A device includes a substrate feature disposed over a substrate. The substrate feature has a first length extending along a first direction and a second length extending along a second direction. The first length is greater than the second length. The device also includes a first material feature disposed over the substrate. The first material feature has a first surface in physical contact with the substrate feature and a second surface opposite to the first surface. The first surface has a third length extending along the first direction and a fourth length extending along the second direction. The third length is greater than the fourth length. The second surface has a fifth length extending along the first direction and a sixth length extending along the second direction. The sixth length is greater than the fifth length.