Measurement of the mobile ion concentration in the oxide layer of a semiconductor wafer
First Claim
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1. A method for determining the mobile ion concentration within an oxide layer disposed on a surface of a semiconductor wafer, comprising:
- a) depositing charge on at least a portion of the surface of the oxide layer at a low temperature at which said mobile ions do not substantially move,b) measuring the contact potential on the surface of the oxide layer at said low temperature,c) heating the semiconductor wafer and oxide layer to a temperature sufficient to activate the drift of said mobile ions,d) measuring the shift in contact potential after said heating, ande) determining the mobile ion concentration within the oxide layer on the basis of the shift.
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Abstract
A method and apparatus for measuring the concentration of mobile ions in the oxide layer of a semiconductor wafer from the contact potential shift caused by ion drift across the oxide that includes depositing charge (e.g., using a corona discharge device) on the surface of the oxide and heating the wafer to allow mobile ions in the oxide (especially Na+) to drift. The difference in the contact potential measured before and after heating provides an indication of the mobile ion concentration in the oxide layer.
132 Citations
24 Claims
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1. A method for determining the mobile ion concentration within an oxide layer disposed on a surface of a semiconductor wafer, comprising:
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a) depositing charge on at least a portion of the surface of the oxide layer at a low temperature at which said mobile ions do not substantially move, b) measuring the contact potential on the surface of the oxide layer at said low temperature, c) heating the semiconductor wafer and oxide layer to a temperature sufficient to activate the drift of said mobile ions, d) measuring the shift in contact potential after said heating, and e) determining the mobile ion concentration within the oxide layer on the basis of the shift. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 24)
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15. A system for the measurement of mobile contaminant ion concentration in an oxide layer of a semiconductor wafer, comprising:
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a charge deposition device configured to deposit charge on the oxide layer of the wafer; a temperature stress device including a element for heating the wafer to a temperature sufficient to allow mobile ions to drift; and a measurement device configured to measure the contact potential on the surface of the oxide layer prior to and after heating of the water by said element of said temperature stress device. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23)
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Specification