1

Electromagnetic Field Visualization System for IC/Package Design Based on

Optical Techniques

Mizuki IwanamiJisso and Production Technologies Research Laboratories,

NEC Corporation

Contents

2

1. Background and motivation

2. Probing system: Fiber-Edge Magneto-Optic/Electro-Optic(FEMO/EO) Probe

3. Objective

4. Magnetic near-field maps over fine meander circuits 4-1. Probe head and device under test4-2. Mapping results4-3. Verification of measured results by electromagnetic

field simulator

5. Electromagnetic near-field measurements over active devices5-1. Measurement results of radiated emissions and

near-fields arising from a PCB5-2. Magnetic/electric near-field maps over an LSI chip

6. Conclusions

3

Background and motivation

It is highly desirable to prevent the problems in the early stages of design and packaging of electronic components.

Signal integrity

Power integrity

EMI

EM coupling between circuits

4

Background and motivation

Conventional circuit performance evaluation/testing techniques such as

a network analyzer and a TDR It is difficult to identify the concrete location

of the faulty components inside the circuits. They cannot give direct information about

an EM coupling position and individualdecoupling capacitor performance.

Microscopic near-field probe

Sensor device

Wave guide

Decoupling capacitor Die

Die

Interposer

GroundPower

5

Background and motivation

Near-field probing technique is one of indispensable techniques.

Development and evaluations of a near-field probe that utilizes optical measurement techniques.

RequiredperformanceLow

invasiveness

Wide bandwidth

High spatial resolution

High sensitivity

FEMO/EO probing system

6

All apparatuses in the optical system are connected by optical fibers.→ Free from optical alignment

The probe head consists of an optical fiber and a minute crystal.→ Superior low-invasiveness→ High spatial resolution

Laser light source(CW, 1.55 µm)

Polarization controller

Photo-detector

RF spectrum analyzer

DUT

Optical fiber

MO/EO crystal

Analyzer Optical circulator

Optical amplifier

Single mode fiber

MO/EO crystal

Probe head

Dielectric mirror

xy

z

Optical amplifier

MO probe: detect HzEO probe: can detect all electric field elements by appropriate selection of the crystal

7

Objective

Development and application of high performance near-field probing system toward the high-speed and low-noise design of ICs/packages.

8

Magnetic near-field maps over fine meander circuits

Probe head and device under test (DUT)

9

15 m

m

Probe head Single mode optical fiber

BiRIG11 µm

DUT for near-field mappings130 mm

140

mm

PCB

Chip

MSL(50 Ω)

50 Ω

SMAconnector

15 mm

270 µm270 µm

L/S 20 µm

L/S 10 µm

Frequency response of the FEMO probe

10

-130-125-120-115-110-105-100

-95-90-85-80

10 100 1000 10000Frequency [MHz]

MO

Sig

nal [

dBm

]

Noise level

2.5 GHzProbe

3 µm

Microstrip line

The range where the signal level undulation stays within 3 dB. 2.5 GHz

11

X-Z near-field maps

- 1 3 8 .0- 1 3 7 .0- 1 3 6 .0- 1 3 5 .0- 1 3 4 .0- 1 3 3 .0- 1 3 2 .0- 1 3 1 .0- 1 3 0 .0- 1 2 9 .0- 1 2 8 .0- 1 2 7 .0- 1 2 6 .0- 1 2 5 .0- 1 2 4 .0- 1 2 3 .0- 1 2 2 .0- 1 2 1 .0- 1 2 0 .0- 1 1 9 .0- 1 1 8 .0- 1 1 7 .0- 1 1 6 .0- 1 1 5 .0- 1 1 4 .0- 1 1 3 .0- 1 1 2 .0- 1 1 1 .0- 1 1 0 .0- 1 0 9 .0- 1 0 8 .0- 1 0 7 .0- 1 0 6 .0- 1 0 5 .0- 1 0 4 .0- 1 0 3 .0- 1 0 2 .0- 1 0 1 .0- 1 0 0 .0- 9 9 .0 0- 9 8 .0 0- 9 7 .0 0- 9 6 .0 0- 9 5 .0 0- 9 4 .0 0- 9 3 .0 0- 9 2 .0 0- 9 1 .0 0- 9 0 .0 0- 8 9 .0 0- 8 8 .0 0

Line/Space 10 µm

[dBm]

10 µm

Exp.

Cal.10 MHz

-88

-138

DUT

Chip

PCB

Scan

3～15 µm

xy

z

Probe

X-Z near-field map

12

1 GHz

- 1 3 5 .0- 1 3 4 .0- 1 3 3 .0- 1 3 2 .0- 1 3 1 .0- 1 3 0 .0- 1 2 9 .0- 1 2 8 .0- 1 2 7 .0- 1 2 6 .0- 1 2 5 .0- 1 2 4 .0- 1 2 3 .0- 1 2 2 .0- 1 2 1 .0- 1 2 0 .0- 1 1 9 .0- 1 1 8 .0- 1 1 7 .0- 1 1 6 .0- 1 1 5 .0- 1 1 4 .0- 1 1 3 .0- 1 1 2 .0- 1 1 1 .0- 1 1 0 .0- 1 0 9 .0- 1 0 8 .0- 1 0 7 .0- 1 0 6 .0- 1 0 5 .0- 1 0 4 .0- 1 0 3 .0- 1 0 2 .0- 1 0 1 .0- 1 0 0 .0- 9 9 .0 0- 9 8 .0 0- 9 7 .0 0- 9 6 .0 0- 9 5 .0 0- 9 4 .0 0- 9 3 .0 0- 9 2 .0 0- 9 1 .0 0- 9 0 .0 0- 8 9 .0 0- 8 8 .0 0- 8 7 .0 0- 8 6 .0 0- 8 5 .0 0

[dBm]

20 µm

-85

-135

Scan

Current

Exp.

Line/Space 20 µm

X-Y near-field maps

13

-60

-40

-20

0

0 1 2 3

Frequency [GHz]

|S11

| [dB

]

2.46 GHz

|S11| of the PCB

Scan area

Current

-150.0-148.8-147.6-146.4-145.2-144.0-142.8-141.6-140.4-139.2-138.0-136.8-135.6-134.4-133.2-132.0-130.8-129.6-128.4-127.2-126.0-124.8-123.6-122.4-121.2-120.0-118.8-117.6-116.4-115.2-114.0-112.8-111.6-110.4-109.2-108.0-106.8-105.6-104.4-103.2-102.0-100.8-99.60-98.40-97.20-96.00-94.80-93.60-92.40-91.20-90.00

-145.0-143.8-142.6-141.4-140.2-139.0-137.8-136.6-135.4-134.2-133.0-131.8-130.6-129.4-128.2-127.0-125.8-124.6-123.4-122.2-121.0-119.8-118.6-117.4-116.2-115.0-113.8-112.6-111.4-110.2-109.0-107.8-106.6-105.4-104.2-103.0-101.8-100.6-99.40-98.20-97.00-95.80-94.60-93.40-92.20-91.00-89.80-88.60-87.40-86.20-85.00

10 MHz 2.46 GHz

50 µm

-85

-145

[dBm]-90

-150

[dBm]

Line/Space 20 µm

14

Verification of measured results by electromagnetic field simulator

Simulated maps of the amplitude of Hz at nearby the middle position of the circuit.

1 GHz

These results suggest that the measured near-field maps are accurate.

X-Z map

xy

z2.6 GHz Line/Space 20 µm meander circuit

X-Y mapdielectric

Ground plane

15

Electromagnetic near-field measurements over active devices

DUT for near- and far-fields evaluations

16

LSI Package (304 pin QFP) 180 mm

180 mmD-F/F

CPU

RAMD-F/F

I/O (3mA)

I/O (8mA)

I/O (12mA)

Width/interval of pins200 µm/500 µm

LSIpackage

Decouplingcapacitor

Signal trace （20 - 60 mm,open termination） Ground

Signal

Power

Six layer board (dielectric: FR-4, total thickness: 1.4 mm)

Ground

Signal

Ground

Radiated electric field strength

17

05

1015202530354045

0 200 400 600 800 1000

Frequency [MHz]

Rad

iate

d Em

issi

on [d

B µV

/m]

I/O circuit operationOutput voltage for traces: 3.3 V/0 V (rectangle, 12.75 MHz)

Anechoic chamber

Antenna

3 m

Electromagnetic wave absorber

PCB

High-level emissions are observed at 12.75 x 2n MHz.

Magnetic near-field distributions over the LSI package pins

18

D-F/F

CPU

RAMD-F/F

I/O

Pin No. 1 Pin No. 40

-25

-20

-15

-10

-5

0

0 5000 10000 15000 20000 25000

Position [µm]

Nor

mal

ized

MO

Sig

nal [

dB]

Pin No. 1 Pin No. 40

12.75 MHz

QFP

127.5 MHz

-10

-5

0

5

10

15

0 5000 10000 15000 20000 25000

Position [µm]

Nor

mal

ized

MO

Sig

nal [

dB]

I/O circuit operation

All peaks are due to the magnetic fields generating from the pins for a power or a ground

The probe has the capability for investigating circuit failure and an EMI source.

240 µm

400 µm 50 µm

Scan(50 µm pitch)

200 µm500 µm

Probe

LSI package pin

Frequency dependence of MO signals

19

-130

-120

-110

-100

-90

-80

-70

0 100 200 300

Frequency [MHz]

MO

Sig

nal [

dBm

] between VDD and GND pinsbetween I/O pins

Noise level

12.75×2n MHz

≒1 µm

LSI package pin

BiRIG160 µm

Fixing

Probe (Measurable bandwidth is over 10 GHz)

Measurement frequencies: multiples of 12.75 MHz

Between power and ground pins: high-level signals are observed at 12.75 x 2n MHz(Same feature as the electric far-field characteristic)

This suggests that the origin of the high-level electric field radiation is a current flowing in the power supply system of the I/O circuits.

LSI chip for near-field measurements

20

Decoupling capacitor areaLogic circuit area

10.4 mm

Printed circuit board (10 cm)

Quad flat package

LSI chip

Power/ground line for logic circuitsWidth of horizontal lines : 1.2 µmWidth of vertical lines : 10 µm

Magnetic/electric near-field maps over an LSI chip

21

Power/ground line

Magnetic field: strong intensity above the power supply systemElectric field: strong intensity above the signal system⇒ This suggests that detail SI/PI analyses can be performed by

the EO/MO probing technique.

Magnetic field: strong intensity above the power supply systemElectric field: strong intensity above the signal system⇒ This suggests that detail SI/PI analyses can be performed by

the EO/MO probing technique.

Decoupling capacitor

Logic circuit

Power/ground line

Power/ground line

0 500 1000 1500 2000 2500 30000

500

1000

1500

2000

2500

X Position [µm]

Y P

ositi

on [µ

m]

-179.0-177.0-175.0-173.0-171.0-169.0-167.0-165.0-163.0-161.0-159.0-157.0-155.0-153.0-151.0-149.0-147.0-145.0-143.0-141.0-139.0-137.0-135.0-133.0-131.0-129.0-127.0-125.0-123.0-121.0-119.0-117.0-115.0-113.0-111.0-109.0-107.0-105.0-103.0-101.0-99.00-97.00-95.00-93.00-91.00-89.00-87.00-85.00-83.00-81.00-79.00-79

-179

-129

[dBm]

0 500 1000 1500 2000 2500 30000

500

1000

1500

2000

2500

-172.0-170.6-169.2-167.8-166.4-165.0-163.6-162.2-160.8-159.4-158.0-156.6-155.2-153.8-152.4-151.0-149.6-148.2-146.8-145.4-144.0-142.6-141.2-139.8-138.4-137.0-135.6-134.2-132.8-131.4-130.0-128.6-127.2-125.8-124.4-123.0-121.6-120.2-118.8-117.4-116.0-114.6-113.2-111.8-110.4-109.0-107.6-106.2-104.8-103.4-102.0

X Position [µm]

Y P

ositi

on [µ

m]

-102

-172

-137

[dBm]

Magnetic field distribution

Clock frequency: 50MHzCircuit operation frequency:25 MHzMeasurement frequency:50 MHz

Electric field distribution

Due to decoupling capacitor

Conclusions

22

We introduced a wideband MO probe with a 10-µm-class spatial resolution.

GHz-region magnetic near-fields over a fine circuit were successfully mapped.

The potential of the probe for near-field characterization andEMI source evaluation of an active device was shown.

These results demonstrate that the FEMO/EO probing techniquecan be an effective tool toward an optimum design/packagingof electronic components.

Acknowledgement

23

This work was performed under the management of ASETin the basic plan of Research and Development on UltraHigh-Density Electronics System Integration supported byNEDO.

This work was performed under the guidance and cooperationof Tsuchiya lab of the University of Tokyo.

References

24

S. Wakana, T. Ohara, M. Abe, E. Yamazaki, M. Kishi, and M. Tsuchiya, “Fiber-Edge Electrooptic/MagnetoopticProbe for Spectral-Domain Analysis of Electromagnetic Field”, IEEE Transactions on Microwave Theory and Techniques, Vol. 48, No. 12, pp. 2611-2616 (Dec. 2000).

E. Yamazaki, H. Park, S. Wakana, M. Kishi, and M. Tsuchiya, “Implementation of Magneto-Optic Probe with > 10 GHz Bandwidth”, Japanese Journal of Applied Physics, Vol. 41, Part 2, No. 7B, pp. L864-L866 (July 2002).

E. Yamazaki, S. Wakana, M. Kishi, and M. Tsuchiya, “High Frequency Magneto-Optic Probe Based on BiRIGRotation Magnetization”, IEICE Transactions on Electronics, Vol. E 86-C, No. 7, pp. 1338-1344 (July 2003).

M. Iwanami, S. Hoshino, M. Kishi, and M. Tsuchiya, “Magnetic Near-Field Distribution Measurements over FineMeander Circuit Patterns by Fiber-Optic Magneto-Optic Probe”, Proc. 2003 IEEE Symposium on ElectromagneticCompatibility (EMC2003), pp. 347-352, Boston (Aug. 2003).

M. Iwanami, E. Yamazaki, K. Nakano, T. Sudo, S. Hoshino, S. Wakana, M. Kishi, and M. Tsuchiya, “Magnetic Near-Field Measurements Over LSI Package Pins by Fiber-Edge Magnetooptic Probe”, IEEE Journal of LightwaveTechnology, Vol. 21, No. 12, pp. 3273-3281 (Dec. 2003).

S. Wakana, E. Yamazaki, S. Mitani, H. Park, M. Iwanami, S. Hoshino, M. Kishi, and M. Tsuchiya, “Performance Evaluation of Fiber-Edge Magnetooptic Probe”, IEEE Journal of Lightwave Technology, Vol. 21, No. 12, pp. 3292-3299 (Dec. 2003).

M. Iwanami, S. Hoshino, M. Kishi, and M. Tsuchiya, “Magneto-Optical Mapping of Near-Field Distributions over an LSI Chip”, Technical Digest of Seventh International Symposium on Contemporary Photonics Technology (CPT2004), J-4, pp. 167-168, Tokyo (Jan. 2004).

M. Iwanami, S. Hoshino, M. Kishi, and M. Tsuchiya, “Wideband Magnetooptic Probe with 10 µm-Class Spatial Resolution”, Japanese Journal of Applied Physics, Vol. 43, No. 4B, pp. 2288-2292 (Apr. 2004).

M. Iwanami, S. Hoshino, N. Masuda, M. Kishi, and M. Tsuchiya, “Visualization of High Frequency Electromagnetic Field over Fine Circuits by Magnetooptic/Electrooptic Probe”, IEICE Technical Report, CPM2005-88, pp. 19-24, in Japanese (Sept. 2005).