Wet Etch Process

• Wet etch is a process that uses chemical solution to dissolve the materials on the wafer surface to achieve the device and circuit requirements.

• The byproducts of the wet etch chemical reaction are gases, liquids, or solids that are soluble in the etchant solution.

• The three basic steps of wet etching are: etch, rinse and dry.

• Wet etch has good selectivity and high etch rate.

• Wet etch equipment is much cheaper than the dry etch equipment.

• For feature sizes less than 3mm, wet etch is not useful because of its isotropic etch profile and has been gradually replaced by plasma etch.

• Wet etch is used to strip blanket film on the wafer surface because of its high selectivity. [3]