US Patent 11257719 Methods for improving interlayer dielectric layer topography

Integrated circuit devices having improved interlayer dielectric (ILD) layer topography and methods of fabrication thereof are disclosed herein. An exemplary integrated circuit device includes a first gate structure having a first height disposed over a substrate in a first region and a second gate structure having a second height disposed over the substrate in a second region. The second height is less than the first height. A first contact etch stop layer is disposed over the first gate structure. A second contact etch stop layer disposed over the second gate structure. The first contact etch stop layer has a first thickness, the second contact etch stop layer has a second thickness, and the second thickness is greater than the first thickness. An interlayer dielectric layer is disposed over the first contact etch stop layer and the second contact etch stop layer. A difference between a first sum of the first height and the first thickness and a second sum of the second height and the second thickness is less than or equal to about 10%.