SummaryCompaniesDUV production effort being led by little-known Shanghai company AishengnaAishengna incorporated teams from top Chinese lithography startupsWestern curbs could make local tools a fallback if foreign servicing tightensSINGAPORE, July 28 (Reuters) - China has begun mass producing domestically developed immersion deep-ultraviolet (DUV) lithography machines, a technology crucial to advanced chipmaking, a person familiar with ​the matter said, marking a key step forward in Beijing's d...