Photo-acoustic device and method for non-contact measurement of thin layers
AssigneeNovelis Inc.
InventorsHeinrich Prinzhorn, Stefan Erdmann, Thomas Wuttke, Andreas Bauer, Bernd Abel, Ales Charvat
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Abstract
A measuring device for non-mechanical-contact measurement of a layer, the measuring device including a light source operative to generate a pulse adapted to interact with the layer so as to generate a thermal wave in a gas medium present adjacent the layer. The thermal wave causes an acoustic signal to be generated. The measuring device further includes a detector adapted to detect a first signal responsive to the acoustic signal, the detector not being in mechanical contact with the layer. The first signal is representative of the measured layer.
Claims18
A measuring device for non-mechanical-contact measurement of a layer, the measuring device comprising:
- a light source operative to generate a pulse adapted to interact with the layer so as to generate a thermal wave in a gas medium present adjacent the layer, said thermal wave causing an acoustic signal to be generated;
- and
- a detector adapted to detect a first signal responsive to the acoustic signal, said detector not being in mechanical contact with the layer, wherein said first signal is representative of the measured layer;
- wherein the pulse is associated with an absorption of the pulse within the layer, the absorption being substantially greater than an absorption of the pulse within a substrate in mechanical contact with the layer, wherein the layer is disposed between the substrate and the gas medium.
A method for non-mechanical-contact measurement of a layer, the method comprising:
- generating a pulse adapted to interact with the layer to generate a thermal wave in a gas medium present adjacent the layer, thereby causing an acoustic signal to be generated;
- and
- detecting a first signal responsive to the acoustic signal without mechanically contacting the layer, wherein said first signal is representative of the measured layer;
- wherein the pulse is associated with an absorption of the pulse within the layer, the absorption being substantially greater than an absorption of the pulse within a substrate in mechanical contact with the layer, wherein the layer is disposed between the substrate and the gas medium.
Dependencies are inferred from the claim text.