PROBLEM TO BE SOLVED: To provide a micro-bump production method by which a bump in a nano-size class having a periodic structure can easily be machined, and to provide a fine-mesh production method, a laser machining device, and a substrate for production.
SOLUTION: A laser is oscillated, and the emitted laser beam is separated into a plurality of luminous fluxes. The separated luminous fluxes are condensed on a thin film 1c on a substrate 1b in a state of being interfered. The interference region of a fluence higher than a bump formation threshold and lower than a bump critical threshold is formed by the interference. The thin film 1c in the interference region is deformed to produce a bump 1a having a periodic structure.