Scanning the Special Issue on On-Chip Thermal Engineering

2004

As electronic components continue to decrease in size and increase in power, thermal management becomes more important. Devices such as heat sinks and fans can help alleviate thermal problems, but add cost and manufactUling complexity to devices. More intimate knowledge of how a component behaves can allow companies to better determine the viability of a design and reduce over building.

2014

Embedded systems are used in safety critical areas such as automotive electronics and medical applications. These safety critical applications impose strict requirements on reliability, performance, low power and testability of the underlying VLSI circuits. The VLSI circuits operate very often at high temperature, which has negative impact on reliability, performance, power-efficiency and testability with silicon technology scaling. Several thermal impacts on VLSI circuits and their related challenges are discussed. This paper presents also a few emerging techniques that take temperature into account in the design and test processes. There are number of embedded computers controlling virtually all devices and systems in a huge spectrum of application areas including aerospace, manufacturing, chemical processes, healthcare care, automotive, transportation, telecommunication, and consumer appliances. Many of these systems are safety-critical, such as automotive electronics and medical...

IEEE Transactions on Components and Packaging Technologies, 2000

A novel cooling device fully built in silicon technology is presented. The new concept developed in this work consists in micromachining the bottom side of the circuit wafer in order to embed heat sinking microchannels directly into the silicon material. These microchannels are then sealed, by a direct wafer bonding procedure, with another silicon wafer where microchannels and inlet-outlet nozzles are micromachined too. A cooling fluid (water) is then forced through the array of channel to convey heat outside the chip. Such a configuration presents the advantages to provide a significant reduction of the cooler overall dimensions, to reduce the number of the involved materials and to be compatible with integrated circuits fabrication procedures. In this study analytical tools were used in order to get a global evaluation of all the thermal resistances characteristic of such devices. Using these adequate analytic models with appropriate approximations, a global optimization procedure was then applied and led to the definition of he optimum dimensions of the silicon micro heat sink. The realization procedure was then carried out in a clean room environment. First experimental characterization results obtained from the earlier prototypes demonstrated that the thermal properties of this silicon-based cooling device are satisfactory and can be reasonably compared to those of commercially available copper micro heat sinking components.

In all circuit networks, there is a need to balance the amount of heat generated by each circuit component with the power density. Managing the heat generated by electronic elements have always been one of the greatest tasks in any electronic design. Many thermal management techniques of microprocessor have been proposed and implemented for different systems. It was observed that the issue of microprocessor thermal-management needs to be addressed from the basis, that is, the application of the floor planning technique. Also, there is the need to balance the performance measure with the thermal technique in such a way that one needs not to be compromised for another. This paper identifies some of the thermal management techniques proposed by different authors, the gaps and the likely prospects.

Process technology scaling, poor supply voltage scaling and the resultant exponential increase in power density have made temperature a first-class design constraint in today's microprocessors. An interesting question in the context of thermal management and multi-core architectures is about the correct size granularity of thermal management. It is known that the silicon substrate acts as a spatial low-pass filter for temperature. This means that if blocks with very high power density are small enough (for e.g., if they are below a "cut-off " size), they do not cause hot spots. This paper investigates this phenomenon analytically and presents a discussion through three microarchitectural examples. First is a thermal study of a many-core architecture which illustrates the thermal benefit of many small cores as opposed to a few large cores. This study also explores the effect of local vs. global thermal management. Second is an investigation of whether high aspect ratio sub-blocks such as cache lines can become hot spots due to pathological code behaviour. Third is an exploration of thermal sensor accuracy as a function of the number of sensors and a characterization of two sensor interpolation schemes as a means to reduce sensor errors.

2019

The main task of this project is the development of a modular heat exchanger to dissipate a TDP (Total Dissipated Power) of 140-180 W on a microprocessor. This exchanger should be able to dissipate the reference target TDP respecting the maximum operating temperatures (above these temperatures the CPU goes into thermal throttle) and the longevity temperatures (lower than the thermal throttle temperatures). This result should be achieved while providing product versatility (based on the concept to adapt the exchanger to each socket), acceptable noise, acceptable size and cost. The heart of the project is the design of a suitable fin surface to protect processors with high TDP. In this case, a significant increase in fan speed and in the size of the finned body is inevitable. In this way, an increase in the heat removal is obtained by larger airflow rate (high number of revolutions of the fan) and the large exchange surface. Considering the impact of these changes, the design of the e...

IEEE Transactions on Components and Packaging Technologies, 2002

The presentations made, as well as the discussions, in the panels at the workshop, Thermal Challenges in Next Generation Electronic Systems (THERMES), are summarized in this paper. The panels dealt with diverse topics including thermal management roadmaps, microscale cooling systems, numerical modeling from the component to system levels, hardware for future high performance and internet computing architectures, and transport issues in the manufacturing of electronic packages. The focus of the panels was to identify barriers to further progress in each area that require the attention of the research community.

Periodica Polytechnica Electrical Engineering and Computer Science

Thanks to the System-on-Package technology (SoP) the integration of different elements into a single package was enabled. However, from the thermal point of view the heat removal path in modern packaging technologies (FCBGA) goes through several layers of thermal interface material (TIM) that together with the package material create a relatively high thermal resistance which may lead to elevated chip temperature which causes functional error or other malfunctions. In our concept, we overcome this problem by creating integrated microfluidic channel based heat sink structures that can be used for cooling the high heat dissipation semiconductor devices (e.g.: processors, high power transistor or concentrated solar cells). These microchannel cooling assemblies can be integrated into the backside of the substrate of the semiconductor devices or into the system assemblies in SoP technology. In addition to the realization of the novel CMOS compatible microscale cooling device we have deve...

2013 IEEE/ACM International Conference on Computer-Aided Design (ICCAD), 2013

Two-phase liquid cooling of computer chips via microchannels etched directly on silicon dies is a potential long-term solution to enable continued integration of high-performance multiprocessors. Two-phase cooling refers to the heat removal via evaporation of a refrigerant flowing inside a heat sink. While possessing superior cooling properties, largescale use of this technology in the industry is limited by the lack of thermal modeling tools that can accurately predict temperatures in a two-phase cooled IC. In this paper, we propose STEAM, a new compact thermal model for 2D/3D ICs with two-phase cooling via silicon microchannels. The accuracy of the STEAM model is validated against measurements from a real two-phase cooled IC test stack reported previously in literature. Temperatures were predicted with an average error as low as 10.2% for uniform heat fluxes and 6.9% for hotspots. Finally, the STEAM model is applied to a realistic 3D multiprocessor system-on-chip (3D MP-SoC) with two-phase cooling to simulate IC temperatures and the refrigerant pumping power, demonstrating the applicability of STEAM in the early-stage design of near-future high-performance computers with two-phase cooling.

Je-Young Chang received his B.S. and M.S. degrees from the Seoul National University in South Korea and his Ph.D. degree from University of Texas at Arlington, all in mechanical engineering. He worked at Penn State University for three years as a research associate before joining Intel in 2000. He has worked on many aspects of advanced cooling technologies, including twophase immersion cooling, single/two-phase microchannel cooling, corrosion reliability of liquid cooling systems, heat pipes, TIMs, heat exchangers, etc. He has 19 issued/pending US patents, and more than 60 articles in archival journals, conference proceedings and Intel internal publications.