PURPOSE: To enable a direct management by forming a monitoring pattern and monitoring a lift-off.

CONSTITUTION: A pattern for monitoring an etching amount is formed on the end of a chip separated from an element forming portion or a scribing line, and the monitoring pattern is formed simultaneously with the element parts of the pattern having a width of double of necessary etching amount (w). Since the pattern is formed by the same process as the element, the time when the pattern is lifted OFF designates that it arrives at the amount (w) in which the side etching amount of an Si3N4 film in the element is necessary. If the patterns having slight changes in the widths are provided before and after 2w, the advancing amount of the side etching can be monitored by monitoring which monitor is lifted OFF.