Patent Number: 
Section: claims

1. A plasma source comprising:a chamber body inside which plasma is generated;a first mirror magnet and a second mirror magnet disposed around the chamber body at positions spaced apart from each other along a first direction; anda cusp magnet disposed around the chamber body at a position between the first and second mirror magnets in the first direction, wherein:the first mirror magnet comprises a plurality of first permanent magnets which are arranged around the chamber body in a plane perpendicular to the first direction with a first space between adjacent ones of the first permanent magnets, each of the first permanent magnets having a first polarity on a chamber body side of the first permanent magnet,the second mirror magnet comprises a plurality of second permanent magnets which are arranged around the chamber body in the plane perpendicular to the first direction with a second space between adjacent ones of the second permanent magnets, each of the second permanent magnets having a second polarity on a chamber body side of the second permanent magnet; andthe cusp magnet comprises a plurality of cusp permanent magnets which are arranged around the chamber body in the plane perpendicular to the first direction with a cusp space between adjacent ones of the cusp permanent magnets, the cusp permanent magnets having polarities that alternate around the chamber body between the first polarity and a second polarity; wherein the second polarity is different from the first polarity;a plurality of cooling medium flow passage provided in the first space, the second space, and the cusp space. 2. The plasma source as recited in claim 1, wherein the first space, the second space, and the cusp space are aligned in the first direction. 3. The plasma source as recited in claim 1, wherein the cooling medium flow passage comprises a cooling medium turnaround passage. 4. The plasma course as recited in claim 3, wherein the cooling medium turnaround passage is formed in a ring shape, square shape, or a plurality of arc shapes. 5. The plasma source as recited in claim 1, wherein: a portion of the first spaces, a corresponding portion of the second spaces, and a corresponding portion of the cusp spaces form an inflow set, and remaining portions of each of the first spaces, the second spaces, and the cusp spaces form an outflow set, and the plurality of cooling medium flow passage comprises a cooling medium inflow passage that is connected to the inflow set, and a cooling medium outflow passage that is connected to the outflow set. 6. The plasma source as recited in claim 5, wherein the cooling medium flow passage comprises a cooling medium turnaround passage. 7. The plasma course as recited in claim 6, wherein the cooling medium turnaround passage is formed in a ring shape, square shape, or a plurality of arc shapes. 8. The plasma source as recited in claim 1, wherein: the chamber body comprises a first end formed with an opening for releasing therethrough ions or electrons from plasma generated inside the chamber body, and input and output of a cooling medium with respect to the cooling medium flow passage are performed through a second end of the chamber body located on a side opposite to the first end in the first direction. 9. The plasma source as recited in claim 8, wherein the first end of the chamber body has a cooling medium turnaround passage to which one end of the cooling medium flow passage is connected. 10. A plasma source comprising:a chamber body inside which plasma is generated;a first mirror magnet, a second mirror magnet, and a cusp magnet provided around the chamber body and spaced apart in an axial direction thereof, each comprising a plurality of permanent magnets radially spaced apart from each other to form spaces between adjacent permanent magnets thereof;a plurality of cooling medium flow passages provided in the spaces that passes a cooling medium for cooling the chamber body;a plurality of inflow passages formed at a first end of the chamber body in the axial direction and connected to cooling medium flow passages provided in a portion the spaces of the first mirror magnet, the second mirror magnet, and the cusp magnet;a plurality of outflow passages formed at the first end and connected to cooling medium flow passages provided in a remaining portion of the spaces of the first mirror magnet, the second mirror magnet, and the cusp magnet; anda turnaround passage formed at a second end of the chamber body opposite to the first end and connected to the cooling medium flow passages provided in both the portion and the remaining portion of the spaces. 11. The plasma source as recited in claim 10, wherein the spaces of the permanent magnets of the first mirror magnet, the second mirror magnet, and the cusp magnet are aligned in the axial direction. 12. The plasma source as recited in claim 10, wherein the inflow passage is formed radially around the chamber body at the first end of the chamber body, and the outflow passage is formed radially around the chamber body at the first end. 13. The plasma course as recited in claim 10, wherein the turnaround passage is formed in a ring shape, square shape, or a plurality of arc shapes around the chamber body at the second end. 14. The plasma source as recited in claim 10, wherein the chamber body further comprises an opening at the second end thereof. 15. The plasma source as recited in claim 1, wherein the first direction is an axial direction of the chamber body.