SURFACE MICROMACHINED HIGH FREQUENCY INDUCTORS IN ELECTROPLATING AND SCREEN-PRINTING PROCESSES

ABSTRACT

In this paper, electroplating, screen-printing, and surface micromachining technologies are utilized to realize integrated high frequency inductors with compatible integration with chips, sensors, and other components. Various micromachined inductors with different geometries and magnetic core materials are investigated for selecting appropriate magnetic materials and geometries for high frequency applications. The processing steps chosen are all low-temperature, which allows the use of low cost substrates such as MCM-L compatible materials. The integrated inductors with electroplated magnetically anisotropic cores have inductance in the range of 1∼ 5 μ H up to 5 MHz, dc resistance in the range of 0.3∼ 1.5 ohms. The screen-printed spiral inductors with composite soft ferrite cores have inductance in the range of 0.3∼ 0.4 μ H at up to 10 MHz, dc resistance in the range of 0.5–1.2 ohms. The large suspended air core spiral-type inductors have inductance in the range of 20∼ 70 nH and quality factors of 50∼ 150 in the range of 400∼ 800 MHz, respectively.

Keywords:

• Surface micromachined inductors
• high frequency
• magnetic alloys
• electroplating
• screen-printing
• low temperature process
• magnetically anisotropic cores
• soft ferrite composites

ACKNOWLEDGMENTS

This research was partially supported by University Technology Research Center (ITRC) of the Ministry of Information & Communication and by the Ministry of Commerce, Industry and Energy in Korea.