Abstract A particle beam device such as an electron microscope has a predetermined optical axis and means for directing a particle beam at a predetermined angle to an object. The beam-directing means has a first pair of electrical deflecting coils situated at a first plane for deflecting the beam away from the optical axis toward a second plane, the first and second planes each being normal to the optical axis and the second plane being disposed intermediate the first plane and the object. A second pair of electrical deflecting coils are situated at the second plane for deflecting the beam in a direction opposite to the direction of deflection provided by the first pair of deflecting coils so as to direct the beam to the object at the predetermined angle. The first and second deflecting coil pairs deflect the beam in a third plane which is perpendicular to the first and second planes and which contains the optical axis. An additional pair of electrical deflecting coils are situated at least at one of the first and second planes. An electrical supply is connected to the additional pair of coils for supplying the latter with an excitation proportional to the excitation of the first and second pairs of deflecting coils thereby enabling the additional deflecting pair of coils to compensate for undesired deflections of the beam out of the third plane caused by the first and second pairs of deflecting coils.
In a particle beam device such as an electron microscope having a predetermined optical axis and means for directing a particle beam at a predetermined angle to an object, said beam directing means comprising first electrical deflecting means situated at a first plane for deflecting said beam away from the optical axis toward a second plane, said first and second planes each being normal to the optical axis and said second plane being disposed intermediate said first plane and the object, second electrical deflecting means situated at said second plane for deflecting said beam in a direction opposite to the direction of deflection provided by said first deflecting means so as to direct said beam to the object at the predetermined angle, said first and second deflecting means deflecting said beam in a third plane which is perpendicular to said first and second planes and which contains said optical axis, additional electrical deflecting means situated at least at one of said first and second planes, electrical supply means electrically connected to said additional electrical deflecting means for supplying the latter with an excitation proportional to the excitation of said first and second electrical deflecting means, whereby said additional electrical deflecting means compensates for undesired deflections of said beam out of said third plane caused by said first and second electrical deflecting means, third and fourth electrical deflecting means situated at said first and second planes respectively for deflecting said beam in a fourth plane and directing the beam to said object at a predetermined angle and in a predetermined direction, said fourth plane being perpendicular to said third plane and containing said optical axis, and further electrical deflecting means situated at one of said first and second planes, and further electrical supply means electrically connected to said further electrical deflecting means for supplying the latter with an excitation proportional to the excitation of said third and fourth electrical deflecting means, whereby said further electrical deflecting means compensates for undesired deflections oF said beam out of said fourth plane caused by said third and fourth electrical deflecting means.
Claim 2
Dependent Claim
347 words
In a particle beam device such as an electron microscope having a predetermined optical axis and means for directing a particle beam at a predetermined angle to an object, said beam directing means comprising first electrical deflecting means situated at a first plane for deflecting said beam away from the optical axis toward a second plane, said first and second planes each being normal to the optical axis and said second plane being disposed intermediate said first plane and the object, second electrical deflecting means situated at said second plane for deflecting said beam in a direction opposite to the direction of deflection provided by said first deflecting means so as to direct said beam to the object at the predetermined angle, said first and second deflecting means deflecting said beam in a third plane which is perpendicular to said first and second planes and which contains said optical axis, additional electrical deflecting means situated at least at one of said first and second planes, electrical supply means electrically connected to said additional electrical deflecting means for supplying the latter with an excitation proportional to the excitation of said first and second electrical deflecting means, whereby said additional electrical deflecting means compensates for undesired deflections of said beam out of said third plane caused by said first and second electrical deflecting means, third and fourth electrical deflecting means situated at said first and second planes respectively for deflecting said beam in a fourth plane and directing the beam to said object at a predetermined angle and in a predetermined direction, said fourth plane being perpendicular to said third plane and containing said optical axis, and further electrical deflecting means situated at one of said first and second planes, and further electrical supply means electrically connected to said further electrical deflecting means for supplying the latter with an excitation proportional to the excitation of said third and fourth electrical deflecting means, whereby said further electrical deflecting means compensates for undesired deflections oF said beam out of said fourth plane caused by said third and fourth electrical deflecting means.