Semiconductor dynamic quantity-sensor and method of manufacturing the same

A semiconductor physical quantity sensor manufacturing method using a SOI substrate composed of a silicon substrate as a first layer, an insulating layer as a second sacrifice layer formed on said first layer, and a silicon or polysilicon layer as a third layer formed on said second layer, wherein said third layer is machined to form a sensing element for sensing physical quantities and removing said second layer to form a semiconductor physical quantity sensor, said method comprising the steps of:

• coating said third layer with protective film;
• forming a sensing element by using said protective film as a mask;
• removing said second sacrifice layer by wet etching;
• substituting an etching liquid used in said wet etching with a displacement liquid;
• drying said sensing element by removing said displacement liquid sticking on said sensing element in a state wherein an acceleration in an opposite direction to a direction toward said first layer is applied to said sensing element;
• and
• removing said protective film by dry etching.