memoslw
Newbie level 5
Fellow IC designers,
I have a BGR design where I use 5 resistor instances in the circuitry. I want to interdigitate these resistors, however, It is not possible to do this automatically through Virtuoso. I have looked at MODGEN, but for a true interdigitated resistor, I need the fingers of the resistors to come one after another. More information and questions are below, any help/info would be really appreciated:
I have a BGR design where I use 5 resistor instances in the circuitry. I want to interdigitate these resistors, however, It is not possible to do this automatically through Virtuoso. I have looked at MODGEN, but for a true interdigitated resistor, I need the fingers of the resistors to come one after another. More information and questions are below, any help/info would be really appreciated:
- I have 5 resistor instances (A, B, C, D, E), each of these resistors consists of 5 poly silicon strips connected in series. When generated from the schematic of the BGR circuit, these resistors are created separately, as usual, where each of them has 5 series strips connected together through the metal layer. Because of that I have made a custom layout for an interdigitated resistor design. The pattern of this resistor layout is ABCDEABCDEABCDEABCDEABCDE, later on these strips are connected in series accordingly (A is connected in series to the next A, and so on...) through the metal layers. By this way, I have one huge resistor instance which is interdigitated, which I thought would be better for matching purposes. Does this practice make sense in terms of matching resistors?
- How can I add this custom resistor to the schematic of the BGR circuit? In the end, I have to do LVS and then the parasitic extraction, the custom resistor have no connection to the other instances in the circuit right now. Is there a way to edit connectivity so that I can pass the LVS check and then the parasitic extraction?
- As I said before, I have checked the MODGEN in Virtuoso, but it doesn't seem to really interdigitate the resistors, it rather puts them next to each other. I would like to hear your MODGEN experiences with resistors. I found it not very helpful in terms of the resistor matching, but useful for the transistor matching.