Motorola Corporation

Steven Lewis Wille

Daniel Roman Gamota

Colleen Mary Walsh

Thomas A Knecht

Steven Michael Scheifers

Michael Hertsberg

A microelectronic assembly (,) includes a printed circuit board (,) that includes a substrate (,) having a die attach region (,) and a plurality of first bond pads (,) disposed and spaced apart at the die attach region (,). A channel (,) effective in improving fluid flow extends across the die attach region (,) apart from the first bond pads (,). An integrated circuit die (,) is mounted onto the printed circuit board (,) and includes a major face (,) facing the substrate (,) and spaced apart therefrom by a gap (,) and second bond pads (,) disposed on the major face (,) in a pattern such that each of the second bond pads (,) registers with a first bond pad (,). Solder bump interconnections (,) connect the first bond pads (,) to the second bond pads (,). Encapsulant (,) is disposed within the gap (,) and flows over the substrate (,) and the channel (,) to encapsulate the solder bump interconnections (,). Channel,enhances the flow of the precursor (,) in the gap (,) prior to curing the precursor (,) to form the encapsulant (,).

Method and assembly for providing improved underchip encapsulation

A microelectronic assembly (10) includes a printed circuit board (12) that includes a substrate (14) having a die attach region (22) and a plurality of first bond pads (24) disposed and spaced apart at the die attach region (22). A channel (26) effective in improving fluid flow extends across the die attach region (22) apart from the first bond pads (24). An integrated circuit die (16) is mounted onto the printed circuit board (12) and includes a major face (28) facing the substrate (14) and spaced apart therefrom by a gap (30) and second bond pads (25) disposed on the major face (28) in a pattern such that each of the second bond pads (25) registers with a first bond pad (24). Solder bump interconnections (18) connect the first bond pads (24) to the second bond pads (25). Encapsulant (20) is disposed within the gap (30) and flows over the substrate (14) and the channel (26) to encapsulate the solder bump interconnections (18). Channel 26 enhances the flow of the precursor (19) in the gap (30) prior to curing the precursor (19) to form the encapsulant (20).

A microelectronic assembly (10) includes an integrated circuit component (14) spaced apart from a substrate (12) by a gap filled with a polymeric encapsulant (18). The polymeric encapsulant (18) contains a thermally decomposable azide group. In the event that it is necessary to remove the component (14), such as if the component (14) is found to be defective, the microelectronic assembly (10) is heated to a temperature above the decomposition temperature of the azide group. Decomposition of the azide group disintegrates the encapsulant (18) and preferably detaches the component from the substrate (12), thereby permitting replacement of the component (14).

Microelectronic assembly including a decomposable encapsulant, and

A solution (20) is dispensed onto bond pads (18) on a substrate (14). An integrated circuit component (12) that includes solder bumps (16) formed on component bond pads (30) is superposed onto the substrate (14) such that the solder bumps (16) rest against the bond pads (18). The solution (20) includes an anhydride compound that acts as a fluxing agent. The subassembly (11) is heated to a temperature sufficient to bond the solder bumps (16) to the bond pads (18) to form solder bump interconnections (26). During the bonding process, the fluxing agent substantially vaporizes and leaves virtually no residue on the substrate (14) to allow the component (12) to be effectively underfilled with a polymeric encapsulant (24).

Method of holding a component using an anhydride fluxing agent

A method of hermetically encapsulating a crystal oscillator using a thermoplastic shell. A first step (102) includes molding a thermoplastic shell defining a cavity around a periphery of oscillator locations on a lead frame. A second step (104) includes attaching oscillator components including a piezoelectric element, capacitors and an integrated circuit to the lead frame. A third step (106) includes dispensing an encapsulant within the cavity defined by the thermoplastic shell to encapsulate the oscillator components. A fourth step (108) includes curing the encapsulant. A last step (110) includes excising the oscillator from the lead frame and the leads are formed for mounting.

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Palatine, IL, United States of America

Steven Lewis Wille