Advanced Micro-Channel Vapor Chamber for Cooling High Power Processors

Abstract

After the introduction of Pentium™ processor in 1993, the trend of the processor performance and power consumption have been increased significantly each year. Heat dissipation has been increased but in contrast the size of die on the processor has been reduced or remained the same size due to nano-size circuit technology and thus the heat flux is critically high. The heat flux was about 10–15 W/cm2 in the year 2000 and had reached 100 W/cm2 in 2006. The processor’s die surface where the heat is generated is usually small, approximately 1 cm2. For effective cooling should required least temperature gradient between the heat source and radiating components. The best known devices for effective heat transfer or heat spreading with lowest thermal resistance is heat pipe and vapor chamber. Basically, heat pipe and vapor chamber are an evacuated and sealed container which contains a small quantity of working fluid which is water. When one side of the container is heated, causing the liquid to vaporize and the vapor to move to the cold side and condensed. Since the latent heat of evaporation is large, considerable quantities of heat can be transported with a very small temperature difference from end to end. The 2-phase heat transfer device has excellent heat spreading and heat transfer characteristics, is the key element in thermal management challenge of ever power-increasing processors. In this paper, authors presented case designs using vapor chamber for cooling computer processors. Proposed ideas of using micro-channel vapor chamber for heat spreading to replace the traditional metal plate heat spreader. Also included in the paper are ideas and data that showed performance improvement of heat spreading devices.