Hints, Tips and Solutions

Volume 11, Number 6, June 2000

Q: To simplify netlist extraction, I specify one kind of diffusion resistors in my layout by means of a special resistor definition layer. To my surprise, the extracted value for one such resistor always exactly twice the value I expected, no matter how I stretch this resistor. Other resistors (of the same type) are extracted by Maverick exactly as expected. Moreover, in my previous version of technology which defined diffusion resistors by means of intricate DRC operations all values were good.

A: The most probable reason is that you have duplicated shapes exactly overlapping each other, so that you do not see the duplication. Such shapes might result from erroneous copying. However quite often they are produced by overlapped cell instances.