Patent ID: 7424143

Claim:
A method for determining working positions for a device transfer apparatus in a semiconductor test handler, wherein an image input unit is mounted on the device transfer apparatus, the method comprising: moving the device transfer apparatus in horizontal and vertical directions over a first tray configured to hold a plurality of semiconductors and capturing images of the first tray with the image input unit; determining a configuration of the first tray by analyzing the images captured by the image input unit; moving the device transfer apparatus over a second tray and capturing an image of a first semiconductor holding position on the second tray; and determining working positions for the device transfer apparatus based on a position of a vertex of the first tray relative to a position of at least one semiconductor holding position on the first tray, and using the images of the first tray and the image of the first semiconductor holding position on the second tray to determine working positions for the device transfer apparatus for both the first and second trays.