New Trim Configurations for Laser Trimmed Thick-Film Resistors – Experimental Verification

Laser trimming is the most effective and popular trimming method of thick-film and LTCC resistors at present. It is also still a subject of continuing theoretical and experimental analysis and optimization. Very recently a new approach to this process was suggested. It consists in replacing two-contact bar resistors by three-contact distributed structures trimmed by narrow cuts just around additional contact of different shape [1,2]. This paper presents experimental verification of such an approach. The relative trim characteristic and sensitivity are analyzed as a function of additional contact shape and cut length. Next long-term stability, pulse durability and low frequency noise are compared for two- and three-contact resistors versus trim pathway length. These investigations are completed by simulation of electrical potential distribution in two- and three-contact resistors with various length of trimming kerf.