Abstract: The present disclosure generally relates to semiconductor processing in which an alignment mark is formed. An example is method of semiconductor processing. First and second recesses are formed in a semiconductor substrate. A conformal dielectric layer is formed in the first and second recesses and over the semiconductor substrate. A fill material is formed over the conformal dielectric layer in the first recess and over the conformal dielectric layer in the second recess. The fill material fills at least the first recess over the conformal dielectric layer. The fill material in the first and second recesses is recessed to below a top surface of the conformal dielectric layer. The recessed fill material in the first and second recesses is etched. Exposed portions of the conformal dielectric layer are etched. The second recess including the conformal dielectric layer and the recessed fill material disposed therein forms an alignment mark.