einführung in die surface mount technology (smt ... · projekt zur finiten elementmethode. tu...

Technische Universität BerlinFakultät für Verkehrs- und Maschinensysteme , Institut für Mechanik

Lehrstuhl für Kontinuumsmechanik und Materialtheorie, Prof. W.H. Müller

Copyright © Prof. Dr. rer. nat. W.H. Müller, e-mail: [email protected], 20111Projekt zur finiten Elementmethode. TU Berlin, 0530 L 164, SS 2011

Einführung in die Surface Mount Technology (SMT):

Komponenten und Materialien, Zuverlässigkeit, FE-Modelle

Prof. Dr. Wolfgang H. MüllerFakultät V

Institut für MechanikLehrstuhl für Kontinuumsmechanik und Materialtheorie

Technische Universität Berlin 10587 Berlin




Institute of MechanicsChair for Continuums Mechanics and Materials Theory

Our Expertise: “Computer Modeling of Complex Materials and Processes“




Specimen

Die

GuidePunch

10 10 10 10 100 -2 -4 -6 -8 m

FE-Berechnungen(z.B. LebensdaueranalyseMikroelektronikverbunden)

Simulation des Lasersschutzgasschweißens

Grenzflächenbruchmechanik(z.B. Schweißnähtenin Verbrennungskammern)

SimulationmikrostrukturellerEntwicklungen (z.B. Lote, NiAl,Keramiken)

MessungmechanischerWerkstoffparameter(z.B. Lote)

In-situ Tiefseebohrproben-nahme und -analyse




Die zerstörerische Wirkungvon Thermospannungen

Im Großen:




Im Kleinen:

Lebensdauerprognose ?




OutlineSurface Mount Technology (SMT):

typical componentsmaterials usedproduction stepsquality and reliability control

FE-Simulation of SMT-Components:recent example - the Hitap FCOB and substructuresgoalsmeshing / submodeling techniqueintroduction to strength of materials conceptscontents of an ABAQUS input filelifetime prediction




Typical SMT Components IThe trend towards extreme miniaturisation

chip carriersLCDs anddisplays

resistors andcapacitors




Typical SMT Components IIMiniMELF ceramic resistor:

aging of SnPb solderfalse alignment of parts on the PC-Boardthermal mismatch of materials




Typical SMT Components III

Ball Grid Arrays (BGAs):micro-structural coarsening of solder during thermal ageinginterface cracks




Typical SMT Components IV

Chip Scale Packages (CSPs):

in a pacemaker: in a mobile phonewith video unit:




Typical SMT Components V

Chip Scale Packages (CSPs):“flexible interposer CSPs”

(a) compression bonding (face down), (b) wire bonding (face up)

“rigid substrate CSPs” (= setup as a “mini BGA”)

elastomerchip

substratesolder ball

gold-plated bumps




Flip-Chips (FCs):

used in Nasa’s “fetal monitor unit”

Si-chip, activeside “face down”

solder bumps(first level interconnect)

Typical SMT Components VI

solder balls(second level interconnect)

underfill




lead containing and lead free solders, binary, ternary or quartenary

alloys, eutectic or near- eutectic, made of Sn, Pb, Cu, Ag, In, Sb, Bi , ...

Typical Materials Used in SMT I

stress-strain diagram: strength diagram:




SMT solder joints: formation of interface cracksmicrostructural coarsening

ball grid arrays and solder ball before and after 4000 temperature cyclesaging at RT after (a) 2h, (b) 17d and (c) 63d

(a) after solidification, (b) 3h and (c) 300 h at 125°CMELF miniature resistor and solder joints before and after 3000 temperature cycles

Typical Materials Used in SMT II




Experimental determination of local material properties VIMaterials & Structures investigated (I)

Formation of intermetallic compounds in microelectronic solder connections

IMC formation and ripening of“scallops” at the interface

Scallop morphology of Cu-Sn intermetallics(a) SnPb/Cu at 200 °C, 10 min(b) SnBi/Cu at 160 °C, 5 min(c) SnAg/Cu at 240 °C, 5 min(d) Sn/Cu at 250 °C, 5 min, Kim & Tu [1996]




Materials & Structures investigated (II)

Formation of intermetallic compounds in microelectronic solder connections

IMC formation and ripening at the interface and in the solder bulk(K. Müller, NM Bayreuth)

SnAgCu +In

1x Reflow 2x Reflow

Ag3Sn Cu6Sn5

Experimental determination of local material properties VII




Materials & Structures investigated (III)

EDX analysis of the chemical species and composition(K. Müller, NM Bayreuth andJ. Villain, FH Augsburg) Sn La1 Ag La1

Cu La1 In La1

Nd La1 O Ka1

Experimental determination of local material properties VIII




Experimental determination of local material properties IXMaterials & Structures investigated (IV)

EDX analysis of the chemical species and composition(K. Müller, NM Bayreuth andJ. Villain, FH Augsburg)

Cu1Ag70In7,7Sn21

Cu3Ag61In8Sn27,8

Ag69In5,7Sn25

Ag3Sn

Ag3Sn




“bumping” of silicon chips (after IZM)

Typical Materials Used in SMT III




Typical Materials Used in SMT IV

squeegee

copper pad

smooth solder bumps after reflow-heating

syringes with solder paste

solder bumps after stencil-printing

stencil

solder paste

“putting-on” solder pasteby stencil-printing: or by “injection”:




restricting solder flow: solder stop masks

copper pads for solder ball connect

Typical Materials Used in SMT V




PC-Boards: “Cu-circuits surrounded by epoxy”,e.g. FR-4 =“flame-retardant 4 material substrate”

Typical Materials Used in SMT VI

Si-chip

solder ballHDS cracks

“copper vias”“micro via”




underfill: “corset” used to mechanically stabilisetiny solder bumps in CSPs

Typical Materials Used in SMT VII




chipunderfill

Printed Circuit Board

50 μm

siliconchipunderfill

SolderBall

delamination crack

20 μm

problems with underfilling

Typical Materials Used in SMT VIII




process chain: placement machines:

reflow oven:

SMT Production Steps




destructive analysis of SMT parts by means of optical microscopyQuality and Reliability Control I

~ 30-40 mm

resin




solder ballsQuality and Reliability Control II

Heriot-Watt University

Test-board analysis (Solder)

Analysis By

Siemens, Germany

Features

CSP 3 (Row 4 Balls)

Ball, 200x magnificationCSP 5

Balls, 25x

- Voids in

solder

CSP 4 (Row 2 Balls)

Ball, 200x

- Void in

solder.

- Separa-

tion from

top inter-

face layer.

CSP 4 (Row 4 Balls)

Ball, 200x

- Voids in

solder.



Analysis By

Siemens, Germany

Features

CSP 3 (Row2 Balls)

Ball, 200x

- Voids in

solder.

CSP 4 (Row 2 Balls)

Balls, 100xFCOB 3

100x

- Voids in

solder.

CSP 3 (Row 5 Balls)

Ball, 400x

- Interface

cracking in

solder balls.




Quality and Reliability Control III



Analysis By

Siemens, Germany

Features

CSP 6 (Row 2 Balls)

Ball, 200xCSP 5

Ball, 200x

- Cracks At

top of solder

balls close to

interface

layer. Total

separation.

CSP 6 (Row 2 Bumps)

Bump, 200x

FCOB 2

Bump, 200x

- Delamina-

tion of inter-

face copper

pads.

- Solder dete-

rioration.

CSP (Row 5 Balls With Bumps)

Bump, 200x

- Severe

damage to

solder bumps

solder balls and bumpsHeriot-Watt University


Analysis By

Siemens, Germany

Features

CSP 3 (Row 4 Balls With Bumps)

Bump, 400xFCOB 2

200x

- Poor solder

deposition






Features

CSP 3 (Row 1 Balls)

μ-via 100x

CSP 3 (Row 2 Balls)

μ-via, 100x

CSP 4 (Row 4 Balls)

μ-via, 200xVia Region (4th Sample Row)

Via, 200x

CSP 6 (Via Region – 1st Sample Row)

Top of via, 100xCSP 6 (Via Region – 1st Sample Row)

Bottom of via, 100x

Quality and Reliability Control IVvias and microvias



Analysis By

Siemens, Germany

Features

Via Region (3rd Sample Row)

Via, 50x

(Slight Deformation)

narrowing

via




microvias

FCOB withmicrovias

Recent Example: the Hitap FCOB and substructures

FCOB = Flip-Chip-On-Board




FE-FCOB - Goals

development of a microelectronic control unit for “automotive applications” , i.e., operating temperatures T = 150°C and –45°C

design and reliability of the corresponding high temperature PCBoard?

lifetime of electrical connections therein (vias and microvias)?

development of thermal stresses/strains during temperature change within the vias and microvias?

accumulation of irreversible strains within the vias and microvias?




FE-FCOB - Goalsloading and fatiguing the structure by means of thermal cyclingas follows:

183

150

-40

1 2 3 4 5 6 7 8

Temp (°C)

Steps




Meshing and Submodeling Technique Iglobal model - w/o heatsink

chipbase line: 6 x6 mmthickness: 0.53 mm

underfillthickness: 0.13 mm

solder stop maskthickness: 0.03 mm

ISOLA-boardthickness: 1.5 mm

chipunderfill

solder stop mask

ISOLA-board




Meshing and Submodeling Technique IIglobal model - with heatsink

chipbase line: 6 x6 mmthickness: 0.53 mm

underfillthickness: 0.13 mm

solder stop maskthickness: 0.03 mm

ISOLA-boardthickness: 0.8 mm

gluethickness: 0.13 mm

heatsinkthickness: 1.5 mm

chipunderfill

solder stop mask

ISOLA-board

glue

heatsink




Meshing and Submodeling Technique III

D1

D2

ISO

DW

L1: 0.25 mmD1: 0.1 mmD2: 0.075 mmDW: 0.015/0.027 mmISO: 0.06 mm

electrolyticallydeposited copper

board, Isola

solder stop mask, underfill

submodel of a microvia




submodel of a via

submodel base length: 1.0 mm

via wall thickness: 0.022 mm

via inner diameter: 0.256 mm

via inner diameter: 0.65 mm

via length (with heatsink): 0.8 mm

via length (w/o heatsink): 1.5 mm

Meshing and Submodeling Technique IV




positioning the submodels (μ-vias)

Meshing and Submodeling Technique V

x

y3

1

4

2 5 6

x,y positions in mm

1: 2.2 , 2.5 2: 0.0 , 2.353: 0.0 , 0.34: 2.91, 4.05: 0.0 , 4.06: 0.0 , 5.8

base length FE-modelchip: 3 mmboard: 6 mm




positioning the submodels (vias)

Meshing and Submodeling Technique VI

x

y

4

5 6

x,y positions in mm

4: 2.91, 4.05: 0.0 , 4.06: 0.0 , 4.8




Meshing and Submodeling Technique VIIthe reason for the positions of the submodels: the global deformation of the board

(magnification factor 40)

(magnification factor 5)

(step 5, -40°C)




Introduction to Strength of Materials Concepts Istress in generalstress = force per unit area dim[stress]=N/mm2

stress in 1D

FAAF

=σnormal stress:

FA

shear stress:AF

=τ

⇒




Introduction to Strength of Materials Concepts IIstress in 2D

VF

stress tensor

xxσ

xxσ

yyσ

yyσ

yxσ

yxσ

xyσ

xyσ ⎟⎟⎠

⎞⎜⎜⎝

⎛σσσσ

=σyyyx

xyxxij

1st index represents component of the unitnormal of the surface the force is applied to

2nd index represents componentof the force acting on a surface

x

y




stress tensor - worked example I

Introduction to Strength of Materials Concepts III

x

yyyσ

yxσ

( ) 1,01,0 ==⇒= yx nnn

unit normaln

tThe force vector or “traction” can then be obtained from:

( ) yxyxxxyxyxxxxyx nntttt σ=σ⋅+σ⋅=σ+σ=⇒= 10,

yyyyxyyyyxyxy nnt σ=σ⋅+σ⋅=σ+σ= 10




total force on a flank - worked example II

Introduction to Strength of Materials Concepts IV

xxσ

xyσ normal of the flank

( ) 0,10,1 ==⇒= yx nnn

xxyxxxxt σ=σ⋅+σ⋅=⇒ 01

xyyyxyyt σ=σ⋅+σ⋅= 01

short-hand notation:

jijj

jiji nnt σ=σ=∑=

2

1

automatic summation w.r.t. 1,2 for all indices that appear twice

x

y




Introduction to Strength of Materials Concepts Vstress tensor in 3D

⎟⎟⎟

⎠

⎞

⎜⎜⎜

⎝

⎛

σσσσσσσσσ

=σ

zzzyzx

yzyyyx

xzxyxx

ij

symmetry: jiij σ=σ

,jiji nt σ=forces: { }{ }zyx

ji,,or

3,2,1,∈∈

this allows to assess the forces acting within a small piece of matterwithin a microelectronic component, e.g. the propensity for delamination

zzσ

x

z

y




Introduction to Strength of Materials Concepts VIstrain in general

strain = change in length divided by the original lengthdim[strain] = [-] (dimensionless)

strain in 1D

⇒

F

lΔl

llΔ

=ε




Introduction to Strength of Materials Concepts VIIstrain in 2D/3D

strain tensor - worked example

ix

⎟⎟⎠

⎞⎜⎜⎝

⎛

∂

∂+

∂∂

=εi

j

j

iij x

uxu

21

: position vector , iu : displacement vector

FlΔl

1x2x

3x( )

ll

xu

xu

xu

lxlxuu Δ

=∂∂

=⎟⎟⎠

⎞⎜⎜⎝

⎛∂∂

+∂∂

=ε⇒Δ==1

1

1

1

1

111

1111 2

1

( ) 0011 ==xu ( ) llxu Δ==11




Introduction to Strength of Materials Concepts VIIIHooke’s law in 1D

lΔl

A

ε=σ⇒Δ

=⇒=Δ EllE

AF

AEFll

σ

E : Young’s modulus , dim [ ]E 2mN

=




Introduction to Strength of Materials Concepts IXexperimental verification of Hooke’s law




Introduction to Strength of Materials Concepts XHooke’s law in 1D with thermal expansion

thel lll Δ+Δ=Δ

elastic thermal

part of elongationAEFll =Δ el

lTl th Δα=Δ

coefficient of thermal expansion

change in temperature

( )TETllE

AFTl

AEFll Δα−ε=σ⇒⎟

⎠⎞

⎜⎝⎛ Δα−Δ

=⇒Δα+=Δ




Introduction to Strength of Materials Concepts XIHooke’s law in 2D/3D with thermal expansion

( ) , TC klklijklij Δα−ε=σ

Recall that an automatic summation is implied whenever two of the same indices appear.

ijklC : stiffness tensor , : CTE’sklα

For isotropic materials ( - Poisson’s ratio = lateral contraction coefficient):

( ) ( ) ( ) ( ), 1221 1 jkiljlikklijijklEEC δδ+δδν+

+δδν−ν+

ν=

ν

klkl αδ=α

( ) ( ) ⎟⎠⎞

⎜⎝⎛ δΔα−ε

ν−ν

+δΔα−εν+

=σ⇒ ijkkijijij TTE 3211

⎩⎨⎧

≠=

=δlklk

kl if,0if,1




Introduction to Strength of Materials Concepts XIequilibrium of forces

0d0 =⇒=∑ ∫∫∂V

ii AtF

Using yields:,jiji nt σ=

0=∂

σ∂⇒

j

ji

x

Vx

AnV j

ji

Vjij dd0 ∫∫∫∫∫ ∂

σ∂=σ=

∂




Introduction to Strength of Materials Concepts XIIcombining equilibrium and Hooke’s law

⎟⎠⎞

⎜⎝⎛ δε

ν−ν

+εν+

=σ ijkkijijE

211

0=∂

σ∂

j

ji

x

⎟⎟⎠

⎞⎜⎜⎝

⎛

∂∂

+∂∂

=εi

j

j

iij x

uxu

21

⎪⎪⎪⎪

⎭

⎪⎪⎪⎪

⎬

⎫

( ) 021

112

22

=⎥⎥⎦

⎤

⎢⎢⎣

⎡

∂∂∂

+∂∂

∂

ν−ν+ jj

i

ji

j

xxu

xxuE

Lamé-Navier equations:

numerical solution required: ABAQUS




Introduction to Strength of Materials Concepts XIII1D incremental (time-independent) plasticity

yield condition: ( )plεσ=σ y

1D stress applied to material

yield stress (material specific)

loading rate unimportant




Introduction to Strength of Materials Concepts XIV

3D incremental (time-independent) plasticity I

stays as is, but: the 1D stress is replaced by a suitablecombination of all the components of the stress tensor, e.g. by the Huber-von Mises-Hencky equivalent stress:

,ijijSS23

eq =σ ijkkijijS δσσ31def.

−=

the yield condition:

( )plεσ=σ y




3D incremental (time-independent) plasticity II

Introduction to Strength of Materials Concepts XV

linear elasticity: incremental plasticity:

0=∂

σ∂

j

ji

x

klijklij C ε=σ

( )( )( )

( )ν+δδ+δδ

+ν−ν+

δνδ=

12

21 1

jkiljlik

klijijkl

E

EC

( ) ( )⎟⎠⎞

⎜⎝⎛ +++

−=

EE

SESCC

Ty

klijijklijkl

3121 12

3

2

el/pl

νσν

(tangent modulus)

numerical solution required: ABAQUS

0=∂∂

j

ji

xσ&

klijklij C εσ && el/pl=

plεσ && TE=




E.g., hardness (intuitive definition):Resistance of a material to surface penetration under mechanical load using an indentermade of a highly rigid material with a specifically shaped tip, e.g., a diamond pyramid (Vickers, HV, Berkovich HN, Knoop, HK) or a sphere (Brinell, HB)

Introduction to Strength of Materials Concepts XVIExperimental determination of local material properties I




Setup and Way of Operation of the Nanoindenter

Diamond (Berkovich Indentor)

x

z

y

Wheatstone Bridge:2 Condensors: C1, C22 Resistors: R1, R2

Pendulum Weight

Limit Stop for thePendulum

Pendulum

Motion of Pendulum

Joint

Specimen

Specimen Support

Condensor (C1)

CoilPermanent Magnet

NanoindenterNanoindenter LOT MicrosystemsLOT Microsystems

Introduction to Strength of Materials Concepts XVIIExperimental determination of local material properties II




(a) Vickers microhardness: the applied load and the dimensionsof the impression after the load has been removed.

(b) Berkovich nanoindentation: the diamond indentation depth as a function of the applied load during load-unload cycle.

Experimental determination of local material properties IIIWhat do we record?What do we record?




Vickers hardness is defined as the ratio of the load and the actual surface area of the permanent impression:

APHV =

PA

Nanoindentation hardness is defined by the ratio:

being the peak load and being the projected indentation area.

To compare we may write:

proj

max

APHN =

maxP projA

HNA

AHNHV <= proj

Experimental determination of local material properties IVHardness can easily be computedHardness can easily be computed




Young’s (reduced) modulus (Bulychev et al. 1973, Oliver & Pharr, 1990):

Yield strength (Fischer-Cripps, 2002):

i

i

rr EEEh

PSASE

22

proj

111,dd,

2ννπ −

+−

===

( )HNy ασ

+=

123

( ) ⇒=+= ijijyHN σσσατ23,12 max

α =70.3° effective cone angle

Experimental determination of local material properties VNanoindentation/ -hardness can be used to determineother mechanical properties




Experimental determination of local material properties XMaterials & Structures investigated (V)

Material properties of interface layer materials in solder connections ?

⇒ Cast intermetallics: Ag3Sn, Cu3Sn, Cu6Sn5, (Cu,Ni)3Sn, (Cu,Ni)6Sn5, and Ni3Sn4 (K. Müller, NM-Bayreuth)

Porosity !




Experimental determination of local material properties XIMaterials & Structures investigated (VI)

In situ-study of microelectronic connectionSnAgCu solder balls of a mounted CSPDie sides with Ni/Au finish, PCB-sides OSP-treatedformation of a Ni3Sn4 layer after first and substitute compounds such as (Cu,Ni)6Sn5after second reflow at die side

highly planar interface regiongood for nanoindents across interface




Pure intermetallic phases (I)

Test Setup:

depth controlled: max. depth= 1800 nmindents per grid:

7 x 7 indents = 49 indentshorizontal and vertical distance

between indents: 0.5 mm

0.5mm

0.5mm

Experimental determination of local material properties XII




Experimental determination of local material properties XIIIPure intermetallic phases (II): Hardness

0.0

1.0

2.0

3.0

4.0

5.0

6.0

Ag3Sn Cu3Sn Cu6Sn5 (CuNi)3Sn (CuNi)6Sn5 Ni3Sn4

hard

ness

[GPa

]

HN (rescaled)Vickers HV0.2




Pure intermetallic phases (III): More Hardness

1

2

3

4

5

6

7

0 200 400 600 800 1000load [g]

hard

ness

[GPa

]

Ag3Sn

Cu3Sn

Cu6Sn5

Ni3Sn4

including data by Ghosh (2003, Northwestern)

hardness depends on indentation load, overall material characteristic !

Experimental determination of local material properties XIV




Pure intermetallic phases (IV): Young’s modulus

0

20

40

60

80

100

120

140

160

180

Ag3Sn Cu3Sn Cu6Sn5 (Cu,Ni)3Sn (Cu,Ni)6Sn5 Ni3Sn4

You

ng´s

mod

ulus

[GPa

]

nanoindentationultrasound

Experimental determination of local material properties XV




Pure intermetallic phases (V): Poisson’s ratio

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

Ag3Sn Cu3Sn Cu6Sn5 (CuNi)3Sn (CuNi)6Sn5 Ni3Sn4

Pois

son'

s rat

ioExperimental determination of local material properties XVI




Test Setup:

depth controlled: max. depth= 1800 nmthree series of indentsindents per grid:

typically 8 x 9 or 9 x 9 indentssmall spacing to position indent inregion of intermetallic phases

SnAgCu Solder Ball: Die Interface (I)

NiIMC SnAgCu

Cu

Experimental determination of local material properties XVII




0.0

1.0

2.0

3.0

4.0

5.0

6.0

Cu Ni IMC SnAgCu

HN

[GPa

]

ball 1, array 1ball 2, array 1ball 2, array 2literature/own data

SnAgCu Solder Ball: Die Interface (II)

very small values !

Experimental determination of local material properties XVIII




SnAgCu Solder Ball: Die Interface (III)

0

50

100

150

200

250

Cu Ni IMC SnAgCu

You

ng´s

mod

ulus

[GPa

]

ball 1, array 1ball 2, array 1ball 2, array 2literature

small but not too small !

Experimental determination of local material properties XIX




56.24=κ

proj

max

APHN =

WOI

Determination of yield stress by direct and Work-Of-Indentation (WOI) approach

since:

( )HNy ασ

+=⇒

123

WOIlit. est.

proj

max

APHN =

SnAgCu

( ) maxmax

max

0

2

31d PhhhPWhcP

h

h

==⇒⋅= ∫=

( ) maxmax22

3max

proj

max ,9 h

hhh

WP

hAP

HN rc

c

≈=== ββκ

Experimental determination of local material properties XX




Contents of an ABAQUS Input File I

Four Important Ingredients to an ABAQUS Input File

node and element section

definition of symmetry andboundary conditions

material properties section

definition of loading conditions




Contents of an ABAQUS Input File II

node section

*NODE, NSET=ALL, SYSTEM=R 1,-3.6780360E-06,-5.1910880E-06, 6.4000000E-01 2,-3.0000000E+00,-3.0000000E+00, 6.4000000E-01 3,-3.6780360E-06,-2.7303920E-01, 6.4000000E-01 4,-3.6780360E-06,-5.3024260E-01, 6.4000000E-01 5,-3.6780360E-06,-7.6296500E-01, 6.4000000E-01 6,-3.6780360E-06,-9.7083440E-01, 6.4000000E-01 7,-3.6780360E-06,-1.1585370E+00, 6.4000000E-01 8,-3.6780360E-06,-1.3326420E+00, 6.4000000E-01 9,-2.8500000E+00,-3.0000000E+00, 6.4000000E-01 ...

node number (x,y,z)-coordinates of the nodes




element section

Contents of an ABAQUS Input File III

*ELEMENT, TYPE=C3D20R , ELSET=CHIP 261, 72, 69, 160, 162, 713, 707, 889, 892, 5617, 5618, 5543, 5619, 7259, 7260, 7261, 7262, 7263, 7264, 7265, 7266 262, 713, 707, 889, 892, 714, 708, 890, 893, 7259, 7260, 7261, 7262, 7267, 7268, 7269, 7270, 7271, 7272, 7273, 7274 263, 69, 70, 8, 160, 707, 709, 604, 889, 5620, 5621, 5536, 5618, 7275, 7276, 7277, 7260, 7264, 7278, 7279, 7265 ...

element number numbers of the nodes thatconstitute the element

name of the element setelement type: 20 nodes




Contents of an ABAQUS Input File IV

which symmetry and boundary are required?

fix corner nodein all directions make these nodes

move such thatsurface does not bend

these may moveonly up and down

nodes on side flanksmay not move perpendicularly




Contents of an ABAQUS Input File Vsymmetry and boundary conditions I

*TRANSFORM,NSET=XYSYM,TYPE=R 1, 1, 0, -1, 1, 0

transformation of side flank nodal coordinates

*EQUATION 2, 1654, 2, 1.0, 5461, 2, -1.0 2, 1657, 2, 1.0, 5461, 2, -1.0 ...

keeping front face of board straight




Contents of an ABAQUS Input File VI

symmetry and boundary conditions II

*BOUNDARY,OP=NEWBS000001, 1,, .00000E+00BS000002, 1, 2, .00000E+00 5164, 1, 3, .00000E+00 XYSYM, 2,, .00000E+00

name of node sets direction of constraintmagnitude

of constraint




material properties section I

Contents of an ABAQUS Input File VII

all materials were treated as linear-elastic (except the copper) with temperature dependent coefficients, e.g. the board:




material properties section II

Contents of an ABAQUS Input File VIII

*MATERIAL,NAME=BOARD*ELASTIC,TYPE=ENGINEERING CONSTANTS 1.4218E+4, 1.4218E+4, 7.109E+3, 1.500E-01, 4.000E-01, 4.000E-01, 6.182E+3, 2.539E+3, 2.539E+3, 223 1.3116E+4, 1.3116E+4, 6.558E+3, 1.500E-01, 4.000E-01, 4.000E-01, 5.703E+3, 2.342E+3, 2.342E+3, 298...

stiffness coefficients of the board (anisotropic),Ex, Ey, Ez, νxy , νxz, νyz at different temperatures

*EXPANSION,TYPE=ORTHO

1.7E-05, 1.7E-05, 5.1E-05

expansion coefficients of the board (anisotropic) αx , αx, αz




material properties section III

Contents of an ABAQUS Input File IX

strain [-]

stre

ss [M

Pa]

stress-strain curves for electrodeposited copper




material properties section IV

Contents of an ABAQUS Input File X*MATERIAL,NAME=COPPER*ELASTIC,TYPE=ISOTROPIC4.5086E+4, 0.34, 2084.3823E+4, 0.34, 2934.3994E+4, 0.34, 3933.9285E+4, 0.34, 4733.1028E+4, 0.34, 5732.1440E+4, 0.34, 673*EXPANSION,TYPE=ISO1.76E-5*PLASTIC156.0, 0.0, 208173.0, 0.02154, 208149.0, 0.0, 293163.4, 0.02160, 293146.5, 0.0, 393154.0, 0.02167, 393121.0, 0.0, 473127.0, 0.02192, 47387.5, 0.0, 57392.3, 0.02218, 57357.7, 0.0, 67363.5, 0.02231, 673

Young’s modulus,Poisson’s ratio overtemperature

CTE

yield stress vs.plastic strain overtemperature




typical plastic deformation of a via Lifetime Prediction I

183

150

-40

1 2 3 4 5 6 7 8

Temp (°C)

Steps

steady increaseor saturationof equivalent

plastic strain (PEEQ):

∫ εε=ε tijij d32 plplpl

eq &&




typical plastic deformation of a microvia

Lifetime Prediction II

183

150

-40

1 2 3 4 5 6 7 8

Temp (°C)

Steps

steady increaseor saturationof equivalent

plastic strain (PEEQ):

∫ εε=ε tijij d32 plplpl

eq &&




calculation of lifetime of plastically strained electrolyticallydeposited copper (Barker and Dasgupta, 1993):

Lifetime Prediction III

( ) ( ) 6.0155.0pl

2398.0201883.02

−− +=εΔ

ff NN

the increment of plastic strain accumulatedin a TCT -40°C/150°C/-40°C determines

the number of cycles to failure fN

plεΔ

Seite 95 Dr.-Ing. Tilman EckertProf. Dr. W.H. Müller

Lebensdauermodellierung Temperaturwechsel

1. Simulation des Aufbaus (FEA: Materialparameter, Lastbedingungen, Geometrie)

2. Extraktion der Schadensparameter 3. Einsetzen in Lebensdauergesetz (c1, c2, c3, c4 materialabhängig)4. Prognose Nf,TW - Zahl der Temperaturwechsel bis zum Ausfall

Schadensparameter (FEA)

Beschleunigte Laborbedingungen

Feldbedingungen

log(Δεp)log(ΔW)

Eckert, T., Tetzner, K., Bochow-Ness, O., Müller, W.H., Reichl, H., “Sensitivity Analysis of Technological Fabrication Tolerances on the Lifetime of Flip-Chip Solder Joints,” Proc. IEEE EuroSimE, Delft, 2009

L

h




Quelle:Darveaux et al., in BGA, Lau (ed.), 1995

Life time of solder balls after Darveaux:Combination of FE simulation and experiment

( ) 626,050 1036,1 −

⋅= crWN Δ

( ) 915,0101016,4dd −−⋅= crWNa Δ

crack initiation

crack growth

Lifetime Prediction IV

einführung in die surface mount technology (smt ... · projekt zur finiten elementmethode. tu...

Documents