Patent ID: 8662956

Claim:
A conditioner of a chemical mechanical polishing apparatus for polishing a substrate over a platen pad that rotates, the conditioner comprising: a disk holder securing a conditioning disk that finely cuts a surface of the platen pad; a piston rod delivering a normal force to the disk holder; a housing covering at least a portion of the piston rod; a load sensor installed to receive the normal force that the piston rod delivers and measuring the normal force; a shaft upwardly spaced from the piston rod; and a cylinder surrounding the shaft and the piston rod such that a pneumatic pressure chamber is formed between the shaft and the piston rod, rotating together with the shaft and the piston rod, and having a step at an outer circumferential surface thereof, the step delivering a force to the load sensor in an upper direction, wherein the load sensor is installed to be supported by the housing, and a reaction force of the normal force delivered to the cylinder through the step of the cylinder is delivered to the load sensor.