Patent Number: 062657232
Section: claims

1. A magnetic shield apparatus comprising: a magnetic shield room having an opening to shield external magnetism;  a tubular member made of a magnetic shield material and attached to said opening to project from said magnetic shield room by a first predetermined length; and  a flange portion made of a magnetic shield material and formed around a distal end portion of said tubular member to be spaced apart therefrom by a second predetermined length.  said tubular member has a rectangular section and said opening of said tubular member has a rectangular shape, and  said flange portion is constituted by four bent portions formed along four sides of said distal end portion of said tubular member.  said tubular member has a rectangular section and said opening of said tubular member has a rectangular shape, and  said flange portion has a rectangularly annular shape corresponding to four sides of said distal end portion of said tubular member.  said magnetic shield room stores an electron beam (EB) exposure unit for drawing a pattern on a photoresist for a sample by using an electron beam, and a loading/unloading portion for transferring the sample with respect to said EB exposure unit.  said magnetic shield room has an inner wall adhered with a magnetic shield material, and  said tubular member made of said magnetic shield material is connected to said magnetic shield material of said magnetic shield room. 2. An apparatus according to claim 1, wherein the first predetermined length of said tubular member is not more than 200 mm. 3. An apparatus according to claim 1, wherein the second predetermined length of said flange portion is not less than 10 mm. 4. An apparatus according to claim 1, wherein said flange portion extends outwardly from said tubular member to form an angle of substantially 90.degree. with respect to a tube axis. 5. An apparatus according to claim 1, wherein said flange portion extends outwardly from said tubular member to form an arc with respect to a tube axis. 6. An apparatus according to claim 1, wherein said flange portion is constituted by a bent portion formed by bending said distal end portion of said tubular member outwardly therefrom with respect to a tube axis. 7. An apparatus according to claim 6, wherein 8. An apparatus according to claim 7, wherein said flange portion is formed into an annular shape by connecting adjacent ones of said bent portions with connecting members made of a magnetic shield material. 9. An apparatus according to claim 1, wherein said flange portion is constituted by an exclusive flange member made of a magnetic shield material and attached around said distal end portion of said tubular member. 10. An apparatus according to claim 9, wherein 11. An apparatus according to claim 1, wherein 12. An apparatus according to claim 1, wherein