engineered to deliver alpha...engineered to deliver uniform thickness and flatness during high speed...

PRIVILEGED AND CONFIDENTIAL MATERIALS

ALPHA®

SACX™ 0307 HASL

Product Guide

the product:Engineered to deliver uniform thickness and flatness during high speed processing while contributing to improved assembly reliability

2 PRIVILEGED AND CONFIDENTIAL MATERIALS

Lead-Free HASL• Cookson Electronics have developed a low cost, high

reliability Lead-Free alloy that is suitable for the HASL process• Alloy is part of the SACX™ Plus family

• The alloy minimizes copper dissolution and delivers vary flat pads even for the smallest components

• Flatter pads than traditional Tin Lead.


Key attributes of SACX™ 0307 HASL• Alloy contains all the primary

constituents of standard SACX™Plus

• Exceptional wetting performance

• Low drossing• High mechanical reliability• Low Ag (low cost)

• Requires lower overall processing temperatures

• Higher Nickel content than standard SACX™Plus

• Decreases copper erosion rate

• Improves joint appearance slightly


Reliability

Tin Whiskers

Stress Testing - thermal cycling

Stress Testing – joint strength

Creep Strength (time to failure)

HardnessElongation %

Tensile Strength (M-Pa)

Coefficient of Thermal Expansion

Thermal ConductivityDensity / Specific Gravity

Key Considerations

•Small amounts of Bismuth (<3%) improves the fatigue resistance of Lead-Free solder alloys. This is due to the solid solubility of Bismuth in Tin that results in a hardening of the alloy.

•Silver improves the fatigue resistance of Lead-Free alloys as it forms IMC Ag3Sn with the tin, these hard platelets increase the fatigue resistance.


Why do silver bearing alloys exhibit high thermal fatigue resistance?

High Ag alloys contain more Ag3Sn intermetallic compound (IMC) in the bulk solder matrix resulting in greater mechanical strength and higher resistance to stress during temperature cycling

The bulk solder matrix of Ag-free alloys (ie. SN100C) are weaker

and less resistant to stressSn-Cu-Ni sample

High Cycle Fatigue by Gunther Grossman

Key Considerations


Reliability dataKey Considerations

Silver contributes to alloy strength while also helping to keep it ductile – improving it’s ability to absorb and recover

from mechanical stress

Silver contributes to alloy strength while also helping to keep it ductile – improving it’s ability to absorb and recover

from mechanical stress

The Ag3Sn platelets also make the alloy hard

Vibration test, High Cycle Fatigue by Gunther Grossman

Charpy Impact Test


Dross Reduction• All SACX® alloys, including SACX™ 0307 HASL,

contain an additive that reduces drossing rates

Huawei Technical Study

Note: Alloy C is SACX™ Plus 0807 – this alloy has the same amount of antioxidant as SACX™ 0307 HASL


“In our test, SACX™ Plus 0307 HASL exhibits a slightly better copper dissolution rate than SN100C” – Serigroup -Belluno, Italy

3rd Party Copper Dissolution Test Results


SACX™ Plus 0307 HASL• This product has been in the market since early 2006. • There are nearly 20 customers that have been using SACX® HASL

for at least one year.

• They have been using SACX™ Plus 0307 HASL in their machines since the middle of 2006 (they offer sub-contract services for the finishing of boards)• They have released reports on the performance of the alloy.

We have been working closely with leading HASL machine manufacturers


Case Study 1 PENTAGAL Chemie und Maschinenbau GmbH

Bochum, Germany


HASL Equipment and SettingsPENTA AUTOMATIC® Vertical Leveling System

Test Conditions


SACX™ Plus 0307 HASL

Evaluation Findings“This alloy was very easy to

use and showed a remarkable wide process window concerning process temperature and alloy composition. Even at the lower end of the temperature window the leveling and brightness of the alloy was very satisfactory.”

“The good wetting performance of this solder alloy resulted in very smooth surfaces which gave a semi glossy appearance.”


Other Findings…• Uneven copper surfaces were coated evenly

with SACX™ Plus 0307 HASL alloy. Min thickness at the knee 2 µm.

> 2 µm


• Maximum copper erosion measured - 4µm.

Other Findings…

Maximum erosion observed - 4µm


• Copper levels are easy to maintain by daily precipitation of Cu6Sn5IMC

• Reduce the temperature to just under liquidus and remove the crystals that precipitate.

Other Findings…


Case Study 2 Circuit Engineering Marketing Company (CEMCO)

Hampshire, UK


HASL Equipment and SettingsCEMCO Quicksilver Vertical

Leveling System

• Bath temperature: 260°C• Immersion time: 4 seconds• Air Knife pressure: 30 PSI on the

front : 30 PSI on the rear.• Air knife temperature: 280°C• Immersion speed: 751 mm/s• Remove speed: 547 mm/s


Flatness of Pads• Test conducted to measure the flatness of pads.• Tests show that the SACX HASL alloy has overall

greater flatness than Sn/Pb.• SACX suitable as a drop in replacement for current

Sn/Pb process.

SACX HASL Sn63/Pb37


Front ‘Vertical’ Features Measured.


Front ‘Vertical’ Features Analysis

• Much flatter deposits than SnPb (2-3 µm vs. >7-10 µm w/ SnPb)

• Good Thickness Control

• Low Std. Deviation

• Low Range


Average comparison of all locations. Solder deposits

average under 6 µm.

Comparison of the thickness with all the locations

0

5

10

15

20

25

30

35

40

QFP SMT 1 SMT2 PTH

thic

knes

s ( m

icro

ns)

Cu

Solder

IMC

Additional flatness data on different test

board


SACX™ Plus 0307HASL Cosmetics vs. SN100C

At solder pot temperatures below 265ºC

SN100C exhibits

dewetting and a grainy

surface finish

At solder pot temperatures below 265ºC

SN100C exhibits

dewetting and a grainy

surface finish

260º C

255º C

255º C

260º C

SACX® HASL pad coverage is complete and finishes are smooth

at lower pot temperatures

SACX® HASL pad coverage is complete and finishes are smooth

at lower pot temperatures

Both alloys produce smooth, complete finishes at solder pot temperatures

of 265º C and higher.


Other Performance AttributesSpread Testing

Conclusion – Similar spreading behavior between the two alloys

Print SAC305 based no-clean solder paste on HASL pads

Wetting Speed and Force

Conclusion – In this test SACX™

Plus 0307 HASL exhibits slightly faster wetting speed than the SN100C alloy


General Customer Value Propositions for all Alpha Products

• Consistent Product Performance Globally• Manufacturing Lot Trace-ability• High Reliability Products• Access to Application Laboratories• Solder Scrap Value Recovery• Global OEM / EMS Company

Relationships


SACX™Plus 0307 HASL Potential Sources of Value

• Improved Reliability– Contributes to increased Drop Shock Resistance vs Higher Ag alloys– Contributes to increased Thermal Fatigue Resistance vs. Ag-free SnCu

alloys (ie SN100C)– Dramatically better Cu Dissolution rates vs. SAC 305

• Higher Yields– Better wetting performance vs. Ag-free SnCu alloys (ie SN100C)

delivering lower SMD related defects and better hole fill.– Uniform, flat pads for improved paste printing and lower SMD related

defects• Reduced Cost of Ownership

– Reduced dross rates vs SAC305 and many other low-Ag and Ag-free alloys

– Compatible with most popular Pb-free alloys– Lower processing temperatures than Ag-free SnCu alloys– Lower cost of metals versus industry standard SAC 305– Long shelf life (1-2 yrs) of plated assemblies

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