Slanted Gratings for AR White Paper May 2020

Large area slanted etching for Augmented Reality


Reactive Ion Beam Etching RIBE is a technique well suited to etching slanted features. The technique allows localised removal of material using a broad ion beam. The material is removed at the wafer surface following collisions between accelerated ions and reactive species formed in the ion source. Control and repeatability in defining slanted features is contingent on advanced Ion beam source configuration and experienced selection of processing conditions. In this paper, we describe how Oxford Instruments Plasma Technology solution delivers controlled processing of slanted gratings used as light coupler for Augmented Reality waveguide combiners. We demonstrate control of the slant angle, the groove depth and the filling ratio for large wafer sizes.

Augmented Reality is an exciting technology with application in medical care, education and navigation.


Substrate holder


Cl 2 , CF 4 , CHF 3

Schematic of a Ion beam processing chamber. The wafer is positioned on a substrate holder which is angled to face the ion source. The angle of the substrate holder can be adjusted to enable angled etching.

Gas ring for CAIBE

Schematic of processing chamber.

2 Large area slanted etching for Augmented Reality © Oxford Instruments plc, 2020.

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