Patent Number: 
Section: claims

1. An ion implanting apparatus which performs an ion implantation by irradiating an ion beam having passed through a separation slit to a substrate, the ion implanting apparatus comprising:(a) an ion source that generates plasma containing a desired type of ion to be implanted into the substrate;(b) an extraction electrode system that extracts an ion beam having a rectangular section and containing the desired type of ion from the plasma generated from the ion source;(c) a mass-separation electromagnet that performs a mass-separation by bending the extracted ion beam in a thickness direction so as to derive the ion beam containing the desired type of ion; and(d) the separation slit that receives the ion beam having passed through the mass-separation electromagnet and that allows the desired type of ion to selectively pass therethrough, wherein the separation slit is operable to vary a shape of a gap through which the ion beam passes, wherein the separation slit includes a first slit and a second slit that are disposed on both sides in a thickness direction of the ion beam so as to be opposed to each other with an interval therebetween, wherein the first slit and the second slit respectively include a plurality of small slits that are separated in a width direction of the ion beam, wherein the small slits are arranged so that a gap through which the ion beam passes is not formed between the small slits that are adjacent to each other in a width direction, and wherein the small slits are operable to move independently in a thickness direction. 2. An ion implanting apparatus which performs an ion implantation by irradiating an ion beam having passed through a separation slit to a substrate, the ion implanting apparatus comprising:(a) an ion source that generates plasma containing a desired type of ion to be implanted into the substrate;(b) an extraction electrode system that extracts an ion beam having a rectangular section and containing the desired type of ion from the plasma generated from the ion source;(c) a mass-separation electromagnet that performs a mass-separation by bending the extracted ion beam in a thickness direction so as to derive the ion beam containing the desired type of ion;(d) the separation slit that receives the ion beam having passed through the mass-separation electromagnet and that allows the desired type of ion to selectively pass therethrough; and(e) a variable slit that is disposed between the extraction electrode system and the mass-separation electromagnet so as to form a gap through which the ion beam passes and that is operable to vary a shape of the gap so as to shield a part of the ion beam extracted from the ion source, wherein the variable slit includes a first slit and a second slit that are disposed on both sides in a thickness direction of the ion beam so as to be opposed to each other with an interval therebetween, wherein the first slit and the second slit respectively include a plurality of small slits that are separated in a width direction of the ion beam, and wherein the small slits are operable to move independently in a thickness direction. 3. An ion implanting apparatus which performs an ion implantation by irradiating an ion beam having passed through a separation slit to a substrate, the ion implanting apparatus comprising:(a) an ion source that generates plasma containing a desired type of ion to be implanted into the substrate;(b) an extraction electrode system that extracts an ion beam having a rectangular section and containing the desired type of ion from the plasma generated from the ion source;(c) a mass-separation electromagnet that performs a mass-separation by bending the extracted ion beam in a thickness direction so as to derive the ion beam containing the desired type of ion;(d) the separation slit that receives the ion beam having passed through the mass-separation electromagnet and allows the desired type of ion to selectively pass therethrough, wherein the separation slit is operable to vary a shape of a gap through which the ion beam passes; and(e) a variable slit that is disposed between the extraction electrode system and the mass-separation electromagnet so as to form a gap through which the ion beam passes and that is operable to vary a shape of the gap so as to shield a part of the ion beam extracted from the ion source, wherein the variable slit includes a first slit and a second slit that are disposed on both sides in a thickness direction of the ion beam so as to be opposed to each other with an interval therebetween, wherein the first slit and the second slit respectively include a plurality of small slits that are separated in a width direction of the ion beam, and wherein the small slits are operable to move independently in a thickness direction. 4. The ion implanting apparatus according to claim 1, further comprising:(e) a beam profile monitor that is disposed on a downstream side of the mass-separation electromagnet in an ion beam travel direction so as to measure a shape of the section of the ion beam upon receiving the ion beam;(f) an ion monitor that is disposed on a downstream side of the separation slit in an ion beam travel direction so as to measure types and ratios of ions contained in the ion beam upon receiving the ion beam having passed through the separation slit; and(g) a control unit that is operable to independently control respective movements of the plurality of small slits and controls the respective small slits so as to obtain desired mass-separation resolution on the basis of measurement information obtained by the beam profile monitor and the ion monitor. 5. The ion implanting apparatus according to claim 2, further comprising:(f) a beam profile monitor that is disposed on the downstream side of the mass-separation electromagnet in an ion beam travel direction so as to measure a shape of the section of the ion beam upon receiving the ion beam; and(g) a control unit that is operable to independently control respective movements of the plurality of small slits, and that predicts a part of the ion beam of which current density becomes relatively high after passing the mass-separation electromagnet among the ion beam received by the variable slit on the basis of measurement information obtained by the beam profile monitor, and controls the respective small slits so as to shield the part of the ion beam by using the respective small slits disposed at a position corresponding to the predicted part. 6. An ion implanting apparatus which performs an ion implantation by irradiating an ion beam having passed through a separation slit to a substrate, the ion implanting apparatus comprising:(a) an ion source that generates plasma containing a desired type of ion to be implanted into the substrate;(b) an extraction electrode system that extracts an ion beam having a rectangular section and containing the desired type of ion from the plasma generated from the ion source;(c) a mass-separation electromagnet that performs a mass-separation by bending the extracted ion beam in a thickness direction so as to derive the ion beam containing the desired type of ion;(d) the separation slit that receives the ion beam having passed through the mass-separation electromagnet and allows the desired type of ion to selectively pass therethrough, wherein the separation slit is operable to vary a shape of a gap through which the ion beam passes, wherein the separation slit includes a first slit and a second slit that are disposed on both sides in a thickness direction of the ion beam so as to be opposed to each other with an interval therebetween, wherein the first slit and the second slit respectively include a plurality of small slits that are separated in a width direction of the ion beam, wherein the small slits are arranged so that a gap through which the ion beam passes is not formed between the small slits that are adjacent to each other in a width direction, and wherein the small slits are operable to move independently in a thickness direction; and(e) a variable slit that is disposed between the extraction electrode system and the mass-separation electromagnet so as to form a gap through which the ion beam passes and that is operable to vary a shape of the gap so as to shield a part of the ion beam extracted from the ion source. 7. The ion implanting apparatus according to claim 6, further comprising:(f) a beam profile monitor that is disposed on a downstream side of the mass-separation electromagnet in an ion beam travel direction so as to measure a shape of the section of the ion beam upon receiving the ion beam;(g) an ion monitor that is disposed on a downstream side of the separation slit in an ion beam travel direction so as to measure types and ratios of ions contained in the ion beam upon receiving the ion beam having passed through the separation slit; and(h) a control unit that is operable to independently control respective movements of the plurality of small slits and controls the respective small slits so as to obtain desired mass-separation resolution on the basis of measurement information obtained by the beam profile monitor and the ion monitor. 8. The ion implanting apparatus according to claim 3, further comprising:(f) a beam profile monitor that is disposed on the downstream side of the mass-separation electromagnet in an ion beam travel direction so as to measure a shape of the section of the ion beam upon receiving the ion beam; and(g) a control unit that is operable to independently control respective movements of the plurality of small slits, and that predicts a part of the ion beam of which current density becomes relatively high after passing the mass-separation electromagnet among the ion beam received by the variable slit on the basis of measurement information obtained by the beam profile monitor, and controls the respective small slits so as to shield the part of the ion beam by using the respective small slits disposed at a position corresponding to the predicted part.