National Semiconductor supplies Nokia with analog components used in handheld wireless devices and network equipment. Compliance with the European Union’s forthcoming RoHS directive is a topical focus in cooperation between National and Nokia. Martin Schnepf, EFS and packaging expert from the Quality Assurance Department of National’s European headquarters, says National had already previously eliminated five of the six substances whose use is restricted by the directive, leaving only lead to work upon. The work started back in 2000 and by the end of 2004 lead-free versions were available for over 90 percent of products. Some high-power packages still use lead as a high melting temperature die attaches material. This use is exempted by the RoHS directive.
National has chosen the strategy of continuing to offer its customers leaded and lead-free versions of its products to enable the customers to transition smoothly from the standard production process to the lead-free environment. “We don’t want to put the customer under pressure and say, you have to accept lead-free components as of tomorrow as only those will then be available,” Schnepf says. The lead-free solders have an undesirable environmental side effect: they require a higher reflow temperature than lead-containing solders. Some products will have difficulty withstanding the thermal strain at the strictest moisture sensitivity level. Click here to read more…
