Method and system for interferometric height measurement
AssigneeInternational Business Machines Corporation
InventorsGernot Brasen, Christian Laue, Matthias Loeffler, Heiko Theuer
Life of this patent
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Abstract
A system and method for interferometric height measurement. A first coherent light beam and a second coherent light beam is generated. At least the first coherent light beam is reflected from a first region into a first return beam and the second coherent light beam is reflected from a second region into a second return beam. At least a first reflectivity of the first region is measured. A topography-dependent phase shift of the first return beam and the second return beam is determined with reference to a curve relating the first reflectivity to a material-dependent phase shift. A height based on the topography-dependent phase shift is measured.
Claims7
An interferometric method for measuring said method comprising:
- generating a first coherent light beam and a second coherent light beam;
- reflecting at least said first coherent light beam from a first region into a first return beam and reflecting said second coherent light beam from a second region into a second return beam;
- measuring at least a first reflectivity of said first region;
- determining a topography-dependent phase shift of said first return beam and said second return beam based on said first reflectivity, wherein said determining step further comprises determining the topography-dependent phase shift with reference to a curve relating said first reflectivity to a material-dependent phase shift;
- and
- measuring a height based on said topography-dependent phase shift.
Dependencies are inferred from the claim text.