Fluidized-bed Solder-leveling Technique
Original Publication Date: 1986-Mar-01
Included in the Prior Art Database: 2005-Mar-08
A fluidized bed consists of a bed of sand and a heated gas such as air or an inert gas such as nitrogen which is passed through the bottom of the bed. By judiciously selecting the grit size of the sand and the temperature of the gas, the solder on electrical components such as the contacts of an integrated circuit chip carrier, e.g. a ceramic substrate, is placed in the molten state when immersed in the bed. The agitation of the sand, produced by the movement of the gas passing through it, and the resulting abrasion of the sand causes the excess solder on the contact to be leveled to a desired clearance or height tolerance. The substrates can be processed through the sand bed in batch or continuous modes.