PCell Generators
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PCell generators are created to draw layouts of various circuit components. These are written in SKILL and can be modified based on a given technology or specifications. See this How to install a PCell for instructions on how to install a PCell generator into the Cadence environment.
Capacitor PCell
This PCell generator draws a capacitor in AMI C5N 0.5u technology using the scalable CMOS rules in the NCSU CDK.
pcDefinePCell(list(ddGetObj("AMI_06_Layout") "cap" "layout")
((Width float 2.4)
(Length float 2.4)
(numRows int 1)
(numCols int 1)
(DrawPOLY1 boolean "TRUE")
(DrawM1 boolean "TRUE")
(AbutM1 boolean "TRUE")
(ShieldWithM2 boolean "FALSE")
(ShieldWithNWELL boolean "FALSE")
(CapSeparation float 0.9)
)
let(
(Width Length numRows numCols DrawPOLY1 DrawM1 AbutM1 ShieldWithM2 ShieldWithNWELL CapSeparation
pcLib pcParameters pcParamProp pcLayer pcPurpose pcList
Ox Oy stepX stepY cntStepX cntStepY totalContactsX totalContactsY
POLY2W PLY2SP P2EOCT BCEOTC CNTW CNTSP
layerM1 layerM2 layerPOLY1 layerPOLY2 layerCNT layerNFIELD layerTUB layerCAPM
)
; Technology Rules
POLY2W = 2.4 ; Min POLY2 Width
PLY2SP = 0.90 ; Min POLY2 SPacing
P2EOCT = 0.90 ; Min POLY2 Enclosure of CnT (DRC rules do not really tell what this should be)
BCEOTC = 1.5 ; Min BotCap plate Enclosure Of TopCap plate
CNTW = 0.60 ; Min CNT Width
CNTSP = 0.90 ; Min CNT Spacing
; Calculations
pcLib = pcCellView->lib
pcParameters = (pcCellView->parameters)->value
Ox = 0.0
Oy = 0.0
; Get the PCell parameters.
pcParamProp = car(exists(prop pcParameters ((prop->name) == "Width")))
Width = pcParamProp->value
pcParamProp = car(exists(prop pcParameters ((prop->name) == "Length")))
Length = pcParamProp->value
pcParamProp = car(exists(prop pcParameters ((prop->name) == "numRows")))
numRows = pcParamProp->value
pcParamProp = car(exists(prop pcParameters ((prop->name) == "numCols")))
numCols = pcParamProp->value
pcParamProp = car(exists(prop pcParameters ((prop->name) == "DrawPOLY1")))
DrawPOLY1 = (pcParamProp->value == "TRUE")
pcParamProp = car(exists(prop pcParameters ((prop->name) == "DrawM1")))
DrawM1 = (pcParamProp->value == "TRUE")
pcParamProp = car(exists(prop pcParameters ((prop->name) == "AbutM1")))
AbutM1 = (pcParamProp->value == "TRUE")
pcParamProp = car(exists(prop pcParameters ((prop->name) == "ShieldWithM2")))
ShieldWithM2 = (pcParamProp->value == "TRUE")
pcParamProp = car(exists(prop pcParameters ((prop->name) == "ShieldWithNWELL")))
ShieldWithNWELL = (pcParamProp->value == "TRUE")
pcParamProp = car(exists(prop pcParameters ((prop->name) == "CapSeparation")))
CapSeparation = pcParamProp->value
; Check the parameter values and make adjustments
if((Length < POLY2W) then Length = POLY2W)
if((Width < POLY2W) then Width = POLY2W)
if((CapSeparation < PLY2SP) then CapSeparation = PLY2SP)
stepX = Width + CapSeparation
stepY = Length + CapSeparation
C5N = nil
SCMOS = t
; Define layer constants
if((C5N == t) then
layerM1 = 9
layerM2 = 11
layerCNT = 8
layerPOLY1 = 4
layerPOLY2 = 37 ; 26
layerNFIELD = 3
layerTUB = 1
layerCAPM = 56
else if((SCMOS == t) then
layerM1 = 45
layerM2 = 50
layerCNT = 59
layerPOLY1 = 35
layerPOLY2 = 37
layerNFIELD = nil
layerTUB = 12
layerCAPM = nil
))
; Draw POLY1 for the bottom plate of the capacitor.
if((DrawPOLY1 == t) then
pcLayer = layerPOLY1
pcPurpose = "drawing"
pcList = list((Ox-BCEOTC:Oy+BCEOTC) (Ox+(numCols-1)*stepX+Width+BCEOTC:Oy-(numRows-1)*stepY-Length-BCEOTC))
pcInst = dbCreateRect(pcCellView list(pcLayer pcPurpose) pcList)
)
; Draw CAPM pseudo layer.
if((layerCAPM != nil) then
pcLayer = layerCAPM
pcPurpose = "drawing"
pcList = list((Ox-BCEOTC:Oy+BCEOTC) (Ox+(numCols-1)*stepX+Width+BCEOTC:Oy-(numRows-1)*stepY-Length-BCEOTC))
pcInst = dbCreateRect(pcCellView list(pcLayer pcPurpose) pcList)
)
; Draw POLY2 for the top plate of the capacitor.
pcLayer = layerPOLY2
pcPurpose = "drawing"
for(j 0 numRows-1
for(i 0 numCols-1
pcList = list((Ox+i*stepX:Oy-j*stepY) (Ox+i*stepX+Width:Oy-j*stepY-Length))
pcInst = dbCreateRect(pcCellView list(pcLayer pcPurpose) pcList)
)
)
; Draw M1 over the top plate of the capacitor.
if((DrawM1 == t) then
pcLayer = layerM1
pcPurpose = "drawing"
if((AbutM1 == t) then
pcList = list((Ox:Oy) (Ox+(numCols-1)*stepX+Width:Oy-(numRows-1)*stepY-Length))
pcInst = dbCreateRect(pcCellView list(pcLayer pcPurpose) pcList)
else
for(j 0 numRows-1
for(i 0 numCols-1
pcList = list((Ox+i*stepX:Oy-j*stepY) (Ox+i*stepX+Width:Oy-j*stepY-Length))
pcInst = dbCreateRect(pcCellView list(pcLayer pcPurpose) pcList)
)
)
)
)
; Draw M2 over the capacitor for shielding.
if((ShieldWithM2 == t) then
pcLayer = layerM2
pcPurpose = "drawing"
pcList = list((Ox-BCEOTC:Oy+BCEOTC) (Ox+(numCols-1)*stepX+Width+BCEOTC:Oy-(numRows-1)*stepY-Length-BCEOTC))
pcInst = dbCreateRect(pcCellView list(pcLayer pcPurpose) pcList)
)
; Draw NWELL under the capacitor for shielding.
if((ShieldWithNWELL == t) then
pcLayer = layerTUB
pcPurpose = "drawing"
pcList = list((Ox-BCEOTC:Oy+BCEOTC) (Ox+(numCols-1)*stepX+Width+BCEOTC:Oy-(numRows-1)*stepY-Length-BCEOTC))
pcInst = dbCreateRect(pcCellView list(pcLayer pcPurpose) pcList)
if((layerNFIELD != nil) then
pcLayer = layerNFIELD
pcPurpose = "drawing"
pcInst = dbCreateRect(pcCellView list(pcLayer pcPurpose) pcList)
)
)
; Draw contacts from POLY2 to M1.
pcLayer = layerCNT
pcPurpose = "drawing"
for(j 0 numRows-1
for(i 0 numCols-1
cntStepX = cntStepY = CNTW + CNTSP
totalContactsX = fix((Width-(2*P2EOCT+CNTW)+cntStepX+0.00001)/cntStepX)
offsetX = (Width - (cntStepX*(totalContactsX-1.0)+(2*P2EOCT+CNTW))) / 2.0
totalContactsY = fix((Length-(2*P2EOCT+CNTW)+cntStepY+0.00001)/cntStepY)
offsetY = (Length - (cntStepY*(totalContactsY-1.0)+(2*P2EOCT+CNTW))) / 2.0
for(k 0 totalContactsX-1
for(l 0 totalContactsY-1
pcList = list((Ox+P2EOCT+i*stepX+k*cntStepX+offsetX:Oy-P2EOCT-j*stepY-l*cntStepY-offsetY) (Ox+P2EOCT+CNTW+i*stepX+k*cntStepX+offsetX:Oy-P2EOCT-CNTW-j*stepY-l*cntStepY-offsetY))
pcInst = dbCreateRect(pcCellView list(pcLayer pcPurpose) pcList)
)
)
)
)
t
)
)
