Atomic layer deposition on optical structures

A method for processing an optical workpiece, comprising:

• applying a mask on a first layer disposed on a substrate, wherein the first layer comprises grating structures separated by trenches formed in the first layer, wherein the grating structures comprise a first group of the grating structures having a desired critical dimension and a second group of the grating structures having an initial critical dimension, wherein the desired critical dimension is greater than the initial critical dimension, and wherein the mask covers the first group of the grating structures and leaves exposed the second group of the grating structures;
• positioning the substrate containing the mask disposed on the first layer within a processing chamber;
• depositing a second layer on the mask and the second group of the grating structures by atomic layer deposition to produce corrected grating structures separated by the trenches, wherein the corrected grating structures have a corrected critical dimension greater than the initial critical dimension;
• and
• removing the second layer deposited on the mask and removing the mask from the first layer, wherein the first group of the grating structures and the corrected grating structures are exposed.

A method for processing an optical workpiece, comprising:

• positioning a substrate containing a first layer having a first refractive index within a processing chamber, wherein the first layer comprises grating structures separated by trenches formed in the first layer, wherein the grating structures comprise a first group of the grating structures having a desired critical dimension and a second group of the grating structures having an initial critical dimension, wherein the desired critical dimension is greater than the initial critical dimension, and wherein the first layer comprises amorphous silicon, silicon nitride, silicon oxide, silicon oxynitride, silicon oxycarbide, titanium oxide, niobium oxide, dopants thereof, or any combination thereof;
• applying a mask on the first layer, wherein the mask covers the first group of the grating structures and leaves exposed the second group of the grating structures;
• depositing a second layer having a second refractive index by atomic layer deposition, wherein the second layer is deposited on the mask and to completely fill the trenches of the second group and cover the grating structures of the second group, wherein the second layer comprises amorphous silicon, silicon nitride, silicon oxide, silicon oxynitride, titanium oxide, niobium oxide, aluminum oxide, dopants thereof, or any combination thereof, and wherein a difference between the first refractive index and the second refractive index is about +/−0.001 to about +1-0.1;
• and
• removing the second layer deposited on the mask and removing the mask from the first layer, wherein the first group of the grating structures is exposed and the second group of the grating structures contains the second layer deposited thereon.