Effect of Thermal Interface Materials on Maximum Chip Temperature in Heat Spreader System for a Bare Chip with High Heat Flux

2002 ◽  
Vol 2002.55 (0) ◽  
pp. 205-206
Author(s):  
Toshio TOMIMURA
Keyword(s):  
Heat Flux ◽  
High Heat ◽  
Thermal Interface Materials ◽  
High Heat Flux ◽  
Heat Spreader ◽  
Thermal Interface ◽  
Chip Temperature ◽  
Interface Materials

Integrated Vapor Chamber Heat Spreader for Power Module Applications

2017 ◽  
Author(s):  
Clayton L. Hose ◽  
Dimeji Ibitayo ◽  
Lauren M. Boteler ◽  
Jens Weyant ◽  
Bradley Richard
Keyword(s):  
Heat Flux ◽  
Thermal Resistance ◽  
Power Electronics ◽  
Coefficient Of Thermal Expansion ◽  
High Heat ◽  
Heat Fluxes ◽  
High Heat Flux ◽  
Vapor Chamber ◽  
Power Module ◽  
Heat Spreader

This work presents a demonstration of a coefficient of thermal expansion (CTE) matched, high heat flux vapor chamber directly integrated onto the backside of a direct bond copper (DBC) substrate to improve heat spreading and reduce thermal resistance of power electronics modules. Typical vapor chambers are designed to operate at heat fluxes > 25 W/cm2 with overall thermal resistances < 0.20 °C/W. Due to the rising demands for increased thermal performance in high power electronics modules, this vapor chamber has been designed as a passive, drop-in replacement for a standard heat spreader. In order to operate with device heat fluxes >500 W/cm2 while maintaining low thermal resistance, a planar vapor chamber is positioned onto the backside of the power substrate, which incorporates a specially designed wick directly beneath the active heat dissipating components to balance liquid return and vapor mass flow. In addition to the high heat flux capability, the vapor chamber is designed to be CTE matched to reduce thermally induced stresses. Modeling results showed effective thermal conductivities of up to 950 W/m-K, which is 5 times better than standard copper-molybdenum (CuMo) heat spreaders. Experimental results show a 43°C reduction in device temperature compared to a standard solid CuMo heat spreader at a heat flux of 520 W/cm2.

Surface Chemistry and Characteristics Based Model for the Thermal Contact Resistance of Fluidic Interstitial Thermal Interface Materials

2001 ◽  
Vol 123 (5) ◽  
pp. 969-975 ◽  
Author(s):  
Ravi S. Prasher
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Thermal Interface Materials ◽  
Heat Spreader ◽  
Thermal Interface ◽  
Thermal Solution ◽  
Interface Materials

Microprocessor powers are increasing at a phenomenal rate, which requires very small thermal resistance between the die (chip) and the ambient, if the current economical methods of conduction and convection cooling are to be utilized. A typical thermal solution in flip chip technology utilizes two levels of thermal interface materials: between the die and the heat spreader, and between the heat spreader and the heat sink. Phase change materials and thermal greases are among the most prominent interstitial thermal interface materials (TIM) used in electronic packaging. These TIMs are typically polymeric matrix loaded with highly conducting filler particles. The dwindling thermal budget has necessitated a better understanding of the thermal resistance of each component of the thermal solution. Thermal conductivity of these particle-laden materials is better understood than their contact resistance. A careful review of the literature reveals the lack of analytical models for the prediction of contact resistance of these types of interstitial materials, which possess fluidic properties. This paper introduces an analytical model for the thermal contact resistance of these types of interstitial materials. This model is compared with the experimental data obtained on the contact resistance of these TIMs. The model, which depends on parameters such as, surface tension, contact angle, thermal conductivity, roughness and pressure matches very well with the experimental data at low pressures and is still within the error bars at higher pressures.

scholarly journals Development of Nanostructured-based Composites as Advanced Thermal Interface Materials

2020 ◽  
Vol 5 (1) ◽  
Keyword(s):  
Boron Nitride ◽  
Thermal Management ◽  
Filler Material ◽  
Filler Materials ◽  
Thermal Interface Materials ◽  
High Heat Flux ◽  
Thermal Interface ◽  
Air Gaps ◽  
Boron Arsenide ◽  
Interface Materials

Thermal management is one of the most critical issues in electronics due to increasing power densities. This problem is getting even worse for small and sophisticated devices due to air gaps present between the heat source and heat sink. Thermal interface materials (TIM) are used to reduce the air gaps and significantly increase the heat transfer capability of the system. A high-thermal-performance, cost-effective and reliable TIM would be needed to dissipate the generated heat, which could enable significant reductions in weight, volume and cost of the thermal management system. In this study a number of different nanostructured materials are reviewed for potential use as a filler material in our effort to develop advanced TIM composite. Some of the candidate filler materials considered is Carbon Nanotubes, Graphene and Few Layer Graphene (FLG), Boron Nitride Nanotubes (BNNT) and Boron Nitride Nanomesh (BNNM) and Boron Arsenide (BAs). Objective is to identify composition of boron arsenide as filler in polymer-nanostructured material composite TIM for high heat flux applications. In order to design boron-arsenide-based TIM composite with enhanced effective thermal conductivity, a number of metallic and nonmetallic base-filler material composites are considered with varying filler fractions. Empirical mixture models based on effective medium theories (EMT) are evaluated for estimating effective conductivity of the two-component boron arsenide-filler composite TIM structure.

Nano-Structured Two-Phase Heat Spreader for Cooling Ultra-High Heat Flux Sources

2010 ◽  
Author(s):  
Mitsuo Hashimoto ◽  
Hiroto Kasai ◽  
Kazuma Usami ◽  
Hiroyuki Ryoson ◽  
Kazuaki Yazawa ◽  
...  
Keyword(s):  
Heat Flux ◽  
Copper Powder ◽  
High Heat ◽  
High Heat Flux ◽  
Vapor Chamber ◽  
Heat Spreader ◽  
Two Phase ◽  
Evaporator Temperature ◽  
Sintered Copper ◽  
Multi Walled Carbon Nanotubes

A two-phase heat spreader has been developed for cooling high heat flux sources in high-power lasers, high-intensity light-emitting diodes, and semiconductor power devices. The heat spreader targets the passive cooling of heat sources with fluxes greater than 5 W/mm2 without requiring any active power consumption for the thermal solution. The prototype vapor chamber consists of an evaporator plate, a condenser plate and an adiabatic section, with water as the phase-change fluid. The custom-designed high heat flux source is composed of a platinum resistive heating pattern and a temperature sensor on an aluminum nitride substrate which is soldered to the outside of the evaporator. Experiments were performed with several different microstructures as evaporator surfaces under varying heat loads. The first microstructure investigated, a screen mesh, dissipated 2 W/mm2 of heat load but with an unacceptably high evaporator temperature. A sintered copper powder microstructure with particles of 50 μm mean diameter supported 8.5 W/mm2 without dryout. Four sets of particle diameters and different thicknesses for the sintered copper powder evaporators were tested. Additionally, some of the sintered structures were coated with multi-walled carbon nanotubes (CNT) that were rendered hydrophilic. Such nano-structured evaporators successfully showed a further reduction in thermal resistance of the vapor chamber.

A two-phase heat spreader for cooling high heat flux sources

2010 ◽  
Author(s):  
Mitsuo Hashimoto ◽  
Hiroto Kasai ◽  
Yuichi Ishida ◽  
Hiroyuki Ryoson ◽  
Kazuaki Yazawa ◽  
...  
Keyword(s):  
Heat Flux ◽  
High Heat ◽  
High Heat Flux ◽  
Heat Spreader ◽  
Two Phase

Development of Micro/Nano Engineered Wick-Based Passive Heat Spreaders for Thermal Management of High Power Electronic Devices

2011 ◽  
Author(s):  
David H. Altman ◽  
Joseph R. Wasniewski ◽  
Mark T. North ◽  
Sungwon S. Kim ◽  
Timothy S. Fisher
Keyword(s):  
Heat Flux ◽  
Thermal Resistance ◽  
Thermal Performance ◽  
High Heat ◽  
Test Facility ◽  
Great Promise ◽  
High Heat Flux ◽  
Vapor Chamber ◽  
Heat Spreader

Spreading of high-flux electronics heat is a critical part of any packaging design. This need is particularly profound in advanced devices where the dissipated heat fluxes have been driven well over 100W/cm2. To address this challenge, researchers at Raytheon, Thermacore and Purdue are engaged in the development and characterization of a low resistance, coefficient of thermal expansion (CTE)-matched multi-chip vapor chamber heat spreader, which utilizes capillary driven two-phase heat transport. The vapor chamber technology under development overcomes the limitations of state-of-the-art approaches by combining scaled-down sintered Cu powder and nanostructured materials in the vapor chamber wick to achieve low thermal resistance. Cu-coated vertically aligned carbon nanotubes is the nanostructure of choice in this development. Unique design and construction techniques are employed to achieve CTE-matching with a variety of device and packaging materials in a low-profile form-factor. This paper describes the materials, design, construction and characterization of these vapor chambers. Results from experiments conducted using a unique high-heat flux capable 1DSS test facility are presented, exploring the effects of various microscopic wick configurations, CNT-functionalizations and fluid charges on thermal performance. The impacts of evaporator wick patterning, CNT evaporator functionalization and CNT condenser functionalization on performance are assessed and compared to monolithic Cu wick configurations. Thermal performance is explained as a function of applied heat flux and temperature through the identification of dominant component thermal resistances and heat transfer mechanisms. Finally, thermal performance results are compared to an equivalent solid conductor heat spreader, demonstrating a >40% reduction in thermal resistance. These results indicate great promise for the use of such novel vapor chamber technology in thickness-constrained high heat flux device packaging applications.

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