Oxford RIE

About

Oxford PlasmaPro 80 RIE tool in Etch Bay

Films / Materials: This is an Oxford Instruments PlasmaPro 80 reactive ion etcher (RIE) optimized for etching dielectric materials such as SiO₂, Si₃N₄, and Si, with good anisotropy and control. It is primarily used for etching dielectrics in micro- and nanofabrication processes. Hardware: Parallel-plate capacitively-coupled RF plasma system (13.56 MHz). Open-load design for fast loading/unloading of samples. No load lock; direct chamber access. Electrode/table temperature controlled at 20°C (ambient/chilled). Includes optical endpoint detection (Horiba Jobin Yvon LEM G50) for precise process stop. Gases:

• Ar (argon – physical sputtering/milling component)
• O₂ (oxygen – for ashing, oxidation, or enhancing etch rates)
• CF₄ (tetrafluoromethane – fluorine-based etching of SiO₂/Si₃N₄)
• CHF₃ (trifluoromethane – for selective SiO₂ etching, polymer sidewall passivation)
• SF₆ (sulfur hexafluoride – high-rate isotropic/fluorine etching of Si/SiO₂)

Etch Properties:

• Primarily anisotropic etching of dielectrics via ion bombardment and chemical reactions.
• Suitable for shallow to moderate depth etches (avoid deep polymer etching >1 µm due to restrictions).
• High selectivity possible depending on gas mix and power (e.g., SiO₂ over Si with CHF₃/O₂).
• Excellent process control for uniformity across up to 200 mm substrates.

Applications: Etching of dielectric layers (e.g., oxide/nitride masks, passivation removal, via openings), resist descum, surface cleaning/activation. Not for exposed metals (except Cr) or deep polymer etches; polymer may be used as a mask only.

Usage: Load sample directly (pieces to 200 mm wafers), select/load recipe, set time/power based on calibrated etch rates. Use endpoint detection for timed or auto-stop processes. Monitor particles and uniformity post-etch.

Detailed Specifications

• Model: PlasmaPro 80 reactive ion etcher
• Location: Etch Bay 1
• Substrate size: Up to 8 (200 mm) wafers (pieces/smaller possible; open loading)
• RF Power: Table RF power (max) 300 W (13.56 MHz)
• Table temperature: 20°C (chilled/controlled) / (max) 80°C
• Gases:
  • CHF₃ (max) 100 sccm
  • Ar (max) 100 sccm
  • O₂ (max) 50 sccm
  • CF₄ (max) 50 sccm
  • SF₆ (max) 100 sccm
• Features: Optical endpoint detection (Horiba Jobin Yvon LEM G50), open-load design for fast access, excellent etch uniformity and rate control

Restrictions and Materials Allowed

Restrictions	Materials Allowed
No exposed metals except Cr No deep polymer etching (> 1 µm) Polymers allowed only as masks Not intended for metal etching Avoid uncalibrated deep or high-aspect-ratio processes	SiO₂ Si₃N₄ Si Oxide masks Nitride masks Passivation removal Via openings Resist descum Surface cleaning and activation Chromium (Cr) as exposed metal

Safety & Emergency

Required PPE: Safety glasses, cleanroom gloves, bunny suit. Toxic gases used: CHF₃, SF₆, CF₄ — fluorine byproducts (HF) possible. Do not open chamber if gas alarm is active. If the tool alarms or gas cabinet shows red:

1. Press EMO (Emergency Machine Off) — red button on the front panel.
2. Evacuate Etch Bay 1 and notify staff immediately.
3. Call Nanofab staff: Chandan Ramakrishnaiah, +1 (213) 551-6726.
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.

Dry Etcher Comparison

Use this table to help choose the right etching tool for your process.

Feature	Oxford RIE	Oxford DRIE	Oxford DRIE-ALE	Oxford III-V	XeF2 Etcher
Model	PlasmaPro 80 RIE	Oxford System 100 DRIE	Oxford DRIE + ALE	PlasmaPro 100 Cobra	Custom built (Armani group)
Location	Etch Bay 1	Etch Bay 1	Etch Bay 1	Etch Bay 1	Deposition Bay 1
Substrate Size	Up to 200 mm (8")	Up to 4" clamp; 2", 3", 4", 6", 8" possible	Up to 4" clamp; 2", 3", 4", 6", 8" possible	Up to 4" clamp; 2", 3", 4", 6", 8" possible	Up to 6"
Etch Type	RIE (capacitively coupled)	DRIE / Bosch (ICP)	DRIE + Atomic Layer Etch	ICP-RIE (cryo capable)	Isotropic chemical etch
Table RF Power	300 W max	300 W max	300 W max	1500 W max	N/A
ICP Power	None (RIE only)	3000 W max	3000 W max	1500 W max	N/A
Table Temperature	20°C	20°C	-120°C to 200°C allowed (-150°C to 400°C max)	-120°C to 200°C allowed (-150°C to 400°C max)	20°C
Gases	Ar, O₂, CF₄, CHF₃, SF₆	Ar, O₂, CF₄, CHF₃, SF₆, C₄F₈	Ar, O₂, C₄F₈, SF₆, BCl₃, Cl₂, H₂, N₂O, CH₄, CF₄, CHF₃	Ar, O₂, SF₆, CH₄, H₂, Cl₂, BCl₃, SiCl₄	XeF₂ (crystal source)
Allowed Materials	Si, SiO₂, Si₃N₄, oxide/nitride masks, Cr	Si, SiO₂, SiN, Parylene, Polyimide, LiNbO₃, BCB	InP, InAs, GaN, AlGaAs, GaAs, InGaAsP, ITO, Si, SiC, MoS₂, WSe, Graphene	InP, InAs, GaN, AlGaAs, GaAs, InGaAsP, ITO, Si, SiC, MoS₂, WSe, Graphene	Si only
Disallowed	No metals except Cr; no deep polymer >1 µm	No exposed metals except Cr	No metals except Cr; no deep polymer >1 µm	No metals except Cr; no deep polymer >1 µm	None listed
Endpoint Detection	Optical (LEM G50)	Not Available	TBD	Optical (LEM G50)	Not Available
Best For	Dielectric etching, passivation removal, via openings, resist descum	Deep Si etching, high-aspect-ratio structures, Bosch process	Precise atomic-layer-level etch control	III-V semiconductors, exotic/compound materials, cryo etching	Fast isotropic Si etching, high selectivity
Status	Operational	Operational	Operational	Operational	Operational
SOP	SOP	SOP	TBD	SOP	SOP

Documentation

• SOP
• OES SOP
• Laser Endpoint SOP
• Training video
• Training required – contact lab staff (Chandan Ramakrishnaiah) Request form

Recipes & Data

• Standard Recipes: Standard Recipe
• Process Control and Calibration Data: Standard Recipe Calibration

Recipe Control Charts

• SiO2 Etch Control Chart

• SiNx Etch Control Chart

Troubleshooting

Plasma won't ignite

Check gas flows are stable, pressure is in range (10–200 mTorr), and RF matching network is tuned.

Etch rate dropped suddenly

Chamber may need conditioning. Run an O₂ clean recipe for 30 min.

Endpoint detector not triggering

Verify Horiba LEM G50 is on, lens is clean, correct wavelength is selected. See OES SOP.

Chamber pressure won't drop

Possible vacuum leak or pump issue. Stop process, notify staff.

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.