Used ALD Equipment Buying Guide: Process Fit & Acceptance

For a used atomic layer deposition (ALD) system, start with a process requirement sheet and a serial-specific equipment configuration. Ask sellers to quote against both.

ASM describes ALD as a surface-controlled process using alternating precursor and reactant pulses, with inert-gas purges between pulses and self-limiting surface reactions.

Match the installed configuration to your process

Have your process engineer specify the target film, substrate material and geometry, required temperature window, intended chemistry and throughput goal. Ask each seller to document:

• Platform identity: manufacturer, exact model, serial number, chamber identities and installed options.
• Process hardware: precursor delivery configuration, heated lines, valves, flow-control hardware and temperature-control arrangement.
• Process mode: the installed thermal or plasma configuration, with hardware and software evidence for your intended recipe.
• Handling: substrate fixtures, loading method, transfer hardware and the substrate range documented for that configuration.
• Facilities: electrical supply, gases, cooling, pumping and exhaust/abatement requirements from the installation documents.

Treat a missing component or unverified option as an open item in the purchase scope. Require a written engineering assessment before accepting a proposed substitution.

Acceptance: request a witnessed film run

Make acceptance a written part of the purchase proposal. Ask the seller and your process team to agree on a test substrate, recipe, loading condition and measurement plan.

1. Inspect and reconcile hardware. Compare serial labels and installed components with the quotation and configuration list.
2. Review history. Request process-use, maintenance, cleaning and decommissioning records; have qualified personnel assess prior chemistry and safe handling.
3. Check equipment performance. Define temperature, vacuum and delivery-system checks using the applicable OEM procedures.
4. Measure the film. Agree on thickness, within-substrate uniformity, run-to-run repeatability and any composition or electrical measurements your process requires.
5. Preserve the evidence. Require raw metrology results, measurement locations, instrument details and the settings used during the demonstration.

Set numerical limits with the process owner. Do not substitute a generic heater tolerance, chamber photograph or unrelated recipe demonstration for your acceptance criteria.