Oxford PECVD

About

Oxford PlasmaPro System 100 PECVD tool in Deposition Bay 1

This is an Oxford Instruments PlasmaPro System 100 plasma enhanced chemical vapor deposition (PECVD) tool optimized for depositing high-quality SiO₂, Si₃N₄, or SiOₓNᵧ dielectric films with excellent uniformity and control over properties like refractive index, stress, and etch rate.

Hardware: Capacitively-coupled parallel-plate RF plasma system (13.56 MHz primary RF + low-frequency option). Gas is delivered via a showerhead over a heated electrode. Load lock for wafer transfer. No wafer clamping; fixed electrode height. Electrode diameter: 240 mm. Substrate heater up to 400°C.

Gases:

• 2% SiH₄ in N₂ (silicon precursor, diluted for safety)
• NH₃ (ammonia – nitrogen precursor for nitrides)
• N₂O (nitrous oxide – oxygen precursor for oxides)
• N₂ (purge/carrier gas)
• He (carrier/diluent)
• CF₄ (chamber cleaning/etching)

Film Properties:

• SiO₂: Deposited using 2% SiH₄/N₂ + N₂O at 350°C; typical deposition rates ~492 Å/min depending on recipe.
• Si₃N₄: Deposited using 2% SiH₄/N₂ + NH₃; denser films at higher temperatures; stress tunable via gas ratios/RF power.
• SiOₓNᵧ: Tunable oxynitrides by adjusting N₂O/NH₃ ratios.

Films suitable for passivation, masks, insulators, AR coatings, etc.

Applications: Dielectric passivation, etch masks, electrical isolation, optical coatings, capacitor dielectrics.

Usage: Select/load recipes; input deposition time based on calibrated rates. Check current rates and uniformity via process control data or test runs.

Detailed Specifications

• Model: PlasmaPro System 100/1 PECVD
• Manufacturer: OXFORD INSTRUMENSTS
• Tool Serial Number: 94-220205 (PlasmaPro System 100/1 PECVD)
• Year Build: 2015
• Location: Deposition bay 1
• Substrate size: Up to 6" wafers (pieces/smaller possible) Default: 4" wafers
• Electrode: 240 mm diameter, heated up to 400°C
• Plasma: RF Power (max) 300 W (13.56 MHz), LF Power (max) 500 W
• Features: Load lock, no clamping (fixed height)
• Base pressure: Low mTorr range (high vacuum capability)
• APC(Pressure Controller): (max) 2000 mTorr
• Gases: 2% SiH₄/N₂, NH₃, N₂O, N₂, He, CF₄
• Other: Excellent film uniformity, stress/refractive index control, in-situ cleaning possible

Restrictions and Materials Allowed

Restrictions

Materials Allowed

Dielectric deposition only not for metal deposition. No exposed gold, copper, or other soft/noble metals on samples (chamber cross-contamination). New or unlisted substrate materials require staff approval before loading. Resist/polymer substrates must tolerate process heat (heated electrode, up to 400°C) Substrate size capped at 4" wafer; only qualified recipes and gas set may be run. Avoid uncalibrated or high-stress film recipes (Consult staff).

SiO₂ Si₃N₄ SiOₓNᵧ Si, quartz, glass, sapphire substrates Approved metal underlayers (Al, Ti, Cr, Mo, W, Ta, Ni) Process gases: 2% SiH₄/N₂, NH₃, N₂O, N₂, He, CF₄

Safety & Emergency

Required PPE: Safety glasses, cleanroom gloves, bunny suit.

Hazardous gases used: SiH₄ (silane) is pyrophoric it can ignite spontaneously on contact with air. NH₃ is toxic and corrosive. N₂O is an oxidizer. Do not open the chamber or break a gas line if a gas alarm is active on the tool control software, and confirm lines are purged with N₂ before any vent or service.

If the tool alarms or gas cabinet shows red:

1. Press EMO (Emergency Machine Off) red button on the front panel.
2. Evacuate Deposition Bay 1 and notify staff immediately.
3. Call Nanofab staff: Joey Vo , +1 (213) 740-8914.
4. After hours / life-threatening: USC DPS (213) 740-4321, or 911.

Gas leak or chemical exposure: Activate bay alarm, exit cleanroom, call DPS.

Chamber vent failure: Do NOT force open. Leave tool and contact staff.

Documentation

• SOP
• Training required – contact lab staff (Joey Vo) Request form

Recipes & Data

• Standard Recipes: Standard Recipe
• Process Control and Calibration Data: Standard Recipe Calibration
• Process Control: Monitor deposition rates, uniformity (e.g. via Filmetrics F20 or ellipsometer), and particles after runs.
• Example uniformity/particle data: Perform DepCals and particle scans as per lab protocols.

Recipe Control Charts

• SiO2 Deposition Control Chart

• SiN Deposition Control Chart

Troubleshooting

Plasma won't ignite

Check gas flows are stable, chamber base pressure is in range, and the RF matching network is tuned. Confirm the load lock is fully pumped down before striking plasma.

Deposition rate has drifted from calibration

Chamber may need conditioning. Run a CF₄ plasma clean cycle, then re-verify with a DepCal coupon before resuming process runs.

Film stress or refractive index out of spec

Check the gas ratio (N₂O:SiH₄ or NH₃:SiH₄), RF/LF power split, and electrode temperature against the qualified recipe.

Poor uniformity or particles

Inspect the showerhead for clogging/residue, run a chamber clean, and verify electrode spacing hasn't drifted.(Consult Staff)

Heater not reaching setpoint

Allow a longer soak time; notify staff if the setpoint still isn't reached after 30 min.

Load lock won't pump down

Check the door seal/O-ring for wafer debris or damage; notify staff if the vacuum gauge doesn't respond.

Acknowledgment

If results from this tool appear in a publication, please acknowledge the facility:

"This work was performed in part at the USC Nanofab at the University of Southern California, Michelson Center for Convergent Bioscience."

Please also email the citation to chandanr@usc.edu so we can track facility output.