Volume Control of Plated Solder Pad Arrays
Original Publication Date: 1992-Jul-01
Included in the Prior Art Database: 2005-Mar-23
Electroplating of large area arrays of solder bumps is a cost-effective alternative to evaporation and sputtering for the fabrication of high density arrays of solder pads on chips and substrates for microelectronic and optoelectronic interconnect and assembly applications. However, due to the problems in controlling plating parameters over large areas containing a large number of solder pads, it is difficult to avoid local variations in the height and volume of the pads. One solution is to use very slow plating rates to minimize these problems but one cannot eliminate them totally. Variation in solder volume is undesirable since it would result in uneven joint heights when components are assembled or, in the extreme case, lead to unjoined contacts if the variations are too large.