与光滑Cu具有高粘合性的聚酰亚胺制备及其界面研究

物联网、人工智能、5G通信和自动驾驶等技术的进步促使芯片封装朝着高速、轻薄和低功耗的方向发展。扇出型晶圆级封装利用再布线层将芯片的输入/输出端口扇出，是消费电子产品的重要封装形式之一。聚酰亚胺以其优异的综合性能作为层间介质层被广泛应用于再布线层中。由于材料本身的差异，再布线层中聚酰亚胺与光滑铜(Cu)线路之间无法形成有效的粘合，为再布线层的可靠性带来了挑战。针对此问题，本论文采用设计合成新型聚酰亚胺的方式，制备了两种能够与光滑Cu产生较好粘附性的聚酰亚胺材料：

本文对聚酰亚胺主链结构进行设计，合成了一系列具有柔性醚键及苯并咪唑结构的聚酰亚胺。通过调控主链中醚键的含量，实现聚酰亚胺分子链在Cu表面的均匀铺展。醚键的引入有效提升了聚酰亚胺在Cu表面的粘附性，其平均剥离强度高达1.674 N/3mm；同时其力学性能也获得提升，断裂伸长率高达11.3%，拉伸强度为156 MPa。此外，该系列聚酰亚胺薄膜还显示了优异的热稳定性，T_g均大于340 ℃。

本文对聚酰亚胺的侧链结构进行设计，合成了一系列具有羧基侧基的聚酰亚胺。极性羧基降低了聚酰亚胺的表面能，并与Cu形成化学键合增加了其与Cu表面的平均剥离强度，其中平均剥离强度最高为0.841 N/3mm。通过采用三氮唑对上述聚酰亚胺进行共混改性，三氮唑结构中的氮孤电子对与Cu形成配位键，将其平均剥离强度提高至1.221 N/3mm。此外，其拉伸强度和断裂伸长率分别达到了135 MPa和20%。

本论文针对高速高频芯片封装的再布线层中光滑Cu与聚酰亚胺界面可靠性问题，提出了通过分子结构设计和共混改性两种方式合成新型聚酰亚胺的解决办法，所合成的聚酰亚胺具有优异的Cu粘附性，在高频通信的晶圆级封装中具有潜在应用价值。

Advances in the IOTs, AI, 5G communications and autonomous driving technologies have promoted the rapid development of advanced packaging technologies. Fan-out wafer-level packaging uses redistribution layers to fan out the Input/Output ports of the chip, and is one of the important packaging styles for consumer electronics. Polyimides are widely used in redistribution layers as dielectric materials due to its excellent comprehensive performance. The inability to form effective adhesion between polyimide and Cu lines poses a challenge to the reliability of the redistribution layer. Considering this problem, this thesis adopts the method of designing and synthesizing new types of polyimides which can produce better adhesion with smooth Cu:

In this thesis, the main chain structure of polyimide was designed, and polyimide with ether bonds and benzimidazole structure was synthesized. The content of ether bonds in the main chain was adjusted to realize the uniform spreading of molecular chains on the Cu surface. The ether bonds effectively improved the adhesion of polyimide on the Cu surface, and the average peel strength of reached 1.674 N/3mm. Simultaneously, the ether bonds optimized the mechanical properties of polyimide, and a maximum elongation at break of 11.3% and a maximum tensile strength of 156 MPa was achieved. And, all polyimide films showed excellent thermal stability, with T_g greater than 340 ℃.

In this thesis, the side chain structure of polyimide was designed, and polyimide with carboxyl group side group was synthesized. Polar carboxyl groups reduced the surface energy of polyimide, and formed chemical bonds with Cu to increase the average peel strength to 0.841 N/3mm. Triazole was used to modify polyimide by blending. The lone electron pair in the triazole structure formed coordination bonds with Cu, which promoted the adhesion of polyimide to Cu, reaching 1.221 N/3mm. Besides, the tensile strength and elongation at break reached 135 MPa and 20%, respectively.

In this thesis, two kinds of polyimides were synthesized by molecular structure design and blending modification, and the adhesion between the synthesized polyimide and Cu was greatly improved, which showed potential application in high-frequency communication wafer-level packaging.

[1] TSENG C-F, LIU C-S, WU C-H, et al. InFO (Wafer Level Integrated Fan-Out) Technology [Z]. 2016 IEEE 66th Electronic Components and Technology Conference (ECTC). 2016: 1-6.10.1109/ectc.2016.65
[2] FAN X. Wafer level packaging (WLP): fan-in, fan-out and three-dimensional integration; proceedings of the 2010 11th International Thermal, Mechanical & Multi-Physics Simulation, and Experiments in Microelectronics and Microsystems (EuroSimE), F, 2010 [C]. IEEE.
[3] LAU J H. Semiconductor advanced packaging [M]. Springer Nature, 2021.
[4] RAO V S, CHONG C T, HO D, et al. Development of high density fan out wafer level package (HD FOWLP) with multi-layer fine pitch RDL for mobile applications; proceedings of the 2016 IEEE 66th Electronic Components and Technology Conference (ECTC), F, 2016 [C]. IEEE.
[5] YU C, YEN L, HSIEH C, et al. High performance, high density rdl for advanced packaging; proceedings of the 2018 IEEE 68th Electronic Components and Technology Conference (ECTC), F, 2018 [C]. IEEE.
[6] LAU J H. Recent Advances and Trends in Advanced Packaging [J]. IEEE Transactions on Components, Packaging and Manufacturing Technology, 2022, 12(2): 228-52.
[7] 周晓阳. 先进封装技术综述 [J]. 集成电路应用, 2018, 35(6): 1-7.
[8] 曹立强, 侯峰泽, 王启东,等. 先进封装技术的发展与机遇 [J]. 前瞻科技, 2022, 1(3): 101-14.
[9] CHEN N-C, HSIEH T-H, JINN J, et al. A Novel System in Package with Fan-out WLP for high speed SERDES application; proceedings of the 2016 IEEE 66th Electronic Components and Technology Conference (ECTC), F, 2016 [C]. IEEE.
[10] LAU J H, LEE S-W R, CHANG C. Solder joint reliability of wafer level chip scale packages (WLCSP): A time-temperature-dependent creep analysis [J]. J Electron Packag, 2000, 122(4): 311-6.
[11] LAU J H. Recent Advances and Trends in Fan-Out Wafer/Panel-Level Packaging [J]. Journal of Electronic Packaging, 2019, 141(4).
[12] LAU J H. Fan-out wafer-level packaging [M]. Springer, 2018.
[13] LAU J H, LAU J H. FOWLP: Chip-First and Die Face-Down [J]. Fan-Out Wafer-Level Packaging, 2018: 127-143.
[14] HUA X, XU H, ZHANG L, et al. Development of chip-first and die-up fan-out wafer level packaging; proceedings of the 2017 IEEE 19th Electronics Packaging Technology Conference (EPTC), F, 2017 [C]. IEEE.
[15] LAU J H, LAU J H. FOWLP: Chip-Last or RDL-First [J]. Fan-Out Wafer-Level Packaging, 2018: 195-206.
[16] OOIDA M, TANIGUCHI F, IWASAKI T, et al. Advanced Packaging Technologies supporting new semiconductor application; proceedings of the 2016 IEEE CPMT Symposium Japan (ICSJ), F, 2016 [C]. IEEE.
[17] LAU J, TZENG P, LEE C, et al. Redistribution layers (RDLs) for 2.5 D/3D IC integration; proceedings of the International Symposium on Microelectronics, F, 2013 [C]. International Microelectronics Assembly and Packaging Society.
[18] LAU J, TZENG P, LEE C, et al. Redistribution layers (RDLs) for 2.5 D/3D IC integration [J]. Journal of Microelectronics and Electronic Packaging, 2014, 11(1): 16-24.
[19] BOGERT M T, RENSHAW R R. 4-Amino-0-Phalitic acid and some of its derivatives [J]. J Am Chem Soc, 1908, 30(7): 1135-1144.
[20] 丁孟贤. 聚酰亚胺:化学、结构与性能的关系及材料 [M]. 聚酰亚胺:化学、结构与性能的关系及材料, 2006.
[21] XU Z, CROFT Z L, GUO D, et al. Recent development of polyimides: Synthesis, processing, and application in gas separation [J]. Journal of Polymer Science, 2021, 59(11): 943-962.
[22] FINK J K. High performance polymers [M]. William Andrew, 2014.
[23] HOU S, XIE J, KUANG Y, et al. Fabrication, Mechanical and Dielectric Characterization of 3D Orthogonal Woven Basalt Reinforced Thermoplastic Polyimide Composites [J]. Journal of Textile Science and Technology, 2015, 1(01): 35.
[24] SNYDER R, THOMSON B, BARTGES B, et al. FTIR studies of polyimides: thermal curing [J]. Macromolecules, 1989, 22(11): 4166-4172.
[25] VINOGRADOVA S, VYGODSKII Y S, VOROB’EV V, et al. Investigation of the formation of polyamido-acids [J]. Polym Sci USSR, 1974, 16: 584.
[26] PRAVEDNIKOV A, KARDASH I Y, GLUKHOYEDOV N, et al. Some features of the synthesis of heat-resistant heterocyclic polymers [J]. Polymer Science USSR, 1973, 15(2): 399-410.
[27] MEYERS R. The polymerization of pyromellitic dianhydride with diphenylmethane diisocyanate [J]. Journal of Polymer Science Part A‐1: Polymer Chemistry, 1969, 7(10): 2757-2762.
[28] CARLETON P S, FARRISSEY JR W J, ROSE J S. The formation of polyimides from anhydrides and isocyanates [J]. Journal of Applied Polymer Science, 1972, 16(11): 2983-2989.
[29] JIANG Z, DU Z, XUE J, et al. Hierarchical structure and properties of rigid PVC foam crosslinked by the reaction between anhydride and diisocyanate [J]. Journal of Applied Polymer Science, 2018, 135(16): 46141.
[30] CHIEFARI J, DAO B, GROTH A M, et al. Water as solvent in polyimide synthesis II: Processable aromatic polyimides [J]. High Performance Polymers, 2006, 18(1): 31-44.
[31] BENDER T P, WANG Z Y. Synthesis of polyimides and segmented block copolyimides by transimidization [J]. Journal of Polymer Science Part A: Polymer Chemistry, 2000, 38(21): 3991-3996.
[32] EASTMOND G, PAPROTNY J. Scope in the synthesis and properties of poly (ether imide) s [J]. Reactive and Functional Polymers, 1996, 30(1-3): 27-41.
[33] KORSHAK V, RUSANOV A, KAZAKOVA G, et al. Reactions of aromatic nucleophilic nitro displacement in the synthesis of polyimides. Review [J]. Polymer Science USSR, 1988, 30(9): 1899-1921.
[34] TAKEKOSHI T. Synthesis of high performance aromatic polymers via nucleophilic nitro displacement reaction [J]. Polymer journal, 1987, 19(1): 191-202.
[35] BESSONOV M I, ZUBKOV V. Polyamic acids and polyimides [J]. Synthesis, Transformations and Structure, CRC Press, 1993.
[36] 王海平, 王标兵, 胡国胜, 等. 聚酰亚胺的研究进展及应用 [J]. 塑料制造, 2007, (11): 4.
[37] 长崎幸夫, 古性均, 宫本久惠, 等. 聚酰亚胺前体以及聚酰亚胺及其应用 [Z]. CN
[38] 刘金刚, 何民辉, 范琳, 等. 先进电子封装中的聚酰亚胺树脂 [J]. 半导体技术, 2003, 28(10): 5.
[39] 刘金刚, 杨海霞, 范琳, et al. 先进封装用聚合物层间介质材料研究进展; proceedings of the 2010年全国半导体器件技术研讨会, F, 2010 [C].
[40] MILLER A, REBIBIS K J, DUVAL F D, et al. The increasing role of polymers in advanced packaging-from stress buffer layers to wafer level underfills and Beyond [J]. Journal of Photopolymer Science and Technology, 2017, 30(1): 17-24.
[41] BUCHWALTER L. Adhesion of polyimides to metal and ceramic surfaces: an overview [J]. Journal of adhesion science and technology, 1990, 4(1): 697-721.
[42] AWAJA F, GILBERT M, KELLY G, et al. Adhesion of polymers [J]. Progress in polymer science, 2009, 34(9): 948-968.
[43] 庄永兵, 顾宜. 改善无胶型挠性覆铜板粘接性能的研究进展 [J]. 绝缘材料, 2012, (1): 5.
[44] LEE C-Y, MOON W-C, JUNG S-B. Surface finishes of rolled copper foil for flexible printed circuit board [J]. Materials Science and Engineering: A, 2008, 483: 723-726.
[45] NOH B-I, JUNG S-B. Effect of Ni-Cr layer on adhesion strength of flexible copper clad laminate [J]. J Electron Mater, 2009, 38: 46-53.
[46] WANG C, XIANG L, CHEN Y, et al. Study on brown oxidation process with imidazole group, mercapto group and heterocyclic compounds in printed circuit board industry [J]. Journal of Adhesion Science and Technology, 2015, 29(12): 1178-1189.
[47] KIM Y H, WALKER G F, KIM J, et al. Adhesion and interface studies between copper and polyimide [J]. Journal of Adhesion Science and Technology, 1987, 1(1): 331-339.
[48] METWALLI E, HAINES D, BECKER O, et al. Surface characterizations of mono-, di-, and tri-aminosilane treated glass substrates[J]. Journal of colloid and interface science, 2006, 298(2): 825-831.
[49] LIU T-J, CHEN C-H, WU P-Y, et al. Efficient and adhesiveless metallization of flexible polyimide by functional grafting of carboxylic acid groups [J]. Langmuir, 2019, 35(22): 7212-7221.
[50] INAGAKI N, TASAKA S, BABA T. Surface modification of polyimide film surface by silane coupling reactions for copper metallization [J]. Journal of Adhesion Science and Technology, 2001, 15(7): 749-762.
[51] ZHAO Z, HE Y, YANG H, et al. Aminosilanization nanoadhesive layer for nanoelectric circuits with porous ultralow dielectric film [J]. ACS Applied Materials & Interfaces, 2013, 5(13): 6097-6107.
[52] WAGNER-JAUREGG T, HACKLEY JR B E, LIES T, et al. Model Reactions of Phosphorus-containing Enzyme Inactivators. IV. 1a The Catalytic Activity of Certain Metal Salts and Chelates in the Hydrolysis of Diisopropyl Fluorophosphate1b [J]. J Am Chem Soc, 1955, 77(4): 922-929.
[53] CHAN-PARK M B, TAN S S. Thermal graft copolymerization of 4-vinyl pyridine on polyimide to improve adhesion to copper [J]. International Journal of Adhesion and Adhesives, 2002, 22(6): 471-475.
[54] XUE G, DAI Q P, JIANG S G. CHEMICAL-REACTIONS OF IMIDAZOLE WITH METALLIC SILVER STUDIED BY THE USE OF SERS AND XPS TECHNIQUES [J]. J Am Chem Soc, 1988, 110(8): 2393-2395.
[55] LIU T-J, SIL M C, CHEN C-M. Well-organized organosilane composites for adhesion enhancement of heterojunctions [J]. Composites Science and Technology, 2020, 193.
[56] CAMPOS M A, TRILLING A K, YANG M, et al. Self-assembled functional organic monolayers on oxide-free copper [J]. Langmuir, 2011, 27(13): 8126-8133.
[57] CAIPA CAMPOS M A, TRILLING A K, YANG M, et al. Self-assembled functional organic monolayers on oxide-free copper [J]. Langmuir, 2011, 27(13): 8126-8133.
[58] SU Y, DE ROOIJ M, GROUVE W, et al. The effect of titanium surface treatment on the interfacial strength of titanium – Thermoplastic composite joints [J]. International Journal of Adhesion and Adhesives, 2017, 72: 98-108.
[59] SATORU IWAMORI T M, SHIN FUKUDA, SHOUHEI NOZAKI, KAZUFUYU SUDOH AND NOBUHIRO FUKUDA, . Effect of an interfacial layer on adhesion strength deterioration between a copper thin film and polyimide substrates [J]. 1998, 51: 615-618.
[60] ZHONG A, LI J, ZHANG G, et al. Adhesion and Interface Studies of the Structure‐Controlled Polyimide with Smooth Copper for High‐Frequency Communication [J]. Advanced Materials Interfaces, 2022.
[61] 尤肖虎, 潘志文, 高西奇, 等. 5G移动通信发展趋势与若干关键技术 [J]. 中国科学:信息科学, 2014, 44(5): 551-563.
[62] 石东平, 唐祖义, 陈武. 趋肤效应的理论研究与解析计算 [J]. 重庆文理学院学报(自然科学版), 2009.
[63] 江涛. 趋肤效应的物理诠释 [J]. 广州师院学报：自然科学版, 1999, 20(9): 6.
[64] 郭昌宏, 李习周. 扇出型晶圆级封装技术及其在移动设备中的应用 [J]. 2022, (5).
[65] ANG A, KANG E, NEOH K, et al. Low-temperature graft copolymerization of 1-vinyl imidazole on polyimide films with simultaneous lamination to copper foils—effect of crosslinking agents [J]. Polymer, 2000, 41(2): 489-498.
[66] JANG J, JANG I, KIM H. Adhesion promotion of the polyimide–copper interface using silane‐modified polyvinylimidazoles [J]. Journal of applied polymer science, 1998, 68(8): 1343-1351.
[67] JEONGHOONSEO J, CHO K, PARK C E. Synthesis of polyimides containing triazole to improve their adhesion to copper substrate [J].
[68] 徐群杰，李春香，周国定，朱律均，林昌健. 3-氨基-1,2,4-三氮唑对铜的缓蚀性能和吸附行为 [J]. 物理化学学报, 2009, (25(1)): 86-90.
[69] 何曼君, 陈维孝, 董西侠. 高分子物理.修订版 [M]. 高分子物理.修订版, 2000.
[70] SEO J, KANG J, CHO K, et al. Synthesis of polyimides containing triazole to improve their adhesion to copper substrate [J]. Journal of Adhesion Science and Technology, 2002, 16(13): 1839-1851.
[71] LEE K-W. Adhesion of Dielectric Materials [J].
[72] LEE K W, WALKER G F, VIEHBECK A. Formation of polyimide- Cu complexes: improvement of direct Cu-on-PI and PI-on-Cu adhesion [J]. Journal of Adhesion Science and Technology, 1995, 9(8): 1125-1141.
[73] LIU J, LI J, WANG T, et al. Organosoluble thermoplastic polyimide with improved thermal stability and UV absorption for temporary bonding and debonding in ultra-thin chip package [J]. Polymer, 2022, 244.
[74] DANIELS T M, SREEARUNOTHIAL P, Phokharatkul D, et al. Flexible, graphene protected Ag nanoparticles–polyimide tape for use as a transparent Surface-Enhanced Raman Scattering (SERS) substrate and its application in pesticide detection[J]. Nano-Structures & Nano-Objects, 2023, 33: 100930.
[75] CHIU J M, WAHDINI I, SHEN Y N, et al. Highly Stable Copper Nanowire-Based Transparent Conducting Electrode Utilizing Polyimide as a Protective Layer[J]. ACS Applied Energy Materials, 2023.
[76] KHAIRULLIIINA E M, RATAUTAS K, Panov M S, et al. Laser-assisted surface activation for fabrication of flexible non-enzymatic Cu-based sensors[J]. Microchimica Acta, 2022, 189(7): 259.