| 摘要 |
PROBLEM TO BE SOLVED: To improve structural strength of a bell jar.SOLUTION: A bell jar 10 is made of quartz glass constituting a chamber 110 of a vacuum processing device 100 for applying predetermined processing to a processing object by making inside of a chamber 110 into a negative pressure. The bell jar 10 has: a bell-shaped body part 11 whose bottom end is opened; a flange part 12 formed along a bottom end of the body part 11; and a protrusion part 13 formed at a portion upper than the flange part 12 on a side face 11a of the body part 11, and extending in a circumferential direction of the body part 11. |
