Even though Restricted Use of Hazardous Substances (RoHS) directive is in full effect now, some small amounts of lead are inside almost every computer chip, as the material is used to package the actual piece of silicon to substrate. But, Intel Corp. has announced that its future microprocessors made using 45nm process technology will not use any lead at all.

Starting from the July 1, 2006, EU restricted the use of six substances within electrical and electronic equipment (EEE), thereby contributing to the protection of human health and the environment. The list of hazardous substances includes such materials as Lead (Pb), Mercury (Hg), Cadmium (Cd), Hexavalent Chromium, Polybrominated biphenyls as well as Polybrominated diphenyl ethers. While when the computers are used, they are not dangerous, when the components are utilized after users get rid of old machines, those elements become harmful.

The vast majority of substances that included lead have historically been found on various devices based on print-circuit boards, e.g., mainboards, graphics cards, etc. However, chip designers have to care about the absence of lead from packaging of their products too. For instance, lead can be found in heat-spreaders, substrate, solder balls and even bumping. For all these situations developers have to find a substitute, for instance, solder balls can consist of tin (Sn), silver (Ag) and copper (Cu) composite, which has been found as the most suitable.

Lead is used in a variety of micro-electronic “packages” and the “bumps” that attach a chip to the packages. Packages wrap around the chip and ultimately connect it to the motherboard. Different types of packages are used for processors targeted at specific market segments, including mobile, desktop and server. Package designs include pin grid array, ball grid array or land grid array, and all are 100% lead-free in case of chips made using Intel’s 45nm high-k technology. In 2008, the company will also transition its 65nm chipset products to 100% lead-free technology.

Both Advanced Micro Devices and Intel have already eliminated use of lead from substrate and solder balls, nonetheless, bumping, or the first-level interconnect – the solder joint that connects the silicon die to the package substrate – in processor packages still used alloys containing lead. Intel’s announcement means that the company will also begin to employ a tin/silver/copper alloy to attach silicon dice to substrates.

According to Intel, because of the complex interconnect structure of the company’s advanced silicon technologies, “a great deal of engineering work” was required to remove the remaining lead in Intel’s processor packages and integrate a new solder alloy system.

“Intel is taking an aggressive stance toward environmental sustainability, from the elimination of lead and a focus on greater energy efficiency of our products to fewer air emissions and more water and materials recycling,” said Nasser Grayeli, Intel vice president and director of assembly test technology development, technology and manufacturing group.