Chip Removal Method
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-27
The proposed removal method is used for a single, flip-chip mounted semiconductor chip soldered to a multi- or single-chip substrate by solder balls. Chips 1 are removed and lifted off substrate 3 by heating solder pads 2. Instead of being applied from the outside, the heat for melting solder pads 2 is produced in chip 1 to be lifted off. In an additional step, prior to sawing a wafer into chips 1, metallized conductor structures, forming a resistance network 4, are applied to the back of the chips. A current source is connected to resistance network 4 by connectors 5 and contacts 6. The heat produced by the current flow in resistance network 4 can be accurately controlled as a function of the current characteristic, without affecting adjacent chips.