Conditioner of chemical mechanical polishing apparatus

1. 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.

2. The conditioner of claim 1 , wherein the piston rod is located on the same axis as a center of rotation of the conditioning disk.

3. The conditioner of claim 2 , wherein the load sensor is interposed between the piston rod and the disk holder.

4. The conditioner of claim 1 , wherein the load sensor is disposed at a side of an outer circumference of the cylinder, and a bearing is installed therebetween to allow a relative rotational displacement.

5. The conditioner of claim 4 , wherein delivering of the normal force to the load sensor by the step comprises delivering a shearing force via the bearing.

6. The conditioner of claim 1 , wherein the load sensor measures the normal force from a strain caused by receiving the normal force.

7. The conditioner of claim 6 , wherein the load sensor comprises a load cell.

8. The conditioner of claim 6 , wherein the load sensor comprises a strain gauge having an electric resistance varying according to the strain to measure the normal force using the strain gauge.

9. The conditioner of claim 6 , further comprising a controller for controlling the normal force applied by the piston rod to reach a predetermined value if there is a difference between a value of the normal force measured by the load sensor and the predetermined value.

10. 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; and

a load sensor installed to receive the normal force that the piston rod delivers and measuring the normal force,

wherein the load sensor is divided into two or more segments such that the segments measure normal forces around the piston rod, respectively, the two or more segments of the load sensor measure a component of the normal forces in a state where said segments do not rotate.

11. The conditioner of claim 10 , wherein the conditioner further comprises:

a controller for controlling the normal forces delivered by the piston rod, the piston rod formed into a plurality of segments, wherein if there is a deviation among the normal forces measured by the segments of the load sensor, the controller controls the deviation of the normal forces to become smaller than a predetermined value.