1810-225148-11(U2)
CATHODE,SI,777H,6T

Silicon cathode upper electrode (OEM P/N 1810-225148-11(U2)), plasma-facing silicon electrode for TEL 300 mm etch systems

ESCT P/N ES7099-034, TEL-compatible silicon cathode, type 777H, 6T configuration

The Silicon Cathode (ESCT P/N ES7099-034, OEM P/N 1810-225148-11(U2)) is a high-purity monocrystalline or polycrystalline silicon electrode used as a plasma-facing cathode in Tokyo Electron (TEL) 300 mm capacitively coupled plasma etch chambers. Within the catalogue convention used by TEL, the “777H” designator identifies the cathode geometry and grade family, while “6T” denotes the thickness and mounting variant of the silicon disc. As a cathode component, this part forms one of the powered or grounded plasma-confining surfaces that bound the discharge region directly above or below the 300 mm wafer.

In a TEL etch chamber, the silicon cathode is far more than a structural plate. It is an electrically active, plasma-exposed surface that participates directly in the RF discharge, helps set the sheath geometry across the wafer, and acts as a controlled silicon source that conditions the chemistry of fluorocarbon and other halogen plasmas. Because it sits in the direct line of ion bombardment and radical flux, it is a consumable: it erodes predictably over its service life and is replaced on a planned interval to hold etch performance within specification.

The integrity of this electrode has an outsized influence on edge-to-edge etch uniformity, critical dimension control, defectivity and chamber matching. A cathode that has drifted out of its electrical or dimensional window will quietly degrade yield long before it fails outright, which is why fabs treat it as a tightly controlled consumable with a defined replacement strategy rather than a run-to-failure item.

Functional role of the cathode in TEL etch platforms

The silicon cathode performs several simultaneous duties in the chamber. It is at once an RF electrode, a plasma-confinement surface, a sacrificial silicon source and a thermal interface. These roles are interdependent, and the part is engineered so that all of them stay in balance across its service life.

• Couples RF power into the plasma and helps establish the electrode sheath that accelerates ions toward the wafer at the intended energy.
• Acts as a defined return or counter-electrode surface, setting the powered-to-grounded area ratio that governs self-bias and ion energy distribution.
• Serves as a sacrificial silicon source, scavenging free fluorine and other reactive species to tune fluorocarbon-rich etch and passivation chemistry.
• Confines and shapes the discharge so that radical and ion flux remain symmetric across the full 300 mm wafer surface.
• Provides a uniform, conductive thermal boundary so heat from ion bombardment is removed evenly and surface temperature stays controlled.
• Maintains a stable, low-particle surface that minimises the addition of process-killing defects to the wafer.

Material and process performance

Silicon grade, purity and resistivity

The cathode is machined from high-purity silicon selected for tightly controlled resistivity and trace-metal content. Resistivity matters because the part is an active RF electrode; the silicon must carry RF current with predictable, repeatable impedance so that power coupling and self-bias remain matched from chamber to chamber. Purity matters because the silicon is consumed into the plasma, any metallic or oxide contamination in the bulk becomes a potential wafer contaminant.

• Controlled bulk resistivity for repeatable RF coupling and consistent ion energy.
• Low trace-metal and oxygen content to limit transfer of contaminants to the wafer.
• Defined crystal grade and orientation for predictable, uniform plasma etch behaviour across the face.
• Tight flatness and parallelism so the sheath remains uniform over the 300 mm field.

Surface finish and erosion behaviour

The plasma-facing surface is finished to a specified roughness that balances initial particle performance against controlled erosion. As the cathode is sputtered and etched by ion bombardment, its surface texture, thickness and any gas-distribution features evolve. A well-engineered surface erodes evenly so that process drift is gradual and predictable, allowing the fab to schedule replacement before the part moves outside its qualified window.

• Specified surface roughness to suppress initial particle shedding after install.
• Uniform erosion characteristics that keep etch rate and uniformity drift gradual and predictable.
• Dimensional thickness (“6T” variant) matched to the chamber sheath and gap geometry.
• Clean machined features and edges that avoid arc-initiation sites and localised hot spots.

Impact on tool performance and yield

Because the cathode sits at the heart of the discharge, its condition propagates directly into device-level results. The consequences of an out-of-spec or end-of-life electrode are felt across uniformity, defectivity and tool availability.

• Centre-to-edge etch rate and critical-dimension uniformity track directly with cathode flatness and erosion state.
• Shifts in silicon resistivity or surface condition alter self-bias and ion energy, moving etch profile and selectivity.
• A worn or contaminated surface raises particle counts, driving defectivity and yield loss.
• Chamber-to-chamber matching degrades when cathode condition diverges across the fleet.
• Localised erosion or cracking can trigger arcing, scrapping wafers and forcing unplanned downtime.

Common wear and failure modes

Erosion and thinning

The dominant wear mechanism is gradual erosion and thinning from continuous ion bombardment and chemical etch. As silicon is consumed, the electrode gap and sheath geometry shift, etch rate and uniformity drift, and the fluorine-scavenging capacity falls. Once thickness approaches its minimum, the part must be replaced to keep the process inside its qualified window.

Arcing and localised damage

Surface defects, deposits, micro-cracks or non-uniform wear create high-field points where the plasma can arc. Arcing pits the silicon, ejects particles onto the wafer and can damage adjacent hardware. Arc events often accelerate once the surface roughens late in life, which is one reason planned replacement is preferred over running the cathode to failure.

Cracking and polymer build-up

Thermal cycling and mechanical stress during clamping or handling can crack brittle silicon, while fluorocarbon processes deposit polymer films that flake into particles if not periodically cleaned. Improper torque, contamination at the mounting interface or a poor thermal contact accelerates both cracking and uneven heating, shortening usable life.

Installation and replacement guidance

Cathode replacement should follow the TEL maintenance procedure for the specific chamber, performed by trained technicians under cleanroom-compatible conditions. The silicon is brittle and the electrical and thermal interfaces are sensitive to contamination, so handle it with discipline.

• Vent and isolate the chamber following the TEL lock-out procedure, confirming RF power and gas supplies are safely off.
• Remove surrounding hardware such as the upper assembly, liner or confinement rings to access the cathode, keeping fasteners ordered for reassembly.
• Release the worn cathode and inspect the mounting surface, backing structure and thermal/RF contact areas for deposits or damage.
• Clean mating surfaces per specification and handle the new silicon electrode with clean, powder-free gloves only at its edges, avoiding the plasma face.
• Seat the new cathode, verifying correct orientation and full, even contact across the interface for uniform RF return and heat transfer.
• Fasten to the specified torque pattern and value to avoid cracking the silicon and to keep electrical contact consistent.
• Reassemble surrounding hardware, pump down, run leak and RF checks, then season the chamber and re-qualify with monitor wafers before production.

Spare parts strategy for TEL etch consumables

Silicon cathodes are scheduled consumables, so a disciplined spares strategy directly protects uptime and yield. ESCT Fab Support supplies this electrode as a form, fit and function alternative to the OEM part, helping fabs control cost and lead-time risk without compromising process integrity.

• High-purity silicon and controlled dimensions verified to match the original electrode’s form, fit and function.
• Second-source availability that reduces dependence on a single supply channel and helps stabilise pricing.
• A typical lead time of 4-5 weeks, supporting planned preventive-maintenance scheduling and buffer stock.
• Cross-referencing to the OEM and ESCT part numbers for straightforward identification and ordering.
• Suitability for fleet-wide standardisation to support chamber matching across multiple etch tools.

Frequently asked questions

What does the silicon cathode actually do in the etch chamber?

It is a plasma-facing silicon electrode that couples RF power into the discharge, sets the sheath and self-bias that determine ion energy at the wafer, confines the plasma for edge-to-edge uniformity, and acts as a sacrificial silicon source that scavenges free fluorine to tune etch chemistry.

Is this an original TEL OEM part?

No. This is supplied as a new, second-source, OEM-compatible part. It is manufactured to match the original TEL component (OEM P/N 1810-225148-11(U2)) to form, fit and function, but it is not an original OEM part and is not sold as one.

Why is the cathode made from high-purity silicon?

Because the electrode is consumed into the plasma, its bulk purity becomes part of the process environment. High purity limits metallic and oxide contamination reaching the wafer, while controlled resistivity gives repeatable RF coupling and stable ion energy across the chamber.

How do I know when the cathode needs replacing?

Replacement is normally driven by accumulated RF hours or wafer count rather than waiting for failure. Indicators include drifting etch rate or uniformity, rising particle counts, increased arcing and measurable thinning of the silicon toward its minimum specified thickness.

What is the lead time for ES7099-034?

The typical lead time is 4-5 weeks. Because the cathode is a planned consumable, ordering against the preventive-maintenance schedule and keeping appropriate buffer stock is recommended to avoid unplanned tool downtime.

Will using this part affect chamber matching?

When supplied to the correct dimensions, silicon grade and surface finish, the part is intended to behave like the original electrode so that chamber-to-chamber matching is preserved. As with any consumable change, re-qualification with monitor wafers after installation is good practice before returning the tool to production.

Summary

The Silicon Cathode (ESCT P/N ES7099-034, OEM P/N 1810-225148-11(U2)) is a high-purity silicon RF electrode for TEL 300 mm plasma etch chambers, type 777H in the 6T thickness variant. It couples power into the discharge, shapes the sheath for uniform edge-to-edge etching, scavenges fluorine to control chemistry and provides a controlled thermal interface. As a scheduled consumable it erodes predictably and is replaced on a planned interval to protect uniformity, defectivity and chamber matching. ESCT Fab Support offers it as a verified second-source alternative with a 4-5 week lead time, giving fabs supply resilience and cost control without compromising process performance.

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 1810-225148-11(U2). 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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