LAYOUT DESIGN:VERTICAL CONNECTION DIAGRAM

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VERTICAL CONNECTION DIAGRAM

In the majority of ASIC processes there are very straightforward rules for connectivity. An ASIC process has one poly for the gate and three to six metals. That means that we have to work with one contact type and two to five types of vias. The connectivity is easy to understand because to connect from active to metal6 we need all the possible contacts and vias.

In more complicated processes, it is advisable to generate a vertical diagram of layer connectivity so the layout designer can fully understand the connectivity scheme. Figure 3.20 shows a DRAM process that is made with four poly layers and three metal layers. In this type of process there are restrictions on layer uses and connection rules.

Layout Design-0034

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