Semiconductor wafer stacking apparatus and method

DETAILED DESCRIPTION The invention is an apparatus and method for stacking, aligning, and mounting semiconductor wafers prior to mounting the stacked wafers for polishing the edges of the wafers.
A plurality of wafers alternating with spacers are assembled from wafer cassettes.
A plurality of wafers are loaded, from a wafer cassette, in to an integrator.
The wafers are held in the integrator spaced apart from each other, leaving sufficient space for a spacer.
A second cassette holding spacers is then placed adjacent the integrator, and the spacers moved into the integrator such that one spacer is placed between adjacent wafers.
The alternating spacers and wafers are moved out of the integrator to an alignment tower where an axial clamp holds the wafers/spacers together in axial alignment with the wafer surface perpendicular to the axis.
The wafers/spacers are removed from the alignment tower, still clamped together and placed in a polishing machine.
After the stack of wafers has finished its cycle in the edge polish apparatus, the stack is unloaded and the wafers separated from the spacers in one of two different ways.
(1) The stack of wafers/spacers is first pushed unto a separation box (de-integrator).
The wafers are next blocked from forward movement by a pinning bar, then the spacers are pushed by a series of rods into their cassette for rinsing, drying and reuse.
The stacked wafers and separation box are tilted onto a tank of water and the pinning bar retracted; the wafers are thereby allowed to fall into a waiting cassette for spin rinse, drying and further processing.
(2) The stack of wafers/spacers is pushed into a separation box.
The separation box is tilted into a tank of water such that the wafer and spacer are essentially vertical.
A pinning bar keeps the wafers from falling, but the spacers fall into a waiting spacer cassette.
Next, the spacer cassette is moved out of the way, and a wafer cassette is moved into the receiving position.
The pinning bar is extracted and the wafers fall into the cassette for further processing