A method of making an electronic device may include forming at least one circuit layer that includes solder pads on a substrate and forming at least one liquid crystal polymer (LCP) solder mask having mask openings therein. The method may also include forming at least one thin film resistor on the LCP solder mask and coupling the at least one LCP solder mask to the substrate so that the at least one thin film resistor is coupled to the at least one circuit layer and so that the solder pads are aligned with the mask openings.