Reliability, performance and economics of thermally enhanced plastic packages

Thermal demands on electronic packages are increasing. Resolving these issues in plastic packaging frequently involves a balance of engineering, performance and cost. Conventional plastic packages exhibit limited thermal performance. Thus, engineering solutions, such as modified lead frames, heat sinks or spreaders, which often involve a significant increase in cost, must be considered in those applications where heat dissipation requirements exceed design capabilities. The use of a novel hydrolytically-stable aluminum nitride filler (SCAN), replacing standard fused silica fillers, in transfer molded plastic packages offers another option. AlN is an inorganic dielectric possessing a thermal conductivity much higher than standard silica fillers. Molding compounds and various device packages based on this powder have been introduced commercially. These packages offer large improvements in thermal performance, comparable to heat spreaders and in some cases, exposed heat slugs: reductions of 25-30% in /spl Theta//sub ja/ and 50% in /spl Theta//sub jc/, respectively are typical. Reliability data, including electrical, thermal, environmental and mechanical properties, measured for QFP and SOIC packages indicate that SCAN-based packages exhibit reliability equivalent to packages molded with standard molding compounds. Perhaps most importantly, these packages may also offer significant cost savings, depending on the specific package type.