Patent ID: 8901492

Claim:
A method comprising: directing an electron beam toward a sidewall of a three-dimensional region of a semiconductor device with a tilting angle and a first azimuth angle; detecting a first projection distance of the sidewall through a detector placed over the semiconductor device; directing the electron beam toward the sidewall of the three-dimensional region of the semiconductor device with the tilting angle and a second azimuth angle; detecting a second projection distance of the sidewall through the detector placed over the semiconductor device; calculating a height of the three-dimensional region using a first function, wherein the first function includes the first tilting angle, the first azimuth angle, the second azimuth angle and the projection distance of the sidewall; and calculating a sidewall edge of the three-dimensional region using a second function, wherein the second function includes the first azimuth angle, the second azimuth angle and the projection distance of the sidewall.