1

Three Dimensional Modeling and Characterization

for Die Attach Process

Lin Bu, Wai Leong Ching, Ho Siow Ling, Minwoo Rhee, Yong Puay Fen

1

Abstract: A new three dimensional model for the die

attach (DA) process is established and validated in the

present study. With this model, the fluid flow

characteristics of the DA process can be predicted

accurately. Dynamic mesh and interface tracking method

were adopted in the modeling to study the compression

motion and the front of DA. Force driven model was

conducted for the parametric studies of different bonding

force. The model for the DA process was validated by the

four materials, AP1, CA1, CA4 and DM60 in the

optimized condition. Bond line thickness (BLT) can be

predicted by simulation with ~20% accuracy. The

simulation results show that viscosity is one of the key

properties, which has a significant effect on the required

bonding force, bonding time and DA contamination on the

die top. Complete filling and DA contamination on the die

top are two important standards to evaluate the good

bonding force range in fluid dynamic analysis. Stress

analysis illuminates that fillet area is very critical and

experiences highest stress during the reflow process.

Index Terms — die attach process, bond line thickness

(BLT), bonding force

I. INTRODUCTION

ie attach provides the mechanical support between the

silicon die and the substrate, i.e,. leadframe, plastic or

ceramic substrate. The die attach is also critical to the

thermal and, for some applications, the electrical performance

of the device. Significant results have been achieved in

previous studies, focusing on mechanical analysis for the DA

process. Dynamic mechanical analysis (DMA) was employed

to characterize the modulus behavior of silver filled glass

material. The method used a simulated DA process to

understand the behavior of the storage modulus and the

complex viscosity [1]. DMA taking into account multi-step

curing was utilized to determine gelation times and melt

viscosity under a shear mode by Taweeplengsangsuke J. [2].

They found that the longer the period of time at the lower

temperature step of the 2-step curing gave rise to lower cure

stress. In addition, the stress during the cool down process was

investigated. At the point of decreasing temperature, the stress

dramatically increases. The higher temperature difference, the

larger the residual stress. Xiaosong M. et al. [3] developed a

finite element model to predict the interface delamination

1The authors are with the Institute of Microelectronics, Agency for

Science, Technology and Research, 117685, Singapore.

Corresponding author is Min Woo Rhee. (e-mail: bul@ime.a-

star.edu.sg; wailc@ime.a-star.edu.sg; hosl@ime.a-star.edu.sg;

mw.daniel.lee@gmail.com, sherylyong@ntu.edu.sg).

issues encountered in the DA process. It is found that

temperature has a large effect on the interface toughness (Gc).

Gc greatly decreases with increasing temperature. In addition,

moisture has no effects on interface toughness of copper and

silver filled DA in their samples. Khoo Ly Hoon [4] et al.

aimed to establish a robust DA process by evaluating various

responses on DA epoxy with various values of epoxy

viscosity. The findings of their study reveal that the epoxy

viscosity within the tested range does not significantly affect

DA and wire bond performance. Nicolas Heuck et al.[5]

investigated the impact of the CTE of die-attach layers on the

thermal stress in chip and attach layer, along with strategies to

reduce the CTE of conventional silver sintered die-attach

structures by adding materials like SiC or h-BN. They found,

that the implementation of SiC and especially of h-BN

additives in 200μm thick sintered silver die-attach layers can

lead to a stress reduction up to 30%.

However, rheological simulations that can investigate the

flow of the liquid DA under an applied force during the DA

process are rare. In order to enhance the evenness of epoxy

distribution along the peripheral of the die, Mark Lee [6] built

a 2D model to investigate various dispensing patterns and to

study their evolvement patterns. The thin-film assumption is

used in the simulations. The studies shows that a suitable

epoxy pattern is the key to ensure that the epoxy dispensed on

the substrate can evolve to the final shape of the chip after the

initial squeezing during the DA process. Complex dispensing

patterns, i.e. snow star pattern are more likely to trap voids

than basic dispensing pattern, i.e. x dispensing pattern.

However, 2D simulation cannot capture the 3D real process

very well and many important properties like surface tension

and contact angle are not incorporated into the model.

Important information such as BLT and contaminations on the

die top in the DA process could not be obtained due to 2D

constraint. The prediction of final BLT and die top

contaminations are as important as epoxy dispensing patterns.

Final BLT would have a significant effect on the reliability of

the whole system. Man Wai Chan [7] et al. invented a way to

measure BLT with laser equipment. They can also control

BLT in a desired range by adjusting the four parameters, 1)

adhesive dispensing pressure of the dispenser, 2) bond level of

the bonding tool, 3) bond force exerted by the bonding tool

and 4) bond delay of the bonding tool.

In the present study, rheological simulations were carried

out using the three dimensional model. Surface tension model

and wall adhesion model are enabled to take into account the

effect of surface tension along the interface of two fluids and

the contact angle that the fluid makes with the wall.

Appropriate bonding force and BLT ranges for the

optimization of DA process can also be predicted by the

present model.

D

2

II. PACKAGE DESCRIPTION AND CRITICAL ISSUES

DURING DA PROCESS

Institute of Microelectronics at A*STAR Singapore and its

industry partners have developed a DA technology, based on a

5×5 mm2 top chip. Fig. 1 demonstrates a schematic plot of DA

process.

Fig. 1. Schematic plot of DA process

The DA process consists of three stages. First stage is to

dispense an adhesive with a dispenser onto the substrate.

Then, in the second stage, a semiconductor die is picked and

placed on the adhesive which has been dispensed onto the

substrate with a bonding tool with vacuum. Thereafter, in the

third stage BLT between the bottom surface of the

semiconductor die and top surface of substrate on the process

platform using a measuring device.

(a) Overflow

(b) Incomplete fill

Fig. 2. Schematic plot of DA issues. (a) Overflow. (b) Incomplete fill.

During the second stage, void issue, bad fillet and

contamination on the die top are the key issues. Epoxy

climbing along the edge of the die will lead to the formation of

DA fillet. Excessive DA fillet can lead to DA contamination

of the die surface. Too little of it may lead to die lifting and

die cracking. These two issues are demonstrated in Fig.2.

Voids maybe trapped by using inappropriate dispensing

patterns. Voids in the epoxy not only increase thermal and

electrical resistance, but also trigger electrical breakdown at

extreme conditions. Overcoming these three issues is a

balance of controlling dispensing pattern, bonding force and

bonding time.

III. GOVERNING EQUATIONS

The equation for the conservation of mass, or continuity

equation, shared by the two phases, can be written as follows

[8],

( ) (1)

Conservation of momentum in an inertial (non-accelerating)

reference frame, also shared by the two phases, is described

by,

( ) ( ) ( ) (2)

Where p is the static pressure, is the stress tensor, and

is the gravitational body. represent the surface tension

force by CSF (continuum surface force) model provided by Brackbill

et al, [9].

The energy conservation equation, still shared by the two

phases, is as follows,

( ) ( ( )) ( ) (3)

The VOF model treats energy, h, and temperature, T, as

mass-averaged variables. The properties and keff (effective

thermal conductivity) are shared by the phases.

The compressible fluid complies the idea gas law,

(4)

The transport equation is determined by,

( )

( ) (5)

{

The properties appearing in the transport are determined by

the presence of the component phases in each control volume.

In a two-phase system, if the phases are represented by the

subscripts l and g, the density in each cell is given by,

( ) (6)

IV. MATERIAL CHARACTERIZATION

A. Viscosity measurement and characterization

Viscosity is one of the key properties which will have a

significant effect on the finial BLT and bonding time. Power

law was used to characterize the viscosity of epoxy, as shown

in equation (7):

μ=γ1-n

(7)

Where and n are input parameters. is a measure of the

average viscosity of the fluid (the consistency index); n is a

measure of the deviation of the fluid from Newtonian (the

power-law index). The value of n determines the class of the

fluid (i.e. Newtonian fluid, dilatants fluids or pseudo plastics).

The time dependent viscosity is measured by the fluid

viscometer. In the non-Newtonian phenomenon, viscosity

deceases with share rate for four corresponding materials, as

shown in Fig.3. Subsequently, the measurement results are

Pick up tool

Substrate

DA

Top chip

3

characterized with power law trend line. and n are finally

determined and put into software for modeling setup. In the

experiment, the shear rate is from 1-100 1/s at room

temperature. In the simulation, we also set up the min. and

max viscosity according to the experiment. In the very low

shear rate region, we redeem the material as shear rate

independent.

Fig. 3. Viscosity measurement results

B. Contact angle measurement

A contact angle can be measured by producing a drop of

liquid on a solid. The angle formed between the solid/liquid

interface and the liquid/vapor interface is referred to as the

contact angle. The most common method for measurement

involves looking at the profile of the drop and measuring two-

dimensionally the angle formed between the solid and the drop

profile with the vertex at the three-phase line as shown in Fig.

4 and table 1. Young's equation is used to describe the

interactions between the forces of cohesion and adhesion and

measure what is referred to as surface energy. Due to epoxy is

not an isotropic medium, the measurement results were

collected from different directions. The averaged contact angle

for different materials is imported into software as the

modeling input. Fig.5 lists the average contact angle for the

different combination of three epoxies and two material

metallization. Hydrophilic angles (<40˚) were observed for all

the alliances, which ensures qualified wetting and adhesive for

the DA procedure.

Fig. 4. Contact angle measurement result

Table 1 Contact angle measurement result

Unit R L

CA1 (SiN) 1 24.5o

26.5o

2 25o

27o

DM60 (SiN) 1 13o

13o

2 10o

23o

AP1 (SiN) 1 24.5o

25.5o

2 18o

24o

AP1 (Si-Ag) 1 48o

33o

2 29o

30o

Fig. 5. Average contact angle

V. MODELING

In order to further understand the DA process,

computational fluid dynamics (CFD) simulation is a valuable

tool. However, establishing a validated model is a challenging

task. In this paper, a 3D finite volume model was established,

as shown in Fig. 6. The evolution of the epoxy front is tracked

by the Volume of Fluid (VOF) [10] method. The modeling

consists of the following assumptions:

1. Quater model is adopted to save computation efforts.

2. In the experiment as well in the simulation, there are two

ways of controlling the travel of the die. (1) Velocity

controlling: with velocity and time controlling, the

ultimate overtravel length and final BLT could be

determined. (2) Force controlling: force controlling can’t

determine the overtravel length at the initial time. Final

BLT depended on the balance of the applied bonding

force, gravity force and surface tension force.

3. Bonding force could be applied by user defined functions

(UDF). With impropriate bonding force profile, mesh

collapse will be easily encountered.

4. The curing of the DA material is not considered.

y = 4.4011x-1.025

y = 87.144x-0.616

y = 10.069x-0.86

y = 2.1507x-0.651

0.01

0.1

1

10

100

1.00 10.00 100.00

Vis

cosi

ty (

Pas

)

Shear rate (1/s)

AP1

CA4

CA1

DM60

0

5

10

15

20

25

30

35

40

CA1 on SiN DM60 onSiN

AP1 on SiN AP1 on Ag

Ave

rage

co

nta

ct a

ngl

e (

°C)

4

(a)

(b)

Fig. 6. 3D modeling of DA process. (a) x dispensing pattern. (b) Boomerang

dispensing pattern

VI. VALIDATION

The model for the DA process was validated for the four

materials in the optimized condition. The experiments and the

simulation data matched very well, as shown in Table 2. The

four materials with different properties and different bonding

forces proved the feasibility of the model in a wide range.

BLT can be predicted by the simulation with less than 20%

errors. Table 2 Comparison of BLT between experiment and modeling

Input parameters (temperature fixed as 25°C)

Results

Material

Density

Dispensing weight

Bonding force

Dispensing

pattern

Experiment

Modeling

CA4 6g/cm3 4.6mg 60g x 28.5m 24.7m

CA1 4.4g/c

m3

4.33mg 28g x 28.5m 26.7m

DM60

4.5 g/cm3

2.98mg 21.75g x 28.87m 21.5m

AP1 4.2229g/cm3

4.43mg 43.5g

Boomerang

32.5m 31.7m

In order to further validate the model, the visual inspected

die attach final filler shape was examined at two locations

shown in Fig.7. Fig.8 shows the validation results through

modeling and experiment for material CA4, CA1, DM60 and

AP1. The contaminations at location 1 for the four cases show

the prediction results are in good accordance with the

experiment. A concaved feature was perceived at location 2 by

using material AP1 with boomerang dispensing pattern. This

phenomenon is captured in experiment as well as the

simulation result, as shown in Fig.8 (d). For the other cases,

the model using x dispensing pattern, the filler shape is

comparatively straight.

Fig. 7. Inspected locations

(a)

(b)

(c)

5

(d)

Fig. 8. Validation results through modeling and experiment. (a)CA4.(b)CA1.

(c)DM60. (d)AP1

VII. RESULTS AND DISCUSSION

A. Effect of dispensing pattern

Dispensing pattern is very important during the die attach

process. The key difficulty is that the square shape of the die is

not easy for full filling. There are four criterions to judge a

proper dispensing pattern: (1) even and strong fillet; (2) little

or no contamination on die top; (3) high coverage.

In experiment, x dispensing pattern (A) and star dispensing

pattern (B&C) with material CA1, was tried first to observe

the coverage and the fillet, as shown in Fig.9. Dispensing B &

C was observed heavy wavy fillet coverage. After curing, the

fillet will has some shrinkage. Dispensing pattern A was

decided to use to do further work. In the simulation, the results

should have a strong fillet due to curing was not included in

the simulation.

Fig.9 Experimental results of x and star dispensing pattern

Excess materials were observed at four corners at the die for

dispensing pattern A with an overtravel length of 50um.

Simulation was conducted in the meanwhile to confirm this

phenomenon.

Fig.10 reveals the transient histories of the DA melting

front with an x dispensing pattern. At the initial state, as

shown in Fig.10 (a), the DA material was dispensed like an

“x” shape. As the time went on, the melting front evolved

from the central to the peripheral of the chip. Ultimately, as

shown in Fig.10 (d), DA material fully filled the chip.

(a)

(b)

(c)

(d)

Fig. 10. Time dependent simulation results for CA1.(a) t=0ms. (b) t=40ms. (c) t=70ms. (d) t=80ms.

Fig. 11. Comparison of experiment and simulation with x dispensing pattern

6

Once the simulation was validated by the experiment, as

shown in Fig.11. Further investigation should be done to

improve the process.

Fig.12 Three parameters for optimization

Three parameters, A, W and D, could be optimized regarding

to x dispensing pattern in the simulation, as shown in Fig.12.

After a series of simulation have been done, A/W/D was

finalized as 7.11mm/1.23mm/0.386mm, as shown in Fig.13.

Fig.13 x pattern before and after optimization

For material CA1, CA4, DM60, both experiment and

simulation shows good coverage with x dispensing pattern.

The x-ray image after die attach with full material coverage

was also shown in literature [11].

For material AP1, incomplete epoxy coverage at 1/3 length

from corner was detected from x-ray image. Thus, boomerang

dispensing pattern was used to meet the coverage requirement.

Fig. 14 shows the transient histories of the DA melting front

with a boomerang dispensing pattern in simulation. Four

additional volumes of DA that resemble “v” shape were added

to the edge of the substrate in order to get a full coverage, as

shown in Fig. 14 (a). The edge of the additional volume and

“x” was joined as the time went on and moved together

towards the edge of the top chip, as shown in Fig. 14 (d). Full

coverage was achieved and the revised pattern is sufficient to

meet the target. At the joint part of “v” and “x”, a concaved

feature could be observed.

(a)

(b)

(c)

(d)

Fig. 14. Time dependent simulation results for AP1. (a) t=0ms. (b) t=2ms. (c)

t=3.3ms. (d) t=6.5ms.

Boomerang dispensing pattern found slight void in the

simulation results, which is less than 1%. However, in the real

case, the migration of metal induced porosity is much higher

than the process induced porosity [11], as shown in Fig.15.

Fig.15. Porosity of AP1 material [11]

7

The Scanning Electron Microscope(SEM) image was shot

at different cross sections. With 5mm×5mm die size, the

porosity in some area is larger than 10%.

Fig.16. Cross section image from experiment [11]

Table 3 Fillet height and BLT in the experiment

Fillet

Height

(L)

Fillet

Width

(L)

BLT (L) Fillet

height

%(L)

BLT (R) Fillet

height (R) Fillet

Width

%(R) 64um 138um 33um 62% 36.5u

m 62um 51%

111um 135um 27.5um 47% 23um 130um 61%

Fig.16 reveals the cross section result for two different die

thicknesses, i.e., 50um and 175um. No voids or delamination

was perceived during the experiment. The fillet height ratio

ranges from 47%-62%. In simulation, the most critical area

with low fillet occurs at the central of the die edge for x

dispensing pattern. However, the low fillet area appears at 1/3

length from die corner for boomerang dispensing pattern.

In literature [12], fillet height range from 0%-75% was

studied, 0% fillet height was observed with the worst

delamination. For the fillet height above 0%, higher fillet is

generally having more delamination after TC and MSL test.

Some delamination was found at 75% fillet height. In our

reliability test, only very low fillet has the delamination issue.

Fig.17 shows the delamination at die edge with 1000 hours

high temperature storage (HTS) test with DA material AP1.

The cross section image at center of the package was taken

after HTS test, the fillet height could be deducted that it was

also not good at 0 time. Fig.18 revealed some delamination

between underfill and leadframe with DA material DM60 after

MSL3 test. The fillet was also in the worst condition, near 0

fillet.

Fig.17 DA delamination at DA fillet area after HTS1000

Fig.18 Delamination between underfill and leadframe after MSL3 test

B. Fluid analysis with force control

(a)

(b)

Fig.19. Effect of bonding force in the DA process. (a) Bonding force window with fluid analysis. (b) BLT range for good DA.

From the simulation results, the bonding force process

window was extracted to provide the process optimization.

Fig.19 (a) displays the relationship between the DA coverage

on die top and substrate vs. bonding force for AP1 in the

optimized condition. It can be seen that complete filling was

obtained when the bonding force range falls above 10g. The

DA contamination on the die top was always above 0%.

Fig.19 (b) illustrates the corresponding BLT range at different

bonding force. As the bonding force increase, DA

contamination on the die top and DA coverage on the

substrate will increase along with it. However, increasing of

0.0%

0.1%

0.2%

0.3%

0.4%

0.5%

80%

85%

90%

95%

100%

0 10 20 30 40 50 60 70 80 90

DA

co

vera

ge o

n d

ie t

op

DA

co

vera

ge o

n s

ub

stra

te

Bonding force /g

0

20

40

60

80

30 32 34 36

Bo

nd

ing

forc

e /

g

BLT /um

8

bonding force will lead to decreasing of BLT. With force

control of very thin die as 50um, contamination on the die top

is hard to control. Thus, position control was used to make a

good fillet height [11].

C. Stress analysis for DA process

Fig.20 Stress (MPa) variation along the edge of the DA at DA BLT equals to

10um, 20um, 30um and 40um.

Investigating the stress level at the DA in the vicinity of the

edge of the DA, it can be observed that stress increases

towards the corner of the DA for all the thicknesses

investigated. It is evident that the die attach fillet area is most

critical, as shown in Fig.20. In this area, silicon die, die attach

material, substrate and backside metallization are

concentrated. Highest CTE (coefficient of thermal expansion)

mismatches are experienced during the die attach process and

later on molding and reflow process. In the reliability test, like

HTS (high temperature storage), TC(thermal cycling), die

edge area has high possibility leading to failure. During MSL

reliability test, the edge area also experiences the highest CME

(coefficient of moisture expansion) mismatch as well.

Also, it is obvious that increasing the thickness of the DA

material is favorable in reducing the amount of DA stress in

the package. Although the DA candidates investigated

comprised mainly of silver sintering material, the metallic DA

is more compliant as compared to silicon and leadframe and

increasing its thickness will help to introduce more

compliance thereby reducing DA stress. Mechanical

simulations suggest that a higher BLT is more desirable in

reducing the DA stress.

The detailed process dependent modeling was elaborated in

[13]. Four process steps are simulated, namely, die attach

process at 25ºC, molding process at 175ºC, cooling down to

room temperature at 25ºC and reflow process at 260ºC. The

most critical process is reflow process, which leads to the

highest stress in die attach material.

VIII. CONCLUSION

The 3D DA numerical simulation has the advantage of

giving a deep insight into the DA flow mechanism. Some

important conclusions and recommendations from this paper

can be summarized as follows.

(1) Amongst all the material properties, viscosity is one of the

dominant factors in the DA process. It has a significant

effect on the required bonding force, bonding time and

DA contamination on the die top. Most of the time, the

material property is temperature dependent. The viscosity

of the DA material could be adjusted by pre-heat of the

substrate.

(2) Two kind of dispensing patterns were considered in the

modeling, i.e. x dispensing pattern and boomerang

dispensing pattern. Two patterns are used for different

materials. For material CA1,CA4, DM60, no abnormity

was observed during the experiment. Boomerang

dispensing pattern was used to solve the incomplete fill

issues encountered for material AP1.

(3) With ultra-thin die as 50um, force control is very hard to

control the final fillet height and contamination on the die

top. Position control is more favorable in controlling the

two.

(4) For x dispensing pattern, simulation shows that in the

central of die edge, low fillet has higher possibility to

occur. The most dangerous/low fillet location could be

changed to 1/3 length from die corner for boomerang

dispensing pattern.

(5) Fillet area is the most critical area in the die attach

process. Highest CTE and CME mismatches are

experienced during the die attach process and later on

molding and reflow process. In the reliability test, die

edge area has high possibility leading to failure.

(6) Mechanical simulations suggest that a higher BLT is more

desirable in reducing the die attach stress. The highest

stress appears at reflow temperature.

ACKNOWLEDGMENTS

This work has been carried out as part of the 11th

Electronics Packaging Research Consortium (EPRC-11) led

by the Institute of Microelectronics (IME), a research institute

of the Agency for Science, Technology and Research

(A*STAR). The members of the consortium include

GLOBAL FOUNDRIES, HERAEUS, INFINEON Co. Ltd.,

NXP Pte Ltd, OPTITUNE Pte Ltd, and ROLLS-ROYCE Pte

Ltd. The authors are grateful to members of EPRC 11 –

EMWLP Project as well as IME staffs who had contributed

and made this work possible.

REFERENCES

[1] Trirat Hongsmatip. “Dynamic Mechanical Analysis of

Silver/Glass Die Attach Material,” Electronic

Components and Technology Conference, pp.692-700,

1995.

[2] J. Taweeplengsangsuke, J.C. Hsiung, and R.A. “Modeling

the Die Attach Adhesive Process,” International

symposium on advanced packaging materials, pp. 165-

169, 1998.

[3] Xiaosong Ma, G.Q. Zhang and O. van der Sluis, et al.

“Die Attach Interface Property Characterization as

Function of Temperature using Cohesive Zone Modeling

9

Method,” 11th. Int. conf. on Thermal, Mechanical and

Multiphysics Simulation and Experiments in Micro-

Electronics and Micro-Systems, pp. 1-8, 2010.

[4] Khoo Ly Hoon, Au Yin Kheng. “In-Depth

Characterization of Die Attach Adhesive for Low-K

Automotive Device Application,” 11th Electronics

Packaging Technology Conference, pp. 977-981, 2009.

[5] Nicolas Heuck, Armin Langer and Andrej Stranz, et al.

“Analysis and Modeling of Thermomechanically

Improved Silver-Sintered Die-Attach Layers Modified by

Additives,” IEEE transactions on compounents,

packaging and manufacturing technology, Vol. 1, pp.

1846-1855, 2011.

[6] Mark Lee, “The Squeezing Process of Complex Epoxy

Patterns in the Die-attaching of Large IC-Chip,”

International Conference on Electronic Materials and

Packaging, pp.1-8, 2006.

[7] Man Wai Chan, Shiu Kei Lam, Wan Yin Yau, Kwok

Yuen Cheung, Bond Line Thickness Control for Die

Attachment,” Patent US20130011941 A1, 2013

[8] Rohsenow W. M., Hartnett J.P., Garnic E.N., “Handbook

of Heat Transfer Fundamentals”. 2nd ed. New York:

McGraw-Hill, 1985

[9] J.U.Brackbill, D.B.Kothe, C. Zemach., “A continuum

method for moeling surface tension.” J.Comp..Phys., Vol

100, pp. 335-354, 1992.

[10] C. W. Hirt, B. D. Nichols, “Volume of Fluid (VOF)

Method for the Dynamics of Free Boundaries,” J. Comp.

Phys., Vol.39, pp. 201–225, 1981.

[11] Leong Ching Wai, Ding Mian Zhi, Vempati Srinivasa

Rao, Min Woo Daniel Rhee, “Process Characterization of

Highly Conductive Silver Paste Die Attach Materials for

Thin Die on QFN”, Electronic Packaging and Technology

Conference, pp.372-378, 2012.

[12] Raymund Y. Agustin, The Effect of Glue Bond Line

Thickness (BLT) and Fillet Height on Interface

Delamination, ASEMEP National Technical Symposium,

pp.1-6, 2015.

[13] Ho Siow Ling, Leong Ching Wai, Germaine Hoe Yen Yi,

Min Woo Daniel Rhee, “Impact of Advanced Materials

on Power Cycling Performance and Process Dependent

Stresses of QFN”, Electronic Packaging and Technology

Conference, pp.119-124, 2012.

10

Lin Bu received the Ph.D. degree in

power engineering and engineering

thermophysics from Xi’an Jiao Tong

University, Xi’an, China, in 2010. She

was a Research Fellow with Nanyang

Technological University, Singapore,

from 2010 to 2012. Since 2012, she has

been a Scientist with the Institute of

Microelectronics, Agency for Science,

Technology and Research, Singapore. She has authored or co-

authored more than 20 technical papers in refereed journals

and conference proceedings. She is experienced in multi-phase

fluid flow and thermal dynamics in the semiconductor, energy,

and academic environments.

Wai Leong Ching received the Bachelor

Degree of Materials Engineering from

Nanyang Technology University of

Singapore. She worked in semiconductor

packaging Industrial for two years after

graduated from University. Since then,

she has been with Institute of

Microelectronics, Singapore, where she

is currently the Senior Research

Engineer of Technology Development-

Advanced Packaging.

Ho Siow Ling is currently a scientist in

the Institute of Microelectronics (IME),

Agency for Science, Technology and

Research (A*Star), Singapore. She

completed her PhD in Mechanical

Engineering at the National University

of Singapore (NUS) and is now

responsible for projects that are related to advanced

packaging, electronics for aerospace applications and

packaging solutions for power electronics. Her research

interests include delamination, modeling of material failure

processes and simulation of mechanical phenomena observed

in electronics packaging.

Min Woo Rhee was born in Seoul, South Korea, in1973. He received the B.Eng (Hons) and the PhD degree in chemical

engineering from the Sogang University, South Korea. He has

more than 15 year experience in microelectronics packaging

research and development for both industry and research

institute and also has extensive experiences in new packaging

& material development, modeling and characterization. In

IME-A*STAR, he is currently leading power module and

ruggedized electronics group and industry consortium projects

for automotive, oil & gas, deep sea exploration and aerospace

industries. He also has project leading experiences of lots of

public funded and industry projects related with material and

new packaging development such and MEMs and 3DIC

packaging since his join IME in 2011. Before he joined IME,

he had developed automotive three phase inverter module for

power electronics in Fairchild semiconductor R&D group as a

principle engineer which were successfully applied for mass

production for automotive industries. He also had worked for

Amkor technology R&D from 1999 to 2010. During his

working period in Amkor, he was the senior manager and

leader of material characterization modeling and failure

analysis group and resolved lots of chronicle failure and

quality issues with worldwide semiconductor companies. He

received ‘The best employee of the year award in 2009’. He

has authored and co-authored more than 60 journal and

conference papers and about 20 patents in microelectronics

materials and packaging fields.