A method of fabricating an integrated circuit includes applying photoresist to a MESA dielectric layer of a semiconductor structure, to generate a photoresist layer. The method also includes exposing the photoresist layer with a grayscale mask, to generate an exposed photoresist layer. The photoresist exposed layer includes a thick photoresist pattern in a first region, a thin photoresist pattern in a second region where a height of the thin photoresist pattern is less than half a height of the thick photoresist pattern, and a gap region between the thick photoresist pattern and the thin photoresist pattern.