Method and apparatus for fabricating structures using chemically selective endpoint detection

An integrated circuit created using a selective etching process, the selective etching process comprising:

• receiving a silicon substrate with a first layer composed of a first material and a second layer composed of a second material, wherein the second layer is deposited over the first layer;
• performing a first etching operation that etches the second layer;
• wherein the first etching operation etches through some but not all of the second layer, so that a portion of the second layer remains covering the first layer;
• and
• wherein an etch rate of the first etching operation through the second material is substantially equal to an etch rate of the first etching operation through the first material;
• and
• performing a second etching operation to selectively etch through the remaining portion of the second layer using a selective etchant;
• wherein an etch rate of the selective etchant through the second material is faster than an etch rate of the selective etchant through the first material, so that the second etching operation etches through the remaining portion of the second layer and stops at the first layer.