RELIABILITY DEVELOPMENT AND QUALIFICATION OF A LOW-COST PQFP-BASED MCM

In Motorola's experience with commercial MCM customers, cost and size reduction are the largest driving factors for interest in MCM's, Speed and other performance factors are of secondary interest. Development and qualification can add significantly to the total cost of an MCM, s o in addition to the normal desire to provide reliable products, the c ost of doing so has gained increased importance, Motorola has identifi ed three key factors in providing cost-effective MCM's: leverage singl e chip package experience, qualify MCM product families (package types ), and use only qualified silicon devices in MCM products. This paper describes application of the three key factors to the reliability qual ification of the 28-mm MCML(TM) Series package,(1) a PQFP- (Plastic Qu ad Flat Pack) based MCM, An initial reliability evaluation was perform ed to investigate reliability issues, As a result of the initial evalu ation, changes were made to assembly processes and materials, The MCM was then submitted to a suite of reliability stresses selected to eval uate mechanical, thermo-mechanical, moisture, and longevity performanc e, The MCM passed electrical and visual (SAT, or Scanning Acoustic Tom ography) reliability requirements for all stresses, and performed well in extended stress tests as well, A procedure is in place to help ins ure high reliability for additional products in the 28-mm PQFP-based M CM package.