A patent filed by Huawei and Chinese partners points to efforts to manufacture 5nm-class chips without the use of EUV lithography, according a Bloomberg report. The patent application describes self-aligned quadruple patterning (SAQP) technology, typically used to overcome lithographic limits. The technique was popular in the 2010s, before the introduction of EUV lithography. Ironically, Intel stumbled when trying to apply SAQP in volume production of 10nm chips (link in Dutch).
Self-aligned patterning processes turn a number of structures into multiple, more tightly spaced pieces of offspring. In case of SAQP, for example, one line turns into four lines by a combination of etching and deposition steps. Sophisticated atomic layer deposition is key to successful self-aligned patterning.