Ion implanter and ion implantation method
View Patent ↗An ion implanter includes a high energy multi-stage linear acceleration unit including a plurality of linear acceleration units, wherein each of the linear acceleration units includes high frequency accelerators respectively in a plurality of stages; and a control device controlling an operation of the high energy multi-stage linear acceleration unit in accordance with a data set defining a voltage amplitude, a frequency, and a phase of the high frequency accelerator in each of the plurality of stages.
1 . An ion implanter comprising:
a high energy multi-stage linear acceleration unit including a plurality of linear acceleration units, wherein each of the linear acceleration units includes high frequency accelerators respectively in a plurality of stages; and
a control device controlling an operation of the high energy multi-stage linear acceleration unit in accordance with a data set defining a voltage amplitude, a frequency, and a phase of the high frequency accelerator in each of the plurality of stages,
wherein the control device is configured to
acquire a first data set for setting beam energy of an ion beam output from the high energy multi-stage linear acceleration unit to be a first output value,
determine a second data set for setting the beam energy of the ion beam output from the high energy multi-stage linear acceleration unit to be a second output value different from the first output value, based on the first data set, and
operate the high energy multi-stage linear acceleration unit in accordance with the determined second data set, and
the control device determines the second data set so that an acceleration phase of the high frequency accelerator in each of the plurality of stages in at least one linear acceleration unit of the plurality of linear acceleration units is the same between the first data set and the second data set, in all of the high frequency accelerators respectively in the plurality of stages, and so that the voltage amplitude of the high frequency accelerator in at least one of the plurality of stages is different between the first data set and the second data set.
2 . The ion implanter according to claim 1 ,
wherein the voltage amplitude of the high frequency accelerator in at least one stage other than an most upstream stage and a most downstream stages is different between the first data set and the second data set.
3 . The ion implanter according to claim 1 ,
wherein each of the voltage amplitudes of the high frequency accelerators in two or more of the plurality of stages is different between the first data set and the second data set.
4 . The ion implanter according to claim 3 ,
wherein each of the voltage amplitudes of the high frequency accelerators in at least half of the plurality of stages is different between the first data set and the second data set.
5 . The ion implanter according to claim 3 ,
wherein in the high frequency accelerators in the two or more of the plurality of stages in each of which the voltage amplitude of the high frequency accelerator is different between the first data set and the second data set, a change amount between the first data set and the second data set of the voltage amplitude of the high frequency accelerator in each of the two or more of the plurality of stages is the same.
6 . The ion implanter according to claim 3 ,
wherein in the high frequency accelerators in the two or more of the plurality of stages in each of which the voltage amplitude of the high frequency accelerator is different between the first data set and the second data set, a change rate between the first data set and the second data set of the voltage amplitude of the high frequency accelerator in each of the two or more of the plurality of stages is the same.
7 . The ion implanter according to claim 1 , wherein the control device is further configured to:
determine the high frequency accelerator in at least one of the plurality of stages into which a difference between the first data set and the second data set in the voltage amplitude of the high frequency accelerator is to be introduced, based on a difference between the first output value and the second output value.
8 . The ion implanter according to claim 1 , wherein the control device is further configured to:
determine the high frequency accelerator in at least one of the plurality of stages into which a difference between the first data set and the second data set in the voltage amplitude of the high frequency accelerator is to be introduced, based on a difference between a maximum value of the voltage amplitude settable in the high frequency accelerator in each of the plurality of stages, and the voltage amplitude of the high frequency accelerator in each of the plurality of stages which is defined in the first data set.
9 . The ion implanter according to claim 1 , wherein the control device is further configured to:
determine the high frequency accelerator in at least one of the plurality of stages into which a difference between the first data set and second data set in the voltage amplitude of the high frequency accelerator is to be introduced, based on a minimum change amount of the voltage amplitude settable in the high frequency accelerator in each of the plurality of stages.
10 . The ion implanter according to claim 1 ,
wherein the first data set is determined by adjusting the acceleration phase of the high frequency accelerator in at least one of the plurality of stages, based on a measurement value of at least one beam characteristic of the ion beam output from the high energy multi-stage linear acceleration unit, and
the second data set is determined by adjusting the voltage amplitude of the high frequency accelerator in at least one of the plurality of stages, based on a transport simulation of the ion beam by the high energy multi-stage linear acceleration unit.
11 . The ion implanter according to claim 1 ,
wherein the ion implantation is performed with skipping measurement of at least one beam characteristic of the ion beam output from the high energy multi-stage linear acceleration unit operating in accordance with the second data set.
12 . The ion implanter according to claim 1 , wherein the control device is further configured to:
measure at least one beam characteristic of the ion beam output from the high energy multi-stage linear acceleration unit operating in accordance with the second data set; and
adjust the voltage amplitude of the high frequency accelerator in at least one of the plurality of stages which is defined in the second data set, based on a measurement value of the at least one beam characteristic.
13 . The ion implanter according to claim 1 , wherein the control device is further configured to:
calculate a first timing at which an ion particle transported by the high energy multi-stage linear acceleration unit operating in accordance with the first data set passes through the high frequency accelerator in each of the plurality of stages, and first passing energy of the ion particle when the ion particle passes through the high frequency accelerator in each of the plurality of stages;
calculate the acceleration phase of the high frequency accelerator in each of the plurality of stages, based on the calculated first timing and the calculated first passing energy;
calculate a second timing at which the ion particle passes through the high frequency accelerator in each of the plurality of stages when the voltage amplitude of the high frequency accelerator in at least one of the plurality of stages is changed while the calculated acceleration phase of the high frequency accelerator in each of the plurality of stages is fixed, and second passing energy of the ion particle when the ion particle passes through the high frequency accelerator in each of the plurality of stages; and
determine the phase of the high frequency accelerator in each of the plurality of stages which is defined in the second data set, based on the phase of the high frequency accelerator in each of the plurality of stages which is defined in the first data set, and a phase difference between the first timing and the second timing at which the ion particle passes through the high frequency accelerator in each of the plurality of stages.
14 . The ion implanter according to claim 1 ,
wherein each of the linear acceleration units includes electrostatic quadrupole lens devices respectively in a plurality of stages, the electrostatic quadrupole lens device in each of the plurality of stages is disposed on a downstream side of the corresponding high frequency accelerator in each of the plurality of stages, and the data set further defines an applied voltage of the electrostatic quadrupole lens device in each of the plurality of stages, and
the control device is further configured to:
calculate first incident energy of an ion particle transported by the high energy multi-stage linear acceleration unit operating in accordance with the first data set when the ion particle is incident into the electrostatic quadrupole lens device in each of the plurality of stages;
calculate second incident energy of the ion particle transported by the high energy multi-stage linear acceleration unit operating in accordance with the second data set when the ion particle is incident into the electrostatic quadrupole lens device in each of the plurality of stages; and
determine the applied voltage of the electrostatic quadrupole lens device in each of the plurality of stages which is defined in the second data set, based on the applied voltage of the electrostatic quadrupole lens device in each of the plurality of stages which is defined in the first data set, and the first incident energy and the second incident energy of the ion particle when the ion particle is incident into the electrostatic quadrupole lens device in each of the plurality of stages.
15 . The ion implanter according to claim 14 ,
wherein the applied voltage of the electrostatic quadrupole lens device in each of the plurality of stages which is defined in the second data set is a value obtained by multiplying the applied voltage of the electrostatic quadrupole lens device in each of the plurality of stages which is defined in the first data set by a ratio between the first incident energy and the second incident energy of the ion particle when the ion particle is incident into the electrostatic quadrupole lens device in each of the plurality of stages.
16 . The ion implanter according to claim 1 ,
wherein the ion implanter further includes an electric field application device disposed on a downstream side of the high energy multi-stage linear acceleration unit, and applying an electric field to the ion beam output from the high energy multi-stage linear acceleration unit, and the data set further defines an applied voltage of the electric field application device, and
the control device is further configured to:
determine the applied voltage of the electric field application device which is defined in the second data set, based on the applied voltage of the electric field application device which is defined in the first data set, and the first output value and the second output value of the beam energy of the ion beam output from the high energy multi-stage linear acceleration unit.
17 . The ion implanter according to claim 16 ,
wherein the applied voltage of the electric field application device which is defined in the second data set is a value obtained by multiplying the applied voltage of the electric field application device which is defined in the first data set by a ratio between the first output value and the second output value.
18 . The ion implanter according to claim 1 ,
wherein the ion implanter further includes a magnetic field application device disposed on a downstream side of the high energy multi-stage linear acceleration unit, and applying a magnetic field to the ion beam output from the high energy multi-stage linear acceleration unit, and the data set further defines an applied magnetic field of the magnetic field application device, and
the control device is further configured to:
determine the applied magnetic field of the magnetic field application device which is defined in the second data set, based on the applied magnetic field of the magnetic field application device which is defined in the first data set, and the first output value and the second output value of the beam energy of the ion beam output from the high energy multi-stage linear acceleration unit.
19 . The ion implanter according to claim 18 ,
wherein the applied magnetic field of the magnetic field application device which is defined in the second data set is a value obtained by multiplying the applied magnetic field of the magnetic field application device which is defined in the first data set by a square root of a ratio between the first output value and the second output value.
20 . The ion implanter according to claim 1 , wherein the control device is further configured to:
determine a plurality of the second data sets for setting the beam energy of the ion beam output from the high energy multi-stage linear acceleration unit to be a plurality of the second output values different from the first output value, based on the first data set,
wherein the acceleration phase of the high frequency accelerator in each of the plurality of stages is the same between the first data set and each of the plurality of second data sets, in all of the high frequency accelerators respectively in the plurality of stages,
the voltage amplitude of the high frequency accelerator in at least one of the plurality of stages is different between the first data set and each of the plurality of second data sets, and
the plurality of second data sets are switched therebetween to perform the ion implantations by sequentially irradiating the workpiece with a plurality of the ion beams output from the high energy multi-stage linear acceleration unit operating in accordance with the plurality of second data sets.
21 . The ion implanter according to claim 20 ,
wherein measurement of at least one beam characteristic is skipped for each of the plurality of ion beams.