1. VLSI Layout using Microwind
Kishore C Acharya

2. Getting Microwind Go to the website http://www.microwind.org
Download the freeware version of the microwind in a Folder called microwind_source
Unzip the files in a Folder called microwind_layout

3. Setting Up Technology File
Launch the program microwind2.exe from the folder microwind2-7 within microwind_layout folder
From File Menu-> Select Foundry
Browse to Folder Micrrowind2-7 and open the file cmos06.rul On the Layout window at the Top left there is a ruler. The ruler should say 5 lambda and 1.5 micron

4. Creating your own rule file
If the appropriate rule file is not available, you can create your own rule file:
Using notepad open the file default.rul in microwind2-7 folder
Edit appropriate parameters
Save as a new file
Note: Oxide thickness is defined in l3tox within spice parameters

5. Suggested Directory Tree
Main Directory C or D
Microwind_source
Microwind_layout
Contains microwind2,zip
Microwind2-7
ee393_layout
Contains all layout files
And special .rul files
Contains all microwind files
Automatically built during Unzip

6. Opening and Saving Layout Files
Open: From File menu Select Open and Browse to the folder ee393_layout and open the appropriate .msk file
Save: From File Menu select Menu item Save as and save layout file in ee393_layout directory
You must setup Technology Right after Launch before any work

7. Working with Layout Notes
To draw a transistor click on the transistor symbol in the Palette window.
Select transistor type (PMOS or NMOS)
Select the units in lambda and specify width in terms of lambda
Delete: select the Gun icon and either click on each color section or draw a border around the device

8. To Do Layout
Select the appropriate trace e.g. poly, metal1, contact etc.
Draw a rectangle by dragging the mouse and the appropriate trace will be drawn as you release the mouse button

9. Design rule checker
During layout process check if the component placements such as NMOS, PMOS transistors are correct.
From the Analysis menu select the menu item Design Rule Checker
If the placements are correct Checker will report No error
If there are errors, checker will display them on the components in the placement window
Clicking the mouse in the placement window will remove the error display

10. Well Contacts
From Palette menu select contact (three bars next to transistor symbol)
Select N+ to Metal contact
Place the contact on a Metal line over the N well (if needed extend the N well over the Vdd bus
Run design rule checker

11. Substrate Contacts
From Palette menu select contact (three bars next to transistor symbol)
Select P+ to Metal contact
Place the contact on a Metal line (ground bus) next to the NMOS transistor
Run design rule checker

12. Metal to Metal Contacts
From Palette menu select contact (three bars next to transistor symbol)
Set Poly to Diff Contact selection to none
Check () appropriate metal to metal contact (e.g. Metal 1 to Metal 2)
Place the contact on the intersection of the two Metal lines
Run design rule checker

13. Working with Layout Notes Continued
Rotate & Flip: From Edit Menu select menu item Flip or Rotate -> Flip or Rotation angle
Draw a box around the object
Move: From Edit Menu select menu item Move or Stretch
Draw a box around the object and move the object by dragging the mouse
click on an edge of the object and stretch it by dragging the mouse

14. Working with Layout Notes Continued
Pan: From the tool bar use left, right top and bottom arrows for panning alternatively use the arrow keys from the keyboard
Move stepwise: From Edit Menu select menu item Move Step By Step
Draw a box around the object and move the object by clicking on the arrows that appears on the screen

15. Working with Layout Notes Continued
Delete: From the menu bar select the gun symbol (Delete Some Layout)
Method 1:Draw a box around the object to be deleted using the mouse and let go the mouse button
Method 2:Place the mouse pointer on the object to be deleted and click the right button

16. Working with Layout Notes Continued
Zoom in: From the tool bar use Zoom in icon and then click on the Layout Window
Zoom out: From the tool bar use Zoom out icon and then click on the Layout Window
On the tool bar click on the draw box icon to stop Zoom operation
To Print: From the File Menu select Menu item Print Layout

17. Obtaining parasitic values
Put the mouse on a section of the Layout (e.g. Metal lines, Gate connections etc) and click the right button of the mouse.
From the displayed menu at the mouse point select the menu item Node Properties
A new window called Navigator will be displayed
Read the parasitic values displayed in the navigator Window
If the parasitic values are not displayed click on Props Tab of the Navigator window

18. Some drawing & design rule help
Make width of all metal lines 4l
Make spacing between two adjacent metal lines 6l
When making contact between metal and polysilicon, build a 4l by 4l pad with polysilicon for connection
For layouts needing many connections use Metal 1 for Horizontal lines and Metal 2 for vertical lines

19. Changing Layout display
To BW Layout
From File Menu Select menu item Colors
From Colors submenu click on Monochrome
From Colors Submenu White or Black back ground can be selected by clicking on White background
To Color Layout
From the Colors submenu click on Color

20. Naming Nodes and Assigning Parameters
Select a node by double clicking on it
Right click and select Text Properties
Type name of the (e.g. In, Vdd, Out etc.) node in the Label name box
Select node type by clicking on the button
Enter appropriate parameters
For observation in simulation click “not in simulation”
Observable variable are shown in italics
Click on Assign button
Click on Move icon and move name into the node by clicking on it

21. Assigning Virtual Components
From the Edit menu select menu item Virtual RLC
Click on the R or L or C

22. Creating SPICE Netlist
From File menu select menu item Convert Info
Select SPICE netlist

23. About SPICE in Microwind
SPICE Model files are located in rule file
Supported Simulation Type
Frequency Sweep Analysis (Frequency vs. time)
DC Analysis (Static Voltage vs. Voltage
Transient Analysis (Voltage vs. time & Voltage,Current vs. time)
Model Selection (Level 1, Level 3& BSIM)

24. Running Simulation
If default Vdd is not correct Set default voltage to desired voltage in rule file
To find the variable in rule file search for “vdd”
Set Vdd = 5.0 for I/O & Vddh = 5.0 or 3.3 for core logic
Select Run Simulation from Simulate menu
Select Simulation type from sub menu
Setup simulation parameter in simulation dialog box that appears

25. Model & Parameter Selection
Default model is level 3
To use different model from simulate menu select using model then model type (Level 1 or BSIM) from submenu
Simulation parameters (Model, voltage range, temperature etc.)can be setup by Selecting Simulation parameter menu item from Simulation Menu

26. Simulation Parameter Setup
For Transient Analysis (Voltage vs. time or Voltage, Current vs. time)
Set to desired duration by clicking into the “Time Scale” dialog item (center right)
For DC Analysis (Static Voltage vs. Voltage
Set to desired voltage range by clicking into the “X Scale” dialog item (center right)
Simulation could be repeated by clicking into “Reset” or “more” button

27. Getting Microwind2 Go to the website http://www.microwind.org
Click on the Hyperlink (Location: Top right)
New: A book on CMOS design by J. Uyemura based on Microwind
Click on the hyperlink (Location: Below the description of the book)
Microwind 2.7 (lite version)
Download the file in a Folder called microwind_source
Unzip the files in a Folder called microwind_layout