Device for the separation of substrates from a stack
A device for separation of damp silicon wafers from a wafer stack, whereby the damp wafers may be removed individually from the stack, transferred to a subsequent conveyor device and the damp thin fragile wafers held in the stack can be rapidly separated and isolated even in large format. The device comprises separation rollers on which the wafer stack may be placed. On rotation of the separation rollers, the lowest wafer is displaced under a doctor strip through a wafer-thin gap between the roller plane and doctor strip and withdrawn from the wafer stack by elastic pressure by a pair of superimposed delivery rollers driven at the same speed.
1. A device for separating moist silicon wafers from a wafer stack, the moist wafers being individually removable from the wafer stack, comprising:
separating rollers on which the wafer stack is placed;
a strip-off bar, which defines a gap with said separating rollers, said gap having a thickness slightly more than the thickness of a moist silicon wafer;
a plunger which engages the wafer stack; and
a pair of extraction rollers, wherein:
said plunger presses against the wafer stack;
the wafer stack is placed on said separating rollers and is subject to the pressing of said plunger, such that the lowermost moist silicon wafer can be pushed underneath said strip-off bar through said gap by the rotation of said separating rollers and can be pulled out of the wafer stack by the elastic pressure from said pair of extraction rollers aligned vertically with respect to each other and driven at the same number of revolutions as said separating rollers; and
said extraction rollers are provided with rectangular grooves between rectangular strips,
a conveying device constituted by one or several conveying elements; and
said conveying elements adjoin said separating rollers and have a higher conveying speed than said separating rollers.
2. The device in accordance with claim 1 , wherein:
said grooves and strips between roller are respectively offset from each other by one division.
3. The device in accordance with claim 1 , wherein:
said grooves and strips of adjoining rollers mesh with each other.
4. The device in accordance with claim 1 , wherein:
the pressure force of said plunger can be regulated in such a way that the sum of the weight of the stack and the pressure force is kept constant with the decrease of the height of the stack.