Testing apparatus using charged particles and device manufacturing method using the testing apparatus
A system for further enhancing speed, i.e. improving throughput in a SEM-type inspection apparatus is provided. An inspection apparatus for inspecting a surface of a substrate produces a crossover from electrons emitted from an electron beam source 25•1 , then forms an image under a desired magnification in the direction of a sample W to produce a crossover. When the crossover is passed, electrons as noises are removed from the crossover with an aperture, an adjustment is made so that the crossover becomes a parallel electron beam to irradiate the substrate in a desired sectional form. The electron beam is produced such that the unevenness of illuminance is 10% or less. Electrons emitted from the sample W are detected by a detector 25•11.
1. An electron beam apparatus comprising:
means for applying an electron beam to a sample;
means for macro-projecting electrons, which obtained information of the surface of said sample with application of said electron beam to said sample, to form an image on a detector; and
means for synthesizing as an image said electrons made to form an image on the detector,
wherein the shape of the irradiation area in which said electron beam is applied to said sample is approximately symmetric with respect to two axes orthogonal to the optical axis of said electron beam,
the illuminance of said electron beam in said irradiation area is uniform,
said means for applying an electron beam and said means for forming an image are an optical system comprised of an electrostatic lens,
said means for synthesizing comprises means for multiplying said electrons, means for converting said electrons multiplied by said multiplying means into light, and a TDI sensor for converting light from said means for converting electrons into light into electric signals for images,
the voltage of said electrostatic lens is adjusted to determine a pixel size on the surface of said sample for obtaining a desired magnification of macro-projection based on the pixel size of said TDI sensor,
said means for synthesizing is provided with a vacuum column having a feed-through flange, and
said electrical signals for images are supplied through said feed-through flange to a TDI camera disposed outside of the vacuum column.
2. An electron beam apparatus according to claim 1 , further comprising:
means for guiding electrons, which obtained information of the surface of said sample with application of the electron beam to said sample, to a detector; and
means for synthesizing said electrons guided to the detector as an image,
wherein the number of incident electrons required for obtaining an image of maximum luminance is 1000/pixel.
3. The electron beam apparatus according to claim 2 , wherein the line frequency of said detector is 300 kHz to 1500 kHz, and said TDI sensor has a pixel number of 2048 to 4096, a tap number of 32 to 128, and a sensitivity of 1000 DN/(nJ/cm 2 ) to 40000 DN/(nJ/cm 2 ).
4. The electron beam apparatus according to claim 1 , wherein said electrons are minor electrons reflected near the surface of said sample.
5. The electron beam apparatus according to claim 1 , wherein the pixel size of said TDI sensor is equal to or smaller than a size that is twice as large as the size of an inspection object so that the inspection object existing on said sample can be found.
6. The electron beam apparatus according to claim 1 , wherein the pixel size of said TDI sensor is a pixel size equal to or smaller than a value obtained by magnifying a design rule by a factor.
7. The electron beam apparatus according to claim 6 , wherein said design rule shows a half pitch of wiring in the case where said sample is a memory, and shows a gate length in the case where said sample is a logic.
8. An electron beam apparatus comprising:
means for applying an electron beam to a sample;
means for macro-projecting electrons, which obtained information of the surface of said sample with application of said electron beam to said sample, to form an image on a detector; and
means for synthesizing as an image said electrons made to form an image on the detector,
wherein the illuminance of said electron beam in said irradiation area is uniform,
said means for forming an image is an optical system comprised of an electrostatic lens,
means for separating said electron beam from said electrons is a deflector using an electric field and a magnetic field,
the center of the image formed by macro-projection on said detector and the center of said electrostatic lens are on a common axis,
in a section between said deflector and said sample, said electron beam has said common axis as an optical axis, and said optical axis of said electron beam is approximately perpendicular to said sample,
said means for synthesizing comprises means for converting light generated by said electrons to electrical signals for images and is provided within a vacuum column having a feed-through flange, and
said electrical signals for images are supplied through said feed-through flange to a TDI camera disposed outside of the vacuum column.
9. The electron beam apparatus according to claim 8 , wherein said electrons are mirror electrons reflected near the surface of said sample.
10. The electron beam apparatus according to claim 8 , wherein said optical system comprises two pairs of objective lenses, two pairs of intermediate lenses and two pair of projection lenses, and reduces at least one of chromatic aberration, a spherical aberration and a coma aberration generated in relation to image formation.
11. The electron beam apparatus according to claim 8 , wherein said electrons are guided to said detector without being deflected by said deflector.
12. The electron bean apparatus according to claim 8 , wherein said electrons are made to form an image at the center of said deflector by said objective lens.
13. The electron beam apparatus according to claim 8 , wherein energy when said electron bean, is applied to said sample is controlled.