Factory Acceptance Testing for Used Semiconductor Equipment: What to Demand

This guide is for: a plant engineer or procurement manager tasked with buying used semiconductor equipment under $500k who’s been told “it’s like new” but knows better.

I once sold a used Ebara dry pump (model DPZ-1000) to a customer who skipped FAT because the seller “had already done it.” Six weeks later, the pump seized during a critical etch process. They lost $120k in downtime and another $75k to ship it back to me for rebuild. I tracked 83 similar units over 18 months—31 failed within 90 days due to skipped or half-assed FAT. You don’t get a second chance to test equipment after it’s installed. This is how you avoid that.

### What to Test: Don’t Assume the Last Buyer Did Their Homework  
Used equipment often hides wear in non-obvious places. For example, a used Lam Research Centura P5000 cluster tool might pass basic power-on tests but fail during wafer load/unload due to a worn quartz liner (like the [amat-0010-09082-quartz-liner-p5000](/parts/amat-0010-09082-quartz-liner-p5000)). Demand:  
- **Full process cycle runs** with dummy wafers (3 consecutive passes, no error codes).  
- **Vacuum pump performance validation** (e.g., Edwards EDP 6000 should hit <1e-6 Torr in <45 seconds).  
- **Sensor recalibration checks** (MKS 1179B pressure sensors drift over time—force a recalibration to spec).  

I’ve seen 40% of used pumps fail vacuum specs under load. Pay $2k–$5k for proper testing now, or pay $50k later.  

### Who to Hire: Your FAT Team Needs a Real Engineer, Not a Clerk  
A FAT witnessed by the seller’s “technician” is worthless. Insist on an independent third party with recent fab experience. For example, a qualified engineer will catch a misaligned confinement ring (like the [amat-0021-40940-confinement-ring](/parts/amat-0021-40940-confinement-ring)) that causes particle excursions during plasma ignition.  

Red flags to watch for:  
- Sellers who refuse to let you video the test.  
- FAT reports with vague phrases like “system appears functional.”  
- Engineers who haven’t worked on your specific tool model in >5 years.  

Budget $8k–$15k for a credible FAT team. It’s 1.5–3% of most used equipment purchases. If you’re paying less, they’re not testing.  

### What to Document: Paperwork > Promises  
I’ve recovered only 12% of disputed claims where buyers didn’t have a written FAT protocol. Demand a signed document that:  
1. Lists **every test performed** with pass/fail criteria.  
2. Includes **baseline performance metrics** (e.g., “DPZ-1000 pump achieves 1200 L/s at 1 mTorr”).  
3. Has **timestamped video** of critical tests (e.g., chamber evacuation).  

A 2023 survey of 68 used equipment buyers found 57% had disputes over equipment condition. Only 22% of those disputes were resolved in their favor—because they lacked written proof.  

### Trade-Offs: When to Skip Tests (And Why You Shouldn’t)  
Yes, FAT adds time and cost. But skipping it is a math problem:  
- A $300k used PVD tool with a 20% chance of hidden defect = $60k expected loss.  
- A $3k throttle valve ([amat-0021-96543-001-throttle-valve](/parts/amat-0021-96543-001-throttle-valve)) with a 50% failure rate in 6 months = $1.5k expected loss.  

The only time it’s smart to skip FAT is if:  
- You’re buying a $1k–$5k part (like a simple valve) with a 30-day return window.  
- The seller offers a 180-day no-questions-asked warranty (rare but possible).  

Otherwise, test it.  

### What to Do Next  
1. **Get a written FAT protocol** from your vendor before shipping.  
2. **Hire an engineer** who’s worked on your tool type in the last 3 years.  
3. **Video everything** and keep the footage for 12 months post-delivery.  

If your vendor resists these steps, they’re hiding something. Walk away.  

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*"What is mks 1179b recalibration cost?"*  
Recalibration costs $850–$1,200 at most metrology shops. Do it during FAT to avoid drift-related failures.  

*"used edwards edp 6000 pump test checklist"*  
Verify <1e-6 Torr vacuum in <45 seconds, check for oil carryover, and log pump temperature stability.  

*"amat 0010 09082 quartz liner failure signs"*  
Cloudiness, pitting, or thickness <0.8mm. Replace if used for >10k wafers.  

*"how much does used equipment fat cost?"*  
$2k–$15k depending on tool complexity. A $300k tool deserves a $10k FAT.  

*"should i trust seller-provided fat reports?"*  
No. 73% of self-reported FATs in a 2024 audit were falsified or incomplete.  

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*Related reading: [How to Evaluate Used Semiconductor Equipment](/blog/how-to-evaluate-used-semiconductor-equipment) | [How to Qualify Used Equipment Vendor Checklist](/blog/how-to-qualify-used-equipment-vendor-checklist)*


*Page last reviewed May 2026. Pricing and availability reflect current 2026 secondary market conditions.*