Which Tergeo fits your lab?Oxygen plasma asher systems
Tabletop oxygen plasma ashers for photoresist stripping, descum and analytical ashing — MEMS, microfabrication, failure analysis and environmental labs. Single wafers up to 8″ or batches in a quartz boat, direct or downstream ashing, with real-time end-point indication.
What a plasma asher does
Oxygen radicals from the plasma react with the photoresist and convert it into volatile CO, CO₂ and H₂O that the vacuum pump removes. Inorganic layers such as Si, SiO₂ and Si₃N₄ are barely touched, so the strip is highly selective — and because it is dry, there is no solvent waste and no pattern collapse from liquid surface tension.
- Ashing / stripping — remove the full resist layer after etch or implant
- Descum — clear thin resist residue from developed openings before etch or plating
- SU-8 and thick resists — use the 500 W option for faster removal
- Downstream mode — radicals only, to protect sensitive device layers
Which plasma asher fits your wafers?
| Tergeo | Tergeo-Plus | Tergeo-Pro | |
|---|---|---|---|
| Wafer capacity | Pieces and small samples | One 6″ wafer or a 4″ wafer boat | One 8″ wafer, or one/two 25/50-slot 6″/4″ boats |
| Chamber | Quartz Ø110 × 280 mm | Quartz Ø160 × 280 mm | Quartz Ø230 × 340 mm |
| RF power (13.56 MHz) | 75 W or 150 W | 150 / 300 / 500 W | 150 / 300 / 500 W |
| Best for | Descum, small-sample ashing | Single-wafer ashing, SU-8, descum | Batch stripping and 8″ processing |
Direct-mode and downstream plasma ashing in one asher
Direct (immersion) ashing puts the wafer in the oxygen plasma for the highest strip rate. Downstream plasma ashing lets only oxygen radicals reach the wafer, avoiding ion bombardment and charging damage on sensitive devices. Tergeo and Tergeo-Plus offer both modes, selected per recipe — plus pulsed operation for very gentle descum.
Asher gases
- O₂ — standard photoresist and organic ashing
- O₂ + CF₄ — faster stripping of hardened or implanted resist, SU-8
- H₂O + O₂ — residue-free strip, hydrophilic finish
- Ar + O₂ — stable discharge, light physical assist
Getting a fast, clean strip
Power and frequency
Ashers run at 13.56 MHz or microwave; low-cost kHz power does not give enough plasma density for practical ashing rates.
Pressure
Ashing typically runs at 0.25–2 Torr. For batches in a wafer boat, keep pressure above 1 Torr so radicals reach between wafers.
End point
Plasma emission changes when the resist clears; the Tergeo plasma intensity sensor shows it in real time to avoid over- or under-ashing.
Plasma ashing application notes
The same low-temperature oxygen plasma that strips resist also removes filters, polymers and carbon from analytical samples and devices.
Asbestos & crystalline silica
Low-temperature ashing of filters for TEM, XRD and FTIR: a 47 mm filter in ≈20 min with the dish only 6–8 °C above room temperature.
Read the note →
Coal & charcoal
1 g powders ashed in 3.5–6 h with end point from plasma emission.
Read the note →
Polyimide
25 µm polyimide removed for failure analysis and biomedical devices.
Read the note →
Parylene
≈230 nm/min parylene removal; 0.3 Ω contact restored on aluminum.
Read the note →Plasma ashing questions
What is a plasma asher?
A vacuum plasma system that removes photoresist and other organic films with oxygen plasma, converting them into gases. It is the dry alternative to solvent strippers such as NMP or DMSO.
How much does a plasma asher cost?
Tergeo ashers are quoted per configuration — chamber size, RF power (up to 500 W), gas lines and pump. Academic and start-up discounts are available; request a quote.
What is the difference between ashing and descum?
Ashing (stripping) removes the entire resist layer. Descum is a short, gentle oxygen-plasma step that removes only the thin residue left in developed openings.
How fast is plasma ashing?
With the 500 W option, Tergeo-Plus ashes photoresist at more than one micron per minute. Rate depends on resist type, power, pressure and load.
Can I strip SU-8?
Yes. Thick SU-8 layers benefit from higher RF power and, where allowed, an O₂ + CF₄ mixture.
Not sure which plasma cleaner fits your process?
Tell us your samples, size and process gas. Our engineers reply within one to two business days with a recommendation and a quote.