Particle beam device with a particle source to be operated in high vacuum and cascade-type pump arrangement for such a particle beam device

• US 20040076529A1
• Filed: 01/06/2003
• Published: 04/22/2004
• Est. Priority Date: 07/07/2000
• Status: Active Grant

• Current Assignee: Carl Zeiss NTS GmbH (Carl-Zeiss-Stiftung)
• Original Assignee: Carl Zeiss NTS GmbH (Carl-Zeiss-Stiftung)
• Inventors: Drexel, Volker, Gnauck, Peter
• Granted Patent: US 6,872,956 B2
• Time in Patent Office: Days
• US Class Current: 417/250
• CPC Class Codes: F04D 19/046 Combinations of two or more different types of pumps
• CPC Class Codes: F04D 25/00 Pumping installations or systems controlling F04D27/00
• CPC Class Codes: H01J 2237/188 Differential pressure
• CPC Class Codes: H01J 2237/2605 operating at elevated pressures, e.g. atmosphere
• CPC Class Codes: H01J 37/18 Vacuum locks ; Means for obtaining or maintaining the desired pressure within the vessel

Abstract

A cascade type pump arrangement for a particle beam device has first and second turbomolecular pumps, wherein an outlet of the second turbomolecular pump is forepumped by an intermediate pressure region situated between a main pump port and an outlet of the first turbomolecular pump. The particle beam device has a particle beam source operated in ultra high vacuum and a specimen chamber operated at pressures from high vacuum at least up to 1 hPa.

Claims

1. Cascade-type pump arrangement for a particle beam device with first and second turbomolecular pumps (13), (14), wherein the outlet (26) of the second turbomolecular pump (13) is forepumped by an intermediate pressure region (24) situated between the main pump port (21) and the outlet (25) of the first turbomolecular pump (14).

2. Cascade-type pump arrangement according to claim 1, wherein the first turbomolecular pump (14) is a split flow pump with a connecting port (22) to the drag stage (24), and the outlet (26) of the second turbomolecular pump (13) is connected to the drag stage (24) of the first turbomolecular pump (14).

3. Pump arrangement according to claim 1, wherein a further forepump (16) is provided for forepumping the outlet (25) of the first turbomolecular pump (14).

4. Particle beam device, which has a particle beam source (3) to be operated in ultra high vacuum, and a specimen chamber (1) which can be operated at pressures from high vacuum at least up to 1 hPa, and wherein a cascade-type pump arrangement according to claim 1 is provided.

5. Particle beam device according to claim 4, wherein exactly two further intermediate pressure regions (7), (8) are provided between the ultra high vacuum region (6) of the particle source and the specimen chamber (1).

6. Particle beam device according to claim 4, wherein the pressure region adjacent to the ultra high vacuum region (6) is pumped by means of the second turbomolecular pump (13).

7. Particle beam device according to claim 4, wherein the first turbomolecular pump (14) is simultaneously connected, by means of the main pump port (21), directly to the pressure region (8) adjacent to the specimen chamber (1).

8. Particle beam device according to claim 7, wherein the forepump (16) is connected directly to the specimen chamber (1) by means of a valve (17).

9. Particle beam device according to claim 4, wherein the first turbomolecular pump (14) is additionally connected directly to the specimen chamber (1) by means of a further valve (19).

10. Particle beam device according to claim 8, wherein a second forepump (20) is provided and is connected to the specimen chamber (1).

11. Particle beam device according to claim 4, wherein an ion getter pump (12) is provided for evacuating the ultra high vacuum region (6).