Methods for Improving Interlayer Dielectric Layer Topography

A method comprising:

• forming a first contact etch stop layer over a first gate structure having a first height, wherein the first contact etch stop layer has a first thickness;
• forming a second contact etch stop layer over a second gate structure having a second height that is less than the first height, wherein the second contact etch stop layer has a second thickness that is greater than the first thickness;
• and
• forming an interlayer dielectric (ILD) layer over the first contact etch stop layer and the second contact etch stop layer.

A method comprising:

• depositing a first dielectric layer having a first thickness over a first gate structure in a first region and a second gate structure in a second region;
• forming a first mask layer that covers the first dielectric layer in the first region and exposes the first dielectric layer in the second region;
• removing the exposed first dielectric layer in the second region;
• removing the first mask layer;
• depositing a second dielectric layer having a second thickness over the first dielectric layer in the first region and the second gate structure in the second region, wherein the second thickness is greater than the first thickness;
• forming a second mask layer that covers the second dielectric layer in the second region and exposes the second dielectric layer in the first region, wherein the second mask layer covers a portion of the second dielectric layer disposed over a boundary between the first region and the second region;
• removing the exposed second dielectric layer in the second region;
• removing the second mask layer;
• and
• forming a third dielectric layer over the first dielectric layer in the first region and the second dielectric layer in the second region.