Film thickness metrology

摘要

Methods for determining a target thickness of a conformal film with reduced uncertainty, and an integrated circuit (IC) chip having a conformal film of the target thickness are provided. In an embodiment, a first critical dimension of a structure disposed on a wafer is measured. Said structure has at least one vertical surface. A first conformal film is deposited over the structure covering each of a horizontal and the vertical surface of the structure. A second critical dimension of the covered structure is then measured. The target thickness of the conformal film is determined based on difference between the first CD measured on the structure and the second CD measured on the covered structure.

主权项

1. A method of controlling a thickness of a conformal film, the method comprising:
measuring a first critical dimension (CD) of a structure disposed on a wafer, the structure having at least one vertical surface and at least one horizontal surface; after measuring the first CD, depositing a first conformal film over the structure to form a coated structure, wherein the first conformal film covers each of the horizontal surface and the vertical surface of the structure; after depositing the first conformal film, measuring a second CD of the coated structure; determining a target first conformal film thickness based on a difference between the first CD and the second CD; and after determining the target first conformal film thickness, determining whether any adjustment in the first conformal film thickness is needed by determining whether the target first conformal film thickness deviates from a desired target first conformal film thickness, and if needed adjusting the first conformal film thickness by one of further depositing of the first conformal film in the case where the target first conformal film thickness is less than the desired target first conformal film thickness, or removing at least a partial thickness of the first conformal film in the case where the target first conformal film thickness is greater than the desired target first conformal film thickness, until the first conformal film thickness is equal to a desired first conformal film thickness.