Method to detect surface metal contamination
AssigneeAOTI Operating Company, Inc.
InventorVictor Higgs
Life of this patent
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Abstract
A method for detecting surface or near surface metal contamination in a semiconductor or silicon structure is described in which the structure or a part thereof is exposed to an excitation beam of predetermined wavelength and collecting luminescence from the structure in as the form of PL map having a substantially uniform PL intensity level provided by the semiconductor; and inspecting the map for one or more regions of enhanced PL intensity identifying characteristic surface or near surface metal contamination. In particular, the method is applied as an in-process quality control or as a quality control of processed structures such as interconnects.
Claims20
A method for detecting surface or near surface metal contamination in a semiconductor or silicon structure, comprising exposing the structure or a part thereof to an excitation beam of predetermined wavelength and collecting luminescence from the structure in the form of a PL map characterised by a substantially uniform PL intensity level provided by the semiconductor;
- and inspecting the map for one or more regions of enhanced PL intensity, identifying characteristic surface or near surface metal contamination.
The method of any preceding claim applied as a method for detecting surface or near surface metal contamination or contamination trail in a wafer comprising semiconductor or silicon and metal functional components comprising interconnects and the like.
The method of any preceding claim wherein a sensitive rapid room temperature photoluminescence mapping system is employed which produces maps or visual images of a structure as distinct from a spectrum or other indirect representation.
The method of any preceding claim wherein excitation is by a high intensity laser beam.
The method of any preceding claim comprising the use of a pulsed laser excitation source and the measurement of luminescence images as a function of time.
The method of any preceding claim in which confocal optics are used to obtain depth discrimination of the contaminants by exciting a large volume of said semi conductor with a laser and collecting images from a series of focal planes.
A method for the preparation of a metal interconnect and/or a method for the detection of metal contamination directly or by cross-contamination following the preparation of a metal interconnect, comprising etching at least one track or via in a silicon wafer and laying down a barrier lining and depositing a diffusable metal and sealing with a further barrier layer and polishing to produce a finished product, and exposing to an excitation beam of predetermined wavelength, and collecting luminescence from the structure in the form of a PL map and inspecting for one or more regions of enhanced PL intensity identifying potential front side or back side diffusable metal contamination;
- and verifying by additional tests.
The method of any preceding claim comprised as an in-process quality control or as a quality control of processed structures.
A semiconductor or silicon structure tested for surface metal contamination according to the method of the invention and verified for use, being contaminant free.
The use of an apparatus in photoluminescence imaging of a semiconductor or silicon structure for the detection of surface region metal contamination.
Dependencies are inferred from the claim text.