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ICP-RIE
Oxford Instruments Plasma Technology (OIPT), Yatton, Bristol, UK
$75,000 (refurb) or $200,000 (new Trion) CRITICAL ● Single most important fabrication tool in post-MPW processingRole in QLT Fabrication
The ICP-RIE is the workhorse etch tool for all post-MPW pattern transfer. It performs three distinct etch jobs:
| Job | Chemistry | Target | Etch Depth | Selectivity Req. |
|---|---|---|---|---|
| B2: SiO₂ cladding window | CHF₃ (25 sccm) / O₂ (5 sccm) / Ar (10 sccm) | Open 3.3 μm SiO₂ to expose SiN | 3.3 μm ± 0.1 μm | >10:1 SiO₂:SiN (endpoint on SiN) |
| G4: As₂S₃ patterning | CF₄ (20 sccm) / O₂ (5 sccm) | Pattern 500 nm As₂S₃ overlay | 500 nm ± 20 nm | >5:1 As₂S₃:SiO₂ (stop on ALD spacer) |
| Chamber clean | O₃ plasma or CF₄/O₂ | Remove polymer deposits | N/A | N/A |
Why ICP specifically (not parallel-plate RIE): The ICP source decouples ion density from ion energy, allowing high etch rates with low damage ● critical for preserving the sub-1 nm RMS surface roughness of the SiN waveguide core underneath the SiO₂ cladding.
Process Criticality
The ICP-RIE directly determines:
- Waveguide surface quality ● ion bombardment energy must remain below the SiN damage threshold (~200 eV) to preserve optical loss < 1 dB/cm
- Etch profile verticality ● sidewall angles > 85° required for pattern fidelity in As₂S₃ overlay structures
- Endpoint precision ● stopping within ±0.1 μm of the SiN surface in the SiO₂ cladding etch prevents waveguide damage or incomplete window opening
- Cross-contamination control ● arsenic residues from As₂S₃ etch must not contaminate subsequent oxide etch recipes
Recommended Configuration
The PlasmaPro 100 Cobra is the gold standard for R&D and small-volume ICP-RIE processing. It has the largest install base in university and startup photonics labs worldwide.
| Parameter | Specification |
|---|---|
| Manufacturer | Oxford Instruments Plasma Technology (OIPT), Yatton, UK |
| Model | PlasmaPro 100 Cobra (ICP-RIE configuration) |
| Legacy name | Plasmalab System 100 ICP380 |
| Configuration | Single chamber, ICP source + independent RIE bias |
| Wafer capacity | Up to 200 mm (8"); 100 mm standard for our application |
| ICP source | Cobra® high-density ICP; available in 65 mm, 180 mm, and 300 mm source sizes |
| ICP source power | 0–3000 W at 13.56 MHz (typical: 300–1500 W for our recipes) |
| RIE bias power | 0–600 W at 13.56 MHz (typical: 50–200 W for our recipes) |
| Pressure range | 1–100 mTorr (APC butterfly valve) |
| Temperature | -150°C to +400°C electrode (LN₂ or He backside cooling, chiller, or resistive heating) |
| Gas lines | Up to 8 MFC channels (standard: 4–6); dual gas pod option |
| Load-lock | Optional single-wafer load-lock or cluster (up to 5 modules) |
| Endpoint detection | Optical emission spectroscopy (OES) ● standard; Ocean Optics variable wavelength |
| Control | PC-based; new PTIQ intelligent software for optimized process control |
| Wafer clamping | He backside cooling; quartz clamp with continuous contact |
| Key feature | Variable height electrode accommodates substrates up to 10 mm thick |
New for 2025–2026: Oxford Instruments has released the PTIQ software platform, offering an intuitive new UI, system health monitoring, and advanced process optimization. Systems ordered in 2026 include PTIQ as standard.
| Parameter | Specification |
|---|---|
| Manufacturer | Oxford Instruments Plasma Technology (OIPT), Yatton, UK |
| Model | PlasmaPro 100 Cobra (ICP-RIE configuration) |
| Legacy name | Plasmalab System 100 ICP380 |
| Configuration | Single chamber, ICP source + independent RIE bias |
| Wafer capacity | Up to 200 mm (8"); 100 mm standard for our application |
| ICP source | Cobra® high-density ICP; available in 65 mm, 180 mm, and 300 mm source sizes |
| ICP source power | 0–3000 W at 13.56 MHz (typical: 300–1500 W for our recipes) |
| RIE bias power | 0–600 W at 13.56 MHz (typical: 50–200 W for our recipes) |
| Pressure range | 1–100 mTorr (APC butterfly valve) |
| Temperature | -150°C to +400°C electrode (LN₂ or He backside cooling, chiller, or resistive heating) |
| Gas lines | Up to 8 MFC channels (standard: 4–6); dual gas pod option |
| Load-lock | Optional single-wafer load-lock or cluster (up to 5 modules) |
| Endpoint detection | Optical emission spectroscopy (OES) ● standard; Ocean Optics variable wavelength |
| Control | PC-based; new PTIQ intelligent software for optimized process control |
| Wafer clamping | He backside cooling; quartz clamp with continuous contact |
| Key feature | Variable height electrode accommodates substrates up to 10 mm thick |
| Alternative | Pros | Cons | Approx. Used Price |
|---|---|---|---|
| Oxford PlasmaPro 80 (Plasmalab 80+) | Simpler, cheaper, same vendor | No independent ICP source ● RIE only; less process control | $40–60k used |
| SPTS (KLA) APS/Pegasus | Excellent ICP uniformity; production-grade | Expensive even used; 200 mm oriented; complex maintenance | $80–150k used |
| Plasma-Therm Pinnacle/Versaline | Good process flexibility | Less common in used market; fewer service technicians available | $60–100k used |
| Trion Minilock Phantom III ICP | Compact; load-locked; good for 100 mm | Lower power ICP (600–1250 W); limited process gas capacity | $30–50k used |
| Samco RIE-101iPH | Compact desktop; low cost | Limited power; no true ICP separation; small wafer only | $20–30k used |
| Gas | Purity | MFC Range | Primary Use | Safety Classification |
|---|---|---|---|---|
| CHF₃ | 99.99% | 0–50 sccm | SiO₂ etch (B2) | Toxic; gas cabinet required |
| CF₄ | 99.99% | 0–50 sccm | As₂S₃ etch (G4); chamber clean | Low toxicity; irritant |
| O₂ | 99.999% | 0–50 sccm | Additive for selectivity + polymer control; chamber clean | Oxidizer |
| Ar | 99.999% | 0–50 sccm | Physical sputter component; carrier gas | Inert |
| N₂ | 99.999% | House supply | Load-lock purge; system purge | Inert |
| He | 99.999% | 0–20 sccm | Backside wafer cooling (if cryo-chuck) | Inert |
Process Integration
B2: SiO₂ Cladding Window Etch
- Load photoresist-patterned wafer via load-lock (SPR-220 mask, post-develop hard-bake)
- Pump down to base pressure (<5 × 10⁻⁶ Torr)
- Strike plasma: CHF₃ 25 / O₂ 5 / Ar 10 sccm; ICP 1000 W; RIE 100 W; 10 mTorr
- Monitor OES for SiN endpoint (F radical intensity decrease when SiO₂ cleared)
- Etch time: ~33 min for 3.3 μm SiO₂ at 100 nm/min
- Stop etch; pump down; unload via load-lock
- Inspect under microscope: verify complete window opening; check resist integrity
- Proceed to resist strip (wet bench #06)
G4: As₂S₃ Patterning Etch
- Load As₂S₃-coated wafer with patterned resist mask
- Strike plasma: CF₄ 20 / O₂ 5 sccm; ICP 600 W; RIE 50 W; 5 mTorr
- Etch time: ~6 min for 500 nm As₂S₃ at 80 nm/min
- Monitor OES for endpoint (As/S emission lines decrease at SiO₂ interface)
- Over-etch 10% (~36 s) to ensure pattern completion
- Unload; inspect As₂S₃ pattern fidelity
Chamber Clean (Between Process Changes)
- Run O₂/CF₄ clean recipe: 40/20 sccm; ICP 800 W; 0 W bias; 50 mTorr; 5 min
- Run 3× if switching from As₂S₃ to SiO₂ etch (arsenic cross-contamination prevention)
- Run conditioning wafer (dummy Si) after clean before production wafer
Vendor Options & Pricing
New System Cost
| Configuration | Approximate New Price (2025–2026) |
|---|---|
| Oxford PlasmaPro 100 Cobra (basic, 4 gas, 100 mm, 65 mm source) | $350,000–$450,000 |
| Oxford PlasmaPro 100 Cobra (full, 8 gas, 200 mm, 300 mm source, cryo, PTIQ) | $500,000–$700,000 |
| Oxford PlasmaPro 100 Cobra clustered (2+ modules) | $700,000–$1,200,000 |
| SPTS Pegasus (production ICP-DRIE) | $600,000–$1,200,000 |
| Trion Minilock Phantom III ICP (new) | $180,000–$250,000 |
Note: New prices are not published. Estimates from university NSF MRI grant budgets, published equipment proposals, and industry sources. Actual pricing requires direct quote from Oxford Instruments.
Used/Refurbished Market
| Condition | Price Range | What You Get |
|---|---|---|
| "As-Is" from liquidation | $15,000–$40,000 | No testing; may need $10–30k in repairs; no warranty; buyer handles shipping |
| Tested / cosmetic refurb | $40,000–$80,000 | Pumped down; basic function verified; cleaned; 30-day warranty typical |
| Full OEM-spec refurb | $80,000–$150,000 | All seals replaced; MFCs calibrated; RF generators tested; new PC; 6–12 month warranty |
| "Like New" late-vintage | $120,000–$200,000 | Recent-build used tool; full documentation; near-new performance |
Where to Buy
| Dealer | Website | Contact | Specialization |
|---|---|---|---|
| Capovani Brothers Inc. | capovani.com | [email protected] / (518) 346-8347 | Major used semi-equipment; strong Oxford/SPTS stock |
| ClassOne Equipment | classoneequipment.com | Sales via website | Specialized Oxford, Plasma-Therm refurbishment; turnkey install + training |
| CAE Online | caeonline.com | Via website | Global aggregator; broad inventory |
| SemiStar Corp | semistarcorp.com | Via website | Refurbs including STS/SPTS and Oxford systems |
| CapEx Outsource | capexoutsource.com | Via website | Global; strong STS/Plasma-Therm inventory |
| Machinio | machinio.com | Search + RFQ | Aggregator marketplace |
| FabSurplus | fabsurplus.com | Via website | Pre-owned semiconductor tools |
Cost History & Market Dynamics
USED ICP-RIE PRICE TREND (Oxford Plasmalab 100): 2018-2019: $30-60k (pre-COVID; high used supply from decommissioned fabs) 2020-2021: $50-80k (COVID supply chain tightened used market) 2022-2023: $80-120k (semiconductor boom; used equipment in HIGH demand) 2023-2024: $70-100k (market cooling; more used inventory becoming available) 2025-2026: $60-90k (estimated; balanced supply-demand for used tools) TREND: Used ICP-RIE prices peaked in 2022-2023 during the global semiconductor equipment shortage. Prices have begun normalizing but remain 40-60% higher than pre-COVID levels. DEMAND DRIVERS: ├── Compound semiconductor (GaN, SiC) growth → high demand for ICP-DRIE ├── Photonics/MEMS startups → increasing demand for 100-150 mm class tools ├── University lab expansion → consistent demand for refurbished units └── Fab retooling → generates used supply as fabs upgrade to 300 mm+
Our Budget Recommendation
NEW PURCHASE Option (fastest delivery):
- Trion Minilock Phantom III ICP (new): $180,000–$250,000; lead time 10–14 weeks
- Contact: Trion Technology Inc., triontech.com
- Fastest new-system option at reasonable cost; compact; 100 mm; load-locked
REFURBISHED Option (best value):
- Oxford Plasmalab 100 ICP/RIE (refurb): $65,000–$85,000; lead time 4–8 weeks if in stock
- Configuration: ICP + RIE, 100 mm, 4–6 gas lines (must include CHF₃, CF₄, O₂, Ar)
- Condition: Fully refurbished with 6-month warranty
- Vendor: ClassOne Equipment or Capovani Brothers (request quotes from both)
Budget: $75,000 (refurb) or $200,000 (new Trion)
Facility Requirements
Floor Space
| Dimension | Requirement |
|---|---|
| Footprint (tool only) | 1.2 m × 0.9 m (48" × 36") |
| With pumps + chiller | 1.8 m × 1.2 m (72" × 48") |
| Service access (rear + right) | 0.8 m clearance minimum |
| Total floor requirement | 2.6 m × 2.0 m (5.2 m²) |
| Weight | 450–650 kg (depending on pump config) |
| Floor loading | 300 kg/m² minimum; concrete slab preferred |
Electrical
| Parameter | Requirement |
|---|---|
| Supply | 3-phase, 208 V / 60 Hz (North America) OR 380-415 V / 50 Hz (European-sourced) |
| Circuit breaker | 60 A, 3-phase dedicated panel |
| Wire gauge | 6 AWG minimum per leg |
| Ground | Required; isolated ground recommended for RF equipment |
| UPS | Recommended for control PC only (1 kVA) |
| Inrush current | Pumps draw 2–3× steady-state at startup |
Power Consumption
| Component | Power Draw | Duty |
|---|---|---|
| ICP RF generator | 3.0 kW max (typical 0.5–1.5 kW) | Active during etch |
| RIE bias RF generator | 0.6 kW max (typical 50–200 W) | Active during etch |
| Turbo-molecular pump | 0.3–0.5 kW | Continuous |
| Roughing pump (dry scroll/rotary) | 0.5–1.5 kW | Continuous |
| Chiller (recirculating) | 1.0–3.0 kW | Continuous |
| Control PC + electronics | 0.3–0.5 kW | Continuous |
| TOTAL SYSTEM | 5–9 kW typical; 12–15 kW peak |
Cooling Water
| Parameter | Requirement |
|---|---|
| Flow rate | 3–5 GPM |
| Temperature | 18–22°C ± 1°C |
| Pressure | 40–60 psi |
| Quality | DI water if closed-loop chiller; facility CW if building loop |
| Connection | ½" or ¾" quick-disconnect fittings |
Gas Supply
| Gas | Purity | Flow | Connection | Safety |
|---|---|---|---|---|
| CHF₃ | 99.99% | 0–50 sccm | ¼" SS, VCR | Toxic; gas cabinet + exhaust |
| CF₄ | 99.99% | 0–50 sccm | ¼" SS, VCR | Low toxicity; irritant |
| O₂ | 99.999% | 0–50 sccm | ¼" SS, VCR | Oxidizer; no oil |
| Ar | 99.999% | 0–50 sccm | ¼" SS, VCR | Inert |
| N₂ | 99.999% | House supply | ½" | Purge gas; high flow for load-lock |
| He | 99.999% | 0–20 sccm | ¼" SS, VCR | Backside wafer cooling |
Vibration, Sound, Lighting
| Parameter | Specification |
|---|---|
| Vibration sensitivity | LOW ● not vibration-sensitive during normal operation |
| Floor vibration limit | < 50 μm/s RMS (standard lab floor acceptable) |
| Combined noise | 70–80 dB(A) at 1 m (dominated by roughing pump) |
| Mitigation | Remote pump placement; acoustic enclosure reduces 15–20 dB |
| Special lighting | NOT REQUIRED (yellow safelight if loading resist-coated wafers) |
Exhaust
| Parameter | Specification |
|---|---|
| Exhaust duct | 4" (100 mm) diameter, stainless steel or PVC |
| Flow rate | 200–500 CFM |
| Scrubber | MANDATORY ● dry chemical scrubber for fluorinated species + arsenic byproducts |
| Monitoring | Inline arsine detector downstream of scrubber (for As₂S₃ etch) |
| Code compliance | Local fire marshal sign-off for toxic gas use |
Safety & Handling
Hazard Summary
| Hazard | Risk Level | Control |
|---|---|---|
| CHF₃ gas leak / toxic exposure | Critical | Gas cabinet; toxicity monitor; auto-shutoff; training |
| Arsenic byproducts from As₂S₃ etch | Critical | Scrubber with arsine detector; dedicated exhaust; PPE |
| RF radiation (13.56 MHz) | Medium | Shielded chamber; interlocks prevent operation with chamber open |
| High voltage (RF generators) | Medium | Lockout/tagout during maintenance; trained personnel only |
| Vacuum implosion | Low | Chamber designed to spec; annual pressure vessel inspection |
| Cryogenic hazard (LN₂ cooling) | Low (if equipped) | Gloves; ventilation; O₂ monitor in enclosed areas |
PPE Requirements
- Safety glasses when near operating tool
- Nitrile gloves for wafer handling
- Face shield during chamber opening / maintenance
- Hearing protection near roughing pump (> 80 dB)