| CPC G01B 5/28 (2013.01) [G01B 5/0007 (2013.01); H01L 21/67288 (2013.01); H01L 21/67769 (2013.01)] | 14 Claims |

|
1. A flatness measurement unit to be placed on a shelf for measuring flatness relating to degree of deviation from a state in which four predetermined points on the shelf are present on the same plane, the flatness measurement unit comprising:
a body frame; and
four contact sections dispersedly disposed on the body frame and provided so as to be in contact with the four predetermined points on the shelf, wherein
the four contact sections include two first contact sections not located diagonally and two second contact sections other than the first contact sections, and
the center of gravity of the flatness measurement unit is positioned in an area containing the two first contact sections, among four areas defined by two diagonal lines each passing through one of the two first contact sections and one of the two second contact sections that are located diagonally.
|