*********************************
There is now a CONTENT FREEZE for Mercury while we switch to a new platform. It began on Friday, March 10 at 6pm and will end on Wednesday, March 15 at noon. No new content can be created during this time, but all material in the system as of the beginning of the freeze will be migrated to the new platform, including users and groups. Functionally the new site is identical to the old one. webteam@gatech.edu
*********************************
Atlanta, GA | Posted: May 18, 2018
Summary Sentence:
What is new in packaging @ Georgia Tech? New Innovations in Thermal Management of 2.5D and 3D Packages
Full Summary:
No summary paragraph submitted.
Figure 1. New innovations in thermal management of high-density glass packages.
Figure 2. (a) schematic of glass interposer package with copper structures and vapor chamber integrated in PCB
Figure 2. (b) junction-to-board thermal resistance in 4 different study cases; and 
Figure 2. (c) thermal resistance of PCB integrated with vapor chamber (total thickness: ~ 1 mm) vs. copper plated PCB (total thickness: ~ 1 mm)
Figure 3. Schematic of directly grown Cu heat spreaders onto backside of IC chip
Figure 4. All-Cu die-attach joints formed after densification of patterned nano-Cu foam films
Figure 5. (a) Depiction of a power module that is mounted directly on the cooling system, utilizing gradient, and 
Figure 5. (b) composite metal foamsPower input and thermal outputs are two of the biggest challenges in all electronics. The need for thermal management arises because of the power supplied to the small ICs with highest electrical resistance in any system, according to the well-known Joule’s Law. Mobile products are trending to higher and higher performance, requiring thermal management in thinnest form factors and at lowest cost. In high-performance computing, increasing bandwidth requirements keep driving the need for 2.5D and 3D integrations with highest I/O densities and shortest interconnect lengths. But these integrations, particularly the 3D logic-memory package integration, presents new thermal management challenges that have yet to be fully addressed. In parallel, advances in electric cars enabled by the fast adoption of wide bandgap devices are driving the need for higher thermal and power densities, which requires novel integrated and miniaturized system-level cooling solutions.
Glass packaging is emerging as an ideal next-generation packaging substrate in 2.5D and 3D package architectures in high-performance computing and 5G communications because of its many advantages including ultra-high electrical resistivity, low loss, high thermal and dimensional stabilities and large-area panel manufacturing for low cost. Two package architectures are being concurrently pursued: substrate-based and embedding-based, both in large panels. However, glass has a relatively low thermal conductivity (~1 W/m∙K) compared to silicon (~150 W/m∙K), which may aggravate thermal challenges in some applications.
The Georgia Tech-led team is comprehensively addressing the above challenges with advances in all aspects of thermal management at chip and system levels, as shown in Figure 1, with: a) copper through-via structures and two-phase heat-spreaders, b) Near-zero and low-resistance thermal interfaces and c) external cooling with miniaturized single and two-phase cold plates.
The first step in solving the thermal challenge of glass substrates is to increase their thermal conductivity overall and at selective spots through inclusions of metalized copper structures.
(a) schematic of glass interposer package with copper structures and vapor chamber integrated in PCB;
(b) junction-to-board thermal resistance in 4 different study cases; and
(c) thermal resistance of PCB integrated with vapor chamber (total thickness: ~ 1 mm) vs. copper plated PCB (total thickness: ~ 1 mm)
(a) thermal resistance of PCB integrated with vapor chamber (total thickness: ~ 1 mm) vs. copper plated PCB (total thickness: ~ 1 mm).
(b) composite metal foams.
About the Authors
Dr. Sangbeom Cho was a PhD student in PRC, and advised by Prof. Yogendra Joshi and Prof.Tummala. His research focus is on thermal modeling, design and characterization. He is currently with Qualcomm and can be reached at scho84@gatech.edu
Nithin Nedumthakady is a PhD student in Prof. Rao Tummala’s group, and being mentored by Dr. Venky Sundaram and Dr. Vanessa Smet. His research focus is on thermal management in embedded modules, nnedumthakady3@gatech.edu.
Kashyap Mohan is a PhD student in Prof. Rao Tummala’s group, and being mentored by Dr. Vanessa Smet. His research focus is on nano-copper die-attach materials, kmohan9@gatech.edu.
Justin Broughton is a PhD student in PRC, and advised by Prof. Yogendra Joshi and Prof Tummala. His research focus is on thermal modeling, design and characterization, justin.d.broughton@gatech.edu
Dr. Venky Sundaram is a Research Professor in Prof. Tummala’s group, and the Deputy Director of the Center, vs24@mail.gatech.edu.
Dr. Vanessa Smet is a Research Professor in Prof. Tummala’s group, and the Program Manager for high-power packaging, thermal management and interconnections and assembly areas, vanessa.smet@prc.gatech.edu.
Prof. Yogendra Joshi is an Endowed Chair Professor in the ME Department, Georgia Tech. yogendra.joshi@me.gatech.edu.
Prof. Rao Tummala is the Joseph M. Pettit Chair Professor in ECE and MSE, and the Director of Georgia Tech’s 3D Systems Packaging Research Center (GT PRC), rao.tummala@ece.gatech.edu.
