Apparatus for inspecting the appearance of semiconductor devices

An apparatus for inspecting packaged semiconductor devices comprising:

• a turntable including at least four vacuum chucks for holding and releasing semiconductor devices, said turntable rotating about a central axis;
• means for incrementally rotating said turntable about said axis to position said vacuum chucks in first, second, third, and fourth rotational positions;
• loading means for transferring uninspected semiconductor devices from storage trays to a first conveyor means for conveying the uninspected semiconductor devices to said vacuum chucks in the first rotational position;
• said first conveyor means including a first elongated tray having a plurality of compartments, each compartment for containing a semiconductor device and means for incrementally moving said first elongated tray towards said vacuum chucks in the first rotational position;
• means for translating said vacuum chucks in the first, third, and fourth rotational positions between (i) a lowered position for engaging and releasing a semiconductor device before and after inspection, respectively, and (ii) a raised inspecting position for inspection of a semiconductor device when said vacuum chucks are in the second rotational position;
• inspection means for inspecting the exterior of a semiconductor device including imaging means for forming an image of a semiconductor device held by said vacuum chucks in the second rotational position and image analyzing means for analyzing the image formed by said imaging means and for determining whether an imaged semiconductor device is acceptable;
• second conveyor means for conveying acceptable semiconductor devices away from said vacuum chucks when in the third rotational position, said second conveyor means including a second elongated tray having a plurality of compartments, each compartment for holding a semiconductor device, and means for incrementally moving said second elongated tray away from said turntable when said vacuum chucks are in the third rotational position;
• unloading means for transferring acceptable inspected semiconductor devices from said second elongated tray to storage trays;
• discard means for receiving unacceptable semiconductor devices when said vacuum chucks are in the fourth rotational position;
• and
• control means responsive to said inspection means for controlling said means for incrementally rotating said turntable and said means for translating to release an acceptable semiconductor device from a vacuum chuck in the third rotational position and to release an unacceptable semiconductor device from a vacuum chuck in the fourth rotational position to said discard means.