Used extensively in semiconductor manufacturing and microfabrication processes, buffered oxide etchant (BOE) selectively removes silicon dioxide (SiO₂) layers without attacking underlying silicon or photoresist materials. Its primary application is in patterning and etching oxide films during integrated circuit production. The buffering action, typically from ammonium fluoride, stabilizes the etch rate and improves uniformity, making it ideal for critical dimension control. It is also employed in MEMS (Micro-Electro-Mechanical Systems) fabrication to release movable structures by etching away sacrificial oxide layers. Due to its controllable and isotropic etching behavior, BOE is favored in processes requiring high precision and reproducibility, such as gate oxide definition and contact hole opening. Additionally, it is used in cleaning and preparing silicon wafers prior to deposition or oxidation steps.