Fluxes and Solders Changing requirements over the last … 2017/DNT 2017 - Stannol.pdf · Fluxes...

Technology Day, 2017 September 13th

Fluxes and Solders

Changing requirements over the last decades- From Pine tree rosin to solid plasma fluxing

- From lead containing to lead-free, green sustainable solders

2017/09/13 | [email protected] | 1

2

Agenda for ABtehnik, Technology Day 2017

1 Company Introduction

2 Fluxes – how do they work?

3 Fluxes - chemical and physical requirements

4 Fluxes – ancient till today

5 Fluxes – VOC-free/Semi aqueous/Solvent based/Water washable/Plasma fluxes

6 Solders – from lead containing to lead free

7 Solders – sustainable, green electronics

SINCE 1879


QUALITY MADE IN GERMANY

• VELBERT

• SCHROBENHAUSEN


CERTIFIED


PRODUCT PORTFOLIO

SOLDERING STATIONS

SOLDER PASTES

ACCESSORIES

SOLDER BARS SOLDER WIRES FLUXES

SOLDERING IRONS


STANNOL VELBERTGERMANY


8









Time/Temperature

� During soldering processes it is necessary, that intermetallic layers are created

by diffusion processes. This is what we need to ensure to achieve a good solder

joint!

� These intermetallic layer consists of Cu6Sn5 and Cu3Sn (in this example)

Solder Joint Connection / Intermetallic layers


� Diffusion of these metal atoms is a kind of solving - not melting!

� Diffusion cannot start if oxide layers are present!

� Wikipedia: “In metallurgy, a flux (derived from Latin fluxus meaning “flow”) is a chemical

cleaning agent, flowing agent, or purifying agent. Fluxes may have more than one function at a

time. They are used in both extractive metallurgy and metal joining.”

Time/Temperature2017/07/23 | [email protected] | 10

Solder Joint Connection / Intermetallic layers

Removing of the oxide layer with a chemical reaction!

Solder

Copper

Wetting

Fluxes – properties

CuO

Cu

Solder

KupferCu

• ceramics

• solder resist

• metal oxide

• oxide free

metal surface


Wetting – Acid-Base Reaction

Acid + Metal oxide Metal salt (+ Water-(Vapour))

Adipic Acid + Tin oxide Tin adipate + Water

C4H8(COOH)

2+SnO C

4H8(COO)2Sn +H2O

Rosin acid + Tin oxide Tin rosinate

With halide containing activators first hydrochloric acid will occur (only used as an example)

1: HN(C2H5)2*HCl HN(C

2H5)2

+ HCl

2: 2 HCl + SnO SnCl2

+ H2O

T

SnO or SnO2

have to be removed by activators (for Sn based alloys, regardless if Pb is present or not). Using

lead-free alloys, the reduction/removal of the oxides can be carried out with the same chemical reaction type!

Same activators can be used for lead-free and lead containing alloys!

Different amounts! Different properties (thermal stability)!


13









Classification to standard J-STD004B : 2008

Classification

Difference to

DIN EN 61190-1-1

is only the halide

content for L1

0.15 instead of

0.5% in J-STD004


Surface Insulation resistance (SIR)

Temperature: 104°F/40°C Test time

Humidity: 93% r.H. 4-7 Days (SIR)

21 Days (E-Migration)

Test board: IPC-B-24


Flux for wave and selective soldering EF250


J-STD004 requirement (100MOhm)


Additional test methods for determining the safety

of a flux for wave and selective soldering

Acid Value / Acid rating / Acid number:

- Measures the amount of acid, which is inside

the flux. The consumption of base (here: KOH)

in mg per gram of flux will give this value.

- In general, the higher the value, the better the

flux will react and remove oxides from the

surface to be soldered

- Acid + Base = Salt + water

- can be tested with a “Mini Titration Kit”

Fluxes – physical data


1

• Voltage:13V

• Test conditions

− 2,4,6 and 8

- 131°F /55°C

and 97% rel.

humidity

− 1,3,5 and 7

- 82.4°F/ 28°C

and 97% rel.

humidity

10x

Ohm

SIR-Test – electrical reliability trials with different rosin contents


20










Pictures from Wikimedia.com

Rosin (Colophony), origin

C

CH 3

OH

O

CH 3

Abietinsäure

CH 3

OH

O

CH 3

Laevopimarsäure

CH3

OH

O

CH3

LaevopimarsäureDehydroabietinsäure

CH3

OH

O

CH3

LaevopimarsäureDehydroabietinsäureTetrahydroabietinsäure

Rosin (Colophony)

Natural Rosin from pine trees

Mix of organic rosin acids

Main component: Abietic Acid

chemically

modified

Rosin


Rosin as an activator

• Known and used for ages as a natural soldering flux

• Reacts as a weak acid with the metal oxide

• can absorb oxygen

• Is soluble in many solvents

• Insoluble in water

• Reaction products and other metal salts are soluble in rosin

• Liquid at soldering temperature (Melting range ca. 80°C)

• Chemically resistive against water

• Good Insulation properties

• Carboxylic acids are soluble in rosin

• Leave a lot of yellowish to dark brown residues

• Customers want to buy clean boards


Reason for development of No-Clean fluxes in the late 80‘s

• CFC (chlorofluorocarbons as cleaning agent) ban in the early 90‘s lead to change in manufacturing processes usage.

• With CFC cleaning of boards was easy, and eliminating this cheap and easy to use cleaning agents results in development of so called “No-Clean” fluxes

• No-Clean does not mean: There are no visible residues to see

• No-Clean describes, that remaining residues after standard soldering processes are not corrosive and are electrical safe

– Always only according to standard laboratory tests!

– If your PCBAs are operated under elevated conditions, please check always, if residues are safe to be left on the PCBA!


Liquid fluxes for wave/selective soldering

Solids Activator Solvents

Rosin

Modified Rosin

Fatty acids

Resin

Wax

Monocarboxylic acids

Dicarboxylic acids

Organic halides

Amines

Alcohol

Polyalcohol

Terpene

Ester

Ether

Glycol ether

Water

Fluxes - Composition


0%

20%

40%

60%

80%

100%

ROM0 ROM0 ORL0 ORL0 ORH0

H2O

Resin/RosinActivator

Additives

IPA Solvent

Fluxes – Composition / Ingredients


Water

27









5 main groups of fluxes, differentiation

by chemistry / used solvents

- Alcohol based fluxes

- Semi aqueous fluxes

- Water based (VOC-free) fluxes

- Fluxes with water washable residues

- Solid Fluxes for plasma application

Fluxes - Composition


Alcohol based fluxes

- Based on low boiling solvents

(Ethanol, Isopropanol (2-Propanol)

- Pro

- Well known and understood technology

- Fast evaporating of solvents prior to contact

with solder, low energy consumption in pre-heat

- Good solubility of all known activator and

additive systems

- Con

- Flammable liquid, transport, storage, handling



Semi-aqueous fluxes

- based on 40-60% water and low boiling solvents (Ethanol,

Isopropanol (2-Propanol)

- Pro

- lower flammability,

- reduction of VOC emissions

- known and long time used technology

- still fast evaporating of solvents prior to contact with

solder, lower energy consumption in pre-heat as with water

based fluxes

- Good solubility of all known activator and additive systems

- Con

- still “slightly” flammable liquid, transport, storage,

handling


Water based fluxes

- Based on 90-95% on water as the “low boiling solvent”

- Pro

- No flammability, easy storage, handling with low safety

requirements

- Reduction of VOC emissions

- Con

- Slow evaporating of solvents prior to contact with solder,

higher energy consumption in pre-heat

- Limited solubility of many well known activators and

additive systems

- Soldering equipment needs to be prepared for higher,

longer pre-heat temperature


Fluxes with water washable residues

- Can be based on water or solvents like IPA, Ethanol as the

low boiling solvent

- Pro

- High activity results in perfect soldering, often much better

then with low solids No-Clean fluxes

-Who cares about halide containing activators, if the have to

be removed anyhow?

- Con

- Residues need to be cleaned

- Water based cleaning processes need to be controlled and

supervised the same way as every other cleaning process

- Will leave corrosive residues, if cleaning is not carried out

properly!


Solid fluxes for application by plasma

- No solvents, 100% solids, only solid activators and solid

additives

- Pro

- Easy handling as crystalline powder, not flammable

- Known activators, similar to the ones used in liquid fluxes

- Reduction on 90-95% mass of flux for transport and storage

-Con

-Rosin as part of the formulation is not positive

- Creates in trials bridging and solder balls

- Not widely available , new equipment requires invest

- different fluxes for different PCB passivation surfaces required?



Selective Fluxing Unit from SEHO with integrated Plasma “burner”

Pictures from “Lösungsmittelfreier Auftrag”, SEHO 2016



Test boards after soldering

Pictures from “Lösungsmittelfreier Auftrag”, SEHO 2016

Solid fluxes for wave/selective soldering

Solids Activators- solid Solvents

Rosin

Modified Rosin

Fatty acids

Resin

Wax

Monocarboxylic acids

Dicarboxylic acids

Organic halides

Amines

Alcohol

Polyalcohol

Terpene

Ester

Ether

Glycol ether

Water

Fluxes – Composition – Plasma application

Basic formulation of acids with corrosion inhibitors for electrical safety,

but delivery form as powder needs to be controlled, shelf life ect.




- No solvents, 100% solids, only solid activators and solid additives

- Less contamination of PCB

- Less contamination between PCB and frame (no capillary effect due to absence

of solvent)

- Less contamination of flux and preheat chamber – maintenance reduced

- Activity of applied flux will remain over some time – 1 Fluxing unit for several

soldering machines?

- Cheaper process due to lower flux consumption

• Alcohol based fluxes with minor amounts of rosin give mostly the best compromise between:

– Fast evaporation of main solvents, always consider the bottleneck time/preheat at batch processes like selective soldering

• Water based fluxes: Limitations in most selective soldering units is the pre-heat. – The higher the boiling point of the used solvent, the longer it takes to get rid of it! Costs a lot of cycle time!

• Semi-aqueous fluxes– Depending on the used amount of water a good compromise between VOC emissions and required pre

heat time for evaporating the main solvent mixture

– Better 30-40% water than 50-60% for selective soldering

• Fluxes with water washable residues– If based on low boiling solvents, evaporation is fast and pre heat is not necessarily the bottleneck

– If based on water, preheat time and reachable temperature can be the process bottleneck

• Solid fluxes for plasma application– Advantage: No solvent to be evaporated! No flammable material! Shorter Preheat! Less contamination!

Fluxes for selective solderingWhich group of fluxes is used best?


Selector guide

for fluxes and all

other products on

www.stannol.de


40









• 2 main alloys Sn63 and Sn60 for cost reduction purpose, Sn62 with2% Ag for SMT

solder paste and a few speciality alloys…..and that’s it!

When life as process engineer in soldering technology was easy…


Mass-%

When life in soldering technology was easy…..

100% Sn 100% Pb

232°C MP

323°C MP

183°C

WSn WPb

Liquid

solidsolideutectic

37% Pb



• Wave soldering:

– 250-260°C solder bath temp.

– 80-120°C pre-heat

• Selective soldering



• Reflow soldering

– 205-220°C peak temperature


• Wave soldering:



• Selective soldering



• Reflow soldering

– 235-250°C peak temperature


Lead containing alloys Lead-free alloys

Summary:

Process temperature have to be increased by minimum 20K

When life as process engineer in soldering technology was easy…

??????


How to choose the optimum solder for each process?

• Always take the key data into consideration: What are the maximum process

temperatures allowed for your PCBs and components!

• Which soldering temperatures are required?

• - Which alloy is in your solder paste for reflow SMD soldering? Specified by customer?

- Which alloy is in your wave solder equipment for THT? Specified by customer?

- Which alloy is in your selective solder equipment for THT? Specified by customer?

• Strategic decision?

– All used alloys are the same to avoid any mixing or discussion with customers

• then it will be silver containing

– for each different soldering process the most cost effective solder (micro alloyed where required for technical

reasons, with or without silver, depending on thermal stability of components, process related, ect.)

• Technical requirements for solders with specific properties?


• Standard solders

– Sn99.3Cu0.7 – 227°C MP

– Sn96.5Ag3.0Cu0.5 (SAC/TSC305) 217-223°C MR

• Microalloyed solders

– Base of Sn99.3Cu0.7 – 227°C MP

• FLOWTIN TC with Co/Ni/Ce – lowest copper leaching

• SN100C with Ni/Ge – low dross formation, lower copper leaching

• A lot more special solders based on SnCu eutectic are available

– Sn96.5Ag3.0Cu0.5 – 217-223°C MR• FLOWTIN TSC305

– Pre-saturated Sn Cu solders like TC300 Sn97Cu3 for lowest copper leaching at higher process temperatures

• Flowtin TC300 for high soldering temperatures of 380-420°C



Problem: Dissolution of copper

T

Solder bath

Copper wireThermometer

Dip

Time

Dissolving a copper-wire

FLOWTIN



Co

pp

er

lea

chin

g i

n µ

m/s

ec


Enameled copper wire

time till complete dissolution

0 5

10 15 20 25 30 35

TC300 TC300FL TC300 (Sn97Cu3) - Flowtin TC300

Time /sec

0,14 mm

0,09 mm

Dissolution of enamelled copper wire @ 400°C

TC300 (Sn97Cu3) – FLOWTIN® TC300


• Important: Discuss your requirements and expectations with the technical

support of your solder supplier (hopefully us!)

• Communication is the key to identify the best solder for your processes!

• Not every soldering process can be done with one alloy

• Solders can be differentiated by

– Technical reasons like copper leaching, stability of solder bath composition

– Allowed Application temperatures

– Price – with or without silver can create price differences of 50% and more

– Long term reliability of solder joints




Selector guide for solders

and all other products on

www.stannol.de

52









THE NEW SUSTAINABILITY PROGRAM OF STANNOL

GREEN ELECTRONICS

HISTORY

DEVELOPING FAIR ELECTRONICS

2012

Nager-IT mouse: First electronics device that incorporates fair trade idea into Electronics

production and sourcing

2014

Nager-IT suggests to create fair solder

for its mouse, FairLötet is born

2015

FairLötet e.V. and STANNOL develop

solder wire that avoids not fair practice and

a lot of CO2

FIRST COMMITMENT TO SUSTAINABILITY

First fair solder wire in cooperation with FairLötet e.V.Made from recycled tin and solders

HS10 FairReleased October 2015

PURCHASING CRITERIA

Until now there were only 2 important purchasing criteria for the price of solder:

• QUALITY

High-purity primary tin for solders from Stannol

• PRICE

World market price according to the London Metal Exchange plus premium for the production and quality service

... more criteria are gaining in importance:

POTENTIAL OF IMPROVEMENT

In many mining areas are disastrous working and living

conditions due to the growing demand for raw materials

DOWNSIDE OF ELECTRONIC PRODUCTS

The environment is destroyed much more due

to uncontrolled extraction of minerals

BEYOND CONFLICT FREE

• The industry's current efforts focus on avoiding the financing of armed conflict in the Great Lakes Region, DR Congo (Dodd-Frank-Act, Section 1502)

• FAIRTIN goes far beyond being conflict free and buys tin from environmentally and socially sustainable sources

ALTERNATIVES

Ecologically and socially sustainable sources of tin

MAKE A DIFFERENCE WITH FAIRTIN

What is FAIRTIN?

For our FAIRTIN products we exclusively use tin from suppliers who …

• take care about the environment

• take social responsibility for employees and local population

• act transparently beyond the legal minimum and adhere to fair trade

MAKE A DIFFERENCE WITH FAIRTIN

TOGETHER ON THE ROAD TO FAIRER TIN

There is currently no certified fair tin mining available on an industrial scale. With Stannol as a strong partner you can start with the fairest available primary tin and participate actively in

future improvements.

THE 2 PILLARS OF OUR PRODUCT RANGE

STANNOL's well-proven product range

- Solder Bars

- Solder Wires Primary Tin

from producers who are strongly committed to employees,

society and the environment

FAIRTINTin from environmentally and socially sustainable

sources

+1.5% (0.3€/kg alloy)

NEW PRODUCTS FROM STANNOL

All of our existing lead-free products

- Solders/Alloys

- Solder wires

can be manufactured with Tin from our chosen suppliers for FairTin.

The solder and solder wire will remain the same high quality, as expected from our customers.

When using an average amount of 3g solder per double Eurocard PCBA the surchargefor using FairTin per PCBA is

0.0009 €/PCBA = 0,09 Cent/PCBA

Fairtin Surcharge for 2017 = 0.30€/kg alloy



Each customer will receive a certificate with each delivery/batch

A few words about the solder wire sample in front of you…..

New solder wire, REL0 activated - Lower spitting as current Kristall series

- Low odour, more like rosin based solder wire fluxes

- Good wetting as L0 activation

Available documents:

- Technical data sheet

- Laboratory result 1127, Reliability testing

- SDS for alloy TSC305

Kristall 600, made with Fairtin

Reliability testing passed as REL0

Copper mirror test

Copper corrosion

Kristall 600, made with Fairtin

New solder wire, REL1 activated - Extremely low flux spitting

- Recognizable odour, best to be used in automated soldering

units

- Good wetting , clear residues

Available documents:

- Technical data sheet

- Laboratory results , Reliability testing

- SDS for various alloys

Trilence 3505, made with Fairtin

TOWARDS THE FUTURE WITH STANNOL

Soldering products from STANNOL enable youto satisfy you and your customers

striving for sustainability

... with quality unchanged

Jens Gruse, Application [email protected]

+49 172 2553446

– when it´s about soldering

Any questions?

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