Terahertz Characterization of Electronic Components and

Comparison of Terahertz Imaging with X-ray Imaging Techniques

Kiarash Ahi, Navid Asadizanjani, Sina Shahbazmohamadi, Mark Tehranipoor and Mehdi Anwar

Department of Electrical and Computer Engineering

University of Connecticut

371 Fairfield Way, Storrs, CT 06269, United States

ABSTRACT

THz radiation is capable of penetrating most of nonmetallic materials and allows THz spectroscopy to be used to image

the interior structures and constituent materials of wide variety of objects including Integrated circuits (ICs). The fact

that many materials in THz spectral region have unique spectral fingerprints provides an authentication platform to

distinguish between authentic and counterfeit electronic components. Counterfeit and authentic ICs are investigated

using a high-speed terahertz spectrometer with laser pulse duration of 90 fs and repetition rate of 250 MHz with spectral

range up to 3 THz. Time delays, refractive indices and absorption characteristics are extracted to distinguish between

authentic and counterfeit parts. Spot measurements are used to develop THz imaging techniques. In this work it was

observed that the packaging of counterfeit ICs, compared to their authentic counterparts, are not made from

homogeneous materials. Moreover, THz techniques were used to observe different layers of the electronic components

to inspect die and lead geometries. Considerable differences between the geometries of the dies/leads of the counterfeit

ICs and their authentic counterparts were observed. Observing the different layers made it possible to distinguish

blacktopped counterfeit ICs precisely. According to the best knowledge of authors the reported THz inspection

techniques in this paper are reported for the first time for authentication of electronic components.

Wide varieties of techniques such as X-ray tomography, scanning electron microscopy (SEM), Energy Dispersive X-ray

Spectroscopy (EDS) and optical inspections using a high resolution microscope have also been being employed for

detection of counterfeit ICs. In this paper, the achieved data from THz material inspections/ THz imaging are compared

to the obtained results from other techniques to show excellent correlation. Compared to other techniques, THz

inspection techniques have the privilege to be nondestructive, nonhazardous, less human dependent and fast.

Keywords: THz imaging, THz time domain spectroscopy, THz-TDS, THz tomography, X-ray imaging, physical

inspection, authentication, counterfeit detection

1. INTRODUCTION

THz region of electromagnetic spectrum is defined between 300 GHz to 10 THz, and lies in the gap between electronic

and optical signal generation schemes or in other words between microwave and infrared. Many materials in THz

spectral region have unique spectral fingerprints, consequently, THz techniques can be used for determining the

materials in wide variety of objects from medicines to electronic components 1. THz able penetrates many

nonconductive materials and thus it provides a very promising tool for inspection purposes. Consequently, one of the

most promising applications for THz can be considered as material inspection in general and characterizing electronic

components in particular. THz techniques have several advantages over other inspection and characterization techniques.

THz radiation is non-ionizing and thus not only safer for human in compare to ionizing techniques like X-ray or gamma

inspections but also nondestructive for electronic components. In general, compared to other techniques, THz inspection

techniques have the privilege to be nondestructive, nonhazardous, less human dependent and faster.

A current challenge in electronic component market is the identification of counterfeit electronic components.

Counterfeiting and piracy are longstanding problems which are growing in scope and magnitude. They are of great

concern to governments because of (i) the negative impact they have on innovation, (ii) the threat they pose to the

welfare of consumers and (iii) the substantial resources that they channel to criminal networks, organized crime and

other groups that disrupt and corrupt society. They are of concern to business because of the negative impact they have

on (i) sales and licensing, (ii) brand value and firm reputation, and (iii) the ability of firms to benefit from the

breakthroughs they make in developing new products 2. In the world of electronics, the R&D costs for the semiconductor

industry are indeed extremely high, and protection of the IP rights is of utmost importance. In today’s global economy,

electronics components travel around the world before they make it into a cell phone, computer, automotive, military, or

security system. This global market has greatly reduced the cost of electronics, as large foundries and assemblies can

offer lower prices. However, there is another illicit market willing to undercut the competition with equally illicit parts.

If one of these ends up in consumer products, it will likely go undetected. The part may fail prematurely or

unexpectedly, and the manufacturer will simply label the product as a defective unit and likely replace the product under

warranty. However, if these parts end up in critical applications such as defense, aerospace, automotive, or medical, the

results could be catastrophic. This is the market of counterfeits and it is stirring up serious problems in many sectors 3.

Just how big the market is remains a mystery still. A study conducted from 2005 - 2007 reveals that 50% of original

component manufacturers (OCM) and 55% of distributors (authorized and unauthorized) have encountered counterfeit

parts 4. The Electronic Resellers Association International (ERAI)

5 monitors, investigates, and reports issues that are

affecting the global supply chain of electronics. ERAI, in combination with Information Handling Services Inc. (IHS) 6,

has been monitoring and reporting counterfeit component statistics dating back to 2001. They have reported that

counterfeit ICs are impacting $169B electronics systems industry. The steady increase in reported incidents reflects the

need for effective methods of testing parts and maintaining proper records as parts travel through the supply chain.

Without a doubt, counterfeiting of integrated circuits has become a major challenge due to the deficiencies in the

existing test solutions. Towards this goal, THz techniques are to be added to the conventional inspection methods. The

experiments which are reported in this paper prove THz techniques as a promising approach for distinguishing authentic

electronic components from counterfeit ones.

In this paper, high-speed terahertz spectrometer with laser pulse duration of 90 fs and repetition rate of 250 MHz with

measurement frequencies up to 3 THz is used to identify conclusively authentic and counterfeit electronic components.

Time delays, refractive indices and absorption characteristics are extracted. Spot measurements are correlated to THz

imaging of the whole surface of the IC. It is observed that the packaging of counterfeit ICs, as compared to their

authentic counterparts, made from inhomogeneous materials. THz techniques allow the identification of different layers

of the electronic components enabling the die and lead geometries to be inspected; a considerable difference between the

geometries of the dies/leads of the counterfeit ICs and their authentic counterparts are observed. Identification of the

different layers made it possible to distinguish blacktopped counterfeit ICs within a few seconds. All the above

mentioned inspections are nondestructive, not hazardous and fast.

The paper is organized as follows. In Section-II a quick overview on different classes of counterfeit electronic

components are presented along with the ability of the THz techniques for distinguishing of each class. In section-III,

time domain THz techniques are discussed. Different experiments are developed for distinguishing the different classes

of the counterfeit electronic components. Moreover in this section, measurements in broadband THz frequencies for

characterizations of electronic components are discussed. In Section-IV, capabilities of THz systems for producing

tomography images are discussed and used for electronic components characterization/ authentication. Section V

concludes the paper and gives insights for future works.

2. CLASSIFICATION OF COUNTERFEIT ELECTRONIC COMPONENTS

Counterfeit electronic components are classified to 1) unauthorized copies made by the original manufacturer but outside

the transparent contracts. As an example of the aftermath problems made by this counterfeit class, it can be considered

that components with conventional robustness may be introduced as industry/ healthcare level to the market and thus

early failures in industrial/ healthcare plants may cause catastrophic economical and life disasters; 2) off specification,

defective components and the ones that do are not meet the performance standards which should have been put out in

quality control (QC) section but due to errors in QC section or untrustworthy parties in a manufacture, the defective

components have made their way to the market; 3) components with wrong markings or documentation like the

commercial components which may be introduced as the industrial ones for making more profit. The difference between

this class and the first one is the fact that counterfeiters manipulate the marking and documentations of the authentic

components outside a manufacturer to sell them as a more expensive component with higher functionality or reliability

level; 4) the ones that are not produced by the genuine manufacturers. Counterfeiters may have made these ICs with

reverse engineering approaches or just by developing some ICs that make the similar functionalities as the genuine ICs

in normal situations. But early failure and miss-functionalities of these components under different working situations

are expected and these failures can lead to catastrophic industrial and life disasters; 5) previously used components

which are refurbished by unauthorized parties to be sold as new. These components are aged and also the new marks on

them, which are made by the counterfeiters, may refer to another level of their families; early failures are expected for

them. It should be noted that the fourth class, namely unauthorized recycled components, are responsible for the 80% of

reported counterfeit incidents and thus distinguishing them are highly desired 7–10

. In this paper, it is showed that THz

techniques are able to distinguish this class very fast and in non-destructive manners. The counterfeit classifications are

shown in a diagram on Figure 1. In this Figure “C#” refers to the number of the classes that were discussed in this

paragraph.

Recently Guin et al. reported a comprehensive classification of the different counterfeit detection techniques that extends

from visual inspection to X-ray imaging 11

. X-ray imaging, though more accurate, damages the electronic component by

ionizing beam. Other techniques offering more objective characterization of counterfeit components are expensive and

require a considerable amount of time to complete detection, but they are mostly destructive as it is discussed in the next

section. THz as a counterfeit detection technology offers an alternative to the existing technologies by being

nondestructive, conclusive and fast. The results using THz for authentication of electronic components are reported in

this paper for the first time. It is shown that besides class 1 and class 2 counterfeit components, which basically are not

distinguishable by any of the physical inspection tests, all the other classes are distinguishable by THz techniques.

Counterfeit

electronic

components

Made by the

genuine

manufacturer

Made by a

counterfeiter

manufacturer

Refurbished by

counterfeiters:

Previously used

Figure 1. Classification of counterfeit electronic components; the green ticks indicates classes

which are distinguishable by THz techniques

Defective

components

C2

Unauthorized

copies

C1

Unauthorized

refurbished

C5

Unauthorized

copies

C4

Components with

Wrong Marking

C3

3. CHARACTERIZING ELECTRONIC COMPONENTS BY THZ TECHNIQUES IN TIME

DOMAIN

In time domain where the THz pulse passes through a material, attenuation and the time delay in the received THz pulse

are observed, compared to the detected THz pulse passing thorough air. The speed of light is higher in the vacuum than

in materials. The fraction of the speed of light in the vacuum, c , compared to its speed in a material , v , is defined as

refractive index, n :

c

nv

(1)

Most of materials have unique refractive indices and absorption coefficients in THz region 12,13

. Observing different

refractive indices and absorption coefficients for two electronic components implies that the components are made up of

different materials. This fact can be used for authentication of the electronic components.

a) THz techniques in transmission mode

The attenuation and time delay of the received THz pulse can be used as metrics to distinguish if two objects are made

up of the same materials or not. For this purpose the THz machine is set up in transmission mode. The experiment setup

in this technique is shown in Figure 2. The sample is placed between the transmitter and the receiver and the time delay

and the attenuation of the THz pulse is measured compared to the reference signal, where no sample is placed in between

the transmitter and the receiver. The THz signals for eleven different samples and the reference THz pulse are shown in

the same scale in Figure 3(c).

For the case of authentication of the components, observing different indices and absorption coefficients for the two

claimed authentic electronic components of the same production series, makes the claim invalid. In Figure 3(a) four ICs

are shown, two of them are counterfeit and the other two are authentic. Although there are no physical differences

between these ICs, different time delays, and thus different refractive indices, and absorption coefficients are observed

for the counterfeit components compared to those of the authentic ones. This is illustrated in Figure 3(b) and (c). For the

sake of accuracy this experiment has been done for eight authentic and three counterfeit ICs as shown in Figure 3(c). In

this figure the differences between the time delays and absorption coefficients of the authentic ICs and their counterfeit

counterparts are obvious.

As it is indicated on Figure 3(b) absorption for counterfeit ICs are two times of the authentic ones. The time delays of the

counterfeit ICs differ from the authentic ones by 0.22 ps. As it is shown in Figure 3 (c) the time delay of reference THz

pulse, is 29.30 ps while time delays are 35.39 ps for authentic ICs and 35.61 ps for the counterfeit ones. Also the

amplitude of reference THz pulse is 27.75 au while this value is 0.07 au for the case of the authentic ICs and 0.04 au for

the case of counterfeit ones.

The thicknesses of the ICs are measured with a Vernier scale and no sensible difference between the thicknesses of the

authentic and counterfeit ICs are observed. For the sake of accuracy the measured thicknesses are also confirmed with an

X-ray tomography system as 2.30 millimeter.

THz pulse Transmitter

Receiver of the THz pulse

The sample

Figure 2 The experiment setup for transmission mode

(a)

26 28 30 32 34 36 38 40

-1.7

-1.6

-1.5

-1.4

-1.3

-1.2

-1.1

Time Delay [Pico Seconds]

Dete

cto

r C

urr

en

t [a

.u.]

Authentic #1

Authentic #2

Authentic #3

Authentic #4

Authentic #5

Authentic #6

Authentic #7

Authentic #8

Counterfeit# 1

Counterfeit# 2

Counterfeit# 3

Reference (air)

(c)

Figure 3 (a) Four ICs, two of them are counterfeit and the other two are authentic, (b) Time domain inspection

of the ICs which are shown in (a) for four ICs, (c)

(b)

Equation (2) can be used for calculating the refractive index of the ICs in this experiment setup 14

.

1c t

nT

(2)

Where c is the velocity of light, t is the measured time delay and T is the thickness.

By using Equation (3) the attenuation coefficient in units of dB/cm can be calculated 15

.

1020(log ) 8.7e

a a (3)

Where a is called the amplitude attenuation factor and has units in cm-1

and can be calculated by

0

1ln z

a

A

z A (4)

Where 0A is the reference, non-attenuated amplitude of the traveling wave and zA is the actual amplitude of the traveling

wave and it is dependent on the z position of the wave and z is the axis from transmitter to the receiver. Consequently,

the amplitude decay can be modeled as equation (5) and thus z can be substituted by the thickness of the IC.

0az

zA A e

(5)

Substituting the measured values into Equations (2) and Equations (3) gives the refractive index and attenuation

coefficient, for the authentic ICs at 1 THz as 1.79 and 2.263×104 dB/cm respectively. ICs with refractive indices other

than the authentic refractive index can be distinguished as counterfeits. Using Equation (2) and Equations (3), refractive

indices and attenuation coefficients of the counterfeit ICs of Figure 3 are calculated as 1.82 and 2.475×104 dB/cm

respectively. The calculated refractive indices are in the reported range of refractive indices for ceramics16

. This

confirms the validity of the experiment.

b) THz techniques in reflection mode

The different layers of a given component are extracted by using reflection mode THz measurement. The experimental

setup is shown in Figure 4. In the reflection mode, due to the variations in distances from the layers of the sample to the

receiver, the reflected beam arrives at the receiver with variable time delays as seen in Figure 5. In this Figure the two

peaks coincide with the two reflections from the top surface and the interface in between the die and the package

material are observed. This distance can be calculated by Equation (6).

The sample

THz pulse Transmitter Receiver of the THz pulse

Figure 4 The experimental setup in reflection mode. The red laser spot is used to mark the location of the

THz beam

The sample

Receiver of THz pulse Transmitter of the THz pulse

( 1)

2

i i

i

i

td

n

(6)

Where id is the thickness of the layer i , ( 1)i it is the time separations expressed as optical delay in mm and in is the

refractive index of the layer i . The refractive index is calculated by Equation (2) using measurements performed in

transmission mode. In this experimental setup the THz pulse is not perpendicularly emitted to the sample, and thus the

angle of reflection should be taken into account as well. Since the wavelength of THz pulse is small with respect to the

spatial extend of the interface, the reflected and transmitted wave directions will obey the laws of geometric optics.

Consequently, if the THz pulse reaches the surface of the sample by the incident angle,i , then the actual thickness of

the first layer can be calculated using as

121

1

cos2

t

td

n

(7)

Where the transmitted angle,t , is calculated by

1 1

2

sinsin ( )i

t

n

n

(8)

In this experiment 45o

i and thus 23o

t . Substituting these values into Equation (7) gives the thickness of the

layer between the surface and the die as 766 μm which is in consistence with the results of the thickness measurements

by x-ray tomography.

Counterfeiters sand the surface of the recycled ICs to wipe the previously printed marks and then cover the surface with

a black material and reprint new marks on the ICs. They may blacktop new ICs to sell them as higher grade ICs to gain

more profits. One of the highly useful applications for THz techniques in authentication of the electronic components is

distinguishing blacktopped components. Blacktopped counterfeit electronic components have been discussed in many

Figure 5 The transmitted THz pulse in reflection mode experiment setup are received by the

detector with different time delays; X-ray image of the IC from the side and relating the

detected peaks in THz to the different layers detected by X-ray is shown as well.

reports 7,9,18–21

. Unauthorized recycled components are responsible for the 80% of reported counterfeit incidents and thus

distinguishing these counterfeit components is significantly important 7–10

.

Figure 6 depicts the measured THz pulse from a blacktopped IC. In this Figure two reflections with relatively a very

small time separation, compared to the time separation between the die and the surface, are observed. The existence of

the two pulses right after each other implies that a very thin layer is covering the surface of the IC, in other words, the

surface is covered by a blacktopped layer. Using Equation (7) and the refractive index for organic materials from 17

gives

the thickness of the blacktopped layer as 250 μm.

Since the blacktopping materials are transparent to x-ray, x-ray tomography imaging cannot be used for distinguishing

the blacktopped components. Distinguishing the blacktopped components with an optical microscope is possible as

shown in Figure 6(b) but, prior to inspection the surface of the component should usually be exposed solvents, such as

Figure 6 (a) A blacktopped counterfeit IC, (b) Observing the blacktopped

layer by an optical microscope, (c) The THz pulse`s parts in experiment

setup of Figure 5 observed for a blacktopped counterfeit IC.

(a) (b)

(c)

acetone. It has been observed that as counterfeiters are using more advanced techniques, the blacktopped materials may

not be soluble in acetone and thus variety of different chemical agents with extended exposure time up to hours and

heated exposures are needed for distinguishing the blacktopped components. Also it is reported that in some cases even

after 7 days of exposing a blacktopped IC to pure acetone, the blacktopped materials were not detectable and the only

way to distinguish the blacktopped layer was making scratches on the surfaces of the ICs with an X-acto knife 18,19

.

Obviously, unlike THz techniques, all these methods are destructive, highly time consuming and human dependent thus

expensive and not accurate.

Fourier Transform Infrared Spectroscopy (FTIR) and Energy Dispersive X-ray Spectroscopy (EDS) can be used to

distinguish the difference between the materials embedded in the electronic components. Thus, seeing different materials

on the top and sides of a component makes it distinguished as a blacktopped component19

. Still, these methods are more

time consuming than THz technique, needing more analysis by the operator and destructive in case of EDS, since X-ray

is an ionizing radiation 19

.

Scanning electron microscopy (SEM) and scanning acoustic microscopy (SAM) are also used for accurate surface

texture inspection of the electronic components. If the back and top surface are different, then the component can be

distinguished as a blacktopped 18,19

. These methods, compared to THz technique, are highly time consuming and human

dependent thus expensive and not accurate.

C) Broadband terahertz characterization of the refractive index

Variations of refractive indices of materials in different THz frequencies can give a signature to characterize them 16,17

.

In Figure 7 refractive indices of two authentic ICs and their counterfeit one are depicted. Interestingly, the refractive

indices of the authentic ICs are the same in the THz frequency domain while that of the counterfeit one stands out.

In addition to the detection of the counterfeit components, this technique can be used in QC sections of the

manufactures22–24

. For this purpose, observing differences between the confirmed THz spectroscopy patterns of the

components and the produced components implies that the materials of the produced components are other than what

they are supposed to be. Consequently, the presence of air bubbles and/ or unwanted impurities can be distinguished.

1.5 2 2.5 3 3.5 4

0.5

1

1.5

2

2.5

Frequency [THz]

Refr

acti

ve In

dex

Autentic IC #1

Autentic IC #1

Counterfeit IC #1

Figure 7 refractive indices of two authentic ICs and their counterfeit one in THz

frequency domain.

4. CHARACTERIZING ELECTRONIC COMPONENTS BY THZ IMAGING TECHNIQUES

Figure 8 shows THz images in transmission mode and reflection mode experimental setups these images are built by

accumulating the real time absorption and phase measurements on a two dimensional plane. Then the measured values

are depicting by an appropriate color scales.

a) THz imaging techniques in transmission mode

In Figure 9, THz imaging from the authentic and counterfeit ICs are shown. As seen in this Figure, THz images in

transmission mode are formed similar to X-ray imaging where the images are formed based on the attenuation of the x-

ray beam upon reaching the detector. Metals block the THz pulse and thus the materials which are placed behind the die

and leads cannot be observed. Consequently, where no pulse is detected at the detector, die and leads can be considered

to be located. By considering the THz images in Figure 9, two differences between counterfeit ICs and authentic ones, in

terms of the die and leads geometries are distinguishable. (1) The dies in authentic ICs are placed horizontally while in

the counterfeit ones dies are placed vertically. (2) Leads are denser in the left bottom corner of the authentic ICs and thus

an asymmetry is observed for authentic ICs in THz images. Consequently, counterfeit ICs with different die / lead

geometries are distinguishable with THz imaging technique in transmission mode. X-ray can also be used for this

purpose, but THz is not ionizing and thus it is not destructive for electronic components and it needs less safety

regulations for the operators as well.

Figure 8 (a) THz image of an IC of Figure 4, The left image is obtained in reflection

mode and the right one in transmission mode. (b) Color scale for TH images and the x-

ray image of the IC (c) X-ray and THz images are superimposed.

(a)

(b)

(c)

b) THz imaging techniques in reflection mode

The experiment setup in reflection mode is shown in Figure 4. As discussed in section 3-b and shown in Figure 7, the

portions of the THz pulse which are reflected from different layers reaches the detector in different time delays, and thus

obtaining the THz images of different layers of the electronic components is possible. A tomogram is an image of a

plane or slice within an object 15

. In Figure 10 images of the different layers of an IC obtained by THz techniques are

shown. According to the definition of tomogram, images in Figure 10 can be called tomograms.

Inspection of die and leads geometries can be considered as applications of this technique. Moreover, inspection of the

surface of the IC can be done using this technique. Figure 11 depicts THz images from the surfaces of a counterfeit IC

and its authentic counterpart. It is observed that the packaging of counterfeit ICs are not made from homogeneous

materials. In Figure 11 (b) existences of foreign materials, with different reflection characteristics, are obvious on the left

top part of the counterfeit IC. Also the image of the whole surface of the counterfeit IC is not as smooth as that of the

authentic one. In particular, it is observed that the variance of the reflected THz from the surface of the counterfeit IC is

2.70 au while that of the authentic one is 1.17 au which is less than 45% of that of the counterfeit IC. Also, the difference

between the peak and the minimum value of the surface is 0.076 au for the counterfeit IC while it is 0.061 au for the

Figure 9 (a) THz image of one of the authentic ICs of Figure 3(a) and its x-ray counterpart. (b) THz image

of one of the counterfeit ICs of Figure 3(a) and its X-ray counterpart. (c) Color scale for the THz images.

Asymmetry

(b)

(a)

(c)

Vertical die

Asymmetry

Horizontal die

authentic IC, in other words the difference between the peak and the minimum value of the surface of the counterfeit IC

is 25% higher than that of the authentic one.

Figure 10 (a) THz image of the surface of one of the ICs of Figure 3(a) in reflection mode.

(b) THz image of the die of the IC. (c) THz image of the leads of the IC, obtained in

reflection mode. (d) The color scale.

(a) (b)

(c)

(d)

Figure 11 (a) THz image of the surface of one of the authentic ICs of Figure 3(a), (b) THz image of the surface

of one of the counterfeit ICs of Figure 3(a)

(a) (b)

5. CONCLUSIONS

THz pulse lasers have not been commercially available until only two decades ago and thus THz techniques need to be

developed for different aspects of science and engineering. One of the highly promising fields for THz techniques is

characterization and inspection of electronic components. Other techniques are mostly destructive, time consuming,

hazardous to personnel, human dependent and thus expensive and with higher errors, while THz is nondestructive, fast,

safe for personnel and accurate.

It was also showed that, a wide variety of counterfeit electronic components are also distinguishable with THz

techniques. Due to high benefits, counterfeiters are continually making their counterfeiting techniques more

sophisticated. It becomes more and more difficult to distinguish authentic components from the counterfeit ones. More

and more counterfeit electronic components are injected to the global market as well. Consequently, new authentication

techniques should be developed day by day to distinguish counterfeit components. As discussed in this paper THz

techniques are fast, economically reasonable, reliable, accessible for wide variety of consumers, nonhazardous and

nondestructive. Obtaining the refractive index and absorption coefficient of each of the electronic components by THz

techniques makes it possible to distinguish between the authentic components and their counterfeit counterparts. In this

work different refractive indices and absorption coefficients were observed for counterfeit components compared to their

authentic counterparts. By developing THz techniques distances of the leads and die from the surface of the integrated

circuits (IC) were calculated. The calculated values were confirmed by the results obtained from the X-ray images.

Moreover, blacktopped counterfeit electronic components were distinguished by THz techniques. It is notable that

blacktopped counterfeit components are not distinguishable by X-ray imaging. Moreover, conventional techniques for

distinguishing blacktopped components are time consuming, random, destructive and hazardous for personnel.

Capabilities of THz systems for producing tomography images were also discussed. In this work by THz imaging

techniques, counterfeit ICs with die and lead dislocations were detected. In addition, in THz images from the surfaces of

the ICs presence of foreign materials on the surfaces of the counterfeit components was observed.

REFERENCES

[1] Kawase, K., Ogawa, Y., Watanabe, Y.., Inoue, H., “Non-destructive terahertz imaging of illicit drugs using

spectral fingerprints,” Opt. Express 11(20), 2549 (2003).

[2] Http://www.oecd.org/dataoecd/13/12/38707619.pdf., “‘OECD, The Economic Impact of Counterfeiting and

Piracy,’.”

[3] Congress, U. S., “Ike Skelton National Defense Authorization Act for Fiscal Year 2011,”

<http://www.gpo.gov/fdsys/pkg/BILLS-111hr6523enr/pdf/BILLS-111hr6523enr.pdf>.

[4] “Defense Industrial Base Assessment: Counterfeit Electronics.”, (2010).

[5] “Electronic Resellers Association International (ERAI).”, <http://www.erai.com/.>.

[6] “Information Handling Services Inc. (IHS).”, < http://www.ihs.com/>.

[7] Guin, U., Huang, K., DiMase, D., Carulli, J. M., Tehranipoor, M.., Makris, Y., “Counterfeit Integrated Circuits:

A Rising Threat in the Global Semiconductor Supply Chain,” Proc. IEEE 102(8), 1207–1228 (2014).

[8] Hewett, H. W.., Services, E., “METHODS USED IN THE DETECTION OF COUNTERFEIT ELECTRONIC

COMPONENTS,” SMTA Int. Conf. (2010).

[9] Caswell, G.., Place, R., “Counterfeit Detection Strategies : When to Do It / How to Do It By :,” ISTFA 2012

Conf. Proc. from 38th Int. Symp. Test. Fail. Anal. (2012).

[10] Guin, U., Forte, D.., Tehranipoor, M., “Anti-counterfeit Techniques: From Design to Resign,” 2013 14th Int.

Work. Microprocess. Test Verif.(ii), 89–94 (2013).

[11] Guin, U., Huang, K., DiMase, D., Carulli, J. M., Tehranipoor, M.., Makris, Y., “Counterfeit Integrated Circuits:

A Rising Threat in the Global Semiconductor Supply Chain,” Proc. IEEE 102(8), 1207–1228 (2014).

[12] Chan, W. L., Deibel, J.., Mittleman, D. M., “Imaging with terahertz radiation,” Reports Prog. Phys. 70(8), 1325–

1379 (2007).

[13] Jin, Y., Kim, G.., Jeon, S., “Terahertz Dielectric Properties of Polymers,” J. Korean Phys. Soc. 49(2), 513–517

(2006).

[14] Theuer, M., Beigang, R.., Grischkowsky, D., “Highly sensitive terahertz measurement of layer thickness using a

two-cylinder waveguide sensor,” Appl. Phys. Lett. 97, 96–98 (2010).

[15] Prince, J. L., Medical imaging signals and systems, Pearson Prentice Hall, Upper Saddle River, NJ (2006).

[16] Naftaly, M.., Leist, J., “Investigation of optical and structural properties of ceramic boron nitride by terahertz

time-domain spectroscopy.,” Appl. Opt. 52, B20–5 (2013).

[17] Cunningham, P. D., Valdes, N. N., Vallejo, F. a., Hayden, L. M., Polishak, B., Zhou, X. H., Luo, J., Jen, A. K.

Y., Williams, J. C., et al., “Broadband terahertz characterization of the refractive index and absorption of some

important polymeric and organic electro-optic materials,” J. Appl. Phys. 109 (2011).

[18] Hughitt, B., “Counterfeit Electronic Parts” (2010).

[19] Radman, J. M.., Phillips, D. D., “Novel Approaches for the Detection of Counterfeit Electronic Components,”

Compliance Mag.(October) (2010).

[20] Guin, U., Tehranipoor, M., Dimase, D., Development, S.., Megrdichian, M., “Counterfeit IC Detection and

Challenges Ahead” (2015).

[21] “Counterfeit Examples Electronic Components: Counterfeit Components Avoidance Program CCAP-101

Certified * Appendix A-6, Rev. E.”, (2013).

[22] Scheller, M., Jansen, C.., Koch, M., “Analyzing sub-100-um samples with transmission terahertz time domain

spectroscopy,” Opt. Commun. 282(7), 1304–1306, Elsevier B.V. (2009).

[23] Wietzke, S., Jansen, C., Rutz, F., Mittleman, D. M.., Koch, M., “Determination of additive content in polymeric

compounds with terahertz time-domain spectroscopy,” Polym. Test. 26, 614–618 (2007).

[24] Stoik, C. D., Bohn, M. J.., Blackshire, J. L., “Nondestructive evaluation of aircraft composites using terahertz

time domain spectroscopy.,” Opt. Express 16 (2008).