| 摘要 |
<p>There is provided a surface mounting substrate on which electronic parts are surface mounted using lead-free solder, wherein it is possible to suppress an occurrence of a crack of the electronic parts, or a crack of joint portions, caused by heat cycle stress or external stress. The surface mounting substrate is a surface mounting substrate (1) on which electronic parts (4), (5) are surface mounted using lead-free solder, wherein stress relaxation portions (11a), (11b), (16) are formed in the vicinities of joint portions of the substrate to which the electronic parts (4), (5) are joined.</p> |
