Copper CMP flatness monitor using grazing incidence interferometry
AssigneeKLA-Tencor Techologies Corporation
InventorsDieter Mueller, George Kren, Cedric Affentauschegg
Life of this patent
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Abstract
A system and method for in-line inspection of specimens such as semiconductor wafers is provided. The system provides scanning of sections of specimens having predetermined standardized characteristics using a diffraction grating that widens and passes nth order (n>0) wave fronts to the specimen surface and a reflective surface for the transmitted light beam. Light energy is transmitted in a narrow swath across the portion of the surface having the standardized features. The wavefronts are combined using a second diffraction grating and passed to a camera system having a desired aspect ratio.
Claims41
A system for performing a scan of a portion of a specimen surface, comprising:
- a collimator for collimating light energy received from a low coherence light energy generating device;
- a first diffraction grating combining light energy transmitted from said collimator and passing nonzero order light energy toward said specimen;
- a reflective surface for receiving predetermined order light energy from said diffraction grating;
- a second diffraction grating for receiving light reflected from said specimen and from said reflective surface;
- and
- a collimator for receiving light energy from said second diffraction grating;
- wherein said first diffraction grating passes light energy only over a portion of the specimen surface having predetermined standardized characteristics, said portion comprising less than half of the specimen surface, and said predetermined standardized characteristics comprising a set of physical attributes varying between specific sections on the specimen surface.
A method for inspecting a portion of a surface of a specimen, comprising:
- transmitting light energy toward said specimen;
- diffracting said light energy into predetermined order light energy;
- directing said diffracted light energy toward a predetermined portion of said specimen surface having predetermined standardized characteristics and simultaneously toward a reflective surface mounted substantially parallel to said specimen surface, wherein said predetermined portion comprises less than half of the specimen surface;
- receiving predetermined order light energy reflected from said specimen and said reflective surface and combining the received light energy;
- and
- directing said light energy to a light receiving device;
- wherein said predetermined standardized characteristics comprise known physical variations between sections on the specimen surface.
A method for inspecting a surface of a specimen, said surface having a surface area, comprising:
- disposing a swath of nonzero order light energy having approximate predetermined dimension across said surface of said specimen while simultaneously transmitting predetermined order light energy toward a reflective surface, said swath covering less than approximately half of the surface area of the specimen;
- and
- combining light energy received from said surface and said reflective surface;
- wherein said disposing comprises disposing light energy to a portion of said surface having predetermined standardized characteristics, and said predetermined standardized characteristics comprising at least one from a group comprising surface pitch variations, wire density variations, linewidth variations, and line space variations.
Dependencies are inferred from the claim text.