Balver Zinn Josef Jost GmbH & Co.KG

CobarSolder paste SCAN-Ge 071

Content

Solder paste alloy Melting range Soldering properties Reliability: adding Ni+Ge

Reduces intermetallic Cu3SnFiner crystalline structureReduce Cu leachingAnti-oxidant

low Ag contentDrop test reliabilityCreep rate

Solder powder

100 microns

SCAN-Ge 071 – X F3+

Alloy

Powder type

Flux type

Powder types:X = Type 3 (25 – 45 microns)H = Type 4 (20 – 38 microns)

Solder Powder Particle Shape: Spherical

Melting point (range) - DSC

SCAN-Ge 071 = Sn0.7%Cu1.0%Ag + 0.05%Ni + 0.005%Ge

SCAN-Ge 071 has a melting range 217-224 ºC

Wetting: SAC-Paste

Prozessierung und Zuverlässigkeit von SAC-Loten mit reduziertem SilbergehaltM. Nowottnick, Rostock, und J. Trodler, Hanau

Wetting: SAC-Paste

Prozessierung und Zuverlässigkeit von SAC-Loten mit reduziertem SilbergehaltM. Nowottnick, Rostock, und J. Trodler, Hanau

Wetting: SAC-Paste

Prozessierung und Zuverlässigkeit von SAC-Loten mit reduziertem SilbergehaltM. Nowottnick, Rostock, und J. Trodler, Hanau

Wetting on Cu-FR4 boards

SCAN-Ge 071

SAC305 Reflowed with same profile at the sametime (Profile 4 Siemens)

Good Wetting (angle)

Solder filler smooth and exhibits a good wetting.Cu pad complete covered with paste – no exposed copper

SCAN-Ge on OSP board finish:

1:200

Good Wetting

Good Wetting

Anti-tombstoning / self aligment

Before soldering –misplaced component

After soldering –component centered

SCAN-Ge on NiAg board finishDue to melting range of SCAN-Ge 071:

Impact of Ni on the IMC

Cu6Sn5 IMC

(Cu,Ni)6Sn5

At ~ 3% Ni in (Cu,Ni)6Sn5

Sn-0.7Cu+NiGe

Sn-0.7Cu

Ni decreases Cu3Sn

“Effect of Ni and Ag on Interfacial Reaction and Microstructure of Sn-Ag-Cu-Ni-Ge Lead-Free Solder”, Materials Science and Technology (2006), 135-146, H. Watanabe

IMC thickness measured after 1000 h @ 120ºC

Sn3.0Ag0.5Cu Sn2.5Ag0.5Cu0.07Ni0.01Ge

Cu3SnCu3Sn

Cu6Sn5(Cu,Ni)6Sn5

Ge anti-oxidant

Ge acts as an antioxidant and surface active agent

K Watling, A Chandler, K Nogita. A Dahle, University of Queensland, Submitted for publication

SnCuNi SnCuNiGe

15 minutes ramp up to 340 ºC 30 minutes cooling

Adding Ni+Ge reduces Cu leaching

A Study on Copper Dissolution in Liquid Lead-Free Solders Under Static and Dynamic Conditions D. Shangguan – Flextronics (APEX 2009)

Reliability drop test – low Ag

Increased ductility of lower-Ag alloys is desirable for high strain rate shock loading

Reliability drop test – Ni-content

Mechanical Properties – low Ag

iNEMI PB-FREE ALLOY ALTERNATIVES PROJECT REPORT: STATE OF THE INDUSTRY – Gregory Henshall, PH.D. Hewlett-Packard Co. Palöo Alto, CA USA

Creep Rate – low Ag

Impact of Long Term Aging of SAC Solder for Harsh Environment Applications - John L. Evans, Ph.D. Associate Director Center for Advanced Vehicle Electronics (CAVE)

Creep Rate – low Ag

Shear-Test: SAC-Paste

Prozessierung und Zuverlässigkeit von SAC-Loten mit reduziertem SilbergehaltM. Nowottnick, Rostock, und J. Trodler, Hanau

Summary

SCAN-Ge is a low Ag SAC – alloy with Ni and Ge additives

The low Ag improves the wetting Ni and Ge are added to improve properties. Ni reduces Cu3Sn growth = more reliable Ni results in finer crystalline structure Ni+Ge reduces Cu leaching Ge reduces oxidation of the powder = longer

shelf and stencil life