clean production in an industrial environment

Clean production in an industrial environment

Anton de Jong, Anton Duisterwinkel

2011-03-11

Themadag Schoon Produceren

1

CONTENTS

1. Introduction

2. Systematic approach of assessing risks

3. Contamination control

- Prevention

- Cleaning

- Detection and Qualification

2011-03-11


2

Why bother?

Cleanliness becomes more important for the High Tech industry, e.g.

Semiconductor (ASML, ASMI, supply chains)

Analytical instruments, mass flow controllers of Bronkhorst; FEI

Automotive (Nedcar, etc.)

Medical

Space (ESA, NASA)

Solar

Lighting (OLED’s), electronics

Important:

How to produce cleanly in a cost effective way

How to check the quality of products

Essential: keep the balance between costs of risks and the

costs that control of the risks will bring

2011-03-11


3

Clean production of high tech products

Product Company cleaniliness Remark

particles organic outgassing

cont. vacuum

Analytical flowmeters Bronkhorst yes yes no oxygen safety

(EUV) Lithography ASML yes yes yes optical performance

Electron Microscopy FEI yes yes yes opitcal performance

Space instruments TNO Space, ESA yes yes yes optical performance

Solar cell prodution OTB,….. yes yes no/yes yield, lifetime

OLED, OPV Holst yes yes no/yes yield, lifetime

2011-03-11


4

Contaminants: what and where from?

Object surface

Films

Oil, grease (production), Food, Biofilms

Molecular

Water (condensate), Hydrocarbons (air), NH3, silicones (production)

Particles

Organic particles (pollen, micro-organisms, hairs, fibers, …, > 1 µm)

Metallic particles (due to production, abrasion, ageing, > 1 µm)

Oxidic: Sand, dirt, asbestos (environment, glass treatment, abrasion)

Soot/smoke, salt, (NH4)2SO4 (condensation: < 1 µm)

2011-03-11


5

Cleanliness: does it exist?

Example 1: Oxygen application;

maximum concentration organic material (< 66 mg C/m2)

Example 2: Clean surface in food industry, allowed number of colony’s?

2.5 CFU/cm2, or 25000 per square meter!

Example 3: Clean assembly: ISO Class 4, allowed number of particles?

10000/m3 (of 0.1 µm or larger);

352/m3 (of 0.5 µm or larger)

‘Dirty’, but fit for purpose !

2011-03-11


6

Clean is dirty …

to the extent that functionality is not hindered.

Rule 1 ‘Clean must defined’- Typically: no gross (visual) contamination- Definitions on particles (size, number) and molecules

Rule 2 Testing method must be defined- who and when determined- exact description of method

Rule 3 Responsibility, liability must be defined

What is clean?

2011-03-11


7

CONTENTS

1. Introduction



- Prevention

- Cleaning


2011-03-11


8

Systematic approach for contamination control:

1. Products and production scheme

2. Assessment of the risks (FMEA)

3. Solving of the most important risks

Example:

Product : example complex assy

QD1:

Mat. Cer.

QD1:

Mat. Cer.

QD1:

Mat. Cer. 028 t=..

Weld water

hoses to

cooler body

001

Material for

cooler body

003 t=..

Milling002

fQ

004, t=..

Intermediate

Wet clean

007 t=..

Store

QD1:

Mat. Cer.

023

Water Hose 024

fQ

026, t=..

Intermediate

Wet clean

027 t=..

Store

QD1:

Mat. Cer.

029

Filament 030

fQ

032, t=..

Intermediate

Wet clean

033 t=..

Store

QD1:

Mat. Cer.

035

Screws 036

fQ

038, t=..

Intermediate

Wet clean

039 t=..

Store

041

Vac. Bolts 042

fQ

044, t=..

Intermediate

Wet clean

008 t=..

Intermediate

Wet clean

001

Material for

backplate

002

fQ

003 t=..

Milling004, t=..

Intermediate

Wet clean

t=..

Transport to

Louwers

005 t=..

Melt in

electrical

feedthroughs

002

lfeedthrough

s

t=..

Transport to

A

004, t=..

Intermediate

Wet clean

002

Gas hoses

005 t=..

Weld gas

hoses to

backplate

002

Press

008 t=..

Intermediate

Wet clean

t=..

Transport to

T

Supplier: B

T = ..

Supplier: B

T = ..

Supplier: C

T = ..

Supplier: A

T = ..

Supplier: D

T = ..

Supplier: A

T = ..

2011-03-11


9

What kind of product?

Simple mono part

Simple assembly wet cleanable

Assembly not wet cleanable

Complex assembly sensitive not wet cleanable and sensitive to heat

2011-03-11


10

Step 1: Product /production analyses

Goal: Define the how “dirty/clean” the (end)product may be in the

different production steps.

1. Describe the product and production steps

2. Describe the requirements to the end product and the intermediate

steps

3. Define where contamination is critical for the next step in the

process

4. Define the contamination sources in the process

2011-03-11


11

Strategy for the control of a production process

• Choice and sequence of the production steps

• Detail for the production steps

Example:


QD1:

Mat. Cer.

QD1:

Mat. Cer.

QD1:

Mat. Cer. 028 t=..

Weld water

hoses to

cooler body

001

Material for

cooler body

003 t=..

Milling002

fQ

004, t=..

Intermediate

Wet clean

007 t=..

Store

QD1:

Mat. Cer.

023

Water Hose 024

fQ

026, t=..

Intermediate

Wet clean

027 t=..

Store

QD1:

Mat. Cer.

029

Filament 030

fQ

032, t=..

Intermediate

Wet clean

033 t=..

Store

QD1:

Mat. Cer.

035

Screws 036

fQ

038, t=..

Intermediate

Wet clean

039 t=..

Store

041

Vac. Bolts 042

fQ

044, t=..

Intermediate

Wet clean

008 t=..

Intermediate

Wet clean

001

Material for

backplate

002

fQ

003 t=..

Milling004, t=..

Intermediate

Wet clean

t=..

Transport to

Louwers

005 t=..

Melt in

electrical

feedthroughs

002

lfeedthrough

s

t=..

Transport to

A

004, t=..

Intermediate

Wet clean

002

Gas hoses

005 t=..

Weld gas

hoses to

backplate

002

Press

008 t=..

Intermediate

Wet clean

t=..

Transport to

T

Supplier: B

T = ..

Supplier: B

T = ..

Supplier: C

T = ..

Supplier: A

T = ..

Supplier: D

T = ..

Supplier: A

T = ..

B

Example:


QD1:

Mat. Cer.

QD1:

Mat. Cer.

QD1:

Mat. Cer. 028 t=..

Weld water

hoses to

cooler body

001

Material for

cooler body

003 t=..

Milling002

fQ

004, t=..

Intermediate

Wet clean

007 t=..

Store

QD1:

Mat. Cer.

023

Water Hose 024

fQ

026, t=..

Intermediate

Wet clean

027 t=..

Store

QD1:

Mat. Cer.

029

Filament 030

fQ

032, t=..

Intermediate

Wet clean

033 t=..

Store

QD1:

Mat. Cer.

035

Screws 036

fQ

038, t=..

Intermediate

Wet clean

039 t=..

Store

041

Vac. Bolts 042

fQ

044, t=..

Intermediate

Wet clean

008 t=..

Intermediate

Wet clean

001

Material for

backplate

002

fQ

003 t=..

Milling004, t=..

Intermediate

Wet clean

t=..

Transport to

Louwers

005 t=..

Melt in

electrical

feedthroughs

002

lfeedthrough

s

t=..

Transport to

A

004, t=..

Intermediate

Wet clean

002

Gas hoses

005 t=..

Weld gas

hoses to

backplate

002

Press

008 t=..

Intermediate

Wet clean

t=..

Transport to

T

Supplier: B

T = ..

Supplier: B

T = ..

Supplier: C

T = ..

Supplier: A

T = ..

Supplier: D

T = ..

Supplier: A

T = ..

B

2011-03-11


12

Failure Mode Effect Analysis

Step 2: Make a list of all failure modes

1. Severity � How big is the negative effect

(Higher score if it is more severe)

2. Occurrence � How often does is happen

(Higher score with increasing frequency)

3. Detection/prevention � How difficult is it to detect the failure

(Higher score if it is more difficult to detect)

2011-03-11


13

FMEA (2)

FMEA score Ernst Voorkomen Detectie

1 geen nooit zeker

2

1

minimale gevolgen voor product (alleen kritische klanten) vrijwel nooit

zeer waarschijnlijk

3 minimale gevolgen voor product (50 % van klanten) laag waarschijnlijk

4

2 gemiddelde gevolgen voor product af en toe boven gemiddeld

5 grote gevolgen voor product met tussenposen gemiddeld

6

3

kleine schade aan productieapparatuur regelmatig laag

7 schade aan productieapparatuur erg regelmatig erg laag

8

4

grote schade aan productieapparatuur vaak onwaarschijnlijk

9 wettelijke normen erg vaak zeer onwaarschijnlijk

10

5 mensveiligheid extreem vaak niet mogelijk

2011-03-11


14

FMEA (3)

Calculate the “Risk Priority Number” for each failure mode

RPN = effect x occurrence x Detection

Sort on RPN

Example:

Failure mode severity occurance detection RPN

failure in cleaning unit 10 3 8 240

failure in contamination verification 8 2 9 144

delivery of dirty tubing 3 2 9 54

fingerprints on product 2 4 3 24

FM4

FM5

2011-03-11


15

CONTENTS

1. Introduction



- Prevention

- Cleaning


2011-03-11


16

Solving the risks: Contamination control

Is a systematic effort to control contamination to such a level that it

does not disrupt functionality of a process or product by

Prevention

Clean design some major principles

Clean environment this afternoon

Clean assembly this lecture

Cleaning

Overview details this afternoon

Detection and Inspection

Detection (lab) NOT

Inspection (fab) this lecture

2011-03-11


17

Contamination control: Prevention

1. Design rules

Source controlClean in (checked!); filtering; easy to clean oils etcetera

Design of instruments and processes

Accessibility; flow away from critical surfaces; hanging

Materials selection and development(electro)polished materials; controlled contacts; non-stick coating

Optimization of process conditionsAdd chemicals that remove dirt; prevent hot spots

2011-03-11


18


2. Clean environment

Separate from normal production area

Closed room where only qualified personnel can enter

Cleanroom necessary for very critical parts only

For packaging of critical parts: clean bench or flow bench

Hang overcoats and gloves near the entrance door.

Place extra gloves boxes near baths and clean bench.

2011-03-11


19


3. Clean assembly

Control the cleanliness of incoming materials and parts:

Clean raw materials like bar, rod and profiles

before processing

Plastics will have oily residues, silicones and

plasticizers on the surface from manufacturing

All third party components must be qualified,

even if they are claimed to be ‘clean’

2011-03-11


20


3. Clean assembly

Manufacturing of components by machining:

Do not use oil based cutting fluids or use vegetable oils

Use separate tools for manufacturing especially cleaned for vacuum

All surfaces must be machined

Last machining step preferably dry or with ethanol or IPA as cutting fluid

prevents burial of cutting fluid in surface

Clean the parts in the same run

Beware of explosion risk and human safety!

After machining immediately blow off with nitrogen or dry, pressurized, oil

free air for removal of excessive cutting fluid.

Wipe parts with lint free cloth soaked with ethanol or IPA

Store under clean conditions for future cleaning

2011-03-11


21


3. Clean assembly

Clean Handling of clean parts

Handling of objects only by qualified personnel

Always wear overcoat and clean gloves (powder free!)

Limit touching of the part to a minimum.

After contact with contaminated objects put new gloves on.

Do not hesitate to change your gloves if you suspect they got

contaminated, it can save you a lot of work!

Make sure extra gloves are available

Put clean objects in a clean bench on aluminium foil

Use a flow bench to briefly store clean objects in

Package clean objects ASAP

Do not cough or sneeze above (clean) objects

2011-03-11


22

Contamination control: Cleaning

1. Strategy: Step by step cleaning

Preclean

Removes film, visible dirt, gross contamination

Can be manual, industrial dish washer is preferred

Particle removal

Removes particles and droplets to required level

Often involves wet cleaning, ultrasonic

Rinsing is critical.

Molecular cleaningRemoves last molecules,

Drives off absorbed contaminants

Preferably done shortly before use

2011-03-11


23


1. Strategy: Cleaning strategy per material

Metals can tolerate most cleaning methods

Alkaline detergents can etch or stain aluminium

Glasses are vulnerable for micro-cracking caused by

ultrasonic agitation or etching by surfactants

Plastics are sensitive to solvents and might change

their properties (tacky surface or swelling)

Ceramics are often porous and can contain large

amounts of water: baking after cleaning necessary!

2011-03-11


24


2. Cleaning methods: precleaning

to remove visible dirt and oily residues, prevent clogging

Wiping

+ standard, no investment; - no control, labour intensive

Solvent and vapour degreasing

+ good for high volume - environment, k€

Industrial dish washer

+ well controlled - (k€)

Ultrasonics

+ standard, well controlled - k€, needs supervision

2011-03-11


25


2. Cleaning methods: particle removal

to remove all particles larger than a specified size

Ultrasonics usually good

New methods for submicrometer particlesMegasonics; CO2-snow; Nano-spray

1,0E-10

1,0E-09

1,0E-08

1,0E-07

1,0E-06

1,0E-05

1,0E-04

0,01 0,1 1 10 100 1000

Particle diameter [micrometer]

Forc

e [N

] capillary

VanderWaals

electrostatic gravity

Small = hard to remove

Binding force is smaller BUT• Removal force = even smaller

• Particles hide in roughness

• Boundary layer

2011-03-11


26


3. Cleaning methods: molecular cleaning

To remove molecules to specified outgassing rate or coverage

Baking in/of vacuum system + standard, proven; - high T, low P

Plasma+ relatively cool; quick - low P, crevices

Solvent and vapour degreasing+ good for high volume - environment, k€

UV-ozon (optical components)+ low T, 1 bar, quick - line of sight, O3

2011-03-11


27


4. After cleaning: packaging

Package a part as soon as is has reached room temperature

Always check if components are clean

Pack the objects in a clean bench or a flow bench

Touch the clean objects only with clean, non-powdered gloves

Seal the package and mark it with ‘clean parts’.

Package in layers

Aluminium foil (clean, getter, but may smear)

Plastic bags (clean, easy, may outgas)

Casing or box for physical protection during shipping

2011-03-11


28

Contamination control: Inspection

1. Pragmatic monitoring methods: non contact

Direct inspection

Compare to clean surface

Use strong and stable lighting and a binocular

Also inspect at grazing incidence

Black light (purpose built UV-source)

Will show up fluorescent contaminants

Use protective glasses, aim at surface only

Darken the room

Fluorescence

Will show up fluorescent contaminants, e.g. oils

Need to scan the surface

2011-03-11


29


2. Pragmatic monitoring methods: contacting methods for particles

Wiping (white glove, white towel)

Wipe form clean to dirty

Compare to non-used glove or towel

Use strong and stable lighting, fiber optics

Tape test

Press transparent tape on object

Carefully remove and place on white paper

Compare tape to white paper

2011-03-11


30


3. Pragmatic monitoring methods: contacting methods for greasiness

Water break test (ASTM Method F 22-26)Observes hydrophobic contaminants only

Breathing or atomizing is better alternative

Use contact angle measurements for qualification

Atomizer testGently spray deionized water over the surface

Observe whether droplets are deposited uniformly

Non-uniform spots due to hydrophobic contaminants

Contact angle measurementsSessile drop technique is preferred. Use DI-water

Semi-automized equipment is available (10-20 k€)

Sensitive to less than monolayer contamination

Water drop testPlace drop of 0.2 ml DI-water on surface.

Determine surface area (diameter) after standard time

Smaller = more hydrophobic = dirtier

2011-03-11


31


4. Strategy for qualification of parts and assemblies

1. Set clear requirements with clientType of contaminant (gross, particle, grease, …)

Method for measurement (suitable for type of contaminant)

Maximum acceptable value (that can be determined by that method)

2. Develop clean production method (= handling, cleaning, packaging) Test with selected method

Optimize production process; document this

Train and coach the staff (this is an ongoing activity)

3. Ensure clean supply lineQualify your suppliers on quality control,

validated procedures, staff training and

coaching, supply chain, facilities

4. Perform regular tests All assemblies

functional test

All pieces

practical test

Critical

Random sampling

functional test

Random sampling

practical test

Non-

critical

AssembliesParts

2011-03-11


32

Conclusion

clean production in an industrial environment

Documents

feedthroughs backplate

themadag schoon producerenstep

clean assembly

wet clean029

clean surface

clean productionin

cooler body fq wet clean

production process example