Patent ID: 6191022
Filing Date: 2001-02-20
Classification: B23K,H01L,H05K

Abstract:
A method for fine pitch placement of solder spheres onto components of an assembly, comprising the steps of:a) providing a base with pockets therein;b) providing a stencil with holes therethrough that is attached to a frame having elevated walls, said frame and said base being mechanically keyed to orient and physically engage together in a single, precise position;c) inserting said components into said pockets;d) aligning said stencil with said base by engaging said frame firmly in contact with said base to thereby rigidly position said stencil relative to said frame so that said stencil is vertically above said base by a precise, repeatable distance and said elevated walls extend vertically from said stencil;e) introducing solder spheres into said frame and onto said stencil;f) moving said solder spheres relative to said stencil to pass a subset of said solder spheres through said stencil into position adjacent said components;g) pouring a remainder of said solder spheres that are not a part of said subset of said solder spheres off of said stencil through a gate in said frame;h) removing said stencil and frame from said base; andi) heating said components to adhere said subset of said solder spheres thereto.