micro- and nano-technology · 2013-05-15 · micro- and nano-technology..... for optics 3.2...

INSTITUTE of APPLIED PHYSICSFriedrich-Schiller University Jena

U.D. U.D. ZeitnerZeitnerFraunhofer Institut fFraunhofer Institut füür Angewandte Optik und Feinmechanikr Angewandte Optik und Feinmechanik

JenaJena

Micro- and Nano-Technology...... for Optics

3.2 Lithography


“Printing on Stones”

Map of Munich

Stone Print


Contact Printing

resist

substrate

light

mask


Mask Aligner


Mercury Emission Spectrume - lineghi


Proximity Printing

resist

substrate

light

mask

proximity gap


Projection Lithography

resist

substrate

light

mask

projection optics


The inverse microscope

microscope lithography

microscope lens projection lens

imageobject

image object

light source

light source


Photolithography Examples


ASML-Stepper


Zeiss SMT, WO 2003/075049

… for DUV-Lithography

Stepper Objective …

…aspheric lenses


Double Patterning


Principle ofhalf tone masks

Principle ofgray tone masks

brightness in the wafer plane

0

1

2

-1

-2grating period or pitch > λ

0

1

2

-1

-2

0

1

2

-1

-2

0 0 0

grating period ore pitch < λ

small medium highfilling factor:

blocking of higher orders by a lens

- Sub wavelength masks- HEBS glass masks- LDW glass masks

higher orders do not exist

Physics of Half-Tone- and Gray-Tone-Masks


half tone mask

objective

gray tone image

pulse densitypulse width

type of masks

+1-1

Courtesy of K. Reimer, ISIT/FhG

Also possible:

- combinations

- Error diffusion

Half-Tone Lithography


Holography Examples


12

3 4

5

67special features:

• adjustable angle of incidence: 0deg- 55deg ( ±1deg ) • low divergence: 0.1deg• interference filter: 313nm, 365nm, 435nm

1234567

mercury lampcollimatorpolarizerinterference filtercold-light mirrormasksubstrate

Mask Aligner With Collimated Illumination

12

3 4

5

67

oblique incidence

normal incidence Suss MA6-NFH


h

ϕL

-1st0thϕ0ϕ-1

d b

Two beam interference Symmetricdiffraction angles

only 0th and -1st order→ wavelength

dd

23

2 << λ

Littrow - mounting→ angle of incidence

dL 2sin

λϕ =

Parameters:• Wavelength λ / Pitch d • Angle of incidence ϕ• Groove depth h

Duty cycle f = b / d

rigorous calculations→ duty cycle and

groove depth of themask grating

Equal intensities

Mask

ResistSubstrate

Principle of Pattern Transfer


Experimental Results

1 µm

1 µm

Mask

Copy

Phase mask Amplitude mask

1 µm


λ/2 < p < 3λ/2 λ/2 < p < λ

pmp

p p=pm/2

Incidence Angle

� also usable for gratings with different orientations (e.g. circular gratings)


Laser Lithography


Laser Lithography – Scanning Beam

scanwidth

AOD

U~ deflection angle

substrate motion

AOM

U~ profile

mirror

focusing lens


DWL 400-FF Laser Writer

HIMT


basis system: DWL 400, Heidelberg InstrumentsLaser: He-Cd, λ=442nmmax. writing field: 200mm x 200mmmin. spot size: ∼1µmautofocus system: opticalwriting mode: variable dose (max. 64 level)

spot positioning by stage movement andbeam deflectionlateral scan (width up to 200µm at max. resolution)

writing speed: 10 – 20 mm²/min on planar substrates(depending on structure)

writing on curved substrates:substrate table: cardanic mount, tilt in two orthogonal axesmin. radius of curvature: ∼10mmmax. surface tilt angle: <10°max. sag: 30mm

DWL 400-FF Laser Writer


variable dose exposure:

development:

resist

substrate

intensity modulatedexposure beam

t1 t2x

y

e-beam,laser beam

writing pathsubstratemovement

• dose dependent profile depth after development process• high flexibility for arbitrary surface profiles

Lithography with variable dose exposure

micro- and nano-technology · 2013-05-15 · micro- and nano-technology..... for optics 3.2...

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