Semiconductor device manufacturing method and semiconductor device manufacturing apparatus

A semiconductor device manufacturing method comprising the steps of:

• a first step for forming a polycrystalline silicon layer on a semiconductor substrate;
• a second step for forming an electrically-conductive layer containing at least one of a metal and an electrically-conductive metal compound on the polycrystalline silicon layer;
• a third step for forming a mask layer comprising plural patterns extending in a predetermined direction on the electrically-conductive layer;
• a fourth step for patterning the electrically-conductive layer using the mask layer;
• a fifth step for etching the polycrystalline silicon layer by plasma etching using a first etching gas and using the mask layer such that the polycrystalline silicon layer remains with a predetermined thickness;
• and
• a sixth step for etching away the polycrystalline silicon layer with the predetermined thickness by plasma etching using a second etching gas different from the first etching gas and using the mask layer,
• wherein, during said fifth step, a main surface of said semiconductor substrate is irradiated with inspection light and an end-point of said plasma etching using said first etching gas is determined on the basis of intensity of a polarized light component perpendicular to the predetermined direction contained in reflected light of said inspection light which is reflected from said main surface of said semiconductor substrate.