This page will discuss the Cadence Technology File and how to set the GDSII Layer Number and Data Type Number to each one of the layers.

The Cadence Interface allows the user to define the layer mapping in three ways:

The required number of stream layers and data types will be generated without any other input.

The stream settings from the attached technology file will be used.

This mode allows the user to specify a stream layer map file to use.

We recommend to use Automatic Mode. In this mode, all visible layers will be plotted whether they are defined in the Tech. File or not.

If you want to use the Technology File, make sure all layer names are assigned to a GDSII layer and Data Type Number. Failing to do this will cause the layer not to be plotted.

Before changing the Tech. File, you want to make sure it is ok with the other designers. You also want to make sure you have file permission to make such changes. If so, go ahead and follow the instructions below.

Load your layout and then go to Technology File pulldown menu and select Edit Layer. A screen will open that looks like the picture above. This is the called the "Layer Purpose Pair Editor" and next to it is your library name. You will see all your layer names and you should click on the layer you want to set, and then click on the EDIT button.

To check if a layer is set, Click on the layer of your choice and then press the Edit button. The "Edit Layer Purpose Pair" menu will open with the information on the layer you clicked.

At the bottom of the menu, notice the following options:

Stream Layer Number - Usually a number between 1 and 256. It must be unique - two layers cannot go to same number. We also don't recommend assigning a layer to 0.

Hit OK when you are done.

You will be back in the previous menu (Layer Purpose Pair Editor) where other layers can be set in the design in a similar fashion. When done, hit OK to save the settings.

Now the user is ready to use the Cadence plotting interface in the Technology mode.

Technology File Dump

To make sure all the layers are assigned correctly you can do the following: Go to Technology File pulldown menu and Click on Dump Technology File. Pick the correct Technology Library Name you just modified. Select only the Layer Definition Option. Set an output file name (ASCII Technology File) as layer.txt for example and hit OK. You should see now a text file with all your layer definitions. Make sure each layer name has a valid layer:data_type number..