Charged particle beam device
View Patent ↗The charged particle beam device of this invention separately detects secondary signal particles emitted from the surface of a sample, dark field signal particles scattered within and transmitted through the sample, bright field signal particles transmitted through the sample without being scattered within the sample, and thereby allows the operator to observe the image with an optimum contrast according to applications. In order to detect only the dark field transmitted signal particles scattered within the sample, among the transmitted signal particles obtained by the primary charged particle beams having transmitted through the thin film sample, the device includes a transmitted signal conversion member having an opening through which the bright field transmitted signal particles not being scattered within the sample can pass, and a detection means for detecting signals colliding against the conversion member.
1. A charged particle beam device having a source of charged particles, and a charged particle optical system for focusing primary charged particle beams emitted from said source of charged particles and scanning the primary charged beams on a sample, said device comprising:
a transmitted signal conversion member for emitting secondary charged particles by collisions of charged particles transmitted through the sample, said charged particle optical system including an objective lens, and comprising
a first detector on the side of the charged particle source with respect to the objective lens, and
a second detector below the sample, wherein the objective lens generates a magnetic field in such a manner that secondary charged particles emitted from the sample are not prevented from advancing toward the first detector and signal particles emitted from the transmitted signal conversion member are not prevented from reaching the second detector.
2. The charged particle beam device as claimed in claim 1 , wherein said transmitted signal conversion member comprises an opening, and a transmitted signal particle detection means that is disposed at a position to detect transmitted signal particles having passed through said opening of said transmitted signal conversion member.
3. The charged particle beam device as claimed in claim 2 , wherein an aperture for obstructing part of the transmitted signal particles reaching said transmitted signal particle detection means is disposed between said transmitted signal particle detection means and said transmitted signal conversion member.
4. The charged particle beam device as claimed in claim 2 , wherein a power supply for applying zero voltage or a positive voltage to said opening is provided.
5. The charged particle beam device as claimed in claim 4 , wherein said power supply is a variable source capable of adjusting the applied voltage.
6. The charged particle beam device as claimed in claim 1 , wherein a wall is provided around a sample mounting area of a sample mount, upon which the sample is to be placed.
7. The charged particle beam device as claimed in claim 1 , wherein said transmitted signal conversion member is disposed horizontally.