Controlled Welding Cycles for Bonding Wires
Original Publication Date: 1982-Dec-01
Included in the Prior Art Database: 2005-Feb-10
In semiconductor packaging technology it is well known to bond wires to interconnection pads on the device and/or the supporting substrate. The wires to be bonded are frequently coated with a polyimide insulation which is stripped from the wire in the region to be bonded. The stripped wire portion is then placed at the bonding location, a laminated electrode brought into contact with the wire under positive pressure, and a predetermined, fixed welding pulse applied through the electrodes. The welding pulse passes through the wire, melting it locally and joining the wire to the pad. If, however, there is an insulation film remaining on the wire and the shape of the tip and the applied force does not break through this film, no welding current flows and no bond is made.