Tin whisker growth on electroplated Sn multilayers

Abstract

As one of the key reliability issues, tin whisker problem has perturbed the electronics industry for several decades. Developing an effective way to mitigate the growth of tin whiskers is of great importance. In this study, we develop a novel multilayer method through alternately plating bright Sn and matte Sn layers to control the tin whisker growth. The samples of bilayer, trilayer and quadlayer were fabricated and stored at 55°C/85 % relative humidity and room temperature to evaluate the whisker growth. Experimental results revealed that the tin whiskers tended to grow on the bilayer and trilayer samples with bright Sn as the top layer. The whiskers originated from the middle or bottom layer and broke through the top layer. Compared to the bottom layer of matte Sn, bright Sn as the bottom layer was prone to promote whisker growth, due to irregular formation of intermetallic compound. With increase of the number of Sn layers, the grain structure of bottom layer became the main factor to affect Sn whisker growth. Uniform thickness of individual Sn layers could help to reduce whisker density. Optimal Sn multilayers are obtained to be matte/bright/matte Sn and bright/matte/ bright/matte Sn with uniform thickness of individual layers.

Electrochemical tuning of capacitive response of graphene oxide

“…18 If the reduction proceeds to lower cathodic potentials, the π electron system is restored and the concentration of oxygen functional groups decays monotonically, while the electrocatalytic properties (probed using ferro/ferri-cyanide system) are improved. 18 Similar conclusions were derived by Liu et al 25 who also demonstrated a reduced charge transfer resistance with the decrease of the GO reduction potential using impedance measurements. However, despite an intensive research, there is still no consensus regarding the impact of different structural and chemical parameters on the capacitive performance of graphene-based materials.…”

Facet, Junction and Electric Field Engineering of Bismuth‐Based Materials for Photocatalysis

“…[159] This prominent enhancement of photocatalytic performance and efficient separation of photoinduced electron-hole pairs are attributed to the construction of a Z-scheme structure and reliable interfacial interaction of BiVO 4 /g-C 3 N 4 . A series of techniques, [115] nÀBi 12 O 17 Cl 2 / pÀBiOI photocatalytic oxidation of 2,4-DCP, RhB, phenol, BPA, and tetracycline hydrochloride [119] nÀSr 2 TiO 4 / pÀBi 5 O 7 I photocatalytic oxidation of MO [120] pÀBiOI/ nÀBiPO 4 photocatalytic oxidation of MO and phenol [121] pÀBiOBr/ nÀLa 2 Ti 2 O 7 photocatalytic oxidation of RhB and phenol [122] pÀBiOI/ nÀBi 2 O 2 CO 3 photocatalytic oxidation of RhB [123] pÀBiOI/ nÀgÀC 3 N 4 photocatalytic oxidation of BPA [124] nÀBiPO 4 / pÀBiOBr Photocatalytic activity for formaldehyde Oxidation; photocatalytic oxidation of RhB [125126] pÀBiOCl/ nÀBiVO 4 photocatalytic oxidation of RhB [127] pÀBiOI/ nÀBiOIO 3 photocatalytic oxidation of MB [30] pÀCuBi 2 O 4 / nÀBiWO 6 photocatalytic oxidation of MB and photocatalytic reduction of Cr 2 O 7 2À [128] pÀBiOCl/ nÀBiVO 4 photocatalytic oxidation of MO [129] pÀBi 2 O 3 / nÀBi 2 WO 6-x F 2x photocatalytic oxidation of RhB [130] pÀBiOCl/ nÀBi 2 O 2 CO 3 photocatalytic oxidation of RhB [131] pÀBi 2 O 3 / nÀBi 2 WO 6 photocatalytic oxidation of RhB and phenol [114] pÀBiOI/ nÀMnNb 2 O 6 degradation of antibiotics (TC, oxytetracycline, ciprofloxacin and doxycycline) [132] pÀBiOBr/ nÀCeO 2 photocatalytic oxidation of RhB, MB and phenol [133] pÀBiOBr/ nÀBi(C 2 O 4 ) OH photocatalytic oxidation of RhB [134] pÀBi 2 O 3 / nÀBi 2 MoO 6 photocatalytic oxidation of RhB and 2,4-DNP [135] pÀBiOBr/ nÀZnO photocatalytic oxidation of phenol [136] pÀBiOBr/ nÀBiOIO 3 photocatalytic oxidation of RhB, MB, MO and crystal violet [137] pÀBiOBr/ nÀTiO 2 photocatalytic oxidation of RhB and photocatalytic H 2 generation [138] pÀBiOI/ nÀBrÀBi 2 O 2 CO 3 photocatalytic oxidation of MO [139] pÀBiOI/ nÀBi 2 Sn 2 O 7 photocatalytic oxidation of RhB [140] pÀBiOI/ nÀSnS 2 photocatalytic oxidation of RhB [141] nÀFe 2 O 3 / pÀBiOI photocatalytic oxidation of RhB…”

Spontaneous Tin (Sn) Whisker Growth from Electroplated Tin and Lead-Free Tin Alloys Coatings: A Short Review

“…The need for lead-free electronics manufacturing has rekindled interest in the problem of tin (Sn) whiskers. Sn whisker grows spontaneously from an electrodeposited tin coating on a copper substrate at room temperature, which can lead to well-documented system failures in electronics [1][2][3][4]. Although this phenomenon was first identified and reported in the late 1940s there is still a lot of uncertainty about the detailed mechanisms of Sn whisker growth.…”