853-347146-008
ASSY,HTD PDL,FDTHRU,STPR,8"

Heated pedestal feedthrough assembly (OEM P/N 853-347146-008), 8′ heater feedthrough for LAM etch and deposition systems

ESCT Fab Support P/N ES2022-128 · LAM Research-compatible heated pedestal feedthrough assembly for 200 mm process chambers

The Heated Pedestal Feedthrough Assembly is the engineered interface that carries heater power, thermocouple signals, and ground continuity through the sealed wall of a LAM 8″ (200 mm) process chamber and into the wafer-supporting pedestal. Decoded from its abbreviated nomenclature, assembly, heated pedestal, feedthrough, with an integral stepper element and 8-inch wafer format, the part is best understood as the heated lower-electrode feedthrough that bridges atmosphere-side services and the vacuum-side heated chuck. It is a hybrid mechanical-electrical sub-assembly rather than a single discrete component, and it sits at one of the most thermally and electrically demanding boundaries in the entire tool.

In a LAM etch or deposition platform, the heated pedestal supports and warms the wafer to a precise, repeatable process temperature while simultaneously serving as the RF-coupled lower electrode. The feedthrough assembly is what makes that possible: it routes resistive heater conductors and temperature-sense wiring through a hermetic boundary without compromising the chamber vacuum, while keeping high-current heater paths electrically isolated from RF, ground, and the surrounding aluminium hardware. Where a stepper or fine-positioning element is integral, it also provides controlled vertical actuation or wafer-lift coordination referenced to the same heated assembly.

Because it spans the atmosphere-to-vacuum interface and operates under thermal cycling, plasma exposure, and mechanical load, this feedthrough is a part fabs cannot afford to have fail unexpectedly. A degraded feedthrough quietly shifts pedestal temperature, introduces thermocouple drift, or breaks vacuum integrity, each of which translates directly into scrapped wafers. Stocking a verified replacement such as ESCT P/N ES2022-128 protects both uptime and process repeatability.

Functional role of the heated pedestal feedthrough assembly in LAM 200 mm platforms

The assembly performs several tightly coupled functions at once, combining vacuum sealing, electrical isolation, thermal management and mechanical referencing into a single serviceable unit fitted to the underside of the pedestal stack:

• Delivers high-current resistive heater power through the chamber wall to the pedestal heating element while maintaining hermetic vacuum sealing.
• Carries thermocouple or RTD temperature-sense conductors so the controller can hold the wafer at its set point with minimal drift.
• Provides electrical isolation between heater conductors, RF return paths, ground, and the grounded chamber body to prevent leakage and arcing.
• Maintains a controlled, low-leak vacuum boundary using brazed or compression-sealed pins and an insulating dielectric body.
• Supplies the mechanical datum and, where a stepper element is integral, the controlled actuation reference for pedestal or lift coordination.
• Preserves ground continuity and RF integrity so the lower-electrode coupling remains stable across the 200 mm wafer.

Electrical and signal performance

Although it is a mechanical assembly, the feedthrough lives or dies by its electrical behaviour. Its pins, dielectric body and seals must hold up to combined high-temperature, high-current and RF conditions without leakage, drift or breakdown.

Power and isolation integrity

The heater conductors must carry substantial current to bring a 200 mm pedestal to temperature, so contact resistance, pin plating and conductor cross-section all matter. The dielectric body and any ceramic insulators keep those conductors isolated from ground and from one another under elevated temperature.

• Low and stable contact resistance on heater pins to minimise self-heating and voltage drop.
• High insulation resistance between conductors and ground, maintained at process temperature.
• Resistance to dielectric breakdown and tracking under combined RF and DC bias.

Signal accuracy and grounding

Temperature-sense conductors must pass through the boundary without introducing junction errors or noise that would corrupt the closed-loop temperature reading. A clean RF/ground reference keeps the lower-electrode coupling repeatable.

• Stable thermocouple/RTD continuity to avoid set-point offset and drift.
• Low-noise signal routing isolated from adjacent high-current heater paths.
• Reliable ground bonding to preserve RF return symmetry across the pedestal.

Impact on tool performance and yield

Because the feedthrough governs both how heat reaches the wafer and how accurately temperature is measured, its condition propagates directly into process results:

• Stable pedestal temperature keeps etch rate, selectivity and film properties within specification wafer to wafer.
• Accurate temperature feedback prevents controller hunting and silent set-point offset.
• A sound vacuum boundary protects base pressure and avoids virtual-leak excursions that abort runs.
• Clean RF and ground paths maintain plasma uniformity across the full 200 mm field.
• Reliable operation reduces unplanned downtime, re-qualification cycles and wafer scrap.

Common failure modes

Seal degradation and vacuum leakage

Repeated thermal cycling fatigues brazed joints, O-rings and compression seals at the feedthrough boundary. Micro-leaks raise base pressure, introduce moisture or air into the chamber, and can present as intermittent pump-down faults long before a hard failure occurs.

Electrical insulation breakdown and pin failure

Heat, contamination and RF stress degrade the dielectric body and pin insulation over time, lowering insulation resistance and inviting tracking or arcing. Heater pins may also develop elevated contact resistance, causing local overheating, inconsistent power delivery and eventual open-circuit faults.

Thermocouple drift and mechanical wear

Sense conductors and their junctions drift or open as they age, corrupting the temperature loop. Where the stepper or actuation element is integral, mechanical backlash, binding or worn references degrade positioning repeatability and can stress the surrounding seal interfaces.

Installation and replacement guidance

Replacement should follow the LAM service procedure for the specific platform and be performed by a qualified technician under proper lockout and vacuum-safe conditions. A typical sequence is:

• Isolate the tool, vent the chamber to the controlled state, and lock out heater and RF power before any disassembly.
• Label and disconnect heater leads, thermocouple/sense wiring, ground straps and any actuation connections to the feedthrough.
• Remove the pedestal hardware as required to access the feedthrough, retaining shims, fasteners and references.
• Withdraw the old assembly, then clean the mating bore and sealing surfaces, fitting new seals or O-rings as specified.
• Install ES2022-128, torque fasteners to the documented values, and verify mechanical and actuation alignment.
• Reconnect all conductors per the labelling and confirm heater isolation and thermocouple continuity with a meter.
• Pump down, leak-check the boundary, then re-qualify pedestal temperature and process performance before returning to production.

Spare parts strategy for LAM 200 mm fabs

Heated pedestal feedthroughs are exactly the kind of long-lead, high-impact component that justifies a planned spares position rather than a reactive scramble. ESCT Fab Support helps 200 mm fabs keep legacy LAM tools productive with:

• Parts verified to the original form, fit and function for OEM P/N 853-347146-008.
• Clear cross-referencing under ESCT P/N ES2022-128 for fast reordering.
• Support for ageing 200 mm platforms where OEM availability is constrained.
• Realistic lead-time visibility, this assembly carries a 9-week lead time, supporting proactive stocking decisions.
• Cost-effective sourcing without compromising vacuum, electrical or thermal integrity.

Frequently asked questions

What does this heated pedestal feedthrough assembly actually do?

It carries heater power, temperature-sense signals and ground through the sealed wall of a LAM 8″ chamber into the heated wafer pedestal, while maintaining vacuum integrity and electrical isolation. Where an actuation element is integral, it also provides the mechanical reference for that motion.

Is this an original LAM OEM part?

No. This is supplied as a new, OEM-compatible part. It is not an original LAM Research item, but it is verified to match the form, fit and function of OEM P/N 853-347146-008 so it can be fitted in place of the original assembly.

Which systems is it intended for?

It is intended for LAM 200 mm (8-inch) process platforms that use a heated lower-electrode pedestal with a chamber-wall feedthrough. Always confirm compatibility against your tool configuration and the OEM part number before ordering.

How do I know when the feedthrough needs replacing?

Typical indicators include rising base pressure or intermittent pump-down faults, pedestal temperature drift or controller hunting, falling insulation resistance, heater power inconsistency, or actuation that has become rough or imprecise.

What is the lead time?

The current lead time for this assembly is approximately 9 weeks. Because it is a long-lead, high-impact item, many fabs choose to hold one on the shelf to avoid extended downtime during an unplanned failure.

Can my own technicians install it?

Yes, provided they are qualified for LAM pedestal service and follow the OEM procedure under proper lockout and vacuum-safe practice. Correct seal replacement, torque, isolation checks and a post-install leak check and temperature re-qualification are required.

Summary

The Heated Pedestal Feedthrough Assembly (OEM P/N 853-347146-008, ESCT P/N ES2022-128) is a critical atmosphere-to-vacuum interface in LAM 200 mm process chambers, simultaneously delivering heater power, carrying temperature-sense signals, maintaining vacuum and electrical isolation, and providing mechanical reference for the heated pedestal. Its condition directly governs temperature stability, plasma uniformity and vacuum integrity, making it a part worth stocking ahead of need given its 9-week lead time. ESCT Fab Support supplies it verified to form, fit and function so fabs can keep legacy LAM tools running reliably.

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 Lam Research part number 853-347146-008. It is not an original OEM part and is not sold as one. It is not manufactured by, endorsed by, or affiliated with Lam Research, and all manufacturer names and part numbers are quoted for identification and compatibility purposes only.

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