Conductive Ink Traces June 14, 2006
Conductive ink, for example the Dow Corning PI-2000 series of Silver Polymeric Interconnect Materials, can be used to print conductive circuit traces. Generally, the ink is applied using a screen printing technique, with typical print thicknesses of 25 um to 40 um. Sheet Resistivity is specified in milliohms/square at a 25 um print thickness and varies from 8 to 81 for the currently available inks. For comparison, copper has a Sheet Resistivity of 0.68 milliohms/square at a 25 um thickness.
The Sheet Resistivity can be used to calculate the resistance of the printed traces as follows:
Resistance = Sheet_Resistivity*(Length/Width)*(Ref_Thickness/Thickness)
where "Ref_Thickness" is the thickness at which the "Sheet_Resistivity" is specified in the ink's data sheet and "Thickness" is the actual thickness of the ink you are printing.
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