Structural Evolution of the Global Lithography Equipment Trade Network: Implications for Smart-City Supply-Chain Resilience

Smart cities increasingly depend on chip-centered digital infrastructure, whose resilience is closely linked to the stability of upstream semiconductor manufacturing equipment supply. Disruptions in lithography equipment trade may propagate downstream through the semiconductor supply chain and affect the security and continuity of urban digital systems. Existing studies on semiconductor trade networks have paid insufficient attention to the timing of long-term structural shifts and the mechanisms through which external shocks reshape network organization. Using UN Comtrade data on lithography-equipment-related semiconductor manufacturing equipment from 2010 to 2024, this study develops an integrated topological-spatial analytical framework based on complex network analysis. The framework combines change-point detection, community evolution analysis, node roles and critical channel identification. The results show that the global lithography equipment trade network is increasingly characterized by the concentration of key nodes and critical channels, community differentiation in trade relations, and dependence on cross-community linkages. These findings provide both a complementary perspective and a methodological reference for understanding upstream structural risks in chip-centered urban digital systems.