An Experimental Investigation of the Contribution of Different Carbonaceous Nanomaterials to Thermal Conductance of Thermal Interface Materials

2019 ◽  
Author(s):  
Prashant Singh ◽  
Seul-Yi Lee ◽  
Roop L. Mahajan
Keyword(s):  
Experimental Investigation ◽  
Graphene Oxide ◽  
Thermal Performance ◽  
Morphological Changes ◽  
Thermal Conductance ◽  
Thermal Dissipation ◽  
Rubber Matrix ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Interface Materials

Abstract With the increasing demand for higher performance and progressive miniaturization of electronic packages, power densities and the attendant thermal dissipation requirements are expected to escalate. One of the important strategies to ensure reliable operation at the device and die (chip) levels is the use of Thermal Interface Materials (TIMs) to reduce the thermal resistance between the chip and the heat sink. In this study, we have carried out an experimental investigation to characterize thermal conductance of TIMs composed of commercially available graphene (c-rGO), graphene nanoplatlets (GNPs) of different lateral sizes (5, 15 and 25 μm), and our in-house produced thermally reduced graphene oxide at 600°C (T-rGO-600). These additives were loaded in a silicone rubber matrix where their loading fraction was fixed at 2% by weight. Thermal conductance of the resulting TIMs was determined by measuring heat flow, in steady state, through a TIM sandwiched between two metal blocks. The thermal conductance values representing the combined resistance of the composite material and the contact resistances between the TIM and the metal blocks were measured at different heat flux levels across the TIM. The results show that the thermal conductance values were independent of the heat load across the TIM as well as the TIM temperature. Further, a detailed investigation of the surface functionality and structural properties has revealed that the in-house produced T-rGO-600 has superior thermal conductance when compared to the above-mentioned carbonaceous nanomaterials, which are considered as potential candidates for enhancing thermal performance of TIMs. The data demonstrates that this result is attributable to the formation of the surface functional groups and the associated morphological changes during the reduction of graphene oxide to the T-rGO-600. Among the different GNPs tested, the GNP-15 exhibited superior thermal performance compared to the GNP-5 and GNP-25 samples.

Manufacturability trade-offs of bare-die FCBGA package using thin or core-less substrate

2017 ◽  
Vol 2017 (DPC) ◽  
pp. 1-26
Author(s):  
Ankita Verma ◽  
Baqar Tabrez ◽  
Lam Duong ◽  
Martin Wuest
Keyword(s):  
Thermal Performance ◽  
Flip Chip ◽  
Material Selection ◽  
Full Range ◽  
Thermal Dissipation ◽  
Thermal Interface Materials ◽  
Assembly Process ◽  
Thermal Interface ◽  
Performance Requirement ◽  
Interface Materials

With the increasing demand for thinner packages and higher electrical & thermal performance requirement bare-die packaging is an inevitable trend that is growing. The assembly process for manufacturing of bare die in thin or core-less substrate FCBGA packages can be challenging especially considering the effects of substrate warpage during flip chip bonding and the excessive warpage of the flip chip package. We are evaluating the manufacturing risks during bare-die FCBGA package assembly to eliminate package warpage failures using experimental techniques and improve the functional performance of the flip chip package. Various substrate & under fill materials were tested for package warpage values for warpage-free control in the full range of temperature variation. Die designs at 28nm and 40nm process nodes are extremely complex in order to achieve the highest electrical & thermal performance requirement. Die design constraints on advanced process nodes necessitate increased thermal dissipation requirements thereby requiring investigation of thermal solutions utilizing thermal interface materials (TIM) with heat-sink. The interaction of such thermal solutions with the bare die packages is evaluated using various trial and error for material selection, experimental and simulation techniques to improve the assembly process. This study also focuses on selection of thermal interface materials [TIMs] and heat sinks which have considerable impact on die integrity during package assembly and/or during process of removal for failure analysis.

Characterizing Bulk Thermal Conductivity and Interface Contact Resistance Effects of Thermal Interface Materials in Electronic Cooling Applications

2003 ◽  
Author(s):  
Vadim Gektin ◽  
Sai Ankireddi ◽  
Jim Jones ◽  
Stan Pecavar ◽  
Paul Hundt
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Contact Resistance ◽  
Thermal Performance ◽  
Electronic Cooling ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Interface Contact ◽  
Interface Materials ◽  
Bulk Thermal Conductivity

Thermal Interface Materials (TIMs) are used as thermally conducting media to carry away the heat dissipated by an energy source (e.g. active circuitry on a silicon die). Thermal properties of these interface materials, specified on vendor datasheets, are obtained under conditions that rarely, if at all, represent real life environment. As such, they do not accurately portray the material thermal performance during a field operation. Furthermore, a thermal engineer has no a priori knowledge of how large, in addition to the bulk thermal resistance, the interface contact resistances are, and, hence, how much each influences the cooling strategy. In view of these issues, there exists a need for these materials/interfaces to be characterized experimentally through a series of controlled tests before starting on a thermal design. In this study we present one such characterization for a candidate thermal interface material used in an electronic cooling application. In a controlled test environment, package junction-to-case, Rjc, resistance measurements were obtained for various bondline thicknesses (BLTs) of an interface material over a range of die sizes. These measurements were then curve-fitted to obtain numerical models for the measured thermal resistance for a given die size. Based on the BLT and the associated thermal resistance, the bulk thermal conductivity of the TIM and the interface contact resistance were determined, using the approach described in the paper. The results of this study permit sensitivity analyses of BLT and its effect on thermal performance for future applications, and provide the ability to extrapolate the results obtained for the given die size to a different die size. The suggested methodology presents a readily adaptable approach for the characterization of TIMs and interface/contact resistances in the industry.

Mechanical Insertion and Reliability Testing of Thermal Interface Materials for Semiconductor Test and Burn-in Applications

2018 ◽  
Vol 2018 (1) ◽  
pp. 000613-000618
Author(s):  
Dave Saums ◽  
Tim Jensen ◽  
Carol Gowans ◽  
Seth Homer ◽  
Ron Hunadi
Keyword(s):  
Thermal Performance ◽  
Mechanical Performance ◽  
Device Under Test ◽  
Thermal Interface Materials ◽  
Reliability Testing ◽  
Mechanical Reliability ◽  
Thermal Interface ◽  
Cycling Test ◽  
Semiconductor Test ◽  
Interface Materials

Abstract Semiconductor test and burn-in requirements for thermal interface materials (TIMs) are challenging, with difficult mechanical reliability requirements that are not found in other types of applications for these materials. To demonstrate the ability of certain newly-developed TIMs to not only provide suitable thermal performance for the device under test and meet these mechanical requirements, a contact cycling test has been devised in three phases for evaluating TIM mechanical performance and durability.

Thermal and Mechanical Properties of Silicone Thermal Interface Materials With Varying Cross-Link Densities

2005 ◽  
Author(s):  
Arun Gowda ◽  
Annita Zhong ◽  
Sandeep Tonapi ◽  
Kaustubh Nagarkar ◽  
K. Srihari
Keyword(s):  
Mechanical Properties ◽  
Thermal Performance ◽  
Cross Linking ◽  
Thermal Interface Materials ◽  
Material System ◽  
Thermal And Mechanical Properties ◽  
Thermal Impedance ◽  
Operating Life ◽  
Thermal Interface ◽  
Interface Materials

Thermal Interface Materials (TIMs) play a key role in the thermal management of microelectronics by providing a path of low thermal impedance between the heat generating devices and the heat dissipating components (heat spreader/sink). In addition, TIMs need to reliably maintain this low thermal resistance path throughout the operating life of the device. Currently, several different TIM material solutions are employed to dissipate heat away from semiconductor devices. Thermal greases, adhesives, gels, pads, and phase change materials are among these material solutions. Each material system has its own advantages and associated application space. While thermal greases offer excellent thermal performance, their uncured state makes them susceptible to pump-out and other degradation mechanisms. On the other hand, adhesives offer structural support but offer a higher heat resistance path. Gels are designed to provide a level of cross-linking to allow the thermal performance of greases and prevent premature degradation. However, the degree of crosslinking can have a significant effect of the behavior of gels. In this research, TIMs with varying cross-linking densities are studied and their thermal and mechanical properties reported. The base resin systems and fillers were maintained constant, while slight compositional alternations were made to induce different degrees of cross-linking.

Vertically Aligned Multi-Walled Carbon Nanotube Arrays as Thermal Interface Materials and Measurement Technique

2005 ◽  
Author(s):  
Tao Tong ◽  
Yang Zhao ◽  
Lance Delzeit ◽  
Ali Kashani ◽  
Arun Majumdar ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Glass Plate ◽  
Thermal Conductance ◽  
Thermal Interface Materials ◽  
Optical Pump ◽  
Thermal Interface ◽  
Multi Walled Carbon Nanotube ◽  
Vertically Aligned ◽  
The Difference ◽  
Interface Materials

State-of-the-art thermal interface materials are briefly reviewed with an emphasis on the emerging trend of using carbon nanotubes to increase interface thermal performance. Vertically aligned multi-walled carbon nanotube (MWCNT) arrays were grown and applied as thermal interfacial enhancing materials. It is expected that the highly thermally conductive channels directly bridging the mating surfaces would significantly enhance the interface thermal conductance. We extended the all-optical pump and probe phase sensitive transient thermo-reflectance (PSTTR) method and used it to measure the interfacial properties of a three-layer sample of a vertically aligned MWCNT array grown on silicon (Si) substrate dry adhered to a glass plate. The dominant thermal resistance is identified as the dry adhered MWCNT-glass interface with a thermal conductance of ~5.9 × 104 W/m2·K, compared with MWCNT-Si interface of almost two orders of magnitude higher. Tentative explanations on the difference in the two interfaces and ways for future improvements are provided. The PSTTR measurement principle and issues are also discussed in the context.

Durability of Low Melt Alloys as Thermal Interface Materials

2016 ◽  
Vol 138 (1) ◽  
Author(s):  
Chandan K. Roy ◽  
Sushil Bhavnani ◽  
Michael C. Hamilton ◽  
R. Wayne Johnson ◽  
Roy W. Knight ◽  
...  
Keyword(s):  
Thermal Performance ◽  
Performance Testing ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
High Performing ◽  
Accelerated Life ◽  
Significant Performance ◽  
Interface Materials ◽  
Temperature Aging

This study investigates the reliability of low melt alloys (LMAs) containing gallium (Ga), indium (In), bismuth (Bi), and tin (Sn) for the application as Thermal interface materials (TIMs). The analysis described herein involved the in situ thermal performance of the LMAs as well as performance evaluation after accelerated life cycle testing, which included high temperature aging at 130 °C and thermal cycling from −40 °C to 80 °C. Three alloys (75.5Ga & 24.5In, 100Ga, and 51In, 32.5Bi & 16.5Sn) were chosen for testing the thermal performance. Testing methodologies used follow ASTM D5470 protocols and the performance of LMAs is compared with some high-performing commercially available TIMs. Results show that LMAs can offer extremely low (<0.01 cm2 °C/W) thermal resistance compared to any commercial TIMs. The LMA–substrate interactions were explored using different surface treatments (copper and tungsten). Measurements show that depending on the substrate–alloy combinations, the proposed alloys survive 1500 hrs of aging at 130 °C and 1000 cycles from −40 °C to 80 °C without significant performance degradation. The obtained results indicate the LMAs are very efficient as TIMs.

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