SUSS MicroTec, Advanced Mask Aligner Lithography - AMALITH

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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

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

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

HISTORIC LITHO TOOL PRICE [US$]

Mask Aligner

Front-End Litho Tool

ASML 1950i

Every 4 years the price doubled

[1970 – 2010]

LITHOGRAPHY FOR LED MANUFACTURING

Market Share LED Exposure ToolsSUSS

Mask Aligner

ASML Stepper

Beta Squareused Perkin Elmer

DNK Aligner

Nikon Used Stepper

Ultratech Stepper

Ushio full-field

EVGMask Aligner

ELS Aligner

China 102 23 3 128

80% 18% 2%

Europe 6 1 1 8

75% 13% 13%

Japan 22 22

Korea 14 9 25 1 2 51

27% 18% 49% 2% 4%

Malaysia 4 1 5

80% 20%

Singapore 20 20

Taiwan 23 75 23 14 9 144

16% 52% 16% 10% 6%

USA 11 11

Worldwide 182 20 2 107 48 14 1 6 9 389

Source: www.yole.fr

„Shadow Printing“ Lithography

Mask illumination using collimated UV light

Resolution proximity gap

MASK ALIGNER LITHOGRAPHY

Diffraction effects

Proximity artifacts

Sidelobes

SHADOW PRINTING LITHOGRAPHY

Parallel Light

(sidelobes)

Apodization

Parallel Light Diffuse Light

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

MO EXPOSURE OPTICS®

The new Illumination System for all SUSS Mask Aligners

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.

KEY COMPONENTS: MICROLENS OPTICAL INTEGRATORS

Microlens Optical Integrator

Flat-Top Illumination Light Source

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 in SUSS MA8 Gen3 Mask Aligner Quick Plug & Play installation and IFP illumination filter exchange

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)

MO EXPOSURE OPTICS® : QUICK INSTALLATION

Quick Installation in Mask Aligner Microlens Optical Integrators

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

SUSS MicroTec, Advanced Mask Aligner Lithography (AMALITH)

MO Exposure Optics

installed!

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

MO Exposure Optics

installed!

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

TELECENTRIC MASK ILLUMINATION

Uniform angular spectrum of mask

illumination light over full mask area

Better resist sidewalls

Improved CD uniformity

ILLUMINATION FILTER PLATES (IFP)

IFP HR

Pupil Fill Ratio (PFR) 130%

IFP " More Light"

CONTACT OR PROXIMITY LITHOGRAPHY?

Changeover from

HR-Optics to LGO-Optics

in less than

5 minutes!

IFP-HR

„High Resolution“

IFP-LGO

„Large Gap“

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

SUSS MO Exposure Optics

IFP Circle 20

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

SUSS MO Exposure Optics

IFP Circle 20

SHADOW PRINTING: PINHOLE CAMERA

Graph: Lorenz Stürzebecher, FhG-IOF

Pinhole Camera

Camera Obscura

SHADOW PRINTING: PINHOLE CAMERA!

Graph: Lorenz Stürzebecher, FhG-IOF

Pinhole Camera

Camera Obscura

Light source

(Object)

Image of the

light source

in resist

ADVANCED MASK ALIGNER LITHOGRAPHY (AMALITH)

Pushing the limits!

OPTICAL PROXIMITY CORRECTION (OPC)

CHANGING THE PINHOLE

Square10µm x 10µm, Proximity Gap 50µm, Photoresist AZ4110, 1.2um thick

Light Source

• Self-Calibrating

• Customized

Illumination

Photomask

• Binary

• OPC

Exposure

• Exposure Time

• Proximity Gap

Photoresist

• Negative/Positive

• Chemical Enhanced

Process Resist Exposure Mask Source

Wet Process

• Developer

• Prebake/Postbake

Light Source

• Customized

Illumination

Photomask

• Binary

• OPC

Exposure

• Exposure Time

• Proximity Gap

Photoresist

Wet Process

• Developer

Simulation

Holistic Litho

• Simulation of

Lithography

Process Chain

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

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

SOURCE MASK OPTIZATION

ITERATIVE OPTIMIZATION: LOOP FUNCTION

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)

Aspect Ratio is the ratio of

the width of a shape to its

height.

HIGH ASPECT RATIO

Photomask

Photoresist

MASK ALIGNER LITHOGRAPHY

15 µm

30 µm

100 µm

15 µm

30 µm

100 µm

10µm 10µm 4µm 10µm

STRUCTURES AND GEOTMETRIES FOR LITHOGRAPHY

bars with different

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

SINGLE LINE, 5UM WIDTH IN 5UM THICK AZ9260 RESIST

2D AERIAL IMAGE CROSS SECTION

100 µm

Broad Band illumination (g-, h- & i-line)

±3.5° 0.8° < < 1.6°

100 µm

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 200 Dose 400

Assit Feature: Frensel Zone Plate

Sub Resolution Assist

Features (SRAF) based

on analytic approach

Increase the sidewall

steepness

2D AERIAL IMAGE CROSS SECTION

Broad Band Illumination (g-, h- & i-line)

100 µm

10µm 4µm

±3.5°

10µm 4µm

0.8° < < 1.6° ±3.5° 0.8° < < 1.6°

FRESNEL ZONE PLATE (FZP): HIGH ASPECT RATIO VIAS

MOEO ±0.7° circular illumination

Gap: 30µm

Resist: AZ9260, 10 µm thick

Broad band illumination, dose 0.3 i-line illumination, dose 0.1

1.8µm

20 µm

40 µm

AERIAL IMAGE

Conventional mask

(3µm opening)

Resist after development

Developed

EXAMPLE: PACKAGING, TSV & 3DIC

Resulting Aerial Image

Illumination

Filter Plates (IFP)

Depth of focus

OPC Structure

(Fresnel-type)

11µm via at 800 µm proximity gap

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 µm Typical parameters for via printing

using OPC Fresnel Technology

Resulting Aerial

Image Depth of focus

11µm via at 800 µm gap

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)

ALTERNATING APERTURE PHASE SHIFT MASK (AAPSM)

30um gap

IFP HR

Air stack: 50um

50 µm

Binary Mask

PSM+OPC

Broad Band illumination

ALTERNATING APERTURE PHASE SHIFT MASK (AAPSM)

AZ1512, 2µm

Gap: 30µm

PSM Binary Mask PSM+OPC

Simulation

Experimental results

Simulation

Broad Band illumination

MO EXPOSURE OPTICS: SU-8

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

MO EXPOSURE OPTICS FOR SU-8

SUSS MA6 MOEO

Light Source

• Customized

Illumination

Photomask

• Binary

• OPC

Exposure

• Exposure Time

• Proximity Gap

Photoresist

Wet Process

• Developer

Simulation

Holistic Litho

• Simulation of

Lithography

Process Chain

www.suss.com

www.suss.ch