2ª MENÇÃO HONROSA (OE) – DIA MUNDIAL DOS MATERIAIS 2007

 

Lead-free soldering processes in the electronic industry – industrial implementation at SMES

 

Rolim do Carmo¹, Margarida Pinto¹, Rogério Colaço², Dag Andersson³

 

¹ Instituto de Soldadura e Qualidade (rdcarmo@isq.pt; mmpinto@isq.pt)

² Instituto Superior Técnico (rogerio.colaco@ist.utl.pt)

³ IVF - Industrial Research and Development Corporation (dag.andersson@ivf.se)

 

 

ABSTRACT: Following the implementation of the new European environmental directives, Restriction of the Use of Certain Hazardous Substances (RoHS) and Waste Electrical and Electronic Equipment (WEEE), which involve the ban of lead from electronic and electrical products, this work presents process development work, production and reliability testing of real products from several electric and electronic assemblers using lead-free commercial solders that have been tested and monitored to ensure the reliability of the final products. The results were compared with the ones using tin/lead solders, in terms of performance and reliability of the joints obtained. This work aims to help the implementation of the lead-free solders in the soldering processes and supply the SMEs more information about real products and conditions that might be compared with theirs.

The reliability tests and characterisation of the real products from several companies showed that the lead-free boards demonstrated a good performance under testing, being equivalent or better than the tin/lead ones. The defects or anomalies found in most of the joints (voiding and pad lifting) result from the manufacturing process. Most of the defects were found in through-hole devices and were due to component failures and not from the joint integrity. The degradation after the reliability tests of both types of solders is similar.

The SMEs are engaged in taking this opportunity to reach a higher quality performance level in their processes. Some of the companies embraced this “forced” transition to upgrade and improve their process and facilities, bringing better capabilities and opportunities to their businesses.

The objective of this work aims to be a tool of information to the SMEs of the electrical and electronic sector, in order to help them in the transition to lead-free soldering.

Keywords: Lead-free solder, Soldering, Electronics, Reliability, PCB, RoHS.

 

RESUMO: No decorrer da implementação das recentes directivas ambientais Europeias: Restrição do Uso de Substâncias Perigosas (RUSP) e Resíduos de Equipamentos Eléctricos e Electrónicos (REEE) surge a proibição do uso de chumbo em produtos eléctricos e electrónicos. Este trabalho apresenta o estudo de desenvolvimento de processo, produção e testes de fiabilidade em produtos reais de diversas empresas do sector eléctrico e electrónico. Vários tipos de soldas comerciais foram usadas e testadas de modo a permitir a comparação em termos de performance das soldas sem chumbo face às com chumbo. O presente trabalho tem como objectivo o apoio às PMEs (Pequenas e Médias Empresas) durante a implementação da soldadura sem chumbo nos seus processos industriais e fornecer-lhes mais informação sobre produtos reais que lhes permita comparar com a sua própria produção.

Os testes de fiabilidade e a caracterização feita nos produtos em estudo demonstraram que as placas soldadas sem chumbo possuem uma boa performance em teste e são equivalentes ou superiores às placas soldadas com soldas com chumbo. Os defeitos e anomalias encontradas nas juntas soldadas resultam, essencialmente, do processo de fabrico e não das pastas e soldas utilizadas. Na sua maioria, as falhas encontradas nas placas são devidas a falha de componentes e não da integridade das juntas. A degradação das soldas após teste é similar nos dois tipos de solda.

As PMEs estão motivadas em aproveitar esta transição “forçada” para melhorar as suas capacidades, equipamentos, processo e oportunidades de negócio.

O objectivo final deste trabalho é fornecer informação às PMEs do sector eléctrico e electrónico, de modo a apoiar a sua transição para a soldadura sem chumbo.

Palavras chave: Solda sem chumbo, Soldadura, Electrónica, Fiabilidade, PCB, RUSP.

 

Texto completo disponível apenas em PDF.

Full text only available in PDF format.

 

REFERENCES

[1] Directive 2002/95/EC of the European Parliament and of the Council of 27 January 2003 on the Restriction of the use of Certain Hazardous Substances in Electrical and Electronic Equipment.

[2] Department for Business, Enterprise and Regulatory Reform. www.berr.gov.uk

[3] Directive 2002/96/EC of the European Parliament and of the Council of 27 January 2003 on waste Electrical and Electronic Equipment.

[4] “Transposition of the WEEE and RoHS Directives in other EU member states”; Government and Legislative Affairs Consultants – Perchards; 2005.

[5] WEEE Registration and Compliance. www.weeeregistration.com

[6] European Commission Funded Project – LEADOUT. www.leadoutproject.com

[7] J. Oliveira Santos, L. Quintino; “Processos de Soldadura”; Instituto de Soldadura e Qualidade; 1998.        [ Links ]

[8] R. Klein Wassink; “Soldering in Electronics”; Electrochemical Publications; 1989

[9] B. Willis; “Introductory Printed Board Assembly Guide for Lead-Free Assembly”.

[10] S. Kang; “Microstructure and mechanical properties of lead-free solders and solder joints used in microelectronic applications”; IBM J. Res & Dev.; Vol. 49; No. 4/5; 2005.

[11] J. Hwang; “Environment-Friendly Electronics: Lead-Free Technology”; Electrochemical Publications Ltd; 2001.

[12] P.Villars, A. Prince, H. Okamoto; “Handbook of Ternary Alloy Phase Diagrams”; ASM International; 1995.

[13] B. Vandevelde; “Influence of PCB properties on solder joint fatigue life of assembled IC packages”; European Microelectronics and Packaging Symposion; 2004.

[14] H. Albrecht; “Interface reactions in microelectronic solder joints and associated intermetallic compounds: an investigation of their mechanical properties using nanoindention”; Electronics Packaging Technology Conference; 2003.

[15] G. Jang; “The nanoidentation characteristics of Cu₆Sn₅, Cu₃Sn and Ni₃Sn₄ intermetallic compounds in the solder bump.

[16] IPC-A-610D; “Acceptability of Electronic Assemblies”; IPC Association Connecting Electronics Industries; 2005.

[17] B. Willis; “Lead-free Defect Guide”; SMART Group.

[18] G. Diepstraten; “Lead-Free and its Effects on Soldering Process Parameters”; Vitronic Soltec.

[19] J. Hwang; “Implementing lead-free electronics – a manufacturing guide”; McGraw-Hill; 2004.

[20] ELFNET Roadmap; European Electronics Interconnection - www.europeanleadfree.net