UMC90 Design Flow Getting Started

For the project, we will be using the 90nm technology from UMC as is made available to you. It can be found at /opt/cad/cadence/Designkits/UMC90. To learn this technology, and also the accompanying design flow, there is a tutorial document that can and should be used by you to become familiar with this flow. This tutorial is written by the UMC company. The tutorial will not introduce all the features and capabilities of the tools, for this you should consult the documents that come with Cadence. However, the proposed flow is exactly what we need for the project, although you can still choose between Assura and Calibre for parasitic extraction.

The tutorial is called the Foundry Design Kit for 90nm, it can be found at /opt/cad/cadence/Designkits/UMC90/designkit/FDK_User_Guide_V1_1.pdf

Before getting started, please note the following to adapt the tutorial to our situation. In particular, consider Page 6 of the FDK tutorial, 'Setting Up Your Design Environment'. Note that for notation, we will write step FDK.1 and similar for one of the steps as listed on Page 6 and 7 of the FDK document (to discriminate them from the numbered steps in this page).

1. As the first step, before any of the steps listed in Page 6, you should copy the .cdsenv file to your home directory.
   cp /opt/cad/cadence/5.1.41/lnx86/IC5.1.41/tools.lnx86/dfII/samples/.cdsenv ~/.cdsenv

2. Then you should follow steps FDK.1 and FDK.2. However, the .simrc file (step FDK.2.2) is not there. Only copy the cds.lib and display.drf files. Note that /fdkInstallPath should be replaced by /opt/cad/DesignKits/UMC090/designkit

3. Then, before doing step FDK.3, when you are in the design directory, you have to copy a .cdsinit file:
   cp /opt/cad/cadence/5.1.41/lnx86/IC5.1.41/tools.lnx86/dfII/cdsuser/.cdsinit .cdsinit

4. Continue with step FDK.3 on Page 6. It instructs to changed the cds.lib file. Do this as follows:
   INCLUDE /opt/cad/DesignKits/UMC090/designkit/cds.lib
   That is, fdkInstallPath should be replaced by /opt/cad/DesignKits/UMC090/designkit.

5. If you understand about .cshrc files, please go ahead with steps FDK.4 and FDK.5. Otherwise, before running the FDK tools, just execute the following two commands
   setenv CDS_Netlisting_Mode Analog
source /opt/cad/cadence/5.1.41/sourceme
   each time after you have logged in, immediately after you have logged in.

After performing the steps above, you can go ahead an work through the FDK tutorial. However, while doing, consider the following.

1. On Page 24, in Step 3, you should only include the library file for the transistor model that you are using. You can achieve this by first selecting all libraries and than disabling them, followed by selectively enabling only the /opt/cad/DesignKits/UMC090/designkit/Models/Spectre/L90_SP10_V051.lib.scs library.

2. At several places in the tutorial, there is the concept of number of fingers for a MOS transistor. This relates to the partitioning of a wide transistor into a couple of parallel transistors --- each finger is in fact a separate transistor, but with shared source/drain regions and the metal configured so that they are all electrically parallel. You can experiment with this feature, and see how the transistor will look. Making a wide transistor into a number of smaller transistors usually gives a more favorable layout. For the project, however, you will probably need only 1-finger transistors!