Real time measurement of etch rate during a chemical etching process
First Claim
1. A method for contactless, real-time, in-situ monitoring of a chemical etching process during etching of at least one wafer in a wet chemical etchant bath, said method comprising the steps of:
- a) providing two conductive electrodes in the wet chemical bath, wherein said two electrodes are proximate to but not in contact with the at least one wafer and further wherein each of the electrodes is positioned on an opposite side of the at least one wafer;
b) monitoring an electrical characteristic between the two electrodes as a function of time in the etchant bath of the at least one wafer, wherein a prescribed change in the electrical characteristic is indicative of a prescribed condition of the etching process; and
c) recording a plurality of values of said electrical characteristic as a function of time during etching.
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Accused Products
Abstract
A contactless method and apparatus for real-time in-situ monitoring of a chemical etching process during etching of at least one wafer in a wet chemical etchant bath are disclosed. The method comprises the steps of providing two conductive electrodes in the wet chemical bath, wherein the two electrodes are proximate to but not in contact with a wafer; monitoring an electrical characteristic between the two electrodes as a function of time in the etchant bath of the at least one wafer, wherein a prescribed change in the electrical characteristic is indicative of a prescribed condition of the etching process; and recording a plurality of values of the electrical characteristic as a function of time during etching. From the plurality of recorded values and corresponding times, instantaneous etch rates, average etch rates, and etching end points may be determined. Such a method and the apparatus therefor are particularly useful in a wet chemical etch station.
36 Citations
11 Claims
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1. A method for contactless, real-time, in-situ monitoring of a chemical etching process during etching of at least one wafer in a wet chemical etchant bath, said method comprising the steps of:
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a) providing two conductive electrodes in the wet chemical bath, wherein said two electrodes are proximate to but not in contact with the at least one wafer and further wherein each of the electrodes is positioned on an opposite side of the at least one wafer; b) monitoring an electrical characteristic between the two electrodes as a function of time in the etchant bath of the at least one wafer, wherein a prescribed change in the electrical characteristic is indicative of a prescribed condition of the etching process; and c) recording a plurality of values of said electrical characteristic as a function of time during etching. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for contactless, real-time, in-situ monitoring of a chemical etching process during etching of at least one wafer in a wet chemical etchant bath, said method comprising the steps of:
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a) providing two conductive electrodes in the wet chemical bath, wherein said two electrodes are proximate to but not in contact with the at least one wafer; b) monitoring an impedance between the two electrodes as a function of time in the etchant bath of the at least one wafer, wherein a prescribed change in the impedance is indicative of a prescribed condition of the etching process; and c) recording a plurality of values of said electrical characteristic as a function of time during etching.
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11. A method for contactless, real-time, in-situ monitoring of a chemical etching process during etching of at least one wafer in a wet chemical etchant bath, said method comprising the steps of:
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a) providing two conductive electrodes in the wet chemical bath, wherein said two electrodes are proximate to but not in contact with the at least one wafer and further wherein each of the electrodes is positioned on an opposite side of the at least one wafer; b) monitoring an impedance between the two electrodes as a function of time in the etchant bath of the at least one wafer, wherein a prescribed change in the impedance is indicative of a prescribed condition of the etching process; and c) recording a plurality of values of said electrical characteristic as a function of time during etching.
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Specification