In an embodiment, a system includes: a pad comprising a first side and a second side opposite the first side, wherein the first side is configured to receive a wafer during chemical mechanical planarization (CMP), and a platen adjacent the pad along the second side, wherein the platen comprises a suction opening that interfaces with the second side; a pump configured to produce suction at the suction opening to adhere the second side to the platen; and a sensor configured to collect sensor data characterizing a uniformity of adherence between the pad and the platen, wherein the pump is configured to produce the suction at the suction opening based on the sensor data.