Bumping Electronic Components Using Transfer Substrates
A method for forming solder bumps on an electronic component. Providing a transfer substrate having a plurality of solder balls, disposing the transfer substrate on the surface of the electronic component, heating to reflow the solder balls onto the electronic component; and removing the sacrificial substrate. The transfer substrate may comprise a sacrificial film and a metal layer patterned with a mask which is used to form solder balls on the transfer substrate. Or, the transfer substrate may comprise a sheet of material having solder balls embedded at least partially in the sheet. A method of aligning a part being bumped with a transfer substrate, using a shuttle mechanism and an alignment film is disclosed.
1 - 20 . (canceled)
21 . A method for forming solder bumps on a circuitized substrate comprising the steps of:
providing a transfer substrate comprising a sacrificial substrate and plurality of preformed solder balls;
disposing the transfer substrate on the surface of the circuitized substrate;
reflowing the solder balls onto the circuitized substrate; and
removing the transfer substrate;
wherein:
the transfer substrate comprises a sheet of material selected from the group comprising metal, ceramic and glass; and
the solder balls are at least partially embedded in a surface of the transfer substrate.
22 . The method of claim 21 , wherein:
the solder balls extend at least partially out of the surface of the transfer substrate.
23 . The method of claim 21 , wherein:
the transfer substrate is removed after solder balls have solidified on the circuitized substrate.
24 . The method of claim 21 , wherein:
the transfer substrate is reusable.
25 . The method of claim 21 , wherein:
the transfer substrate is a substantially planar sheet having a substantially planar front surface, a thickness, and a back surface.
26 . The method of claim 21 , wherein:
the transfer substrate comprises a sheet of a rigid or semi-rigid material.
27 . The method of claim 21 , wherein:
the transfer substrate comprises a non-wettable material.
28 . The method of claim 21 , wherein:
the transfer substrate comprises holes or depressions extending only partially through the substrate into a front surface thereof.
29 . The method of claim 28 , wherein:
the holes or depressions comprise one of the following geometries: dished out, and hemispherical.
30 . The method of claim 21 , wherein:
the transfer substrate is substantially see-through.
31 . The method of claim 21 , further comprising:
prior to heating, urging the transfer substrate against the circuitized substrate.
32 . The method of claim 31 , further comprising:
urging the transfer substrate against the electronic component using a pressure plate and a sheet of resilient material disposed between the pressure plate and the transfer substrate.
33 . The method of claim 21 , wherein:
the transfer substrate is removed before cooling.
34 . The method of claim 21 , wherein:
the solder balls are at least 50% embedded in the transfer substrate.
35 . The method of claim 21 , wherein:
the circuitized substrate is an electronic component.