| 摘要 |
Provided is a method to grind an object, capable of preventing a mark, caused by a contact terminal of a thickness measurer, on a ground surface of an object, grinding the object regardless of its kind, and also grinding the object while measuring the thickness of the object even if a protecting material is attached to the surface of the object. The grinding method, making an object as thin as a predetermined thickness by grinding the rear surface of the object with a protecting material, includes: a first grinding step of grinding the rear surface of the object up to a predetermined thickness while measuring the actual thickness of the object through only a second ultrasonic measurer based on a difference between propagation times of reflected waves from the front and rear surfaces of the object; a protecting material thickness calculating step of calculating the thickness of the protecting material from a difference between the actual thickness of the object, measured through the second ultrasonic measurer, and a total thickness calculated from a difference between an upper height position of a chuck table, measured through a first ultrasonic measurer, and an upper height position of the object, measured through the second ultrasonic measurer; and a second grinding step of calculating the thickness of the ground object from the thickness of the protecting material and the difference between the upper height position of the object, measured through the second ultrasonic measurer, and the upper height position of the chuck table, measured through the first ultrasonic measurer, after the protecting material thickness calculating step. |
