Saw singulation characterization on high profile multi chip module packages with thick leadframe

Abstract

Increasing demand for Multi Chip Module (MCM) Power devices in a Quad Flat Non-leaded (QFN) package outline drives the development of the LFCSPs-P (Lead Frame Chip Scale Package-saw-Power). Multi Chip Module offers host benefit including performance improvements such as shorter interconnect lengths between dies, lower power supply inductance and lower off-chip driver. Besides, it can reduce the manufacturing cost and increase the utility of programmable systems [1]. Compared to the leaded package with similar body sizes and lead counts, QFN offers far superior thermal performance and provides excellent electrical characteristics [2]. Package designers used nominal thickness of standard Cu-Alloy leadframe and standard package height meant for power packages with soft solder die attach and heavy Al wire bonding to enhance heat dissipation capability other than the heat sinks. Map type design is used to enhance productivity by maximizing the device density. Singulation is achieved by sawing through the molded leadframe channels with diamond type blades that separated the arrays rows and columns [2]. However, the combination of ductile and brittle material in the same sawing process creates real challenges in term of sawing quality, blade life and throughput. Experiments were carried out and its results show that integration of the blade type, parameters, methodology and other external features give the maximum result for the said challenges © 2004 IEEE.