First contact with Cadence icfb Schematics & Layout First contact with Cadence icfb
Pre-Steps for windows user: 1. Get an account on the Cadence server. 2. Login into the server with ssh. ssh 192.168.1.2 3. Start the VNC server for yourself. vncserver –depth 24 –geometry 1024x768 Set a your vncserver password. Remember your password and port number 4. Run VNC viewer Server: 192.168.1.2:5901 (w/ your port)
Pre-Steps for windows user: You need to re-do step 2 & 3 only after you killed the vncserver Or, a reboot of the server. If you are in a network outside our lab, please contact us to get the server ip and port.
Pre-Steps for Linux & Mac user: 1. Get an account on the Cadence server. 2. Login into the server with ssh in any GUI. ssh -X 192.168.1.2 You are ready to configure and run Cadence.
First contact Make a directory where you want to begin and save your design. mkdir mydesign Change to the directory. cd mydesign Run cadence csh source (something?) virtuoso & (virtuoso -64 if you want to run 64bit version) Read and close the “What’s new” window. Ready to work?
First contact: Ready to work? For design safety: You may want to mount a net drive as your design folder Configure the PDK. The PDK has been install on the server You need configure your environment to invoke it.
Configure / invoke the PDK Copy and rename cdsinit to your home folder mv cdsinit .cdsinit Copy cshrc_wrkDir and cds.lib to your design folder cd to your design folder and run csh source cshrc_wrkDir virtuoso & You may need to update cshrc_wrkDir if you change a PDK.
This log window is useful. You will know when to read it carefully. Tools->Library Manager… is another important window. We face to it almost everyday. You can manage (create / add/ remove) your library in this window. Try to know more about it. Now, this is a default library list.
Tools & Software for windows user Putty.exe -- ssh tools. vnc-4_1_3-x86_win32_viewer.exe -- vncviewer X-windows directly on your windows desktop. In PuTTY: Configuration->Connection->SSH-> X11->Check Enable X11 forwarding Install Xming-6-9-0-31-setup.exe, Xming-mesa-6-9-0-31- setup.exe, Xming-fonts-7-5-0-34-setup.exe Start Xming Start icfb from your ssh command line. WinSCP A file transfer between your PC and system server
To our business – schematic and layout
Design Flow
Create your library In Library manager: File->New->Library Name->OK Technology File for New … ->Attach to an existing techfile->OK Attach Design Library to Technology File smic13mmrf_1233->OK
Create your cell (1) In Library manager: Select “mystudy” File->New->Cell View Name -> OK In Virtuoso?Schematic Editing: mystudy… Creat->Instance…(i) Add Instance: Browse Library: smic13mmrf_1233, Cell: n12, View:symbol->Close
Create your cell (2) Adjust parameters as needed. Hide-> Left click to place the component ESC key to finish the placement. Then, add a p12. Add->Pin… p A: input Y: output vcc, gnd: inputOutput
Create your cell (3) Add->Wire (narrow) w Save(the left check icon) Click and connect the components. Save(the left check icon) The warnings are highlighted. Modify and save again. (No 4 wires junction, please)
Create a symbol for a cell view In Schematic Editing window, Design->Create Cellview->From Cellview OK Symbol Generation Options Adjust the pin location In symbol Editing: Change the shape with Add->Shape Save
ACHTUNG!!!!WARNING!!! Please note that usually according to normal design flow you would move onto to schematic simulation to verify that your design is correct( i.e.. Transistor sizing etc). However, in an effort to get the student more familiar with the tools we will continue straight to layout.
Create your layout (1) In Library Manger window, File->New->Library->Cell View… Tools: layout OK LSW window show the layer and colors In Layout Editing windows: Creat->Instance i Browse and fine layout of n12 and p12
Create your layout (2) Press “shift+f” to switch to the detail view Press “ctrl+f” to switch back Click a component to select it. Then press “q” to edit properties.
Create your layout (3) In Edit Instance Properties windows, In LSW Parameter->Bodytie Type: Integrated ->Left Tap OK In LSW Select GT drw In Layout Editing: Create Path p to connect poly. Then, connect Y w/ MET1 drw.
Create your layout (4) Add pin labels for each pin. pin labels must in metal tex layers for smic130 LSW->M1TXT drw In Layout Editing: Create Label l (lower-case L) Place on metal Then, Y, vcc, gnd
Design Rules Checks (DRC) In Layout Editing: Calibre->Run DRC Calibre Interactive -DRC Cancel the “Load Runset File” Rules->Calibre-DRC Rules File->… /eda/smic13mmrf_1233….v2.6/Calibr/DRC/SmicDR19…1215 33.drc Rules->Calibre-DRC Run Directory->… /home/ftliang/mydesign/drc Run DRC Only Metal Density check can be failed during the components design.
Layout Versus Schematic (LVS) In Layout Editing: Calibre->Run LVS Calibre Interactive –LVS Cancel Rules->Calibre-LVS Rules File->… /eda/smic13mmrf….v2.6/Calibre/LVS/SmicSPM7…V2.6_ 2P.lvs_XRC Rules->Calibre-DRC Run Directory->… /home/ftliang/mydesign/lvs Inputs->Netlist->Check Export from schematic …
Thanks & Please re-try some yourself.
DC simulation of a single transistor Schematic simulation DC simulation of a single transistor
Clarifications: nMOS vs pMOS nMOS with p-substrate, pMOS w/ n-well or n-substrate
Clarifications: nMOS vs. pMOS Current arrow also on the source, and current direction decides the type of MOS Be aware of the difference between VDS and VSD
Outlines What is a IV curve of a nMOS or pMOS? Simulation test bench
What is a IV curve?
Simulation test bench 1 Start virtuoso & New cell view (schematic) Add nMOS. Add gnd, vdc x2 from analogLib Connect them
Simulation test bench 2 Change parameters of V0, V1 with key q V0 V1 DC voltage: Vds V1 DC voltage: Vgs Check and Save
Simulation Settings 1 In Virtuoso Schematic window In ADE window Tools->Analog Environment (ADE) In ADE window Setup->Model Libraries & Temperature (at least) Variables->Copy From Cellview Edit->Vgs=0, Vds=3.3 Analyses->Choose
DC Simulation Settings Choosing Analyses dc Component Parameter Select Component->V0->vdc->OK Sweep Range->Start-Stop->0~1.2 OK ADE Outputs->To Be Plotted->Pick up the drain of nMOD
Setting Vgs via Parametric Analysis ADE->Tools->Parametric Analysis… Sweep->Parametric Set Variable Name: Vgs Value List: 0.5 1 1.5 2 2.5 3 3.3 Check Select Analysis->Start Nothing output? You should “Netlist and run” first.
You should know How to plot schematic How to plot simulation graph output How to save simulation setting How to adjust the graphs. How to measure something on graphs. How to calculate values in ADE and calculator.
Now swith Vgs and Vds dc->V1 (Vgs) Sweep->Vds
Try pMOS yourselves
Thanks & Please re-try some yourself.
Post-layout simulation Transient simulations of a invertor Pre- and Post-layout
Outlines CMOS fabrication Invertor Transient simulations Schematic Layout Transient simulations Pre-layout simulation PEX, parameter extraction Post-layout simulation Post-layout simulation -- F.Liang @USTC, 2013
CMOS fabrication Post-layout simulation -- F.Liang @USTC, 2013
Invertor You should have your schematic and layout from Lab 1. If you didn’t, you are fine to drop this course. No matter your layout is good or not, it should pass the DRC and LVS. Post-layout simulation -- F.Liang @USTC, 2013
Transient simulations Test bench The configuration of vpulse Why I used three invertors? ADE Variables->Copy FromCellview Analyses->Choose->tran->stop time ->conservative (What is the difference?) Output->To Be Plotted Netlist and Run Post-layout simulation -- F.Liang @USTC, 2013
PEX, parameter extraction Layout->Calibre->Run PEX Ruels:/eda/smic13mmrf….v2.6/Calibre/LVS/SmicS PM7…V2.6_2P.lvs_XRC Inputs: Netlist->Export from schematic viewer Outputs: Netlist->Format:CALIBREVIEW, Use Names From: SCHEMATIC Run PEX (You may get errors, let’s talk.) Calibre View Setup window pop up. Reset Properties: m=1 ng=1 mult=1 OK Map calibre device Post-layout simulation -- F.Liang @USTC, 2013
Post-layout simulation In your test bench cell File->New->Cell View->Type: config. Configuration View:Schematic Use Template… spectre right-click on “inverter” ->Set Cell View->calibre Save and Close Re-open config View ADE Post-layout simulation -- F.Liang @USTC, 2013
Thanks & Please re-try some yourself.
Run group of simulations in command line. Ocean scripts & misc. Run group of simulations in command line.
Outlines Misc. Ocean script Structure of your design folders cds.lib Copy or backup your real design Ocean script What is ? Where to begin with? Customisation Ocean scripts -- F.Liang @USTC, 2013
Structure of your design folders Ocean scripts -- F.Liang @USTC, 2013
cds.lib -- 行注释符 INCLUDE /pdk/chrt35/cds.lib DEFINE mystudy /home/ftliang/mydesign/mystudy In /pdk/chrt35/cds.lib $CDSHOME/share/cdssetup/dfII/cds.lib DEFINE chrt35dg_SiGe ./chrt35dg_SiGe Ocean scripts -- F.Liang @USTC, 2013
Copy or backup your real design Backup: archive all your design folder. For whole project backup, you may also backup the related pdk library. Restore: Modify the cds.lib DEFINE line In virtuoso, when you make a copy, it is usually not a full backup. Especially, it is a top level schematic or layout. Ocean scripts -- F.Liang @USTC, 2013
Ocean scripts ADE->Session->Save Ocean Script… Edit the script as necessary. In command line ocean load “xxx.ocn” Ocean scripts -- F.Liang @USTC, 2013
Thanks & Please re-try some yourself.