US EPA

2185899 

Book/Book Chapter 

Design for enhanced solder joint reliability of integrated passives device under board level drop test and thermal cycling test 

Tee, TY; Ng, HS; Zhong, ZW 

2003 

Electronics Packaging Technology Conference Proceedings 

210-216 

WOS:000189435300039 

Integrated Passives Device (IPD) is an advanced substrate with embedded passives. The device is mounted to board with lead-free solder joints. Using a common full 3D geometry model, both drop impact and thermal cycling fatigue simulations are performed for an integrated design for board level solder joint reliability. The model includes detailed pad geometry and realistic shape of solder balls. For drop test simulation, IPD on board is susceptible to solder joint failures, induced by a combination of PCB bending and mechanical shock during impact. The dynamic model established has close values of peak acceleration and impact duration as the desired impact pulse. The critical solder joint is observed to be along the outer row of solder balls in the PCB length direction, and may fail either along the solder/PCB pad interface or solder/IPD pad interface. Interfacial failure of solder joint under drop impact is mainly due to peeling stress. As for thermal cycling fatigue simulation, a modified Darveaux's approach with non-linear viscoplastic analysis of lead-free solder joints is applied. Temperature-dependent material properties are considered for the packaging materials used. The fatigue model is first solved to obtain the strain energy density, and then the characteristic life is calculated. For the designs studied, the critical solder joint is observed at the outermost corner solder joint, and fails along the solder/IPD pad interface. Solder joint failure during the thermal cycling test is mainly in shear mode. In this paper, there are eight types of IPD designs considered for both drop test and thermal cycling test with variations in IPD shape, IPD size, IPD thickness, IPD material properties, solder material, solder ball layout, PCB size, and PCB material properties. Some design parameters may not have the same effects on both drop test and thermal cycling test. Therefore, compromise in final IPD design is required, depending on end application and customer requirement.