Inkjet. A microtool for Nanotechnology

Transcription

1 Nanotechnology for engineers Winter semester A microtool for Nanotechnology Nanotechnology for Engineers : J. Brugger (LMIS-1) & P. Hoffmann (IOA) Why 1. Data-driven 2. Non-contact 3. Precise deposition 4. No material waste 5. High rate 6. Non-planar deposition 7. Variety of materials Generation of 60µm diameter drops 2 1

2 From sprays to drop-on-demand Spray generated aerosols (> 100 years ago) Microdrop generation: (a few decades) Predetermined position On-demand Precise size Some dates: Controlled inkjet, Stanford Linear accelerator, 1992 Thermal invention, HP, Characteristics of Microdrops Size Deposition One-by-one generation possibility (on-demand) Precision deposition ability Generation rate 4 2

3 Drop generation I Acoustically Disrupted Continuous Jet Pressurized fluid input port Size 2xD Orifice Use of guide electrodes Application: Commercial cell sorters Modulation Voltage Cylindrical piezoelectric element Fluid Orifice 5 Drop generation II Thermal Drop-on-demand Easy to integrate Lack of flexibility Application: Desk printers (HP, Canon) Heater element Orifice Gas bubble 6 3

4 Drop generation III Piezoelectric pressure pulse Tailored pulse Flexible Complex fabrication process Piezoelectric element Orifice 7 Drop generation IV Other techniques: Focused acoustic beam ejection Liquid Spark Electrohydrodynamic 8 4

5 Equipment I Source: 9 Equipment II Transducer Orifice Substrate motion Substrate 10 5

6 Equipment III Source: 11 in LMIS fluid supply sealing body electric supply piezo actuator heater temperature sensor sealing nozzle 12 6

7 Kinetics of Microdrops I Small diameter Stokes law Re = vd /ν Re Dynamic Pressure Force/Viscous Force Where v = Drop velocity relative to air d = Drop diameter 2 η ν = Kinematic viscosity of air (0.151cm /sec at standard temperature and pressure) = ρ η = Viscosity of air ( ρ = Density of air ( gr/cm ) -6 gr/cm.s at STP) 13 Kinetics of Microdrops II The resistance caused by the air F Stokes = 6πηrv Dynamic pressure forces (e.g. aircrafts) A = Frontal area C d = F Drag Drag coefficient 1 = ρc d Av

8 Corrections of the Stokes law Millikan resistance factor (slip) The atmosphere is not a perfect continuum 1/C M x F s C M = 1+ (2λ / d)( A + Qe A = Q = b = λ = 0.065µ m d = Drop diameter bd / 2λ Buoyancy Correction Internal Drop Flow, Nonspherical Drops, ) 15 Impact Dominated by surface energy effects E Surface = 4πσr 2 Impact of a microdrop with the surface of water 16 8

9 Multiphase Transport Phenomena Pre-impact Spreading Post-spreading oscillations Impact and solidification on a solid substrate Final shape 17 Applications: Electrical interconnects Jetting of solders (Sn, Pb, Ag, In, Bi) Formation of spheres of µm of diameter High-rate drop formation: 1000/sec High operation temperatures: 320 C 18 9

10 Applications: Electronic passives Jetting of Filled polymers Conductive polyimide inks Challenges Materials (Silver, gold, copper) Postprocessing temperatures Ink-jet printed resistors; carbon nanotubes in a UV curing epoxy matrix 19 Applications: Displays Light Emitting Polymer (LEP) displays Philishave LEP Display Printed LEP Substrate Source:

11 Other Applications I Package sealing Bumps of 25µm in diameter and 10µm high have been created 95µm diam. 34µm high spacer bumps Sensors and active elements Chemical sensor materials, Light-emitting and semiconducting polymers Challenge: uniform layers of 100nm Light-emitting polymer printed into 80x100µm wells in a color display 21 Other Applications II 3D assembly 1 or 2 axes movement possibility Non-flat surfaces Solder bumps printed into corners Microlenses printed onto 100µm diameter pedestals Surface creation, modification and activation Locally control of surface wetting or reactivity 500µm regions of polypropylene modified by ink-jet printing of acetone 22 11

12 Nanoengineering with ting on nanostructured substrates ting on SAM Nano-carrier 23 12