Plating Speed
Length of time for a plating cycle to complete the process of growing a part. Speed is dependant on current set, and amp-hours.

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January 15, 2009

LIGA and MEMS Plating 

LIGA is a German acronym for "Lithographie, Galvanoformung, Abformung" which describes a methodology utilizing lithography, electroplating and molding to create high aspect ratio MEMS (Micro Electrical Mechanical System) structures.

The LIGA process was developed in the early 1980s by a team under the leadership of Erwin Willy Becker and Wolfgang Ehrfeld at the institute for Nuclear Process Engineering at the Karlsruhe Nuclear Research Center.  LIGA was one of the first major techniques to allow on-demand manufacturing of high-aspect-ratio structures (structures that are much taller than wide) with lateral precision below one micrometer.

Today there are several variations of LIGA being employed including the use of UV exposure of hard photoresists such as SU-8. 

From and electroplating perspective, all LIGA utilizes a master in which the metalized layer (seed layer) is underneath the photoresist structures. This is in contrast to techniques where the conductive layer is over the photoresist. Because the conductive layer is at the base of the structures, the electroplating process will fill the structures from the bottom up, insuring good deposition down to the very bottom of deep structures.

Conversely, if the seed layer is over the photoresist, deep structures may have voids at the base as the plating deposition tends to plate the top of the structures first.