IMPROVED STRENGTH FOR CONDUCTIVE EPOXY SURFACE MOUNT ATTACHMENT
Original Publication Date: 1998-Mar-01
Included in the Prior Art Database: 2002-Jun-28
When applying conductive epoxy as a substitute As a solution to both conductive epoxy surface for solder in surface mount assembly (Figure la), mount challenges, a surface mount adhesive is two significant challenges are encountered. The first applied between the substrate pads (Figure 2a). challenge occurs during placement when the con- When the component is placed on the epoxies, the ductive epoxy spreads under small chip components surface mount adhesive prevents shorting under the making shorting possible (Figure lb). The second component as the conductive epoxy is compressed challenge is poor cohesive strength in the conduc- (,Figure 2b). After curing the epoxy system, the tive epoxy that is often lower than needed to perma- component adhesion is substantially improved; nently attach the part; pull testing always creates pull testing often results in cohesive failure in the cohesive failure in the conductive epoxy (Figure I c). substrate (Figure 2~).