Semiconductor Device & Analysis Center Berlin University of ...

Section Semiconductor Devices / C. Boit ’ 

Semiconductor Device & Analysis Center 

Berlin University of Technology 

Christian Boit 

TUB Berlin University of Technology 

Sect. Semiconductor Devices 

Christian.Boit@TU-Berlin.DE 

1


Semiconductor Device & Analysis Center Berlin 

Scope: 

• Research: FA Techniques for Faster Turnaround 

- Edit techniques on devices 

- Physical interactions of devices for localization 

- Standard solutions (cook book etc.) 

- Device Design & Characterization 

• Education: Full Device Development Process 

- Semiconductor Devices in Basic Curriculum 

- Full Microelectronic Business Process (FET) 

- Failure Analysis, Power & Special Devices 

• Service: Commerical-like Application Lab 

- Lab unique for service of design verification and 

failure analysis processes from chip backside 

2



Resources: 

• 1 Lead Engineer (permanent) 

• 3 PhD Students based on educational track 

• 4 Technical Staff (permanent contracts) 

• More PhD Students per cooperation contracts 

• State of the Art tools Hamamatsu Phemos 1000, 

NPTest OPTIFIB, Agilent 83000 Tester 

• Device Simulation & Know How (FET, Power, PV) 

• Sample Preparation Mech, Chem Wet &Dry 

• 1000 sqft Small Clean Room Technology 

• More than 5000 sqft lab and office space 

3



Who we are 

Device Dynamics Make the Difference in Functional Analysis 

Challenges of Backside Approach 

Device Localization with Laser Stimulation 

Device Repair (Circuit Edit) with FIB 

Where we want to go 

4


Photon Emission Basics: Electroluminescence 

The Two Basic Mechanisms of Photon Emission in IC 

P/N Junction: 

Reverse Bias 

1) Deceleration: 

Radiant loss of 

energy gained in 

electrical field 

Leakage 

Current 

I 

Detection 

Limit 

V 

Forward Bias 

2) Injection: 

Radiant 

Interband 

Recombination 

5


Photon Emission Microscopy 

Direct defect identification: Gate oxide defect 

X5 

X25 

X0.8 

Emission images at magnification: 

X 100 

6


Substrate 

[µA] 

I sub 

Correlation of MOSFET Light Emission 

to Electrical Operation Mode 

current 

I D 

Gate voltage [V] 

Drain 

[mA] 

Light emission and substrate 

current vs. gate voltage 

Substrate 

Current 

Gate voltage [V] 

Light 

Intensity 

7


Dynamic Photon Emission in CMOS 

• Photon Emission in 

Switching Phase of FET 

• Required Time Resolution: 

30 - 40 ps 

• Measurement Challenge: 

~ 1 photon / 10 5 events 

•Stroboscopic Imaging: IC 

Signal Tracing 

All figures from J.C. Tsng, Picosecond 

imaging circuit analysis 

8


Design Verification: Signal Propagation in IC 

visualized with Dynamic Photon Emission 

t=3.876ns: 

t=4.080ns: 

t=6.800ns: 

Emission from a 

ring oscillator at 

various times. 

Example: ring oscillator: 

Three ‚optical waveforms‘ of switching 

induced light emission from neighbouring 

inverters of the ring oscillator; 

Vdd -> 0V: high intensity 

0V -> Vdd: low intensity 

All figures from J.C. Tsng, Picosecond imaging circuit analysis 

9


Design Verification & Failure Analysis: 

Identification and Localization of Erratic Device 

fail 

reference 

Time integrated image of light 

from a register file while 

running a test pattern 

producing a fail 

fail 

‚optical waveform‘ from normal 

and faulty latch pair 

All figures from J.C. Tsng, Picosecond 

imaging circuit analysis 

10


Why FA through Backside of the Die? 

New Packages 

Multi-Level Metallization 

LOC ( Lead On Chip) 

Flip-Chip 

Die 

Flip-chip substrate 

Data taken from Fujitsu 

11


Observability of ofSignals with Beam Techniques 

Drastically Reduced by byMulti Layer Wiring 

DatatakenfromN.Kujietal.,NTT,ESREF97 

Image taken from IBM Research Labs 

Cu 6 

Cu 5 

Cu 4 

Cu 3 

Cu 2 

Cu 1 

tungsten 1 

12


Challenge of Analysis Techniques 

Through Chip Backside: 

IR Optics Resolution vs. Feature Size 

13


Resolution 

of different 

immersion 

media 

gas, air (a), 

liquid, oil(b), 

solid, Si (c) 

14



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Who we are 






16


Beam Induced Device Stimulation 

Set Up: 

5678%-,) 

8!9 

51%#, 

*/,)&%: 

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.,;&,+4"*$ 

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17


Principle of Laser Induced Thermal Stimulation 

Electrical Signal 

responding to 

laser stimulation 


Transmission (%) 

Thermal Stimulation of Silicon Device by IR Laser 

Intraband Free Carrier Absorption : 

100 

10 

1 

0.1 

0.01 

Si indirect 

bandgap 

1.0 1.5 2.0 2.5 

IR Absorption in Highly Doped Layers: 

0.1 to 0.05% of 1.3µm Laser power 

(c) 

(a) 

(b) 

(d) 

Si thickness 

625µm 

Dopant Conc. 

x10 16 cm -3 

(a) 1.5 

(b) 33 

(c) 120 

(d) 730 

Wavelength (µm) 

Local Heating of 

Active Device 

19


Thermal Laser Stimulation in Metal Wire & in 

Semiconductor Device 

M2 

M1 

S/D, typ. 10 19 /cm 3 

M1 

Cap typ. 10 19 - 

Silicide 

Poly-Si 

10 20 /cm 3 

S/D 

well, typ. 10 17 /cm 3 

Si-Substrate, typ. 10 15 -10 16 /cm 3 

Interactions: 

Wiring: 

Device: 

20


Thermal Laser Stimulation in Metal Wire & in 

Semiconductor Device 

Heat 

λ=1.3 m laser illumination 

Interactions: 

Wiring: 

Voltage Alteration 

Resistive Change 


21


Heat 

reflected 

beam 

Heat 

Thermal Laser Stimulation 

in Metal Wire & in Semiconductor Device 

laser illumination, λ=1.3 m 

Interactions: 

Wiring: 




Performance 

Reduction 

- Mobility 

-Vτ 

- Speed 

22


Heat 

Heat 

Heat 

t=1ms 

Thermal Laser Stimulation 

in Metal Wire & in Semiconductor Device 

Heat 

Interactions: 

Wiring: 




Performance 

Reduction 

- Mobility 

-Vτ 

- Speed 

23

Soft Defect Localization - FET 

24 

Source: Ed Cole 

Section Semiconductor Devices / C. Boit ’


Soft Defect Localization 

Soft Defect: Test Fail occurring 

only in special Environment 

TUB Research Result: 

Quantitative Investigation of FET Device Parametrics 

with Thermal Laser Stimulation to be submitted 10/03 

Source: 

Ed Cole 

25



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27


Outline: 

Who we are 






28


Previous Process 

Device Repair (Circuit Edit) with FIB: 

Short Redesign Loop and Access to Cells 

Circuit CircuitDesign 

Simulation Simulation 

Layout LayoutDesign 

Mask MaskProduction 

Engineering EngineeringSample 

Evaluation Evaluation 

Production Production 

Quality QualityControl 

FIB Deposition of 

Probing Pads for 

SRAM Cell on 

Via1level 

(Prep: surface 

parallel polishing) 

FIB 

29


The OptiFIB Column 

Photon Beam 

Ion Beam 

Coaxial Photon-Ion Microscope 

Simultaneous 

Imaging & Editing 

Photon Image 

Ion Editing 

100nm FIB 

Placement Accuracy 

30


M5 

M4 

M3 

M2 

M1 

FIB Editing of ICs through Si Backside 

2-5µm 

Silicon 

Substrate 

48 µm 

FIB Trench 

Very thin remaining bulk Si 

- Risks: Flatness, Endpoint, Navigation 

ILD1 

ILD0 

Transistor Level 

31


Voltage Contrast by Silicon Active Volume 

TUB Research 

Result: 

FIB Image 

Contrast of n- 

Wells for 

- Endpoint Control 

and 

- Navigation 

to be presented at 

ESREF & ISTFA 03 

32


M1 

Endpoint Detection for Active Si Volume 

M1 

n+ n+ - p+ p+ 

+ 

+ 

p-well 

- n-well 

+ + + + + + + + + 

- 

- - - - 

Si-p-Substrate 

- - - - 

Scanned Ion 

Beam 

700nm 

4 µm 

• Ion Beam 

removes 

material 

33


M1 


M1 

n+ n+ - p+ p+ 

+ 

+ 

p-well 

- n-well 

+ + + + + + + + + 

- 

- - - - 


- - - - 

+ + + + + + + + + 

700nm 

4 µm 

• Ion Beam 

removes 

material 

• and implants 

Ga ions into 

the back 

surface. 

34


M1 


M1 

n+ n+ - p+ p+ 

+ 

+ 

p-well 

- n-well 

+ + + + + + + + + 

- 

- - - - 


- - - - 

+ + + + + + + + + 

e- 

e- 

700nm 

4 µm 

• Ion Beam 

removes 

material 

• and implants 

Ga ions into 

the back 

surface. 

• Influence of 

SCR causes 

contrast of 

secondary 

particle 

emission rate 

35


Semiconductor Device & Analysis Center Berlin: 

Wherewewanttogo 

• Establish TUB as Solution Center for Advanced 

Analysis Problems in Electronic Devices 

Microelectronics: 

• Dynamics of Device and Analysis 

• Pervasive Techniques (i.e. SQUID) 

• Focused Ion Beam Processes for Edit in Si 

Power Devices & Compound Semiconductors: 

• Adaption of Localization Techniques to Discrete 

Devices, Band Gap and Mechanisms of Direct SC 

• Adaption of FIB processes to Material Components 

36

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