20點直播｜北京大學教授王瑋講述微系統熱管理

直播時間：2024年9月20日（周五）20:00-21:30

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北京時間2024年9月20日晚八點，iCANX Talks 第204期邀請到了北京大學王瑋教授作為主講嘉賓，香港科技大學助理教授鄭琪野、北京大學助理教授楊林也將進行分享！北京大學助理研究員教授張弛、北京科技大學教授邱琳擔任研討嘉賓，北京大學張海霞教授擔任主持人。這將是一場匯聚頂尖學者的盛會，共同探討前沿科技與學術挑戰！更多精彩，敬請期待！

【嘉賓介紹】

Wei Wang

?北京大學

Thermal Management for Microsystem

【Abstract】

With the rapid development of integrated circuit technology, especially the introduction of advanced packaging techniques such as 3D integration, chip integration density and power consumption continue to increase. At the same time, a large number of low thermal conductivity dielectric materials are widely used in chips and their packaging structures, making chip heat dissipation increasingly difficult. Thermal management has become a bottleneck issue that cannot be ignored in the field of microsystem. This presentation discusses the demand and development status of thermal management technology in advanced packaging, and reports the recent research achievements of the presenter’s lab in the field of thermal management for microsystem, such as embedded microfluidic cooling technology.

隨著集成電路技術的快速發展，特別是3D集成等先進封裝技術的引入，芯片集成密度和功耗不斷增加。與此同時，大量的低導熱介質材料被廣泛應用于芯片及其封裝結構中，使得芯片散熱越來越困難。熱管理已成為微系統領域不可忽視的瓶頸問題。報告討論了先進封裝中熱管理技術的需求和發展現狀，并介紹了報告人實驗室在微系統熱管理領域的最新研究成果，如基于等效熱導率模型的快速熱仿真算法、嵌入式微流體冷卻技術。

【BIOGRAPHY】

Prof. Wei Wang is the deputy dean of School of Integrated Circuits, Peking University and the director of the National Key Laboratory of Science and Technology on Micro/ Nano Fabrication. He received his B.S. in Thermal engineering from University of Shanghai for Science and Technology (USST, 1999) and the Ph.D. in Thermal Engineering from Tsinghua University (2005). He was a Visiting Professor in UC Davis (with Prof. Tingrui Pan) from 2007-2008 and Caltech (with Prof. YC Tai) from 2014-2015. His research focus on Parylene MEMS, clinical micro/nanosystem, and thermal management of 3D microsystem. He has published over 200 peer-reviewed articles, over 50 presentations with over 15 invited presentations, and 50 patents pending or granted. He is the Associated Editor of Microfluidics and Nanofluidics, Microsystems & Nanoengineering, and has served/ is serving on organizing committees for several international conferences, including IEEE MEMS’2015 and ‘2016, Transducers’2019, and 2021 etc.

王瑋， 2005年博士畢業于清華大學航天航空學院，師從過增元院士。長江學者特聘教授、國家卓越青年科學基金獲得者，微米/納米加工技術國家級科技創新團隊學術帶頭人。2005年加入北京大學，現任北京大學集成電路學院副院長、微米納米加工技術全國重點實驗室主任。目前擔任微米納米技術學會副秘書長、國家集成電路標準委員會委員、特種元器件標準委員會委員（微系統專項組組長），Microfluidics and Nanofluidics副主編、Microsystems & Nanoengineering等期刊編委，IEEE MEMS、Transducers、ICEPT、CSTIC、EDTM等領域系列重要國際會議技術委員會委員。長期從事微米納米加工技術，特別是基于硅通孔（TSV）的三維集成與芯粒集成前沿技術研究，以及微納流控技術研究。發表領域重要期刊和國際會議論文170余篇，授權、申請發明專利及軟件著作權50余項，包括美國授權專利2項；獲遼寧省科技進步一等獎、中電科科技進步三等獎、日內瓦發明展特別嘉許金獎等獎勵，受邀在包括IEEE Sensors等20余個國際會議上作邀請報告。

Qiye Zheng

香港科技大學

Novel nanoscale thermal metrologies for semiconductor microelectronics

【ABSTRACT】

Thermal management challenges in microelectronics and energy technologies necessitate advanced thermal metrologies and materials. On the one hand, as feature sizes shrink toward the nanoscale in current and emerging semiconductor devices, thermal bottlenecks have emerged as performance limitations due to the high, non-uniform power densities over the past decades. Nanoscale thermometry for temperature mapping is crucial to improve chip-level thermal design and study non-diffusive transport phenomena. For diverse energy technologies, on the other hand, rapid screening of material candidates demands high-throughput characterization.Firstly, I will present our development of a novel electron-beam (e-beam) Reflection Electron Elastic Energy Thermometry (REEET) to address the need for nanoscale thermometry. REEET leverages the Doppler broadening of quasi-elastically scattered electrons in reflection electron energy loss spectroscopy to quantify the mean atomic kinetic energy and thus the local phonon temperature within the 5 nm e-beam probe area. Our calibration experiments compared with first-principles modeling confirmed the physics of REEET, showing a relative temperature sensitivity of ~0.09%/K for light elements like carbon and silicon between 300-600 K. We used REEET for far-field temperature mapping of 300-400 nm nanostructured graphitic thin films and a 250-nm diameter multiwalled carbon nanotube under Joule heating. Local hotspots were visualized in-situ with 20-60 nm resolution and a temperature standard deviation of ~35 K. Suppressed in-plane/axial k’s were observed via numerical modeling, ascribed to size effects and interface scattering. REEET overcomes the optical diffraction-limits and scanning probe complexity to enable flexible characterization of nanoscale temperature fields without the sample thinning requirement in TEM.Secondly, I will introduce our development of high-throughput photothermal metrology for materials screening leveraging structured illumination with thermal imaging (SI-TI). Traditional contact thermal measurements have challenges with throughput and the lack of spatially resolvable property mapping, while laser methods require serial raster scanning to achieve property mapping and frequently need mirror smooth sample surfaces. In comparison, SI-TI method is demonstrated to (1) enable paralleled measurement of multiple regions and samples without raster scanning; (2) allow dynamic adjustment of the heating pattern in software to optimize the measurement sensitivity for anisotropic materials; and (3) tolerate rough (~3 μm) and scratched sample surfaces, via measurements of dense and porous materials such as mica and 3D printed thermoelectric thick films. This highlights SI-TI as a new avenue in adaptivity and throughput for thermal characterization of diverse materials.

微電子和能源技術領域的熱管理挑戰需要先進的熱計量和材料。一方面,隨著當前和新興半導體器件特征大小的不斷縮小到納米尺寸,在過去幾十年中,由于局部非均勻高功率密度產生的熱瓶頸已經成為性能限制。新型非接觸納米測溫技術的研究可以在改進芯片級熱設計和研究非擴散傳輸現象方面起到關鍵作用。另一方面,為各種能源技術快速篩選材料候選人需要高通量表征。首先,我將介紹基于電子束反射電子彈性散射(REEET)的新型納米測溫技術。REEET利用在反射電子能量損失譜中的準彈性散射電子的多普勒寬度來定量平均原子動能和5nm電子束探針區域內的局部聲子溫度。我們進行的校準實驗與第一原理計算的比較證實了REEET的機理,在300-600K之間,如碳和硅等輕元素的相對溫度靈敏度約為0.09%/K。通過REEET對300-400nm的結構石墨薄膜和250nm直徑多壁碳納管在焦耳加熱條件下的遠場溫度分布圖，展示了REEET的高空間分辨率20-60nm和約35K的溫度標準偏差。通過數值模擬驗證了實驗觀測，將碳納米材料中熱導降低歸因于尺寸效應和界面散射。REEET克服了光學衍射限制和掃描探針復雜性,能夠更靈活地表征納米尺寸的溫度場,而無需TEM樣品磨薄。其次,我將介紹我們開發的利用結構光照明與熱成像(SI-TI)實現高通量光熱計量的技術。傳統的接觸熱測量存在通量低和缺乏空間分辨率性能等挑戰,而激光方法需要逐點掃描來實現性能映射,且常需要鏡面光滑的表面處理。SI-TI方法證明可以(1)實現多個區域和樣本的并行測量,無需掃描;(2)通過軟件動態調整加熱圖案來優化各向異性材料的測量靈敜度;(3)容忍較粗糙(約3um)和劃傷樣本表面,通過對密實和多孔材料例如閃石和3D打印熱電厚膜的測量。這突出了SI-TI在靈活度和通量方面的新途徑,用于各種材料的熱特征表征。

【BIOGRAPHY】

Dr. Qiye Zheng is current an Assistant Professor of Mechanical and Aerospace Engineering at The Hong Kong University of Science and Technology. He worked at UC Berkeley and Lawrence Berkeley National Lab from 2019-2022 after obtaining his PhD in 2017 and a 1-year postdoc in Materials Science and Engineering from the University of Illinois at Urbana-Champaign. His current research interests include nanoscale heat transfer, non-invasive thermal wave characterization, switchable thermal materials, dynamic thermal insulation, and thermal metrology. He has published 32 papers in prestigious journals such as Science, Applied Physics Review, Advanced Functional Materials, and Applied Energy with 2200+ citations and a h-index of 18. He is the recipient of NSFC Excellent Young Scientists Fund (Overseas, 2022). He serves as an independent reviewer for 47 distinct journals including Physical Review Letter, Advanced Functional Materials, and Nano Letter, a Topic Editor for Frontiers in Mechanical Engineering, and a Topical Advisory Panel member of the journal Crystals. He also served as session chair and poster judge for various conferences.

鄭琪野博士于2022年起任香港科技大學機械與航空航天系助理教授。2012年于北京大學物理學院取得理學學士學位，2017 年獲得美國伊利諾伊大學香檳分校材料科學工程博士學位并進行了一年的博士后研究，師從美國科學院院院士David Cahill教授，加入港科大前任加州大學伯克利分校博士后研究員，合作導師是美國工程院院士Ravi Prasher教授和UC Berkeley機械系主任Chris Dames教授。長期從事傳熱表征測量和功能材料相關的研究，在新型熱測量技術、材料表征、和傳熱仿真方面積累了豐富的經驗，近幾年以通訊、第一或共同第一作者在 Science, Applied Physics Review，International Journal of Heat and Mass Transfer， Advanced Functional Materials等期刊發表學術論文，相關 SCI 文章32篇，美國專利一項， Web of Science 引用1800余次， h 因子20。在新型光學高通量熱測量技術，電子束納米測溫技術以及熱功能材料方面取得了一定成果。其研究受EurekAlert, Electronics Weekly, ScienceDaily, Physics World等媒體報道。目前擔任美國ASME K9委員會成員，擔任47種SCI 期刊審稿人，受邀為Physical Review Letter, Nano Letter, Advanced Functional Material ，Applied Energy等47種期刊審稿210余次，多次在中國和韓國進行受邀報告。

Lin Yang

北京大學

Cross-Scale Heat Dissipation Mechanisms in 3D Integrated Chips

【ABSTRACT】

As Moores Law advances to the nanometer scale, 3D integration technology has become critical for its continuation. However, the heat dissipation issues caused by high-density interconnect structures have emerged as a major challenge restricting the development of advanced chips. In this presentation, I will introduce our research on the thermal transport mechanisms in 3D integrated chips. The report covers three key areas: First, we have developed precise measurement techniques spanning the angstrom to micron scales, establishing a model that links thermal conductivity in silicon under strain gradients to local strain and atomic-scale phonon spectra, revealing the anomalous effects of non-uniform stress on thermal performance. Second, we have developed an ultra-high-precision thermal testing platform to study abnormal thermal conductivity phenomena in ultra-thin nanostructures. Finally, we investigated the impact of electron-phonon scattering on thermal conductivity in doped semiconductors by regulating carrier concentration through phase change, providing theoretical support for chip heat dissipation optimization.

隨著摩爾定律推進至納米節點，三維集成技術成為延續摩爾定律的關鍵。然而，高密度互連結構帶來的散熱問題，已成為限制先進芯片發展的主要挑戰。在本報告中，我將介紹我們對三維集成芯片中熱傳輸機制的研究。報告的主要內容包括三個方面：首先，我們研發了覆蓋埃米至微米尺度的精密測量技術，建立應變梯度下硅材料導熱性能與局域應變、原子尺度聲子譜之間的關聯模型，揭示非均勻應力對導熱性能的異常影響。其次，我們開發了超高精度熱測試平臺，研究超薄納米結構中的異常導熱現象。最后，我們通過相變調控載流子濃度，研究摻雜半導體中電子-聲子散射對導熱的影響機制，為芯片散熱優化提供理論支持。

【BIOGRAPHY】

Lin Yang is an Assistant Professor in the School of Engineering at Peking University. He received his bachelor’s degree in 2014 from Xian Jiaotong University (Qian Xuesen Class) and his Ph.D. in Mechanical Engineering from Vanderbilt University in 2019. From 2019 to 2022, he conducted postdoctoral research at Lawrence Berkeley National Laboratory, before joining the Department of Advanced Manufacturing and Robotics at Peking Universitys School of Engineering in 2022. He was selected for the 2021 National High-Level Overseas Young Talent Program. Dr. Yangs research focuses on micro- and nanoscale heat transfer, chip thermal management, functional thermal devices, high-temperature thermal energy storage, and phonon noise reduction in quantum computing. His work has significant implications for thermal management in 3D integrated chips, low-carbon energy, post-Moore era quantum chip thermal design, and national defense. Over the past five years, he has published more than ten high-impact SCI papers. His research, as the first or corresponding author, has appeared in prestigious international journals such as Nature, Nature Nanotechnology, Science Advances, Nature Communications, and Nano Letters. His work has been invited for presentation at numerous international academic conferences, and his papers have been recognized as “2020 PCCP Hot Articles” and “2019 Nanoscale Hot Articles.”

楊林，北京大學工學院助理教授，于2014年在西安交通大學（錢學森班）獲學士學位，2019年獲美國范德堡大學機械工程專業博士學位，2019年至2022年在勞倫斯伯克利國家實驗室進行博士后研究，于2022年加入北京大學工學院先進制造與機器人系。長期從事于微納尺度傳熱，芯片散熱，功能性熱器件，高溫熱能存儲和量子計算中聲子噪音消除等方面的研究。取得的一系列成果對三維集成芯片熱管理，低碳能源，后摩爾時代量子芯片熱設計和國防等領域有重要意義。近五年來，發表高水平SCI論文十余篇，研究成果以第一作者或通訊作者發表在Nature，Nature Nanotechnology ，Science Advances，Nature Communications，Nano Letters等國際高水平期刊。相關研究成果多次在國際學術會議上以特邀形式報告，發表文章獲得“2020 PCCP 年度熱門文章精選”，“2019 Nanoscale 年度熱門文章精選”。