FINE PITCH PRINTING for SURFACE MOUNTED TECHNOLOGY
Original Publication Date: 1987-Dec-01
Included in the Prior Art Database: 2005-Feb-02
In the development of processes for surface mounted technology (SMT), the process of using a metal mask or stencil for printing solder paste has been the preferred method. However, as the distance between component leads has decreased from .050 inch to .025 inch, the need for a printing method that provided finer tolerances arose. In addition, the large chip devices and the PLCC components require a large volume of solder paste while the 25 mm center flat pack components require a small volume of solder paste. These two extremes in volume are difficult to satisfy with the standard process using a single stencil. A method to address these challenges is the double print process. The double print process utilizes two complementary stencils to print the solder paste.