therefore central to keeping a TEL etch tool within its edge-uniformity and particle specifications between preventive-maintenance (PM) cycles.
The focus ring is a multi-function edge component. Although it looks like a simple flat ring, its profile, height and material properties are tuned to control the plasma at the most sensitive part of the wafer. Its principal roles include:
Focus rings for TEL 300 mm etch chambers are manufactured from plasma-resistant materials chosen to match the chemistry of the process and the lifetime demanded by the application. The 311-T5.5G50L ring is built to the dimensional and material conventions of this consumable class so that its erosion behaviour and electrical contribution track the original component.
The ring must survive continuous exposure to energetic ions and aggressive process gases while eroding in a slow, predictable and uniform manner. Typical performance characteristics of this consumable class include:
Beyond raw durability, the ring must hold its critical dimensions and electrical behaviour throughout its service life so the edge process stays in spec. Key attributes include:
Few consumables have as direct a line to edge-die yield as the focus ring. Because it shapes the plasma exactly where the wafer surface ends, even small changes in its height or condition show up immediately in edge metrology. A worn, mis-seated or incorrect focus ring can cause:
As a frontline consumable, the focus ring fails through wear rather than sudden breakage in normal operation. Understanding its degradation pattern is the key to setting the right replacement interval.
The dominant wear mode is gradual thinning under ion bombardment. As the ring loses height, the step relative to the wafer edge changes, the sheath profile shifts and the edge etch rate drifts. Once height loss exceeds the qualified window, edge uniformity can no longer be held by recipe compensation and the ring must be replaced.
Prolonged plasma exposure can roughen the ring surface, create micro-pitting, or cause localised flaking of redeposited material. These features become particle sources that contaminate the wafer edge and drive defectivity excursions, often before the ring reaches its geometric erosion limit.
Thermal cycling, mishandling during PM, or a ring that is not seated flat can lead to cracks or chipped edges. A poorly seated ring also disturbs thermal contact and RF coupling around the circumference, producing azimuthal non-uniformity. Any cracked, chipped or improperly seated ring should be removed from service immediately.
Focus-ring replacement is a routine but precision-sensitive PM task. The ring should only be changed by trained personnel following the relevant TEL maintenance procedure for the specific chamber. The general sequence is:
Because focus rings are consumed on a predictable cycle, fabs benefit from holding a qualified buffer stock rather than ordering reactively. ESCT supplies the ES7099-205 focus ring as a cost-effective, qualified alternative to sole-source OEM purchasing, with advantages that include:
It encircles the 300 mm wafer on the lower electrode and extends the plasma sheath beyond the wafer edge, so that the outermost die see the same vertical ion bombardment and etch behaviour as the wafer centre. This protects edge-die uniformity and shields the underlying electrode from wear.
No. ES7099-205 is supplied as a new, second-source, OEM-compatible focus ring. It is not an original TEL-branded part, but it is manufactured and verified to match the form, fit and function of OEM P/N 2L10-252691-11 so it can be used in its place.
This ring cross-references to TEL OEM P/N 2L10-252691-11, with the internal designation 311-T5.5G50L. Quoting either the OEM number or the ESCT number ES7099-205 gets the correct ring for your chamber configuration is identified.
Replacement frequency depends on the etch chemistry, RF power and run-rate, since the ring erodes continuously in service. Most fabs replace it on a defined PM interval driven by height-loss limits and edge-uniformity or particle monitor data rather than at a fixed calendar date.
The typical lead time for ES7099-205 is approximately 4–5 weeks. Because the focus ring is a consumable replaced on a routine basis, we recommend holding buffer stock and reordering ahead of need to align with planned PM cycles.
Focus rings are sacrificial consumables that erode during normal operation, so they are not generally reused once they reach their wear limit. This item is supplied new; running any focus ring past its qualified erosion window risks edge non-uniformity and particle excursions.
The ES7099-205 focus ring (TEL OEM P/N 2L10-252691-11, designation 311-T5.5G50L) is a critical edge-confinement consumable for TEL 300 mm plasma etch chambers. By extending the plasma sheath beyond the wafer edge and maintaining vertical ion incidence, it preserves edge-die etch uniformity, controls particle performance and protects the electrode beneath it. As a wear-driven part with a direct impact on yield, it should be held as qualified buffer stock and replaced on a disciplined PM schedule. Supplied as a new, second-source, OEM-compatible component verified to form, fit and function, it offers fabs a resilient, cost-effective alternative for keeping TEL etch tools within edge 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 2L10-252691-11. 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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