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US 12,169,359 B2Granted
Manufacture of surface relief structures
AssigneeSnap Inc.
InventorsIan Sturland, Mark Venables, Tracey Hawke, Rory Mills, Ian Macken
Life of this patent
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Abstract
A method and apparatus for the etching of variable depth features in a substrate is described. Movement of the substrate relative to an etchant (e.g. into or out of the etchant) during the etching process is utilised to provide a varying etch time, and hence depth, across the substrate, and in various examples this is enabled without requiring a varying mask.
Claims18
A method of etching a blazed surface relief structure in a substrate, the method comprising:
- moving the substrate between a first position and a second position in an etching system, wherein in the first position only a first part of the area to be etched is exposed to an etchant, wherein the etchant is an anisotropic etchant, and in the second position the area to be etched is exposed to the etchant such that the first part of the area to be etched is exposed to the etchant for a longer period of time than at least one other part of the area to be etched, and wherein the movement is defined according to an etching profile, both the movement of the substrate and an orientation of the substrate are relative to a surface of the etchant defined according to the etching profile;
- and
- removing the substrate from the etchant when etching is complete;
- wherein the surface relief structure comprises a variable depth etching profile.
1 more element
A method of etching a nanostructure-based surface relief structure in a substrate, the method comprising:
- moving the substrate between a first position and a second position in an etching system, wherein in the first position only a first part of the area to be etched is exposed to an anisotropic etch process, and in the second position at least one other part of the area to be etched is exposed to the anisotropic etch process such that the first part of the area to be etched is etched for a longer period of time than the at least one other part of the area to be etched, and wherein the movement is defined according to an etching profile, both the movement of the substrate and an orientation of the substrate are relative to a surface of the etchant defined according to the etching profile;
- and
- in response to the anisotropic etch process being complete, removing the substrate from the anisotropic etch process;
- wherein the surface relief structure comprises a variable depth etching profile;
- wherein moving the substrate between the first position and the second position in the etching system comprises either moving the substrate from the first position to the second position or moving the substrate from the second position to the first position.
2 more elements
Dependencies are inferred from the claim text.