Thermo-mechanical Behavior of WB-PBGA Packages with Pb-Sn Solder and Lead-free Solder Using Moire Interferometry

ᑚṪᄮ Ԫᩓתኢ ₚ῏⺂ ⁆἖ ᪺౺ὦ ᑚ἖ ᪺౺ ᰊ⃋

WB-PBGA ⱎ⧊⋦⁾ Ἒ-ݖת℧ ᗦ⼻ ֖೿

ₚᘯをÁݦዲݖÁ∢⋪ῶ^†

⛏ᚧద⹿ٶ ݖת؛⹿ᚦ

Thermo-mechanical Behavior of WB-PBGA Packages with Pb-Sn Solder and Lead-free Solder Using Moiré Interferometry

Bong-Hee Lee, Man-Ki Kim and Jin-Won Joo^†

Department of Mechanical Engineering, Chungbuk National University, 12 Gaesin-dong, Heungdeok-gu, Cheongju-si, Chungbuk 361-763, Korea

(2010 ੪ 8 Ὼ 10 ₢ ℷᬾ : 2010 ੪ 8 Ὼ 30 ₢ ⃒ֲ⽻℻ )

☮ ᆃ: ᔾ೪◚ ⱎ⧊⋦Ỷ ᧒῏ാ؆ ₮஺ ⁆἖ ᪺౺஺ ⽾ף ᘚ⽞ ⹪Ὰᩗ ๲ᑞỶ ᑚ἖ ᪺౺ᆂ ឆኚֲ ద◚ാ؆ ₮ఊ . ₚ ὦ Կ⁦ ᑚ἖ ᪺౺Ỷ ద⺂ ἖ڒ஺ ∢ᆂ ⃒ᇲ⁾ ᕂגآ ؛℻ ℧⁷ᩗ⁾ ئℶỶᩂ ₚሎỚⅲ ᣶ , ݖת℧₞ ᩗ⋮ₚা ᰆᇖ

ᩗ⁾ ئℶỶᩂ⁾ ἖ڒ஺ ዴₚ ₚሎỚ⋦⋦ ṰṾఊ . ᘞ ઢᑞỶᩂ஺ ᑚṪᄮ Ԫᩓתኢ ₚ῏⹾ἒ ⁆἖ ᪺౺ὦ ᑚ἖ ᪺౺ ᰊ⃋

WB-PBGA ⱎ⧊⋦ ז⺏◚⁾ ὎೪ᗦ⽺Ỷ ద⺂ Ἒ - ݖת℧ ֖೿ ⺚ᩃ⹾ἦఊ . ᰊᰂԪ ᑚṪᄮ Ԫᩓתኢ ₚ῏⹾ἒ ԧ ὎೪

ఎתỶᩂ ᗦ‪ ᚪⴒኢ া⧦৚஺ Ԫᩓᑚ௒ኢ ỡ؆ , ܞᆂᚦ⩖ ⁆἖آ ᑚ἖⁾ ᪺౺ ↖₞⯞ኢ Լ஺ WB-PBGA ⱎ⧊⋦⁾ ڣ ゾ ᗦ⼻ ֖೿ ᔵ ᪺౺ ᘢ⁾ ᗦ⼻ኆ ᝪٶ ᚪᩃ⹾ἦఊ . ᚪᩃזآኢ ᘚ᎚ ⁆἖ ᪺౺ ᰊ⃋ ⱎ⧊⋦ ז⺏◚⁾ ᪺౺ ᘢ⁦ ➏ ףת ᚦܢ₞ #3 ᪺౺ ᘢỶᩂ ᕂᨃ⹾஺ Kఎᗦ⼻ኆₚ ⰲ᪶Ỷ ⦖ ἧ⻋ ᔞ❾᎖ , ᑚ἖ ᪺౺Ԧ ᰊ⃋ൂ ⱎ⧊⋦ ז⺏◚⁾ ᪺

౺ ᘢ⁦ Ԧ⃋ ᔺދ ᚦܢ₞ #7 ᪺౺ ᘢỶᩂ ᕂᨃ⹾஺ ᬾ⋧ᗦ⼻ኆₚ ⰲ᪶Ỷ ⦖ ἧ⻋ ᔞ➆ ֩⁢ᆂ Ἦ❇ൂఊ . ༶⺂ ᑚ἖ ᪺

౺ ᰊ⃋ ⱎ⧊⋦ ז⺏◚஺ Կ⁦ ὎೪ ↖֚Ỷᩂ ⁆἖ ᪺౺ ᰊ⃋ൂ ⱎ⧊⋦Ỷ ᝪ⺚ ڣゾ ᗦ⼻ₚ 『Ṓ ⦒ֲ ᕂᨃെ ᣶ Ṫ௮Ⴂ

᪺౺ ᘢ⁾ ⁆⿎ᗦ⼻ኆ೪ 10% ℻೪ ⦒ֲ ᕂᨃ⹾஺ ֩⁢ᆂ া⧦াᩂ Ἒᗦ⼻Ỷ ⁾⺂ ⰲ᪶Ỷ ✎ả⺆ ֩⁢ᆂ Ἦ❇ൂఊ .

Abstract: Pb-Sn solder is rapidly being replaced by lead-free solder for board-level interconnection in microelectronic package assemblies due to the environmental protection requirement. There is a general lack of mechanical reliability information available on the lead-free solder. In this study, thermo-mechanical behaviors of wire-bond plastic ball grid array (WB-PBGA) package assemblies are characterized by high-sensitivity moiré interferometry. Experiments are conducted for two types of WB-PBGA packages that have Pb-Sn solder and lead-free solder as joint interconnections.

Using real-time moiré setup, fringe patterns are recorded and analyzed for several temperatures. Bending deformations of the assemblies and average strains of the solder balls are investigated and compared for the two type of WB-PBGA package assemblies. Results show that shear strain in #3 solder ball located near the chip shadow boundary is dominant for the failure of the package with Pb-Sn solder, while normal strain in #7 most outer solder ball is dominant for that with lead-free solder. It is also shown that the package with lead-free solder has much larger bending deformation and 10% larger maximum effective strain than the package with Pb-Sn solder at same temperature level.

Keywords: Lead-free solder, WB-PBGA package, Thermal deformation analysis, Moiré Interferometry, Thermo- mechanical behavior

1. ᩂ ᆆ

ԧ↫ K₶⅂ⶮ⁾ ℷ⺏⅂ᆂ Ḗἒ ὺ౾ ⁆἖ ᪺౺஺ ఊ ኞ ⺏ܮỶ ᝪ⺚ Ԧ׏ₚ ᰞ؆, Kݖ℧, ݖת℧, Ἒ℧⁢ᆂ ῖᬾ⺂ ᩗ⋮ Ԧ⋦؆ ₮ఊ஺ ⃋ℶ ๲ᑞỶ K₶᧖ừỶᩂ 50੪ ₚ᧧ ⁆῏⹾ֲ ᧒῏ാỚ ὺఊ. ܞᄒা K ᩞת℧₞

⽾ףᘚ⽞ ℻╫⁢ᆂ ৏ ₚ῏⺂ K₶ ⅂ⶮ⁾ ᨃ᧖⁦ ⚂

ܢ Իᅋ⺂ ܂⅂ኢ ᕁ؆ ₮ఊ. 2006੪ 7Ὼᚦ⩖஺ EU⁾

WEEEὦ RoHSኢ ∷ᰒ⁢ᆂ ⁆ᄣỶᩂ஺ ৏ₚ ⴒ⺎ൂ K

₶⅂ⶮ ᨃ᧖⹾֖া ᬾ₫⺆ ᬾ Ử೪ᆃ ܂⅂⹾ἦ؆, ᔞ ړ ท ఊኞ ᩆ⋪ړỶᩂ೪ ৏⁾ ᧒῏ ܂⅂⹾஺ ڒ◚℧

₞ ת⾳ ⋪⺯ᰂ⧊؆ ₮ఊ. ₚᆂ ₞⺚ ⁆἖ ᪺౺ኢ ద◚

⹾ݖ ‪⺂ ᑚ἖ ᪺౺⁾ ἖ڒԦ ⾂ᕂギ ⋪⺯ാ؆ ₮ఊ. ᑚ

἖ ᪺౺஺ ݖ↚⁾ Ω῏⁛ℶ ᪺౺(eutectic solder, 63Sn/

†

Corresponding author

E-mail: [email protected]

37Pb)

(high melting solder, 90Sn/10Pb)

∢⃒ᇲ₞∢ᩃ

(Sn)

(Ag),

ዒ

(Cu),

(In),

(Bi)

ᇲኢዲข஺ᕏ⻋⁢ᆂՂᕂാ؆₮ఊ

.

῏ാ஺᪺౺⁾ᩗᚪ⁢ᆂ஺∢ᩃ

,

,

(Sn-Ag-

Cu, SAC)

,

Ỷద⺂἖ڒ஺∢ᆂ⃒ᇲ⁾ᕂגآ؛℻℧⁷ᩗ⁾ئℶ ỶᩂₚሎỚⅲ᣶

,

Ỷᩂ⁾἖ڒ^1-3)஺ዴₚₚሎỚ⋦⋦ṰṾఊ

.

᪺౺ኢ᧒῏⹾஺K₶ⱎ⧊⋦ท⁾ז⺏◚ชỶ὎೪ᗦ

⽺Ԧᨃݖ᎚ڒᩗ⹾஺⃒ᇲ⁾ἚⱣ╣תᬾ╎ₚὦ᪺౺⁾

὎೪⋦ᕖ℧₞ᝪᩆ⼻ᩗ⋮ᆂ₞⺚⅂↖؛℻∷Ỷ༶஺

᧒῏∷Ỷ܆₢⹾⋦Ṱ⁦ᗦ⼻آ⁷ᅋ⋷∷ₚᕂᨃ⹾؆

,

זړⰲ᪶ₚাᚮჯท⁾ᑞ⅂Ԧᕂᨃ⺂ఊ

.

⋦⁾ףῖ஺⅂ⶮ᧒῏∷Ỷ∢ݖ℧₞Ἒ⹾∷⁢ᆂ₞⺚

℧❛ᚪዒ༶஺⹢ᆂⰲ᪶ᚮჯₚ₶∢ᕂᨃ⹾஺ಖ

,

⁾ⱎ⧊⋦⚺ᩞԦ౺ῗ؆⋷℧⽺

,

೪Ԧ౺ᰒ⺚⋮֩⁢ᆂἮ᧧⹾؆₮ఊ

.

⋦⹾؆᪺౺₶◚⁾⹢ᆂᬾᎫ⳯Ԧ⹾ݖ‪⹾ἒԦ᪳ᬾ

Ꭻᰂ⻾

(accelerated thermal cycling, ATC test)

ᰆᇖᩗ⳯Ԧኢ⹾؆

,

.

⋦ዲₚᰂ⻾⁢ᆂᚦ⩖ז℻ാ஺⹢ᆂᬾᎫ⿅ᬾ஺ⱎ⧊⋦

ᩊת⁾ᝪٶኢ‪⺚ᩂ஺⁆῏⹾ֲ᧒῏െᬾ₮⁢া

,

᪶Ỷₚኚ஺ԧⱎ⧊⋦⃒ᇲ⁾Ἒ℧

-

Ỷ஺⅂⺂ൂ℻ᘚዲ⅂؛⺂ఊ

.

⚂ܢỶᄮₚΩኢ᧒῏⹾஺ᑚṪᄮԪᩓתݖᭆₚՂᕂ

ാỚṪ∢સ⁦℻ᔦ೪ኢԦ⋦؆⁷῏ാ؆₮ఊ

.

Ԫᩓᖻ⁦℻ᔦ೪Ԧᰊ⻾ᕏᖻ∷ᝪٶ℧સ؆ᝪℷ☯⁢ᆂ K◚ἧἓ⁾ᗦ⼻᧧⨂ኢ❇℻⺆ᬾ₮⁢᎖∢‪⽾ףỶᔢ Զ⹾⋦Ṱఊ஺⃋ℶԦ⋦؆₮ఊ

.

ᄮԪᩓᖻ⁦⚂ܢỶ☮᪲⼻K₶ᚦⶮช⁾Ἒᗦ⼻⺚ᩃ^4-9) ทỶ⿎آ℧⁢ᆂₚ῏ാỚὺఊ

.

I/O

ᔾ೪◚ⱎ⧊⋦ᆂਸ਼ዒḖₚ؆₮஺

WB-PBGA

ద᧧⁢ᆂ⹾ἒ⁆἖᪺౺ᰊ⃋ⱎ⧊⋦ὦᑚ἖᪺౺ᰊ⃋

ⱎ⧊⋦⁾὎೪ᗦ⽺Ỷ๖ኚ஺Ἒᗦ⼻ᰊ⻾آܞ⺚ᩃᬾ

⺯⹾ἦఊ

.

೪஺⦖╎ₚԦ₮⁢᎖ܞỶ๖Ⴂ᧒῏⹾஺Ꮦ๏ᘛ⺏⅂

ὦⱎ⧊⋦ݖⰶทڒᩗ⃒ᇲ⁾ݖת℧ᑢᩗ❾೪ఒႢ⋮

ᬾ₮ఊ

.

ᅊ⹾ἒᗦ⼻֖೿ᰊ⻾℧⁢ᆂ⺚ᩃ⹾؆ᝪٶ⹾ἦఊ

.

ᰂԪᑚṪᄮԪᩓתኢₚ῏⹾ἒԧ὎೪ఎתỶᩂᗦ‪ᚪ ⴒኢা⧦৚஺Ԫᩓᑚ௒ኢỡ؆

,

⁾᪺౺↖₞⯞ኢԼ஺

WB-PBGA

᪺౺ᘢ⁾ᗦ⼻ኆᝪٶᚪᩃ⹾ἦఊ

. 2. ᑚṪᄮ Ԫᩓת ᰊ⻾

2.1. ᑚṪᄮ ԪᩓתỶ ⁾⺂ ᗦ‪ ❇℻

ᑚṪᄮԪᩓᖻ

(moiré interferometry method)

⁾℻⺚⋪

2

(x,y)

া⧦৚஺ط⹿℧₞ᰊ⻾ᕏᖻ¹⁰⁾ₚఊ

.

⁾ⶂ᎚Ỷᩂԧԧ

x

U

y

V

ద⺂ทᗦ‪؇ᩆা⧦৞ఊ

.

஺ఊ⁲آԿ⁦ᰃ⁢ᆂת᧖െᬾ₮ఊ

.

(1)

ἒݖᩂNx(x,y)ὦNy(x,y)஺‪❾Ỷ๖Ⴂᚪⴒ⹾஺℻⺚

⋪ℶỶద⺂Ԫᩓᑚ௒⁾╎ᬾₚఊ

.

⾲℮׏₶⁾؛Ԫ∢ⰲᬾfs

=1200 lines/mm

Ԫᩓᑚ௒᧒ₚ஺

0.417

m

.

Ԫᩓᑚ௒ᆂᚦ⩖ỡỚ⋪ᗦ‪ᚪⴒᆂᚦ⩖⳯᎚৚⁾ᗦ⼻

ኆڒ⺆๲Ỷ஺ఊ⁲⁾ᰃₚ῏⹾ἒת᧖⺆ᬾ₮ఊ

.

(2)

2.2. ᰂⳞ ᔵ ᰊ⻾ᕏᖻ

ᘞઢᑞỶᩂ஺⁆἖᪺౺ὦᑚ἖᪺౺ᆂᰊ⃋ൂ

WB- PBGA(wire-bonding plastic ball grid array)

2

ద⹾ἒᰊ⻾ᬾ⺯⹾ἦఊ

.

Ἒᗦ⼻ᩂᆂᝪٶ⺆ᬾ₮೪ᆃᰊ⻾῏౺ᔞⱎ⧊⋦ኢ

⅂؛⹾؆ ₮஺

Topline

BGA225T1.5-

DC15(

)

BGA225T1.5C-DC15(

)

.

⁆἖᪺౺஺

Sn 63%(wt), Pb 37%(wt)

₮஺Ω῏⁛ℶ⁾᪺౺

(eutectic solder, Sn37Pb)

,

᪺౺஺

Sn 96.5%(wt), Ag 3.0%(wt), Cu 0.5%(wt)

ᝪኢԦ⋦؆₮஺

Sn-Ag-Cu

(SAC305)

.

K◚℧₞

WB-PBGA

Fig. 1

,

Ꮦ๏⽺⺏ᑢᔵ

BT

,

⁾⦒ݖ஺

6

6 mm

24

24 mm,

U x y( , ) 1 2fs

---Nx(x y, )

= U x y( , ) 1

2fs

---Ny(x y, )

=

εx ∂U ---∂x 1

2fs

--- ∆N---∆x^x

≅

= εy ∂U

---∂y 1 2fs

--- ∆N---∆y^y

≅

= γxy ∂V

--- ∂U∂x ---∂y 1

2fs

--- ∆Ny

--- ∆N∆x +---∆y^x

≅ +

=

Fig. 1. Schematic of the WB-PBGA Package.

߾஺

3.5 mm

.

15

15

἖᪺౺ᘢ⽟⁦ᑚ἖᪺౺ᘢₚᔺ൷ⰶᏎặ⁢ᆂܞዒข ኢₚሎ᎖ℷ╏ാỚ₮⁢᎖

,

2

᧒Ỷᩂ⅂؛⹾؆ ₮஺൶߾

1.4 mm

PCB(Model P/N

967002)

.

1.5 mm,

ₚ஺

0.55 mm

0.95 mm

.

⳯᎚৚⁾

2

᎚ₚԦ⃋⦒ֲা⧦া೪ᆃఊₚṪᏒข⫗ₚ῏⹾ἒⱎ

⧊⋦ኢ℮ఎ⹾؆

,

ỡỮఊ

.

‪⹾ἒⱎ⧊⋦ኢὊ᜶Ỷ੉؆

80

C

2

Ṯ⁆⋦ᰂ⡖ఊ

.

ᝪൂ⾲℮׏₶ᏖขὦᰂⳞℷ╏⹾ἒ

24

⿪ᚪዒ⹾ἒ⾲℮׏₶

(1200 line/mm)

Ớ৚Ữఊ

.

὎೪ᗦ⽺Ỷ๖ኞᔞ᪲ᗦ⼻❇℻⹾ݖ‪⺂ᰊ⻾⃋❾

஺

Fig. 2

❾ᆂڒᩗാỚ₮ఊ

.

Joo

₢⹾ֲ⋪⺯⹾ἦఊ

. He-Ne

זൂطᩒ⁆⁾ঃỶᩂڒ᎚⁾ⰲ᎚Ԧ⋦؆Ⲣ⋪ខ⁦

6"

(parabolic mirror)

(collimated beam)

.

⁦⯟ᗪギ⅂₷ൂᏎṪᄮԪᩓת⁾Ṯ⏣

4

াପỚᔾ᧒ാ؆

,

4

ാỚ⾲℮׏₶Ԧᚦ╏ൂᰂⳞ⁾ⶂ᎚Ỷ᧧⹾↲ῖ

4

Ỷᩂ₫᧒ԧ

49.4

.

℮ാỚ Ԫᩓ ₢⁢⧎ Ԫᩓᑚ௒ ἧ᧧⁦ ⋷طᄲ⊮

(collecting lens)

CCD

ൂఊ

.

ῶ⹾஺὎೪ᆂᰂⳞ⁆⋦ᰂ⧊ݖ‪⹾ἒᰊᰂԪ⅂Ớ ԦԦோ⺂὎೪╺ᖪኢط⹿⃋❾ὦ἖ז⹾ἒ᧒῏⹾ἦఊ

.

ᰂⳞ὎೪╺ᖪṮỶᩂ؆℻⺂⿪֖῞ช℻ᅒ⹾؆Ԫ ᩓתK◚ỶԻ◚⾲K∢ỚᰂⳞآԪᩓת⁾ᕏ⻋₢

❾ᰂ⡖ఊ

.

ᗦ‪⃋

(null field)

Ữఊ

. Fig. 3

(20

C)

50

C

75

C

100

C

125

C

,

ₚᗦ⼻Ỷἧ⻋∢஺⋦ኢṲṪᘚݖ‪⹾ἒ

125

C

60

.

6

C/min(10 s/

C)

ᆂ⹾ἦ؆Ԫᩓᑚ௒ኢ❇℻⹾ἒݖᆃ⺆ᬾ₮೪ᆃԧ὎ ೪ఎתỶᩂ

2

.

Fig. 2. Moiré interferometry system with environmental chamber.

Fig. 3. Temperature excursion for the experiment of thermal deformation.

Fig. 4. Representative fringe patterns of the WB-PBGA Package assembly with Sn37Pb solder joints.

3. WB-PBGA ⱎ⧊⋦⁾ Ἒᗦ⼻ ֖೿

Fig. 4ὦ Fig. 5஺ ԧԧ ⁆἖ ᪺౺ὦ ᑚ἖ ᪺౺ኢ Լ஺

WB-PBGA ⱎ⧊⋦Ỷ ద⹾ἒ ԧ ὎೪ ఎתỶᩂ ݖᆃ⺂ U, V ᗦ‪ኢ া⧦৚஺ Ԫᩓᑚ௒ኢ ᘚἒ∢؆ ₮ఊ. ܞዢỶᩂ

஺ ₶ᩞ⺂ Ԫᩓᑚ௒ኢ ᘚₚݖ ‪⹾ἒ Ὂኞ⏣ ᔾ⏣ዲ ⽻ ద⹾ἒ া⧦৚Ữఊ. ⁆἖ ᪺౺ኢ ᰊ⃋⹾؆ ₮஺ WB- PBGA ⱎ⧊⋦⁾ U ᗦ‪ኢ া⧦৚஺ Ԫᩓᑚ௒ኢ ᘚ᎚ Ἒ Ᵽ╣תᬾԦ ৔⁦ ᔾ೪◚ ➏ₚ ₮஺ ᚦᚪỶᩂ஺ Ԫᩓᑚ௒

⁾ Ԫ׏ₚ ਹỚᩂ ₷⁦ ᗦ⼻ኆₚ ᕂᨃാỮ؆ ἚⱣ╣תᬾ

Ԧ ⦖ Ꮦ๏ ᔵ PCBᚦᚪỶᩂ஺ Ԫᩓᑚ௒⁾ Ԫ׏ₚ ↖ᔦ

⹾ἒ ⦖ ᗦ⼻ኆₚ ᕂᨃാỮ⁲ Ṳ ᬾ ₮ఊ. Ꮦ๏ ᚦᚪآ PCBᚦᚪ⁾ Ԫᩓᑚ௒ Ԫ׏ ᝪٶ⹾ἒ ᘚṾ ๲ Ꮦ๏ᚦ ᚪ⁾ Ԫᩓᑚ௒ Ԫ׏ₚ ảԪ ౺ ↖ᔦ⹾ֲ ݖᆃാỮ⁢᎖

PCB ᚦᚪآ Ꮦ๏ ᚦᚪỶᩂ஺ ᧧⹾ᕏ⻋⁢ᆂ ֖⁾ ⋧ᩆ℧

⁢ᆂ Ԫᩓᑚ௒Ԧ ⼻ᩗാỚᩂ ὎೪Ԧ ᧧ᯟ⺎Ỷ ๖Ⴂ ∢ᆂ

ᬾ⳯ᕏ⻋⁾ Ᵽ╣ₚ ₢Ớ৒؆ K◚℧⁢ᆂ ‪ᆂ ᘢᆃ⺂ ڣ ゾᗦ‪(∩)Ԧ ᔞ᪲⹾ֲ ₢Ớ৒⁲ Ṳ ᬾ ₮ఊ.

᪺౺ ᘢ ᚦᚪ⁾ Ԫᩓᑚ௒஺ ԧԧ⁾ ᪺౺ ᘢỶᩂ ᧧ట ギ ఊኞ Ꮞặ ᘚₚ᎖, ᬾ⳯ᕏ⻋⁾ Ᵽ╣, ⱎ⧊⋦ᚦᚪآ PCB ᚦᚪ⁾ ἚⱣ╣ ╎ₚᆂ ₞⺂ Kఎᗦ⼻ ᔵ Ի◚⾲K (rigid body rotation)ₚ ᘛ⺏℧⁢ᆂ ᕂᨃാỮ⁲ া⧦৞

ఊ. ὎೪Ԧ ᧧ᯟ⹾᎚ ᗦ⼻ₚ ⋃Ԧ⹾ἒ Ԫᩓᑚ௒Ԧ ↖ᔦ

⺚⋦᎖ ὎೪⁾ ᧧ᯟỶ ๖Ⴂ 125^oCݲ⋦஺ ᩆ⼻℧⁢ᆂ ᗦ

⼻ₚ ⋃Ԧ⹾஺ ⼻⨂ኢ ᘚ₞ఊ. 125^oCỶᩂ 60ᚪ ೿Ṯ ⁆

⋦ᰂ⧎ ⿪⁾ V ᗦ‪ኢ া⧦৚஺ Ԫᩓᑚ௒Ỷᩂ஺ ὎೪ ⁆

⋦ᰂԪ ೿Ṯ ڣゾ ᗦ⼻ₚ ảԪ ⋃Ԧാা ⱎ⧊⋦ ঃ ᚦᚪ

⁾ ڣゾᗦ‪Ԧ ↖ܮ ₷Ṫ⋦஺ ֖೿ ᘢ ᬾ ₮ఊ.

Fig. 5Ỷᩂ ᘚἒ∢஺ ᑚ἖ ᪺౺Ԧ ᰊ⃋ൂ WB-PBGA ⱎ

⧊⋦⁾ ףῖỶᩂ஺ ⁆἖ ᪺౺Ԧ ᰊ⃋ൂ ⱎ⧊⋦⁾ ףῖὦ ఒዒ ⱎ⧊⋦ ᚦᚪ⁾ ἚⱣ╣ₚ PCB ᚦᚪỶ ᝪ⺚ ᧧టギ

₷ֲ ₢Ớাᩂ K◚℧⁢ᆂ ᰒ⺂ ڣゾ ᗦ⼻ₚ ᕂᨃൂ ֩

 ᘢ ᬾ ₮ఊ. ᪺౺ ᘢ⁾ Ԫᩓᑚ௒೪ ఊኚֲ া⧦াᩂ ⱎ

⧊⋦ ᚦᚪآ PCB ᚦᚪ⁾ Ἒᗦ⼻ ╎ₚᆂ ₞⹾ἒ ᪺౺ ᘢ

Ỷ ᧧ట⺂ Kఎᗦ⼻ₚ ᕂᨃ⺂ ֩ Ṳ ᬾ ₮ఊ. ⁆἖ ᪺

౺⁾ ףῖὦ஺ ᔾదᆂ ṪႾᆂ ᘢᆃ⺂ ڣゾᗦ‪ኢ ᕂᨃᰂ

⧊؆ ₮⁢᎖, ὎೪Ԧ સṪ⋦᎚ ᗦ⼻ₚ ⋃Ԧ⹾ἒ K◚℧

⁢ᆂ Ԫᩓᑚ௒ ᧒ₚ⁾ Ԫ׏ₚ ↧Ṫ⋦⋦ዲ, ὎೪Ԧ ౺ સ Ṫ⅞ᩂ 125^oCԦ ാ᎚ ڣゾ ᗦ⼻ₚ ܯ׏ギ Ὢ⽺ാ஺ ⼪᧧

 ᘢ ᬾ ₮ఊ. זᆆ℧⁢ᆂ ⁆἖ ᪺౺Ԧ ᰊ⃋ൂ ⱎ⧊⋦ὦ ᑚ἖ ᪺౺Ԧ ᰊ⃋ൂ ⱎ⧊⋦⁾ ὎೪ᗦ⽺Ỷ ద⺂ K◚℧₞

ᗦ⼻ ֖೿⁦ ᧧టギ ఊኚֲ া⧦৒ఊ.

3.1. ᪺౺Ԧ ᰊ⃋ൂ WB-PBGA ⱎ⧊⋦ ז⺏◚⁾ ڣゾᗦ⼻

֖೿

Fig. 6⁦ ⁆἖آ ᑚ἖ ᪺౺Ԧ PCBỶ ᰊ⃋ൂ WB-PBGA ⱎ⧊⋦ ז⺏◚Ỷ ద⹾ἒ V ᗦ‪ Ԫᩓᑚ௒Ỷᩂ ᔾ೪◚ ➏

⁾ ∷ᰒᩆ ๖Ⴂ ỡỚ৞ ڣゾᗦ‪⁾ ᚪⴒኢ া⧦৞ఊ.

⁆἖ ᪺౺ὦ ᑚ἖ ᪺౺Ԧ ᰊ⃋ൂ WB-PBGA ⱎ⧊⋦஺ ԧ

὎೪ ఎתỶᩂ ᧧టギ ఊኞ ᗦ⼻ ֖೿ া⧦৚؆ ₮ఊ.

Fig. 6(a)Ỷᩂ ᘚἒ∢؆ ₮஺ ⁆἖ ᪺౺ ᰊ⃋ WB-PBGA ⱎ⧊⋦⁾ ףῖỶᩂ஺ 75^oC⁾ ὎೪Ỷᩂ ڣゾᗦ⼻⁦ ֖⁾

ᕂᨃാ⋦ ṰṾ⁢᎖, ὎೪Ԧ ౺ ᧧ᯟ⹾ἒ 100^oCԦ ാ᎚ Ꮦ

๏ ᘛ⺏⅂⁾ ἚⱣ╣תᬾԦ ᔾ೪◚ ➏⁾ ἚⱣ╣תᬾᘚఊ

⦒ᓦᆂ ᔾ೪◚ ➏ₚ ঃা஺ ᚦᚪݲ⋦஺ ‪ᆂ ᘢᆃ⺂ ڣ ゾᗦ⼻(∩)ₚ ᕂᨃാỮ؆, ➏ₚ Ử஺ ᚦᚪ⁦ ᔾద⁾ ڣゾ ᗦ⼻ₚ ₢Ớাᩂ ‪ᆂ ڣ஺(∪) ֖೿ ᘚἒ ܞዢآ Կₚ S₶ᆂ ڒᚦᄒ⋪ ᗦ⼻(~)ₚ ₢Ớ৒⁲ ᘢ ᬾ ₮ఊ. ₚᄒ

⺂ ᗦ⼻⁦ ὎೪Ԧ 125^oCᆂ ᧧ᯟ⺆ ๲ݲ⋦ K◚℧₞ ڣゾ ᗦ‪⁾ ⦒ݖዲ ⋃Ԧ⹾ἦ؆ K◚℧₞ ᗦ⼻ ֖೿⁦ ᗦ⹾⋦

ṰṾఊ. ὎೪ 125^oCỶᩂ 60ᚪ ೿Ṯ⁾ ⁆⋦ᰂԪ ೿Ṯ ڣ ゾ ᗦ⼻ₚ ảԪ ⋃Ԧാ؆ ⱎ⧊⋦ ঃ ᚦᚪₚ 〾Ớ ὒႢԦ ᩂ S₶ ⼻⨂ ڣゾₚ ౺ ⠊⋦஺ ֩⁢ᆂ া⧦৒⁢া ܞ ἧ

⻋⁦ ⦒⋦ ṰṾఊ.

Fig. 6(b)Ỷᩂ ᘚἒ∢؆ ₮஺ ᑚ἖ ᪺౺ ᰊ⃋ WB-PBGA ⱎ⧊⋦⁾ ףῖỶᩂ஺ ὎೪Ԧ ᧧ᯟ⺎Ỷ ๖Ⴂ ➏ ⴒ⺎⺂

ⱎ⧊⋦ ᚦᚪآ PCB ᚦᚪ⁾ ἚⱣ╣תᬾ ╎ₚᆂ ₞⹾ἒ ⦖ ڣゾᗦ‪Ԧ ᕂᨃാỮ⁢᎖ 100^oCݲ⋦ ὎೪Ԧ ⋃ԦൎỶ

Fig. 5. Representative fringe patterns of the WB-PBGA Package assembly with SAC305 solder joints.

๖Ⴂ ڣゾᗦ‪Ԧ ⋃Ԧ⹾ἦ⁢া ὎೪Ԧ ᧧ᯟ⺎Ỷ ๖Ⴂ ڣ ゾᗦ‪⁾ ⋃Ԧ⁎⁦ Զ᪲⹾ἦఊ. ܞᄒা ὎೪Ԧ 125^oCݲ

⋦ ᧧ᯟ⹾᎚ ᪺౺ ᘢ⁾ ז⺏ᅋ ả⽺ὦ Ꮦ๏ ᘛ⺏⅂⁾ ᑢ

ᩗ❾ ᗦ⽺ᆂ ₞⺚ ڣゾᗦ‪Ԧ ᧧టギ Զ᪲⹾஺ ⼪᧧ ᘚ ἦఊ. ⯟ギ ➏ₚ ‪❾⺂ ᚦᚪݲ⋦஺ ᪺౺ ᘢ⁾ ז⺏ᅋ ả

⽺ὦ ⦖ ἚⱣ╣תᬾ⁾ ╎ₚᆂ ₞⹾ἒ ‪ᆂ ᘢᆃ⺂ ⼻⨂

⁾ ڣゾ ᗦ⼻ ᘚἦ؆ া፞⋦ ᚦᚪỶᩂ஺ 100^oCₚ⹾⁾

὎೪Ỷᩂὦ Կ⁦ ṪႾᆂ ᘢᆃ⺂ ڣゾ ᗦ⼻ ᘚἒ S₶ ⼻

⨂⁾ ڣゾ ᗦ⼻ ᕂᨃᰂ⡖⁢᎖ ⱎ⧊⋦ ঃఎ⁾ ⚂ద ڣ ゾᗦ‪(warpage)஺ ᧧టギ Զ᪲⹾஺ ⼪᧧ ᘚἦఊ. ὎೪ 125^oCỶᩂ 60ᚪ ೿Ṯ⁾ ⁆⋦ᰂԪ ⿪Ỷ஺ ⯟ᗪ⺂ ᗦ⼻ ⼻

⨂⁾ ᗦ⽺஺ ỬỮ؆ S₶ᆂ ڣ஺ ᗦ⼻ₚ ảԪ ౺ ⋪⺯ാ

Ữఊ.

Ẅ⁾ זآỶᩂ ᘚ஺ ᔺὦ Կₚ ὎೪ᗦ⽺Ỷ ๖ኞ ⁆἖

᪺౺ ᰊ⃋ WB-PBGA ⱎ⧊⋦ὦ ᑚ἖ ᪺౺ ᰊ⃋ ⱎ⧊⋦⁾

ᗦ⼻֖೿⁦ దఎギ ⦖ ╎ₚኢ ᘚἦ⁢᎖ ₚ஺ ᪺౺ ⃒ᇲ

⁾ ╎ₚዲ⁢ᆂ஺ ᩊᎫ⹾ݖ Ớᅛఊ. ₢ᔾ℧⁢ᆂ ⁆἖ ᪺

౺ὦ ᑚ἖ ᪺౺⁾ ῏⁛ ὎೪஺ ⦖ ╎ₚԦ ₮⁢᎖ ܞỶ ๖ Ⴂ ᧒῏⹾஺ Ꮦ๏ ᘛ⺏⅂ὦ ⱎ⧊⋦ ݖⰶ⁾ ݖת℧ ᑢᩗ

❾೪ ఒႢ⋮ ᬾ ₮ఊ. ๖Ⴂᩂ ᘞ ઢᑞỶᩂ஺ ₚᄒ⺂ ╎ₚ

Ԧ ₮⁲ ؆ᅊ⹾ἒ ⁆἖ ᪺౺ ᰊ⃋ ⱎ⧊⋦ὦ ᑚ἖ ᪺౺ ᰊ⃋ ⱎ⧊⋦⁾ ᗦ⼻֖೿ ᰊ⻾℧⁢ᆂ ⺚ᩃ⹾؆ ᝪٶ⹾

ἦఊ.

3.2. WB-PBGA ⱎ⧊⋦⁾ ڣゾᗦ⼻ ֖೿

3.1Ỷᩂ ⁆἖ ᪺౺ ᰊ⃋ ⱎ⧊⋦ὦ ᑚ἖ ᪺౺ ᰊ⃋ ⱎ⧊

⋦஺ ὎೪⁾ ᗦ⽺Ỷ ద⹾ἒ ᧧టギ ఊኞ ڣゾ ᗦ⼻ ֖೿

 ᘚἦఊ. ₚᄒ⺂ ╎ₚ஺ ᪺౺ ᘢ⁾ ἚⱣ╣תᬾ, ⧪ᩗת

ᬾ ท ݖת℧ ⯟ᩗₚ ఊኚݖ ๲ᑞ₢ ᬾ೪ ₮⋦ዲ ⱎ⧊⋦

₶◚⁾ ὎೪Ỷ ๖ኞ ᗦ⼻ ֖೿೪ ఊኚݖ ๲ᑞ₢ ᬾ೪ ₮ ఊ. ₚኢ ⰲṫ⹾ݖ ‪⹾ἒ PCBỶ ᰊ⃋ാ⋦ Ṱ⁦ ⱎ⧊⋦

₶◚⁾ ὎೪Ỷ ๖ኞ ᗦ⼻ ֖೿ ᑚṪᄮ Ԫᩓתኢ ₚ῏

⹾ἒ ⺚ᩃ⹾ἦఊ. Fig. 7⁦ ᪺౺ ᘢₚ PCBỶ ᰊ⃋ാ⋦ Ṱ

⁦ ⁆἖ ᪺౺ὦ ᑚ἖ ᪺౺ WB-PBGA ⱎ⧊⋦Ỷ ద⹾ἒ ᔾ೪◚ ➏⁾ ∷ᰒᩆ ๖Ⴂ ỡỚ৞ ڣゾᗦ‪ ᚪⴒኢ া

⧦৞ఊ. ڣゾᗦ‪஺ ԧ ὎೪ ఎתỶᩂ ݖᆃ⺂ V ᗦ‪ኢ

া⧦৚஺ Ԫᩓᑚ௒ᆂᚦ⩖ ỡỚⅲఊ. ܞዢỶᩂ ᘚ஺ ᔺὦ Կₚ PCBԦ ז⺏ാ⋦ Ṱ⁦ ףῖỶ೪ ൶ ⱎ⧊⋦⁾ ڣゾ ᗦ⼻ₚ ᧧టギ ఊኚֲ া⧦৒⁢᎖ K◚℧₞ ڣゾ ᗦ⼻⁾

⼻⨂஺ ԧԧ⁾ ᪺౺ ᘢₚ ז⺏ൂ ⱎ⧊⋦ ז⺏◚⁾ ףῖ

Fig. 6. Bending displacement distributions along the center line of the WB-PBGA package assemblies due to temperature change.

Fig. 7. Bending displacement distributions along the center line of

the WB-PBGA packages due to temperature change.

ὦ⁆᧒⹾ֲা⧦৒ఊ

.

Fig. 7(a)

ᔾ೪◚➏ףתᆂ➏ₚ₮஺ᚦᚪآᔺދᚦᚪ⁾ڣゾ

؇ኆₚఒႢᗦ؇ℶₚᕂᨃ⹾ἦఊ

.

๏ᘛ⺏⅂ὦ➏⁾ἚⱣ╣תᬾ⁾╎ₚᆂ₞⺚Ꮦ๏ᘛ⺏

⅂Ԧ౺ዴₚⱣ╣⹾ᓦᆂ‪ᆂᘢᆃ⺂ڣゾᗦ⼻ₚᕂᨃ

ാỮ؆

,

Ꮦ๏ᘛ⺏⅂⁾ἚⱣ╣תᬾᘚఊ⦒ᓦᆂṪႾᆂᘢᆃ⺂ڣ ゾᗦ⼻ₚা⧦৒ఊ

.

125

C

ᝪᩆ⼻֖೿ᘚₚ⋦Ṱ؆ᗦ‪Ԧ⋃Ԧ⹾ἦ⁢াK◚℧

₞ڣゾᗦ‪⁾⦒ݖ஺᧧టギ₷ֲা⧦৒ఊ

. Fig. 7(b)

ᩂᘚἒ∢؆₮஺ᑚ἖᪺౺ⱎ⧊⋦⁾ףῖ὎೪Ԧ

100

C

ݲ⋦஺➏ₚ₮஺ᚦᚪỶᩂ஺ڣゾₚ₢Ớা⋦Ṱ؆ܞ ᔺދ⏣Ỷ஺ṪႾᆂᘢᆃ⺂ڣゾᗦ⼻ₚা⧦৒⁢᎖

,

἖᪺౺ⱎ⧊⋦ὦᝪٶ⹾ἦ๲᧧టギ⦖ڣゾᗦ‪Ԧ ᕂᨃ⹾ἦఊ

.

125

C

100

C

آ஺ᔾదᆂ‪ᆂᘢᆃ⺂ڣゾᗦ⼻ₚᕂᨃാỚ؆὎Ỷ ᩂ஺ⱎ⧊⋦ז⺏◚Ԧ᧧ట⺂ᝪᩆ⼻֖೿¹⁴⁾ᘚἦఊ

.

⁆἖᪺౺ⱎ⧊⋦ὦᑚ἖᪺౺ⱎ⧊⋦Ԧ

PCB

ാ⋦Ṱ⁦᧧⨂Ỷᩂ὎೪Ỷ๖ኞK◚℧₞ᗦ⼻֖೿ₚ

᧧టギఊኚֲা⧦া஺֩⁦ԧⱎ⧊⋦ኢڒᩗ⹾؆₮

஺Ꮦ๏⽺⺏ᑢ༶஺ⱎ⧊⋦ݖⰶ⁾⧪ᩗתᬾὦἚⱣ╣

תᬾท⁾ݖת℧₞ᑢᩗ❾ԦԿ⋦Ṱ⁦ףῖỶ₢Ớ৆

ᬾ₮ఊ

.

‪⹾ἒԧ⃒ᇲ⁾ἚⱣ╣תᬾኢᑚṪᄮԪᩓתᰊ⻾⁢ᆂ

❇℻⹾ἦఊ

.

⺚ᩂ஺὎೪Ỷ๖ኞᗦ⼻֖೿₾ₚ⺚⹾؆ⱎ⧊⋦⁾

὎೪⯟ᩗἮ❇⺆⹪ᾺԦ₮ఊ

.

4. WB-PBGA ⱎ⧊⋦⁾ Ἒᗦ⼻ ⺚ᩃ

⁆἖᪺౺ὦᑚ἖᪺౺ⱎ⧊⋦ኢ

PCB

⺂↖֚∷ⱎ⧊⋦⁾὎೪⯟ᩗỶԦ⃋∷Ὰ⹾ֲἧ⻋

ᔞ❾஺֩⁦᪺౺ኢ῏⁛ᰂ⧊ݖ‪⺂ᰊ⃋὎೪ₚఊ

.

⃋὎೪஺⁆἖᪺౺⁾ףῖ஺

210~220

C

,

౺஺᪺౺⁾ڒᩗᑢ⋮Ỷ๖Ⴂఊኚ⋦ዲ

240~250

C

ᆂṲᅊ⅞₮ఊ

.

ⱎ⧊⋦ݖⰶ⁦ₚ὎೪Ỷגโᬾ₮ỚẢ⹾ᓦᆂ᪺౺Ỷ ๖Ⴂ℧℮⺂ⱎ⧊⋦⃒ᇲኢ᧒῏⹾஺֩ₚ∷Ὰ⹾ఊ

.

ઢᑞỶᩂ஺⁆἖᪺౺ⱎ⧊⋦ὦᑚ἖᪺౺ⱎ⧊⋦⁾Ἒ ᗦ⼻֖೿ỶԦ⃋⦖ἧ⻋ᔞ❾஺ἚⱣ╣תᬾኢᑚṪ ᄮԪᩓתỶ⁾⺚❇℻⹾؆ₚኢܢ֖ᆂᗦ⼻֖೿Ỷద

⺚⺚ᩃ⹾ἦఊ

.

4.1. WB-PBGA ⱎ⧊⋦⁾ ἚⱣ╣ תᬾ ❇℻

ᔾ೪◚ⱎ⧊⋦஺➏ỶKᅋₚ؛ܯാỚ὎೪ᗦ⽺Ԧᨃ ݖ᎚ԧ⃒ᇲช⁾ἚⱣ╣תᬾ╎ₚᆂ₞⹾ἒᩂᆂఊኞ ᝪ⁎ᆂᗦ⼻⹾ֲാ᎖ₚᆂ₞⺚ⱎ⧊⋦Ԧڣゾᗦ⼻ท

⁾܆₢⹾⋦Ṱ⁦ᗦ⼻⹾ֲൂఊ

.

⋦ኢڒᩗ⹾؆₮஺⃒ᇲ⁾ἚⱣ╣תᬾኢ❇℻⹾ݖ‪⹾

ἒ

Fig. 8

PCB

ἦఊ

.

₮ఊ

.

CTE (ppm/

C) = (3)

ἒݖᩂ∆L⁦❇℻⹾ᅊ஺ᰂⳞ৚⁾֖ዒኢা⧦৚؆

,

∆T஺὎೪⁾ᗦ⽺

,

ኢা⧦৞ఊ

.

Fig. 9

WB-PBGA

໢Ớ৞Ꮦ๏⽺⺏ᑢ⁾὎೪Ỷ๖ኞԪᩓᑚ௒∷దⶂ℧

₞֩ᘚἒ∢؆₮⁢᎖ᰃ

(3)

ᬾኢ

Fig. 10

.

WB-PBGA

⁾ףῖᏖ๏⽺⺏ᑢ⁾ἚⱣ╣תᬾ஺ả

12.9 ppm/

C

❇℻ാỮ؆

,

WB-PBGA

100

C

8.3 ppm/

C

100

C

๖ႢἚⱣ╣תᬾԦܯ׏⹾ֲ⋃Ԧാ஺⼪᧧ᘚἦఊ

.

ᄖ⼪᧧⁦

Fig. 7(b)

∆L∆T∆U

--- 10× ⁶ 1 2fs

--- ∆N∆L∆T--- 10× ⁶

=

Fig. 8. Parts of molding compound and substrate for measuring coefficients of thermal expansion.

Fig. 9. Representative fringe patterns of a part of molding compound according to the temperature.

⋦⁾

125

C

₞ₚാ஺֩⁢ᆂⰶఎൂఊ

. 100

C

ⱎ⧊⋦⁾Ꮦ๏⽺⺏ᑢ⁾ἚⱣ╣תᬾԦᑚ἖᪺౺ⱎ⧊⋦

⁾Ꮦ๏⽺⺏ᑢ⁾ἚⱣ╣תᬾᘚఊ౺⦒ֲ❇℻ാỮఊ

.

Fig. 11

WB-PBGA

⁾ⱎ⧊⋦ݖⰶἚⱣ╣תᬾኢ὎೪Ỷ๖Ⴂা⧦৚Ữఊ

.

ⱎ⧊⋦ݖⰶ⁾ἚⱣ╣תᬾ஺๖ᆂᰂⳞዲชỚ❇℻⹾

⋦ṰṾ؆ⱎ⧊⋦⁾Ԫᩓᑚ௒∷ఊኞ⃒ᇲ⁾ἧ⻋ᕁ

⋦Ṱ஺ঃᚦᚪ⁾Ԫᩓᑚ௒ኢ⺚ᩃ⹾ἒỡỚ৚Ữఊ

.

⧊⋦ݖⰶ⁾ףῖả

20.5 ppm/

C

Ữ⁢᎖⁆἖᪺౺ὦᑚ἖᪺౺⁾ⱎ⧊⋦⁾ⱎ⧊⋦ݖⰶ ἚⱣ╣תᬾ஺⦖╎ₚኢᘚₚ⋦ṰṾఊ

. PCB

἖᪺౺آᑚ἖᪺౺ⱎ⧊⋦Ỷᩂ೿₢⺂

PCB

ἒᰊ⃋⹾ἦ⁢᎖

,

Fig. 12

⧦৚Ữ؆ᰃ

(3)

Fig. 13

Ỷ া⧦৚Ữఊ

.

PCB

12.1 ppm/

C

.

⁆἖᪺౺

WB-PBGA

⧊⋦ݖⰶ⁾ἚⱣ╣תᬾ╎ₚԦ᧧ద℧⁢ᆂ₷Ṫᩂڣ ゾ֖೿ₚ⦒ֲᕂᨃാ⋦ṰṾ⁢᎖

,

๏⽺⺏ᑢ⁾ἚⱣ╣תᬾ⁾╎ₚᆂ₞⹾ἒ➏ᚦᚪỶᩂ

஺ᔾదᆂڣ஺⼪᧧ₚা⧦৒ఊ

.

ῖᏖ๏⽺⺏ᑢآⱎ⧊⋦ݖⰶ⁾ἚⱣ╣תᬾ⁾╎ₚԦ⠊ ᩂ὎೪Ԧ⋃Ԧ⺎Ỷ๖Ⴂ᧧ట⺂ڣゾᗦ⼻ₚᕂᨃാỮ

⁢া

100

C

ᬾԦܯ׏⹾ֲ᧧ᯟ⹾ἒ

125

C

100

C

ᗦ⼻آ஺ᔾదᆂ‪ᆂᘢᆃ⺂ڣゾᗦ⼻ₚᕂᨃാ஺᧧ ట⺂ᝪᩆ⼻֖೿ᘚἦఊ஺֩Ṳᬾ₮ఊ

.

4.2. WB-PBGA ⱎ⧊⋦⁾ ᬾ⳯ᗦ‪ ֖೿ ᝪٶ

⁆἖᪺౺ⱎ⧊⋦ὦᑚ἖᪺౺ⱎ⧊⋦⁾ףῖᏎ൶᪺

౺ᘢỶℷ╏ൂⱎ⧊⋦ݖⰶ⁾ἚⱣ╣תᬾԦԦ⃋⦒ֲ

❇℻ാỮఊ

.

WB-PBGA

஺ఊ؆⺆ᬾ₮ఊ

.

἖᪺౺ὦᑚ἖᪺౺Ԧᰊ⃋ൂ

WB-PBGA

Ԧ

100

C

,

(U

)

Fig.

14

.

#2

ᩂᚦ⩖

#7

⋧ᩆ๖Ⴂᕂᨃ⹾஺ᬾ⳯ᕏ⻋ᗦ‪ኢⶂᰂ⹾ἦఊ

.

K◚℧₞Ᵽ╣⁦⁆἖᪺౺ᰊ⃋ⱎ⧊⋦Ԧᑚ἖᪺౺ ᰊ⃋ⱎ⧊⋦ᘚఊ⦒᎖

Fig. 14(a)

ᰊ⃋ൂ

WB-PBGA

ݖⰶₚ

PCB

⁢᎖ₚᆂ₞⺚K◚℧⁢ᆂṪႾᆂڣギ஺ᗦ⼻ₚᕂᨃ

ാỮ⁲Ṳᬾ₮ఊ

.

Fig. 10. Coefficient of thermal expansion obtained from the moiré fring patterns of the molding compounds.

Fig. 11. Coefficient of thermal expansion obtained from the moiré fring patterns of the substrates.

Fig. 12. Representative fringe patterns of a part of PCB according to the temperature.

Fig. 13. Coefficient of thermal expansion obtained from the moiré

fringe patterns of the PCB.

∷ᰒỶᩂᔺދ⏣⁢ᆂԮᬾᆃ

(-)

(+)

ఎᗦ⼻ₚᕂᨃ⹾ἦఊ஺֩ᩊᎫ⺆ᬾ₮ఊ

. Fig. 14(b)

Ỷᩂᘚ஺ᑚ἖᪺౺Ԧᰊ⃋ൂ

WB-PBGA

‪ὦ஺ᔾదᆂ

PCB

ᗦ‪Ԧ౺⦒ֲ❇℻ാỮ⁢᎖ₚᆂ₞⺚K◚℧⁢ᆂ‪ ᆂڣ஺⦖ᗦ⼻ₚᕂᨃാỮ⁲Ṳᬾ₮ఊ

.

ⱎ⧊⋦⁾ףῖ஺Ꮦ๏⽺⺏ᑢ⁾⦖ἚⱣ╣תᬾᆂ₞⹾ἒ ᘛ⃇⺂ᚪⴒኢԼ஺

U

,

⁆἖᪺౺ᰊ⃋ⱎ⧊⋦⁾ףῖ஺K◚℧⁢ᆂ܆₢⺂ڣ ゾᗦ⼻ₚ₢Ớ৒⁲ᘢᬾ₮ఊ

.

൶Ԧ⋦ⱎ⧊⋦⁾ڣゾᗦ⼻⁾╎ₚỶద⺂༶⺂Ԧ⋦

ₚ⁆ᆂ

PCB

౺⁾⧪ᩗתᬾԦ⁆἖᪺౺₞ףῖả

30.0 GPa,

౺₞ףῖả

16.6 GPa

Ԧᰊ⃋ൂ

WB-PBGA

ⱎ⧊⋦ݖⰶآ

PCB

೪Ỷ๖ኞἚⱣ╣⅂⺂⹾ἦݖ๲ᑞ⁢ᆂⰶఎൂఊ

.

᪺౺ⱎ⧊⋦⁾᪺౺ᘢ‪ṪႾ᎚᧒ₚ⁾ᬾ⳯ᕏ⻋ᗦ‪

╎Ԧ₷⋦Ṱ⁦֩⁢ᆂা⧦৒⁢া

,

ኢᘢ๲ₚᗦ‪╎஺᪺౺ᘢ⁾Kఎᗦ⼻ᕂᨃᰂ⧊ݖ ᘚఊ஺Ի◚⾲KỶ⁾⺂ᬾ⳯ᕏ⻋ᗦ‪⁾╎ₚ₞֩⁢ᆂ ⰶఎൂఊ

.

4.3. ᪺౺ ᘢ⁾ ᗦ⼻ኆ ֖೿ ᝪٶ

ᔾ೪◚ⱎ⧊⋦⁾➏ỶKᅋₚ؛ܯാỚ὎೪ᗦ⽺Ԧᨃ ݖ᎚ἚⱣ╣תᬾ╎ₚᆂ₞⹾ἒڒᩗ⹾؆₮஺ԧ⃒ᇲ ชₚᩂᆂఊኞᝪ⁎ᆂᗦ⼻⹾ֲാ᎖

,

౺ᘢỶ⁷ᅋ⋷∷ᕂᨃᰂ⡂ⰲ᪶⁾ῶ₞ₚാ೪ᆃ⺂

ఊ

.

BGA

PCB

ᚪ⁾Ἒᗦ⼻╎ₚᆂ₞⹾ἒ᪺౺ᘢỶ஺Kఎᗦ⼻ኆ

(

)

آᬾ⋧ᗦ⼻ኆ

(

)

, WB-PBGA

⧊⋦Ỷᩂ஺᪺౺ᘢ⁾Kఎᗦ⼻ኆₚⱎ⧊⋦⁾ⰲ᪶آᰆ

ᇖᩗỶ⦖ἧ⻋ᔞ➂ఊ؆Ṳᅊ⅞¹²⁾₮ఊ

. Fig. 15

Fig.

16

100

C

125

C

,

آᑚ἖᪺౺Ԧᰊ⃋ൂ

WB-PBGA

ᚦᚪ⁾ԧ᪺౺ᘢỶద⹾ἒ⳯܆ᬾ⋧ᗦ⼻ኆ

(

)

Kఎᗦ⼻ኆ

(

)

.

⁾

4

Ը⁢ᆂᚦ⩖ᰃ

(2)

.

PCB

PBGA

⁢᎚ⱎ⧊⋦ὦ

PCB

ኆₚᕂᨃ⺂ఊ

.

(

)

PCB

,

(

)

⁦∢ᆂⱎ⧊⋦ὦ

PCB

.

὎೪Ԧ

100

C

Fig. 15

Ỷᩂ⁆἖᪺౺⁾ףῖ⳯܆ᬾ⋧ᗦ⼻ኆ

(

)

ᘢỶᩂ֖⁾ᝪᯝ⺂Ը⁢ᆂỡỚⅲ஺ಖ

,

ז⺏◚⁾ڣゾᗦ⼻ₚ֖⁾ᕂᨃാ⋦ṰṪ⳯܆℧⁢ᆂᝪ ᯝ⺂Ը⁾ᬾ⋧ᗦ⼻ኆₚᕂᨃാỮݖ๲ᑞₚఊ

.

ኆ⁾ԸₚKఎᗦ⼻ኆ⁾Ըᘚఊ᧧టギ⦖֩⁢ᆂা⧦

৒⋦ዲᬾ⋧ᗦ⼻ኆ⁾దᚦᚪ⁦᪺౺⃒ᇲ⁾ἚⱣ╣Ỷ⁾

⺂₶⁆ᗦ⼻ኆₚ᎖

,

24 ppm/

o

C,

80

C

0.192%

⁾ᬾ⋧ᗦ⼻ኆ⁦₶⁆ἚⱣ╣Ỷ⁾⺂ᗦ⼻ኆₚఊ

.

⁷ᅋᕂᨃᰂ⧒ᬾ₮஺ݖת℧₞ᬾ⋧ᗦ⼻ኆ⁦Ṫ∢₷

ֲᕂᨃൂ֩Ṳᬾ₮ఊ

.

#3

ᘢỶᩂᔺދ⏣⁢ᆂԮᬾᆃℶ╎⳯܆ᬾ⋧ᗦ⼻ኆₚ⋃Ԧ

⹾஺֩ᘢᬾ₮஺ಖ

,

⋦ὦ

PCB

⁢ᆂڒ᪳⹾஺᪺౺ᘢỶᗦ⼻ₚ⋃Ԧ⹾ἦݖ๲ᑞₚఊ

.

Fig. 14. Horizontal displacement distributions across each solder

balls of WB-PBGA package assembly at the temperature

of 100

C.