Effect of Solder Reflow Process Variables on the Solder Wettability of Lead Free Solder Alloys

1994 ◽  
Vol 6 (2) ◽  
pp. 20-29
Author(s):  
C. Melton
Keyword(s):  
Lead Free ◽  
Lead Free Solder ◽  
Process Variables ◽  
Reflow Process ◽  
Solder Alloys ◽  
Solder Reflow ◽  
Free Solder

Thermoplastic Optical Polymers with Lead-Free Solder Reflow Resistance for HB-LED Packaging and Assembly

2010 ◽  
Vol 2010 (1) ◽  
pp. 000156-000163
Author(s):  
Weijun Zhou ◽  
Quan Yuan ◽  
Chris Li ◽  
Stephen F. Hahn ◽  
Kurt A. Koppi ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Dimensional Stability ◽  
Moisture Absorption ◽  
Lead Free ◽  
Lead Free Solder ◽  
Optical Polymers ◽  
Reflow Process ◽  
Short Period ◽  
Solder Reflow ◽  
Free Solder

A new class of thermoplastic optical polymers made by substantially fully hydrogenating block copolymers of styrene and butadiene, known as cyclic block copolymers (CBCs), were recently discovered to exhibit lead-free solder reflow resistance with peak reflow temperature up to 260°C. This kind of behavior is uncommon for traditional thermoplastic polymers. The block copolymer design and the resulting nanostructured morphology lead to strong elastic and soft solid material characteristics for CBC, which may explain why CBCs can maintain good dimensional stability at high temperatures (i.e., above its glass transition temperature, Tg) for a short period of time such as in a solder reflow process. This hypothesis was examined by computational fluid dynamics modeling on a molded CBC lens of LUXEON K2 LED package configuration. When the CBC lens is subjected to a simulated solder reflow process, the change in physical dimension due to thermal expansion and gravity effects is predicted to be negligible. However, the residual stress in the molded lens may play a profound role on its dimensional stability. There exists a critical stress value below which no observable deformation is predicted for the CBC lens. With excellent optical transparency and good long term optical stability, low moisture absorption, and good injection moldability, CBCs is a promising class of materials for LED packaging that contributes to improved LED manufacturing economics.

scholarly journals Electrochemical migration of lead-free solder alloys in Na2SO4 environment

2017 ◽  
Author(s):  
Balint Medgyes ◽  
Sandor Adam ◽  
Lajos Tar ◽  
Vadimas Verdingovas ◽  
Rajan Ambat ◽  
...  
Keyword(s):  
Lead Free ◽  
Electrochemical Migration ◽  
Lead Free Solder ◽  
Solder Alloys ◽  
Free Solder

scholarly journals The Influences Which Constitutive Models for Lead-Free Solder Alloys in General FEA Programs Give to Accumulated Inelastic Strain Behavior

2016 ◽  
Vol 5 (4) ◽  
pp. 266-274
Author(s):  
Takeharu HAYASHI ◽  
Hirohiko WATANABE ◽  
Masaaki TAKABE ◽  
Yoshinori EBIHARA ◽  
Tatsuhiko ASAI ◽  
...  
Keyword(s):  
Constitutive Models ◽  
Inelastic Strain ◽  
Lead Free ◽  
Lead Free Solder ◽  
Solder Alloys ◽  
Strain Behavior ◽  
Free Solder

Solder Joint Reliability of Sn-Cu and Sn-Ag-Cu Lead-Free Solder Alloys Solidified on Copper Substrates with Different Surface Roughnesses

2015 ◽  
Vol 830-831 ◽  
pp. 265-269
Author(s):  
Satyanarayan ◽  
K.N. Prabhu
Keyword(s):  
Solder Joint ◽  
Solder Matrix ◽  
Lead Free ◽  
Lead Free Solder ◽  
Solder Alloys ◽  
Cu Substrate ◽  
Cu Substrates ◽  
Free Solder ◽  
Substrate Surfaces ◽  
Lead Free Solders

In the present work, the bond strength of Sn-0.7Cu, Sn-0.3Ag-0.7Cu, Sn-2.5Ag-0.5Cu and Sn-3Ag-0.5Cu lead free solders solidified on Cu substrates was experimentally determined. The bond shear test was used to assess the integrity of Sn–Cu and Sn–Ag–Cu lead-free solder alloy drops solidified on smooth and rough Cu substrate surfaces. The increase in the surface roughness of Cu substrates improved the wettability of solders. The wettability was not affected by the Ag content of solders. Solder bonds on smooth surfaces yielded higher shear strength compared to rough surfaces. Fractured surfaces revealed the occurrence of ductile mode of failure on smooth Cu surfaces and a transition ridge on rough Cu surfaces. Though rough Cu substrate improved the wettability of solder alloys, solder bonds were sheared at a lower force leading to decreased shear energy density compared to the smooth Cu surface. A smooth surface finish and the presence of minor amounts of Ag in the alloy improved the integrity of the solder joint. Smoother surface is preferable as it favors failure in the solder matrix.

Nanoindentation Characterization of Lead-free Solders and Intermetallic Compounds under Thermal Aging

2010 ◽  
Vol 2010 (1) ◽  
pp. 000314-000318
Author(s):  
Tong Jiang ◽  
Fubin Song ◽  
Chaoran Yang ◽  
S. W. Ricky Lee
Keyword(s):  
Mechanical Properties ◽  
Thermal Aging ◽  
Solder Joints ◽  
Lead Free ◽  
Small Range ◽  
Lead Free Solder ◽  
Solder Alloys ◽  
Aging Test ◽  
Free Solder ◽  
Lead Free Solders

The enforcement of environmental legislation is pushing electronic products to take lead-free solder alloys as the substitute of traditional lead-tin solder alloys. Applications of such alloys require a better understanding of their mechanical behaviors. The mechanical properties of the lead-free solders and IMC layers are affected by the thermal aging. The lead-free solder joints on the pads subject to thermal aging test lead to IMC growth and cause corresponding reliability concerns. In this paper, the mechanical properties of the lead-free solders and IMCs were characterized by nanoindentation. Both the Sn-rich phase and Ag3Sn + β-Sn phase in the lead-free solder joint exhibit strain rate depended and aging soften effect. When lead-free solder joints were subject to thermal aging, Young's modulus of the (Cu, Ni)6Sn5 IMC and Cu6Sn5 IMC changed in very small range. While the hardness value decreased with the increasing of the thermal aging time.

scholarly journals Wetting of Different Lead Free Solder Alloys During Vapour Phase Soldering

2019 ◽  
Author(s):  
Mohamed Amine Alaya ◽  
Laszlo Gal ◽  
Tamas Hurtony ◽  
Balint Medgyes ◽  
Daniel Straubinger ◽  
...  
Keyword(s):  
Vapour Phase ◽  
Lead Free ◽  
Lead Free Solder ◽  
Solder Alloys ◽  
Free Solder
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