Studies of the effect of an interfacial layer on interfacial reaction and diffusion kinetics in Cu-In based liquid phase sintered composites for high performance thermal management materials
EMSL Project ID
44754
Abstract
This proposal aims to (1) systematically study the elemental diffusion profiles across the interface in Cu-In composites above and below the melting point of In, (2) measure the interfacial reaction rates and study the interfacial intermetallic morphology under liquid-phase sintering and selected thermal treatment conditions, and (3) develop a kinetics model based on interfacial diffusion and reaction to deduce the interfacial microstructure and the effects of either an electroless-deposited 50-200nm Au layer or a 2nm atomic-layer deposited TiN layer. In combination with earlier models showing the relationship between microstructure and macroscopic properties, this model may be used to predict the microstructure, as well as properties of the composite. To meet the demands of thermal interface materials (TIM) with very high thermal conductivity and microelectronic chip-to-package interconnect (IC) materials with high current carrying capacity, a new composite material architecture, comprising particles of a high melting phase (e.g. Cu), surrounded by a matrix of a low melting phase (e.g. In), is being developed at WSU in collaboration with Intel Corporation. This composite solder microstructure, produced by liquid phase sintering (LPS), yields composite solders with thermal and electrical conductivities which are much higher than those available currently, along with the high shear compliance necessary for joining components with disparate thermal expansion properties. The conductivity of this new solder is ~3 times larger than the state-of-the-art In based TIMs, and 30 times larger than that of current used polymer based TIMs. These composites are lead-free metallic materials that can be recycled, and will potentially replace the lead containing solders. The environment friendly nature of these materials is aligned with the roadmap of EMSL.
In addition to TIM and IC applications for electronics, this material architecture is also of importance for thermal management applications for cooling of data centers, where it may be used as high performance TIMs, or as phase-change materials (PCMs) for thermal energy storage for subsequent recovery. The high heat of fusion of metals relative to polymers (which are typically used for low temperature thermal storage) allow these metallic PCMs to store much greater energy on a unit volume basis, whereas the liquid is self-contained within the solid skeletal structure due to surface tension, obviating the need for a container. Thus, these materials can have a wide range of thermal applications relevant to the DOE.
Project Details
Project type
Exploratory Research
Start Date
2011-10-25
End Date
2012-10-28
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Liu J. 2013. Liquid Phase Sintered Composite Solders for Next Generation Thermal Interface Applications . Pacific Northwest National Laboratory, Richland, WA.