Brewer Science and ASE Group receive SEMI Award

Two companies, Brewer Science and Advanced Semiconductor Engineering, have received the 2014 SEMI Award for North America. The awards honour Terry Brewer of Brewer Science for revolutionising optical lithography with anti-reflective coatings; and Jason Chang and Tien Wu of ASE for relentlessly pursuing the commercialisation of copper wire bonds when gold was the industry standard.

Some innovations become such an integral part of the semiconductor manufacturing industry’s infrastructure that the technology itself becomes fundamental - such as the use of anti-reflective coatings in optical lithography and copper for wire bonding.

Currently, multilayer systems are commonly used in optical lithography, with some processes using 5-6 layers, as well as double- or triple-patterning steps, to achieve the necessary resolution. However, in the early 1980s, 1 µm was considered the limit for optical lithography and single-layer photoresist suffered from reflections that caused significant variations in critical dimensions.

Dr Terry Brewer invented an anti-reflective coating that was effective in eliminating reflective interference and provided good adhesion to multiple materials and resist. At the time, the introduction of an anti-reflective coating was a radically different approach - adding layers to the single-layer exposure films of lithography. Brewer Science, founded in 1981, developed and commercialised anti-reflective coating materials that were instrumental in the industry’s progress from g-line to 248 nm to 193 nm lithography, and now to extreme ultraviolet (EUV) and directed self-assembly (DSA) technology.

Due to the expense of gold for wire bonding, the semiconductor industry began exploring alternatives in the 1980s. Yet manufacturers did not adopt copper wire bonds due to concerns about yield, reliability, throughput and customer acceptance. In 2006, Jason Chang and Tien Wu of ASE committed to underwrite risk, resolve technical problems and address customer concerns. Requiring an investment reaching hundreds of millions of dollars with no assurance of success, in 2007 they started working with materials and equipment vendors to establish a supply chain and also with foundries to establish metallurgy for bonding pads compatible with copper wire bonds. In 2009, Chang and Wu had dramatic results with a few selected customers. By 2013, more than half of ASE production was in copper wire bonds and today it exceeds 70%. ASE moved copper wire bonds into volume production and the industry benefits. Today, long-term reliability of copper wire bonds exceeds that of gold.

“Terry Brewer’s ‘out of the box’ thinking changed the face of optical lithography, and Jason Chang and Tien Wu persevered against all odds to commercialise copper wire bonds,” said Karen Savala, president, SEMI Americas.

“These two SEMI awards represent change in both materials and processes on opposite ends of the production of integrated circuits,” said Bill Bottoms, chairman of the SEMI Award Advisory Committee. “From defining the initial patterns on silicon wafers to connecting the completed integrated circuits to the rest of the world, these innovations solved difficult challenges for the semiconductor industry - maintaining the pace of progress in both cost and product performance.”