Using Ink-Jet Printing and Nanoimprinting for Microsystems

Transcription

1 Faculty of Electrical and Computer Engineering Institute of Semiconductor and Microsystems Technology Using Ink-Jet Printing and Nanoimprinting for Microsystems R. Kirchner*, A. Türke, W.-J. Fischer Institute of Semiconductor and Microsystems Technology Microsystems Chair NanoZEIT Nanoelektronik Zentrum TU Dresden Semicon Dresden 20/10/2010

2 Scope 1 Introduction 2 Ink-Jet Printing 3 Nanoimprinting 4 Hybrid Approaches Submicron patterning and Ink-Jet 5 Summary

3 1 - Microsystems and Nano? MNI ITRS Roadmap 2009 Edition, Executive Summary Section, p.20 slide 3

4 1 - System Integration Techniques Ink-Jet Printing ~ 30 µm resolution Broad material spectrum (inks and substrates) no topography Microcontact Printing (µcp) ~ ( ) nm resolution no topography Nanoimprinting sub-50 nm resolution Binary masks or direct patterning 3D patterning B. J. Larson, New Technologies for Fabricating Biological Microarrays, University of Wisconsin-Madison, 2005, Dissertation, p. 132 Y. Xia et al., Angew. Chem. Int. Ed. 37 (1998), pp. 550 S. Y. Chou et al., J. Vac. Sci. Technol. B, 15/6, 1997 slide 4

5 2 - Ink-Jet Printing Advantages contactless additive nearly independent from substrate material Disadvantages low throughput inks are expensive annealing processes after printing process Characteristics heatable x-y table 2 cameras: drop watcher fiducial camera printheads (single use) DIMATIX DMP-2800 slide 5

6 2 Ink Materials Ink-Jet Printing Conductive inks Metal nanoparticles Metal-organic Precursors PEDOT Polypyrrole Semiconductor inks Polythiophene Pentacene Insulator inks PMMA Polystyrene Poly(4-vinylphenol) Conductive path Elec. contacts Transistors OLED Insulator layers slide 6

7 2 Conductive Inks Metal-organic precursors Metal nanoparticles O O - Ag C 30 min Ag + organ. residues Dependency of nanoparticle size on melting temperature 100 Sample we eight (%) Temperature ( C) Szczech et al., Microscale Thermophysical Engineering, 2004, 8, 327 slide 7

8 2 Drop Watcher slide 8

9 2 Silver Neodecanoate Dependency of ink jet printing conditions on the electrical properties Shee et resistance [Ohm/sq] 0,07 0,06 0,05 0,04 0,03 0,02 0,01 20 µm Drop distance 15 µm Drop distance 10 µm Drop distance Number of layers Ink jet printing of antenna structurs for RFID-applications (890 MHz and 2,4 GHz) Range: 890 MHz - 80 cm 2,4 Ghz - 15 cm 2 cm Heat treatment after printing process slide 9

10 2 Silver-Hybrid-Particle Ink Combination of organic and inorganic properties Conducting films can achieved at room temperature in situ generation of silver nanoparticles 500 nm 500 nm slide 10

11 Nanoimprint Lithography (NIL) Basic principles Thermal (T-NIL) UV assisted (UV-NIL) T-NIL Hybrid techniques UV-NIL + Lithography T-NIL + Lithography UV-NIL slide 11

12 3 - NIL Strategies Binary patterning sub-50 nm resolution aspect ratio 2:1, 1:1 overlay / multi-layer designs critical CMOS, patterned media Direct patterning sub-300 nm resolution aspect ratio: 5:1 to 10:1 single layer layout / mix-n-match waveguides, microfluidics, microlenses, MOEMS D. J. Resnick et al., Proc. SPIE Vol (2007), pp T M. D. Stewart et al., Proc. SPIE Vol (2005), pp. 210 H. Schmitt et al.; Microelectron. Eng. 87 (2010), pp slide 12

13 3 - Microring Resonator (MRR) Characteristic Optical resonator Functional gap ~ 250 nm Specific binding of analytes 1 µm deep cavity Technology requirement High pattern fidelity Low-cost patterning (sub-300 nm resolution) Low surface roughness Broad material spectrum 250 nm wide ridge slide 13

14 3 - MRR Imprint Process Step-and-repeat UV-NIL Low viscous imprint material Imprint chips / no stitching Rigid quartz mold Organic antisticking coating (Perfluorinated silane) slide 14

15 3 - Imprinted MRR I 250 nm gap resolved Aspect ratios > 4:1 Thick residual layer (~ 700 nm) Optimization (Resist volume, imprint parameters, imprint mold) slide 15

16 3 - Hybrid UV-NIL Technique (CNP) Advantages Increased aspect ratio residual layer free No post-processing Less cure-shrinkage stress Simulation Near-field lithography Discontinous-Galerkin simulation Residual layer < λ Resist for sub-λ Resist features A. Hille et al., J. Computat. Theoret. Nanosc. 7 (2010), p slide 16

17 3 - DG-simulations on quartz SiO 2 (175 nm residual layer) Near-field regime Sub- λ Resist gap resolved in resist Resist (limited diffraction effects) µm SiO 2 on Si (175 nm r. layer) Gap exposed by reflected light (idealized situation)

18 3 - Imprinted MRR II on native SiO 2 on Si on SiO 2 wafer 70 nm residual layer locally confined residual layer no residual layer slide 18

19 3 A New Technique: NT-UV-NIL Characteristics Non collimated light Indirect polymer curing (reflection, diffraction, scattering) UV-NIL characteristics 250 nm Advantages Bonded imprint molds (cost efficient Si-Molds) NEW UV-NIL mold materials Alternative antisticking layers Opaque working stamps R. Kirchner et al., Patent DE slide 19

20 4 Outlook I µcp & InkJet printing Organic field effect transistor (ofet) µcp: InkJet: short-channel geometry organic semiconductor, gate isolator, electrodes A. Heinzig, Diploma thesis (2007), Technische Universtität Dresden, Dep. Elect. Eng. And Comput. Sience, Microsystems Chair W. Lei, Project work (2010), Technische Universtität Dresden, Dep. Elect. Eng. And Comput. Sience, Microsystems Chair slide 20

21 4 Outlook II Nanoimprinting & InkJet printing Organic field effect transistor (ofet) NIL: InkJet: short-channel geometry / electrodes organic substrates organic semiconductor, gate isolator 295 nm 2 µm 10 µm 2 µm 40 µm L. Teng, Diploma thesis (2010), Technische Universtität Dresden, Dep. Elect. Eng. And Comput. Sience, Microsystems Chair slide 21

22 5 - Summary Conductive hybrid inks were synthesized for inkjet printing. Nanoimprinting enables direct patterning of functional structures for microsystems. Further extensions and integration of 3D structures are possbile. CNP is well suited for residual layer free immprinting and thus for functional imprint materials. NT-UV-NIL enables cost-efficient Si molds, new UV-NIL mold materials and alternative antisticking approaches. InkJet and nanoimprinting enables an efficient integration of functional structures into microsystems (= micro-nano-integration)

23 Thanks to DFG (DFG 1401/1) Nano- and Biotechnologies for Packaging of Electronic Systems Colleagues and Students at TU Dresden/IHM Fraunhofer-IPMS SAW Components / Mühlbauer THANK YOU 200 nm

24 Functional Imprint Resist R. Kirchner et al., 6 th nanomed, 2009, p ISBN R. Kirchner et al., Engineering of Functional Interfaces, 2010 (Physica Status Solidi proceedings) slide 24

25 Silane Antisticking Layers Standard NIL surfaces very low surface free energy Chemical-mechanical degradation CNP mold surfaces Chemical heterogenous surface Inhomogenous antisticking layers Material dependant degradation rates < 100 UV-NIL imprints Alternative antisticking materials Resist modifications R. Kirchner et al., Proc. of the SPIE Vol. 7545, 2010, 75450U R. Kirchner et al., 23rd Int. Conf. Microproc. and Nanotechnology Conf. acc.for publ. slide 25

26 MRR Imprint Mold Characteristic Sparse patterned (10 % etched) Negative mold 1 µm etch depth (SiO 2 ) CD 200 nm 1 µm deep cavity 250 nm wide ridge slide 26

27 Mold Sticking Reasons Surface area Mechanical interlocking / Friction Interatomic forces (dispersive, polar) Antisticking materials Fluorinated silanes Fluorinated polymers Metal oxides Isoelectric point (IEP) determines interaction Basic polymer (electron donor) (e.g. PMMA) Acidic polymer (electron acceptor) (e.g. PVC) IEP Cr 2 O 3 ~ 7 E. McCafferty, J. Electrochem. Soc. 150 (7), 2003, pp. B342 slide 27