Film thickness metrology

A method comprising:

• depositing a first conformal film over a wafer having a structure thereon, thereby forming a coated structure, the structure including at least one vertical surface and at least one horizontal surface;
• measuring a first critical dimension (CD) of the structure;
• performing an etch to remove a partial thickness of the first conformal film from each of the at least one vertical surface and at least one horizontal surface;
• measuring a second CD of the coated structure;
• and
• determining a target first conformal film thickness based on a difference between the first CD and the second CD.

An integrated circuit (IC) chip comprising:

• a wafer;
• at least one structure having at least one vertical surface and at least one horizontal surface, the at least one structure being disposed on the wafer;
• and
• a first conformal film over the wafer including the at least one structure, wherein the first conformal film has a first thickness, and wherein the first thickness is represented by the following equation:
• t=|½[CD1−CD2]|
• where
• t=the first target thickness;
• CD1=a first critical dimension (CD);
• and
• CD2=a second CD.