METHOD AND APPARATUS FOR ELECTROCHEMICAL ETCHING, AND ELECTROCHEMICALLY-ETCHED PRODUCT

摘要

An electrochemical etching device (10) comprises an etching bath (12) holding an n-type silicon substrate with one side in contact with electrolyte, an electrode (28) arranged in electrolyte (14) including hydrogen fluoride acid, a power supply (30) having its positive electrode connected to the silicon substrate and its negative electrode connected to the electrode, and a light source (56) for illuminating the side of the silicon substrate opposite to that being etched. The electrolyte comprises hydrogen fluoride and has a water content in a molar ratio of 0.9. The conductivity of the electrolyte is greater than 29 mS/cm.