液体密封的阴影掩膜版图案化技术研究

阴影掩膜是一种高通量的微图案制造技术，广泛应用于电子和能源器件的微纳加工。然而，掩膜版阴影区域存在由扩散引起的沉积缺陷，严重限制了图案的精度与分辨率，该问题在原子层沉积（atomic layer deposition, ALD）等具有高易渗透性的薄膜制备技术中尤为明显。
本论文提出了一种液体密封策略，通过引入粘性全氟聚醚油作为液体密封剂，在掩膜版和基底之间建立一层动态扩散屏障，解决了阴影区域的扩散沉积问题。利用全氟聚醚油抗吸附与无缺陷的特点，实现了掩膜版与基底间缝隙的完全移除，达到了分子水平的无缺陷密封。所选用的液体密封剂具有良好的热和化学稳定性，在毛细力的作用下可稳定存在于掩膜版与基底之间，且使用后易于去除。将该技术应用于ALD介电氧化物沉积，图案最小线宽达到100 μm，且对氧化物薄膜的生长速率与物化性质没有影响，初步实现了阴影掩膜技术在ALD中的应用探索。
该液体密封策略适用于不同的掩膜版、基底和薄膜沉积方法，可用于制备多类功能材料图案。例如，表面弯曲的阴影掩膜版、具有纳米孔道的阳极氧化铝掩膜版；硅片、塑料以及弹性体等基底；ALD、磁控溅射和热蒸发等沉积方法；氧化物和金属等功能材料沉积。本论文研究为阴影掩膜技术的发展提供了新的思路。

Shadow masking is a high-throughput manufacturing technique for creating large-scale patterns in electronic and energy systems. However, diffusion-caused deposition underneath the mask has been a long-standing challenge that limits its patterning accuracy, which is particularly severe in oxide dielectric patterning made by atomic layer deposition (ALD).
This paper proposes a liquid sealing strategy that utilizes viscous perfluoropolyether oil as a liquid sealing agent to establish a dynamic diffusion barrier between the mask and the substrate, addressing the issue of diffusion deposition in shadow regions. Leveraging the anti-adsorption and defect-free characteristics of perfluoropolyether oil, the strategy achieves complete removal of gaps between the mask and the substrate, ensuring a defect-free seal at the molecular level. The chosen liquid sealing agent exhibits excellent thermal and chemical stability, stably residing between the mask and the substrate under capillary forces and is easily removable after use. When applied to ALD dielectric oxides, this technology enhances pattern resolution compared to traditional shadow mask techniques, achieving a minimum linewidth of 100 micrometers without altering the growth rate or film properties of the ALD oxides.
The liquid sealing strategy is suitable for shadow masks with curved surfaces, anodized alumina masks with nanochannels, and substrates such as silicon wafers, plastics, and elastomers. Beyond ALD oxides, this approach significantly increases the pattern accuracy of sputtered oxides and thermally evaporated metals. The liquid sealing strategy provides new insights for shadow-mask-based patterning.

[1] LIU J, WANG J C, ZHANG Z T, et al. Fully stretchable active-matrix organic light-emitting electrochemical cell array[J]. Nature Communications, 2020, 11(1): 3362.
[2] KOKI T, TAKAFUMI U, NAOKO N, et al. Heterogeneous functional dielectric patterns for charge-carrier modulation in ultra flexible organic integrated circuits[J]. Advanced Materials, 2021, 33(45): e2104446.
[3] ERJUAN G, SHEN X, FELIX D, et al. Integrated complementary inverters and ring oscillators based on vertical-channel dual-base organic thin-film transistors[J]. Nature Electronics, 2021, 4(8): 588-594.
[4] XU M S, NAKAMURA M, SAKAI M, et al. High-performance bottom-contact organic thin-film transistors with controlled molecule-crystal/electrode interface[J]. Advanced Materials, 2007, 19(3): 371-375.
[5] TOMOYUKI Y, TAKASHI K, REN S, et al. A few-layer molecular film on polymer substrates to enhance the performance of organic devices[J]. Nature Nanotechnology, 2018, 13(2): 139-144.
[6] DU P P, LI J H, WANG L, et al. Efficient and large-area all vacuum-deposited perovskite light-emitting diodes via spatial confinement[J]. Nature Communications, 2021, 12(1): 4751.
[7] JUNHO B, YUSEOP S, HYUNGYU Y, et al. Quantum dot-integrated GaN light-emitting diodes with resolution beyond the retinal limit[J]. Nature Communications, 2022, 13(1): 1862.
[8] KEITH B, IOANNIS K. Micro light-emitting diodes[J]. Nature Electronics, 2022, 5(9): 564-573.
[9] CAI Y F, ZHU C Q, ZHONG W, et al. Monolithically integrated μLEDs/HEMTs microdisplay on a single chip by a direct epitaxial approach[J]. Advanced Materials Technologies, 2021, 6(6): 100214.
[10] REINKE M, KUZMINYKH Y, HOFFMANN P. Limitations of patterning thin films by shadow mask high vacuum chemical vapor deposition[J]. Thin Solid Films, 2014, 563: 56-61.
[11] JIAN S, ZHAO D L, ALEXANDER K, et al. Electron microscopy observation of TiO2 nanocrystal evolution in high-temperature atomic layer deposition[J]. Nano Letters, 2013, 13(11): 27-34.
[12] RACZ Z, SEABAUGH A. Characterization and control of unconfined lateral diffusion under stencil masks[J]. Journal of Vacuum Science Technology & B, 2007, 25(3): 857-861.
[13] ELINA F, MARIANNA K, MIKKO R, et al. Selective-area atomic layer deposition using poly (methyl methacrylate) films as mask layers[J]. Journal of Physical Chemistry C, 2008, 112(40): 15791-15795.
[14] SARAH A H, CORTINO S, CHRISTOS G T, et al. Simple masking method for selective atomic layer deposition of thin films[J]. Journal of Vacuum Science Technology & B, 2020, 38(2): 025001.
[15] PANKAJ B A, RISHI S, DHARMESH M, et al. Silicon shadow mask technology for aligning and in situ sorting of semiconducting SWNTs for sensitivity enhancement: a case study of NO2 gas sensor[J]. ACS Applied Materials & Interfaces, 2020, 12(36): 40901-40909.
[16] WANG X, LUO Y, LIAO J, et al. Selective-area growth of aligned organic semiconductor nanowires and their device integration[J]. Advanced Functional Materials, 2023, 34(7): 2308708.
[17] BAHLKE E M, MENDOZA A H, ASHALL T D, et al. Organic semiconductors: dry lithography of large-area, thin-film organic semiconductors using frozen CO2 resists[J]. Advanced Materials, 2012, 24(46): 6116.
[18] LEE S, SO C, SIM M K, et al. Ultrathin, flexible, and reusable silicon shadow masks manipulated via transfer printing[J]. Advanced Materials Technologies, 2023, 8(21): 2300721.
[19] YUDI T, TORU U, TAKASHI I, et al. Vacuum-ultraviolet promoted oxidative micro photoetching of graphene oxide[J]. ACS Applied Materials & Interfaces, 2016, 8(16): 10627-10635.
[20] LI Y, XU G, ZHU X, et al. A hierarchical dual-phase photoetching template route to assembling functional layers on Si photoanode with tunable nanostructures for efficient water splitting[J]. Applied Catalysis B: Environmental, 2019, 25(9): 118115.
[21] GADGIL V, TONG H, CESA Y, et al. Fabrication of nano structures in thin membranes with focused ion beam technology[J]. Surface Coatings Technology, 2009, 203(17): 2436-2441.
[22] PAN Z, GUO C, WANG X, et al. Wafer-scale micro-LEDs transferred onto an adhesive film for planar and flexible displays[J]. Advanced Materials Technologies, 2020, 5(12): 2000549.
[23] DASGUPTA P N, JOON H J, ORLANDO T, et al. Atomic layer deposition of lead sulfide quantum dots on nanowire surfaces[J]. Nano Letters, 2011, 11(3): 934-940.
[24] NIU W, LI X, KARUTURI K S, et al. Applications of atomic layer deposition in solar cells[J]. Nanotechnology, 2015, 26(6): 064001.
[25] LANGSTON C M, USUI T, PRINZ B F. Mechanical masking of films deposited by atomic layer deposition[J]. Journal of Vacuum Science & Technology A, 2012, 30(1): 01A153.
[26] SWEET W J, OLDHAM C J, PARSONS G N. Atomic layer deposition of metal oxide patterns on nonwoven fiber mats using localized physical compression[J]. ACS Applied Materials & Interfaces, 2014, 6(12): 9280-9289.
[27] BAPTISTE L, YU Y H, NICOLA M, et al. Flexible fluid-based encapsulation platform for water-sensitive materials[J]. Proceedings of the National Academy of Sciences of the United States of America, 2023, 120(34): e2308804120.
[28] WU J, PIKE R T, WONG C P, et al. Evaluation and characterization of reliable non-hermetic conformal coatings for microelectromechanical system (MEMS) device encapsulation[J]. IEEE Transactions on Advanced Packaging, 2000, 23: 721-728.
[29] 孙超, 孙帮雄, 马凤国. LED封装用高折射率液体硅橡胶的研究进展[J]. 有机硅材料, 2017, 31(1): 51-55.
[30] 毛步本. 新型液体密封[J]. 煤矿机电, 1986, 6(20): 52-53.
[31] GEORGE M S. Atomic layer deposition: an overview[J]. Chemical Reviews, 2010, 110(1): 111-131.
[32] AHVENNIEMI E, AKBASHEV A R, ALI S, et al. Review article: recommended reading list of early publications on atomic layer deposition-outcome of the "Virtual project on the history of ALD"[J]. Journal of Vacuum Science & Technology A, 2017, 35(1): 010801.
[33] LIN J, SHIN K, KIM H, et al. Enhancement of ZnO nucleation in ZnO epitaxy by atomic layer epitaxy[J]. Thin Soild Films, 2005, 475(1): 256-261.
[34] MISTRY K, ALLEN C, AUTH C, et al. A 45 nm logic technology with high-k metal gate transistors, strained silicon, 9 cu interconnect layers, 193 nm dry patterning and 100% Pb-free packaging[C]. Washington, DC: IEEE IEDM 2007 Proceedings, 2007: 247-250.
[35] GEORGE S M, OTT A W, KLAUS J W. Surface chemistry for atomic layer growth[J]. Journal of Physical Chemistry, 1996, 100(31): 13121-13131.
[36] LIU J L, JEFFREY W E, PETER C S. Synthesis and stabilization of supported metal catalysts by atomic layer deposition[J]. Accounts of Chemical Research, 2013, 46(8): 1806-1815.
[37] NICOLA P, MATO K. Atomic layer deposition of nanostructured materials[M]. Wiley-VCH Verlag GmbH Co KGaA, 2011.
[38] NIE S, EMORY S R. Probing single molecules and single nanoparticles by surface-enhanced raman scattering[J]. Science, 1997, 275: 1102-1106.
[39] YEE K S. Numerical solution of initial boundary value problems involving Maxwell’s equations in isotropic media[J]. IEEE Transactions on Antennas and Propagation, 1966, 14(3): 302-307.
[40] KRESSE G, FURTHMÜLLER J. Efficiency of ab initio total-energy calculations for metals and semiconductors using a plane-wave basis set[J]. Computational Materials Science, 1996, 6(1): 15-50.
[41] PERDEW J P, BURKE K, ERNZERHOF M. Generalized gradient approximation made simple[J]. Physical Review Letters, 1996, 78(7): 3865-3868.
[42] STEFAN G, STEPHAN E, LARS G. Effect of the damping function in dispersion corrected density functional theory[J]. Journal of Computational Chemistry, 2011, 32(7): 1456-1465.
[43] BRENNING H T, KUBATKIN S E, ERTS D, et al. A single electron transistor on an atomic force microscope probe[J]. Nano Letters, 2006, 6(5): 937-941.
[44] XANTHEAS S S. Ab initio studies of cyclic water clusters (H2O)n, n=1–6. III. Comparison of density functional with MP2 results[J]. The Journal of Chemical Physics, 1995, 102(11): 4505-4517.
[45] AGMON N. Estimation of the hydrogen-bond lengths to H3O+ and H5O2+ in liquid water[J]. Journal of Molecular Liquids, 1997, 73: 513-520.
[46] DAINTY J C. Laser speckle and related phenomena[J]. Applied Optics, 1984, 23(16): 2661.
[47] GOREN C, RABIN Y, ROSENBLUH M, et al. Elastic recovery of gels on mesoscopic length scales. A photon correlation spectroscopy study[J]. Macromolecules, 2000, 33(16): 5757-5759.
[48] PALOMBO F, FIORETTO D. Brillouin light scattering: applications in biomedical sciences[J]. Chemical Reviews, 2019, 119(13): 7833-7847.
[49] SEO S, WOO W, LEE Y, et al. Reaction mechanisms of non-hydrolytic atomic layer deposition of Al2O3 with a series of alcohol oxidants[J]. The Journal of Physical Chemistry C, 2021, 125(33): 18151-18160.
[50] PUURUNEN L R. Surface chemistry of atomic layer deposition: a case study for the trimethylaluminum/water process[J]. Journal of Applied Physics, 2005, 97(12): 121301.
[51] LIU T L, BENT S F. Area-selective atomic layer deposition on chemically similar materials: achieving selectivity on oxide/oxide patterns[J]. Chemistry of Materials, 2021, 33(2): 513-523.
[52] MYERS T, JAMES A T, BORRELLI R A, et al. Smoothing surface roughness using Al2O3 atomic layer deposition[J]. Applied Surface Science, 2021, 569(15): 150878.
[53] JINESH K B, SANDEN M C, FRED R, et al. Dielectric properties of thermal and plasma-assisted atomic layer deposited Al2O3 thin films[J]. Journal of The Electrochemical Society, 2011, 158(2): G21-G26.
[54] XIN W, KUMAR S G, MAHYAR A, et al. Atomic layer deposition of zirconium oxide thin films[J]. Journal of Materials Research, 2020, 35(7): 804-812.
[55] KIM C J, CHO S Y, MOON H S. Atomic layer deposition of HfO2 onto Si using Hf(NMe2)4[J]. Japanese Journal of Applied Physics, 2009, 48(6): 066515.
[56] DUFOND M E, MAIMOUNA W, BADIE C, et al. Quantifying the extent of ligand incorporation and the effect on properties of TiO2 thin films grown by atomic layer deposition using an alkoxide or an alkylamide[J]. Chemistry of Materials, 2020, 23(32): 1393-1407.