Co-deposition of C and Ni-P to fabricate high-ohmic resistor for board-level integration with on-line monitoring method

Embedding thin-film resistance (ETFR) in printed circuit boards (PCB) is of great significance for precise circuit designing and is thus widely applied in analogous circuits. This work introduces diethylenetriamine (DETA) into Ni-P electroless-plating solution to obtain C-doped Ni-P high-ohmic value resistor with square resistance over 400 omega/sq. During the deposition, a referred resistor is monitored on-line to indicate the resistance of other embedded resistors, achieving a confined resistive error within +/- 10 %. This reduced resistive error primely satisfies the developing demand for the effective transmission of signal. The effects of DETA content, temperature and pH values on resistances were studied to optimize the Ni-P-C composition, yielding the highest ohm value of 731 omega/sq. Rectangular and serpentine resistors with varied sizes were fabricated to confirm the realizability of this proposed method. The results of experiments including lamination processing and temperature coefficient of resistance (TCR) tests suggest the thermal as well as mechanical stability of the fabricated embedded resistor for PCB manufacture. The HFSS simulation for comparison between the parasitic effects of surface mounted tech-nology resistor (SMTR) and ETFR indicates that the prominent performance of the developed resistor is compatible with ETFR components.