An unexpected pump failure stops the entire line. Missed preventive maintenance on dry vacuum pumps is one of the most expensive — and preventable — sources of unplanned downtime in semiconductor fabs.
OHI Tech supplies and overhauls dry vacuum pumps from Edwards, Pfeiffer, and Ebara. We have identified the recurring failure patterns that shorten service life. Here is the checklist.
Bottom Line: N₂ Purge Deficiency Is the #1 Life-Shortener
Process byproducts solidifying inside the pump is the most common cause of early failure. Synchronizing N₂ purge flow and timing with the process recipe alone can significantly extend overhaul intervals.
Screw vs Claw vs Roots — Type Comparison
| Parameter | Screw | Claw | Roots (Booster) |
|---|---|---|---|
| Structure | Interlocking helical rotors | Non-contact hook rotors | Figure-8 high-speed rotors |
| Corrosive gas resistance | High | Medium | Low |
| Powder handling | Excellent | Fair | Not suitable |
| High-speed pumping | Medium | Excellent | Best (booster use) |
| Standalone use | Yes | Yes | No (must combine) |
| Primary application | CVD, ALD | Etch | Booster combination |
Process-Specific Selection
| Process | Recommended Config | Reason |
|---|---|---|
| Etch | Claw + Roots booster | High-speed pumping, Cl₂/HBr resistance |
| CVD/PECVD | Screw | Powder and high-temp byproduct handling |
| Ion implant | Screw | Clean exhaust, near-ultra-high vacuum |
| Sputtering (PVD) | Claw | Metal vapor handling |
| ALD | Screw | Pulse gas response, precise pressure control |
Maintenance Checklist to Double Service Life
Daily:
- Pump body temperature (target: below 60°C)
- Cooling water flow and temperature (act immediately on anomaly)
- N₂ purge flow rate confirmation
- Exhaust line blockage (differential pressure measurement)
- Oil mist filter saturation (common cause of vacuum loss)
- Vibration and noise change (early bearing wear detection)
- 20,000–30,000 operating hours
- Ultimate vacuum degrades by 10%+
- Exhaust noise increases 5dB+ above baseline
OHI Tech Supply Experience
Through our supply and overhaul work with Edwards, Pfeiffer, and Ebara dry vacuum pumps, we have repeatedly confirmed that N₂ purge timing misconfiguration is a leading cause of premature failure. Specific supply case details are available upon request.
FAQ
Q1. Is overhaul or new replacement more cost-effective? Overhaul costs 30–50% of new pump price. If rotor coating and bearings are in good condition, overhaul is the better choice. OHI Tech evaluates condition on receipt and reports feasibility immediately.
Q2. Why does the pump frequently clog in Etch processes? HBr and Cl₂ byproducts solidify as chloride deposits when they cool inside the pump. Prevention: maintain pump heating at 80–100°C and increase purge intensity.
Q3. Do you support brands other than Edwards? Yes — Pfeiffer, Ebara, and other major brands are supported for both new supply and overhaul. Share the pump model and we will confirm availability. Contact: jino.kim@ohitech.co.kr