Method and apparatus for soldering elements on the corresponding pads of a wafer, in particular a wafer having high-density integrated circuits

Abstract

An apparatus and method of the soldering or bonding of conductive leads to corresponding conductive pads of an integrated circuit chip includes a fixed soldering tool having a soleplate shaped to match the configuration of the pads, and a bench for supporting the chip. The bench is supported by a plurality of vertically moveable rods located with respect to the bench such that the longitudinal axes of the rods intersect the surface of the chip at predetermined fixed points which are located within a surface area of the chip bonded by a rectangular or square line long which the conductive pads are positioned. The movement of each of the rods is controlled by a corresponding actuator mechanism which enables each rod to be independently controlled. By appropriately controlling the movement of each rod, the bench can be made to tilt or oscillate with respect to its central point. In operation, the rods are controlled so as to move a chip carried on the bench into engagement with the fixed soleplate. Thereafter, the forces are applied to each rod so as to vary the force of contact between different groups of conductive pads and the soleplate. By appropriately controlling the forces applied to the rods, the force required for bonding of the conductive leads to the pads can be sequentially applied to different groups of pads, thereby minimizing the total force on the chip which would otherwise be necessary in order to bond simultaneously all of the conductive leads and pads.

Dependencies are inferred from the claim text.