Patent attributes
A test station for testing polishing heads for planarizing semiconductor wafers and other substrates has a head positioning control system which can precisely position the polishing head at one of many electronically controlled positions above the test station platform. The test station may also include a lateral carriage assembly which supports the polishing head above a base plate of the station and permits the polishing head to be moved in a gliding motion above the surface of the test station test wafer. A sensor senses when the carriage of the assembly is moved from a load position. In response, the test station controller causes a vertical actuator to lift the head mount in the vertical or Z direction. In this position, there is sufficient clearance for the polishing head being carried by the carriage to slide under the head mount and into position for mounting to the head adapter. The carriage includes a carriage plate, the top surface of which defines a generally disk segment shaped recess which is sized and shaped to receive the bottom of a polishing head of a first size, such as a polishing head adapted to hold 300 mm semiconductor wafers for polishing, for example. The test station includes an adapter plate which may be placed onto the carriage plate of the carriage instead of a polishing head. The adapter plate has a recess which is sized to receive a different sized polishing head. A wafer chuck can chuck test wafers of different sizes, such as 200 mm wafers and 300 mm wafers, for example and includes a plate which defines a first set of annular-shaped grooves in a first area which is a central disk-shaped area. A second set of annular-shaped grooves are positioned in a second area which is annular shaped and surrounds the central area. The test station has two independent vacuum lines coupled to the first and second sets of grooves respectively, which draw vacuum pressure through the grooves to draw a test wafer down and chuck the test wafer in place on the wafer chuck.
