Chip houses go green with lack of lead

In a move aimed at accelerating the use of 'lead-free' technologies, Infineon Technologies, Philips Semiconductors and STMicroelectronics - Europe's three largest semiconductor manufacturers - are proposing a standard that not only provides a common definition of 'lead-free' but also assesses alternative materials to lead that can be used in the semiconductor industry.

Lead, along with tin, is a critical component of the solder traditionally used for printed circuit board assembly. It is also widely used in semiconductor packaging, for example, as a coating on the leads of packages, in power IC packages as the die attach and for the balls of Ball Grid Array (BGA) packages.

One of the major barriers against eliminating the use of lead in the industry has been a lack of internationally agreed standards and methodologies for evaluating the quality and reliability of 'lead-free' technologies. In contrast, single lead-tin alloy has been used for many decades and standard procedures are used worldwide to evaluate its quality and long-term reliability.

'Many different kinds of 'lead-free' solder alloys and soldering processes are being investigated or developed around the world, using multiple combinations of elements like tin, silver, copper, bismuth, indium and zinc, all of which require increased temperature profiles relative to the well known tin-lead alloys during the soldering process,' said Carlo Cognetti, Vice President for New Package Development at STMicroelectronics. 'To accelerate the transition to 'lead-free' technology, the electronics industry needs a common approach to quantifying solderability, heat resistance and other issues that affect reliability.'

'At present, there is not even an internationally agreed definition of the maximum amount of lead that can be allowed in a 'lead-free' component or process,' said Dr. Wolfgang Bloch, Head of Environment Protection and Safety Management at Infineon Technologies. 'The market is confused because there are no rules or standards so far for evaluating alternative technologies. What we are doing is proposing some key ground rules that will help accelerate progress. Our initiative shows the inevitable transition to 'green' assembly on a global scale.'

'Europe has taken the lead in proposing the world's first legislation to eliminate lead from electronic equipment and components,' said Leo Klerks, Environmental Officer at Philips Semiconductors. 'Our three companies' interest in using lead-free soldering technologies has partly been fuelled by legislative restrictions from the European Commission.

Effective from 1 January 2006, materials such as lead, mercury, cadmium and others will be forbidden in electrical and electronic devices. By sharing our knowledge and enthusiasm, Europe's leading semiconductor manufacturers can make huge steps towards meeting this goal.'

The three companies will introduce their 'lead-free' products far in advance of the legislative deadlines. Fully qualified 'lead-free' components will be available by the end of this year.

The proposal of Infineon, Philips and STMicroelectronics contains an upper limit for 'lead-free' components of 0.1 percent related to the individual material, not to the whole package or component.