Ease of operation
The SC7620 is ideal for the budget-conscious user who demands quality thin film deposition from an easy-to-use instrument. Designed for routine applications, the SC7620 uses a basic magnetron sputter head with a simple-to-replace disc target (gold/palladium as standard). The sputtering head is hinged for easy operation and fitted with electrical safety interlocks. A panel-mounted switch allows the system to be changed between sputter coating and glow discharge modes.
To prevent accidental damage, the high voltage lead is shielded. The plasma current is variable by adjustment of the vacuum level using an argon leak valve with the plasma voltage being preset. For maximum sputter coating efficiency, the gas injector system ensures that argon gas enters the chamber close to the plasma discharge. Venting is to argon.
A suitable rotary vacuum pump is required. The Pfeiffer DUO 6 5m3/hr two-stage rotary vacuum pump is ideal for this purpose.
Fast cycle times, and a height-adjustable specimen stage
The 100 mm/4″ diameter Pyrex cylinder is mounted on an aluminium collar and sealed with O-rings. The small vacuum chamber size means pump downtimes and cycle times are fast and also allow a small economical rotary pump to be used.
The specimen stage is height-adjustable and can easily be removed to accommodate taller specimens. The deposition rate is controlled manually by a 180-second timer with 15-second resolution. Pressure and plasma current are monitored by analogue meters.
Sputtering and SEM carbon coating (option)
The SC7620 will deposit coatings suitable for use with tungsten-filament SEMs and has the advantage of simple operation, ensuring reliability and suitability for general use. It can quickly be converted to deposit carbon by the addition of an optional carbon evaporation attachment, consisting of a switchable voltage power supply and a carbon fibre head (see SC7620-CF below). The carbon attachment comes with an additional glass cylinder. This is taller than the standard sputter coater cylinder and ensures that the distance between the carbon fibre and the specimens is optimal for the evaporation process.
Glow discharge (hydrophilization)
A three-way switch on the front panel allows the SC7620 to be switched to glow discharge mode.
Freshly-made transmission electron microscopy (TEM) carbon support films tend to have a hydrophobic surface that hinders the collection of TEM sections from the surface of water baths and prevents the spreading of suspensions of particles in negative staining solutions. However, after glow discharge treatment with air, carbon film can be made hydrophilic and negatively-charged, thus allowing the collection of TEM sections and easy spreading of aqueous suspensions.
Note: For a fully automated glow discharge solution, see the GloQube® Plus.
A 5m3/hr Pfeiffer DUO 6 two-stage rotary vacuum pump is recommended.
Carbon evaporation attachment
A carbon coating accessory (SC7620-CF), which consists of an evaporation power supply and carbon fibre head, is available. Fitting the optional carbon evaporation attachment is simple – the sputtering head is tilted back on its hinge and replaced with the carbon fibre head. A connection is then made to the power supply. To ensure that the exposed sputtering head cannot be powered when the add-on carbon head is under vacuum, a positive-break mechanical interlock ensures electrical isolation of the sputtering head. For a ‘stand-alone’ SEM carbon coater, see the Q150R E Plus.
Selecting a target
Gold/Palladium (Au/Pd): Supplied as standard and has the same properties (sputtering rate, secondary electron yield, etc.) as gold, but the sputtered grain size is smaller.
Gold (Au): Gold sputter coating is still widely used in many laboratories.
Silver (Ag): Compared to the other metals, it is relatively easy to remove silver and it is therefore useful for museum, forensic and similar specimens.
Palladium (Pd): Sometimes used instead of gold and gold/palladium for x-ray microanalysis.