Semiconductor wafer boat for batch processing

A vertical boat for supporting a plurality of semiconductor wafers for processing, wherein the wafers have a radius of 100 mm, 150 mm or 225 mm, the boat comprising:

• a plurality of at least three vertical support members spaced around a vertical axis and having a plurality of vertically spaced sets of horizontally aligned slots therein, one slot of each set being in each of the members on a side thereof generally facing the vertical axis;
• the boat having a front side from which wafers are loaded into the boat and a back side;
• each slot having an upwardly facing wafer support surface at the bottom thereof and having a depth measured from the vertical axis of approximately 5 mm or more larger than the radius of the wafers;
• adjacent vertical members being spaced less than 180 degrees apart around the vertical axis, at least one of the vertical members being spaced rearward of the vertical axis toward the back side of the boat, and two of the vertical support members being spaced forward of the vertical axis toward the front side of the boat such that the corresponding slots therein of each set provide horizontal clearance therebetween of at least 4 mm more than twice the radius of the wafers for insertion and removal of the wafers therebetween;
• and
• the upwardly facing wafer support surface of each slot having a recessed area thereon recessed approximately 0.5 mm below the wafer supporting surface and extending inward from a radius, measured from the vertical axis, of approximately 1 mm greater than the radius of the wafer, thereby forming an inwardly facing step approximately 1 mm from the edge of a wafer supported on the recessed areas.

A method of performing a carbon process on a plurality of semiconductor wafers, comprising:

• loading a plurality of horizontally-oriented, vertically-spaced semiconductor wafers into a corresponding plurality vertically-spaced slots in a boat for supporting the wafers in a processing chamber, the loading including:
• inserting the plurality of wafers between a pair of vertical forward support members with slots therein spaced apart by more than the diameter of the wafers with clearance on both sides of the wafer;
• then
• centering the wafers on a vertical axis of the boat;
• then
• lowering the wafers onto a recessed area in each of the slots with inwardly facing steps in said slots spaced closely from the perimeter of the wafers and confining the wafers to the recessed areas;
• then
• subjecting the wafers on the boat to a carbon process;
• then
• unloading the plurality of wafers from the boat by:
• raising the wafers from the recessed areas;
• then
• removing the plurality of wafers from a centered position on the boat, between the pair of vertical forward support members.