The Effect of Germanium Additions 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 on the Tin-Copper Eutectic: Sn-0.7Cu with a trace addition of Ni at a very specific level and
Germanium (Ge). The effect of Germanium additions
Ⅰ- The effect of bridge elimination The effect of bridge elimination on SN100C
SN100C makes bridge-free soldering possible even with 100pin 0.5mm pitch QFP.
100pin 0.5mm pitch QFP Wave soldering With SN100C The mechanism of bridging
Whether or not bridging occurs depends on what happens as the joint exits the wave (the “peel back” area) The mechanism of bridging
Whether or not bridging occurs depends on what happens as the joint exits the wave (the “peel back” area)
If drainage is good there is no excess solder left on the joints So there is no solder to form a bridge
The Peel-Back Solder is draining off Area the joint area back into the solder bath The mechanism of bridging
Whether or not bridging occurs depends on what happens as the joint exits the wave (the “peel back” area)
If drainage is not good there is excess solder left on the joints This excess solder forms a bridge The mechanism of 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. The mechanism of 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.
[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. Icicle test
[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） Wetting balance test equipment ・Immersion depth: 6mm （Tarutin Kester） ・Immersion speed: 4mm/s ・Immersion time: 20s ・Withdrawal speed: 2mm/s
Test piece: Oxygen free copper ring
つら Before After dipping dipping らの Icicle *High Speed Camera 長さlength Icicle MEMRECAMfx K4 （nac Image Technology., Inc. ） Icicle test
Oxygen Free Copper Ring
2.0 mm Ø ・Flux: JIS Standard Flux A, B ・Melting Temp.: 255℃ ・Immersion Depth: 6mm ・ 20mm Immersion Speed: 4mm/s ・Immersion Time: 20s ・Withdrawal time: 2mm/s
Solder Bath Icicle test
Solder alloy samples (%) Sn Pb Cu Ni P Ag Bi Ge SC SC R 0.7 system SCN R 0.7 0.05 SCN SN100C R 0.7 0.05 0.01 system SCNP R 0.5 0.05 0.05
SCA SC0.3A R 0.7 0.3 system SCAB R 0.7 0.3 0.1 SAC S3A0.5C R 0.5 3.0 system SP S37P R 37 system Test results
Flux: JIS Standard flux A 1400 1315 1206 The effect of Ni 1200 1144
m) 998 1000
μ 819 800 600 The effect of Ge 386 400 285
つららの長さ（μm） 174 200
Icicle length ( Icicle length 0
SC SCN SCAB SCNP SC0.3A S3A0.5C SN100C S37P(235℃) Sn-Cu-Ni Solderはんだ材料 alloy The effect of bridge elimination on SN100C
SN100C makes bridge-free soldering possible even with 100pin 0.5mm pitch QFP.
Ni “plus Ge” The effect of
100pin 0.5mm pitch QFP Wave soldering with SN100C The effect of Germanium additions
Ⅱ- Wetting properties Wetting test – Meniscographic method
Ｔ０ Ｔ1 Ｔ2 Ｔ3 Ｔ4 Ｔ6Ｔ7 Ｔ8 Start of Interval to Maximum force Start of resistered test wetting 2/3Fmax Immersion Zero-crossing Withdrawal Withdrawal complete commences Stages of through time Interval to completed hole soldering 2/3Fmax Total wetting Wetting rate time Maximum after zero- wetting force crossing time Zero- Component crossing time termination Fｍａｘ Fend 2/3Fｍａｘ Heating Board Board time
Wetting rate
Wetting force Immersion Incubation Cu land period period Interval to zero wetting force Wetting test – Meniscographic method
Immersion Period F Incubation Period t Wetting method – Meniscographic method
Fmax
2/ F Immersion 3 max Period F Incubation Period Zero t Crossing First Second Stage Stage Wetting Wetting 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℃ Test piece: Copper wire ・Immersion time: 10 sec. ・Immersion depth: 2 mm ・Immersion speed: 2mm/s ・Withdrawal speed: 2 mm/s Wetting properties of Sn-Cu system lead-free solder
1.0
0.5
SCNP and SCA system take longer to 0.0 start wetting after zero-crossing time. 00.511.52
ぬれ力（ｍＮ） -0.5
SCNP takes longer to start wetting. Wetting force (mN) Wetting force -1.0 Time時間(秒） (s)
ＳＮ１００Ｃ ＳＣ ＳＣＮ ＳＣＮＰ ＳＣ0.3Ａ ＳＣＡＢ Start of wetting
Ｔ０ Ｔ1 Ｔ2 Ｔ3 Ｔ4 Ｔ6Ｔ7 Ｔ8 Maximum force Start of Start of Interval to resistered wetting wetting 2/3Fmax Withdrawal Withdrawal Immersion Zero-crossing Stages of through commences completed complete time Interval to hole soldering 2/3F max Total wetting time Maximum wetting force Zero- Component crossing termination Fｍａｘ Fend time 2/3Fｍａｘ
Heating Board Board time
Wetting force Immersion Incubation Start of wetting Cu land period period Start of wetting
The disadvantage of P 0.6 0.5 0.5 0.4 0.4 0.4 0.4 0.4 0.4
0.3
0.2
0.1 ぬれ開始時間（sec） Start of wetting (s) Start of wetting 0.0 SN100C SCN ＳＣ SCNP SC0.3A SCAB Interval to zero-wetting force
Ｔ０ Ｔ1 Ｔ2 Ｔ3 Ｔ4 Ｔ6Ｔ7 Ｔ8 Maximum force Start of Start of Interval to resistered wetting wetting 2/3Fmax Withdrawal Withdrawal Immersion Zero-crossing Stages of through commences completed complete time hole soldering Total wetting time Maximum wetting force Zero-crossing Component time termination Fｍａｘ Fend 2/3Fｍａｘ
Heating Board Board time Wetting force Immersion Incubation Interval to zero Cu land time time wetting force Interval to zero-wetting force
The disadvantage of Bi 0.6 The effect of Ni 0.514 0.5 0.405 0.4 0.380 0.333 0.327 0.317 0.3
0.2 ぬれ時間（sec） 0.1
0.0 SN100C SCN ＳＣ SCNP SC0.3A SCAB Interval to zero-wetting force (s) Interval to zero-wetting Interval to 2/3Fmax
Ｔ０ Ｔ1 Ｔ2 Ｔ3 Ｔ4 Ｔ6Ｔ7 Ｔ8 Maximum force Start of Start of Interval to resistered wetting wetting 2/3Fmax Withdrawal Withdrawal Immersion Zero-crossing Stages of through commences completed complete time Interval to hole soldering 2/3Fmax Total wetting time Maximum wetting force Zero-crossing Component time termination Fｍａｘ Fend 2/3Fｍａｘ
Heating Board Board time Wetting rate Wetting force Immersion Incubation Interval to zero- Cu land time time wetting force Interval to 2/3Fmax The disadvantage of Ag
0.4 0.348
0.290 0.3 The disadvantage of P
The effect of Ge 0.2 0.183 0.130 0.116 0.125 0.1 ぬれ上がり時間（sec） Interval to 2/3Fmax (s) Interval to 2/3Fmax
0.0 SN100C SCN ＳＣ SCNP SC0.3A SCAB Total wetting time
1.4 The effect of Ni and Ge 1.203 1.2 1.153 1.000 1.0 0.905 0.849 0.860 0.8
0.6
0.4
0.2総ぬれ時間（sec）
0.0 time (s) Total wetting SN100C SCN ＳＣ SCNP SC0.3A SCAB The effect of Germanium additions
Ⅲ- The reduction of dross generation Method of measuring dross rates
1. 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 air at 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
SN100C Sn-3.0Ag-0.5Cu Sn-0.7Cu Sn-0.7Cu-0.05Ni Sn-0.7Cu-0.05Ni+Ge Dross generation
The dross generation of SN100C is half as much as that of SAC305.
120 120%
100% 100 100% 84.5% 77.1% 78.7% The effect 80 77.5 80% of Ge 65.5 59.8 61.0 60 60% 47.4% 比率（％） 36.8 40 40% Ratio (%) ドロス発生量（ｇ／時間） 20 20% Dross generation (g/hr) Dross generation
0 0% Sn-3.0Ag-0.5Cu Sn-0.7Cu Sn-0.7Cu-0.3Ag Sn-0.7Cu-0.05Ni SN100C はんだ材料
1時間当たりのドロス発生量（ｇ/時間） 比率（％） Summary of the effect of Germanium additions The effect of Germanium additions
ⅠBridge elimination
The beneficial effect of Ge on drainage combined with the beneficial effect of Ni on fluidity ensures minimum bridges.
Ⅱ Faster wetting
The Ni addition accelerates initial wetting and the Ge addition accelerates wetting after zero-crossing.
Ⅲ Reduced dross generation
The thin film that Ge forms on the surface of solder bath reduces the formation of the tin oxide that is the basis of dross.