Automatic wafer lapping apparatus

An automatic wafer lapping apparatus having:

• a lapping assembly consisting mainly of
• an upper lapping plate,
• a lower lapping plate,
• a sun gear provided horizontally at the center of the lower lapping plate, and
• an internal gear provided horizontally along the circumference of the lower lapping plate;
• a plurality of wafer carriers which are planetary gears adapted to mesh with said sun gear and said internal gear simultaneously;
• a pair of loader assemblies each consisting mainly of
• a wafer storage to store wafers,
• a wafer picker and setter means for picking the wafers from the wafer storage and setting them in said wafer carriers, and
• a wafer carrier setter means for setting the wafer carriers at proper positions in said lapping assembly;
• and
• an unloader assembly consisting mainly of
• a wafer recovery subassembly for recovering the wafers, and
• a wafer carrier picker means for picking wafer carriers from said lapping assembly and discarding them into said wafer recover subassembly;
• wherein
• each of said loader assemblies further comprises a turntable stage where said wafer carriers are piled up by said wafer carrier setter means and loaded with wafers by said wafer picker and setter means, said turntable stage having a vertical central shaft and a pin on which said wafer carriers are spitted;
• and
• the teeth of said sun gear and the internal gear of said lapping assembly are bevelled at their upper portions in a manner such that the upper end of each tooth is tapered and converges into a linear ridge.