Optical emission spectroscopic techniques for monitoring etching
First Claim
1. A method of etching, the method comprising:
- striking a plasma discharge;
flowing a gas mixture comprising a hydrogen-containing gas and helium through the plasma discharge to form plasma effluents;
flowing the plasma effluents through a plurality of apertures to a silicon layer on a substrate, the silicon layer having a first thickness;
etching the silicon layer with the plasma effluents;
measuring the intensity of emission from hydrogen from a reaction of plasma effluents with the silicon layer;
measuring the intensity of emission from helium in the plasma effluents;
integrating the intensity of the emission from helium over the duration the plasma effluents are being flowed to the silicon layer to obtain an integrated intensity of helium;
integrating the intensity of the emission from hydrogen over the duration the plasma effluents are being flowed to the silicon layer to obtain an integrated intensity of hydrogen;
calculating a parameter from the integrated intensity of hydrogen and the integrated intensity of helium;
comparing the parameter to a reference value corresponding to a target thickness of silicon etched;
extinguishing the plasma discharge when the integrated intensity is equal to or greater than the reference value to define a partially etched silicon layer on the substrate having a second thickness less than the first thickness.
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Accused Products
Abstract
Embodiments may include a method of etching. The method may also include flowing a gas mixture through a plasma discharge to form plasma effluents. The method may further include flowing the plasma effluents through a plurality of apertures to a layer on a substrate. The layer may have a first thickness. In addition, the method may include etching the layer with the plasma effluents. The method may also include measuring the intensity of emission from a reaction of plasma effluents with the layer. The method may further include summing the intensity of the emission while the plasma effluents are being flowed to the layer to obtain an integrated intensity. The method may then include comparing the integrated intensity to a reference value corresponding to a target etch thickness. The method may include extinguishing the plasma discharge when the integrated intensity is equal to or greater than the reference value.
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Citations
18 Claims
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1. A method of etching, the method comprising:
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striking a plasma discharge; flowing a gas mixture comprising a hydrogen-containing gas and helium through the plasma discharge to form plasma effluents; flowing the plasma effluents through a plurality of apertures to a silicon layer on a substrate, the silicon layer having a first thickness; etching the silicon layer with the plasma effluents; measuring the intensity of emission from hydrogen from a reaction of plasma effluents with the silicon layer; measuring the intensity of emission from helium in the plasma effluents; integrating the intensity of the emission from helium over the duration the plasma effluents are being flowed to the silicon layer to obtain an integrated intensity of helium; integrating the intensity of the emission from hydrogen over the duration the plasma effluents are being flowed to the silicon layer to obtain an integrated intensity of hydrogen; calculating a parameter from the integrated intensity of hydrogen and the integrated intensity of helium; comparing the parameter to a reference value corresponding to a target thickness of silicon etched; extinguishing the plasma discharge when the integrated intensity is equal to or greater than the reference value to define a partially etched silicon layer on the substrate having a second thickness less than the first thickness. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of measuring an amount of a silicon layer etched with a plasma source, the method comprising:
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measuring the intensity of emission from hydrogen from a reaction of plasma effluents with the silicon layer; measuring the intensity of emission from helium in the plasma effluents; integrating the intensity of the emission from helium over the duration that the plasma effluents are being flowed to the silicon layer to obtain an integrated intensity of helium; integrating the intensity of the emission from hydrogen over the duration the plasma effluents are being flowed to the silicon layer to obtain an integrated intensity of hydrogen; calculating a parameter from the integrated intensity of hydrogen and the integrated intensity of helium; and measuring the amount of the silicon layer etched by comparing the parameter to a calibration curve. - View Dependent Claims (14, 15, 16, 17, 18)
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Specification