Used Cryo Etch Equipment Buying Guide 2026: Oxford, Trion, and Plasma-Therm

Let me start with a story I saw in a university cleanroom last fall. A group bought a used Trion Orion cryo etcher for $125K. It looked good on paper, and the seller had done a basic clean. But within a few months, they started getting edge-notch issues. Uniformity was off on their 4-inch wafers. Took them six weeks to trace the problem to the cryo stage. Turns out the previous user had run an organic etch process with a fluorinated additive. That gunk had seeped into the cryo stage’s vacuum-sealed chamber, clogging the thermal conductive paths. Once they opened it up, it was a mess. Rebuilding the stage alone cost them $27K. That’s not the kind of expense you budget for in a grad student’s equipment run.

This is exactly why you need to know what you're dealing with when buying used cryogenic etch systems. Let’s break it down.

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The Dollar Stakes: Contamination = Waste

Cryo etching works because it cools the wafer to -100°C or lower, reducing polymer redeposition during the Bosch process. But that cold stage is not just a piece of metal. It’s a vacuum-sealed, thermally conductive system with cryo lines, sensors, and a heat exchanger. If that’s not clean, you won’t get consistent etch profiles. You’ll see bad uniformity, edge notching, and ultimately, bad wafers. You might not even connect the symptoms to the cryo stage until you’ve burned through a few process runs.

The cost of a rebuild? $15K to $35K, depending on the model. And if the stage failed due to process contamination? That’s on you. The seller might not even know.

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Oxford Cobra vs Trion Orion vs Plasma-Therm: The Real Differences

Let’s look at the main players in the used market for cryo DRIE.

Oxford Instruments Cobra (Cobra-3500)

• Used price range: $90K to $130K
• Key spec: Up to 150mm wafers, 60:1 aspect ratio
• Pros: Modular, good for R&D, simple interface
• Cons: Older model; some versions use LN2 without active regulation. Be careful with pre-2017 builds.

Trion Orion (Orion 200/400)

• Used price range: $140K to $220K
• Key spec: Up to 200mm wafers, 100:1 aspect ratio
• Pros: Good vacuum system, better LN2 control than Oxford
• Cons: More complex, higher maintenance. Cold stage rebuilds common in the second-hand market.

Plasma-Therm (Unaxis) Cryo Etch Systems

• Used price range: $200K to $280K
• Key spec: Up to 300mm, 200:1+ aspect ratio
• Pros: Heavy-duty, industrial-grade, used in production fabs
• Cons: Heavier LN2 consumption, more vibration-sensitive. Needs cleanroom with dedicated vacuum and LN2 lines.

Choose based on your wafer size and process complexity. If you’re doing 200mm or 300mm work, the Plasma-Therm is your only option in this class. But if you’re in a university or R&D setting, the Oxford Cobra is the most cost-effective.

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The Cold Stage Is the Weak Point

No matter the model, the cryo stage is the most fragile and expensive part of the system. It uses liquid nitrogen to cool the wafer, and over time, that stage can develop microcracks from thermal cycling. Look for signs of:

• Unexplained etch profile shifts
• Inconsistent wafer temperatures during process
• LN2 consumption that’s higher than spec

If you’re buying a system with more than 3,000 process hours, ask the seller to provide a stage rebuild history. If they don’t have one, don’t buy.

A good rebuild shop can do a full cold stage service — cleaning, resurfacing, and sensor recal — for $22K to $35K. Factor that into your cost of ownership.

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Bosch vs Cryo: Make Sure You Need Cryo

Cryo etching is not always better. The Bosch process, used in standard DRIE etchers, can get you up to 60:1 aspect ratios with high etch rates. Cryo pushes that to 100:1+ by reducing redeposition.

But ask: Do you really need that? If you’re doing MEMS sensors or microfluidics, maybe not. If you’re in photonic structures or RF MEMS, then yes.

Also, consider etch rate. Cryo slows things down. You might trade speed for uniformity. Be sure you're solving the right problem.

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Site Requirements: LN2, Vacuum, Vibration

Cryo etching is more demanding in setup than regular DRIE.

• Liquid nitrogen supply: You need a dedicated LN2 line, not just a dewar. Check the flow rate per process hour.
• Vacuum pump isolation: The cryo system’s vacuum pump must be isolated from other tools to prevent cross-contamination.
• Vibration control: Plasma-Therm and Unaxis systems are sensitive to floor vibrations. Use anti-vibe mounts or dedicated concrete slabs.

Neglecting any of these will lead to a long list of service calls and unhappy operators.

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5 FAQs You’ll Google Before Buying Used Cryo Etch

1. "Used Oxford cryo etch cost 2026"
Answer: $90K to $130K used, depending on model and process hours. New is $300K+.

2. "Trion Orion cryo stage rebuild cost"
Answer: $20K to $35K, depending on damage level.

3. "Cryo DRIE vs Bosch etch which is better"
Answer: Cryo gives better uniformity and higher aspect ratios but slower etch rate. Bosch is faster and cheaper.

4. "Plasma-Therm cryo etch LN2 usage"
Answer: 1.5 to 2 liters per process hour. Ensure you have a reliable LN2 supply system.

5. "Cryogenic etch system vibration requirements"
Answer: Systems like Plasma-Therm need anti-vibration mounts and isolated power.

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5 Action Steps Before You Buy a Used Cryo Etch System

1. Verify cold stage history. Ask for rebuild logs and process history.
2. Check LN2 infrastructure. Don’t assume it’s there.
3. Test under real conditions. Run a dummy process and measure wafer temperature.
4. Inspect vacuum pump. Look for oil contamination or pressure instability.
5. Factor in rebuild costs. Add $20K–$35K to your budget for possible stage service.

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Related Reading

• Used ICP Etch Guide
• Used Semiconductor Inspection Checklist

Buying used cryo etch systems is high-stakes. One misstep with the cold stage can cost you tens of thousands and weeks of lost time. Do the homework. Call us with the serial number. We see these systems every week and can help you avoid the next six-week diagnostic nightmare.