Patent ID: 7070479

Claim:
An arrangement for conditioning a polishing pad, which is designed to perform chemical mechanical polishing of semiconductor devices, the polishing pad being mounted on a rotatable polishing platen, the arrangement comprising: a conditioner comprising a conditioning disc, the conditioner being movable across the polishing pad; and a measurement unit for measuring the thickness of the polishing pad, the measurement unit including; at least one sensor for measuring a distance between a reference level and a surface element of the polishing pad, wherein the sensor is a laser sensor; and a control unit, connected to the at least one sensor, for calculating the thickness of the polishing pad from the distance measurement, wherein the at least one sensor comprises at least two laser sensors mounted to a support, the support also supporting the conditioning disc, wherein a first of the at least two laser sensors is mounted to the support on a first side, the first side being orientated towards a direction of movement of the conditioner, and a second of the at least two laser sensors is mounted to the support on a second side, the second side being opposite to the direction of movement.