Thermal Management in 3D Homogeneous NoC Systems Using Optimized Placement of Liquid Microchannels

Three-dimensional stacked Network-on-Chip (3D-NoC) systems are proposed to replace the traditional shared bus architecture to make interconnections possible inside a System-on-Chip (SoC). 3D-NoC is gaining popularity among designers due to scalability, higher bandwidth, fault tolerance, and reliability. However, the stacking of multiple dies leads to severe thermal problems due to increasing power density, the miniature of the circuits and placement of functional units on top of each other. Due to low thermal resistance and larger thermal resistance of air as a coolant, traditional air cooling approaches are unable to dissipate heat from the 3D stacked systems. Liquid microchannel cooling has heat removal capability from the die. However, adding liquid channels on a chip is an expensive process. We justify the use of liquid channel thermal management as the 3D chip for our experimental work is many-core system with large number NoCs and processing elements. In this paper, liquid microchannels are added on the chip, and their placement is optimized using the genetic algorithm. The heat transfer model is formulated by a combination of forced convection and thermal resistance network to predict the temperature profile across the 3D chip. The thermal management by optimized placement of liquid microchannels approach will enable 3D NoC systems to integrate a higher number of functional units and enhance the performance and throughput.