Enhanced power supply structure with new mesh wiring and electroless plated shunt line and assembly-stress-relaxation structure

In a recent LSI, IR drop on power supply lines is a significant problem for high speed operation, along with an increase of power consumption. In addition, relaxing external stresses during assembly processes is also a serious issue, because more fragile low-k materials are applied to interlayer dielectric films. In this paper, we have developed new structures without adding global interconnect layers. Against the IR drop issue, we have developed 2 different structures. The first structure is the new mesh wiring structure and we have successfully reduced IR drop by 20%. The second structure is the electroless plated shunt line structure and we have successfully obtained reduction in resistance of power supply lines by 38%. To the issue of relaxing stresses, we have succeeded in reducing an assembly stress to 7% with electroless plating. These results indicate that superior structure of global layers can be realized without an increase in chip cost.