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Introduction to Cadence. 講員:張祐齊 日期: 2002.02.27 原講員:魏睿民 1999.10.08. Outline. Setup the environment Starting Cadence Using layout editor Extract layout to spice Using Timemill. Environment Setup. Making a directory for using cadence, such as cad.

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introduction to cadence

Introduction to Cadence



原講員:魏睿民 1999.10.08

  • Setup the environment
  • Starting Cadence
  • Using layout editor
  • Extract layout to spice
  • Using Timemill
environment setup
Environment Setup
  • Making a directory for using cadence, such as cad.
  • Specify cds.lib in your working directory.
    • The easier way is copy mine to your directory like this, cp~r89052/cad/cds.lib your_directory
  • Type icfb& to running cadence in background.
def of some files
Def. Of Some Files
  • Technology file ( ): specifies all the tech.-dependent parameters associated with that particular library.
  • divaDRC.rul, divaEXT.rul, divaLVS.rul are design rules for DIVA tools. They provide on-line rule-check in layout editor.
  • display.drf is a file containing layer display information.
  • cds.lib is a file containing library definition.
  • .cdsinit skill format, pre-define the bindkeys, skill search path, text editor.
  • .simrc skill format, set simulation and netlisting environment variable
create a new library
Create a New Library

File => New =>Library

Your library name

Choose this

Tech. file

create a new library1
Create a New Library
  • After creating a new library directory,we still need to copy some files below in the library directory:

divaDRC.rul divaLVS.rul

divaEXT.rul divaERC.rul


create a new cell
Create a New Cell

File=> New => Cell

Your library name

Specify your cell name

Choose Virtuso for layout view,

Schematic for schematic view

open layout editor
Open Layout Editor

File =>

Open …

Choose Library

Choose Cell

Choose Layout view

layout editor
Layout Editor

Present point Relative point present command

LSW Bar click middle button

physical layout techniques
Physical Layout Techniques
  • Once a circuit design is complete, it becomes necessary to provide an area-efficient layout of the circuit to generate the masks necessary for fabrication.
  • We must define the following: ”NWELL”, “PWELL”, “THIN”, “GPOLY”, “CONT”, “METAL1”, “METAL2”, “METAL3”, “VIA1”, “VIA2”, “NPIMP”, “PPIMP” in the layout database for 0.35μm TSMC process of CIC.
physical layout techniques2
Physical Layout Techniques
  • The n+ diffusion can be defined by “NPIMP” and “THIN”. With poly across, a NMOS is formed.
  • The p+ diffusion can be defined by “PPIMP” and “THIN”. With poly across, a PMOS is formed. Also PMOS is formed on “NWELL”.
  • Conductor: Poly and metals. They are in different layer and disconnected unless through “CONT” or “VIA”. “CONT” is for poly and metal1. “VIA” is used between 2 metals.
  • There is also “THIN” at “vdd!” And “gnd!”, “CONT” is required to connect “THIN” and “Metal1”. Once the “THIN” exist, there is PPIMP or NPIMP.
  • After finish drawing, do not forget to place pins on inputs and outputs.
useful hotkeys
Useful Hotkeys
  • Some useful hotkeys:
    • r: draw rectangular block
    • z/Z: room in and room out
    • k/K: ruler on/off
    • s:stretch
    • c: copy
  • m: move
  • u: undo
  • Del: delete
  • q:query
  • p: create path

(1)請用CADENCE畫出transmission-gate full adder的Layout。

(2)此Layout必須通過ON-LINE DRC check

(3) Due on March 13

getting extracted view
Getting Extracted View

Select Cparasitics

Open the extracted view and type shift-f, we can see the N/PMOS with the value of L/W.

extract layout to spice i
Extract Layout to Spice (I)
  • For the analog artist, do the following 3 steps:
  • Open .cshrc and find the line:setenv CDS_Netlisting_Mode=Digitalchange “Digital” to “Analog”
  • Open .simrc and find the line: simNlpGlobalLibName=samplechange “sample” to “analogLib”
  • In divaExt.rul,change the capacitor model to “pcapacitor”change the transistor model to “pmos4” and “nmos4”.
extract layout to spice ii
Extract Layout to Spice (II)
  • For the digital artist, do the following 3 steps:
  • Open .cshrc and find the line:setenv CDS_Netlisting_Mode=Analogchange “Analog” to “Digital”
  • Open .simrc and find the line: simNlpGlobalLibName=analogLibchange “analogLib” to “sample”
  • In divaExt.rul,change the capacitor model to “capacitor”change the transistor model to “pfet” and “nfet”.
cdl out step 2
CDL OUT – step 2


preparation to run timemill
Preparation to Run TimeMill
  • 執行檔:
    • spice2erun
    • printwlrun
    • gentechrun
    • timerun
  • The files required to run TimeMill
    • *.sp: your spice file
    • *.cfg:設定電源電壓及欲觀察的節點
    • *.io:設定test pattern的輸入檔案及IO pin name
    • *.vec:設定測試pattern
    • *.ctl: control file
    • Ls35_4_1.l: TSMC spice model
      • *表示待測試電路的名稱,如果是circuit是an4,則*=an4
      • 這些檔案都可以從網頁上抓到,在接下來的範例中以an2 cell為例。
running timemill step 1
Running TimeMill – step 1
  • 透過spice2e 將 an2 轉成 an2.ntl ( EPIC 檔案格式)
    • 將 an2.sp , spice2erun拷貝至工作站下同一目錄
    • 將 spice2erun 的屬性更改為可執行並執行
  • " spice2erun 內容,共三行 "
    • echo "spice2e running!"
    • spice2e -i an2.sp -o an2.ntl -f hspice -1
    • echo "spice2e end!"
  • 輸出檔案 an2.ntl

注意:mos的長寬都要改成以u來表示。如 l=3.5e-7 要改成 l=0.35u。

running timemill step 2
Running TimeMill – step 2
  • 透過 printwl,根據 an2.ntl 產生 an2.wl1
    • 將 an2.ntl , printwlrun拷貝至工作站下同一目錄
    • 將 printwlrun 的屬性更改為可執行並執行
  • " printwlrun 內容,共三行 "
    • echo "printWL running!"
    • printWL -n an2.ntl -m AN2 -o an2.wl
    • echo "printWL end!“
      • -m 後面是接spice檔中subckt的名稱
running timemill step 3
Running TimeMill – step 3
  • 根據 an2.wl1產生新的 an2.ctl
  • “ an2.wl1 內容,共八行 ”
    • %model
    • .model n nmos
    • .model p pmos
    • %parameters
    • N_LENGTH1 0.35
    • NW1 1.70
    • P_LENGTH1 0.35
    • PW1 2.65 3.30
  • 將an2.wl1整段複製到an2.ctl相對的地方
running timemill step 4
Running TimeMill – step 4
  • 透過 gentech 產生
    • 將 an2.ctl , ls35_4_1.l , gentechrun拷貝至工作站下同一目錄
    • 將 gentechrun 的屬性更改為可執行並執行
  • " gentechrun 內容,共三行 "
    • echo "begin: `date`"
    • gentech -c an2.ctl -t -f hspice -m -q
    • echo "end: `date`“
  • 輸出檔案是
running timemill step 5
Running TimeMill – step 5
  • 進行 timemill 模擬
    • 將 an2.ntl , , an2.cfg , , timerun
    • 拷貝至工作站下同一目錄
    • 將 timerun 的屬性更改為可執行並執行
  • " timerun 內容,共三行 "
    • echo "run timemill"
    • timemill -n an2.ntl -m AN2 -o an2 -c an2.cfg -p -d t -t 50
    • echo "end timemill"
  • 50是模擬的時間長度,跟 test pattern長度有關
running timemill step 51
Running TimeMill – step 5
  • 注意事項:將an2.ntl的n改成nch


; A B

radix 1 1

io i i

10 0 0

20 0 1

30 1 0

40 1 1



輸出檔案: an2.out

running timemill step 6
Running TimeMill – step 6


running timemill step 61
Running TimeMill – step 6



running timemill step 62
Running TimeMill – step 6



running timemill step 63
Running TimeMill – step 6