Maintenance and upgrades
Converting oil-sealed pumps to dry pumps on older process tools
When a dry pump conversion pays off on an etcher, CVD tool or evaporator, how to size the replacement and what changes in facilities and interlocks.
Upgrades
Dry pump conversion for etch, CVD and implant tools
We replace oil-sealed roughing pumps with dry pumps sized to your process, and adapt the foreline, purge and exhaust, to end oil changes and oil back-streaming.
Why convert to dry pumps
Many older etch, PECVD, LPCVD, sputter and implant tools were built with oil-sealed rotary vane roughing pumps. On a clean process they are reliable. On a corrosive or deposition process they are a constant job: the oil degrades and must be changed often, filters and oil mist eliminators load up, and spent oil is hazardous waste because it carries process residue. Under some conditions oil vapour can also back-stream into the foreline and towards the chamber.
Corrosive processes often run these pumps on PFPE oil to resist attack, which adds to the consumable cost. A dry pump conversion replaces the oil-sealed pump with a pump that has no oil in the pumping path. For the longer reasoning and the pitfalls, see converting oil-sealed pumps to dry pumps.
Choosing the pump
The pump has to match the process, not only the tool. We look at:
- Gases and by-products: corrosive, condensable or particle-forming chemistry needs a pump built for it
- Gas flows and process pressure, which set the pumping speed needed at the operating point
- Duty cycle: continuous process pumping or intermittent load-lock pumping
- Base pressure and pump-down time the process needs
- Facilities: N2 purge, cooling water, power and exhaust at the pump location
- Noise and footprint in your sub-fab or service chase
Multi-stage roots and claw dry pumps are typical for corrosive and deposition duty. Scroll pumps suit clean, low-load uses such as load locks and some metrology tools. We state the type and the reasons in the proposal.
Scope
A typical conversion covers:
- Decontamination of the old pump and foreline before they are opened, if the tool ran toxic or corrosive chemistry
- Removal of the oil pump and disposal of the oil through a proper waste route
- Cleaning of residual oil from the foreline and replacement of oil-soaked flex lines and seals
- Installation of the dry pump with N2 purge, exhaust connection and cooling where needed
- Wiring of pump status into the tool interlocks, so the tool stops safely if the pump faults
- Adjustment of foreline traps and, where fitted, exhaust abatement connections
If the pumps are being replaced anyway during a vacuum system refurbishment, the conversion is done in the same stop.
Typical downtime
Downtime is set mainly by facilities work at the pump location, such as a new purge line, cooling water or a power supply. If those are prepared in advance, the swap and verification on the tool are usually a short planned stop. The proposal states the planned downtime.
What we need from you
- The process gases, flows and pressures the tool runs
- The pump location, with available power, cooling water, N2 and exhaust
- Your waste route for spent oil, or permission for us to dispose of it
- Access to the tool interlock wiring for the pump status connection
Results and documentation
You receive the sizing note, before and after vacuum data, a facilities list and the service interval for the new pump. The upgrade applies widely to etch tools, deposition tools and implanters.
How it works
Step by step
Process review
We review the gases, flows, pressures and duty cycle the pump has to handle.
Pump selection
We propose a dry pump type and size, with its purge, cooling and power needs.
Install
Our engineers remove the oil pump, clean the foreline and fit the dry pump with purge and exhaust.
Verify
We compare pump-down time, base pressure and process pressure control with the baseline.
Deliverables
What you receive
- Process review and pump sizing note
- Installed dry pump with N2 purge, exhaust and interlocks connected
- Foreline cleaned of oil, with new seals and flex lines where needed
- Before and after pump-down time, base pressure and pressure control results
- Facilities list for the new pump and its service interval
Equipment
Tools this applies to
FAQ
Questions and answers
Why replace an oil-sealed pump that still works?
On corrosive or deposition processes oil pumps need frequent oil changes, the oil carries process residue into the waste stream, and oil can back-stream into the foreline. A dry pump removes those problems and usually lowers routine maintenance.
Does a dry pump need more facilities than an oil pump?
Often yes. Many dry pumps need N2 purge, cooling water and more electrical power than the oil pump they replace, so we confirm facilities before choosing the pump.
Which type of dry pump do you fit?
It depends on the process. Multi-stage roots and claw pumps are common on corrosive and deposition processes, and scroll pumps suit clean, low-load duty such as load locks.
Do we need to change the foreline?
Usually only partly. We clean out residual oil, replace flex lines and seals that are oil-soaked or damaged, and add a purge connection if the pump needs one.
Guides
Related guides
Next step
Talk to us about your tool
Tell us the tool and what you need. We scope the work and send a written offer.