AllenD
Member level 5
Hi Team
I have 2 rookie level questions about power mesh and ground mesh.
1. According to online resources, I found that a lot of people use M1 as gnd and M2 as vdd. Is this choice have any benefit over M1 as vdd and M2 as gnd?
2. My pdk have 9 metal layers with M8,M9 as ultra thick metal layers. And if I choose M1 as vdd, M2 as gnd and up to M4 to layout the interconnection within local cells. And M6-M7 to layout the interconnection on the top level. I learned that all the even/odd number layers are supposed to connect to the same power net(in my case, M1/3/5/7/9 as vdd and M2/4/6/8 as gnd). But the problem I am facing is that my M6 are consist of only 1 metal trace and a HUGE ground mash because there is not much to connect there. Is this sounds right? If it is mornal, what is the "metal filler" tool, which is to fill the empty space on chip with metal traces to meet up with density requirement, used for?
Thanks very much!
Allen
I have 2 rookie level questions about power mesh and ground mesh.
1. According to online resources, I found that a lot of people use M1 as gnd and M2 as vdd. Is this choice have any benefit over M1 as vdd and M2 as gnd?
2. My pdk have 9 metal layers with M8,M9 as ultra thick metal layers. And if I choose M1 as vdd, M2 as gnd and up to M4 to layout the interconnection within local cells. And M6-M7 to layout the interconnection on the top level. I learned that all the even/odd number layers are supposed to connect to the same power net(in my case, M1/3/5/7/9 as vdd and M2/4/6/8 as gnd). But the problem I am facing is that my M6 are consist of only 1 metal trace and a HUGE ground mash because there is not much to connect there. Is this sounds right? If it is mornal, what is the "metal filler" tool, which is to fill the empty space on chip with metal traces to meet up with density requirement, used for?
Thanks very much!
Allen