These are challenging times for computer chip engineers. A technology the industry has been counting on to etch the tiny features of the next few generations of chips is still not ready.
Known as extreme ultraviolet lithography, or EUV, the technology is years behind schedule. Although the approach works, UV light sources powerful enough to etch chips quickly enough for mass production are lacking. In 2012, Intel invested $4 billion in the Dutch company ASML, a supplier of manufacturing equipment, to bolster work on perfecting the technique (see “The Moore’s Law Moon Shot”). Leading chip makers Samsung and TSMC have since each added $375 million of their own to ASML’s research effort, but there is still no indication as to when EUV might be ready.
A radical alternative to conventional lithography now looks increasingly viable. Known as directed self-assembly, it involves using solutions of compounds known as block copolymers that assemble themselves into regular structures. Block copolymers are made up of different units (the blocks) that prefer to be separate, like oil and water; left alone, these compounds typically produce swirling, fingerprint-like patterns. But if guided by a “pre-pattern” of chemical guides made with conventional lithography, the block copolymers produce lines and other regular patterns. Crucially, those final patterns can have much smaller details than those of the pre-pattern. A final pattern made in this way can then be used as a template for the chemical processes that etch features into a silicon wafer—the same process that is the end point of conventional lithography.