Method and a system for characterising structures etched in a substrate
AssigneeUnity Semiconductor Corporation
InventorWolfgang Alexander Iff
Life of this patent
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Abstract
A method for characterising high aspect ratio (“HAR”) structures etched in a substrate includes, for at least one structure, an interferometric measurement step, carried out with a low-coherence interferometer positioned on a top surface of the substrate, for measuring with a measurement beam, at least one depth data relating to a depth of the HAR structure, and a first adjusting step for adjusting a diameter, at the top surface, of the measurement beam according to at least one top critical dimension (“top-CD”) data relating to a width of the HAR structure.
Claims15
A method for characterising structures etched in a substrate, comprising, for at least one structure:
- an interferometric measurement step, carried out with a low-coherence interferometer positioned on a top surface of said substrate, for measuring with a measurement beam positioned on the at least one structure, at least one depth data relating to a depth of said at least one structure;
- and
- a first adjusting step for adjusting a diameter, at said top surface, of the measurement beam according to at least one top critical dimension (“top-CD”) data relating to a width of said at least one structure;
- wherein the diameter of said measurement beam is adjusted to be between 0.3 and 5 times the smallest transverse dimension of the at least one structure.
A system for characterising high aspect ratio (“HAR”) structures etched in a substrate, comprising:
- a low-coherence interferometer, arranged on a top surface of said substrate, for measuring with a measurement beam positioned on the structure at least one depth data relating to a depth of said HAR structure;
- and
- an adjustment unit for adjusting a diameter, at said top surface, of the measurement beam according to at least one top critical dimension (“top-CD”) data relating to a width of said HAR structure;
- wherein the diameter of said measurement beam is adjusted to be between 0.3 and 5 times the smallest transverse dimension of the at least one structure.
Dependencies are inferred from the claim text.