A 33% improvement in efficiency of wireless inter-chip power delivery by thin film magnetic material for three-dimensional system integration

An improvement in the efficiency of wireless inductive-coupling inter-chip power delivery using thin film magnetic material is introduced for the first time. In order to improve the efficiency, we proposed a method of attaching thin film magnetic material with the capability of highfrequency operation. The attached magnetic material enhances the magnetic flux generated by on-chip inductors. The proposed technique is cost effective since it does not require modification in LSI manufacturing process. To verify the effectiveness of the proposed technique, we designed and fabricated test chips using 0.18 mm complementary metal oxide semiconductor (CMOS) technology. The measured transferred power was improved from 36 to 48mW, at which operational frequency is optimized to 140 MHz. The measured results show that efficiency was improved by 33%.