Balver Zinn Josef Jost GmbH & Co.KG Cobar Solder paste SCAN-Ge 071 1

Content Solder paste alloy Melting range Soldering properties Reliability: adding Ni+Ge Reduces intermetallic Cu3Sn Finer crystalline structure Reduce Cu leaching Anti-oxidant low Ag content Drop test reliability Creep rate

Solder powder SCAN-Ge 071 – X F3+ Flux type Alloy Powder type Powder types: X = Type 3 (25 – 45 microns) H = Type 4 (20 – 38 microns) 100 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 Silbergehalt M. Nowottnick, Rostock, und J. Trodler, Hanau

Wetting: SAC-Paste Prozessierung und Zuverlässigkeit von SAC-Loten mit reduziertem Silbergehalt M. Nowottnick, Rostock, und J. Trodler, Hanau

Wetting: SAC-Paste Prozessierung und Zuverlässigkeit von SAC-Loten mit reduziertem Silbergehalt M. Nowottnick, Rostock, und J. Trodler, Hanau

Wetting on Cu-FR4 boards SCAN-Ge 071 SAC305 Reflowed with same profile at the same time (Profile 4 Siemens)

Good Wetting (angle) SCAN-Ge on OSP board finish: Solder filler smooth and exhibits a good wetting. Cu pad complete covered with paste – no exposed copper

Good Wetting 1:200

Good Wetting

Anti-tombstoning / self aligment SCAN-Ge on NiAg board finish Due to melting range of SCAN-Ge 071: Before soldering – misplaced component After soldering – component centered

Impact of Ni on the IMC Sn-0.7Cu Cu6Sn5 IMC Sn-0.7Cu+NiGe At ~ 3% Ni in (Cu,Ni)6Sn5 (Cu,Ni)6Sn5

Ni decreases Cu3Sn IMC thickness measured after 1000 h @ 120ºC Sn3.0Ag0.5Cu Sn2.5Ag0.5Cu0.07Ni0.01Ge Cu6Sn5 (Cu,Ni)6Sn5 Cu3Sn 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

15 minutes ramp up to 340 ºC 30 minutes cooling Ge anti-oxidant Ge acts as an antioxidant and surface active agent SnCuNi SnCuNiGe K Watling, A Chandler, K Nogita. A Dahle, University of Queensland, Submitted for publication 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 Silbergehalt M. 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