Alpha Omega Semiconductor Inc.

Lei Duan

Ping Huang

Yuping Gong

Hamza Yilmaz

Yueh-Se Ho

Lei Shi

Yan Xun Xue

Jun Lu

Liang Zhao

Ping Wu

Ruisheng Wu

Yi Chen

A method for preparing semiconductor devices in a flip chip process comprises forming deep grooves surrounding each of the semiconductor chips; depositing a first plastic package material to form a first plastic package layer covering front surface of the semiconductor wafer and filling the deep grooves; depositing a metal layer at back surface of the semiconductor wafer after grinding; grinding an outermost portion of the metal layer thus forming a ring area located at back surface around edge of the semiconductor wafer not covered by the metal layer; cutting the first plastic package layer, the semiconductor wafer, the metal layer and the first plastic package material filled in the deep grooves along a straight line formed by two ends of each of the deep grooves filled with the first plastic package material; and picking up the semiconductor devices and mounting on a substrate without flipping the semiconductor devices.

Method for preparing semiconductor devices applied in flip chip technology

A WLCSP method comprises: depositing a metal bump on bonding pads of chips; forming a first packaging layer at front surface of wafer to cover metal bumps while forming an un-covered ring at the edge of wafer to expose the ends of each scribe line located between two adjacent chips; thinning first packaging layer to expose metal bumps; forming a groove on front surface of first packaging layer along each scribe line by cutting along a straight line extended by two ends of scribe line exposed on front surface of un-covered ring; grinding back surface of wafer to form a recessed space and a support ring at the edge of the wafer; depositing a metal layer at bottom surface of wafer in recessed space; cutting off the edge portion of wafer; and separating individual chips from wafer by cutting through first packaging layer, the wafer and metal layer along groove.

Packaging method of molded wafer level chip scale package (WLCSP)

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

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Lei Duan