Alpha Omega Semiconductor Inc.

Ruisheng Wu

Ping Huang

Tao Feng

Yuping Gong

Lei Shi

Yueh-Se Ho

Zhiqiang Niu

Yan Fei Liu

Lei Duan

Yi Chen

A substrate-less composite power semiconductor device may be fabricated from a vertical conductive power semiconductor device wafer that includes a top metal layer located on a top surface of the wafer by a) forming solder bumps on top of the top metal layer; b) forming wafer level molding around the solder bumps such that the solder bumps are exposed through a top of the wafer level molding; c) grinding a back side of the device wafer to reduce a total thickness of a semiconductor material portion of the device wafer to a final thickness; and d) forming a back metal on a back surface of the wafer.

Substrateless power device packages

A substrate-less composite power semiconductor device may include a thin substrate and a top metal layer located on a top surface of the substrate. A total thickness of the substrate and the epitaxial layer may be less than 25 microns. Solder bumps are formed on top of the top metal layer and molding compound surrounds the solder bumps and leaves the solder bumps at least partly exposed.

A chip-scale packaging method, with bottom and side of a semiconductor chip encapsulated, includes the following steps: attaching backside of a thinned semiconductor wafer to a dicing tape; separating individual chips by cutting from front side of the wafer at scribe line but not cut through the dicing tape; flipping and attaching the wafer onto a top surface of a double-sided tape, then removing the dicing tape; attaching bottom surface of the double-sided tape on a supporting plate; filling the space between adjacent chips and covering the whole wafer backside with a molding material; flipping the whole structure and remove the supporting plate; placing solder balls at corresponding positions on electrodes of each chip and performing backflow treatment; finally separating individual chip packages by cutting through molding material at the space between adjacent chip packages with molding material encapsulating the bottom and side of each individual semiconductor chip.

Wafer level packaging method of encapsulating the bottom and side of a semiconductor chip

A wafer level chip scale package and method of laser marking the same are disclosed. The method includes forming a plurality of semiconductor devices on a frontside surface of a wafer, metallizing device contacts on the frontside surface of the wafer, grinding the backside surface of the wafer, silicon etching the backside surface of the wafer, laser marking the backside surface of the wafer following the silicon etch step, oxide etching the backside surface of the wafer following the laser marking step, depositing a metal layer on the backside surface of the wafer following the oxide etch step, and dicing the wafer into wafer level chip scale packages. A wafer level chip scale package includes a mark formed on a backside surface thereof, the mark comprising a plurality of trenches formed in a silicon backside surface and corresponding indentations formed in an overlaying back metal layer.

Growing community of inventors

Shanghai, China

Ruisheng Wu