On the Way to Zero Defect of Plastic-Encapsulated Electronic Power Devices—Part I: Metallization

Abstract

Concerning thermomechanically induced failures, such as metal line deformation and passivation cracks, there is a practicable way to achieve the zero-defect limit of plasticencapsulated power devices. This limit can be reached by evaluating the influence of the major components involved and, consequently, by selecting the appropriate materials and measures. On the other hand, the interdependence between all components must always be kept in mind, i.e., chip and package have to be regarded as an entity. An important finding was that applying simply one improvement step will not necessarily lead to the desired goal. Only the implementation of all improvement steps considering their interdependence is the key for the perfect overall system chip and package. In Part I of this series of papers, the yield stress of the power metallization is shown to play a crucial role for the generation of metal deformation and passivation cracks. Understanding the ratcheting mechanism led to the development of a new layered metallization material with a distinctly increased yield stress, resulting in a considerably reduced failure generation.

Towards zero-defect manufacturing (ZDM)—a data mining approach

“…It concluded that best results in improving product quality are attained when requirements aimed at strengthening technological discipline and improving production planning and organization are adhered to rigorously and consistently. Alpernand his colleagues [10][11][12] attempted zero-defect product of plastic-encapsulated electronic power devices and concluded that the ambitious goal to reach the zero-defect frontier is achievable.…”

Microscopic stress simulation of non-planar chip technologies

“…For metals, plasticity was also included [10]. Mold compound is visco-elastic and the visco-elasticity data was implemented in the modeling using Prony series [4,11]. Layers with different material properties were combined to one layer with equivalent material properties [4,12].…”

“…Mold compound is visco-elastic and the visco-elasticity data was implemented in the modeling using Prony series [4,11]. Layers with different material properties were combined to one layer with equivalent material properties [4,12]. The properties of other materials used in the model are mostly from our available material models and unavailable material data were characterized.…”

“…Precise geometry data at this corner region was included in the simulation. The rest was simplified using equivalent material models [4,12] and advantages of symmetry were used and the resulted finite element model is shown in Fig. 10.…”

“…Finite element simulation is a cost and time effective approach and is often performed to address these reliability issues. Tremendous growth in computer power has made it possible to perform large scale simulations, and hence, plenty of work has been reported in this field [3,4].…”