Method for manufacturing infrared detecting device

A method for manufacturing an infrared detecting device, comprising:

• preparing an SOI substrate provided with a silicon layer over a support substrate through an oxide layer interposed therebetween;
• forming a isolation layer which surrounds an infrared detection portion forming area formed in the SOI substrate and extends from the silicon layer to a predetermined depth of the support substrate through the oxide layer;
• forming a protective film over the surface of the silicon layer corresponding to the infrared detection portion forming area;
• forming through holes which penetrate the silicon layer, the oxide layer and the protective film;
• and
• etching the support substrate corresponding to the infrared detection portion forming area surrounded by the isolation layer to a predetermined depth of the support substrate using the through holes,
• wherein the isolation layer has a circular form or a form of a regular polygonal more than a regular pentagon in shape.