Presentation is loading. Please wait.

Presentation is loading. Please wait.

(and briefly, Electrodeposition)

Similar presentations

Presentation on theme: "(and briefly, Electrodeposition)"— Presentation transcript:

1 (and briefly, Electrodeposition)
Lithography (and briefly, Electrodeposition) bnl ibm UMass manchester July 10, 2008: Nano Education Institute at UMass Amherst

2 How do we control the shape and size of nanostructures?
Self Assembly (inspired by nature) Lithography (designed by humans)

3 Nanostructures nanofilm, macroscale (3D) object or nanolayer (2D)
height depth width nanoparticle, nanodot, quantum dot (0D) nanowire, nanorod, or nanocylinder (1D)

4 Computer Microprocessor "Heart of the computer" Does the "thinking"

5 Making Small Smaller An Example: Electronics-Microprocessors
microscale nanoscale macroscale

6 Nanofilms (making thin objects, controlling the thickness)

7 An example of a FILM A monolayer NANOFILM (single layer of molecules)
~1 nm thick Langmuir film This is an example of SELF-ASSEMBLY

8 Nanofilm by Electrodeposition
("electroplating") I V cathode anode CuSO4 dissolved in water Working Electrode (WE) Counter (CE) Cu(0) –> Cu2+ + 2e- "oxidation" If using an inert Pt electrode: 2 H2O –> O2 + 4H+ + 4e- "reduction" Cu2+ + 2e- –> Cu(0)

9 A nanofilm method, Thermal Evaporation
sample QCM Vaporization or sublimation of a heated material onto a substrate in a vacuum chamber film vapor Au, Cr, Al, Ag, Cu, SiO, others Pressure must be held low to prevent contamination! vacuum ~10-7 torr source There are many other thin film manufacturing techniques resistive, e-beam, rf or laser heat source vacuum pump

10 Nanofilms (making thin objects)

11 From DOE

12 A Few Nanostructures Made at UMass
100 nm dots 70 nm nanowires 200 nm rings 150 nm holes 18 nm pores 12 nm pores 14 nm dots 13 nm rings 25 nm honeycomb 14 nm nanowires

13 Lithography (controlling width and depth, by using stencils, masks, & templates)

14 Nanoscience Rocks! Nanoscience Rocks
Lithography Nanoscience Rocks! Nanoscience Rocks (Using a stencil or mask)

15 Lithography: Basic concepts
Some possible desired features narrow trench narrow line modified substrate Photolithography Electron-Beam Lithography X-ray Lithography Focused Ion-Beam Lithography Block Copolymer Lithography Nano Imprint Lithography Dip Pen Lithography Interference Lithography Contact Lithography Others

16 Photolithography

17 Photolithography for Deposition
process recipe apply spin bake spin coating substrate spin on resist resist expose mask (reticle) exposed unexposed "scission" develop narrow line deposit liftoff

18 Lithography Patterned Several IBM Times Copper Wiring On a Computer

19 Other Uses Patterned Oxide Ion implantation Etching narrow trench
substrate silicon silicon oxide Patterned Oxide Other Uses spin on resist resist Ion implantation dopant ions (e.g., B+, P+) Etching expose mask develop after etch lift off narrow trench lift off

20 Positive and Negative Resists
Positive Resist Negative Resist resist resist expose expose scission cross-linking develop develop deposit & liftoff exposed region results in presence of structure exposed region results in absence of structure (generally poorer resolution)

21 Several Types of Lithography
lens contact proximity projection high resolution extends mask life enables "stepping"

22 Resolution Limit of PL How low can you go? minimum linewidth
There are actually many contributing factors that limit the minimum linewidth: optical diffraction () resist sensitivity depth of focus purity of light source numerical aperture of lens minimum pitch

23 Resolution in Projection Lithography
k1 ~ (depends on materials, optics and conditions) is wavelength of light used NA ~ is the numerical aperture of the lens system Rayleigh diffraction criterion—> 2bmin = 0.61/NA is part of the underlying reason With careful engineering, R ~/2 can be achieved Contact Lithography z is resist thickness Down to 45 nm

24 Electron-Beam Lithography

25 Electron-Beam Lithography
Polymer film Silicon crystal Nanoscopic Mask ! Down to 10 nm

26 CORE CONCEPT FOR NANOFABRICATION Deposition Template Etching Mask
Nanoporous Membrane (physical or electrochemical) Remove polymer block within cylinders (expose and develop) Down to 3 nm

27 Solar Cells Benefit: Sun is an unlimited source of electronic energy.

28 Electric Solar Cells Sunlight - + + -
Made from single-crystal silicon wafers (conventionally) Sunlight wires - cross-sectional view “load” n-type silicon Voltage p-type silicon + + - Current The load can be a lamp, an electric motor, a CD player, a toaster, etc

29 Nanostructured Solar Cells
Sunlight - “load” Voltage + Current More interface area - More power!

30 Next.... ....Electrodeposition

Download ppt "(and briefly, Electrodeposition)"

Similar presentations

Ads by Google