Particle beam current monitoring technique
First Claim
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1. A method of determining a current of an ion beam directed at a target during an ion implantation process, the method comprising acts of:
- generating an ion beam;
separating the ion beam by energy analysis to select different charge states of a same species of ions to provide a sub-beam of ions having a desired charge state, which constitutes an implantation ion beam, and a sub-beam of ions having an undesired charge state;
directing the implantation ion beam onto the target to effect the ion implantation process;
intercepting the sub-beam of ions having the undesired charge state to provide an intercepted sub-beam;
measuring a current of the intercepted sub-beam to provide a measured current;
determining an absolute value of a current of the implantation ion beam based on the measured current and on a known relationship between the current of the intercepted sub-beam and the current of the implantation ion beam.
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Abstract
A method of monitoring particle beam current in an ion implanter in which the ion beam is analyzed to separate it into a separate sub-beam for each ion charge state. At least one sub-beam, having a charge state different from the desired charge state, is intercepted, and the current of the intercepted sub-beam is measured. This current is useful as an estimate of the current of the desired sub-beam which is used for the implantation.
28 Citations
16 Claims
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1. A method of determining a current of an ion beam directed at a target during an ion implantation process, the method comprising acts of:
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generating an ion beam;
separating the ion beam by energy analysis to select different charge states of a same species of ions to provide a sub-beam of ions having a desired charge state, which constitutes an implantation ion beam, and a sub-beam of ions having an undesired charge state;
directing the implantation ion beam onto the target to effect the ion implantation process;
intercepting the sub-beam of ions having the undesired charge state to provide an intercepted sub-beam;
measuring a current of the intercepted sub-beam to provide a measured current;
determining an absolute value of a current of the implantation ion beam based on the measured current and on a known relationship between the current of the intercepted sub-beam and the current of the implantation ion beam. - View Dependent Claims (2, 3, 4, 5, 7, 13, 14, 15)
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6. An apparatus that determines a current of an ion beam directed at a target during an ion implantation process, comprising:
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an ion beam generator that provides a beam of ions;
a separating device that separates the beam of ions by energy analysis to select different charge states of a same species of ions to provide a sub-beam of ions having a desired charge state, which constitutes an implantation ion beam, and a sub-beam of ions having an undesired charge state;
a measuring device that measures a current of the sub-beam of ions having the undesired charge state, to provide a measured current; and
a device, coupled to the measuring device, that determines an absolute value of a current of the implantation ion beam based on the measured current and on a known relationship between the current of the implantation ion beam and the measured current. - View Dependent Claims (8, 9, 10, 11, 12, 16)
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Specification