Patent Number: 
Section: claims

1. An ion implantation method of implanting ions into a substrate using both a ribbon-like ion beam in which, with or without performing an X direction sweep, a dimension in an X direction is larger than a dimension in a Y direction that is orthogonal to the X direction, and a mechanical scan of the substrate in a direction intersecting with a principal face of the ion beam, said method comprising:calculating a scan number of the substrate as an integer value in which digits after a decimal point are truncated by using a beam current of the ion beam, a dose amount to the substrate, and a reference scan speed which is used as a reference for calculating a scan number of the substrate;determining whether the calculated scan number is 2 or more or not; if the scan number is smaller than 2, aborting a process of obtaining a practical scan number and a practical scan speed; if the scan number is equal to or larger than 2, determining whether the calculated scan number is even or odd; if the scan number is even, setting the current scan number as the practical scan number; and, if the scan number is odd, obtaining an even scan number which is smaller by 1 than the odd scan number, and setting the obtained even scan number as the practical scan number;calculating the practical scan speed of the substrate by using the practical scan number, the beam current, and the dose amount; andperforming ion implantation on the substrate in accordance with the practical scan number and the practical scan speed. 2. An ion implantation apparatus for implanting ions into a substrate using both a ribbon-like ion beam in which, with or without performing an X direction sweep, a dimension in an X direction is larger than a dimension in a Y direction that is orthogonal to the X direction, and a mechanical scan of the substrate in a direction intersecting with a principal face of the ion beam, said apparatus comprising:a controlling device having functions of: (a) calculating a scan number of the substrate, as an integer value in which digits after a decimal point are truncated by using a beam current of the ion beam, a dose amount to the substrate, and a reference scan speed which is used as a reference for calculating a scan number of the substrate; (b) determining whether the calculated scan number is 2 or more or not; if the scan number is smaller than 2, aborting a process of obtaining a practical scan number and a practical scan speed; if the scan number is equal to or larger than 2, determining whether the calculated scan number is even or odd; if the scan number is even, setting the current scan number as the practical scan number; and, if the scan number is odd, obtaining an even scan number which is smaller by 1 than the odd scan number, and setting the obtained even scan number as the practical scan number; (c) calculating the practical scan speed of the substrate by using the practical scan number, the beam current, and the dose amount; and (d) performing ion implantation on the substrate in accordance with the practical scan number and the practical scan speed. 3. An ion implantation method of implanting ions into a substrate using both a ribbon-like ion beam in which, with or without performing an X direction sweep, a dimension in an X direction is larger than a dimension in a Y direction that is orthogonal to the X direction, a mechanical scan of the substrate in a direction intersecting with a principal face of the ion beam, and performance of ion implantation while, during a period when the ion beam does not impinge on the substrate, rotating the substrate by a step of 360/m deg. about a center portion of the substrate, and dividing one rotation of the substrate into a plurality m of implanting steps, said method comprising:calculating a scan number per implanting step of the substrate as an integer value in which digits after a decimal point are truncated by using a beam current of the ion beam, a dose amount to the substrate, a implanting step number, and a reference scan speed which is used as a reference for calculating a scan number per implanting step of the substrate;determining whether the calculated scan number per implanting step is 1 or more or not; if the scan number is smaller than 1, aborting a process of obtaining a practical scan number per implanting step and a practical scan speed; if the scan number is equal to or larger than 1, determining whether the calculated scan number per implanting step is even or odd; if the scan number is even, setting the current scan number as the practical scan number per implanting step; if the scan number is odd, determining whether the scan number is 1 or not; if the scan number is 1, setting the current scan number as a practical scan number per implanting step; and, if the scan number is not 1, obtaining an even scan number which is smaller by 1 than the odd scan number, and setting the obtained even scan number is set as the practical scan number per implanting step;calculating the practical scan speed of the substrate by using the practical scan number per implanting step, the beam current, the dose amount, and the implanting step number; andperforming ion implantation on the substrate in accordance with the practical scan number per implanting step and the practical scan speed. 4. An ion implantation apparatus for implanting ions into a substrate using all of a ribbon-like ion beam in which a dimension in an X direction is larger than a dimension in a Y direction that is orthogonal to the X direction, a mechanical scan of the substrate in a direction intersecting with a principal face of the ion beam, and performance of ion implantation while, during a period when the ion beam does not impinge on the substrate, rotating the substrate by a step of 360/m deg. about a center portion of the substrate, and dividing one rotation of the substrate into a plurality m of implanting steps, said apparatus comprising:a controlling device having functions of: (a) calculating a scan number per implanting step of the substrate, as an integer value in which digits after a decimal point are truncated by using a beam current of the ion beam, a dose amount to the substrate, a number of the implanting steps, and a reference scan speed which is used as a reference for calculating a scan number per implanting step of the substrate; (b) determining whether the calculated scan number per implanting step is 1 or more or not; if the scan number is smaller than 1, aborting a process of obtaining a practical scan number per implanting step and a practical scan speed; if the scan number is equal to or larger than 1, determining whether the calculated scan number per implanting step is even or odd; if the scan number is even, setting the current scan number, as the practical scan number per implanting step; if the scan number is odd, determining whether the scan number is 1 or not; if the scan number is 1, setting the current scan number, as the practical scan number per implanting step; and, if the scan number is not 1, obtaining an even scan number which is smaller by 1 than the odd scan number, and setting the obtained even scan number as the practical scan number per implanting step; (c) calculating a practical scan speed of the substrate by using the practical scan number per implanting step, the beam current, the dose amount, and the implanting step number; and (d) performing ion implantation on the substrate in accordance with the practical scan number per implanting step and the practical scan speed.