Thermal and Structural Analysis of a PLCC Device for Surface Mount Processes

Abstract

Industy is concerned with reliability questions for surface mounted Plastic Encapsulated Chip Carrier (PLCC) devices and various aspects of the encapsulation and mounting process have been studied from a thermal and structural point of view. This paper reports on the results of a two-dimensional Finite Element Analysis (FEA) of a representative cross section of a typical PLCC undergoing surface mount soldering conditions. Results are presented for thermal and structural analyses of the numerical model for both a vapor phase and an infrared soldering process. The analyses show the thermal gradients resulting from the thermal processes in soldering and provides an understanding of the stress distribution in a PLCC during these processes. The thermal results indicate that temperature gradients within the PLCC do not appear to be severe during either process. The stress results confirm the importance of the stress-free reference temperature for the encapsulation material. The effect of some key process and device conditions is also discussed.