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The Silicon Outer Electrode Ring (OEM P/N 839-020965-005) is a plasma-facing consumable that encircles the wafer-bearing inner electrode within a LAM capacitively-coupled etch chamber. Machined from high-purity silicon, the ring forms the outer annulus of the powered electrode assembly, extending the conductive electrode surface radially beyond the wafer edge so that the radio-frequency (RF) field and the overlying plasma sheath remain continuous and symmetrical across the full diameter of the substrate. The “FLEX45” designation ties the part to a specific chamber generation and electrode geometry, where the outer electrode profile is tuned to the gap, sheath and gas-flow conditions of that platform.
In a parallel-plate or capacitively-coupled etch reactor, the wafer rarely occupies the entire electrode area. Without a conductive surround, the electric field would distort sharply at the wafer perimeter, bending the ion trajectories and collapsing edge etch uniformity. The outer electrode ring solves this by presenting the plasma with an electrode boundary that behaves, electrically and geometrically, as a smooth continuation of the inner electrode. Using silicon for this ring, rather than an oxide or coated metal, means the surround is chemically compatible with fluorine- and chlorine-based etch chemistries, contributes only silicon-bearing species to the plasma, and erodes in a controlled, predictable manner instead of releasing metallic or particulate contamination.
As a directly plasma-exposed and ion-bombarded component, the outer electrode ring is a scheduled consumable. Its surface condition, thickness and electrical continuity drift over chamber hours, and those drifts show up first as edge-of-wafer etch-rate and critical-dimension variation. Maintaining a known-good ring in the chamber is therefore central to holding edge yield and to keeping the recipe inside its qualified process window.
The ring is far more than a passive spacer around the wafer. It is an active part of the RF electrode and of the plasma confinement scheme, and several distinct functions are bound up in its geometry, purity and surface state.
The ring is machined from high-purity silicon precisely because the chamber chemistry demands it. Under fluorine and chlorine plasmas, silicon reacts to form volatile species that are pumped away cleanly, so the ring erodes without depositing involatile residues or shedding metallic contamination onto the wafer. Tight control of bulk resistivity and trace-metal content keeps the ring’s electrical behaviour and contamination signature consistent from part to part.
Field uniformity at the wafer edge is sensitive to the ring’s profile, flatness, inner and outer diameters, and surface finish. The FLEX45 geometry must be reproduced faithfully so the installed ring matches the electrode gap and sheath conditions the recipe was qualified against. Surface texture is controlled to manage erosion rate and to discourage flaking as the ring ages.
Because the outer electrode ring sits exactly where edge field, sheath and chemistry meet, its condition propagates directly into device-level results at the wafer perimeter, where a meaningful fraction of saleable die live.
The dominant wear mechanism is steady erosion under ion bombardment and chemical attack. As the silicon thins, the electrode gap and sheath profile at the wafer edge shift, edge etch rates drift, and the ring eventually falls outside the dimensional limits at which the recipe stays qualified.
Silicon is hard but brittle. Thermal cycling between idle and high-power states, plus the localised stress of an eroded or non-uniformly seated ring, can initiate cracks. A fractured ring disrupts the field, generates large particles and may require an unscheduled chamber-open and wet clean.
Late in life the eroded surface roughens, and re-deposited films at the ring edge can flake. Both raise the on-wafer particle count, pushing defect excursions at the wafer edge and signalling that the ring has reached the end of its useful service interval.
Replacement is a scheduled preventive-maintenance activity. Follow the tool owner’s documented procedure; the sequence below is a general guide and should be adapted to local protocols.
Plasma-facing silicon parts are recurring spends with a direct line to edge yield, so sourcing strategy matters as much as the part itself. ESCT Fab Support supplies this ring as a verified, fab-ready alternative to single-source OEM procurement.
It extends the powered electrode surface beyond the wafer edge so the RF field and plasma sheath stay continuous and uniform across the whole wafer. This corrects edge field distortion, supports edge plasma confinement, and provides a controlled, sacrificial silicon surface that erodes cleanly rather than contaminating the wafer.
No. This ring is supplied as a new, second-source, OEM-compatible component. It is manufactured and verified to match the form, fit and function of OEM P/N 839-020965-005, but it is not an original OEM-branded part.
ESCT P/N ES2099-044 is the catalogue reference for this component and cross-references directly to OEM P/N 839-020965-005. Quoting either number identifies the same FLEX45 silicon outer electrode ring.
As a plasma-exposed consumable, it is replaced on a wear-driven schedule rather than at a fixed calendar interval. Service life depends on recipe power, chemistry and chamber hours; fabs typically tie replacement to monitored edge uniformity, particle trends and measured ring thickness.
The typical lead time is 4-5 weeks. We recommend aligning orders with your preventive-maintenance planning and holding appropriate safety stock for a consumable on this kind of replacement cadence.
High purity keeps metallic and particulate contamination off the wafer, and the ring erodes into volatile, pump-friendly species under fluorine and chlorine chemistries. It also keeps the ring’s electrical behaviour consistent, which gives repeatable edge field shaping and tool-to-tool matching.
The Silicon Outer Electrode Ring in the FLEX45 configuration (OEM P/N 839-020965-005, ESCT P/N ES2099-044) is a high-purity silicon consumable that extends the powered electrode beyond the wafer edge, shaping the RF field and plasma sheath to protect edge etch uniformity, profile control and particle performance. It wears through erosion, thinning, cracking and surface roughening, tying scheduled replacement with a known-good ring to sustained edge yield. ESCT Fab Support supplies it as a new, second-source, OEM-compatible part verified to form, fit and function, with a clear cross-reference and a typical 4-5 week lead time.
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 Lam Research part number 839-020965-005. It is not an original OEM part and is not sold as one. It is not manufactured by, endorsed by, or affiliated with Lam Research, and all manufacturer names and part numbers are quoted for identification and compatibility purposes only.
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