Semiconductor device with multiple contact sizes

摘要

A semiconductor device having multiple layers uses different size contacts at different layer in order in order to simplify the manufacturing process and the depth of etching required. Contact sizes are selected based on the responsiveness of the material to the etching process. Where a deep etch is required, a larger contact is used. A shallower etch through similar material uses a smaller contact to slow the etching process. As a result, the etches can complete at about the same time. The technique can be employed to etch any number of contacts. An intermediate size contact can be used where the material to be etched results in a slower etching process. A plurality of contact sizes can be used depending on the depths of etching required and the characteristics of material to be etched, so that the etching for all the contacts completes at substantially the same time.