PROBLEM TO BE SOLVED: To provide: a lead-free solder containing solder paste composition capable of suppressing the development of cracking in a solder joint portion and an electronic component electrode separation phenomenon by the solder joint portion even in an environment of receiving a harsh cold shock cycle and a vibration load; a solder joint body structure formed by using the composition; and an electronic circuit board having the solder joint body structure.SOLUTION: A solder paste composition comprises: a lead-free solder alloy and a flux, the lead-free solder alloy containing 2 to 4 mass% of Ag, 1 mass% or less of Cu, and 1.5 to 3 mass% of Bi, a reminder thereof being substantially Sn, the flux containing synthetic resin, a thixotropic agent, an activator, and a solvent, and an adhesive force of a flux residue formed by the flux being not less than 0.2 N/mmafter being subjected to 2000 cycles of a cold shock test with one cycle set as -40 to 125°C/30 minutes.SELECTED DRAWING: Figure 1
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机译：解决的问题：提供一种包含无铅焊锡膏的焊膏组合物，即使在受到严寒的环境下，该焊膏组合物也能够抑制焊点的开裂的发展和通过焊点的电子部件电极分离现象。冲击周期和振动负荷;通过使用该组合物形成的焊点主体结构;解决方案：焊膏组合物包括：无铅焊料合金和助熔剂，所述无铅焊料合金包含2-4质量％的Ag，1质量％以下需要说明的是，Cu为1.5质量％，Bi为1.5质量％〜3质量％时，基本为Sn，含有合成树脂，触变剂，活化剂和溶剂的助熔剂，由该助熔剂形成的助焊剂残渣的附着力没有提高。经受2000次冷冲击试验后的循环速度小于0.2 N / mm，其中一个循环设定为-40至125°C / 30分钟。图1
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