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US 4,954,453 AGranted
Method of producing an article comprising a multichip assembly
AssigneeAT&T Bell Laboratories
InventorJohn H. Venutolo
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AssigneeAT&T Bell Laboratories
InventorJohn H. Venutolo
Estimating the term…
In methods of producing an article that comprises a multichip assembly, in which the (typically electronic but not excluding opto-electronic) chips are bonded to a substrate by means of spaced-apart localized solder regions (frequently referred to as "solder bumps"), it is frequently desirable to be able to remove a given chip from the substrate and to replace it with another chip. According to the invention, such chip removal is accomplished by a technique that comprises heating the solder bumps between the given chip and the substrate to a temperature below the solidus temperature of the solder in a manner such that a temperature gradient exists across the solder bumps, and applying to the given chip simultaneously a torque and a lifting force sufficient to cause separation of the given chip from the substrate. The technique can be carried out such that the solder bumps remaining on the substrate after chip removal are of substantially uniform height, facilitating attachment of the replacement chip.
Method of producing an article comprising a multichip assembly that comprises a substrate with a multiplicity of electronic subassemblies thereon, a given subassembly attached to the substrate by means of a multiplicity of localized solder regions, the subassemblies to be referred to as "chips" and the localized solder regions to be referred to as "solder bumps";
Dependencies are inferred from the claim text.