A high-aspect-ratio-microstructure (HARM) is provided. The structure includes: a substrate; a lower structure with a comb shape fixedly mounted on said substrate and having first plural comb fingers, wherein each of the first plural comb fingers has a thin slot thereon; an upper structure with a comb shape having second plural comb fingers, wherein the lower structure and the upper structure have a height difference therebetween so as to form an uneven surface; and a lateral strengthening structure formed at vertically peripheral walls of the first plural comb fingers and the second plural comb fingers for protecting the plural first and second comb fingers.