Attachment of surface mount devices to printed circuit boards using a thermoplastic adhesive
AssigneeResolution Performance Products LLC
InventorsSteven L. Stewart, Carlton E. Ash
Life of this patent
Estimating the term…
Abstract
An assembly having a surface mounted electronic device mounted onto a printed circuit board and a thermoplastic adhesive applied to the surface mounted electronic device facing the printed circuit board and providing for a gap between the thermoplastic adhesive and the printed circuit board. The assembly is heated at solder reflow temperatures to at least soften the thermoplastic adhesive sufficiently to flow across the gap and provide a thermoplastic adhesive joint between the surface mounted electronic device and the printed circuit board.
Claims93
A sheet of multiple surface mount electronic devices forming rows and columns of solder ball arrays and solid or semi-solid thermoplastic adhesive adhered to available surfaces between said rows or columns or both.
A process for singulating surface mounted electronic devices from a sheet of surface mounted electronic devices forming rows and columns of solder ball arrays and solid or semi-solid thermoplastic adhesive adhered to available surfaces between said rows or columns or both, comprising cutting each surface mounted electronic device from the sheet along the length of the thermoplastic adhesive.
A solid or semi-solid thermoplastic adhesive preform having a shape corresponding to a pre-selected pattern on available surfaces of a sheet of ball grid array integrated circuits.
An assembly comprising a surface mounted electronic device and a printed circuit board defining an assembly gap width between the device and the printed circuit board before solder reflow, said surface mounted electronic device comprising an organic connecting substrate having terminal leads or solder bumps and having a bottom surface facing the printed circuit board, said bottom surface comprising a semi-solid or solid thermoplastic adhesive attached to a portion of the bottom surface, wherein the terminal leads or solder bumps are mounted on landing pads on the printed circuit board, and the thermoplastic adhesive has a height which is less than the assembly gap width to provide a second gap between the thermoplastic adhesive and the printed circuit board.
A process for adhering a printed circuit board having landing pads to a surface mount electronic device comprising an organic connecting substrate having an upper surface and a bottom surface, and solder bumps disposed on a bottom surface or having terminal leads disposed on the connecting substrate, comprising:
- a) attaching a thermoplastic adhesive onto a portion of the bottom surface of the connecting substrate;
- b) mounting the electronic device onto a printed circuit board to form an assembly in which the terminal leads or solder bumps are aligned with corresponding landing pads on the printed circuit board and the adhesive faces the printed circuit board and wherein a gap is provided between the thermoplastic adhesive and the printed circuit board;
- and
- c) heating the assembly under solder reflow conditions effective to provide an adhesive bond between the organic bottom surface of the electronic device and the printed circuit board and effective to provide a solder joint between the connecting substrate and the landing pads on the printed circuit board.
The process of claim 61, wherein the surface mounted electronic device remains bonded to the printed circuit board when deflected around a 0.75″ mandrel.
A process for adhering a printed circuit board comprising landing pads to a surface mount electronic device comprising a connecting substrate having a bottom surface with leads, said process comprising adhering a thermoplastic adhesive onto a portion of said bottom surface, mounting the electronic device onto a printed circuit board to form an assembly in which the leads on said bottom surface are aligned with corresponding landing pads and the thermoplastic adhesive faces the printed circuit board forming a gap between the thermoplastic adhesive and the printed circuit board, followed by heating the assembly under solder reflow conditions effective to provide an adhesive joint between said bottom surface and the printed circuit board, wherein the thermoplastic adhesive comprises a functionalized polyolefin.
A process for adhering a printed circuit board comprising landing pads to a surface mount electronic device comprising a connecting substrate having a bottom surface with leads, said process comprising adhering a thermoplastic adhesive onto a portion of said bottom surface, mounting the electronic device onto a printed circuit board to form an assembly in which the leads on said bottom surface are aligned with corresponding landing pads and the thermoplastic adhesive faces the printed circuit board forming a gap between the thermoplastic adhesive and the printed circuit board, followed by heating the assembly under solder reflow conditions effective to provide an adhesive joint between said bottom surface and the printed circuit board, wherein the thermoplastic adhesive comprises a polyamide resin in an amount of at least 10 wt. %.
A process for adhering a printed circuit board comprising landing pads to a surface mount electronic device comprising a connecting substrate having a bottom surface with leads, said process comprising adhering a thermoplastic adhesive onto a portion of said bottom surface, mounting the electronic device onto a printed circuit board to form an assembly in which the leads on said bottom surface are aligned with corresponding landing pads and the thermoplastic adhesive faces the printed circuit board forming a gap between the thermoplastic adhesive and the printed circuit board, followed by heating the assembly under solder reflow conditions effective to provide an adhesive joint between said bottom surface and the printed circuit board, wherein the thermoplastic adhesive comprises:
- (A) from 5% to 98% by weight of a functionalized polyolefin, and
- (B) from 2% to 95% by weight of a polyamide compound.
Dependencies are inferred from the claim text.