Semiconductor chips are among the smallest and most detailed objects humans can manufacture. Shrinking the scale and upping the complexity is a fight against the limits of physics, and optical lithography—etching nanometre-scale patterns onto silicon with short-wavelength light—is its most extreme frontier. ASML, a Dutch firm that builds such lithography tools, takes an almost sci-fi approach by blasting molten tin droplets with lasers in a vacuum to produce extreme ultraviolet (EUV) light with a wavelength of just 13.5nm. Now, some researchers hope to generate more powerful EUV beams with a particle accelerator that propels electrons to nearly the speed of light.