Collaborative Research: EAGER: Novel thermal interface material with Cu nanowire array

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

Collaborative Proposals Proposal Numbers: #1140953 / #1140121 P.I.'s: Costas Grigoropoulos / Renkun Chen Institution: University of California-Berkeley / University of California-San Diego Thermal interface materials play a critical role in thermal management of electronic devices. Current materials, such as greases and solders would be insufficient for cooling the devices with increasingly higher power dissipation level. The objective of this research is to develop a high performance thermal interface material based on copper nanowire array. The new material will have one order of magnitude lower thermal contact resistance compared to the existing ones. To achieve this goal, vertically aligned, dense arrays of single crystalline copper nanowires with well-controlled diameters, spacing and packing density will be synthesized by electroplating through porous anodic alumina membranes. Fundamental studies on mechanical, thermal and electrical properties of individual nanowires will be carried out by using micro-fabricated devices. Interfacial and bulk thermal resistances of copper nanowire arrays will be characterized using a sensitive transient thermo-reflectance technique. Intellectual Merit: Copper nanowires simultaneously possess two important features that make them a unique candidate for high performance thermal interface materials: high thermal conductivity and high mechanical compliance. Because of the high thermal conductivity and the high packing density of approximately 50%, copper nanowire array has a lower thermal contact resistance compared to the state of the art thermal interface materials. Moreover, the large aspect ratio of the nanowires (> 200:1) makes them highly compliant when subjected to thermal stress, hence the high thermal performance can be retained after thermal cycling. The proposed topics of investigation will advance the understanding of mechanical and electro-thermal properties of copper nanowires pertaining to thermal packaging applications, both individually and collectively as an array, and will lead to the development of a new class of thermal interface materials with superior thermal and mechanical properties. Broader Impacts: Thermal interface material is one of the key thermal packaging components that are highly demanded by microelectronic industry pursuing increasingly higher clock speed. The proposed copper nanowires based interfaces could become a disruptive enabling technology for developing electronic devices with higher performance, hence can potentially make a tremendous societal impact. Educational and outreach activities will be tightly integrated into the program. By developing new curriculum and recruiting undergraduate students into the research, the program will educate next generation thermal engineers who will be motivated by fascinating nanosciences and the grand technological challenges faced by our society. The proposed outreach programs will leverage the efforts of both the Berkeley and UCSD campuses for promoting diversities, and will benefit K-12 and under-represented students.