Laminar Metal Foam: A Soft and Highly Thermally Conductive Thermal Interface Material with a Reliable Joint for Semiconductor Packaging

2021 ◽  
Author(s):  
Peng Liu ◽  
Yingying Luo ◽  
Jiaman Liu ◽  
Sum Wai Chiang ◽  
Dang Wu ◽  
...  
Keyword(s):  
Metal Foam ◽  
Thermal Interface Material ◽  
Thermal Interface ◽  
Thermally Conductive ◽  
Semiconductor Packaging

Development of High Thermally Conductive Die Attach for TIM Applications

2019 ◽  
Vol 2019 (1) ◽  
pp. 000312-000315
Author(s):  
Maciej Patelka ◽  
Sho Ikeda ◽  
Koji Sasaki ◽  
Hiroki Myodo ◽  
Nortisuka Mizumura
Keyword(s):  
Thermal Conductivity ◽  
High Power ◽  
Thermal Interface Material ◽  
Thermal Interface ◽  
Power Semiconductor ◽  
Die Attach ◽  
Industry Standards ◽  
Thermally Conductive ◽  
Low Modulus ◽  
Thermal Grease

Abstract High power semiconductor applications require a Thermal Interface Die Attach Material with high thermal conductivity to efficiently release the heat generated from these devices. Current Thermal Interface Material solutions such as thermal grease, thermal pads and silicones have been industry standards, however may fall short in performance for high temperature or high-power applications. This presentation will focus on development of a cutting-edge Die Attach Solution for Thermal Interface Management, focusing on Fusion Type epoxy-based Ag adhesive with an extremally low Storage Modulus and the Thermal Conductivity reaching up to 30W/mK, and also Very Low Modulus, Low-Temperature Pressureless Sintered Silver Die Attach with the Thermal Conductivity of 70W/mK.

Characterization of Thermal Contact Resistance in Metal Micro-Textured Thermal Interface Materials Using Electrical Contact Resistance Measurements

2010 ◽  
Vol 297-301 ◽  
pp. 1190-1198 ◽  
Author(s):  
R. Kempers ◽  
A.J. Robinson ◽  
A. Lyons
Keyword(s):  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Electrical Contact ◽  
Applied Pressure ◽  
Thermal Interface Material ◽  
Metal Foil ◽  
Electrical Contact Resistance ◽  
Thermal Interface ◽  
Thermally Conductive

A novel Metal Micro-Textured Thermal Interface Material (MMT-TIM) has been developed to address a number of shortcomings in conventional TIMs. This material consists of a thin metal foil with raised micro-scale features that plastically deform under an applied pressure thereby creating a continuous, thermally conductive, path between the mating surfaces. One of the difficulties in experimentally characterizing MMT-TIMs however, is distinguishing the bulk thermal resistance of the MMT-TIM from the thermal contact resistance that exists where it contacts the test apparatus. Since these materials are highly electrically conductive, this study attempts to employ electrical contact resistance measurements to estimate their thermal contact resistance. Tests using flat silver and gold specimens of known bulk thermal conductivity were used to develop a correlation between electrical and thermal contact resistance. This relationship was then employed to estimate the thermal contact resistance of a prototype silver MMT-TIM and indicates the thermal contact resistance accounts for approximately 10% of the measured thermal contact resistance. A number of issues related to this technique are discussed as well as its future outlook.

Thermal and Mechanical Modeling of Metal Foams for Thermal Interface Application

2016 ◽  
Vol 138 (7) ◽  
Author(s):  
Ninad Trifale ◽  
Eric Nauman ◽  
Kazuaki Yazawa
Keyword(s):  
Thermal Resistance ◽  
Metal Foam ◽  
Electronics Cooling ◽  
Cost Effective ◽  
Metal Foams ◽  
High Porosity ◽  
Pore Density ◽  
Thermal Interface ◽  
Interface Thermal Resistance ◽  
Thermally Conductive

We present a study on the apparent thermal resistance of metal foams as a thermal interface in electronics cooling applications. Metal foams are considered beneficial for several applications due to its significantly large surface area for a given volume. Porous heat sinks made of aluminum foam have been well studied in the past. It is not only cost effective due to the unique production process but also appealing for the theoretical modeling study to determine the performance. Instead of allowing the refrigerant flow through the open cell porous medium, we instead consider the foam as a thermal conductive network for thermal interfaces. The porous structure of metal foams is moderately compliant providing a good contact and a lower thermal resistance. We consider foam filled with stagnant air. The major heat transport is through the metal struts connecting the two interfaces with high thermally conductive paths. We study the effect of both porosity and pore density on the observed thermal resistance. Lower porosity and lower pore density yield smaller bulk thermal resistance but also make the metal foam stiffer. To understand this tradeoff and find the optimum, we developed analytic models to predict intrinsic thermal resistance as well as the contact thermal resistance based on microdeformation at the contact surfaces. The variants of these geometries are also analyzed to achieve an optimum design corresponding to maximum compliance. Experiments are carried out in accordance with ASTM D5470 standard. A thermal resistance between the range 17 and 5 K cm2/W is observed for a 0.125 in. thick foam sample tested over a pressure range of 1–3 MPa. The results verify the calculation based on the model consisting the intrinsic thermal conductivity and the correlation of constriction resistance to the actual area of contact. The area of contact is evaluated analytically as a function of pore size (5–40 PPI), porosity (0.88–0.95), orientation of struts, and the cut plane location of idealized tetrakaidecahedron (TKDH) structure. The model is developed based on assumptions of elastic deformations and TKDH structures which are applicable in the high porosity range of 0.85–0.95. An optimum value of porosity for minimizing the overall interface thermal resistance was determined with the model and experimentally validated.

Development of a Metal Micro-Textured Thermal Interface Material

2009 ◽  
Author(s):  
R. Kempers ◽  
R. Frizzell ◽  
A. Lyons ◽  
A. J. Robinson
Keyword(s):  
Thermal Conductivity ◽  
Applied Pressure ◽  
Solid Particles ◽  
High Thermal Conductivity ◽  
Thermal Interface Material ◽  
Filler Materials ◽  
Mechanical And Thermal Properties ◽  
Metal Foil ◽  
Thermal Interface ◽  
Thermally Conductive

Typical thermal interface materials (TIMs) consist of high thermal conductivity solid particles dispersed in a continuous, low thermal conductivity organic compound. Despite using filler materials of very high thermal conductivity, the effective thermal conductivity of these TIMs is often two orders of magnitude lower than the pure filler materials. In addition, dispensing and flow of the particle-matrix composite results in voids being trapped within the bond. To address these issues, a novel metal micro-textured thermal interface material (MMT-TIM) has been developed. This material consists of a thin metal foil with raised micro-scale features that plastically deform under an applied pressure thereby creating a continuous, thermally conductive, path between the mating surfaces. Numerical tools have been developed that couple the mechanical and thermal properties and behaviour of MMT-TIMs as they undergo large-plastic deformation during assembly. This study presents the modelling approach and predictions of MMT-TIM performance based on these numerical techniques. The predictions show good agreement with experimental results, which were obtained using prototype MMT-TIMs and an advanced TIM characterization facility. Finally, a future outlook for this technology is presented based on these promising initial results.

Impact of thermal interface material on luminous flux curve of InGaAlP low-power light-emitting diodes

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Muna E. Raypah ◽  
Mutharasu Devarajan ◽  
Shahrom Mahmud
Keyword(s):  
Low Power ◽  
Thermal Resistance ◽  
Thermal Management ◽  
Light Output ◽  
Luminous Flux ◽  
Thermal Interface Material ◽  
Junction Temperature ◽  
Thermal Interface ◽  
Content Type ◽  
Thermally Conductive

Purpose One major problem in the lighting industry is the thermal management of the devices. Handling of thermal resistance from solder point to the ambiance of the light-emitting diode (LED) package is linked to the external thermal management that includes a selection of the cooling mode, design of heatsink/substrate and thermal interface material (TIM). Among the significant factors that increase the light output of the of the LED system are efficient substrate and TIM. In this work, the influence of TIM on the luminous flux performance of commercial indium gallium aluminium phosphide (InGaAlP) low-power (LP) LEDs was investigated. Design/methodology/approach One batch of LEDs was mounted directly onto substrates which were glass-reinforced epoxy (FR4) and aluminium-based metal-core printed circuit boards (MCPCBs) with a dielectric layer of different thermal conductivities. Another batch of LEDs was prepared in a similar way, but a layer of TIM was embedded between the LED package and substrate. The TIMs were thermally conductive epoxy (TCE) and thermally conductive adhesive (TCA). The LED parameters were measured by using the integrated system of thermal transient tester (T3Ster) and thermal-radiometric characterization of LEDs at various input currents. Findings With the employment of TIM, the authors found that the LED’s maximum luminous flux was significantly higher than the value mentioned in the LED datasheet, and that a significant reduction in thermal resistance and junction temperature was revealed. The results showed that for a system with low thermal resistance, the maximum luminous flux appeared to occur at a higher power level. It was found that the maximum luminous flux was 24.10, 28.40 and 36.00 lm for the LEDs mounted on the FR4 and two MCPCBs, respectively. After TCA application on the LEDs, the maximum luminous flux values were 32.70, 36.60 and 37.60 lm for the FR4 and MCPCBs, respectively. Moreover, the findings demonstrated that the performance of the LED mounted on the FR4 substrate was more affected by the employment of the TIM than that of MCPCBs. Research limitations/implications One of the major problems in the lighting industry is the thermal management of the device. In many low-power LED applications, the air gap between the two solder pads is not filled up. Heat flow is restricted by the air gap leading to thermal build-up and higher thermal resistance resulting in lower maximum luminous flux. Among the significant factors that increase the light output of the LED system are efficient substrate and TIM. Practical implications The findings in this work can be used as a method to improve thermal management of LP LEDs by applying thermal interface materials that can offer more efficient and brighter LP LEDs. Using aluminium-based substrates can also offer similar benefits. Social implications Users of LP LEDs can benefit from the findings in this work. Brighter automotive lighting (signalling and backlighting) can be achieved, and better automotive lighting can offer better safety for the people on the street, especially during raining and foggy weather. User can also use a lower LED power rating to achieve similar brightness level with LED with higher power rating. Originality/value Better thermal management of commercial LP LEDs was achieved with the employment of thermal interface materials resulting in lower thermal resistance, lower junction temperature and brighter LEDs.

Structural design of multilayer thermally conductive nanofibrillated cellulose hybrid film with electrically insulating and antistatic properties

2018 ◽  
Vol 6 (26) ◽  
pp. 7085-7091 ◽  
Author(s):  
Na Song ◽  
Haidong Pan ◽  
Xiaofei Liang ◽  
Donglei Cao ◽  
Liyi Shi ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Structural Design ◽  
Heat Dissipation ◽  
Hybrid Film ◽  
Nanofibrillated Cellulose ◽  
Thermal Interface Material ◽  
Environment Friendly ◽  
Thermal Interface ◽  
Thermally Conductive

We fabricate a thermally conductive, electrically insulating and environment-friendly composite as a thermal interface material (TIM) with excellent tensile strength for heat dissipation.

scholarly journals Development of High Thermally Conductive Die Attach for TIM Applications

2020 ◽  
Vol 17 (3) ◽  
pp. 106-109
Author(s):  
Maciej Patelka ◽  
Sho Ikeda ◽  
Koji Sasaki ◽  
Hiroki Myodo ◽  
Nortisuka Mizumura
Keyword(s):  
Thermal Conductivity ◽  
High Power ◽  
Thermal Interface Material ◽  
Thermal Interface ◽  
Power Semiconductor ◽  
Die Attach ◽  
Industry Standards ◽  
Thermally Conductive ◽  
Low Modulus ◽  
Thermal Grease

Abstract High-power semiconductor applications require a thermal interface die attach material with high thermal conductivity to efficiently release the heat generated from these devices. Current thermal interface material solutions such as thermal grease, thermal pads, and silicones have been industry standards, however may fall short in performance for high-temperature or high-power applications. This article focuses on development of a cutting-edge die attach solution for thermal interface management, focusing on fusion-type epoxy-based Ag adhesive with an extremely low storage modulus and the thermal conductivity reaching up to 30 W/mK, and also very low-modulus, low-temperature pressureless sintering silver die attach with a thermal conductivity of 70 W/mK.

scholarly journals Graphene–graphite hybrid epoxy composites with controllable workability for thermal management

2019 ◽  
Vol 10 ◽  
pp. 95-104 ◽  
Author(s):  
Idan Levy ◽  
Eyal Merary Wormser ◽  
Maxim Varenik ◽  
Matat Buzaglo ◽  
Roey Nadiv ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Management ◽  
Electronic Device ◽  
Total Concentration ◽  
Hybrid Approach ◽  
Thermal Interface Material ◽  
Thermal Interface ◽  
Thermally Conductive ◽  
Hybrid Polymer Composite ◽  
The One

The substantial heat generation in highly dense electronic devices requires the use of materials tailored to facilitate efficient thermal management. The design of such materials may be based on the loading of thermally conductive fillers into the polymer matrix applied – as a thermal interface material – on the interface between two surfaces to reduce contact resistance. On the one hand, these additives enhance the thermal conductivity of the composite, but on the other hand, they increase the viscosity of the composite and hence impair its workability. This in turn could negatively affect the device–matrix interface. To address this problem, we suggest a tunable composite material comprising a combination of two different carbon-based fillers, graphene nanoplatelets (GNPs) and graphite. By adjusting the GNP:graphite concentration ratio and the total concentration of the fillers, we were able to fine tune the thermal conductivity and the workability of the hybrid polymer composite. To facilitate the optimal design of materials for thermal management, we constructed a ‘concentration–thermal conductivity–viscosity phase diagram’. This hybrid approach thus offers solutions for thermal management applications, providing both finely tuned composite thermal properties and workability. We demonstrate the utility of this approach by fabricating a thermal interface material with tunable workability and testing it in a model electronic device.

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