Abstract:The use of Tantalum (Ta) electrolytic capacitors as embedded components constitutes a promising strategy to extend the application of embedded capacitors, because Ta electrolytic capacitor can provide both high capacitance and excellent stability. However, the huge thickness of conventional Ta electrolytic capacitor makes it hard to be embedded in a printed circuit board or substrate. In this work, we propose to employ the electrochemical etching of thin Ta foils to fabricate the anode of Ta electrolytic capacitors for embedded application.The specific capacitance of electrochemically etched Ta anode reaches as high as 74 nF/mm2 when measured in 0.1 mol/L H2SO4.The etched Ta anode is then fabricated into electrolytic capacitors, and a stable capacitance of >30 nF/mm2 is demonstrated in the frequency range from 100 Hz to 1 MHz and a low leakage current of 2.7×10-6 A for a duration of 1 200 seconds at a direct voltage (DC) of 10 V. The whole thickness of the capacitor is decreased to~75 μm.