Charged-particle-beam device
View Patent ↗A charged-particle-beam device used for measuring the dimensions, etc., of fine circuit patterns in a semiconductor manufacturing process, wherein corrections are made in the defocusing and astigmatism generated during changes in the operating conditions of a Wien filter acting as a deflector of secondary signals such as secondary electrons, and the display dimensions of obtained images are kept constant. In the charged-particle-beam device, the Wien filter ( 23 ) is arranged between a detector and a lens ( 11 ) arranged on the test-sample side among two stages of lenses for converging a charged-particle beam, and a computing device ( 93 ) is provided for the interlocked control of the Wien filter ( 23 ) and a lens ( 12 ) arranged on the charged-particle-source side among the two stages of lenses.
1. A charged particle beam apparatus comprising:
a charged particle source;
2-stage lenses for converging a primary charged particle beam emitted from the charged particle source on a sample, wherein a first lens arranged on a side of the charged particle source and a second lens arranged on the side of the sample are included;
a deflector that specifies an irradiation position of the primary charged particle beam on the sample;
a detector arranged between the 2-stage lenses to detect a secondary charged particle signal generated by the sample being irradiated with the primary charged particle beam from the sample;
a first Wien filter arranged between the detector and the second lens to deflect the secondary charged particle signal; and
a processor that controls an operating condition of the first Wien filter and a drive current of the first lens in linkage by calculating the drive current to control the first lens based on a deflection amount of the secondary charged particle signal as determined by the controlled operating condition of the first Wien filter.
2. The charged particle beam apparatus according to claim 1 , wherein the processor calculates the action of the first lens by accepting a focused position of the first lens, energy of the primary charged particle beam, and detected electron energy in the detector as input values.
3. The charged particle beam apparatus according to claim 1 , wherein the deflector is arranged between the 2-stage lenses.
4. The charged particle beam apparatus according to claim 1 , further comprising:
a display unit that displays an image obtained from the secondary charged particle signal,
wherein when an operating condition of the first Wien filter is changed, the image is displayed in the display unit without variations of imaging magnification.
5. The charged particle beam apparatus according to claim 1 , further comprising:
a second Wien filter arranged on the side of the charged particle source from the first Wien filter,
wherein the processor controls the first Wien filter, the second Wien filter, and the first lens in linkage.
6. The charged particle beam apparatus according to claim 5 , wherein the processor calculates an action of the first lens from a deflection amount of the secondary charged particle signal by the first Wien filter.
7. The charged particle beam apparatus according to claim 6 , wherein the processor calculates the action of the first lens by accepting a focused position of the first lens, energy of the primary charged particle beam, and detected electron energy in the detector as input values.
8. The charged particle beam apparatus according to claim 7 , further comprising:
a voltage source that applies a voltage to the sample,
wherein the input value of the energy of the primary charged particle beam is a value obtained by adding a value of the voltage applied to the sample to an irradiation voltage to the sample of the primary charged particle beam, and
the input value of the detected electron energy is a value obtained by adding the value of the voltage applied to the sample to the energy of the secondary charged particle signal immediately before being emitted from the sample.
9. The charged particle beam apparatus according to claim 5 , further comprising:
a third lens arranged on the side of the charged particle source from the deflector;
a second deflector arranged between the 2-stage lenses; and
a third Wien filter operated by being linked with the second deflector,
wherein the processor controls the first Wien filter, the second Wien filter, the third Wien filter, and the third lens in linkage.
10. The charged particle beam apparatus according to claim 9 , wherein the processor calculates an action of the first lens and that of the third lens from a deflection amount of the secondary charged particle signal by the first Wien filter and that of the secondary charged particle signal by the third Wien filter.
11. The charged particle beam apparatus according to claim 9 , wherein the processor calculates an action of the third lens from a deflection amount of the secondary charged particle signal by the first Wien filter and that of the secondary charged particle signal by the third Wien filter.
12. The charged particle beam apparatus according to claim 9 , wherein the third lens is an electrostatic lens.
13. The charged particle beam apparatus according to claim 1 , further comprising:
an astigmatic corrector,
wherein the processor controls the first Wien filter and the astigmatic corrector in linkage.
14. The charged particle beam apparatus according to claim 9 , further comprising:
an astigmatic corrector,
wherein the processor controls the first Wien filter, the third Wien filter, and the astigmatic corrector in linkage.