EBIC, EBAC, CV, and Advanced Applications in SEM Nanoprobing October 2, 2008
Richard Stallcup Applications Manager Advanced Instrumentation for the Nanoscale
Applications Overview • • • • •
Probing Poly Si, Copper and Aluminum CV – capacitance vs voltage Bit Cell Characterization Temperature Characterization EBC – E Beam Characterization- EBIC/EBAC, Active Voltage Contrast
Advanced Instrumentation for the Nanoscale
Probing Poly Si, Copper and Aluminum
Vd-Id before (a) and after (b) optimizing the contact quality
• In situ tungsten silicide formation • Oxide removal- in situ sample prep. • Low force landing and ohmic contact Soft metal contact
Advanced Instrumentation for the Nanoscale
1Mhz CV Curve of 45nm Intel Penryn Gate
21.8fF
Base Line 0.2fF
Advanced Instrumentation for the Nanoscale
Bit Cell Characterization Vdd
Vdd
WL
WL
BLB
BL CL
CH Vss
Bit Cell Connections
Vss Word
Inv1
Inv2 Vss
Bit
• Low power mode
Vdd CH
• Rapid fault localization
CL
• Bit level analog pulsing Butterfly Connections Advanced Instrumentation for the Nanoscale
Bit Cell Test Theory and Results 1.50E-04 1.30E-04 1.10E-04 9.00E-05 7.00E-05
I Bit I Bitbar
5.00E-05 3.00E-05 1.00E-05 -1.00E-05 -3.00E-05 Def.
BITBAR BIT
Phase 1
Phase 2
Phase 3
Phase 4
1.5V
sweep 1.5V to 0V in 100 steps
sweep 0V to 1.5V in 100 steps
1.5V
sweep 0V to 1.5V in 100 steps
1.5V
1.5V
sweep 1.5V to 0V in 100 steps
Phase 1 initializes the data in the cell to 0. Measuring the read current vs. bitline voltage as we ramp it up. If the cell flips in this phase the cell is unstable.
Phase 2 writes the opposite data. When the cell writes we see a reversal in currents. This region identifies stability and read/write issues.
Advanced Instrumentation for the Nanoscale
In phase 3 the cell should contain the data equal to 1. Measuring the read current vs. bitbar voltage as it ramps up. If the cell flips the cell is unstable.
Similar to phase2 but for the opposite data.
Butterfly Probing Results Voltage Transfer Curves 1.2
1.2
(b)
(a) Read Vdd=1.0
1
SNM = 0.16 V VTC-1 Inv1
0.6
SNM = 0.28 V
0.8
CL (V)
CL (V)
0.8
Hold Vdd=1.0
1
0.6
0.4
0.4
VTC Inv2
0.2
0.2
0
0 0
0.2
0.4
0.6
0.8
1
CH (V)
Advanced Instrumentation for the Nanoscale
1.2
0
0.2
0.4
0.6
0.8
CH (V)
1
1.2
Temperature Characterization N XTOR at -20C and 100C 0.00004
Probing at -20C
0.000035
Probing at 100C
0.00003
Drain Current (A)
0.000025
0.00002
•
Characterizing transistors at subambient temperatures and high temperatures for extreme weather applications
•
Characterizing transistors at operating temperatures
•
Low/High temperature fails
•
The testing was done on a standard SRAM chip at -20C and 100C
•
Higher drive currents were obtained at lower temperatures
0.000015
0.00001
0.000005
0 0
0.2
0.4
0.6
0.8
1
1.2
1.4
-0.000005 Drain Voltage (V)
Advanced Instrumentation for the Nanoscale
EBC Characterization
electron beam electron beam
nano probe nano probe
metal line current amplifier n-doped
electron hole pairs
current amplifier 109 V/A
via
injected
p-doped
charge
insulation
resistive defect
lower layer metal SEM display
SEM display
Two probe topside contact level PN Junction. The data was collected using the Zyvex nProber with the EBC package. Advanced Instrumentation for the Nanoscale
Advanced Instrumentation for the Nanoscale
Richard Stallcup Applications Manager
[email protected]
Interaction Volume vs Energy Low beam energy
Medium beam energy
High beam energy
700eV
1keV
5keV
SiO2 sample 20nm 35nm
440nm Advanced Instrumentation for the Nanoscale
