tuesday 3.1.1 1.00 pm 10712 tonti
DESCRIPTION
efuseTRANSCRIPT
-
Reliability, Design Qualification,and Prognostic Opportunity
of in Die eFuse
W.R. Tonti Ph.D./MBAFIEEEIEEE Director, Future Directions
-
OutlineIntroduction Drive to PHM
One Time Programmablen (OTP) eFuseDesign
Programming Conditions Reliability
Applications
Conclusion
-
IntroductionNeed for an electronic fuse
Laser (non-PHM) versus electronic (PHM)fuse
One Time Programmable (OTP) eFuse PHM, but 1 way street by design
Leveraging a failure mode: Electromigration
Integration in a standard CMOS process flow.
Base level fuse design
A statement of reliability
Typical use of the efuse
-
4
E Spectrum 2004er, W. Tonti
-
5
E Spectrum 2004er, W. Tonti
-
roduction: The need for an eFuseCircuit elements at time zero are not perfect. Circuit spares are esigned, tested and available for replacement. Fuses are needed o enable the replacement. Time zero PHM
Circuit trimming for process variances is needed to optimize erformance. Fuses serve in this optimization. Custom PHM
Electronic Chip ID (ECID) is very useful throughout a products life ycle. Fuses are used to encode a chips DNA.
PHM identification.
Products require unique personalization for a given customer. For xample the identical memory chip may be available in x8 or x16. uses can be used to personalize and deliver the correct ustomization.
Custom PHM
Non volatile data is an option whenever fuses are provided. Trusted PHM
-
eFuse at 100,000 Feet
The eFuse advantage are: Enabled at any level of assembly. They function within the product. Do not require an external programming
stimulus Have autonomic capability They can be used to make a reliable
product more reliable
-
eFuse versus Laser Fuse
eFuse scales with technology critical dimension
Laser Fuse does dot scale
eFuse enables autonomic repair capability PHM
Laser Fuse cannot be used to enable autonomic repair.
eFuse relies on front end process technology, Laser fuse relies on back end process technology
eFuse is designed to not impact the back end wiring channels.
Laser fuse-boxse-box
* F T t i l IEEE 2007 IRPS R K th d C Ti
(*)
-
OTP eFuse
Latch Trip Point
E Fuse RIntrinsic
Rintrinsic + Rsystem
Ipgm limited
Programming Current is Established by T0 FuseResistance
Incomplete programmingresets T0 fuse resistance
Not possible to reprogram
-
esign for ElectromigrationInvestigate a fuse programming solution that we can electrically control
Control is governed by electromigtaion of a low resistance species
Design of a structure where
Electrically Programmable eFuse Using Electromigration in Silicides
EqZkT
TDNF
*)(=he flux of a migrating species
mic density diffusion coefficient of the migrating species (Silicide)
fective charge
cal Electric Field tromigration to initiate 0 F
n be influenced by either changing the diffusion species gradient, D , anging the thermal gradient the species sees, T electrically programmed eFuse one can easily control the thermal gradient the design of the Cathode, Link, and Anode. Electrical optimization through the f the programming delivery system, ie the programming transistor provides an al control for establishing the thermal gradient. Using the thermal insulating es of shallow trench isolation completes the loop for controlled electromigration.
This methodology leads to physical eFuse scaling
-
Programmed eFuse in a standard CMOS flow
SilicidePolysilicon
Controlled EM in fuse linkogram Open
Shallow Trench Isolation: Dielectric
Si Substrate
AnodeCathode
Programmed eFuse: WSi2 0.2m technology
Reliability, and Desiqn Qualification of a Sub-Micron Tungsten Silicide eFuse W Tonti J Fifield J Higgins W Guthrie W Berry C Narayan IRPS 2004 Proceedings pg 152 156 IBM
-
Current
Fina
l R
eFUSE Programming ControlIntact Fuse
-
Actual post program resistance distributions
Latch Trip Point
Fail PassActual statistics affected by long tails, andErratic programmed bits due to ruptures and EM stringers
-
Fuse ApplicationsECID: PHM identificationPHM Repairs: Wafer, Module, Fielde-Odometer: PHM Electronic oil changePHM Autonomic Core control
Data, Thermal
-
mpedance Control Using eFusesUSPA 6141245 10/31/2000 USPA 6,243,283 6/5/2001 IBM
Bertin, Fifield, Hedberg, Houghton, Sullivan, Tomashot, Tonti
Teaches: In system customization.Trimming driver for exactimpedance matching.
PHM
-
hanging Machine function with eFuse
USPA 7,268,577 9/11/2007 IBM
Teaches: In system customization.Tamper proof, ability to lock out a hacker
PHM
-
V Memory ElementA 6,208549 3/27/2001 Xilinix
Rao, Voogel
ches: Trusted Dataelements.
PHM
-
Odometer Field Repair and replacement
USPA 7,287,177 10/23/2007 IBM
B i L t T ti V t
Teaches: Autonomic Repair using standard Product Rel model to anticipate failure and replacement.
PHM
-
Conclusions
eFuses are the electronic gateway to PHM
eFuse programming requires precise thermal control of the migrating species flux
eFuse use and application is limitless
Design and programming conditions of the eFuse ultimately determine long term reliability of the element
As the MOSFET evolves so will the eFuse
This element has enabled autonomic computing
-
AcknowledgementsClaude Bertin IBM (retired)Wayne Berry IBM (retired)J. Fifield IBMJ. Higgins IBM (retired)R. Kothadaraman IBMP. Farrar IBMS. Iyer IBMC. Narayan IBMW. Guthrie IBMR. Mohler IBMN. Robson IBMP. Spinney U. Maine OronoC. Tian IBM
This work was performed at the IBM Microelectronics,Division Semiconductor Research & Development Center Hopewell Junction NY 12533, and in Essex Junction VT 05452
-
Backups
-
Programming Conditions and Reliability
-
ramming Conditions Establish the Basis for ability
Vdd
Vgs
eFuse
Programming Transistor
Bookkeeping:
3 banks of fuses, 960 fuses/bank- 128 Bits for ECID- Fuse Read: latch trip point 5K
-
nm Programming Study: oltage and Temperature Variation
Initial Fuse Resistance Summary
0
1000
2000
3000
4000
5000
6000
7000
150 160 170 180 190 200 210 220 230 240 250 260 270
Resistance (ohms)
Freq
uenc
y22 oC
85 oC
ment: Analyze eFuse variation over programming voltage and temperature windowD Programming: Control Cell, nominal conditions.ts= cell 1, 16 bits=cell 3, 16 bits =cell 2, 16 bits = cell 4.grouping is repeated twelve times for a total of 768 bits experimentally programmed.: This leaves 64 additional bits that are NOT programmed.
m
nom high
T=nom
T=high
-
Programming SummaryCellm)
3K7K
Cell 1 (Vlow=T=nom)
Mean: 10.5KMedian: 6.9K: 119Min: 1.7KMax: 1.4M
Cell 2 (V=high,T=nom)
Mean: 39KMedian: 26K: 0.7KMin: 1.8KMax: 5M
Cell 3 (V=low,T=high)
Mean: 2.4KMedian: 2.35K: 5Min: 1.2KMax: 9.4K
Cell 4 (V,T=high)
Mean: 7.4KMedian: 7.2K: 20Min: 1.6KMax: 23K
All eFuse bits shown are passing
-
icide Migration Length vs Program Resistance
cide migrated length measured from the cathode-link interface- Application: ballast resistor
-
Actual eFuse circuit
Cross Coupled latchCurrent Controlled Latch
E-Fuse Decode
Igpm Regulation
Rasied to Pgmommon to a fuse bank)
solation Device
atch Prechargetrobe Iread via 74
Rfuse affectsprogramming
J.Fifield
*
*
-
Programming Transistor Control
The programming transistor power and device controlgoverns the effectiveness of the eFuse and its reliability
2 integrated fuses on polysilicon for low voltage 0.18m CMOS applications,lnitsky ISaadat A Bergemont P Francis Proceedings of the 1999 IEEE IEDM pg 765-768 National Semiconductor
-
Effect of programming pulse time (Vgs)Experiment: Vdd, Temp=nom. Programming pulse varied
ramming 25S 1mS 2mS 4mS dition
lt High Z Isolation Damage Conductive Conductive
-
eliability of a fuse with correct programming
Conditions Equivalent Product Lifetime Rationale
SRAM-a DRAM-b
130C/2.85V/192 hr, 100% duty 1.5E6 device hours 2.4E9 years Electrical Duty-c
140C/2.85V/500 hr, 50% duty 2E6 device hours 3.1E9 years Electrical Duty-c
-55/125C/500 cycles 43 years 43 years Coffin-Manson model -d
sumes 500 ps fuse query per 1000 clock cycles at 4 ns cycle sumes 400 ns fuse query at powerup, and 2 powerups per day mperature and voltage acceleration not included sumes minimum exponent of 5.5 for e.g. thin film cracking {1}, deltaT(field) = e.g. Tj = 105C and Toff = 20C, and 2 on/off per day
EIA Bulletin SSB-1
-
Fuse Scaling: Additional data
LW
|Pro
gram
ed R
esis
tanc
e| @
+0.
1V (o
hms)
100
1000
10000
1e+5
1e+6
1e+7
1e+8
1e+9
1e+10
1e+11
1e+12
1e+13
1e+14
fuse_D fuse_B fuse_C fuse_A fuse_F fuse_G fuse_H fuse_I fuse_E device
0.06 0.08 0.06 0.08 0.12 fuse length (um
0.6 0.8 0.9 1.2 fuse width (um)
se L Fuse W CA La, Lc
2 0.08 8 1
8 0.08 8 1
9 0.06 8 1
6 0.06 8 1
2 0.12 8 1
2 0.08 16 1
2 0.08 8 0.5
2 0.08 8 1
SHORT NECK
Cathode/AnodeThermal gradient
-
e doping, link length reliability effects
0.9 0.6 0.9 f
HN halo adder only P ext/halo L
HN halo adder only P ext/halo C
0.001
0.010.0070.005
0.003
0.002
0.10.070.05
0.03
0.02
10.70.5
0.3
0.2
1075
3
2
20
0.6 0.9 0.6 0.9
HN halo adder only P ext/halo
HN halo adder only P ext/haloPPN
NPPN
NLink length (m)Link dopingTerminal doping
ost programming Resistancevariation in N doped fuseal design constraint for latch trip point
Ratio of stressed to initial programming resistance- Higher variation in N doped fuse
-
Si2 eFuse program mechanism and Reliability
The Authors show a programmed eFuse Reliability does not degrade (A) represents Silicide melt, (B) represents Co migration to the anode, and C represents Quenching of the the programming, and an amorphous Si region formed in the fuse link. 488 hours of Runtime stress shows 100nA of eFuse movement, which is in the noise of the ATE.
Melt-Segregate-Quench Programming of Electrical Fuse,T S ki N Ot k K Hi S F ji P di f th 2005 IRPS 347 352 TOSHIBA
-
0.35m Polysilicon TiSi2 eFuse Reliability
Authors show HTOL results for eFuse that is programmed at nominal, low, and high programming currents. Some drift is noticed at other than optimal programmed level, indicating initial programming criterion is key for an optimized fuse geometry.
Lifetime Study for a Poly Fuse in a 0.35m Polycide CMOS Process,
-
5nm NiSi Polysilicon eFuseAuthors show 65nm fuses can be reliably programmed at -400C, 250C, and +1250C. Reliability data is limited to a 1000hr 2500C bake.
NiSi Polysilicon Fuse Reliability in 65nm Logic CMOS Technology,
-
Effects of Metal tracks over eFuse Minimum M1 Parallel Min. M2 Comb structure M2
M1 M1M2 TSTM2AM2B GND
-
al effects over fuse T0 (pre), T1 (post programming)
Minimal impact to all types of Metal tracks over a fuse bay.
Metal 1 current
Metal 2 serpentine current