the effect of germanium additions on sn100c€¦ · the effect of bridge elimination on sn100c...

The effect of Germanium additions on SN100C

Nihon Superior Co., Ltd.

What is SN100C?

SN100C is a lead-free solder that is based onthe Tin-Copper Eutectic: Sn-0.7Cu

Germanium (Ge).

with a trace addition of Ni at a very specific leveland

Ⅰ- The effect of bridge elimination

The effect of Germanium additions

The effect of bridge elimination on SN100C

100pin 0.5mm pitch QFPWave soldering With SN100C

SN100C makes bridge-free soldering possibleeven with 100pin 0.5mm pitch QFP.

The mechanism of bridging

Whether or not bridging occurs depends on what happens as the joint exits the wave

(the “peel back” area)

The Peel-BackAreaSolder is draining off

the joint area back into the solder bath

If drainage is good there is no excess solder left on the joints

The mechanism of bridgingWhether or not bridging occurs depends on what

happens as the joint exits the wave(the “peel back” area)

So there is no solder to form a bridge

If drainage is not good there is excess solder left on the joints

The mechanism of bridgingWhether or not bridging occurs depends on what

happens as the joint exits the wave(the “peel back” area)

This excess solder forms a bridge


To study the effect of bridge elimination, the icicle test was carried out and the drainage characteristic of solder wave were confirmed.

Whether or not bridging occurs depends on what happens as the joint exits the wave (the “peel back” area)


[Results]1. The Ni addition to the Sn-Cu lead-free increases fluidity of the

solder and eliminates bridging.2. The addition of Ge to the Sn-Cu-Ni alloy to make “SN100C”

improves the drainage properties of the solder to further reduce any tendency to bridging.

Whether or not bridging occurs depends on what happens as the joint exits the wave (the “peel back” area)

To study the effect of bridge elimination, the icicle test was carried out and the drainage characteristic of solder wave were confirmed.

[Test conditions]・Test piece: Oxygen free copper ring (20mm ID, wire diameter 2.0mm）・Solder alloys: SC, SCN, SN100C, SCNP, SC0.3A, SCAB, S3A0.5C, S37P・Flux: JIS Standard flux A and B・Melting temperature: 255 ℃

（235℃ only for S37P）・Immersion depth: 6mm・Immersion speed: 4mm/s・Immersion time: 20s・Withdrawal speed: 2mm/s

つららの長さ

Test piece: Oxygen free copper ring

Before dipping

After dipping

IcicleIcicle length

Wetting balance test equipment（Tarutin Kester）

*High Speed CameraMEMRECAMfx K4（nac Image Technology., Inc. ）

Icicle test

Oxygen Free Copper Ring

・Flux: JIS Standard Flux A, B・Melting Temp.: 255℃・Immersion Depth: 6mm・Immersion Speed: 4mm/s・Immersion Time: 20s・Withdrawal time: 2mm/s

20mm

2.0 mm Ø

Solder Bath

Icicle test

Icicle test

S37P

S3A0.5C

SCAB

SC0.3A

SCNP

SN100C

SCN

SC

37RSP system

3.00.5RSAC system

0.3

0.3

Ag

0.010.050.7R

0.10.7R

0.7RSCA system

0.050.050.5R

0.050.7R

SCN system

0.7R SC system

GeBiPNiCuPbSn

Solder alloy samples (%)

Test results1315

12061144

998

819

386285

174

0

200

400

600

800

1000

1200

1400

S37P

(235

℃)

S3A0

.5C

SC0.3

A

SCAB SC

SCNP SC

N

SN10

0C

はんだ材料

つら

らの

長さ

（μ

m）

The effect of Ni

The effect of Ge

Sn-Cu-Ni

Flux: JIS Standard flux A

Icic

le le

ngth

(μm

)

Solder alloy

The effect of bridge elimination on SN100C

The effect of Ni “plus Ge”

SN100C makes bridge-free soldering possibleeven with 100pin 0.5mm pitch QFP.

100pin 0.5mm pitch QFPWave solderingwith SN100C

Ⅱ- Wetting properties


2/3Fｍａｘ

Ｔ０Ｔ2 Ｔ3 Ｔ4 Ｔ6Ｔ7 Ｔ8Ｔ1

Immersion period

Fｍａｘ

Heating time

Wet

ting

forc

e

Fend

Start of test Immersion

complete

Start of wetting

Zero-crossing time

Interval to 2/3Fmax

Maximum force resistered

Withdrawal commences

Withdrawal completedStages of through

hole soldering

Wetting rate

Incubation period

Maximum wetting force

Wetting rate after zero-

crossing time

Interval to 2/3Fmax

Component termination

Zero-crossing time

Total wetting time

Board Board

Cu land

Wetting test – Meniscographic method

Interval to zero wetting force

F

t

Wetting test – Meniscographic method

Immersion Period

Incubation Period

F

Fmax

2/3Fmax

t

Immersion Period

Incubation Period

Zero CrossingFirst Stage

Wetting

Second Stage

Wetting

Wetting method – Meniscographic method

Test conditions[Test conditions]

・Test piece: Copper wire(wire diameter 0.6mm, length 30mm)

・Solder alloys: SN100C, SC, SCN, SCNP, SC0.3A, SCAB・Flux: JIS Standard flux B (for meniscographic test)・Melting temperature: 255℃

・Immersion time: 10 sec.・Immersion depth: 2 mm・Immersion speed: 2mm/s・Withdrawal speed: 2 mm/s

Test piece: Copper wire

-1.0

-0.5

0.0

0.5

1.0

0 0.5 1 1.5 2

時間(秒）

ぬれ

力（ｍ

Ｎ）

ＳＮ１００ＣＳＣＳＣＮＳＣＮＰＳＣ0.3ＡＳＣＡＢ

SCNP takes longer to start wetting.

SCNP and SCA system take longer to start wetting after zero-crossing time.

Wetting properties of Sn-Cu system lead-free solderW

ettin

g fo

rce

(mN

)

Time (s)

2/3Fｍａｘ


Fｍａｘ

Heating time

Fend

Start of wetting

Start of wetting

Immersion complete

Start of wetting

Zero-crossing time

Interval to 2/3Fmax



Withdrawal completed


Interval to 2/3F max

Zero-crossing

time

Total wetting time

Board Board

Cu landStart of wetting

Stages of through hole soldering


Wet

ting

forc

e

Immersion period

Incubation period

Start of wetting

0.4 0.4 0.4

0.5

0.4 0.4

0.0

0.1

0.2

0.3

0.4

0.5

0.6

SN100C SCN ＳＣ SCNP SC0.3A SCAB

ぬれ

開始

時間

（se

c）

The disadvantage of P

Sta

rt of

wet

ting

(s)

2/3Fｍａｘ


Immersion time

FｍａｘFend

Interval to zero-wetting force

Incubation time

Zero-crossing time

Total wetting time

Board Board

Cu land Interval to zero wetting force



Start of wetting

Start of wetting

Interval to 2/3Fmax

Immersion complete

Zero-crossing time





Heating time

Wet

ting

forc

e

Interval to zero-wetting force

0.333 0.327

0.380

0.317

0.405

0.514

0.0

0.1

0.2

0.3

0.4

0.5

0.6


ぬれ

時間

（se

c）

The disadvantage of Bi

The effect of Ni

Inte

rval

to z

ero-

wet

ting

forc

e (s

)

2/3Fｍａｘ


FｍａｘFend

Interval to 2/3Fmax

Wetting rate

Interval to 2/3Fmax

Zero-crossing time

Total wetting time

Board Board

Cu land Interval to zero-wetting force

Start of wetting

Start of wetting

Interval to 2/3Fmax

Immersion complete

Zero-crossing time






Heating time

Wet

ting

forc

e


Immersion time

Incubation time

Interval to 2/3Fmax

0.1160.130 0.125

0.183

0.348

0.290

0.0

0.1

0.2

0.3

0.4


ぬれ

上が

り時

間（

sec

）

The effect of Ge

The disadvantage of P

The disadvantage of AgIn

terv

al to

2/3

Fmax

(s)

Total wetting time

0.849 0.860 0.9051.000

1.1531.203

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4


総ぬ

れ時

間（

sec

）To

tal w

ettin

g tim

e (s

)

The effect of Ni and Ge

Ⅲ- The reduction of dross generation


Method of measuring dross rates1. Desk-top mini-wave solder pot

・Solder capacity: 7kg・Bath dimensions: 130mm x 150mm・Nozzle dimensions: 30mm x 30mm・Fall distance from the jet outlet to the surface of the bath: 35-40mm

2. Melting temperature: 255℃

3. Precondition the bath by operating for 30minutes in airat constant pump speed.Remove the dross generated this preconditioning.Start the test with the preconditioned solder bath.

4. Collect the dross every hour for 4hours and weigh.Calculate the quantity of dross per hour for each alloy.

The images of dross

Sn-3.0Ag-0.5Cu Sn-0.7Cu Sn-0.7Cu-0.05NiSN100C

Sn-0.7Cu-0.05Ni+Ge

Dross generation

77.5

65.559.8 61.0

36.8

100%

84.5%

77.1% 78.7%

47.4%

0

20

40

60

80

100

120

Sn-3.0Ag-0.5Cu Sn-0.7Cu Sn-0.7Cu-0.3Ag Sn-0.7Cu-0.05N i SN100C

はんだ材料

ドロ

ス発

生量

（ｇ／

時間

）

0%

20%

40%

60%

80%

100%

120%

比率

（％

）

1時間当たりのドロス発生量（ｇ/時間）比率（％）

The effect of Ge

The dross generation of SN100C is half as much as that of SAC305.

Dro

ss g

ener

atio

n (g

/hr)

Rat

io (%

)

Summary of the effect of Germanium additions


ⅠBridge elimination

The beneficial effect of Ge on drainage combined with the beneficial

Ⅱ Faster wetting

The Ni addition accelerates initial wetting and the Ge addition

Ⅲ Reduced dross generation

The thin film that Ge forms on the surface of solder bath reduces the

effect of Ni on fluidity ensures minimum bridges.

accelerates wetting after zero-crossing.

formation of the tin oxide that is the basis of dross.

the effect of germanium additions on sn100c€¦ · the effect of bridge elimination on sn100c...

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