Adjustment of Microwave Integrated Circuit (MIC) with Focused Ion Beam (FIB)

Abstract

Microwave Integrated Circuit (MIC) technology allows flexibility for customization design, reduced design cost and time-to-market, and adjusting capabilities not enable with MMIC circuits. Development of radio frequency (RF) devices requires adjusting pads and alternative circuit layouts connected with wire bonding. Circuits cutting are possible but it is coarse, with no precision and requires a costly metallic film deposition by sputtering process. We have developed a cheaper process by previous Ni-P deposition to improve Au film adhesion. However cutting circuits in adjustments became very difficult. Furthermore more complex RF devices may have critical circuits in which adjustment pads or alternative circuits highly influence the performance disenabling its use. Focused Ion Beam (FIB) by its accuracy allows circuit adjusting (milling circuit lines) with high accuracy. A dual coupler filter in a MIC technology was adjusted using this process. Results demonstrated adjustment is simple and precise in agreement with electromagnetically simulated circuits.