1. Impact of the Öko-Institut Recommendations on the Solder Manufacturer
Malcolm Warwick

2. Scope of the Presentation
Introductory Comments
Major generic components of solder products
Focus on Issues raised by the Öko-Institut recommendations
Organobromine compounds
Phthalates
Including non-solder EEE materials
Nonyl phenol & ethoxylate

3. Introductory Comments
The views expressed are the author’s personal perspective of the potential impact of the recommendations on materials used in EEE
The technical information is non-proprietary and is believed to be representative of materials produced by Henkel and major competitors

4. Drivers at Henkel for Eliminating Materials from EEE
Legislation
(International, Regional, National)
Technical Information
Customer & Industry Requirements
Internal Henkel Sustainability Policy
Re-formulation
Product Elimination
Henkel policy can be ahead of legal requirements

5. Solder Products in EEE
The Assembler uses solder products to create interconnections
Electrical continuity
Thermal pathway
Hermetic seal
Mechanical integrity………..
The solder interconnection in the EEE contains
The solder alloy
All the elements from the original solder product + elements from metallisation layers
The residues of the flux system
In some applications these are removed by the Assembler
The residues contain most of the original flux components + some metal salts

6. Generic Solder Product Raw Materials
Combinations of elements provide UNIQUE property sets. Substitution of one component causes a complete technology shift
Sn Pb
Ag Cu
Sb Bi
Ni ……..
Solvent blend
Resins (hydrocarbon and rosin derivatives)
Plasticisers Acid & amine activators
Halogen activators Wetting agents
Rheology modifiers ……..
Alloy
Flux
Flux Paste
Wire
Flux Cored Wire
Solder Paste
Bar
Liquid Flux
Spheres

7. RoHS Proposals and Generic Solder Fluxes
Solvent blend
Wide choice of suitable materials no impact
Resins (hydrocarbon)
Resins (rosin derivatives)
Critical component of fluxes and complete substitution not possible no impact with current proposals
Plasticisers
Choice of suitable materials legacy products contain phthalates
Acid and amine activators
Carboxylic acids no impact
Halogen activators potential major impact
Wetting agents
Choice of suitable materials legacy products contain NPE or similar
Rheology modifiers

8. Halogen Compounds & EEE Solder Fluxes
The critical step in the soldering process is cleaning the metal surfaces to allow direct metal-metal contact
Halogens are highly effective at disrupting oxide films on solder and metal surfaces to be joined
Used at relatively low concentrations (≤3% of flux)
Flux ≤10% of the weight of solder associated with a joint
A typical mobile phone carries ~100μg halogen in the flux residues
Other activators (acids, amines) dissolve oxides
This can be too slow to compete with re-oxidation during the soldering process (up to 260°C)
The quantity of other activators that can be used is limited in solder pastes because of product stability
Halogens can be formulated into EEE fluxes as inorganic or organo-halogen compounds

9. Halogen Flux Chemicals
Inorganic halogen flux components are an immediate source of “halide” for oxide removal
Tend to be used today in flux cored wire and more active solder pastes
Unused halide in the flux residues is often considered undesirable by Assemblers (electrical reliability)
Organo-halogen flux components may interact directly as flux agents but also release halogen (halide) during the soldering process
Tend to be used today in most solder pastes
Unused organo-halogen in the flux residues is often considered less problematic than halide residues
Both classes of chemical will leave halogen compounds in flux residues

10. Consequences of Eliminating Organo-Halogen from EEE Fluxes
Truly Halogen-free formulations exist today
Some formulations are called “halide-free” based on specific industry test methods
Generally, omitting halogen from the flux severely reduces the product process window
Particularly for Pb-free soldering
Particularly for solder paste
The impact for EEE manufacturers
Increases the incentive to use inert (nitrogen) process atmospheres
Increases EEE manufacturing costs
Increased process control
Increased solder product scrap

11. Halogen Compounds & Other EEE Production Materials
High value/high specification EEE Materials use base thermoset resins which have low halogen content
A large amount of base thermoset resin containing adventitious halogen is used for less demanding EEE applications
e g for potting/encapsulation processes
The most commonly used Bis-A resins average ~1500ppm chloride
Higher levels tend to be in more flexible long chain grades
Some of these resins are available with low halide
At x2 – x4 cost impact
Some of these resins are not available in low halide versions

12. Phthalates & EEE Solder Fluxes
Legacy solder products contain phthalates
Used to plasticise resins (rosins) to improve flow and stability during soldering processes
Used as very high boiling point liquids
Good thermal stability
Do not interfere in the chemical functions of a soldering flux
Alternative high boiling solvents, waxes, & rosin esters can perform a similar function
Barrier to implementation is the cost of re-formulation and customer approval processes

13. Phthalates & Other EEE Production Materials
Phthalate compounds are used as non-reactive modifiers to plasticise polyurethane EEE potting materials
Up to 50% in some formulations
Offer a unique combination of physical properties and cost
Alternative plasticisers are un-proven in EEE potting applications
Customer approval cycles will be long and difficult

14. NP(E) & EEE Solder Fluxes
NP(E) and other alkylphenol(ethoxylates) have been used as general wetting agents
Present in some legacy products
Alternative materials generally fit-for-purpose

15. NP(E) & Other EEE Production Materials
NP is used in the manufacture of epoxy-based EEE potting materials
Provide a unique combination of properties and cost
Cure/Strength combination is not matched by alternative systems commercially available
NP is incorporated into the final cure matrix as it appears in finished EEE
Availability for leaching is low but product/application specific

16. General Conclusions for EEE Solder Products
Apart from re-formulation/re-approval of some legacy products, most of the recommendations have no impact
Industry has already taken note of the issues surrounding some of the materials and taken pre-emptive action to remove them
Flame retardants are not used in solder products but the recommendation to eliminate general organo-halogen compounds from EEE materials needs further consideration
Organo-halogen compounds are valuable fluxing agents
Alternatives are technically much less effective
Base resins for EEE materials (not solder products) contain halogen at levels likely to be above a RoHS threshold