In this week's discussion, let's take a look at a
cornerstone of every good substrate design: plane shapes and voiding. In
particular, what do you do if you need to void around an object on one or more
layers of the object itself, whether a cline, via, bond finger, or pin, does NOT
There are many reasons for needing to do this. You may want
to ensure that a high-speed signal has no interference from nearby power nets,
or you might want to reserve space in that shape for future routing. Whatever
your reason, do not fear -- the Cadence IC Package design tools have you
The "void adjacent layer shapes" tool provides you extensive
control for generating manual voids around objects of all kinds in shapes on any
layers that you choose. If you've ever wondered how to efficiently accomplish
this without writing your own SKILL code or worrying about a lot of
intermediate steps, read on to learn more about this exciting tool!
Creating Voids in Adjacent Plane Shapes
We'll be using an early adopter feature in today's discussion,
so the first thing you need to do is to enable the command. In your User
Preferences window, navigate to the IC_Packaging -> Early Adopter folder and
enable the "icp_void_object_beta" variable. Take a minute to read the description
for the environment variable for even more ideas on times when this tool might
help you solve a problem.
You have now enabled the "void adjacent layer shapes"
command, so go ahead and run it from the command line. This will reconfigure
your options tab as shown in the image below:
As you select items in the canvas
that you want to void, you'll see the layer(s) that they exist on highlighted in
green in the table. This makes it easy to tell what layers you're working with
(and also verify you didn't select something else by mistake - hey, it happens
to all of us!).
Finally, set the layers of the
shapes you want to update with voids, and set the clearances. You can enter a
different clearance for each layer, and they can be positive (larger than the
objects to clear) or negative (smaller than the objects), depending on your
When complete, just press
the create voids button. It's a simple as that. You'll get a notification
regarding just what the tool did, and you can continue processing other objects
until your planes have all the custom voids that you want. Is it really that
simple? It sure is!
How Does the Adjacent Layer Voiding Tool Fill a Void in Your Flow?
Do you use this tool in your flows today? Or, if you're just
learning about it for the first time, do you see it simplifying part of your
flow that used to take significant time and effort, with potential for errors
due to the manual aspects of creating the voids?
Whatever the reason, if the adjacent layer voiding tool fills
a void (while itself creating voids) for you, let your Cadence customer support
representative know. We use your feedback to determine what early adopter
features to incorporate into the base product command set and menus in upcoming
releases. Ideas for improving this or any other part of the tool are always
welcome. Our tools get better with the feedback you, the designers, provide.
Help us make your flow better today, and save time on your substrate design