Charged particle beam source and charged particle beam system
Provided is a charged particle beam source having an emitter that can be replaced easily. The charged particle beam source includes an electron gun chamber; a first unit including both a supportive insulative member mechanically supporting a cable and a first set of terminals electrically connected to the cable; and a second unit including both the emitter that releases charged particles and a second set of terminals electrically connected to the emitter. The chamber has a side wall provided with a through-hole in which the first unit is secured. The second unit can be detachably mounted to the first unit. Within the chamber, the emitter is placed on an optical axis, so that the first and second sets of terminals are brought into contact with each other.
1 . A charged particle beam source configured to release a charged particle beam aligned with an optical axis, comprising:
a chamber having a side wall;
a first unit comprising a supportive insulative member mechanically supporting a cable, a first set of terminals electrically connected to the cable, and a support member comprising a central axis coincident with the optical axis; and
a second unit comprising an emitter for emitting charged particles, a second set of terminals electrically connected to the emitter, an electrode positioned under the emitter and provided with a hole for passage of electrons released from the emitter, and a third terminal electrically connected to the electrode, the second unit configured to be detachably mounted to the first unit;
wherein the first unit is secured in a through-hole formed in the side wall of the chamber;
wherein the first unit includes a fourth terminal;
wherein the first set of terminals is elongated in a direction orthogonal to the optical axis;
wherein the second set of terminals is elongated in a direction orthogonal to the optical axis when the second unit is inserted into the support member; and
wherein the second unit is configured to be inserted into the support member such that the emitter is placed on the optical axis within the chamber, whereby the first and second sets of terminals are brought into contact with each other and the third and fourth terminals are brought into contact with each other.
2 . The charged particle beam source as set forth in claim 1 , wherein the support member provides mechanical support of said second unit.
3 . The charged particle beam source as set forth in claim 1 , further comprising a cover that closes off said chamber.
4 . The charged particle beam source as set forth in claim 3 , wherein said second unit is mounted to said cover which in turn is mounted to said chamber, whereby said emitter is placed on said optical axis and said first and second sets of terminals are brought into contact with each other.
5 . The charged particle beam source as set forth in claim 3 , further comprising a vacuum pump mounted to said cover.
6 . The charged particle beam source as set forth in claim 5 , wherein said vacuum pump is a getter pump.
7 . The charged particle beam source as set forth in claim 1 , wherein each of said second set of terminals is a resilient body.
8 . The charged particle beam source as set forth in claim 7 , wherein each of said second set of terminals is a leaf spring.
9 . The charged particle beam source as set forth in claim 1 , further comprising a third unit which is replaceable with said second unit.
10 . The charged particle beam source as set forth in claim 9 , wherein said second unit and said third unit utilize different mechanisms of electron emission.
11 . The charged particle beam source as set forth in claim 10 , wherein said second unit constitutes a Schottky emission gun, a cold field emission gun, or a thermionic emission gun, and wherein said third unit constitutes a Schottky emission gun, a cold field emission gun, or a thermionic emission gun.
12 . The charged particle beam source as set forth in claim 10 , wherein the emitter of said second unit and the emitter of said third unit are of different types.
13 . The charged particle beam source as set forth in claim 12 , wherein the emitter of said second unit is made of lanthanum hexaboride, and wherein the emitter of said third unit is made of tungsten.
14 . A charged particle beam system including a charged particle beam source as set forth in claim 1 .