VLSI Layout using Microwind

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26 Νοε 2013 (πριν από 3 χρόνια και 10 μήνες)

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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

Microwind2
-
7

ee393_layout

Contains all microwind files

Automatically built during Unzip

Contains all layout files

And special .rul files

Contains microwind2,zip

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 4
l


Make spacing between two adjacent metal lines 6
l


When making contact between metal and
polysilicon, build a 4
l

by 4
l

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 File Menu Select menu item Colors


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