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The Shin Cooling Focus Ring 360-T4.5-29 is a consumable plasma-confinement component installed at the outer perimeter of the electrostatic chuck (ESC) in Tokyo Electron 300 mm plasma etch chambers. As a focus ring, it surrounds the production wafer and extends the plasma sheath outward beyond the wafer edge, so that the reactive ion environment seen by the outermost dies matches that experienced by the centre of the wafer. The “cooling” designation indicates a ring geometry and material stack intended to manage the thermal load delivered by ion bombardment at the wafer edge, while the dimensional code 360-T4.5-29 describes its nominal outer diameter class, a 4.5 mm thickness reference and the bore profile that registers it against the chuck and the silicon wafer it frames.
In a 300 mm etch tool, the wafer sits on the ESC at the centre of the lower electrode, and the focus ring forms a sacrificial collar immediately around it. Without this ring, the electric field would bend sharply at the wafer edge, distorting ion trajectories and starving the edge of etch species. The focus ring presents a dielectric and electrical continuation of the wafer surface, so the sheath remains flat and the ion flux stays vertical right out to the wafer’s last few millimetres. Because the ring is in the direct line of fire of the plasma, it is designed to be replaced on a defined maintenance interval rather than to last the life of the chamber.
This part matters because edge yield is disproportionately useful. The outermost ring of dies on a 300 mm wafer represents a significant fraction of total die count, and edge etch behaviour is governed almost entirely by the focus ring’s height, profile and material condition. A worn or incorrect ring directly translates into edge critical-dimension drift, tilted etch profiles and lost product at the wafer periphery.
The Shin Cooling Focus Ring 360-T4.5-29 performs several interlocking electrical, thermal and process functions at the wafer edge of a TEL etch chamber:
Focus rings of this class are produced from process-grade silicon or comparable plasma-compatible materials selected to match the chemistry of the etch and to erode in a controlled, predictable manner. Material choice and dimensional precision are the two factors that most directly determine how the ring behaves and how long it lasts.
The ring material is chosen so that its erosion products do not contaminate the wafer or alter the etch chemistry. High-purity silicon, for example, is consumed by fluorine and other reactive species in a way that is chemically benign to a silicon device wafer, which is why it is a common focus-ring material in TEL etch chambers.
The 360-T4.5-29 dimensional code reflects how tightly the ring must be toleranced. Outer diameter, thickness, inner-bore profile and the step that registers against the wafer all influence the local sheath shape and the ring’s seating on the chuck.
Because the focus ring governs the edge plasma environment, its condition feeds directly into device-level metrics measured at the wafer periphery. A fresh, in-specification ring and a worn one can produce visibly different results from the identical recipe:
The dominant wear mode is gradual erosion from continuous ion bombardment. As material is consumed, the ring’s effective height drops, the sheath sinks relative to the wafer edge, and edge etch profiles begin to tilt. This is the normal end-of-life mechanism and the reason the ring is treated as a scheduled consumable rather than a permanent part.
Repeated thermal cycling and mechanical handling can crack or chip the ring, particularly at thin sections and the inner bore. A fractured ring is a particle source and an immediate risk to wafer integrity, so any visible crack warrants replacement before the next production run.
Non-uniform plasma exposure can roughen or pit the ring surface, while contamination or debris under the ring degrades its seating, thermal contact and electrical continuity with the chuck. Both conditions produce asymmetric edge behaviour and inconsistent wafer-to-wafer results.
Focus-ring replacement is a routine preventive-maintenance task, but it must be performed cleanly and precisely because seating and concentricity directly affect process results. The following sequence reflects good practice for this class of part:
Focus rings are high-turnover consumables, so their availability and cost directly shape a fab’s maintenance economics. Sourcing them through ESCT Fab Support offers several practical advantages:
It sits around the wafer at the outer edge of the electrostatic chuck and extends the plasma sheath beyond the wafer, keeping ion incidence vertical and uniform so that edge dies etch the same as the wafer centre. It also manages edge thermal load and protects the chuck from plasma erosion.
No. This is supplied as a second-source new part, verified to match the form, fit and function of the OEM focus ring referenced by P/N 3D10-250755-21. It is not an original TEL OEM part, but is intended as a direct, compatible replacement.
Focus rings are consumables whose life depends on the chemistry, RF power and run time of the specific process. Most fabs replace them on a fixed preventive-maintenance interval or wafer count, before erosion lowers the ring enough to degrade edge critical dimension and profile.
The usual indicators are drifting edge critical-dimension measurements, tilted or bowed etch profiles at the wafer periphery, rising edge particle counts and visible thinning, roughening or cracking on inspection. Any of these signals that the ring should be changed.
The current lead time is 4-5 weeks. Because focus rings are consumed continuously, we recommend holding a planned safety stock aligned to your preventive-maintenance schedule so that a chamber is never held waiting on a ring.
Yes. After installation you should run the required conditioning or season recipe and re-check edge critical dimension and profile before returning the chamber to production, then reset the ring-life counter so the next replacement is tracked correctly.
The Shin Cooling Focus Ring 360-T4.5-29 (OEM P/N 3D10-250755-21, ESCT P/N ES7099-071) is an edge-cooled focus ring for Tokyo Electron 300 mm plasma etch chambers. Seated around the wafer on the electrostatic chuck, it shapes the plasma sheath, holds edge ion incidence vertical, manages edge thermal load and protects the chuck as a sacrificial consumable. Its height, profile and material condition determine edge critical dimension, profile angle and edge die yield, which is why it is replaced on a planned maintenance interval. Supplied as a second-source new part with a 4-5 week lead time, it offers a cost-effective, fit-verified alternative to OEM channels for fabs maintaining a TEL etch fleet.
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 3D10-250755-21. 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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