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The Focus Ring J302-303 (TEL OEM P/N 3D10-250281-11, ESCT P/N ES7099-074) is a precision-machined annular consumable that surrounds the 300 mm wafer inside a Tokyo Electron plasma etch chamber. Mounted concentrically around the perimeter of the electrostatic chuck, the focus ring sits immediately outboard of the wafer edge and forms part of the continuous surface that the plasma sheath sees during processing. Its job is to make the wafer behave, electrically and physically, as though it were larger than it actually is, so that the etch behaviour at the extreme edge of the wafer matches the behaviour at the centre.
The dimensional codes embedded in the part name (the J302-303 family designator, together with nominal ring dimensions in the region of an 8.3 mm radial section and a 298.2 mm bore class) describe a ring sized to the 300 mm pedestal and tuned to a specific chamber and process. Because the focus ring is sacrificial, it is eroded by ion bombardment exactly as the wafer would be, it is one of the most frequently replaced wetted parts in any TEL etch fleet, and its condition has a direct, measurable bearing on edge yield.
As a fab-floor consumable, the focus ring is unglamorous but disproportionately important: a few tenths of a millimetre of erosion, or a small change in resistivity, can shift the edge etch rate and the ion incidence angle enough to push the outer ring of dies outside specification. Maintaining a reliable, dimensionally faithful supply of this part is therefore central to keeping a 300 mm etch tool inside its qualified process window.
The focus ring extends the RF and plasma environment beyond the physical edge of the wafer, “focusing” the ion flux so that the sheath remains flat and vertical right out to the wafer perimeter. In doing so it governs how the last few millimetres of every wafer are etched. Its principal functions are:
Focus rings for TEL etch chambers are produced from high-purity etch-grade materials chosen to erode predictably while contributing negligible contamination. The dominant choices are single-crystal or polycrystalline silicon, silicon carbide (SiC), and in some applications quartz, each selected to match the chemistry of the process running in that chamber.
Because the ring is consumed in the same plasma that etches the wafer, its purity directly governs the particle and metals budget of the process. Erosion must be uniform and slow, with the material wearing in a controlled, repeatable manner so that the ring’s profile change can be predicted and compensated by the tool.
Edge performance is acutely sensitive to ring geometry. The inner diameter, radial width, step height and flatness must hold tight tolerances so that the wafer-to-ring gap and the relative surface heights reproduce the qualified sheath geometry from chamber to chamber.
Few consumables have as direct a line to edge yield as the focus ring. As it erodes, the sheath geometry at the wafer edge drifts, and the consequences propagate through the outermost dies of every wafer processed:
The dominant wear mode is gradual erosion by ion bombardment. The ring thins over its service life, lowering its top surface relative to the wafer and progressively changing the local sheath shape. Once thickness falls below the process limit, edge uniformity drifts out of specification and the ring must be replaced, this is normal end-of-life rather than a defect.
Thermal cycling, mechanical handling and clamping stress can initiate cracks in brittle silicon or SiC rings. A cracked ring is an immediate particle source and can fail catastrophically during a cycle, risking wafer scrap and contamination of the chamber interior.
Polymer and by-product deposits can accumulate on the ring surface, while plasma attack roughens the exposed face. Both raise the particle adder count and can subtly alter the local electrical and thermal coupling, contributing to defect excursions before the ring reaches its erosion limit.
Replacing a focus ring is a routine preventive-maintenance task, but because the ring defines edge sheath geometry it must be handled cleanly and seated precisely. The following sequence reflects good practice; always defer to your site’s TEL maintenance procedure and safety rules.
Because the focus ring is a high-turnover sacrificial part, keeping qualified stock on the shelf avoids edge-yield drift and tool idle time. ESCT Fab Support supplies the ES7099-074 focus ring as a cost-effective, form-fit-and-function alternative to the OEM part, with the following advantages:
It surrounds the 300 mm wafer on the electrostatic chuck and extends the plasma sheath beyond the wafer edge, keeping ion trajectories vertical at the perimeter. This makes the edge etch behaviour match the centre, preserving within-wafer uniformity and edge die yield.
No. This is a second-source, new component supplied by ESCT Fab Support, not an original Tokyo Electron part. It is manufactured and verified to the form, fit and function of OEM P/N 3D10-250281-11 so it can be used as a direct replacement, but it is not OEM-branded hardware.
It depends on chemistry, power and RF-hours, but the focus ring is a sacrificial consumable that erodes with use. Most fabs replace it on a defined RF-hour or thickness limit during scheduled preventive maintenance, well before edge uniformity drifts out of specification.
As the ring thins, the sheath bends at the edge and ion incidence skews, causing edge CD tilt, profile errors and loss of uniformity in the outer dies. A cracked or roughened ring also adds particles, so running past limit risks both yield loss and contamination.
Focus rings for TEL etch chambers are typically high-purity silicon or silicon carbide, with quartz used in some applications. The material is chosen to match the chamber chemistry, erode predictably and keep contamination to a minimum. The ES7099-074 is supplied in the etch-grade material appropriate to this part’s application.
The standard lead time is 4–5 weeks. Because focus rings are consumed continuously, we recommend holding buffer stock and ordering against your planned preventive-maintenance schedule to avoid edge-yield risk and tool downtime.
The Focus Ring J302-303 (TEL OEM P/N 3D10-250281-11, ESCT P/N ES7099-074) is a sacrificial edge-uniformity consumable for Tokyo Electron 300 mm plasma etch chambers. By extending the plasma sheath beyond the wafer and holding ion trajectories vertical at the perimeter, it governs edge etch rate, critical-dimension control and particle performance for every wafer processed. Supplied as a second-source new part verified to OEM form, fit and function, with a 4–5 week lead time, the ES7099-074 lets fabs maintain qualified edge yield and a solid consumable supply without sole reliance on the OEM channel.
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 3D10-250281-11. 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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