1. Field of the Invention
The invention relates in general to an apparatus and a method of wafer dicing and more particularly to an apparatus and a method having a roller for separating dies.
2. Description of the Related Art
Referring to FIG. 1, a schematic view of a double-layered wafer is shown. The double-layered wafer 100 is assembled by a silicon substrate and a glass substrate. The backside 102a of the silicon substrate 102 and the upper surface 104a of the glass substrate 104 separately have several first cutting lines 112 and the second cutting lines 114. The conventional separating method of the double-layered wafer 100 is to apply a force by an operator on the first cutting line 112 of the silicon substrate 102 and the second cutting line 114 of the glass substrate 104 to break the double-layered wafer and to separate it into several double-layered dies. The strength and the direction of the force applied by the operator is hard to control; therefore the edge of the separated double-layered wafer appears to be uneven and that affects the electrical characteristic of the dies applied on components. If the area having pads on the double-layered wafer is damaged during the conventional separating process, then the damaged dies will be discarded for the dies not operating normally. The yield rate of separated double-layered dies is only 60%˜70% according to said conventional method, and the qualities of the separated dies remains unstable. Therefore it is an important issue that how to separate the wafers into dies completely and effectively.