METHOD FOR FORMING CONTACT HOLE IN SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for forming a contact hole is to prevent an undoped oxide film, which is exposed when etching a doped oxide film, from being etched. CONSTITUTION: After a field oxide film(101) is formed on a silicon substrate(100), an insulating oxide film(1) is deposited on the field oxide film, and a bit line or capacitor(3) is formed on the insulating oxide film. After an undoped oxide film(2) of a thin thickness is deposited on the bit line or capacitor, a doped oxide film of a thick thickness is deposited on the undoped oxide film. A photoresist mask pattern(5) is formed on the doped oxide film, and the doped oxide film is isotropic-etched using an HF vapor of a low pressure. The residue doped oxide film and the undoped oxide film are etched to form a contact hole(10) exposing the substrate and the bit line or capacitor. When the doped oxide film is etched, a partial pressure is controlled to be below 500 Pascal.