Low-Silver Content
Solder Products
SENJU METAL INDUSTRY CO., LTD.
Low-Silver Content Solder Products
Developed for environment resource management and cost reduction
Development History of Lower Silver Content Products
W hy Low Ag Solder for Flow Soldering?
Nearly 20 years ago in Japan, Senju introduced ECO Solder as one of the industry’s first environmentallyfriendly lead-free products and by 2000 the Japan Electronics and Information Technology Industries Association (JEITA) recommended use of the Sn/Ag3.0/Cu0.5 alloy for lead-free applications. With the introduction of
the EU’s RoHS legislation in 2006, the Sn/Ag/Cu or “SAC” alloy family quickly became the global industry standard. Most alloys selected contained between 3.0~4.0% silver for the best soldering performance.
In soldering large components such as connectors and coils, stable thermal conditions often cannot be guaranteed because of heat capacity issues. Especially during flow soldering, the thermal stability of the melted solder
is critical to ensure the highest wetting performance.
More recently, due to a significant metal cost increase, the electronics industry is forced to look for new materials and methods to reduce costs while maintaining the customer’s high quality expectations.
As a result JEITA began its next generation standardization project investigating potential solutions to lower
the material costs at the same time keeping the same soldering characteristics of the current materials. In 2007,
JEITA recommended the following low silver content alloys for the next generation of flow soldering.
In accordance to the above recommendations from JEITA, Senju have developed a series of low Ag content
alloys and related process equipment in order to meet the challenge of the next generation applications.
We have developed a series of low Ag products and low Ag soldering devices for flow soldering.
■ Through hole Lifting (Solder bath temp = 255°C)
Sn/0.7Cu/0.3Ag+P
Standard Flow Soldering Low Ag Solder
M35E
・by adding 0.3% Ag better wetting than SnCu
・white surface color ensures easy inspection
eliminating reflection
・can be recycled as SnAgCu
Sn/Cu/Ni type
Sn/0.7Cu/1Ag+P
Flow Soldering low Ag Solder
M771E
Low Ag Solder Paste for Reflow Processing
・improved through hole fill by adding 1% Ag
compared to SnCu
・can be recycled as SnAgCu
Altered melting properties resulting from a reduced silver content
are a crucial issue in SMT-processes. Compared to Sn3Ag0.5Cu
alloys, using Sn-Cu alloys, Sn0,3Ag0,7Cu alloys with a higher melting
point under conventional heating profiles there is an increased risk
of incomplete molten results.
Comparing SnCuNi and other Low Ag Solders
The characteristics of SnCuNi, SAC305 and two promising Low Ag Content Alloys are compared in the charts
below.
❶ Thermal Properties ： The Low Ag Content alloys have the same solid line temp as the SAC305 at 217 deg
C, approximately 11 deg C lower than the SnCuNi solid line temperature at 228 deg
C. Increasing the Ni content may further raise the liquid line temp, with +0.05% Ni
creating a 250 deg liquid line temp, leading to potential bridging issues.
❷ Wetting Ability
： Adding Ag improves wetting. A drop in temperature, as this may occur on contact
with the board, changes the wetting time significantly. Small Ag additions improve
soldering ability and minimize bridge issues.
❸ Tensile Strength
： Ag improves tensile strength. Durability is depending on temperature changes.
Selection must be according to temperature range of the environment the final
product is to be used in.
❹ Creep Characteristics： Ag improves creep characteristics. SnCuNi solder is not suitable for products
exposed to long term stress.
DSC, µW
M705E
M771E
M35E
SnCuNi
Temperature, ℃
■ Measuring conditions
Differential scanning calorimetry
Rise in temperature: 5℃/min
Sample weight: approx. 15g
Product Solidus
Temp.
217℃
217℃
217℃
228℃
M705E
M771E
M35E
SnCuNi
＊
Peak Liquidus
Temp.
219℃ 220℃
219℃ 224℃
219℃ 227℃
230℃ 230℃<＊
dependent on Ni content
M705E
M771E
M35E
SnCuNi
Tensile strength by temperature
M705E
M771E
M35E
SnCuNi
Tensile Strength, MPa
Zero Cross Time of Flow Solder
Zero Cross Time, sec
DSC Curve of Flow Solder
■ Measuring conditions
Autograph
Stroke speed: 10mm/min (0.33%/sec)
Parallel section: 10mmφ
★Please contact sales for samples and further technical details.
1 SMIC
For best Low-Ag molten results we recommend M771.
M35
Heat resistance of
mounting components
M35：227℃
M771：224℃
M705：220℃
Solder liqidus line
Using low Ag solder paste results in a narrow
setting range for peak temperatures
M771
Low-Silver Content Solder Products
Good Workability Flux
ES-0307LS
M771-S70G / M771-SHF
Temperature, ℃
■ Fusion results at Reflow Peak
Temp. 227℃
Tight with reflow properties and heat resistance this leads to a
narrowed margin for managing processing factors.
Good Workability Solder Paste
Temperature, ℃
■ Measurement conditions
Meniscograph
Flux: rosin type liquid flux
Cu plate: 30x10x0.3mmt
M35E
Low
Ag
Good Workability Resin Cored Wire
SPARKLE ESC21 / ECOSOLDER RMA08
,
,
are trademarks of Senju Metal Industry Co., Ltd.
2 SMIC
© SMIC, 2009
■ Headquarters:
Senju Hashido-cho 23, Adachi-ku, Tokyo 120-8555, Japan TEL: (81) 3-3888-5151, FAX: (81) 3-3870-3032
http://www.senju-m.co.jp/
■ Sales Offices:
Hanamaki, Akita, Sendai, Kohriyama, Hokuriku, Suwa, Nagoya, Osaka, Hiroshima, Fukuoka, Oita and Miyazaki
■ Plants: Tochigi, Saitama, Tokyo and Hyogo
■ Laboratories: Tochigi, Tokyo
Overseas Affiliates
Europe
■ Senju Metal Europe GmbH
■ Senju Manufacturing (Europe) Ltd.
■ Senju Metal (Italia) s.r.l.
Frankfurt, Germany
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TEL. (49) 69-2980150
TEL. (420) 257-289-500
TEL. (44) 1494-526-000
TEL. (39) 0444-380789
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Great Neck, New York, USA
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TEL. (1) 516-829-5488
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TEL. (55) 19-3254-2572
Asia
■ Senju (Malaysia) Sdn. Bhd.
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■ Senju (Thailand) Co., Ltd.
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■ Senju Metal (Hong Kong) Limited.
■ Senju Solnet Metal Co., Ltd.
■ Senju Metal (Huizhou) Co., Ltd. ■ Beijing Senju Electronic Materials Co., Ltd.
■ Senju Metal (Shanghai) Co., Ltd.
■ Senju Metal (Tianjin) Co., Ltd. ■ Senju Metal Korea Co., Ltd.
■ Senju Metal Industry Co., Ltd. Korea Branch
■ Senju Metal Industry Co., Ltd. Taiwan Branch ■ Senju Metal Industry Co., Ltd. Kaohsiung Branch
Selangor, Malaysia
Selangor, Malaysia
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Printed in JapanPrinted in Japan
2013-01-WEB AQD