2L10-251992-11
CEL,OUTER ST-P(NEST)V2

Outer cell electrode ring, ST-P nest V2 (OEM P/N 2L10-251992-11), silicon outer electrode ring for TEL 300 mm plasma etch systems

ESCT Fab Support P/N ES7099-128, 2nd source NEW outer cell electrode ring for Tokyo Electron (TEL) plasma etch chambers

The Outer Cell Electrode Ring (TEL designation “CEL, OUTER” in the ST-P nest configuration, version V2) is a consumable silicon electrode component that sits at the outer perimeter of the cathode assembly inside a Tokyo Electron 300 mm plasma etch chamber. In TEL terminology the “CEL” denotes the cell electrode, the silicon electrode surface that forms part of the powered cathode stack and is directly exposed to the plasma. The “OUTER” element of this assembly is the annular ring that frames the central electrode plate, while “(NEST)” refers to the recessed seat that locates and registers the ring within the lower electrode housing. This component carries OEM P/N 2L10-251992-11 and is supplied by ESCT Fab Support under part number ES7099-128.

Positioned concentrically around the wafer-bearing region of the lower electrode, the outer cell electrode ring works alongside the inner electrode and the surrounding focus and edge rings to define the boundary conditions of the plasma sheath at the wafer edge. It is one of the parts that determines how cleanly the RF field, gas chemistry and ion flux behave across the outermost annulus of a 300 mm substrate, precisely the zone where etch uniformity is hardest to hold and where edge die yield is most easily lost.

Because it is fabricated from high-purity silicon and is continuously bombarded by energetic ions, the outer cell electrode ring is a true consumable. It erodes predictably with accumulated RF hours, and its condition has a direct, measurable effect on edge etch rate, profile control and particle performance. Keeping a qualified replacement on hand is part of disciplined chamber-matching and preventive-maintenance practice.

Functional role of the outer cell electrode ring in TEL plasma etch platforms

The outer cell electrode ring is far more than a passive spacer. As a powered silicon surface at the chamber periphery, it participates directly in plasma generation and confinement at the wafer edge. Its principal functions include the following:

• Extending the powered electrode surface outboard of the wafer so the plasma sheath remains uniform across the full 300 mm diameter rather than collapsing at the edge.
• Shaping the radial electric field and sheath geometry at the wafer perimeter to control ion incidence angle and minimise edge profile tilt.
• Providing a defined RF return and current path through the cathode stack, helping to stabilise impedance and power coupling.
• Acting as a silicon scavenging surface that participates in fluorocarbon chemistry, helping to balance polymer deposition and etch at the edge.
• Seating accurately into the (NEST) recess so the electrode stack maintains consistent height, concentricity and thermal contact from chamber to chamber.
• Protecting the underlying anodised aluminium electrode hardware from direct plasma attack, extending the service life of the more costly base components.

Material and process performance

The performance of an outer cell electrode ring is dictated by the purity and structural quality of the silicon used and by the dimensional precision of the machined geometry. Both characteristics govern how the part behaves under continuous plasma exposure.

Silicon purity and plasma resistance

The ring is produced from high-resistivity, high-purity silicon so that it erodes cleanly under fluorine and fluorocarbon plasmas without shedding metallic contaminants onto the wafer.

• Low trace-metal content to avoid mobile-ion and metallic contamination of the device edge.
• Controlled resistivity so the ring couples RF power consistently and behaves identically across matched chambers.
• Predictable, uniform erosion that keeps edge etch behaviour stable across the maintenance interval.

Dimensional and surface precision

Flatness, concentricity, ring thickness and surface finish are held to tight tolerances so the part registers correctly in the nest and presents a repeatable electrode surface to the plasma.

• Precise outer and inner diameters for a positive fit into the (NEST) seat without rock or lateral play.
• Tight thickness control to preserve electrode-stack height and the wafer-to-ring step at the edge.
• Consistent surface finish to deliver uniform secondary-electron and sputter behaviour and predictable particle generation.

Impact on tool performance and yield

Because the outer cell electrode ring governs the electrical and chemical environment at the wafer edge, its condition translates almost directly into edge-die outcomes. A worn, cracked or out-of-spec ring produces consequences that are felt across the process window:

• Edge-to-centre etch-rate drift and rising non-uniformity as the ring profile erodes away from its qualified geometry.
• Profile tilt, CD shift and tapering on the outermost die where sheath shaping is most sensitive.
• Increased particle counts and edge defects as silicon erodes unevenly or the surface roughens.
• RF impedance shifts that destabilise power coupling and complicate chamber-to-chamber matching.
• Shortened mean time between cleans and unplanned tool downtime when degradation goes unmanaged.

Common wear and failure modes

Plasma erosion and thinning

Continuous ion bombardment steadily sputters silicon from the exposed surface. As the ring thins and its edge profile rounds, the sheath geometry at the wafer perimeter changes and edge uniformity drifts, the dominant, end-of-life wear mode for this consumable.

Cracking and chipping

Silicon is brittle, so thermal cycling, mechanical mishandling during maintenance or an imperfect seat in the nest can initiate cracks or edge chips. These compromise electrode continuity and become a direct source of particles and arcing.

Seating, deposition and arcing faults

Polymer build-up in the nest, contamination on mating surfaces or a ring that is not fully seated can cause poor RF contact, localised hot spots and arc damage. Such faults degrade matching and can scar both the ring and the underlying electrode.

Installation and replacement guidance

Replacement should follow TEL-approved maintenance procedures for the specific chamber, performed by trained personnel under proper vacuum-hygiene discipline. A typical sequence is as follows:

• Vent the chamber, confirm RF power is isolated and locked out, and allow the electrode assembly to cool to a safe handling temperature.
• Remove the worn outer cell electrode ring, noting its orientation and recording accumulated RF hours for erosion tracking.
• Inspect and clean the (NEST) seat and all mating surfaces, removing polymer residue so the new ring will make full, even contact.
• Handle the new silicon ring with clean, powder-free gloves only; avoid point loading and never force it into position.
• Seat the ring squarely into the nest, verifying it lies flat, concentric and fully home with no rock or gap.
• Reassemble the electrode stack to the specified configuration and confirm correct stack height and clearances.
• Pump down, leak-check, season the chamber and run qualification wafers to confirm edge uniformity and particle performance before returning to production.

Spare parts strategy for TEL etch consumables

Outer cell electrode rings are scheduled-replacement consumables, so availability and consistency matter as much as the part itself. Sourcing through ESCT Fab Support gives fabs a dependable alternative to single-channel OEM supply:

• 2nd Source NEW parts verified to the original form, fit and function of OEM P/N 2L10-251992-11.
• High-purity silicon and controlled machining to support stable chamber matching across a tool fleet.
• A typical lead time of 4-5 weeks, supporting planned preventive-maintenance cycles and buffer stock.
• Clear ESCT part referencing (ES7099-128) for straightforward reordering and stores management.
• Competitive cost of ownership against sole-source procurement, without compromising process integrity.

Frequently asked questions

What exactly does the outer cell electrode ring do?

It is the powered silicon ring that frames the outer edge of the lower electrode (cell electrode) in a TEL 300 mm etch chamber. It extends the electrode surface beyond the wafer, shapes the plasma sheath at the wafer edge and provides an RF return path, all of which control edge etch uniformity and profile.

Is this an original OEM part?

No. This is supplied as a 2nd Source NEW, OEM-compatible part. It is manufactured to match the form, fit and function of TEL OEM P/N 2L10-251992-11 but is not an original Tokyo Electron branded component.

What material is the ring made from?

It is made from high-purity, high-resistivity silicon, the same class of material used for plasma-exposed electrode and edge consumables, chosen for clean erosion behaviour and low contamination risk.

How do I know when it needs replacing?

Replacement is normally driven by accumulated RF hours and by drift in edge uniformity, particle counts or profile metrics. Visible thinning, edge rounding, cracking or arc marks during a scheduled PM are clear indicators that the ring has reached end of life.

What is the lead time and how should I stock it?

Typical lead time is 4-5 weeks. Because the ring is a scheduled consumable, fabs usually hold buffer stock aligned to their PM frequency and the number of matched chambers in the fleet to avoid unplanned downtime.

Will it affect chamber matching?

Used correctly, no. The part is produced to consistent silicon resistivity and dimensional tolerances so it behaves repeatably from chamber to chamber. As with any electrode consumable, qualification wafers should be run after installation to confirm matching before production resumes.

Summary

The Outer Cell Electrode Ring (ST-P nest, V2; OEM P/N 2L10-251992-11; ESCT P/N ES7099-128) is a high-purity silicon consumable that sits at the perimeter of the lower cell electrode in TEL 300 mm plasma etch chambers. By extending the powered electrode, shaping the edge sheath and providing a stable RF return path, it directly governs edge etch uniformity, profile control and particle performance. It wears predictably through plasma erosion and must be replaced on schedule to protect yield and chamber matching. Supplied by ESCT Fab Support as a 2nd Source NEW part with a 4-5 week lead time, it offers a reliable, cost-effective route to keeping TEL etch tools in qualified production.

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 2L10-251992-11. 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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