Liquid Crystal Polymers Material of Choice for Fine-Pitch Electrical Connectors
Two New, High-Flow, Low-Warpage Formulations Key to Achieving Today’s Thinner, Smaller, Higher-Density Interconnects
Phoenix, Ariz., U.S. — Today, liquid crystal (or crystalline) polymers (LCPs) are widely used in the electronics industry for a variety of surface-mount technology (SMT), including connectors — for example, small-outline, dual inline memory modules (S/O DIMMs) for laptop computers and flexible printed circuits (FPCs) for smartphones and tablet computers — because these resins provide excellent flow to fill complex geometries in short cycle times, exceptional thermal and chemical resistance, unique mechanical properties, they achieve UL* 94 V-0 flame retardance without needing flame retardant additives, and offal/scrap can be recycled (melt reprocessed). In a growing number of cases, LCPs also are being selected to mold very-demanding fine-pitch connectors, which are smaller, thinner, and designed to be stacked higher than traditional connectors in order to save real estate (space) on printed-circuit boards (PCBs) to meet miniaturization trends for smaller, more compact consumer electronics. To support this trend, Sumitomo Chemical Advanced Technologies LLC (here) has developed two new SumikaSuper™ LCP grades specifically designed to meet the challenging requirements of fine-pitch connectors.
Fine-pitch connectors are a newer type of interconnect useful in PCB designs where space is limited and small centerline or pitch spacing makes larger wire-to-board interconnects impractical. They tend to provide ultra-fine pitch spacing (0.2 to 0.3 mm), are smaller and thinner than traditional connectors, and are optimized for lower profile stack heights (down to 1 mm) but higher stacking density than conventional connectors. Additionally, these high-density connectors must be rugged, reliable, and affordable, must provide high thermal and chemical resistance to survive surface-mount processing conditions as well as to operate in compact devices with less space to dissipate heat. The new SumikaSuper LCP grades for fine-pitch connectors offer excellent processability and low warpage in very-thin wall sections to accurately mold the thin, light, small interconnects and through holes.