New generation thin plastic packages delivers higher levels of power and reliability performance for power IC devices

As advances in device scaling continue, the challenges in miniaturized surface mount plastic package developments include heat dissipation and reliability problems. Therefore, the advancement of power packaging technology is expected to have an influence on the pace of power electronic systems progress through the next millennium. At Siliconix, several new generations of power surface mount packages have emerged for power semiconductor devices and ICs. The thermal design and characteristics of one of these new packages, a 48-lead TQFP, are discussed. Special leadframe properties and thermal design guidelines which provide quantitative understanding for package temperature distribution and key thermal variables are summarized. Stress and qualification test results indicate that this package has an excellent reliability performance when compared to the current industry standard requirements. An improvement by a factor of 6 in die attach shear strength has been achieved. In addition, C-SAM analysis of parts exposed to preconditioning and HAST tests revealed that these new packages have very high cracking and moisture penetration resistance characteristics. This enhancement in package thermal performance and reliability has been achieved with no increase in manufacturing cost or change in package outline.