Patent ID: 6112975
Filing Date: 2000-09-05
Classification: H01L,H05K,Y10T

Abstract:
A method for attaching spherical and/or non-spherical contacts to a substrate having mounting pads arranged in a predetermined array, said method comprising the steps of:(a) positioning the substrate over a fixture constructed and arranged for supporting said substrate thereon;(b) positioning a stencil over said substrate, the stencil having openings formed therein in said predetermined array, and being held and aligned by said fixture in such a position that the openings of the stencil are aligned with the mounting pads of the substrate;(c) applying soldering paste onto the stencil so as to fill the openings of the stencil wherein a dab of paste is left in the openings of the stencil;(d) removing the stencil from the substrate so as to leave the dab of paste over each mounting pad;(e) positioning a contact loading plate over said substrate, said contact loading plate having openings formed therein in said predetermined array, the openings have a reduced diameter portion, sized to be smaller than a diameter of the contacts, in communication with a larger diameter portion which surrounds the dab of solder paste, and being held and aligned by said fixture in such a position that the openings of the plate are aligned with the mounting pads of the substrate;(f) filling the openings of the contact loading plate with contacts, the arrangement being such that the contacts engage the reduced diameter portion and are partially held above an upper surface of the contact loading plate;(g) applying pressure to the contacts to force the contacts through the reduced diameter Portion of the contact loading plate and into the dabs of paste positioned over the mounting pads;(h) removing the contact loading plate from the substrate and fixture so as to leave the contacts on the dabs of paste provided on said mounting pads of the substrate;(i) removing the substrate from the fixture; and(j) applying heat to the substrate so as to solder the contacts to the mounting pads.