Patent Number: 
Section: claims

1. A charged-particle beam system comprising:a source of a beam of charged particles;an objective lens;an aberration corrector for correcting third-order spherical aberration, the aberration corrector being mounted between the source of the beam and the objective lens, the aberration corrector defining an image point; anda transfer lens for correcting fifth-order spherical aberration and third-order chromatic aberration, the transfer lens being so placed that a principal plane of the transfer lens is located at the image point of the aberration corrector. 2. A charged-particle beam system as set forth in claim 1, wherein strength of said transfer lens is so set that an aberration generation point in the aberration corrector is projected at a front focal point of the objective lens or at a coma-free point. 3. A charged-particle beam system as set forth in claim 1 or 2, wherein said aberration corrector corrects the third-order spherical aberration, and wherein the charged-particle beam system has a function of correcting the fifth-order spherical aberration and third-order chromatic aberration while holding a trajectory of the beam of the charged particles assumed when the third-order spherical aberration was corrected. 4. A charged-particle beam system as set forth in claim 3, wherein the charged-particle beam system has a function of adjusting strength of said transfer lens such that the fifth-order spherical aberration and third-order chromatic aberration are corrected. 5. A charged-particle beam system as set forth in claim 3, wherein the charged-particle beam system has a function of controlling strength of said transfer lens to adjust resolution of a scanned image. 6. A charged-particle beam system as set forth in claim 3, wherein the charged-particle beam system has a function of controlling strength of said transfer lens to adjust contrast of a scanned image. 7. A charged-particle beam system comprising:a source of a beam of charged particles;a deceleration objective lens;an aberration corrector for correcting third-order spherical aberration, the aberration corrector being mounted between the source of the beam and the objective lens, the aberration corrector defining an image point; andan additional accelerating lens for correcting fifth-order spherical aberration and third-order chromatic aberration, the additional accelerating lens having a principal plane placed at the image point of the aberration corrector. 8. A charged-particle beam system as set forth in claim 7, wherein strength of said additional accelerating lens is so set that an aberration generation point in the aberration corrector is projected at a front focal point of the objective lens or at a coma-free point. 9. A charged-particle beam system as set forth in claim 7 or 8, wherein said aberration corrector corrects the third-order spherical aberration, and wherein the charged-particle beam system has a function of correcting the fifth-order spherical aberration and third-order chromatic aberration while holding a trajectory of the beam of the charged particles assumed when the third-order spherical aberration was corrected. 10. A charged-particle beam system as set forth in claim 9, wherein the charged-particle beam system has a function of adjusting strength of said additional accelerating lens such that the fifth-order spherical aberration and third-order chromatic aberration are corrected. 11. A charged-particle beam system comprising:a source of a beam of charged particles;an objective lens of a superimposed electric and magnetic field type;an aberration corrector for correcting third-order spherical aberration, the aberration corrector being mounted between the source of the beam and the objective lens, the aberration corrector defining an image point; andan additional accelerating lens for correcting the fifth-order spherical aberration and third-order chromatic aberration, the additional accelerating lens having a principal plane placed at the image point of the aberration corrector. 12. A charged-particle beam system as set forth in claim 11, wherein strength of said additional accelerating lens is so set that an aberration generation point in the aberration corrector is projected at a front focal point of the objective lens or at a coma-free point. 13. A charged-particle beam system as set forth in claim 12, wherein said aberration corrector corrects the third-order spherical aberration, and wherein the charged-particle beam system has a function of correcting the fifth-order spherical aberration and third-order chromatic aberration while holding a trajectory of the beam of the charged particles assumed when the third-order spherical aberration was corrected. 14. A charged-particle beam system as set forth in claim 13, wherein the charged-particle beam system has a function of adjusting strength of said additional accelerating lens such that the fifth-order spherical aberration and third-order chromatic aberration are corrected. 15. A charged-particle beam system as set forth in any one of claims 1, 7 and 11, wherein the aberration corrector is composed of four stages of electrostatic multipole elements and two stages of magnetic quadrupole elements for superimposing a magnetic potential distribution on an electric potential distribution created by two central stages of electrostatic quadrupole elements of the four stages, the magnetic potential distribution being analogous to the electric potential distribution, and wherein said charged-particle beam system further includes an objective lens for focusing the beam of charged particles onto a specimen, means for applying a decelerating voltage to the specimen, a manipulation portion permitting a human operator to modify the accelerating voltage of the beam or the working distance between the objective lens and the specimen, and a control portion for controlling the multipole elements based on manipulation of the manipulation portion or on settings.