Patent ID: 6584897
Filing Date: 2003-07-01
Classification: B41F,B41M,B41N,H01L,H05K

Abstract:
A method for forming substantially vertical elements of paste on an object having a surface comprising:providing a stencil having a plurality of apertures formed therethrough from a top surface of said stencil to a bottom surface of said stencil, at least one aperture of said plurality of apertures including a first portion having a first cross-sectional area formed by a first wall portion having a first diameter and extending generally vertically from said top surface of said stencil, a second portion of said at least one aperture of said plurality of apertures adjacent said bottom surface of said stencil and having a second cross-sectional area formed by a second wall portion having a second diameter larger than said first diameter of said first wall portion and extending generally vertically from said bottom surface of said stencil, said stencil having a thickness in the range of from 0.1 to 10 times said first diameter of said first wall portion of said at least one aperture of said plurality of apertures, and at least one sloped annular shoulder having a shape located between said first wall portion and said second wall portion of said at least one aperture of said plurality of apertures; applying said stencil to a surface of said object; extruding said paste, said paste having a viscosity in the range of between 30K to 310K centipoise through said plurality of apertures formed in said stencil; wiping said paste across said top surface of said stencil to force said paste through said plurality of apertures; preventing contact of said paste with a portion of said second wall portion of said at least one aperture of said plurality of apertures during said extruding of said paste by said second cross-sectional area of said second portion of said at least one aperture of said plurality of apertures being larger than said first cross-sectional area of said first portion of said at least one aperture of said plurality of apertures; and removing said stencil and leaving portions of said paste in a substantially vertical column.