Method of etching a semiconductor substrate

A method of etching a semiconductor substrate, the method comprising the steps of:

• providing the semiconductor substrate;
• providing an etch mask over the semiconductor substrate to expose a portion of the semiconductor substrate;
• and
• simultaneously wet etching trenches of different depths into the semiconductor substrate at a temperature below ambient,
• wherein the step of wet etching through the semiconductor substrate includes using a mixture of hydrofluoric acid, nitric acid, phosphoric acid, sulfuric acid, and a wetting agent to etch the semiconductor substrate.

A method of fabricating a semiconductor component, the method comprising the steps of:

• providing a semiconductor substrate having a first surface opposite a second surface;
• thinning the semiconductor substrate;
• providing a support layer for the second surface of the semiconductor substrate;
• disposing a patterned mask layer over the first surface of the semiconductor substrate, wherein the patterned mask layer has a first opening exposing a first portion of the first surface and a second opening exposing a second portion of the first surface, the first opening wider than the second opening;
• and
• etching the first and second portions of the first surface of the semiconductor substrate with a mixture comprised of hydrofluoric acid, nitric acid, phosphoric acid, sulfuric acid, and a wetting agent to form a first trench having a first depth located under the first opening of the patterned mask layer and a second trench having a second depth located under the second opening of the patterned mask layer, the first depth greater than the second depth, the temperature of the mixture below 18 degree Celsius.