Osmium coater NEOC-PRO

Overview

The Meiwafosis NEOC-PRO (Neo Osmium Coater) deposits a thin film of metallic osmium (Os) on sample surfaces by vapor-phase deposition. It is used for charge-up countermeasures and conductive pre-treatment before electron microscopy observation. Compared to sputter coaters, it causes less damage to samples and enables shorter processing times.

Features

• Uniform deposition of metallic osmium (Os) thin film (film thickness controllable via discharge current × discharge time)
• Lower damage and shorter processing time compared to sputter coaters (well-suited for charge-up countermeasures)
• Multiple samples can be processed simultaneously (load multiple samples into the chamber at once)
• Effective pre-treatment for non-conductive samples such as biological specimens, polymers, and ceramics before SEM/TEM observation

Specifications

Manufacturer	Meiwafosis Co., Ltd.
Model	NEOC-PRO
Chamber dimensions	Φ150 × 70 cm³
Osmium ampule	Wako Pure Chemical Industries (500 mg)
Location	1-111

Recommended Coating Conditions

Discharge current	5 mA (manufacturer recommended)
Vacuum level during coating	10 Pa (optimal for 5 mA discharge)
Ultimate vacuum (pre-coating)	≤2 Pa (≤1 Pa for porous or thin-film samples)
Os gas introduction time	Hold sublimation tube at OPEN for 90 seconds

The amount of osmium deposited is proportional to discharge current (mA) × discharge time (seconds). At 5 mA with a discharge time of 0–25 seconds, a film thickness of approximately 0–6 nm can be obtained (based on the film thickness/deposition time data in the manual).

Basic Operating Procedure

1. Place the sample on the cathode (lower electrode). Always place an insulating material such as a Teflon sheet (≤7 cm square) under the sample or sample stage.
2. Press the MAIN switch to start the unit and vacuum pump, then evacuate the chamber to ≤2 Pa.
3. Rotate the sublimation tube 180° counterclockwise to the OPEN position and allow Os gas to fill the chamber (hold for 90 seconds).
4. Adjust the needle valve to set the vacuum level for coating (target: 10 Pa for 5 mA discharge).
5. Set the discharge time using the timer, then press the COAT switch to start discharge and deposition (a blue-violet plasma is visible during discharge).
6. After discharge ends, promptly rotate the sublimation tube 180° clockwise to return it to the CLOSE position.
7. Returning the tube to CLOSE triggers the automatic exhaust sequence (alternating 20-second air introduction and 20-second evacuation, repeated 3 times).
8. After the automatic exhaust sequence ends, turn off the power with the MAIN switch, then open the chamber and remove the coated sample.

Important Notes

• Use of insulating material: Always place an insulating material such as a Teflon sheet (≤7 cm square) under the sample. Without it, stable discharge is not possible. Samples with sharp edges or those that are electrically conductive may spark if placed directly on the cathode.
• Close the sublimation tube promptly: Return the sublimation tube to CLOSE immediately after discharge ends. Leaving it OPEN increases running costs due to continued Os gas consumption.
• Exhaust handling: Osmium is a hazardous substance. Always route the vacuum pump exhaust hose to a fume hood or to the outside through a window.
• Ampule type: Only Wako Pure Chemical Industries osmium ampules (500 mg) are compatible. Other manufacturers’ products may not fit the sublimation tube.
• Low-temperature environments: In cold weather or cool rooms, the ampule may not sublimate sufficiently. Warm the sublimation tube by hand before use.
• Unstable discharge: After cleaning, residual cleaning agents may cause unstable discharge. Perform 2–3 test discharges (5 mA, 10 seconds each) with a blank chamber before coating actual samples.

Manual

Manual: Osmium Coater Manual (PDF, campus access only)

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