5本公众号【读芯树:duxinshu_PD】主要介绍数字集成电路物理设计相关知识,才疏学浅,如有错误,欢迎指正交流学习。
这是集成电路物理设计的第六个系列【Physical Verification】的第十二篇文章,本篇文章主要介绍PERC相关内容:
01
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什么是PERC?
PERC相关内容参考:Physical Verification 介绍——PERC(1)
02
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Topology Checker
Primary ESD Definition (N1) : Drain 之间连接IO PAD (中间没有电阻), source和bulk连接ground,gate端的连接没有要求,如果有多个MOS连接相同的IO net,则需要计算所有MOS的宽度之和。
Primary ESD Definition (D1+D2): HIA diode器件,如果有多个Diode器件连接相同的IO net,则需要计算所有Diode的周长和。
ESD Resistor: resistance calculation
使用SPICE Model (TT corner, 25C, Vtypical)计算电阻阻值
ESD电阻识别:ESD电阻器件,电阻的两端连接PAD和MOS的Gate端,电阻可以串联或并联。
Secondary ESD Device:
Power Clamp: PMOS (Pcs) 的source和bulk连接相同的Power Net,drain连接Ground Net上;NMOS (Ncs) 的source和bulk连接相同的Ground Net,drain连接Power Net上。PMOS/NMOS的gate不直接连接Power/Ground Net上,一般通过ESD触发探测电路连接。
Back to Back Diode: 在不同的VSS之间需要插入bypass discharge cells 以避免电路内部间的ESD损伤。
Cross Domain: PERC探测MOS的source/drain的power/ground信息,并标记为path1 and path2。
如下图所以,如果只有Active Clamp1或者Active Clamp2,则必须增加RESD和dual Diode;如果不仅有Active Clamp1还有Active Clamp2,则不用增加RESD和dual Diode。
03
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Layout (LDL) Checker
Parasitic NPN/PNP ESD spacing rules: single stage snnapback NMOS IOPAD to the any other signal PAD.
OD injector: Any active OD directly connected to I/O PAD.
04
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Current Density Checker
Primary Path: (D1 D2 N1)
Total current injecting from source side is large.
Checking backend layer connected between IO pad and primary ESD device.
Checking path stopped before ESD resistor.
Total current injecting from source side is small.
Checking current density from ESD resistor (RESD) to secondary ESD device.
Includes ESD resistor and backend layer.
Full Path CD Check (default):
I/O Pad to Power/Ground Pad through promary ESD device.
RESD to Power/Ground Pad through secondary ESD device.
Power Pad to Ground Pad through Power Clamp.
Two Ground Pads through B2B diode connection.
Basic Path CD Check: (by disable CHECK_FULL_PATH_CD)
05
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P2P Checker
P2P Checker: Point to Point Resistance Checker
检查从IO pad到最近的Power Clamp的Power Bus Line上的电阻 (R1 + R2 + R4)
检查从IO pad到最近的Power Clamp的Ground Bus Line上的电阻 (R1 + R5 + R6)
检查从Power Pad到最近的Ground Pad的电阻(R3 + R4 + R6 + R7)
检查二级ESD Diode到Power Clamp的电阻(R2' / R5')
检查LUP pick-up ring到最近的Power/Ground Pad的电阻。
P2P Check Flow
06
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CNOD Checker
CNOD Checker:检查P/N type的MPODE的关断连接是否正确(PMPODE的gate和bulk连接VDD; NMPODE的gate和bulk连接VSS)
calibre -perc -hier -tyrbo -hyper perc.top
###perc.top
LAYOUT SYSTEM GDSII
LAYOUT PATH 'design.gds.gz'
LAYOUT PRIMARY design
PERC NETLIST LAYOUT
TEST DEPTH 0
PORT DEPTH 0
PERC REPORT 'perc.rpt'
PERC REPORT MAXIMUM ALL
PERC REPORT PLACEMENT LIST MAXIMUM ALL
PERC REPORT OPTION NO_NET_TYPE NO_DEVICE_PIN
DFM DATABASE 'dfmdb' OVERWRITE REVISIONS [ALL]
DRC ICSTATION YES
LVS EXECUTE ERC NO
LAYOUT PROCESS BOX RECORD YES
LAYOUT INPUT EXECPTION SEVERITY TESTSTRING_ASTRING 1
LAYOUT INPUT EXECPTION SEVERITY MISSING_REFERENCE 1
LVS SPICE SCALE X PARAMETERS YES
INCLUDE './perc.lvs'
INCLUDE './perc.rules'
07
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参考文献
Calibre PERC User Guide
Foundary Documentation
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