Method and apparatus for transferring solder bumps
AssigneeInternational Business Machines Corporation
InventorsGuy Brouillette, David Danovitch, Jean-Paul Henry
Life of this patent
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Abstract
The present invention relates to improvements in forming and transferring solder bumps for use in mounting integrated circuit substrates on chip carrier packages. A mold having cavities for the solder bumps is held in contact with a substrate and a compressible device. As the temperature is increased to melt the solder in the cavities, at an appropriate time and temperature, the compressible device is caused to decompress resulting in the mold separating from the substrate and leaving formed solder bumps on the contacts on the substrate. Various mechanisms are described to cause the force holding the mold and substrate together to decrease.
Claims16
A method of transferring solder bumps from a mold to a substrate having a plurality of pads comprising the steps of:
- providing a base member and a substrate located thereon;
- positioning a mold having a plurality of solder elements on said substrate such that each said solder element contacts a corresponding substrate pad and said mold contacts at least one compressible device having a thermally ductile buffer and located on said base member;
- causing said mold to compress said compressible device;
- heating said solder elements such that each said solder element melts and adheres to said corresponding substrate pad;
- and
- causing said compressible device to decompress and thereby separate said substrate and said mold while the solder elements remain in a molten state thereby causing each said solder element to adhere to said corresponding substrate pad in the form of a solder bump.
An apparatus for transferring solder humps from a mold to a substrate having a plurality of pads comprising:
- a base member and a substrate located thereon;
- a mold having a plurality of solder elements and positioned on said substrate such that each said solder element contacts a corresponding substrate and said mold contacts a compressible device located on said base member,
- a first device coupled to said mold for enabling the application of a compressive force to said compressible device;
- a first reflow heating element for melting said solder elements and causing each said solder element to transfer from said mold to said corresponding substrate pad;
- and
- a second device coupled to a thermally ductile buffer for causing said substrate and said mold to separate while said solder elements are melted, resulting in each said solder element adhering to a corresponding pad in the form of a solder bump.
Dependencies are inferred from the claim text.