MO Exposure Optics: IFP - Guide - EPFL · SMO IFP-Guide;130711uvo.Doc Uwe Vogler 20.08.2013 2/14 2. ... best choice for working processes that were running with an A - O ptics before

SMO IFP-Guide;130711uvo.Doc Uwe Vogler

20.08.2013 1/14

MO Exposure Optics: IFP - Guide

General Remarks The Illumination Filter Plates (IFPs) are responsible for the creation of defined illumination

angles at the mask plane. The shape of the aperture is transformed into an angular

distribution of the light at the mask plane.

Example D-IFP:

Inserted into the MO

Exposure Optics the light

on the mask plane comes

from seven directions

The D-IFP is a metal

aperture with 7 holes

Every point on the mask plane is hit

by an identical angular light

distribution and intensity.

The angular distribution affects the resist image. Therefore it

can be optimized for every process. Process parameters as

resist-type, resist thickness, structure shapes and structure

sizes and proximity gap have a major impact on the resist-

image formation and have to be taken into account. Due to

this it is just possible to give some advices for the choice of

the right IFP for a process.

General rules for the right choice of IFPs 1. The IFP should be chosen for the most important process parameter: Different

shapes can improve different aspects of your lithography result. If there are

different structures on the mask but just a certain structure is critical for the

function of your device, you should choose an IFP to improve this certain structure.

If different shapes of structures on the mask are important for the function of the

device and critical to transfer into the resist, a more universal solution as the HR-IFPs

or a circle fitting to your gap should be chosen.


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2. Bigger openings can decrease diffraction effects: If diffraction effects have a bad

influence on the resist images (e.g. side lobes) such effects may be minimized by

using an IFP with a big opening.

3. Small openings can improve resist images for big gaps and resist steepness: To

receive proper lithography results using bigger proximity gaps (>100 µm) you need

to have small illumination angles, thus small openings of the IFPs. In the most cases

the shape of structures and the sidewall steepness can be increased with decreasing

opening sizes.


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IFP Design Description Page

HR – A - IFP 4

LGO - IFP 5

Medium Circle - IFP 6

Big Circle - IFP 7

D – IFP 8

Quadrupole – IFP 9

Quadrupole-45°-IFP 10

Small Ring – IFP 11

Big Ring – IFP 12


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Description:

HR – A - IFP

Recommended gap range: Recommended application:

Contact – 50 µm Replacement of classic “HR-A-Optics”

Remark:

The IFP creates illumination angles equal to the SUSS High Resolution Optics (HR-Optics) in

the so called A-Configuration (12 Lenses in triangular alignment). Therefore this IFP is the

best choice for working processes that were running with an A - Optics before an MO

Exposure Optics upgrade. In general the HR - IFPs, as the classic HR-A - Optics, is a good

choice for relatively small gaps and various structure shapes and sizes on one mask.

Example:

Simulation 2 µm AZ1518

30 µm proximity gap

3 µm lines and spaces

Mask pattern LGO-IFP HR-A-IFP HR-A-Optics


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Description:

LGO - IFP


> 80 µm Big Gaps / Replacement of LGO-Optics /

Steeper sidewalls Remark:

The LGO - IFP is designed to improve lithography results for big gaps. Compared to IFPs with

bigger openings it can allow to print structures down to the physical resolution limit for

larger gaps and increase wall steepness for standard DNQ positive resists. At smaller gaps

diffraction effects can appear more strongly using this IFP compared with IFPs with a bigger

opening.

Example:



7 µm squares (2D-periodic)

Mask pattern HR – A - IFP LGO - IFP


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Description:

Medium Circle - IFP


50 µm -150 µm Compromise for throughput at medium to

big gaps Remark:

The LGO IFP will in the most cases provide the best results for big gaps. The bigger opening

of the Medium Circle – IFP compared to the LGO - IFP causes a higher intensity and

therefore shorter exposure times with slightly less effect on the sidewalls than the LGO - IFP.

Example:



8 µm lines and spaces (2D-periodic)

Mask Pattern HR – A - IFP Medium Circle - IFP


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Description:

Big Circle - IFP


Contact – 50 µm Maximum throughput for uncritical layers

Remark:

The big aperture leads to the highest intensity of all IFPs and therefore the highest

throughput. In the recommended gap range the IFP decreases diffraction effects as side

lobes. Caused by the bigger illumination angles it can cause worse results than other IFPs

(e.g. sidewall steepness, image quality), especially for thick resists and big proximity gaps.

Example:



5.5 µm lines and spaces (2D-periodic)

Mask Pattern LGO- IFP Big Circle IFP


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Description:

D – IFP


Contact – 50 µm Replacement of classic “D-Optics”

Remark:

The IFP creates illumination angles equal to the SUSS Optics in the so called D - Configuration

(7 Lenses in hexagonal alignment). Therefor this IFP is the best choice for well-established

lithography steps that were running with a D - Optics before a MO Exposure Optics upgrade.

In general the HR-IFP, as the classic HR – A - Optics, is a good choice for relatively small gaps

and various structures shapes and sizes on one mask.

Example:



3 µm lines and spaces

Mask pattern LGO-IFP HR-D-Optics HR-D-IFP


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Description:

Quadrupole – IFP


50 µm - 100 µm Squared structures and corners

Remark:

The Quadrupole - IFP is designed for structures with a quadratic shape or in a quadratic

arrangement. Depending on the gap and on the specific structures it can work for

orthogonal structures parallel to the mask grid or structures with 45° rotation.

Example:



7 µm lines and spaces (horizontal periodic)

Mask Pattern HR-A-IFP Quadrupole-0°-IFP


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Description:

Quadrupole-45°-IFP


50 µm - 100 µm Squared structures and corners

Remark:

The Quadrupole - IFP is designed for structures with a quadratic shape or in a quadratic

arrangement. Depending on the gap and on the specific structures it can work for

orthogonal structures parallel to the mask grid or structures with 45° rotation.

Example:



4,5 µm Squares (2D-periodic)

Mask Pattern HR-A-IFP Quadrupole-45°-IFP


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Description:

Small Ring – IFP

Recommanded gap range: Recommended application:

50 µm - 150 µm Rotation-symmetric structures

Remark:

The ring formed IFPs are designed to reduce diffraction effects and they can work best

amongst others for rotation symmetric structures for bigger gaps.

Example:



8 µm Squares (2D-periodic)

Mask HR-A-IFP Small Ring IFP


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Description:

Big Ring – IFP


20 µm - 50 µm Rotation-symmetric structures

Remark:

The ring formed IFPs are designed to reduce diffraction effects and they can work best

amongst others for rotation symmetric structures. The bigger ring formed IFP mostly works

better for smaller proximity gaps.

Example:



3 µm Squares (horizontal periodic)

Mask Pattern HR-A-IFP Big Ring - IFP


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Current IFP-Sets (after July 2013)

IFP

Design Description MJB4

MA6

MA150

MA56

MA8Gen3 MA200

MA200Co MA300

D – IFP -- 100004089 -- -- --

HR – A - IFP 100005921 100004090 100006249 100018761 100018761

LGO - IFP 100005922 100004092 100006251 100018762 --

Big Circle - IFP 100006454 100004094 100006572 100006793 100006793


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IFP-Sets (before July 2013)

IFP

Design Description MJB4

MA6

MA150

MA56

MA8Gen3 MA200

MA200Co MA300

D – IFP 100006456 100004089 100006557 100006794 100006794

HR – A - IFP 100005921 100004090 100006249 100018761 100018761

LGO - IFP 100005922 100004092 100006251 100018762 tbd

Medium Circle - IFP 100006453 100004093 100006558 100006792 100006792

Big Circle - IFP 100006454 100004094 100006572 100006793 100006793

Quadrupole – IFP 100006458 100004095 100006571 100006795 100006795

Quadrupole-45°-IFP 100006459 100004096 100006570 100006796 100006796

Small Ring – IFP 100006461 100004097 100006464 100006797 100006797

Big Ring – IFP 100006463 100004098 100006549 100006798 100006798

Documents

MO Exposure Optics: IFP - Guide - EPFL · SMO IFP-Guide;130711uvo.Doc Uwe Vogler 20.08.2013 2/14 2. ... best choice for working processes that were running with an A - O ptics before