CHARGED PARTICLE LITHOGRAPHY APPARATUS AND METHOD OF GENERATING VACUUM IN A VACUUM CHAMBER
The invention relates to a charged particle lithography apparatus with a charged particle source for creating one or more charged particle beams, a charged particle projector for projecting the beams onto a wafer; and a moveable wafer stage for carrying the wafer. The charged particle source, charged particle projector, and moveable wafer stage are disposed in a common vacuum chamber forming a vacuum environment. The vacuum chamber further has an opening for loading wafers into the chamber and a door.
1 . A charged particle lithography apparatus comprising:
a charged particle source for creating one or more charged particle beams;
a charged particle projector for projecting the beams onto a wafer; and
a moveable wafer stage for carrying the wafer;
wherein the charged particle source, charged particle projector, and moveable wafer stage are disposed in a common vacuum chamber forming a vacuum environment, and wherein the vacuum chamber comprises an opening for loading wafers into the chamber and a door.
2 - 5 . (canceled)
6 . The apparatus of claim 1 , wherein the door forms one entire wall of the chamber.
7 . (canceled)
8 . The apparatus of claim 1 , wherein the interior surface of the walls of the chamber are covered with a mu metal.
9 . The apparatus of claim 1 , wherein the walls of the chamber comprise a composite structure including one or more layers of mu metal.
10 . The apparatus of claim 1 , wherein the walls of the chamber comprise a composite structure including a layer of aluminum and a layer of mu metal, the layer of aluminum being separated from the layer of mu metal by a plurality of spacing members.
11 . The apparatus of claim 10 , wherein the composite structure further includes a further layer of mu metal, separated from the layer of mu metal by a plurality of further spacing members.
12 . The apparatus of claim 11 , further comprising one or more electrically insulating layers for insulating the mu metal layers.
13 . The apparatus of claim 1 , wherein parts protruding into the chamber are covered by a bellows structure comprised of or covering one or more layers of mu metal.
14 . The apparatus of claim 13 , wherein the bellows structure is coupled to the one or more layers of mu metal.
15 . The apparatus of claim 13 , wherein the bellows structure is coupled to a wall of the chamber.
16 . The apparatus of claim 1 , wherein the walls of the chamber are glued together.
17 . The apparatus of claim 1 , wherein the vacuum chamber is provided with a lift system for opening the door by lifting the door in a vertical direction or a predominantly vertical direction.
18 . The apparatus of claim 17 , wherein the lift system is provided with guiding elements for guiding the door at least in a first stage of opening in both a vertical and a horizontal direction.
19 . The apparatus of claim 17 , wherein the lift system comprises a hoist or winch for lifting the door via a flexible pull member.
20 . The apparatus of claim 19 , further comprising guiding elements for guiding the flexible pull member and transferred lifting force to the door.
21 - 22 . (canceled)
23 . The apparatus claim 1 , wherein the vacuum chamber is provided with at least one arm on each side of the door for opening the door in a predominantly vertical direction, the arms extending downwards from a hinging point to connect to the door.
24 . The apparatus of claim 23 , comprising at least two arms on each side of the door arranged in a parallelogram construction.
25 . The apparatus of claim 23 , further comprising an actuation member extending obliquely upwardly to pivotally connect to one of the arms.
26 . The apparatus of claim 25 , wherein the actuation member comprises an electric screw spindle.
27 - 28 . (canceled)
29 . The apparatus of claim 1 , wherein the source is situated in a source chamber.
30 . The apparatus of claim 29 , wherein the source chamber comprises a getter pump.
31 . The apparatus of claim 29 , wherein the source chamber is connected to the vacuum chamber by means of a valve actuated by an actuation unit.
32 . The apparatus of claim 31 , wherein the actuation unit comprises a piezo-electric actuator.
33 . The apparatus of claim 1 , wherein one or more subsystems of the apparatus are constructed in self-contained and removable modules, the removable modules comprising at least one each of:
an illumination optics module including a charged particle beam source and beam collimating system;
an aperture array and condenser lens module including an aperture array and condenser lens array;
a beam switching module including a beamlet blanker array; and
a projection optics module including a beam stop array, beam deflector array, and one or more projection lens arrays.
34 . The apparatus of claim 33 , further comprising a wafer table for supporting a wafer, a chuck for holding the wafer table, and a short stroke stage element and a long stroke stage element.
35 . The apparatus of claim 1 , wherein the chamber is provided with ports for admitting electrical, optical, and/or power cables or wires into the chamber, the ports providing a seal around the cables or wires.
36 . (canceled)
37 . The apparatus of claim 33 , wherein a patch panel is provided within the vacuum chamber, the patch panel comprising one or more connectors for removably connecting one or more connections of the removable modules.
38 . The apparatus of claim 37 , wherein the chamber is provided with one or more ports for admitting the one or more connections of the removable modules into the chamber.
39 . The apparatus of claim 35 , wherein at least one of the ports comprises a lid and one or more mu metal caps.
40 . The apparatus of claim 39 , wherein the port lid and the one or more mu metal caps are arranged as a unit.
41 . The apparatus of claim 40 , wherein the port lid, one or more mu metal caps, the electrical, optical, and/or power cables or wires passing through the port, and a connector terminating the cables or wires, are arranged to be removed and replaced as a unit.
42 . The apparatus of claim 39 , wherein the one or more mu metal caps are pressed against corresponding mu metal wall layers when the port lid is closed.
43 . The apparatus of claim 1 , wherein the chamber is provided with one or more vacuum pump openings, the openings having a flap or valve comprising mu metal.
44 . An arrangement comprising the charged particle lithography apparatus of claim 1 and a frame for supporting the vacuum chamber of the charged particle lithography apparatus, wherein the vacuum chamber and the frame are coupled to each other via a vibration damping element.
45 . The arrangement of claim 44 , wherein the vibration damping element is an air mount.