Method and apparatus for determining surface characteristics by using SPM techniques with acoustic excitation and real-time digitizing
AssigneeAdvanced Micro Devices, Inc.
InventorsDmytro Chumakov, Holm Geisler, Ehrenfried Zschech
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Abstract
By digitizing the UFM signal without using a lock-in amplifier, substantially all of the information initially contained in the UFM output signal may be maintained and may then be used for further data processing. Consequently, any type of model or evaluation algorithm may be used without being restricted to a very narrow bandwidth, as is the case in lock-in based techniques. The digitizing is performed on a real-time basis, wherein a complete UFM curve is digitized and stored for each scan position. In this way, quantitative meaningful values for specific surface-related characteristics with a nanometer resolution may be obtained.
Claims20
A metrology system, comprising:
- a scanning probe microscope;
- a modulation unit connected to the scanning probe microscope to enable a modulated excitation of a sample;
- a signal processing unit connected to said scanning probe microscope to receive an output signal of said scanning probe for a plurality of scan positions defining a two-dimensional region said signal processing unit being configured to digitize and record a frequency spectrum including a plurality of frequency components of a frequency band for each scan position;
- and
- a data processor operable to generate an image of the sample over the two-dimensional region based on the plurality of frequency components of the frequency band.
A method, comprising:
- scanning a sample surface by a scanning probe at least a plurality of scan positions defining a two-dimensional region to obtain a surface-related output signal at each of said plurality of scan positions;
- exciting said sample surface with a modulated signal;
- digitizing said output signal including a frequency spectrum including a plurality of frequency components of a frequency band for each of said plurality of scan positions;
- and
- generating an image of the sample over the two-dimensional region based on the plurality of frequency components of the frequency band.
Dependencies are inferred from the claim text.