Technology

Explaining Thin Film Evaporation

Article written by Anextek, a technology blog

In ion beam assisted deposition, metal is evaporated. The process that occurs is very different from what occurs when water is evaporated. For one, more extreme temperatures are needed to melt the metal, but the end result is very different. Water boils and evaporates, condensing on the surface of an object in the form of beads of water.

Thin film evaporation dilutes the metal to form a gaseous cloud that evenly distributes the material over the interior of the evaporator. Gravity forces the heated material to fall downward into the thermally heated sections, while rotor blades spread the materials over the surface of the heated object.

The process of drawing material through the rotor blade creates a turbulence, which is an intentional feature, and forces it to come into continuous contact with the object the manufacturer wants to coat. This also prevents manufacturers from overheating a specific part of the object by evenly distributing the particles.

The process also attains vaporization rapidly. Occasionally, low output rates may necessitate an additional ring to act as a kind of dam, which forces the materials to pool in the lower portion of the thermal evaporator.

The vapors that escape travel upward then are separated from the incoming feed through passage of the distribution ring. Any liquids left over from the vapor stream are trapped in the vapor chamber that drains them back into the thermal section. This creates “liquid free” vapors that can be condensed and applied to the substrate. The rest of the particulate matter is discharged through a cone at the bottom of the apparatus.

Bio: Denton Vacuum, LLC manufactures UHV sputter deposition systems for medical and industrial applications.