Patent ID: 7905030

Claim:
A linearity measuring apparatus for a wafer orientation flat, comprising: a base in which a plurality of straight tracks are formed in a first direction; a platform which is configured so as to be movable in said first direction by being engaged with said plurality of straight tracks via engagement means, and is further provided with a top surface formed so as to be flat to mount a wafer having an orientation flat; a block which is installed on said base with a predetermined first clearance L being provided between said block and a nearest one of said plurality of straight tracks in a second direction perpendicular to said first direction, and has a flat face against which the orientation flat of said wafer mounted on said platform abuts and which is parallel with said first direction; wafer fixing means provided in said platform to fix said wafer in a state in which said wafer is mounted on said platform; and a measurement device which is installed on said base with a predetermined second clearance M being provided with said block in said first direction, and has a probe that is opposed to said plurality of straight tracks and is capable of being displaced in said second direction, wherein when a clearance between a tip end of said probe and the nearest one of said plurality of straight tracks is taken as N, the following equation (1) is satisfied: 0 μm<L−N≦100 μm.