US Patent 7292330 Wafer inspection with a customized reflective optical channel component

A method is described that adjusts the position of a item and sets a tilt angle for each of a plurality of micro-mirrors of a digital micro-mirror device. The setting of the tilt angles is to establish a filter within the optical channel of an inspection tool that inspects the item. The filter is to reduce noise received at an optical detection device. The tilt angle settings are a function of the position. The method also includes comparing information from the optical detection device that describes an inspected region of the item's surface against an expected version of the information.