2L10-252647-11
RING,FOCUS 318-T5.5G50L LAB

Focus ring 318-T5.5G50L (OEM P/N 2L10-252647-11), edge-etch focus ring for TEL 300 mm plasma etch systems

ESCT P/N ES7099-200, 2nd source NEW focus ring for Tokyo Electron 300 mm etch process chambers

The 318-T5.5G50L focus ring is a consumable plasma-confinement component fitted to the electrostatic chuck (ESC) assembly inside Tokyo Electron (TEL) 300 mm plasma etch chambers. It is the annular part that surrounds the 300 mm wafer at the cathode periphery, sitting flush against the outer edge of the wafer and the chuck. Its job is to extend the plasma sheath and electrical environment of the wafer surface out past the silicon edge, so that the outermost dies see the same field conditions as the centre of the wafer.

Because it occupies the position where the wafer edge meets the chamber hardware, the focus ring directly governs edge etch rate, edge profile angle and across-wafer uniformity. It is exposed to continuous ion bombardment and reactive plasma chemistry, which means it is a wear part with a defined service life rather than a permanent fixture. As the ring erodes, the local sheath geometry shifts and edge results drift, which is why this component is replaced on a planned interval as part of preventive maintenance.

ESCT Fab Support supplies this focus ring under part number ES7099-200 as a form-, fit- and function-matched alternative to the OEM consumable, allowing fabs to maintain edge yield and chamber availability without sole-source dependence on the original equipment manufacturer.

Functional role of the focus ring in TEL 300 mm etch platforms

In a TEL 300 mm capacitively coupled etch chamber, the focus ring is an active part of the RF and plasma environment, not merely a mechanical spacer. It conditions the field at the wafer edge and protects the chuck hardware beneath it. Its principal functions include:

• Extending the plasma sheath radially outward so the wafer-edge dies experience the same vertical ion trajectories as the wafer centre.
• Maintaining a uniform, near-vertical etch profile at the wafer edge by preventing the sheath from bending inward over the last few millimetres of silicon.
• Providing a controlled, sacrificial surface that takes ion bombardment in place of the chuck and chamber hardware.
• Defining the electrical termination of the wafer plane, influencing the local RF return path and impedance at the cathode edge.
• Shielding the outer edge of the electrostatic chuck and the underlying ceramic from direct plasma attack and deposition.
• Setting a repeatable physical reference height around the wafer so that edge process results stay consistent from chamber to chamber.

Material and process performance

Material behaviour under plasma exposure

Focus rings for silicon and dielectric etch are typically produced from high-purity silicon or, for some chemistries, silicon carbide or quartz, selected so the ring erodes predictably and does not introduce metallic or particulate contamination onto the wafer. The “318-T5.5G50L LAB” designation reflects the OEM dimensional and grade specification for this ring family. Material choice is critical because the ring is consumed in the same plasma that etches the wafer, so it must be chemically compatible with the process.

• High-purity material grade to minimise metallic contamination of edge dies.
• Controlled erosion characteristics so sheath geometry changes slowly and predictably over the service life.
• Chemical compatibility with fluorine- and oxygen-based etch chemistries used in TEL chambers.
• Thermal stability across the chuck temperature range so the ring does not crack or distort during cycling.

Dimensional and surface accuracy

The performance of a focus ring depends on tight control of its inner diameter, outer diameter, step height and flatness. A ring that is even slightly out of tolerance will alter the gap between the wafer edge and the ring, shifting the sheath and degrading edge uniformity. Surface finish and parallelism matter because they determine how cleanly the ring seats against the chuck and how the wafer edge couples to it.

• Inner and outer diameters held to OEM tolerance for correct wafer-edge clearance.
• Step height controlled to set the correct sheath transition at the wafer edge.
• Flatness and parallelism for even seating and consistent RF coupling.
• Specified surface finish to limit particle generation and arcing risk.

Impact on tool performance and yield

Because the focus ring controls the last few millimetres of the wafer, its condition has a disproportionate effect on edge yield. As the ring wears, the consequences propagate directly into device results and chamber economics:

• Edge etch rate drifts as the eroding ring lowers the sheath, tilting the profile and changing critical dimensions on outer dies.
• Across-wafer uniformity widens, reducing the number of good dies in the outer ring of the wafer.
• Particle counts rise as the ring surface roughens or flakes, threatening defect-density specifications.
• Chamber-to-chamber matching degrades when rings of different ages are in service, complicating process control.
• Unplanned wear can force unscheduled wet-clean or PM events, cutting tool availability and throughput.

Common wear and failure modes

Progressive erosion

The dominant failure mode is steady physical and chemical erosion from ion bombardment. The ring thins over thousands of RF hours, lowering its top surface relative to the wafer and gradually shifting the edge sheath. This is expected wear and is the primary driver of the planned replacement interval.

Cracking and chipping

Thermal cycling, mechanical handling and localised arcing can crack or chip the ring, particularly at the inner edge. A cracked ring sheds particles onto the wafer edge and can disturb the field locally, so any visible fracture is cause for immediate replacement rather than continued use.

Deposition build-up and surface roughening

Polymer and by-product films can accumulate on the ring surface, while ion impact roughens it over time. Both effects change the ring’s electrical and physical interaction with the plasma and become a source of flaking particles, contributing to defect excursions if the ring is left in service past its limit.

Installation and replacement guidance

Focus-ring replacement is a routine but precision PM task. Always follow the documented TEL procedure for the specific chamber and observe cleanroom and ESD discipline throughout. A typical sequence is:

• Vent the chamber and confirm it is at a safe temperature and that all RF and gas sources are isolated and locked out.
• Open the chamber and inspect the worn ring in place, noting its orientation and seating before removal.
• Remove the old ring using clean, non-marking tools and inspect the exposed chuck surface for residue or damage.
• Clean the seating area per the PM procedure so the new ring beds flat with no trapped particles.
• Fit the new ES7099-200 ring in the correct orientation using powder-free gloves, seating it evenly without forcing.
• Close the chamber, pump down, leak-check and complete the required season or conditioning recipe.
• Verify edge uniformity and particle performance on a qualification wafer, and log the ring change against the RF-hour counter.

Spare parts strategy for TEL etch consumables

Focus rings are high-frequency consumables, so a reliable second-source supply protects both yield and budget. Sourcing this ring through ESCT Fab Support gives fabs a practical alternative to single-source OEM purchasing:

• New, second-source parts verified to the OEM form, fit and function for ES7099-200 / 2L10-252647-11.
• Competitive pricing on a recurring consumable, reducing the lifetime cost of edge-ring maintenance.
• A planned lead time of 4-5 weeks that supports scheduled PM and buffer-stock planning.
• Reduced sole-source risk and improved resilience against OEM supply disruption.
• Cross-referencing by both ESCT and OEM part numbers to simplify procurement and stores management.

Frequently asked questions

What does this focus ring do in a TEL etch chamber?

It surrounds the 300 mm wafer at the chuck edge and extends the plasma sheath outward so the wafer-edge dies etch with the same profile and rate as the centre, while also protecting the chuck from plasma attack.

Is this an original OEM part?

No. ES7099-200 is supplied as a new, second-source part that is verified to match the OEM component (2L10-252647-11) in form, fit and function. It is not an original Tokyo Electron OEM part and is not sold as one.

How often should the focus ring be replaced?

Replacement is driven by accumulated RF hours and observed edge performance rather than a fixed calendar date. Most fabs replace the ring at a defined wear limit set during process qualification, before edge uniformity or particle counts drift out of specification.

What happens if a worn ring is left in service too long?

An over-eroded ring lowers the edge sheath, tilting the etch profile and shifting critical dimensions on outer dies. It can also begin shedding particles, causing defect excursions and loss of edge yield.

What is the lead time for this part?

The standard lead time is 4-5 weeks. Because focus rings are recurring consumables, we recommend holding buffer stock aligned to your PM schedule so a ring is always available at the planned change point.

How do I confirm this ring fits my chamber?

Match by the OEM part number 2L10-252647-11 and the ESCT reference ES7099-200, and confirm the chamber configuration with our team. Quoting both numbers when ordering gets the correct ring grade and dimensions supplied.

Summary

The 318-T5.5G50L focus ring (OEM P/N 2L10-252647-11, ESCT P/N ES7099-200) is a critical edge-confinement consumable for Tokyo Electron 300 mm plasma etch chambers. By extending the plasma sheath beyond the wafer edge and shielding the electrostatic chuck, it governs edge etch uniformity, profile control and particle performance. As a planned wear part, it must be replaced before erosion degrades yield. ESCT Fab Support offers this ring as a new, second-source alternative verified to OEM form, fit and function, with a 4-5 week lead time to support reliable preventive-maintenance planning.

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 2L10-252647-11. 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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