Method for fabricating a die seal

摘要

The present invention provides a method of fabricating a die seal. The die seal comprises a buffer area being adjacent to a die, a buffer space being adjacent to a scribe line, and a seal ring located between the buffer area and the buffer space. The seal ring is stacked by at least one metal layer and at least one dielectric layer. A passivation layer is formed and covers entire the die seal. The method comprises forming an amorphous silicon film on a top metal layer prior to the step of forming the passivation layer, and removing the dielectric layer on the buffer space by applying the amorphous silicon film as an etch stop layer in the step of etching the passivation layer to enhance the robustness of the die seal from damage by a lateral stress when a wafer is sawed. When the dielectric layer is made of SiO2, a plasma containing CF4 and H2. can be utilized in the step of etching the passivation layer. Because the plasma has an extremely high etching selectivity ratio, the SiO2 on the buffer space can be completely removed.