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With continuous concerning on the toxic of element Pb, Pb-free solder was gradually used to replace traditional Sn-Pb solder. However, during the transition period from Sn-Pb to Pb-free solder, mixing of Sn-Pb and Pb-free is inevitable occurred in certain products, and in China where Sn-Pb solder was still used extensively in certain areas especially. Correspondingly, understanding reliability of Sn-Pb solder joints was very important, and further studies were needed.

Thermal shock test between −55°C and 125 °C was conducted on Sn-37Pb solder bumps in the BGA package to investigate the microstructure evolution and the growth mechanism of interfacial intermetallic compound (IMC) layer. The effects of thermal shock on the mechanical property and fracture behavior of Sn-37Pb solder bumps were discussed.

Pb-rich phase was coarsened and voids were increased at first; Pb-rich phase was refined and voids were decreased secondly with the increase of thermal shock cycles; the shear strength of solder bumps was slightly decreased after thermal shock, but was back up to 73.67MPa at 2,000 cycles; interfacial IMCs of solder bumps was from typical scallop-type into smooth, the composition of IMCs was from Cu₆Sn₅ into Cu₆Sn₅ and Cu₃S_n after thermal shock with 1,500 and 2,000 cycles; 20.0 per cent of solder bumps at 1,500 cycles and 9.5 per cent of solder bumps at 2,000 cycles were failure respectively.

Compared with the board level test method, the impact shear test for the single solder bump is more convenient and economical and is actively pursued by the industries. The shear strength of solder bumps was slightly decreased after thermal shock, but was back up to 73.67 MPa at 2,000 cycles; 20.0 per cent of solder bumps at 1,500 cycles and 9.5 per cent of solder bumps at 2,000 cycles were failure.

By using ethnographic data and family interviews from eight families in Taipei, Taiwan, this paper aims to delineate how multigenerational families implement parents’ child-rearing values, and how these strategies vary by social class. The primary focus is the child’s mother and her relationship with other family members. I ask the following question: How does a mother in a three-generation family implement her ideal parenting values for her child while being encumbered by the constraints of her parents-in-law? Additionally, how does this intergenerational dynamic vary with family socioeconomic status? To conceptualize this process in such a complex context, I argue that we must understand parenting behaviors as acts of “doing family” and “intensive mothering.”

From 2008 to 2009, I conducted a pilot survey in two public elementary schools to recruit the parents of sixth-grade students. All eight cases of multigenerational families in this paper were selected randomly after being clustered by the parent’s highest education level and family income levels. This paper utilized the mothers’ interviews as the major source to analyze, while the interviews of other family members served as supplementary data.

Two cases, Mrs Lee and Mrs Su’s stories, were selected here to illustrate two distinctive approaches toward childrearing in multi-generational families. Results indicate that white-collar mothers in Taiwan hold the value of concerted cultivation and usually picture the concept of intensive mothering as their ideal image of parenthood. Yet, such an ideal and more westernized child-rearing philosophy often leads to tensions at home, particularly between the mother and the mother-in-law. Meanwhile, blue-collar mothers tend to collaborate with grandparents in sharing childcare responsibilities, and oftentimes experience friction over child discipline in terms of doing homework and material consumption.

Via this analysis of three-generation families in Taiwan, we are able to witness the struggle of contemporary motherhood in East Asia. This paper foregrounds the negotiations that these mothers undertake in defining ideal parenting and the ideal family. On the one hand, these mothers must encounter the new parenting culture, given that the cultural ideal of concerted cultivation has become a popular ideology. On the other hand, by playing the role of daughter-in-law, they must negotiate within the conventional, patriarchal family norms.