EE 4325 / 6325 VLSI DESIGN
INTRODUCTION TO CAD TOOLS
Outline
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VLSI design flow
Basics of UNIX / Linux
CADENCE
HSPICE
– WAVEFORM VIEWER
VLSI Design Flow
DESIGN
IMPLEMENTATION & SYNTHESIS
Verilog/Vhdl simulator
Synopsys DesignVision
STANDARD CELL LIBRARY DESIGN
Cadence/synopsys
AUTOMATIC PLACE AND ROUTE
Encounter
DESIGN VERIFICATION
Hspice/NCX/PrimeTime
STANDARD CELL LIBRARY DESIGN
Design Flow for A Cell
• Create Views (by Cadence)
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Schematic View
Layout View (DRC/LVS/PEX)
Symbol View
Abstract View
• Simulation (by Synopsys Hspice)
UNIX / Linux commands I
File Commands
• ls – list contents of the directory
• ls -al – formatted listing with hidden files
• cd <dir> - change directory to dir
• cd – change to home
• pwd – show current working directory
• mkdir <dir> – create a directory dir
• rm –f <filename> – delete file
• cp file1 file2 – copy file1 to file2
• cp -r dir1 dir2 – copy dir1 to dir2; create dir2 if it doesn't exist
• mv file1 file2 – rename or move file1 to file2 if file2 is an existing directory, moves file1 into
directory file2
Process Management
• ps – display your currently active processes
• Kill %%-- Kills the current process
• kill pid – kill process id pid
• killall proc – kill all processes named proc *
• bg – lists stopped or background jobs; resume a stopped job in the background
UNIX / Linux commands II
Shortcuts
• Ctrl+C – halts the current command
• Ctrl+Z – stops the current command, resume with
• fg in the foreground or bg in the background
• Ctrl+D – log out of current session, similar to exit
• Ctrl+W – erases one word in the current line
• Ctrl+U – erases the whole line
• Ctrl+R – type to bring up a recent command
• !! - repeats the last command
• exit – log out of current session
Help for all the commands can be obtained on the terminal using
• man <command name>
Servers you can use for VLSI – Apache, Jupiter
Please go to TA’s tutorial website for learning UNIX / Linux
MOS Transistors
Side View of Transistors
• What they really look like a 130nm transistor from the IBM G5 processor:
Image Source: Apple Computer www.apple.com
TOP View of Transistors
S
D
S
D
N-well
NMOS
PMOS
Cadence – Layer Selection Window (LSW)
Active layer
Instances / Pins selectable
Visibility & selection controls for all layers
AV: All layers visible & selectable
NV: All layers invisible & unselectable
AS: All visible layers selectable
NS: All visible layers unselectable
Note: invisible layers are always unselecable
Layer list
Click with LEFT mouse button to select the layer as
the ACTIVE layer
Click with MIDDLE mouse button to switch
VISIBILITY of the layer
Click with RIGHT mouse button to switch
SELECTABILITY of the layer
IBM 130nm Design Rules
Design Rule Check (DRC) Errors
Error showing that the minimum space between two adjacent M1 layers should be
>=0/16um
Layout Versus Schematic (LVS) Errors I
Layout Versus Schematic (LVS) Errors II
Alternatively, you can go to "View->LVS Error Report (Current Cell)" to bring up the net list of errors,
and then you can select the names to highlight the mismatches on both the schematics and layout.
Pitch Size (IO Pin Spacing)
For our project design, in the cell library design, the distance between pins should be
0.48×n (n=1, 2, 3…) um.
And the distance between the GRLogic and its adjacent pin should be
0.24+0.48*n (n=0, 1, 2, 3…) um.
0.48um
Cadence Shortcuts I
Key
Function
Key
Function
Display/View/Zoom
Edit
z
Zoom in (box)
F4
Switch selection mode (Full/Partial)
Ctrl-z
Zoom in by 2
u
Undo
Shift-z
Zoom out by 2
Shift-u
Redo
f
Fit in window
m
Move
Ctrl-r
Redraw
s
Stretch
k
Create ruler
c
Copy
Shift-k
Delete all rulers
Shift-r
Rotate
del
Delete
Create
r
Create rectangle
q
Properties
p
Create path
Ctrl-a
Select all
Shift-p
Create polygon
Ctrl-d
Select none
l
Create label
Hierarchy
i
Create instance
Shift-x
Descend into cell (new window)
Ctrl-p
Create pin
x
Descend into cell (edit in place)
Cadence Shortcuts II
Please go to TA’s tutorial website for learning Cadence Tools
• Inverter layout tutorial
• Layout tips for IBM 130nm technology
• DRC, LVS and PEX(parasitic extraction)
HSPICE
TO RUN HSPICE:
1. Source
. /proj/cad/startup/profile.synopsys
2. Type:
hspice <spi_file_name.sp>
3. You can check the output log if there’s any warning or error. After it said "job
concluded", your simulation waveform result is stored in
spi_file_name.tr0
4. If there are no errors then the outputs can be viewed by waveform viewers.
5. Use Cosmoscope or waveviewer to view the waveforms by typing scope
& or wv &
HSPICE Example I
* first line must be a comment or empty line
* HSPICE is case in-sensitive and will convert all to lower case and so inv.sp == INV.sp
* Transistor model file
.include“/home/cad/kits/IBM_CMRF8SFLM013/IBM_PDK/cmrf8sf/relLM/HSPICE/models/model013.lib_inc“
.include inv.sp
* the netlist for INV gate.
.OPTIONS POST = 1
Xinv in out inv
*INV gate with input (in) output (out) (Please follow the port order in inv.sp)
.param VDD = 1.2V * Parameter definitions
vdd! vdd! gnd 1.2V * Power supplies
Vin in GND PWL (0ns VDD 4ns VDD 4.5ns 0 8ns 0 8.5n VDD ) * input voltage source
.tran 10ps 10ns
* Run the transient simulations for 10ns with a step size of 10ps
* Propagation Delay Measurements
.measure tran Tphl_out trig v(in) val='VDD/2' rise=1 + targ v(out) val='VDD/2' fall=1
.measure tran Tplh_out trig v(in) val='VDD/2' fall=1 + targ v(out) val='VDD/2' rise=1
* Average Power Measurement
.measure tran AvgPower avg p(VVdd)
.END
HSPICE Vector Input Example I
* The vector file that has the inputs in a digital format. The file name is case in-sensitive.
; VECTOR PATTERN DEFINITIONS
; Radix -- number of bits associated with each vector (e.g. 1 4 => one 1-bit and one 4-bit vectors)
; Vname -- name of each vector
; IO
-- determines inputs, outputs or bidirectional
; Tunit
-- indicates time unit for the tabular data
; Period -- Used for periodic data to define period for one vector
; Trise
-- Rise time for signals
; Tfall
-- Fall time for signals
; Vih
-- Logic "1" voltage (VDD is defined in the netlist)
; Vol
-- Logic "0" voltage
;===========================================================
; DEFINING TABULAR DATA
; Tabular data is provided in chronological order. In this example since "Period" is defined, the first
; column corresponding to "time“ is not needed. However, for non-periodic tabular data "time" is
; needed in the first column. If outputs are provided in the tabular data, then Hspice will compare the
; actual and expected outputs
HSPICE Vector Input Example II
;======================== Example ======================================
.VEC Nand2.vec
Radix 1 1
* number of bits associated with each vector
Vname NAND2_A NAND2_B
* name of each vector
IO I I
* inputs, outputs or bidirectional
Tunit ns
* time unit for the tabular data
Period 10
* period for one vector
Trise 0.1
* Rise time
Tfall 0.1
* Fall time
Vih VDD
* Logic "1" voltage
Vil 0.0
* Logic “0" voltage
* Tabular data
00
01
10
11
HSPICE Waveform Viewers
Available viewers:
• WaveView
• CosmosScope
Please go to TA’s tutorial website for using Waveform Viewers