Reworkable die attachment
Patent 5268048 Issued on December 7, 1993. Estimated Expiration Date: 
December 10, 2012. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
December 10, 2012. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesMethod for non-destructive removal of semiconductor devices Method of manufacturing a repairable multi-chip module Method of securing surface-mounted devices to a substrate Patent #: 5220724 InventorsApplicationNo. 988638 filed on 12/10/1992US Classes:156/94, Reclaiming, renewing or repairing articles for reuse29/831, Assembling formed circuit to base156/297, Of discrete laminae to single face of additional lamina257/E21.505, Insulative mounting semiconductor device on support (EPO)438/118Including adhesive bonding stepExaminersPrimary: Ball, Michael W.Assistant: Robey, Robert W. Foreign Patent References
International ClassesB32B 035/00H01L 021/58 AbstractAn integrated circuit is reworkably attached to a circuit board in a manner that forms a compliant bond which is stable under conditions of high thermal stress and thermal coefficient of expansion mismatch. A thermoplastic adhesive having a melting temperature higher than integrated circuit operating temperature is coated on the integrated circuit and dried. The adhesive is then cured. The coated integrated circuit is bonded to the circuit board with a thermosetting epoxy having a low curing temperature, such that curing the adhesive does not damage the circuit board. The integrated circuit is readily removed from the circuit board without damaging the board by heating the integrated circuit to soften the bond between the integrated circuit and the circuit board at the thermoplastic adhesive interface. An alternate embodiment of the invention provides a copper plate interface that is soldered to the circuit board, and to which an integrated circuit is permanently bonded. Reworkability is achieved by flowing the solder bond and removing the copper plate/integrated circuit assembly.Other References
Field of SearchReclaiming, renewing or repairing articles for reuseWith removal of defective area to be repaired Of discrete laminae to single face of additional lamina With coating or impregnating a face to be adhered Coating solidified; e.g., by drying, etc., before assembly Of laminae having a different coating on at least two mating surfaces On flat or curved insulated base, e.g., printed circuit, etc. Assembling bases Assembling formed circuit to base Assembling to base an electrical component, e.g., capacitor, etc. With disassembling Directly attached to semiconductor device Chip mounted on chip PRINTED CIRCUIT | |
