Solder Fatigue Problems in Power Packages

Packaging for power semiconductors based on the 3D printing technology Selective Laser Melting

“…The area filling factor of the proposed package will be less than that of the packages proposed in [3], [4] and [5], even with an optimized SLM process. This increases the thermal resistance of the package.…”

“…Moreover, the concept makes use of a structured geometry to decouple the thermal expansion of the different materials. This effect has already been used decades ago by the so called "structured copper" concept [3], [4], and also has been used to a certain degree in the more recent work [5]. The structured copper concept consists of a strain buffer layer realized by pliable copper fibers.…”

Thermal analysis of high power modules

“…A 144 mm2 die is large, and the CTE mismatch between the die and the leadframes in the thick film and IMS technologies could be a serious problem. This problem does not exist to the same extent in DBC since the ceramic is more closely matched to the CTE of Si than is copper [3,4].…”

“…As the materials undergo temperature variation, they expand and contract at different rates which stresses the interface between the layers and can cause interface deterioration (e.g. cracking of solder layers or wire debonding) [2][3][4]. Chemical degradation processes such as dendrite growth and impurity migration are accelerated with increasing temperature, so keeping the absolute temperature of the device low, as well as minimizing the temperature changes to which it is subject is important.…”

Estimation of thermal resistance distributions for die-attach testing in microelectronics

“…There have been several experimental studies on defect detection through die-attach materials, but they generally provide qualitative information about the location of the defects and not the spatial distribution of the thermal resistance. X-ray radiation [3] and ultrasonic scanning [3] have been employed to test large samples. Infrared thermography has been widely used as a temperature measurement method for non-destructive testing generally not related to an identification process of the thermal resistance distribution [4,5].…”