Heating Module 800° C
A heating module for the observation of small specimens in the SEM must fulfill several requirements. There must be an orifice at the top. Its diameter depends upon how far the specimen stage with the heating module on top of it must be tilted. The temperature transfer from the module to the stage mechanics should be as low as possible.
To achieve that, the heating cylinder was placed in a forklike structure, and it is held in place there with three tips. A multi-layer reflecting shield inside the furnace focuses the radiation back towards the center area, where the specimen is located.
A resistance heater, shaped like a miniaturized ceramics "beehive" with a round hole in the middle. A metal cylinder is inserted there, to serve as a specimen platform or holder, it may have all kinds of useful shape - usually a mold in the central area. Disk shaped specimens can be held down with little tungsten springs. It is also quite important, that the heater does not produce any electrical fields, which may distort the electron image.
The PID-controller (Power supply), the vacuum flange, all cable, the water cooling and an attachment kit are part of the shipment volume.
Specifications Standard Heating Module 800° C
You may choose between a "PID" type, and a manual controller. The PID-controller (usually equipped with a PC interface) pilots the temperature according to the physical parameters, and after an initial "learning"-routine, which is only done once; the heating rate can be selected. The controller finds this experiment temperature following a time-temperature-ramp without oscillations. The manual heating controller requires the attention of the operator, who changes the current in the heater and observes the digital indicator. This is a bit slower, but extremely stable after reaching thermal equilibrium.
RT to 300, 500 or 800 degrees, depending upon the required design. Various methods of attaching the specimen, according to your requirements.
Attaching the Module to the SEM Stage
The heating module is mounted to the SEM stage like a "large specimen". The stage takes over the xy-movement - sometimes a small amount of tilt too - with the module, and (if mounted) with the prober needles in place. Caution with liquefying samples! There are vacuum feedthroughs in the shipment volume.
Dimensions: Approx. 100 mm x 50 mm x 40 mm. The base plate is shaped so that it will never touch the chamber wall when opening the stage door. The furnace is lined with several concentric layers of reflective, high temperature resistant sheet metal. The whole structure rests on three sharp tips. This point contact, together with the shielding, keeps heat dissipation into the stage mechanics very low.