Motorola Corporation

Wen Xu Zhou

Karl W Wyatt

Daniel Roman Gamota

Andrew Frederick Skipor

Chao-pin Yeh

Chowdary Ramesh Koripella

Grace M O'Malley

George Amos Carson

Sean Xin Wu

Steven C Machuga

Michelle J Morrell

The method (400, 500) and device (200) for reworkable direct chip attachment include a thermal-mechanical and mechanical stable solder joint for arranging connection pads on a top surface of the circuit board to facilitate connection for electronic elements, and affixing a reinforcement having apertures to accommodate solder joints to the top surface of the circuit board to facilitate solder attachment of the connection pads to the electronic elements wherein the reinforcement constrains deformation of the circuit board to provide reliable solder joints and facilitates attachment and removal of electronic elements from the circuit board.

Device for reworkable direct chip attachment

A microelectronic assembly (10) includes an integrated circuit die (12) that is mounted to a printed circuit board (14). The integrated circuit die (12) overlies the printed circuit board (14) and includes an active face (26) that faces the printed circuit board (14) and is spaced apart therefrom by a gap (30). A plurality of solder bump interconnections (32) extend across the gap (30) and connect a plurality of board bond pads (22) with a plurality of die bond pads (28). A polymeric precursor (13) is dispensed onto the printed circuit board (14) about the integrated circuit die (12) and is curable to form a polymeric encapsulant (16). The polymeric precursor (13) is drawn into the gap (30) and forms a fillet (34) overlying the printed circuit board (14). A frame (18) is embedded in the fillet (34), not in direct contact with the board (14), and the polymeric precursor (13) is heated to cure the polymeric precursor (13) to form a polymeric encapsulant (16). The frame (18) is affixed to the printed circuit board (14) within the polymeric encapsulant (16) to provide increased mechanical strength for the microelectronic assembly (10).

Frame embedded in a polymeric encapsulant

A microelectronic assembly (10) includes an integrated circuit die (12) mounted onto a substrate (14) by solder bump interconnections (32). The die (12) and the substrate (14) are spaced apart by a gap (30) that is filled with a polymeric encapsulant (16). The die (12) includes a die perimeter (24) and a face (27) facing away from the substrate (14). A polymeric reinforcement (18) is disposed onto the die face (27) to protect the die (12) and to reduce the effects of thermally induced stresses on the die (12) and the solder bump interconnections (32). The polymeric reinforcement (18) is spaced apart from the die perimeter (24) to maintain a desired peripheral fillet geometry of the encapsulant (16).

Microelectronic assembly including polymeric reinforcement on an

A microelectronic assembly (10) includes an integrated circuit die (12) that is mounted to a printed circuit board (14). The integrated circuit die (12) overlies the printed circuit board (14) and includes an active face (26) that faces the printed circuit board (14) and is spaced apart therefrom by a gap (30). A plurality of solder bump interconnections (32) extend across the gap (30) and connect a plurality of board bond pads (22) with a plurality of die bond pads (28). A polymeric precursor (13) is dispensed onto the printed circuit board (14) about the integrated circuit die (12) and is curable to form a polymeric encapsulant (16). The polymeric precursor (13) is drawn into the gap (30) and forms a fillet (34) overlying the printed circuit board (14). A frame (18) is embedded in the fillet (34) and the polymeric precursor (13) is heated to cure the polymeric precursor (13) to form a polymeric encapsulant (16). The frame (18) is affixed to the printed circuit board (14) within the polymeric encapsulant (16) to provide increased mechanical strength for the microelectronic assembly (10).

Assembly having a frame embedded in a polymeric encapsulant and method

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Atlanta, GA, United States of America

Wen Xu Zhou