Gratings with variable etch heights for waveguide displays

A manufacturing system comprising:

• a deposition system configured to perform a deposition of an etch-compatible film over a substrate, the etch-compatible film comprising a first surface and a second surface opposite to the first surface and configured to deposit a photoresist over the first surface after a surface profile is created on the first surface;
• an etching system configured to perform a partial removal of the etch-compatible film to create the surface profile on the first surface with a plurality of etch heights relative to the substrate;
• and
• a patterning system configured to perform a lithographic patterning of the photoresist deposited over the created profile in the etch-compatible film, to perform a selective removal of the etch-compatible film using the lithographically patterned photoresist to obtain the plurality of different etch heights relative to the substrate and one or more duty cycles corresponding to the etch-compatible film deposited over the substrate, and to selectively remove the lithographically patterned photoresist to form an optical grating including a portion of the etch-compatible film with the plurality of different etch heights relative to the substrate and the one or more duty cycles corresponding to the etch-compatible film.

An optical grating formed by a process comprising steps of:

• performing a deposition of an etch-compatible film over a substrate, the etch-compatible film comprising a first surface and a second surface opposite to the first surface;
• performing a partial removal of the etch-compatible film to create a surface profile on the first surface with a plurality of different etch heights relative to the substrate;
• performing a deposition of a photoresist over the first surface having the surface profile;
• performing a lithographic patterning of the photoresist deposited over the first surface;
• performing a selective removal of the etch-compatible film using the lithographically patterned photoresist to obtain the plurality of different etch heights relative to the substrate and one or more duty cycles corresponding to the etch-compatible film deposited over the substrate;
• and
• selectively removing the lithographically patterned photoresist to form the optical grating including a portion of the etch-compatible film with the plurality of different etch heights relative to the substrate and the one or more duty cycles corresponding to the etch-compatible film.