SENSOR ARRANGEMENTS FOR WAFER CENTER FINDING
A number of wafer center finding methods and systems are disclosed herein that improve upon existing techniques used in semiconductor manufacturing.
1 . A device for handling a wafer comprising:
an interior accessible through a plurality of entrances; and
a plurality of sensors consisting of two sensors for each one of the plurality of entrances, each sensor capable of detecting a presence of a wafer at a predetermined location within the interior, wherein the plurality of sensors are arranged so that at least two of the plurality of sensors detect the wafer for any position of the wafer entirely within the interior.
2 . The device of claim 1 wherein the plurality of entrances includes four entrances.
3 . The device of claim 1 wherein the plurality of entrances includes seven entrances.
4 . The device of claim 1 wherein the plurality of entrances includes eight entrances.
5 . The device of claim 1 wherein the plurality of sensors includes optical sensors.
6 . The device of claim 5 wherein the plurality of sensors includes at least one light emitting diode.
7 . The device of claim 1 further comprising a robotic arm having a center axis within the interior, the robotic arm including an end effector for handling wafers.
8 . A device for handling a wafer comprising:
an interior accessible through a plurality of entrances; and
a plurality of sensors consisting of two sensors for each one of the plurality of entrances, each sensor capable of detecting a presence of a wafer at a predetermined location within the interior, wherein the plurality of sensors are arranged so that a first pair of sensors detect a wafer entering linearly through each one of the plurality of entrances and a second pair of sensors are positioned substantially immediately outside the maximum diameter of the wafer entering linearly through each one of the plurality of entrances, and wherein each one of the plurality of entrances shares one of the first pair of sensors and the second pair of sensors with each neighboring one of the plurality of entrances.
9 . The device of claim 8 wherein the plurality of entrances includes four entrances.
10 . The device of claim 8 wherein the plurality of entrances includes seven entrances.
11 . The device of claim 8 wherein the plurality of entrances includes eight entrances.
12 . The device of claim 8 wherein the plurality of sensors includes optical sensors.
13 . The device of claim 12 wherein the plurality of sensors includes at least one light emitting diode.
14 . The device of claim 8 further comprising a robotic arm having a center axis within the interior, the robotic arm including an end effector for handling wafers.
15 . A device for handling a wafer comprising:
an interior accessible through four entrances; and
eight sensors, each capable of detecting a presence of a wafer at a predetermined location within the interior, the sensors arranged into two square arrays centered about a center of the interior, sized such that a first one of the square arrays is smaller than a second one of the square arrays and oriented so that a group of four of the sensors at opposing vertices of the two square arrays are collinear.
16 . The device of claim 15 wherein the eight sensors include optical sensors.
17 . The device of claim 16 wherein the eight sensors include at least one light emitting diode.
18 . The device of claim 15 further comprising a robotic arm having a center axis within the interior, the robotic arm including an end effector for handling wafers.
19 . The device of claim 15 wherein at least one of the four entrances is coupled to a process module.
20 . The device of claim 15 wherein at least one of the four entrances is coupled to a load lock.