BUEE 2013 AMC countermeasure in - SEMI.ORG | Gall_M...BUEE 2013 AMC countermeasure in M+W High Tech...

BUEE 2013AMC countermeasure in

future high tech FabsM+W High Tech Projects Taiwan Co., Ltd.A Company of the M+W GroupNovember 29th, 2013 – Michael Gall

© M+W Group

AMC- countermeasure in future Fabs

1. AMC definitions & specificationsa) Definition according SEMI F21-95

b) Relevant industries

c) Specification of concentration limits / ITRS

d) Critical processes & AMC impact

2. AMC countermeasuresa) Prevention

b) Separation

c) AMC Filtration

3. AMC filter concept for future Fabs1. Impact of efficiency & capacity

2. Regeneration & waste reduction

© M+W Group3

Short introduction to AMC?

� AMC means Airborne Molecular Contamination

� International classification according to SEMI F21-95

A Acid (SO2, HCl, HF, Nitrogen oxides NOx,….)

B Base (NH3, Amines…)

C Condesables (Volatile Organic Compounds = VOC)

D Dopant (Phosphorus and boron compounds)

= Chemical element which even as trace part can modify the electrical proprieties of a semiconductive material)

� A fifth category is currently being introduced into the practice of contamination control

�„Refractories“ (Organic substances except CHON compounds)

like Si (Siloxanes), S, P …

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Categories of AMC and typical compounds (SEMI F21-95)

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AMC - Market Overview

AMC –high importance

SemiconductorHard disc Flat Panel

AMC – low importance(Current situation)

PV fabsPharmacy

Medicaltechnology

Nanotechnology

Food fabs

� Transistor technology with more and more thinner layers => the most vulnerable target for air contamination

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AMC – specification of concentration limits

� According different process AMC sensitivity and different process setup there are no general specification of AMC limits in cleanroom

� Most semiconductor companies define their cleanroom concentration on their own.

� As recommendation values the International Technology Roadmap for Semiconductor (ITRS) can be taken. Their values are updated regularly, current version is 2011 ( 2012 just update version, 2013 not yet released)

� According latest ITRS, AMC specification levels will not have big changes in future

� New processes (like EUV) will have more AMC requirement in future but unlikely will influence Fab design

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AMC Impacts, Risks and Specifications - Overview

AMC Classes Damaging mechanisms Sensitive ProcessesRiskClasses

RecommendedSpecifications 1)

[µg/m³]

Photomask exposure (Mask room) 1 10

Metrology 1 10

Lithography 1 10

CMP 5 2

Open metal- and copper processes 3 2


Metrology 1 5

Lithography 1 5

CMP 5 5


Metrology 1 150

Lithography 1 150

Gate-Oxide /High temperature furnace 4 150

DDopants (as hexadecane)

▪ Modifying of the electrical properties by uncontrolled Doping

Gate-Oxide /High temperature furnace 4 0,1

Lithography 1 1

Metrology 1 1

Risk class: 1 - 5, high lo low

n.A. = not applicable

1) = according to the specifications of tool suppliers and ITRS road map, respective

▪ Haze generation in generally and especially on critical optical laser parts

Refractory's (as Hexadecane)

▪ Nanoparticle haze generation on critical optical laser parts, particularly at middle and high molar mass

▪ GOI (Gate oxide integrity)

CTotal VOC (Organic compounds, retention time GCMS ≥ Benzene,calibrated as Hexadecane)

BTotal bases (as ammonia)

▪ Particle generation

▪ T-Topping

▪ Nanoparticle haze generation on critical optical laser parts

▪ Corrosion

▪ Nanoparticle haze generation

ATotal acids incl. org. acids (as SO2)

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Extract ITRS Roadmap 2011 - Lithography

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Extract ITRS Roadmap 2011 – Reticle /Gate Furnace

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Typical Concentration Ranges in Cleanroom

Summary by M+W group experience in different projects:

Conclusion:

- very different concentrationsfor sensitive and “general” areas

- To be considered at the designof the air flow system(not all areas need the same strong filtration)

Reported damage in general areas

smell

ng/m 3 µg/m 3 mg/m 3 g/m 3

Acids

Bases

Condensables

Dopants smell

smell

smell

smell

Refractories smell

Reported damage in sensitive areas

Values in cleanroom and in the outside air are hatched

Spec

Spec

Spec

Spec

Spec

© M+W Group







b) Separation

c) AMC Filtration



© M+W Group12

Sources of AMC

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AMC countermeasure – prevention

� Most effective way is to reduce AMC contamination is to prevent the contamination by knowing and controlling the sources.

� Not existing AMC contamination don't need to be purged / filtered

� Some AMC (e.g. low boiling) are easy to purge or dilute but difficult to filter

� Some AMC (e.g. high boiling, surface sticking AMC) are very difficult to clean up and will be a long term AMC source while operation.

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AMC – prevention – design & construction Phase

� AMC contamination should be considered:

� from the very beginning of Fab design� Scrubber & Exhaust design

� efficiency

� stack height

� location

� Construction material choice� Approve outgassing behavior

� Construction phase� Sufficient venting of outgassing material,

� Income check (e.g. with ppbRAE)

� Fab purging

� Control manpower

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AMC prevention - separation

� Unlike Particle movement, AMC contamination can move vertical or even against airflow direction. Any contamination easily can impact other process areas even there is some distance in between

� Similar AMC sensitive processes should be located at same place and equipped with certain AMC filter setup

� These areas should be separated in cleanroom, subfab and truss area in order to avoid mixing of different AMC air qualities

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AMC – prevention – operation phase

� Internal source control� Right exhaust adjustment – avoid AMC contamination from process chemicals

� Move in material check (outgassing issue)

� Prevent leakage, spills while maintenance

� Online AMC monitoring for fast emergency response

� AMC filters

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AMC filtration

� Even source control will reduce contamination levels end extend AMC filter lifetime, the usage of AMC filters will be necessary

� AMC filters can be designed for one single contamination type or for several contamination types. However. Each AMC type needs special AMC filter media

� AMC filters are available in different shapes for different usage area.

� Most common types are used in � MAU and

� In the recirculation air

� Combined or integrated in process tools

� Combined or integrated in supply tools (e.g. compressors, vacuum pumps)

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Available AMC filtration Technologies:

SAC… Strong acid cation exchangerWAC… Weak acid cation exchangerSBA… Strong base anion exchangerWBA… Weak base anion exchanger

Unimpregnated carbon

Impregnated carbon

WAC/WBA SAC/SBA

Removal efficiency + + ++ ++

Removal capacity + ++ ++ +

Desorption behaviour

low boiling VOC + + ++

Organics Inorganics (Acids & Bases)

Adsorption Chemisorption Ion exchange

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Air washer

AMC – filtration outside sources

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Typical AMC filter efficiency:

~ 90%

Typical Air washer efficiency:

~ 90%

Typical MAU outlet conc.:

Bases < 1ppbAcids < 1ppbTOC < 10ppb

Airflow direction

� Outside air control

� Avoid shortcut with Fab exhaust

� MAU include air washer + AMC filtration steps

© M+W Group

AMC filter installation possibilities

TT

HH

PPControl Panel

ProcessEquipment

Subfab

Scanner

TTHHP

Return AirFilters

CDAFilters

FFUFilters

ToolmountedFilters

Makeup AirFilters

MinienvironmentFilters

PControl Panel

ProcessEquipment

XCDA

Scanner

Cleanroom

Compressor

Makeup AirMakeup Air Unit

TT

HH

PPControl Panel

ProcessEquipment

Subfab

Scanner

TTHHP

TT

HH

PPControl Panel

ProcessEquipment

Subfab

Scanner

TTHHP

Return AirFilters

CDAFilters

FFUFilters

ToolmountedFilters

Makeup AirFilters

MinienvironmentFilters

PControl Panel

ProcessEquipment

XCDA

Scanner

PControl Panel

ProcessEquipment

XCDA

Scanner

CleanroomCleanroom

Compressor

Makeup AirMakeup Air Unit

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© M+W Group

AMC filters – type overview

MAU Type� V- shape

� Cylinder / Cartridge shape

FFU / Tool type� Box type

� Modular frame type

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AMC concept for future Fabs

� In general there will not be a big change in Fab design between 300mm and 450mm technology, therefore the general AMC setup also will not change.

� Smaller structures will lead to more AMC sensitivity, this will also impact AMC cleanroom specification limits even not yet seen in ITRS roadmap so far.

� Lower AMC specification limits will soon require new media since adsorption at sub ppb level and desorption phenomenon will limit current medias.

� Most material with high efficiency (> 95%) will not have a very high capacity. This will probably lead to a 2 stage AMC filtration:

� 1st stage: one high capacity filters

� 2nd stage: high efficiency filters

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AMC filters – usage method

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� AMC filters just have a limited lifetime in between 3 month and 24 month depend on inlet concentration and efficiency specification

� AMC filter weight is in between 10kg and 25kg

� So using AMC filters just one time will cause a high amount of waste that has to be considered as chemical waste

� Depend on AMC filter media and design some be regenerated.

� M+W group has more than 5 years experience in regenerating TOC, ammonia and acid filters already.

� Some filters already have been regenerated for 8 times with a total filter usage time of 5 more than 5 years

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Summary

� AMC reduction by 3 main countermeasures:

� Prevention

� Separation

� Filtration

� For future high tech Fabs all AMC sources need to be controlled

� Outside sources � Air washer + AMC filters

� Inside sources � material control + process control + AMC filters

� Most types of AMC already AMC filter solutions available

� Lower AMC cleanroom specification will lead too more AMC filter stages and more AMC filtration locations � increase of AMC filter usage

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© M+W Group27

Thank You

Contact:Michael GallAMC Managere-mail: [email protected] +886 3 542 1415 – 2415, Mobile +886 988 509 935www.mwgroup.net

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