Electrical characteristics of fine pitch flip chip solder joints fabricated using low temperature solders

Design and Implementation of a Highly Integrated Dual Active Bridge Microconverter

“…8 shows a Cadence simulation result of the efficiency of one elementary CMOS inverter leg for different rates of the mean load current while switching at 1 MHz and V DD = 5 V. Its parameters are given in Table II. Bump resistances R BUMP and interconnections tracks are also taken into account for each power I/O pad of the inverter leg assuming an elementary series resistance of 5 mΩ [26]. Simulation results show that 97% efficiency can be achieved over a wide current range even for higher power levels; the main limitation in this case being the heat removal capability of the extra losses.…”

A computational damage mechanics model for thermomigration

“…In a finite element mesh, all interfaces have 100% perfect adhesion. However, in actual solder joints, it is well known that even in a good joint, the effective contact area is no more than 50% of the gross interface area (Un-Byoung and Young-Ho, 2004;Nah and Suh, 2005). Usually the percentage of interface actually in contact can be as low as 10%.…”

Interconnections for Additively Manufactured Hybridized Printed Electronics in Harsh Environments

“…Common low temperature solders consist of tin (Sn) with varying compositions of bismuth (Bi) or indium (In). Bi soldering alloys tend to have higher strength but reduced ductility and susceptibility to thermal aging [52][53][54][55][56][57][58]. On the other hand, In is a much softer alloy, which reduces its strength, yet it has greater ductility.…”

“…On the other hand, In is a much softer alloy, which reduces its strength, yet it has greater ductility. Alloys of In are also not as susceptible to thermal aging but it is significantly more expensive than Bi [53,57,59]. A small addition of silver (Ag) with typical weight composition less than 1% in Bi and In solder alloys can improve the reduced properties in both alloys [52,55,57,58,60].…”