Inspection system with multiple illumination sources
AssigneeKLA-Tencor Technologies Corporation
InventorSteven R. Lange
Life of this patent
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Abstract
The present invention pertains to techniques for increasing the available illumination light, increasing the resolution, and optimizing the spectrum of optical inspection systems. These techniques involve combining the light beams from two or more separate illumination sources. In one embodiment, this performed by utilizing two separate illumination sources wherein one of the illumination sources compensates the other illumination source in the wavelength range where illumination light intensity is low. Specifically, this can be performed by utilizing a broadband illumination source and a narrowband illumination source combined with dichroic beamsplitters.
Claims22
An optical inspection system for semiconductor inspection comprising:
- a first illumination source that directs a first light beam into the optical inspection system in order to illuminate a semiconductor specimen;
- and
- a second illumination source that directs a second light beam into the optical inspection system in order to further illuminate the semiconductor specimen,
- the first and second light sources producing light within the wavelength range of 100-700 nanometers,
- the first and the second light beams being coincident with each other at a dichroic beamsplitter such that the first and second light beams have approximately the same LaGrange Invariants at the dichroic beamsplitter, whereby the first and second light beams are used together for inspection purposes.
An optical inspection system for semiconductor inspection comprising:
- a broadband illumination source that directs a broadband light beam into the optical inspection system in order to illuminate a semiconductor specimen;
- and
- a narrow band illumination source that directs a narrowband light beam into the optical inspection system in order to further illuminate the semiconductor specimen, wherein the broadband and the narrowband light beams are coincident with each other at a dichroic beamsplitter such that the broadband and the narrowband light beams have approximately the same LaGrange Invariants at the dichroic beamsplitter, whereby the broadband and the narrowband light beams are used together for inspection purposes.
An optical inspection system for semiconductor inspection comprising:
- a broadband illumination source that directs a broadband light beam into the optical inspection system in order to illuminate a semiconductor specimen;
- a first narrow band illumination source that directs a first narrowband light beam into the optical inspection system in order to farther illuminate the semiconductor specimen, wherein the broadband and the first narrowband light beams are coincident with each other at a first dichroic beamsplitter such that the broadband and the first narrowband light bears have approximately the name LaGrange Invariant, at the first dichroic beamsplitter;
- and
- a second narrowband illumination source that directs a second narrowband light beam into the optical inspection system in order to further illuminate the semiconductor specimen, whereby the broadband, the first and second narrowband light beams are used together for inspection purposes.
An optical inspection system for semiconductor inspection comprising:
- a broadband illumination source that directs a broadband light beam into the optical inspection system in order to illuminate a semiconductor specimen;
- and
- a narrow band illumination source that directs a narrowband light beam into the optical inspection system in order to further illuminate the semiconductor specimen, wherein the broadband light beam spans a first range of wavelengths, and wherein the narrowband light beam spans a second range of wavelengths, the second range of wavelengths being positioned within the shorter wavelength end of the first range thereby lowering the effective inspection wavelength of the inspection system, wherein the broadband and the narrow band illumination sources are coincident with each other at a dichroic beamsplitter such that the broadband and the narrow band illumination soirees have approximately the same LaGrange Invariants at the dichroic beamsplitter, whereby the broadband and the narrowband light beams are used together for inspection purposes.
Dependencies are inferred from the claim text.