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

Abstract

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.

Software Engineering of Resistive Elements Electrophysical Parameters Simulation in the Process of Laser Trimming

“…The resistor trim curves produced by ResModel agree well with [5,6,23,27,33,34,36]. The "hot spot" locations at the laser cut path and the current directions also correlate very well with [18,20,27,36].…”

“…The "hot spot" locations at the laser cut path and the current directions also correlate very well with [18,20,27,36]. The current load distributions presented in [5,6,22,33] are slightly different. We believe this is due to the visualization features of the specific simulator, not to any errors in the models.…”

“…The authors of [6,10,12,15] used general-purpose simulation software. S. Kaminski, E. Mis, M. Szymendera, and A. Dziedzic used ANSYS [33,34] to develop the new resistor configurations (with three pads) and laser trims. They also compared the simulation results with the actual trimming on the Aurel equipment [35].…”

Circuit Simulation of Film Resistor Laser Trimming with a Measuring Voltage Source

“…A brief description of the process of constructing a model of a rectangular resistive film with a U-cut is given. Additionally, the conformal mapping method is used to study the trimming of resistors with an additional third pad [21] and arbitrary shape resistors [22]. The disadvantage of this method is the lack of universality; in other words, for each cut shape with different parameters, a new model is required.…”

Circuit Simulation of Film Resistor Laser Trimming with a Measuring Voltage Source

“…A brief description of the process of constructing a model of a rectangular resistive film with a U-cut is given. Also, the conformal mapping method is used to study the trimming of resistors with an additional third pad [21] and arbitrary shape resistors [22] The disadvantage of this method is the lack of universality, in other words, for each cut shape with different parameters, a new model is required.…”