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The TEL focus ring identified by OEM part number 2L10-251728-11 is an annular plasma-confinement consumable that seats around the perimeter of the electrostatic chuck in Tokyo Electron 300 mm plasma etch process chambers. Catalogued raw as “RING, FOCUS LAB 360-320-5-400H”, it is the component that extends the wafer plane outward beyond the silicon edge, so that the plasma sheath and the ion trajectories above the outermost dies behave as though the wafer continued. Without it, the electric field would curl downward at the wafer edge and the last few millimetres of usable area would etch at the wrong rate and the wrong angle.
In a TEL etch chamber the focus ring sits concentrically on the cathode assembly, surrounding the wafer and bridging the gap between the chucked wafer surface and the surrounding edge or cover rings. It is directly exposed to the bulk plasma, to energetic ion bombardment and to the reactive fluorocarbon, oxygen and halogen chemistries used for oxide, nitride, polysilicon and metal-stack etching. Because it shares the RF environment of the wafer, its dimensions, material and degree of erosion have a first-order effect on how the plasma terminates at the wafer edge.
As a sacrificial part, the focus ring is intended to wear so the wafer does not. It absorbs ion flux and erodes over hundreds of RF hours, gradually changing the local sheath geometry until edge results drift outside specification and the ring must be replaced. Understanding how it functions, how it degrades and how to replace it cleanly is central to maintaining edge yield in any high-volume TEL etch fleet.
The focus ring performs several interrelated electrical and plasma-shaping duties at the wafer edge. Each is a direct consequence of where it sits and what it is made from:
A focus ring is only as good as the material it is cut from and the dimensional precision to which it is finished. Both determine how it couples to the plasma and how predictably it ages.
TEL focus rings are produced from carefully chosen materials (commonly high-purity silicon, silicon carbide or quartz depending on chamber and recipe) selected so the ring’s electrical conductivity and erosion behaviour match the process. The material must withstand sustained ion bombardment and aggressive fluorocarbon and halogen chemistries while contributing as little particulate and metallic contamination as possible. High purity matters because anything sputtered from the ring lands within millimetres of product silicon.
The inner diameter, outer diameter, height step and flatness of the ring are tightly toleranced because they define the standoff between wafer edge and ring surface. A ring that sits even fractions of a millimetre too high or too low shifts the sheath profile and degrades edge uniformity. Concentric seating and a clean, repeatable contact to the chuck are equally important for stable RF coupling.
Because the focus ring shapes the plasma exactly where the most peripheral and most yield-sensitive dies sit, its condition translates almost directly into edge-die yield and process stability:
A focus ring is a wear part, so the question is rarely whether it will degrade but how and how quickly. The dominant mechanisms are erosion, mechanical damage and contamination.
Continuous ion bombardment slowly sputters material from the ring surface, reducing its height and rounding its edges. As the ring thins, the sheath at the wafer edge drops and tilts, pushing edge critical dimension and profile angle out of specification. This is the normal end-of-life mechanism and is why erosion is tracked against RF hours so the ring can be swapped before it costs yield.
Silicon, silicon carbide and quartz rings are brittle and can crack or chip from thermal-cycling stress, mishandling during a chamber preventive-maintenance event, or arcing. A fractured ring not only loses its plasma-shaping function but immediately becomes a generator of killer particles, so any visible crack or chip warrants immediate replacement.
Fluorocarbon recipes deposit polymer and etch by-products on the ring. Excess build-up flakes, shifts local coupling and seeds defects, while contact-surface contamination disturbs the RF return path. Roughened or discoloured surfaces, flaking deposits and unstable edge readings are all signals that the ring is no longer providing a clean, repeatable boundary.
Focus-ring replacement is a routine but precision PM task. The following sequence reflects good practice for TEL 300 mm chambers; always defer to your site’s qualified maintenance procedure and ESD and handling controls.
Focus rings are high-turnover consumables, so a dependable second-source supply protects both budget and uptime. ESCT Fab Support supplies this ring (ES7099-093) as a second-source new part built to the form, fit and function of the original:
It surrounds the wafer on the electrostatic chuck and extends the plasma sheath past the silicon edge, keeping ion bombardment vertical and edge etch results uniform. It also confines the plasma and protects the chuck, wearing sacrificially so the wafer and hardware below do not.
No. This is a second-source new part, manufactured and supplied to match the form, fit and function of TEL OEM part number 2L10-251728-11. It is not an original Tokyo Electron OEM component and is not sold as one, but it is a new part intended as a compatible alternative.
Replacement intervals depend on recipe aggressiveness, RF power and run time, so they are best tracked in RF hours rather than calendar time. Most fabs set an erosion-based limit and swap the ring once edge uniformity or particle data begins to drift, or sooner if cracking or chipping is found.
An over-eroded ring lowers and tilts the edge sheath, degrading edge critical dimension, profile angle and within-wafer uniformity, and can lose edge dies entirely. A cracked or flaking ring additionally seeds particles, risking defects across the whole wafer and unplanned chamber downtime.
TEL focus rings are made from plasma-resistant materials such as high-purity silicon, silicon carbide or quartz, chosen to match the chamber and recipe. The material sets the ring’s electrical coupling and erosion rate, and high purity keeps contamination away from nearby product silicon.
This focus ring (ESCT P/N ES7099-093) is currently quoted on a 4 to 5 week lead time. Planning replacements around this window and holding appropriate safety stock lets fabs schedule PM events without risking an extended tool-down condition.
The TEL focus ring under OEM part number 2L10-251728-11 (ESCT P/N ES7099-093) is a precision edge-confinement consumable that shapes the plasma sheath, steers ion bombardment and protects the chuck at the wafer perimeter in Tokyo Electron 300 mm etch chambers. Its material, dimensional accuracy and state of erosion determine edge critical dimension, profile control, particle performance and chamber matching. Treated as the wear part it is, tracked against RF hours, handled carefully and replaced before it drifts out of specification, it keeps edge-die yield stable. Supplied as a second-source new part by ESCT Fab Support, it offers a cost-effective, lead-time-predictable alternative for keeping TEL etch fleets in 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 2L10-251728-11. 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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