MO Exposure Optics (MOEO), is a novel mask aligner illumination system for all SUSS MicroTec Mask Aligners. Self-calibrating light source (no lamp alignment after lamp exchange), improved light uniformity, telecentric illumination and the possibility of freely shaping the angular spectrum are main advantages. Full control of the illumination allows to reduce diffraction effects, enhance resolution, improve CD uniformity and yield. It is now possible to fully simulate the lithography process by using LAB software from GenISys. Well known lithography techniques like customized illumination, optical proximity correction (OPC) and source-mask optimization (SMO) are now available for mask aligner lithography. Mask aligner lithography has entered a new era.

1. ADVANCED MASK ALIGNER LITHOGRAPHY (AMALITH)
Photolithography Enhancement for SUSS Mask Aligners
SÜSS MicroTec AG, www.suss.com
SUSS MicroOptics SA, www.suss.ch, info@suss.ch

2. 1969: MJB3 1985: MA150 2013: LithoPack Gen2
Mask Aligners are the loyal work horse in research and industry
since more than 50 years!
SUSS MASK ALIGNERS 1963 - 2013
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)2

3. LITHOGRAPHY IN 1980
Min. Feature Size
[Half-Pitch]
Year Micron
1957 120
1963 30
1971 10
1974 6
1976 3
1982 1.5
1985 1.3
1989 1
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)3

4. HISTORIC LITHO TOOL PRICE [US$]
Mask Aligner
Front-End Litho Tool
EUVL
ASML 1950i
Every 4 years the price doubled
[1970 – 2010]
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)4

5. LITHOGRAPHY FOR LED MANUFACTURING
Market Share LED Exposure Tools
SUSS
Mask Aligner
ASML
Stepper
Beta Square
used Perkin Elmer
DNK
Aligner
Nikon
Used Stepper
Ultratech
Stepper
Ushio
full-field
EVG
Mask Aligner
ELS
Aligner
China 102 23 3 128
80% 18% 2%
Europe 6 1 1 8
75% 13% 13%
Japan 22 22
100%
Korea 14 9 25 1 2 51
27% 18% 49% 2% 4%
Malaysia 4 1 5
80% 20%
Singapore 20 20
100%
Taiwan 23 75 23 14 9 144
16% 52% 16% 10% 6%
USA 11 11
100%
Worldwide 182 20 2 107 48 14 1 6 9 389
Source: www.yole.fr
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)5

6. „Shadow Printing“ Lithography
 Mask illumination using collimated UV light
 Resolution  proximity gap
MASK ALIGNER LITHOGRAPHY
Wafer
Mask
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)6

7.  Diffraction effects
 Proximity artifacts
 Sidelobes
SHADOW PRINTING LITHOGRAPHY
Parallel Light
(sidelobes)
Apodization
Parallel Light Diffuse Light
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)7

8.  Customized Illumination
 Reduce diffraction effects (apodization)
 Optical Proximity Correction (OPC)
 Improve critical resist structures
 Source Mask Optimization (SMO)
 Customized Illumination and OPC
 Alternating Aperture Phase Shift Mask (AAPSM)
 ...
PHOTOLITHOGRAPHY ENHANCEMENT
IN FRONT-END-OF-LINE WAFER STEPPERS
www.asml.com
www.zeiss.com
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)8

9. MO EXPOSURE OPTICS®
The new Illumination System for all SUSS Mask Aligners

10.  Lamp readjustment required
 Uniformity change over lamp lifetime
 Daily uniformity test required
 Variation of illumination light over mask
(angular spectrum)
CONVENTIONAL MASK ALIGNER ILLUMINATION
Forgot to control light
uniformity this morning.
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)10

11. KEY COMPONENTS: MICROLENS OPTICAL INTEGRATORS
Microlens Optical Integrator
Flat-Top IlluminationLight Source
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)11

12.  2x Microlens Integrators in the Mask Aligner
illumination system
 Light homogenization in both Fourier planes
 Self calibrating light source
 Illumination filter plate (IFP)
MO EXPOSURE OPTICS®
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)12
MO Exposure Optics in SUSS MA8 Gen3 Mask Aligner
Quick Plug & Play installation and IFP illumination filter exchange

13. MO EXPOSURE OPTICS®
SELF CALIBRATING MASK ALIGNER ILLUMINATION
Microlens Optical Integrators
 Lamp readjustment required
 Uniformity change over lamp lifetime
 Daily uniformity test required
 Variation of illumination light over mask
(angular spectrum)
NO
NO
NO
NO
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)13

14. MO EXPOSURE OPTICS® : QUICK INSTALLATION
Quick Installation in Mask AlignerMicrolens Optical Integrators
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)14

15.  Conventional Mask Aligner Illumination Optics (HR or LGO)
 Daily light measurement (9 or 12 points)  5 min x 365 day ~ 30 hours per year
 12x lamp exchange per year  30 min x 10 ~ 6 hours per year
 36 hours less productive time & labor costs per year
 MO Exposure Optics
 Self-calibrating light source
 No periodic uniformity and no lamp adjustment required
 No lamp adjustment, no issues with light uniformity
SELF CALIBRATING LIGHT SOURCE
Forgot to control light
uniformity this morning.
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)
MO Exposure Optics
installed!
15

16.  MO Exposure Optics®
 No uniformity measurements
 No lamp alignment
 Improved uniformity
 Telecentric illumination
 CD uniformity improvement = Yield!
 Process stability assurance = Yield!
 Convenience!
SELF CALIBRATING LIGHT SOURCE – SAFES TIME & MONEY
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)16
Forgot to control light
uniformity this morning.
MO Exposure Optics
installed!

17.  Excellent light uniformity
 No lamp misalignment
 No uniformity change due to degradation of
lamp electrode during lifetime cycle
BETTER UNIFORMITY – INDEPENDENT OF LAMP POSITION
Deviation from mean value in [%] for Ø200mm in
MA200 Compact
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)17

18. TELECENTRIC MASK ILLUMINATION
 Uniform angular spectrum of mask
illumination light over full mask area
 Better resist sidewalls
 Improved CD uniformity
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)18

19. ILLUMINATION FILTER PLATES (IFP)
IFP HR
Pupil Fill Ratio (PFR) 130%
IFP " More Light"
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)19

20. CONTACT OR PROXIMITY LITHOGRAPHY?
Changeover from
HR-Optics to LGO-Optics
in less than
5 minutes!
IFP-HR
„High Resolution“
IFP-LGO
„Large Gap“
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)20

21. COMPARISION: RESOLUTION FOR 100µM PROXIMITY GAP
Comparision of HR, LGO and MO Exposure Optics in MA6
Coating AZ 4110, Thickness = 1.2µm
Exposure MA6 (1KW lamp house), Proximity Gap 100µm
Developing Manual Developed. AZ400K (1:4 DI), 60sec
Lines 7µm
Lines 6µm
Lines 7µm
Lines 6µm
Lines 7µm
Lines 6µm
SUSS High-Resolution
Optics (HR)
SUSS Large Gap Optics
(LGO)
SUSS MO Exposure Optics
IFP Circle 20
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)21

22. COMPARISION: RESOLUTION FOR 300µM PROXIMITY GAP
Lines 20µm
Lines 10µm
Lines 20µm
Lines 10µm
Lines 20µm
Lines 10µm
Comparision of HR, LGO and MO Exposure Optics in MA6
Coating AZ 4110, Thickness = 1.2µm
Exposure MA6 (1KW lamp house), Proximity Gap 100µm
Developing Manual Developed. AZ400K (1:4 DI), 60sec
SUSS High-Resolution
Optics (HR)
SUSS Large Gap Optics
(LGO)
SUSS MO Exposure Optics
IFP Circle 20
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)22

23. SHADOW PRINTING: PINHOLE CAMERA
Graph: Lorenz Stürzebecher, FhG-IOF
Pinhole Camera
Camera Obscura
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)23

24. SHADOW PRINTING: PINHOLE CAMERA!
Graph: Lorenz Stürzebecher, FhG-IOF
Pinhole Camera
Camera Obscura
Light source
(Object)
Image of the
light source
in resist
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)24

25. ADVANCED MASK ALIGNER LITHOGRAPHY (AMALITH)
Pushing the limits!

26. OPTICAL PROXIMITY CORRECTION (OPC)
CHANGING THE PINHOLE
Square10µm x 10µm, Proximity Gap 50µm, Photoresist AZ4110, 1.2um thick
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)26

27. Light Source
• Self-Calibrating
• Customized
Illumination
Photomask
• Binary
• OPC
Exposure
• Exposure Time
• Proximity Gap
Photoresist
• Negative/Positive
• Chemical Enhanced
ProcessResistExposureMaskSource
Wet Process
• Developer
• Prebake/Postbake
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)27

28. Light Source
• Self-Calibrating
• Customized
Illumination
Photomask
• Binary
• OPC
Exposure
• Exposure Time
• Proximity Gap
Photoresist
• Negative/Positive
• Chemical Enhanced
ProcessResistExposureMaskSource
Wet Process
• Developer
• Prebake/Postbake
Simulation
Holistic Litho
• Simulation of
Lithography
Process Chain
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)28

29. PROCEDURE
 Iterative simulations of different OPC mask layers
 Export of the aerial image for the different
simulated settings
 Matlab data elaboration
 LayoutLAB resist (calibrated) simulation for the
resulting best profiles
LITHOGRAPHY SIMULATION: OPC DESIGN
Mask Layouts
LayoutLAB FLOW
Results
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)29

30.  Optimization of the mask pattern (Optical Proximity Correction, OPC)
LITHOGRAPHY SIMULATION: OPC DESIGN
Mask Layout Mask Layout
with OPC
features
Resist Profile Resist Profile
 LayoutLAB™ software from GenISys
 Fraunhofer IISB
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)30

31. SOURCE MASK OPTIZATION
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)31

32. ITERATIVE OPTIMIZATION: LOOP FUNCTION
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)32

33.  Simulation enables significant process improvements
 Customer purchased five MA200 Compact Mask Aligners
equipped with MO Exposure Optics®
INDUSTRY EXAMPLE:
REDUCTION OF PROXIMITY ARTIFACTS BY SMO
Proximity artifacts in redistribution lanes:
Deformations in lane edges.
Simulation LayoutLAB software
Corrected: 30µm Exp Gap, SB 90°C, 300sec, 650mJ
in MA200 Compact with MO Exposure Optics
Fillet reduces erosion
Source Mask Optimization (SMO)
Proximity artifact: Deformation
(protrusion) due to diffraction effects
(simulation in LayoutLAB)
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)33

34. Aspect Ratio is the ratio of
the width of a shape to its
height.
HIGH ASPECT RATIO
Photomask
Wafer
Photoresist
Gap
Height
Width
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)34

35. MASK ALIGNER LITHOGRAPHY
AirGap
0 µm
15 µm
30 µm
100 µm
0 µm
15 µm
30 µm
100 µm
10µm 10µm4µm10µm
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)35

36. STRUCTURES AND GEOTMETRIES FOR LITHOGRAPHY
bars with different
width
rectangles with
different shape
crossed bars in
near contact
different corner
structures
three bars
neighboring
contact holes
seven bars
contact hole near
to a bar
single bar
contact hole
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)36

37. SINGLE LINE, 5UM WIDTH IN 5UM THICK AZ9260 RESIST
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)37

38. 2D AERIAL IMAGE CROSS SECTION
100 µm
0 µm
GAP
Broad Band illumination (g-, h- & i-line)
±3.5° 0.8° <  < 1.6°
100 µm
0 µm
GAPSUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)38

39. SIMULATION – EXPERIMENT: KNIFE EDGE AT 100UM GAP
±0.7° circular illumination
Broad band illumination
Gap: 100µm
Resist: AZ9260, 10 µm thick
Light distribution in the resist
Resist after development
Developed
Not Developed
83.3°
71.3°
Dose 200Dose 400
Assit Feature: Frensel Zone Plate
 Sub Resolution Assist
Features (SRAF) based
on analytic approach
 Increase the sidewall
steepness
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)39

40. 2D AERIAL IMAGE CROSS SECTION
Broad Band Illumination
(g-, h- & i-line)
100 µm
0 µm
GAP
10µm 4µm
±3.5°
10µm 4µm
0.8° <  < 1.6°±3.5° 0.8° <  < 1.6°
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)40

41. FRESNEL ZONE PLATE (FZP): HIGH ASPECT RATIO VIAS
MOEO ±0.7° circular illumination
Gap: 30µm
Resist: AZ9260, 10 µm thick
3µm
Broad band illumination, dose 0.3 i-line illumination, dose 0.1
1.8µm
20 µm
40 µm
GAP
Light
17µm
AERIAL IMAGE
Conventional mask
(3µm opening)
TSV
Mask
Resist after development
Developed
Not
Developed
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)41

42. EXAMPLE: PACKAGING, TSV & 3DIC
Resulting Aerial Image
Illumination
Filter Plates (IFP)
Depth of focus
(DOF)
DOF
OPC Structure
(Fresnel-type)
11µm via at 800 µm proximity gap
TopviewSideviewSUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)42

43. EXAMPLE: PACKAGING, TSV & 3D IC
 Benefits
 Very large proximity gap
 Via shaping possible
 Extended Depth of Focus (DOF)
 Very short exposure time (focussing)
Gap Ø Via DOF
100 µm 2 µm 5 µm
200 µm 3 µm 15 µm
300 µm 5 µm 30 µm
400 µm 7 µm 60 µm
500 µm 10 µm 100 µm
700 µm 14 µm 200 µmTypical parameters for via printing
using OPC Fresnel Technology
Resulting Aerial
Image
Depth of focus
(DOF)
DOF
11µm via at 800 µm gap
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)43

44. PHOTOMASKS: PHASE SHIFT MASKS (PSM)
Source: PKL, Mask Technology & http://www.photomask.com/products/phase-shift-masks
Binary Chrome Mask Alternating Aperture Phase-Shift Mask (AAPSM)
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)44

45. ALTERNATING APERTURE PHASE SHIFT MASK (AAPSM)
30um gap
IFP HR
Air stack: 50um
0 µm
50 µm
GAP
0 µm
50 µm
GAP
0 µm
50 µm
GAP
PSM
Binary Mask
PSM+OPC
Broad Band illumination
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)45

46. ALTERNATING APERTURE PHASE SHIFT MASK (AAPSM)
AZ1512, 2µm
Gap: 30µm
PSMBinary Mask PSM+OPC
Simulation
Experimental results
Simulation
Experimental results
Simulation
Experimental results
Broad Band illumination
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)46

47. MO EXPOSURE OPTICS: SU-8
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)47

48. SU-8: IMPROVEMENT OF FOOTING & SIDEWALLS
 300µm thick SU8
Improvement of footing and sidewalls
with thick SU-8 using MO Exposure
Optics on SUSS MA56
SU8: 300µm thick, soft contact,
resolution 25µm
Courtesy: micro resist technology Berlin
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)48

49. MO EXPOSURE OPTICS FOR SU-8
SUSS MA6 MOEO
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)49

50. Light Source
• Self-Calibrating
• Customized
Illumination
Photomask
• Binary
• OPC
Exposure
• Exposure Time
• Proximity Gap
Photoresist
• Negative/Positive
• Chemical Enhanced
ProcessResistExposureMaskSource
Wet Process
• Developer
• Prebake/Postbake
Simulation
Holistic Litho
• Simulation of
Lithography
Process Chain
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)50

51. www.suss.com
www.suss.ch
SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)51