Remote resistivity measurement
AssigneeSela Semiconductor Engineering
InventorDan Hashimshony
Life of this patent
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Abstract
Apparatus and method for measuring surface resistivity of a wafer (12). A source of high frequency radiation (6, 41) emits an incident wave burst that impinges the wafer at a desired spot location. A reflected wave burst is detected at an appropriate time window by a receiver (8, 42). The relationship between incident and reflected energies is a function of the surface resistivity of the wafer.
Claims9
Apparatus for non-contact measurement of resistivity of a surface layer of a wafer, said surface layer having a depth, the apparatus comprising:
- a source of high frequency radiation, for irradiating said wafer;
- a detector of high frequency radiation, positioned to detect radiation from said source reflected from said wafer;
- and
- a high speed switching device operable to switch on said detector following a first predetermined delay to switch off said detector after a second predetermined delay.
A method for non-contact measurement of resistivity of a surface layer of a wafer, said surface layer having a depth, comprising the steps of:
- employing a source of high frequency radiation for irradiating said wafer;
- employing a detector for detecting radiation from a selected point on said wafer;
- and
- employing a high speed switching device to switch said detector on and off, thereby to enable detection of the resistivity of said surface layer.
Dependencies are inferred from the claim text.