Authored By:
Bruce P. Mahler, Vice President
Ohmega Technologies, Inc.
Culver City, CA, USA
Summary
Micro Trace Resistor Technology allows thin film resistors to be built within a printed circuit trace that is less than 100 microns wide. Using standard subtractive printed circuit board processes, it is ideal for high density interconnect (HDI) designs where passive component placement is difficult or impossible.
By utilizing the differential processes unique to the OhmegaPly nickel phosphorous (NiP) resistive material, copper traces can be imaged and etched to define resistor widths that are precise and sharply defined, resulting in the creation of miniature resistors with consistent ohmic values. With low inductance and good tolerances, Micro Trace Resistors are ideal for line termination and pull-up/down applications.
Conclusions
The results of the micro trace resistor test vehicle showed that resistors with line widths less than 100 microns can be successfully built with good tolerances and acceptable power ratings. The production of such resistors was enabled by the convergence of specialized manufacturing technologies of Laser Direct Imaging and NiP differential etching. The resulting test data provided insight into the mechanisms that yielded better tolerances in the micro trace resistors across a range of sheet resistivities.
This insight subsequently directed the research and development of an improved NiP resistive alloy with greater processing stability and tighter tolerances for micro trace resistors.
Initially Published in the IPC Proceedings
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