839-031687-003
ASSY,CAPACITORS, TCP MNW 8"

LAM TCP capacitor assembly (OEM P/N 839-031687-003), RF match network capacitor bank for LAM 8′ TCP etch systems

ESCT P/N ES2022-125, capacitor assembly for the TCP match network on 200mm LAM transformer coupled plasma platforms

The LAM TCP Capacitor Assembly (OEM P/N 839-031687-003) is a pre-built bank of high-voltage, high-frequency power capacitors mounted on a common chassis, used within the radio-frequency (RF) impedance matching network of LAM Research Transformer Coupled Plasma (TCP) etch tools configured for 8″ (200mm) wafers. The designation “TCP MNW” identifies it as a match network (MNW) sub-assembly belonging to the transformer coupled plasma source, the inductive top-source architecture that LAM uses to generate dense, low-pressure plasmas for poly, metal and dielectric etch processing.

In a TCP source, RF energy is delivered from a generator through a coaxial feed into a matching network and then into the planar spiral TCP coil that sits above the dielectric window of the chamber. The match network exists to transform the highly reactive, plasma-dependent load impedance back to the 50 ohm system impedance the generator expects. The capacitor assembly is the heart of that transformation: it provides the tuned and load capacitance that, together with the network inductors and one or more variable vacuum capacitors, cancels the inductive reactance of the coil and the plasma and forces maximum forward power into the discharge with minimal reflected power.

Because this component carries large circulating RF currents at elevated voltage while sitting close to a continuously cycling plasma source, it is a known service item. When its capacitors drift, arc or fail, the match can no longer reach a stable tune point, and the symptoms propagate directly into etch rate, uniformity and tool uptime. Specifying the correct assembly therefore restores a TCP source to its qualified operating window.

Functional role of the capacitor assembly in LAM TCP platforms

Within the TCP match network the capacitor assembly performs several interlocking electrical jobs, all of which must hold their rated values across temperature and RF stress for the source to remain stable:

• Provides the fixed and tuning capacitance that, with the network inductance, resonates against the TCP coil and plasma load to achieve a 50 ohm match.
• Carries the large circulating (reactive) RF current of the matched network without overheating or shifting in value.
• Blocks DC and low-frequency components while presenting a low impedance path at the source RF frequency, protecting the generator and feed.
• Sets the tuning range of the network in concert with the motor-driven variable vacuum capacitors, defining how wide a process window the source can be tuned across.
• Maintains a low-loss, low-ESR path so that delivered power tracks set power, keeping plasma density and etch behaviour repeatable wafer to wafer.
• Presents a consolidated, pre-assembled mechanical package with defined mounting and bus geometry, preserving the stray inductance and spacing the match was characterised with.

Electrical and signal performance

Capacitance stability and dielectric integrity

RF power capacitors used in plasma match networks are typically vacuum or low-loss ceramic (porcelain or specialised RF dielectric) types selected for tight capacitance tolerance, high voltage standoff and very low dissipation factor. The assembly groups several such capacitors on a conductive bus structure, often with mica, PTFE or ceramic stand-offs that hold spacing and creepage distance. Capacitance must remain stable as the parts self-heat under circulating current; a few percent of drift can move the tune point enough to raise reflected power and force the variable capacitors toward the ends of their travel.

• High voltage standoff to survive the RF peak voltages developed across the coil-side of the match.
• Low equivalent series resistance (ESR) and low dissipation factor to minimise self-heating and RF loss.
• Tight, stable capacitance so the network resonates at the intended frequency with margin in the variable elements.
• Sound dielectric and clean, oxide-free terminations to resist partial discharge and arc tracking.

Current handling, grounding and thermal path

At match, the current circulating through these capacitors can be many times the line current drawn from the generator, so terminations, bus straps and the chassis ground reference must be low-resistance and mechanically sound. Loose or corroded joints become localised heat sources and raise contact resistance, which both wastes power and accelerates degradation. The assembly’s mounting also defines the RF return path and stray inductance; reproducing the original geometry is what allows a replacement to drop into the existing match calibration.

• High RF current rating across the operating temperature range without value shift.
• Low-resistance bus and ground connections to control loss and heating.
• Defined mounting and spacing to preserve stray inductance and the match tune map.
• A thermal path that lets the capacitors shed self-heating to the chassis and surrounding airflow.

Impact on tool performance and yield

Because the capacitor assembly sits directly in the RF power delivery chain, its condition is visible in nearly every etch metric the fab tracks. A degraded or out-of-tolerance assembly translates into measurable process and availability problems:

• Elevated reflected power and longer match settling times, reducing the net RF delivered into the plasma.
• Drifting etch rate and degraded within-wafer and wafer-to-wafer uniformity as plasma density wanders.
• Variable capacitors driven to the limits of their travel, narrowing or losing the usable process window.
• Intermittent match faults, RF trips and aborted wafers that interrupt production and depress throughput.
• Risk of arcing damage spreading to neighbouring match components, the generator output or the RF feed.
• Increased scrap and rework when subtle uniformity drift escapes detection until downstream metrology.

Common failure modes

Dielectric breakdown and arcing

Sustained high RF voltage, contamination across stand-offs, or moisture ingress can initiate partial discharge that erodes the dielectric until a capacitor flashes over. Arcing leaves carbon tracks, pits the terminations and frequently destroys the affected capacitor outright, presenting as sudden match faults or visible burn marks inside the network enclosure.

Capacitance drift and value loss

Thermal cycling and ageing of the dielectric cause gradual capacitance shift. The match compensates by repositioning the variable capacitors, so the early signature is creeping tune positions and slowly rising reflected power rather than an outright fault, a change that is easy to miss without trend monitoring of match parameters.

Connection degradation and self-heating

Repeated RF heating and mechanical vibration loosen bus joints and ground terminations. The resulting contact resistance generates hot spots, discolours hardware and can anneal or fatigue the connection until it opens intermittently, producing erratic power delivery that is difficult to diagnose because it appears load- and temperature-dependent.

Installation and replacement guidance

Replacement should be carried out by a qualified RF or equipment engineer following LAM-approved lockout and RF safety procedures. High-voltage capacitors can retain a hazardous charge, so the network must be powered down, isolated and discharged before any contact. The following sequence reflects good practice:

• Place the tool in maintenance mode, switch off and lock out the RF generator, and confirm zero forward and reflected power.
• Allow the source to cool, then open the match network enclosure and safely discharge each capacitor to chassis ground with an approved discharge tool.
• Photograph and label the existing bus straps, ground connections and any harnessing before disconnecting, so the original geometry can be reproduced exactly.
• Remove the mounting hardware and lift out the old capacitor assembly, inspecting the network for arc tracking, discolouration or collateral damage.
• Fit ES2022-125 in the original orientation, torque all electrical and mechanical connections to specification and verify clean, oxide-free contact surfaces.
• Reconnect grounds and bus work, close the enclosure, then restore power and bring up RF at low power to confirm the network tunes and reflected power is minimal.
• Run the source qualification or wet/dry clean recipe and re-verify etch rate and uniformity against the tool’s baseline before returning to production.

Spare parts strategy for LAM TCP etch systems

Match network components fail in ways that take an etch chamber offline immediately, so holding a verified capacitor assembly on the shelf is sound risk management for any fab running 200mm LAM TCP tools. ESCT Fab Support helps maintenance teams keep these legacy sources qualified and productive:

• Parts verified to the form, fit and function of OEM P/N 839-031687-003 for confident drop-in replacement.
• Clear cross-referencing under ESCT P/N ES2022-125 to simplify reordering and stores management.
• Support for ageing 8″ TCP platforms where OEM availability of match components is increasingly constrained.
• A defined four-week lead time that lets planners schedule preventive swaps around tool availability.
• Knowledgeable technical support to confirm applicability against your specific TCP source and match configuration.
• A cost-effective alternative to extended OEM lead times that helps minimise unplanned downtime.

Frequently asked questions

What does this capacitor assembly do in a LAM TCP system?

It provides the fixed and tuning capacitance inside the RF impedance matching network that feeds the transformer coupled plasma coil. Together with the network inductors and variable vacuum capacitors, it transforms the plasma load to 50 ohms so the generator delivers maximum forward power with minimal reflected power.

Is this an original LAM OEM part?

No. This item is supplied as a new, OEM-compatible part that is verified to the form, fit and function of LAM OEM P/N 839-031687-003. It is not an original LAM-branded component, and LAM Research is referenced only to identify the platform the part fits.

Which systems does it suit?

It is intended for the TCP match network on LAM transformer coupled plasma etch tools configured for 8″ (200mm) wafers. Because match network configurations vary by source generation, we recommend confirming applicability against the OEM part number and your specific tool configuration before ordering.

What is the lead time?

The current lead time is approximately four weeks. Planning a replacement against this lead time allows maintenance teams to schedule a preventive swap during planned downtime rather than reacting to an unexpected match failure.

How do I know the capacitor assembly is failing?

Typical signs include rising reflected power, longer or unstable match settling, variable capacitors drifting toward the limits of their travel, intermittent RF or match faults, and in severe cases visible arc tracking or burning inside the network enclosure. Etch rate and uniformity drift are common downstream symptoms.

Can the assembly be installed without recalibrating the match?

Because the part is verified to the original form, fit and function, it is designed to drop into the existing match geometry. However, after any RF component change you should bring up the source at low power, confirm the network tunes with minimal reflected power, and re-verify etch rate and uniformity against the tool baseline before returning to production.

Summary

The LAM TCP Capacitor Assembly (OEM P/N 839-031687-003, ESCT P/N ES2022-125) is a pre-built bank of high-voltage RF capacitors at the core of the impedance matching network on 8″ (200mm) LAM transformer coupled plasma etch tools. By holding stable, low-loss capacitance under heavy circulating current, it lets the match transform the plasma load to 50 ohms and deliver clean, repeatable RF power into the TCP coil. When it drifts, arcs or develops loose connections, the result is reflected power, process drift and downtime, making a verified, shelf-ready replacement a useful safeguard for fabs running these legacy platforms.

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 839-031687-003. 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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