[SOLVED] virtuoso layout we have M1 of different types: drw, net, gnd, ohs, different?

[chuangna]

Guys, when using virtuoso, i've noticed that we have many different types of the same layer
For example, for metal 1, we have different types such as drw, pin, and, net, etc.....
therefore, i am wondering whether or not I can get any data sheet explaining these types( I searched for a whole day and failed finding anything useful.)

 

[hamidmoallemi]

as I remember Layers with drawing purpose will show in the mask layout. you will use them to draw physical connections
Layers with pin purpose are not part of the mask layout . They indicate position of I/O pins for automatic routers. you can use them when you want to assign a net name to a metal connection , e.g. VCC or GND

 

[chuangna]

Thanks hamidmoallemi, what about other types? like M1-"net", M1-obs"

 

[ThisIsNotSam]

don't worry about those unless you are exporting some layouts to digital macros as LEF files. obs means obstruction, so the router knows it cannot go through there.

 

[dick_freebird]

"net" will be generated by extract, creating the "extracted"
cellview, used to build the netlist.

Some kits go further with sub-purposing layers (like gnd, vdd,
vdda, whatever). This supports (or can) electrical design rule
checks, "shorts" checks as a DRC based tool (like met1/gnd
must not touch met1/vdd, etc.).

"obs", I have no idea. But I'd bet that reading the design rules
docs that attend the PDK, would describe each layer-purpose
pair. Or should....