P-channel chip-scale lateral power MOSFET for portable electronics applications

P-channel power MOSFETs are widely used in portable electronics products as the load switch. We report a new 12 V P-channel chip-scale lateral power MOSFET with ultra-low on-resistance and small package footprint. The product of RDS (ON) and footprint area of the lateral MOSFET is reduced by nearly 50% comparing to the conventional trench MOSFET with the same voltage rating. We have developed an innovative metal interconnect and chip-scale packaging approach to overcome the "scaling issue" which limits the chip size and current rating of traditional lateral power devices. The lateral MOSFET is designed and fabricated based on a standard 0.5 /spl mu/m CMOS process, and packaged in flip-chip forms using a wafer bumping technology. P-channel Lateral Power/sup /spl trade// MOSFETs provide a good solution for load switching in all sorts of battery-powered portable electronics products.