Method of making semiconductor device with air-bridge interconnection

A method of producing a semiconductor device having an air-bridge interconnection comprising the steps of:

• (a) forming a semiconductor material;
• (b) forming a metal layer on a portion of said semiconductor material having a narrow portion in the intermediate portion thereof and end portions of larger width than said narrow portion adjacent said narrow portion;
• and
• (c) forming said air-bridge interconnection by first etching said semiconductor material using said metal layer as a mask to cut said semiconductor material around said metal layer with side-etching controlled to form a bottom having a predetermined depth from said metal layer;
• forming a resistive layer on said bottom;
• and etching said semiconductor material for a second time, a width of said narrow portion and widths of said end portions being determined such that cuts under said narrow portion on both sides of said narrow portion developed by said etching join together by said side-etching to remove a mass of said semiconductor material under said metal layer while leaving masses of said semiconductor material under said end portions, said resistive layer reducing an etching speed in the depth direction in said second etching.