3D10-250442-31
FOCUS RING,380-T4.O,E

TEL focus ring 380-T4.O (OEM P/N 3D10-250442-31), edge etch consumable for Tokyo Electron 300 mm plasma etch systems

ESCT P/N ES7099-038, second-source new focus ring for TEL 300 mm etch process chambers

The TEL Focus Ring 380-T4.O (OEM P/N 3D10-250442-31) is a circular edge consumable that surrounds the 300 mm wafer inside a Tokyo Electron plasma etch process chamber. Concentric with the electrostatic chuck, it forms the annular boundary between the wafer edge and the surrounding chamber hardware, sitting flush against the outer perimeter of the wafer so that the plasma sheath extends smoothly across the entire production surface rather than collapsing abruptly at the wafer’s edge.

In any capacitively coupled etch reactor, the wafer edge is the most difficult region to control. The discontinuity between conductive silicon and the dielectric chamber surroundings distorts the local electric field, bends ion trajectories and alters etch rate within the outermost few millimetres of the wafer. The focus ring exists to compensate for that discontinuity. By presenting a sacrificial surface at the same height and dielectric character as the wafer, it effectively extends the wafer plane outward, pushing the edge effects off the product and onto the consumable.

Because it is directly exposed to ion bombardment and reactive plasma chemistry, the focus ring is a scheduled-wear item. Its dimensional stability, surface condition and electrical character drift over thousands of RF hours, and that drift maps directly onto edge yield. This makes the 380-T4.O one of the parts that fabs replace most frequently, and one where a reliable, dimensionally faithful supply sustains wafer output.

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

Within a TEL etch chamber the focus ring performs several interlocking jobs at once, all of them aimed at making the wafer edge behave as though it were part of an infinitely large, uniform surface. Its principal functions include:

• Extending the plasma sheath uniformly beyond the wafer edge so that ion incidence angle stays vertical across the outermost dies.
• Shaping the local electric field at the wafer perimeter to suppress edge tilting, notching and critical-dimension roll-off.
• Providing a controlled RF return and impedance path at the wafer edge, helping define the boundary of the active plasma region.
• Confining the discharge over the chuck and protecting the chuck periphery and underlying hardware from direct plasma attack.
• Acting as a sacrificial wear surface that absorbs edge erosion in place of more costly chamber components and the wafer itself.
• Maintaining repeatable edge geometry from wafer to wafer so that edge etch results stay within process control limits across a consumable’s life.

Material and process performance

A focus ring only works if its material and finish match the electrical and chemical environment of the wafer it surrounds. The 380-T4.O is engineered to behave predictably under continuous plasma exposure while wearing in a uniform, well-characterised manner.

Material composition and plasma resistance

Focus rings for 300 mm etch service are produced from high-purity ring materials selected to match the wafer’s dielectric and conductive behaviour while resisting fluorine- and chlorine-based chemistries. Key material attributes include:

• High bulk purity to avoid introducing metallic or particulate contamination into the etch ambient.
• A controlled resistivity or dielectric constant chosen to give the desired edge field profile.
• Resistance to sputter erosion and chemical attack from aggressive halogen plasmas at elevated RF power.
• Predictable, slow erosion that keeps edge geometry within tolerance over a long consumable life.

Dimensional and surface precision

The geometric fidelity of the ring is as important as its chemistry. Step height relative to the wafer, inner diameter, flatness and seating surfaces are all tightly toleranced:

• Inner-diameter clearance held tight so the wafer-to-ring gap stays consistent and edge effects remain symmetric.
• Top-surface height matched to the wafer plane to keep the sheath flat across the transition.
• Flatness and parallelism controlled for even seating on the chuck periphery and uniform thermal contact.
• Surface finish specified to limit particle generation and to give a repeatable erosion signature.

Impact on tool performance and yield

Because it governs the behaviour of the wafer edge, the condition of the focus ring is felt directly in the yield of the outermost dies and in chamber stability overall. A worn, mismatched or poorly made ring shows up as:

• Edge critical-dimension drift and increasing centre-to-edge etch non-uniformity as the ring erodes.
• Tilted or distorted etch profiles on the perimeter dies, reducing usable die count per wafer.
• Particle excursions and defectivity as the ring surface degrades and sheds material.
• Shifts in RF impedance and matching that destabilise the plasma and force frequent recipe re-tuning.
• Shorter intervals between wet cleans and unplanned chamber downtime, eroding overall tool availability.

Common wear and failure modes

Erosion and step-height loss

The dominant wear mode is gradual sputter and chemical erosion of the ring’s upper surface. As the top face recedes, the step height relative to the wafer changes, the sheath at the edge bends and edge etch rate and profile drift out of specification. This is the normal end-of-life mechanism and the reason the ring is tracked against an RF-hour or wafer-count budget.

Cracking and chipping

Thermal cycling, mechanical handling during maintenance and localised hot spots can crack or chip the ring, particularly at the thin inner edge. A fractured ring loses its electrical symmetry immediately and becomes a serious particle source, so any visible crack or chip is grounds for prompt replacement.

Surface roughening and deposition build-up

Polymer and by-product films can accumulate on the ring while plasma attack simultaneously roughens its surface. The combination changes the local secondary-emission and erosion behaviour, raises defectivity and can flake during cycling, contaminating the wafer edge and triggering particle alarms.

Installation and replacement guidance

Replacing the focus ring is a routine preventive-maintenance task, but it must be done cleanly and precisely because seating and orientation directly affect edge results. A typical sequence is:

• Place the chamber in maintenance mode, vent to atmosphere and confirm RF and gas isolation per the tool’s lockout procedure.
• Open the chamber and remove the worn ring, noting its orientation and inspecting the chuck periphery and seating surfaces for residue or damage.
• Clean the seating area and verify it is free of particles, flakes and deposition before fitting the new part.
• Handle the new 380-T4.O with clean, powder-free gloves only, avoiding contact with the active surfaces to prevent contamination.
• Seat the ring concentrically on the chuck, confirming it lies flat and fully home with the correct orientation and an even wafer-to-ring gap.
• Close the chamber, pump down, leak-check and run season or conditioning cycles before returning to production.
• Reset the consumable counter and verify edge uniformity and particle performance with monitor wafers before releasing the tool.

Spare parts strategy for TEL etch consumables

Focus rings are among the highest-frequency consumables in a TEL etch bay, so securing a dependable supply is central to keeping chambers running and yield stable. Sourcing the 380-T4.O through ESCT Fab Support offers:

• A second-source new part verified to the form, fit and function of OEM P/N 3D10-250442-31.
• Clear cross-referencing under ESCT P/N ES7099-038 for straightforward reordering and inventory control.
• A competitive alternative to single-source OEM procurement, helping diversify supply and manage cost.
• A standard lead time of 4-5 weeks, supporting planned preventive-maintenance scheduling and buffer-stock policies.
• Dimensionally faithful parts that protect edge uniformity and particle performance across the consumable’s life.
• Application support focused specifically on TEL 300 mm plasma etch consumables.

Frequently asked questions

What does this focus ring actually do in the chamber?

It surrounds the 300 mm wafer and extends the plasma sheath and electric field uniformly past the wafer edge. By doing so it keeps ion trajectories vertical at the perimeter, controls edge etch uniformity and profile, and absorbs edge erosion as a sacrificial part so the wafer and chamber hardware are protected.

Is this an original OEM part?

No. This is supplied as a second-source new part, manufactured to be OEM-compatible and verified to the form, fit and function of TEL OEM P/N 3D10-250442-31. It is not an original Tokyo Electron part and is not sold as one, but it is intended as a direct functional equivalent for the same application.

How often does the focus ring need replacing?

Replacement intervals are process-specific and are governed by RF hours, wafer count and measured edge performance rather than a fixed calendar date. Fabs typically retire the ring once erosion and step-height loss begin to push edge uniformity or particle levels toward control limits.

What happens if I run a worn or cracked ring too long?

Edge critical dimensions drift, perimeter dies develop tilted or distorted profiles and yield at the wafer edge falls. A cracked or heavily eroded ring also becomes a particle source and can shift RF matching, destabilising the plasma and forcing unplanned downtime.

Are any special handling precautions required?

Yes. The ring should be handled only with clean, powder-free gloves, kept free of skin oils and particles, and seated flat and concentric in the correct orientation. Contamination or improper seating directly degrades edge uniformity and particle performance once the chamber is back in service.

What is the lead time for this part?

The standard lead time is 4-5 weeks. Because focus rings are consumed regularly, we recommend aligning orders with your preventive-maintenance schedule and holding buffer stock to avoid chamber downtime.

Summary

The TEL Focus Ring 380-T4.O (OEM P/N 3D10-250442-31, ESCT P/N ES7099-038) is a precision edge consumable for Tokyo Electron 300 mm plasma etch chambers. By extending the plasma sheath and shaping the electric field beyond the wafer edge, it preserves edge etch uniformity, controls particle performance and protects the wafer and chamber hardware as a sacrificial surface. As a high-frequency wear item it demands tight dimensional fidelity and reliable supply. Offered as a second-source new part on a 4-5 week lead time, ES7099-038 gives etch operations a dependable, cost-effective alternative for sustaining edge yield and tool availability.

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 3D10-250442-31. 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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