Charged particle beam apparatus
The present invention provides apparatuses to inspect small particles on the surface of a sample such as wafer and mask. The apparatuses provide both high detection efficiency and high throughput by forming Dark-field BSE images. The apparatuses can additionally inspect physical and electrical defects on the sample surface by form SE images and Bright-field BSE images simultaneously. The apparatuses can be designed to do single-beam or even multiple single-beam inspection for achieving a high throughput.
1. A device of detecting electrons generated from a surface of a sample on a sample stage, comprising:
a first detector having a through hole and inclined towards said sample stage;
a primary electron beam source, generating a primary electron beam passing through said through hole, and illuminating said surface of said sample by oblique incidence, wherein said surface generates backscattered electrons (BSEs) and secondary electrons when illuminated, and said first detector collects BSEs traveling towards said first detector to generate a Dark-field BSE image; and
a first electrode adjacent to a path of said primary electron beam, wherein said first electrode attracts and prevents secondary electrons generated from said surface of said sample from hitting said first detector;
wherein, said first detector is on a first plane at a first angle relative to said sample stage, said first electrode is on a second plane at a second angle relative to said sample stage, and said first plane and said second plane are intersecting;
wherein, a first virtual axis, perpendicular to said sample stage and intersecting said sample, intersects said first electrode, and said first detector is adjacent to said first virtual axis; and
wherein the sample stage has a first voltage potential and the first detector has a second voltage potential, wherein said first voltage potential and said second voltage potential are equal.
2. The device according to claim 1 , wherein said first electrode has a grid structure so as to attract and make said secondary electrons pass through.
3. The device according to claim 2 , further comprising a second detector behind said first electrode so as to detect said secondary electrons therethrough.
4. The device according to claim 3 , further comprising a third detector on a reflection side of said primary electron beam, wherein said third detector is inclined towards said sample stage so as to collect BSEs generated from said surface of said sample by said primary electron beam and traveling towards said reflection side.
5. The device according to claim 1 , further comprising a third detector on a reflection side of said primary electron beam, wherein said third detector is inclined towards said sample stage so as to collect BSEs generated from said surface of said sample by said primary electron beam and traveling towards said reflection side.
6. The device according to claim 1 , further comprising a second electrode in front of said first detector, wherein said second electrode has a grid structure so as to repel and prevent said secondary electrons from passing through and make the Dark-field BSEs pass through.
7. The device according to claim 1 , wherein the first electrode has a third voltage potential, wherein said third voltage potential is greater than said first voltage potential.