Impact of the Öko-Institut Recommendations on the Solder Manufacturer

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 • Including non-solder EEE materials

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 Solvent blend Resins (hydrocarbon and rosin derivatives) Plasticisers Acid & amine activators Halogen activators Wetting agents Rheology modifiers …….. Sn Pb Ag Cu Sb Bi Ni …….. 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) • Wide choice of suitable materials no impact • 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 • Wide choice of suitable materials no impact

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