Method for making silica strain test structures

A method for forming silica stain on a substrate to facilitate monitoring of the silica stain during integrated circuit manufacture. The method includes providing a silica stain test structure which has a silicon substrate, a hydrophilic silicon dioxide containing layer disposed above the silicon substrate, and a plurality of cavities formed in the silicon substrate through the silicon dioxide containing layer. The cavities have hydrophobic sidewalls. The method also includes exposing the silica stain test structure to deionized water, and drying the silica stain test structure to form the silica stain on the silicon dioxide containing layer.