面向功率器件封装的银包铜亚微米颗粒的制备及封装性能研究

随着现代电子行业的飞速发展，电子功率器件正朝着小型化和高功率化方向迅速演进。这一趋势不仅对功率器件的设计与制造提出了更高的挑战，也对其封装材料提出了新的要求，如高热稳定性、高击穿电压以及高温服役能力等。为满足高功率器件严苛的服役需求，金属烧结技术已逐步取代传统锡焊技术，成为高功率器件芯片粘接的首选封装技术，尤其是通过银（Ag）或铜（Cu）颗粒的烧结技术，实现了“低温烧结、高温服役”的需求。然而，鉴于银的高成本和铜的易氧化性，近年来，融合了这两种材料优点且具有抗氧化外壳的银包铜（Cu@Ag）核壳结构颗粒因其成本效益而受到广泛关注。基于此，本文深入研究了银包铜（Cu@Ag）核壳结构颗粒的可控制备、结构表征及封装性能，研究内容概述如下：

首先，对不同类型的商业银包铜粉进行了系统的微观形貌和热学表征。其次，以商业银包铜粉为填料，甘油与乙二醇的复配溶剂为有机载体，配制了银包铜烧结焊膏，并通过田口实验方法确定了其最佳烧结工艺。然而，所得烧结接头的平均剪切强度仅为24.6 MPa，未达到期望的应用水平，表明商业银包铜粉末难以满足高性能烧结焊膏的开发需求。

通过湿化学还原法，以商业铜粉为模板，乙二胺四乙酸根为络合剂，硝酸银为银源，成功制备了银包铜亚微米颗粒，并系统探究了络合剂、还原剂、银前驱体用量等因素对产物结构和形貌的影响。所制备的银包铜核壳亚微米颗粒表现出良好抗氧化性，即使在空气中存放一个月也无明显氧化。此外，基于这些银包铜颗粒配制的烧结焊膏在300°C、10 MPa条件下烧结10 min后，其接头强度可达41 MPa，与已报道的烧结银膏的性能相当。

最后，基于弹塑性模型的有限元分析方法，详细探讨了温度循环（TC）和功率循环（PC）过程中功率器件烧结铜层的应力应变变化，并系统研究了芯片的形状、尺寸和材料对器件可靠性的影响。研究结果表明，在温度和功率循环下，对于不同尺寸的芯片，尺寸越小的芯片其烧结铜层在仿真中受到的应力越大；而对于面积相同但形状不同的芯片，正方形芯片的烧结铜层受到的应力最小。这一发现有望为电力器件可靠性寿命的定性及定量评估提供有力支持。

[1] YANG G, WANG P, LIU Y, et al. Effect of Ag coating on the oxidation resistance, sintering properties, and migration resistance of Cu particles[J/OL]. Journal of Alloys and Compounds, 2022, 923: 166271.
[2] HANG C, TIAN Y, ZHANG R, et al. Phase transformation and grain orientation of Cu–Sn intermetallic compounds during low temperature bonding process[J/OL]. Journal of Materials Science: Materials in Electronics, 2013, 24(10): 3905-3913.
[3] LI Z, LI M, XIAO Y, et al. Ultrarapid formation of homogeneous Cu6Sn5 and Cu3Sn intermetallic compound joints at room temperature using ultrasonic waves.[J]. Ultrasonics sonochemistry, 2014, 21 3: 924-929.
[4] CHIDAMBARAM V, HATTEL J, HALD J. Design of lead-free candidate alloys for high-temperature soldering based on the Au–Sn system[J/OL]. Materials & Design, 2010, 31(10): 4638-4645.
[5] ROUSSEL P, AZEMAR J. Technology, industry and market trends in WBG power module packaging[C/OL]//CIPS 2014; 8th International Conference on Integrated Power Electronics Systems. 2014: 1-3
[2024-03-19].
[6] YIN L, MESCHTER S J, SINGLER T J. Wetting in the Au–Sn System[J/OL]. Acta Materialia, 2004, 52(10): 2873-2888.
[7] LEE J B, HWANG H Y, RHEE M W. Reliability Investigation of Cu/In TLP Bonding[J/OL]. Journal of Electronic Materials, 2015, 44(1): 435-441.
[8] 陈民铀, 高兵, 杨帆, 等. 基于电-热-机械应力多物理场的IGBT焊料层健康状态研究[J]. 电工技术学报, 2015, 30(20): 9.
[9] LIN H. 2.3 Market and Technology Trends in WBG Materials for Power Electronics Applications[C/OL]. 2015
[2024-03-19].
[10] 石小龙. Cu/In体系低温瞬态液相键合工艺及其机理的研究[D]. 苏州大学.
[11] LEE W W, NGUYEN L T, SELVADURAY G S. Solder joint fatigue models: review and applicability to chip scale packages[J/OL]. Microelectronics Reliability, 2000, 40: 231-244.
[12] KANG N, NA H S, KIM S J, et al. Alloy design of Zn–Al–Cu solder for ultra high temperatures[J/OL]. Journal of Alloys and Compounds, 2009, 467(1): 246-250.
[13] YOON J W, BAE S, LEE B S, et al. Bonding of power device to ceramic substrate using Sn-coated Cu micro paste for high-temperature applications[J/OL]. Applied Surface Science, 2020, 515: 146060.
[14] LI J F, AGYAKWA P A, JOHNSON C M. Kinetics of Ag3Sn growth in Ag–Sn–Ag system during transient liquid phase soldering process[J/OL]. Acta Materialia, 2010, 58(9): 3429-3443.
[15] LAI Y T, LIU C Y. Study of wetting reaction between eutectic AuSn and Au foil[J/OL]. Journal of Electronic Materials, 2006, 35(1): 28-34.
[16] 李在元, 刘海英, 宫泮伟, 等. 纳米铜粉研究进展[J]. 有色矿冶, 2004(3): 40-43.
[17] 耿新玲, 苏正涛. 液相法制备纳米铜粉的研究[J/OL]. 应用化工, 2005(10): 28-30.
[18] BROUGHTON J, SMET V, TUMMALA R R, et al. Review of Thermal Packaging Technologies for Automotive Power Electronics for Traction Purposes[J/OL]. Journal of Electronic Packaging, 2018, 140(040801)
[2024-03-19].
[19] 楚广, 唐永建, 刘伟, 等. 纳米铜粉的制备及其应用[J]. 金属功能材料, 2005(3): 18-21.
[20] 刘成雁, 李在元, 翟玉春, 等. 纳米铜粉研制的新进展[J]. 中国有色冶金, 2005(6): 21-24+56.
[21] H. -J. HUANG, X. WU, M. -B. ZHOU, et al. A highly reliable die bonding approach for high power devices by low temperature pressureless sintering using a novel Cu nanoparticle paste[C/OL]//2020 IEEE 70th Electronic Components and Technology Conference (ECTC). 2020: 1697-1702.
[22] MA H, SUHLING J C. A review of mechanical properties of lead-free solders for electronic packaging[J/OL]. Journal of Materials Science, 2009, 44(5): 1141-1158.
[23] HSIAO C H, KUNG W T, SONG J M, et al. Development of Cu-Ag pastes for high temperature sustainable bonding[J/OL]. Materials Science and Engineering: A, 2017, 684: 500-509.
[24] LI J, YU X, SHI T, et al. Depressing of CuCu bonding temperature by composting Cu nanoparticle paste with Ag nanoparticles[J/OL]. Journal of Alloys and Compounds, 2017, 709: 700-707.
[25] POKORNÝ V, ŠTEJFA V, HAVLÍN J, et al. Heat Capacities of l-Histidine, l-Phenylalanine, l-Proline, l-Tryptophan and l-Tyrosine[J/OL]. Molecules (Basel, Switzerland), 2021, 26(14): 4298.
[26] TAN K S, CHEONG K Y. Mechanical properties of sintered Ag–Cu die-attach nanopaste for application on SiC device[J/OL]. Materials & Design, 2014, 64: 166-176.
[27] YAN J, ZOU G, ZHANG Y, et al. Metal–Metal Bonding Process Using Cu+Ag Mixed Nanoparticles[J/OL]. Materials Transactions, 2013, 54(6): 879-883.
[28] V. R. MANIKAM, K. Y. CHEONG. Die Attach Materials for High Temperature Applications: A Review[J/OL]. IEEE Transactions on Components, Packaging and Manufacturing Technology, 2011, 1(4): 457-478.
[29] KIM M, LEE J H. Die sinter bonding in air using Cu@Ag particulate preform and rapid formation of near-full density bondline[J/OL]. Journal of Materials Research and Technology, 2021, 14: 1724-1738.
[30] CAZAYOUS M, LANGLOIS C, OIKAWA T, et al. Cu-Ag core-shell nanoparticles: A direct correlation between micro-Raman and electron microscopy[J/OL]. Physical Review B, 2006, 73(11): 113402.
[31] DAI X, XU W, ZHANG T, et al. Room temperature sintering of Cu-Ag core-shell nanoparticles conductive inks for printed electronics[J/OL]. Chemical Engineering Journal, 2019, 364: 310-319.
[32] 李雅丽, 刘娟, 党蕊. 银包覆铜微粉的制备与性能研究[J/OL]. 应用化工, 2011, 40(12): 2135-2137.
[33] 刘志杰, 赵斌, 张宗涛, 等. 超细核壳铜-银双金属粉的制备[J]. 无机化学学报, 1996(1): 30-34.
[34] 蒋红梅. 铜-银双金属粉的制备机理研究[J]. 沈阳农业大学学报, 2001(2): 141-143.
[35] 徐振宇, 秦会斌. 铜-银双金属粉末的制备及其包覆性[J/OL]. 杭州电子工业学院学报, 2002(6): 69-72.
[36] 常英, 刘彦军. 片状镀银铜粉的制备及性能表征[J]. 化工新型材料, 2005(4): 56-58.
[37] XU X, LUO X, ZHUANG H, et al. Electroless silver coating on fine copper powder and its effects on oxidation resistance[J/OL]. Materials Letters, 2003, 57(24): 3987-3991.
[38] 廖辉伟, 李翔, 彭汝芳, 等. 包覆型纳米铜-银双金属粉研究[J]. 无机化学学报, 2003(12): 1327-1330.
[39] 李哲男, 董星龙, 王威娜. 铜系导电涂料中纳米铜粉抗氧化问题的研究[J]. 四川大学学报(自然科学版), 2005(S1): 226-230.
[40] LI J, YU X, SHI T, et al. Depressing of CuCu bonding temperature by composting Cu nanoparticle paste with Ag nanoparticles[J/OL]. Journal of Alloys and Compounds, 2017, 709: 700-707.
[41] TAN K S, CHEONG K Y. Mechanical properties of sintered Ag–Cu die-attach nanopaste for application on SiC device[J/OL]. Materials & Design, 2014, 64: 166-176.
[42] YAN J, ZOU G, WU A ping, et al. Pressureless bonding process using Ag nanoparticle paste for flexible electronics packaging[J/OL]. Scripta Materialia, 2012, 66(8): 582-585.
[43] TIAN Y, JIANG Z, WANG C, et al. Sintering mechanism of the Cu–Ag core–shell nanoparticle paste at low temperature in ambient air[J/OL]. RSC Advances, 2016, 6(94): 91783-91790.
[44] LIU X, LIU W, WANG C, et al. Preparation and Sintering Properties of Ag27Cu2Sn Nanopaste as Die Attach Material[J/OL]. Journal of Electronic Materials, 2016, 45(10): 5436-5442.
[45] KOTTHAUS S, GUNTHER B H, HANG R, et al. Study of isotropically conductive bondings filled with aggregates of nano-sited Ag-particles[J/OL]. IEEE Transactions on Components, Packaging, and Manufacturing Technology: Part A, 1997, 20(1): 15-20.
[46] YANG W, CHEN J, ZHANG Y, et al. Silicon-Compatible Photodetectors: Trends to Monolithically Integrate Photosensors with Chip Technology[J/OL]. Advanced Functional Materials, 2019, 29(18): 1808182.
[47] LI S, LIU X, FAN J, et al. Research on Thermal-Mechanical Properties of GaN Power Module Based on QFN Package by Using Nano Copper/Silver Sinter Paste[C/OL]//2022 23rd International Conference on Electronic Packaging Technology (ICEPT). 2022: 1-7
[2024-03-19].
[48] 吴艳. 电子封装用核壳结构Cu@Sn@Ag焊片焊接过程的应力仿真分析[D/OL]. 北方工业大学, 2023
[2024-03-19].
[49] 杨龙龙. 多场耦合下倒装芯片封装焊点电迁移可靠性研究[D/OL]. 南通大学, 2017
[2024-03-19].
[50] YANG G, ZOU Q, WANG P, et al. Towards understanding the facile synthesis of well-covered Cu-Ag core-shell nanoparticles from a complexing model[J/OL]. Journal of Alloys and Compounds, 2021, 874: 159900.
[51] KING J T, ROSS M R, KUBARYCH K J. Water-Assisted Vibrational Relaxation of a Metal Carbonyl Complex Studied with Ultrafast 2D-IR[J/OL]. The Journal of Physical Chemistry B, 2012, 116(12): 3754-3759.
[52] JI H, ZHOU J, LIANG M, et al. Ultra-low temperature sintering of Cu@Ag core-shell nanoparticle paste by ultrasonic in air for high-temperature power device packaging[J/OL]. Ultrasonics Sonochemistry, 2018, 41: 375-381.
[53] HUANG H J, WU X, ZHOU M B, et al. A highly reliable die bonding approach for high power devices by low temperature pressureless sintering using a novel Cu nanoparticle paste[C/OL]//2020 IEEE 70th Electronic Components and Technology Conference (ECTC). 2020: 1697-1702
[2024-03-19].
[54] 刘徐迟. 低成本银包覆铜导电浆料的可控制备及其在太阳能电池中的应用[D/OL]. 上海交通大学, 2020
[2024-03-19].
[55] JIANG R, ZHONG C, PENG X, et al. Investigation on Reliability of Power Devices by Finite Element Analysis[C/OL]//2022 23rd International Conference on Electronic Packaging Technology (ICEPT). 2022: 1-6
[2024-03-19].
[56] ZHANG X, ZHANG Y, DING Y, et al. Influence of Thermal Field Distribution on the Sintering Performance of Ag Micron-flakes[C/OL]//2022 23rd International Conference on Electronic Packaging Technology (ICEPT). 2022: 1-6
[2024-03-19].
[57] BASARAN C, YAN C Y. A Thermodynamic Framework for Damage Mechanics of Solder Joints[J/OL]. Journal of Electronic Packaging, 1998, 120(4): 379-384.
[58] E.B. Choi, J.H. Lee, Dewetting behavior of Ag in Ag-coated Cu particle with thick Ag shell, Appl. Surf. Sci. 480 (2019) 839–845.