Effect of Creep Properties on Pressure Induced Tin Whisker Formation

2008 ◽  
Author(s):  
Tadahiro Shibutani ◽  
Qiang Yu ◽  
Masaki Shiratori
Keyword(s):  
Whisker Formation ◽  
Tin Whisker ◽  
Creep Properties

Study on Whisker Outbreak on Thin Plating by Contact Force

2006 ◽  
Author(s):  
Takuma Yamashita ◽  
Tadahiro Shibutani ◽  
Qiang Yu ◽  
Masaki Shiratori
Keyword(s):  
Contact Force ◽  
Whisker Formation ◽  
Stress Evolution ◽  
Tin Whisker ◽  
Element Analysis ◽  
Creep Properties ◽  
Compressive Stresses ◽  
Flexible Printed Circuit ◽  
Flex Cable ◽  
Loading Tests

Tin whisker outbreaks can pose problems on FFC/FPC (flat flex cable/flexible printed circuit) connectors in electronics components. Several mechanical loading tests for investigating whisker formation have been performed, however, the mechanical implications of the results remain unclear. The purpose of this study was to clarify whether the whisker formation mechanism on connectors is due to contact force. Using the creep properties collected from nanoindentaion tests, the stress evolution in plating is extracted. The behavior of the stress evolution was investigated by finite element analysis. During the test, the axial compressive stresses increase, although stress relaxation also occurs. The effect of substrate shape is also investigated and whiskering behavior due to stress was confirmed.

Indentation Induced Tin Whisker Formation on Tin Plated Component Leads

2005 ◽  
Author(s):  
Jin Liang ◽  
Xiaodong Li ◽  
Zhi-Hui Xu ◽  
Dongkai Shangguan
Keyword(s):  
Stress Level ◽  
Quantitative Relationship ◽  
Whisker Formation ◽  
Tin Whisker ◽  
Element Analysis ◽  
Root Cause ◽  
Stress Threshold ◽  
Calculation Results ◽  
Free Transition ◽  
Metallurgical Reactions

Tin whisker formation has been a serious concern for application of pure Tin as a Pb-free component lead finish. It has been long believed that residual stress is the root cause of whisker formation. A fundamental question is if stress produced by other than the plating processing and post-plating metallurgical reactions can induce whisker formation. In this study, micro indents were made on pure Tin plated component leads to induce stress for studying stress induced whisker formation. Nano-indentation was performed to measure hardness and elastic modulus of the Tin coating layer where whiskers initiate. Scanning electron microscopy (SEM) was used to study indentation deformation mechanisms and to monitor the nucleation and growth of whiskers in-situ. In additions, finite element analysis was carried out to theoretically calculate the stress/strain distribution around the indentations. Experimental and theoretical calculation results show that whiskers form at a certain stress level. This suggests that there might exit a critical stress threshold that governs the whisker formation. It is believed that establishment of a quantitative relationship between stress level and whisker formation/growth could lead to a breakthrough in risk and reliability assessment with pure Tin application in the electronic industry and in safeguard for smooth Pb-free transition.

scholarly journals Effect of Irregular Grown Intermetallic Compounds Network on Tin Whisker Formation

2009 ◽  
Vol 12 (1) ◽  
pp. 53-61 ◽  
Author(s):  
Tadahiro Shibutani ◽  
Takuma Yamashita ◽  
Yu Qiang ◽  
Masaki Shiratori
Keyword(s):  
Intermetallic Compounds ◽  
Whisker Formation ◽  
Tin Whisker

scholarly journals Preliminary Study of Electrical Current Stressing on Tin Whisker Formation

2019 ◽  
Vol 551 ◽  
pp. 012096 ◽  
Author(s):  
Noor Zaimah Mohd Mokhtar ◽  
Mohd Arif Anuar Mohd Salleh ◽  
Aimi Noorliyana Hashim
Keyword(s):  
Electrical Current ◽  
Whisker Formation ◽  
Tin Whisker ◽  
Current Stressing ◽  
Preliminary Study

Lead-Free Solder/Gold Metallization Interdiffusion in Electronic Interconnects – Challenges and their Control

2008 ◽  
Author(s):  
Nausha Asrar
Keyword(s):  
Solder Joint ◽  
Coefficient Of Thermal Expansion ◽  
Void Formation ◽  
Lead Free ◽  
Gold Content ◽  
Lead Free Solder ◽  
Whisker Formation ◽  
Tin Whisker ◽  
Free Solder ◽  
Gold Metallization

Abstract While considerable amount of researches and investigations have been made on lead-free solder joint reliability, limited number of literatures are available on the effect of gold content on lead-free solder joint performance. The challenges of lead-free solder/gold metallization interdiffusion during high temperature application/test are: gold embrittlement, intermetallics growth, void formation, and tin-whisker formation. Tin whiskers causing system failures in earth and space-based applications have been reported. This paper illustrates a few case histories of such challenges. The results confirmed that the synergistic effects of void formation, intermetallic compounds formation due to the thick gold plating, and coefficient of thermal expansion mismatch between organic and ceramic substrates resulted in brittle fracture of the solder joint. The tin whisker formation was attributed to the compressive stress in the tin solder material, which was caused by diffusion of the end-cap metallization, formation of intermetallics, and thermal cycling of the soldered components.

Tin Whiskers on Discrete Components: The Problem

2002 ◽  
Author(s):  
Jocelyn P. Siplon ◽  
Gary J. Ewell ◽  
Eric Frasco ◽  
Tom Gibson ◽  
Jay A. Brusse
Keyword(s):  
Critical Analysis ◽  
Whisker Growth ◽  
Nucleation And Growth ◽  
Tin Whiskers ◽  
Whisker Formation ◽  
Electronic Components ◽  
Tin Whisker ◽  
Tin Coating ◽  
First Report ◽  
Conformal Coating

Abstract This paper discusses the issues of tin whisker growth on discrete electronic components. It presents both a critical analysis of existing published documents on tin whisker nucleation and growth and a summary of very recent experiments that provide further understanding of the potential means of whisker formation mitigation. Many of the proposed techniques for reducing the likelihood of whisker formation are inadequate, including control of the immediate underplating material, use of conformal coating, regulating the thickness of the tin coating, use of matte tin electroplating, and annealing or fusing of the tin layer. They likely reduce the incidence of nucleation or growth but do not provide guaranteed protection from lack of whisker formation. The first report of tin whiskers on electronic components dates back to 1946 [16]. Since that time whisker-related problems have been reported consistently. Today the concern is for the of increased number of whisker-related problems due to circuit geometry reductions, lower application voltages and the probability of more suppliers (rapidly) introducing pure tin plated alternatives to comply with pending Pb-free legislation.

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