| 摘要 |
PURPOSE:To enable to perform etching with high yield and favorable reproducibility by a method wherein width of the opening of a monitor mask pattern and the incident angle of a beam are selected as to enable to detect the etching end point in time. CONSTITUTION:An SiO2 film 2 is provided on a silicon wafer 1, an Si3N4 film 3 is provided thereon, a resist film 4 is provided thereon, and an opening 5 for the monitor pattern of etching is formed in a region different from an orginal etching region for formation of an element. Then, a light source 6 to project an incident beam 6a forming an incident angle theta is provided at the obliquely upper side in the right-angled direction to the width W of the opening 5, a reflected light detector 7 is provided at the symmetrical position interposing the opening between the light source, and etching is proceeded radiating the beam 6a toward the opening 5 from the light source 6. When etching depth reaches T, and the width W and the incident angle theta are selected as to effect relation W=2T/tantheta, and moreover when etching is proceeded more than the desired depth T, a reflected light 7a becomes to not enter the reflected light detector 7, and the fact that the desired etching depth is attained can be understood at the point in time thereof. |
