Ion implanter and method of controlling ion implanter

An ion implanter comprising:

• an ion beam generating unit that includes an ion source, an extraction electrode, and a mass analyzer,
• wherein the mass analyzer includes
• a mass analyzing magnet that applies a magnetic field to ions extracted from the ion source by the extraction electrode to deflect the ions,
• a mass analyzing slit that is provided downstream of the mass analyzing magnet and allows an ion of a desired ion species among the deflected ions to selectively pass, and
• a lens device that is provided between the mass analyzing magnet and the mass analyzing slit and applies a magnetic field to the ion beam directed toward the mass analyzing slit to adjust the convergence or divergence of a ion beam, and
• an intensity of the magnetic field applied to the ion beam passing through the mass analyzing magnet is proportional to (2mE)½/q, and an intensity applied to the ion beam passing through the lens device is proportional to E/q, where E is an energy, m is a mass, and q is a charge of a target ion.

A method of controlling an ion implanter including an ion beam generating unit that includes an ion source, an extraction electrode, and a mass analyzer,

• wherein the mass analyzer includes
• a mass analyzing magnet that applies a magnetic field to ions extracted from the ion source by the extraction electrode to deflect the ions,
• a mass analyzing slit that is provided downstream of the mass analyzing magnet and allows an ion of a desired ion species among the deflected ions to selectively pass, and
• a lens device that is provided between the mass analyzing magnet and the mass analyzing slit and applies at least one of a magnetic field and an electric field to the ion beam directed toward the mass analyzing slit to adjust a convergence or divergence of the ion beam, and
• the method comprises
• calculating mass resolution of the mass analyzer which resolves the ion passing through the mass analyzing slit, and
• changing a focal point of the ion beam, which passes through the mass analyzing slit, in a predetermined adjustable range between an upstream side and a downstream side of the mass analyzing slit with the lens device to increase mass resolution in a case in which the calculated mass resolution is smaller than a target value.