Manufacturability and reliability of non-halogenated molding compounds

In an effort to answer the global call for "Green Technology", On Semiconductor Philippines Inc., has evaluated and qualified molding encapsulant (green molding compounds, GMCs) which do not contain the conventional halogenated flame-retardant. In this study, the tested resin formulations which are based on biphenyl, ortho-cresol novolac and/or dicyclopentadienyl epoxies contain either magnesium hydroxide or phosphorous as flame-retardant. Thermogravimetric analysis revealed higher thermal stability of these GMCs as compared to their halogenated counterparts. Adhesion of some of the GMCs to Ni/Pd/Au-plated leadframes was found to be stronger than adhesion of the halogenated molding compounds. Process parameters for molding of GMCs and non-GMCs into SOIC (small outline integrated chip) and TSSOP (thin shrunk small outline package) were comparable. Test samples passed the normal reliability tests conducted for analog devices. The more stringent oil immersion test at 260 degreesC has qualified the phosphorous-containing biphenyl-based epoxy resin for TSSOP and the magnesium hydroxide-based GMC for the SOIC. This paper reports the results of the characterization, the evaluation and qualification study conducted for the different GMCs.