Parameterized Cell Tutorial - How to Instantiate a Pcell

If you have not created "pcell_demo" Pcell yet, please click here.

Now that you have created the "pcell_demo" Pcell, let learn how to use it in a layout design. This part tutorial will give step by step instruction of how to instantiate a Pcell in your layout. Then we will see how to adjust the parameters of a Pcell instance. At the end, we will see how a comb drive is created in just a few minutes by using this Pcell.. In a later tutorial, we will also use this Pcell to create a mesh for metal membrane designs. This tutorial assumes you have set up and started Cadence properly. This tutorial is process independent. However if you choose to skip steps, pre-created tutorial Pcells exists in hp_cds (MOSIS HP 0.5um process).

Part I. Instantiate This Pcell
Part II. Adjust Parameters
Next: Create A Mesh layout with this Pcell

Part I. Instantiate This Pcell

1. Let's start with a new "test" layout. Please refer to Layout Edit Help on how to create a new layout.
2. In layout window, click Instance icon, a Create Instance window will pop up:
   
   
   
   
3. In Create Instance window, click on Browse button:
   
   
   
4. A Library Browser - Create Instance window will pop up. Select layout view of the "pcell_demo" cell in the "demo_lib" library.
   
   
   
   Click on Close.
   
5. The Create Instance window will change to include the parameters of the Pcell.
   
   
   
   Input desired parameters:
   finger_length = 8
   fingers = 4
   step_distance = 8
   Then click on Hide button.
   Red circle indicates user input.
6. In layout window, carefully left click at x=0, y=0 to position the Pcell instance at x=0, y=0
   
   
   
7. Press SHIFT-F to see the detailed hierarchy of the layout . Then press F key to get a full view of the layout.
   
   
   

Part II. Adjust Parameters

1. Select on the instance and press Q. An Edit Instance Property window will pops up.
   
   
   
2. Click on the Parameter checkbox in Edit Instance Property window.
   
   
   
   Type in desired parameters:
   finger_length = 40
   fingers = 20
   step_distance = 8
   Then click on OK button.
   Red circle indicates user input.
3. In layout window, you will see the parameters have been adjusted!
   
   
   
   
4. You can create a comb drive by instantiating the "pcell_demo" Pcell twice and by drawing two rectangles for the comb trusses.
   
   

After you feel comfortable with this simple example, you can go to build a mesh design from this finger Pcell.

Created September 17, 2001 by Kai He at khe@ece.cmu.edu