Used primarily in semiconductor manufacturing and microfabrication processes, buffered oxide etchant (BOE) selectively removes silicon dioxide (SiO₂) layers without significantly attacking the underlying silicon substrate. It is commonly applied in photolithography steps to etch oxide films, create device isolation structures, and define capacitor or transistor components. The buffering action, typically from ammonium fluoride, stabilizes the etch rate and improves uniformity, making it ideal for precision patterning. BOE is also used in MEMS (Micro-Electro-Mechanical Systems) fabrication and glass etching due to its controllable and anisotropic etching characteristics. Safety precautions are necessary as it contains hydrofluoric acid, which is highly corrosive and toxic.