A structure and method for fabricating a spacer structure for semiconductor devices, such as a multi-gate structure, is provided. The dummy gate structure is formed by depositing a dielectric layer, forming a mask over the dielectric layer, and patterning the dielectric layer. The mask is formed to have a tapered edge. In an embodiment, the tapered edge is formed in a post-patterning process, such as a baking process. In another embodiment, a relatively thick mask layer is utilized such that during patterning a tapered results. The profile of the tapered mask is transferred to the dielectric layer, thereby providing a tapered edge on the dielectric layer.