Active Resistor Position Sensing
Original Publication Date: 1986-Feb-01
Included in the Prior Art Database: 2005-Mar-08
Active resistor position sensing allows for the alignment of thin-film resistor patterns on a substrate without expensive optical alignment equipment. Thick-film processing allows the top-surface circuit patterns to be aligned with the substrate. When a part is further processed, for example, by laser trimming, the alignment is achieved with special carriers that hold each part at its edges. However, using existing laser trim tools the alignment repeatability of thin-film resistors on top of multi-layer ceramic substrates is not adequate for substrate alignment. This technique forms L-shaped alignment resistors in opposite corners of each substrate (Fig. 2). One terminal of each resistor connects to the ground plane, allowing this end of the resistor to make contact through the connection of the substrate ground pin.