Used extensively in semiconductor manufacturing and microfabrication processes, buffered oxide etchant (BOE) selectively removes silicon dioxide (SiO₂) layers without significantly attacking the underlying silicon substrate. Its primary application is in photolithography, where it etches exposed oxide regions to create precise patterns for integrated circuits. The buffering action, typically from ammonium fluoride, stabilizes the etch rate and improves uniformity, making it ideal for critical dimension control. BOE is also employed in cleaning and preparing wafers by removing native oxide layers before deposition or diffusion steps. Due to its controllable and isotropic etching behavior, it is favored in MEMS (Micro-Electro-Mechanical Systems) fabrication for releasing delicate structures. Safety precautions are necessary during use, as it releases hazardous fumes and requires handling in corrosion-resistant equipment.