Laser Microwelding of Tape Automated Bonding Components for Surface-Mounted Technologies
Original Publication Date: 1988-Nov-01
Included in the Prior Art Database: 2005-Feb-15
As component pitch becomes smaller, i.e., 4-mil lead on 8-mil center, solder attachment of surface-mounted technology (SMT) components becomes more difficult. Laser microwelding provides an alternate interconnection technique (solderless attachment). It also eliminates common solder problems, such as solder bridging and flux application/removal, and eliminates existing steps, such as stencil design, screening of solder paste, high temperature reflow, and post-cleaning operation. (Image Omitted) In this method, a pulsed Nd:YAG laser is used to weld tape automated bonding (TAB) outer leads onto a circuit card. A schematic welding process is shown in Figs. 1, 2, 3, and 4. The process can be summarized as follows: A. The TAB component is placed onto the circuit card (Fig.