Mounting structure and motor
AssigneePanasonic Corporation
InventorsKenji Kondo, Masahito Hidaka, Koji Kuyama, Yutaka Kamogi
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Abstract
A mounting structure 1 in which an electronic component 5 is surface-mounted with solder 4 to a wiring substrate 2 is disclosed. The solder is Sn—Ag—Bi—In-based solder containing 0.1% by weight or more and 5% by weight or less of Bi, and more than 3% by weight and less than 9% by weight of In, with the balance being made up of Sn, Ag and unavoidable impurities. The wiring substrate has a coefficient of linear expansion of 13 ppm/K or less in all directions. Thus, it is possible to realize a mounting structure using lead-free solder and for which the occurrence of cracks in a solder joint portion due to a 1000-cycle thermal shock test from −40 to 150° C. has been suppressed.
Claims6
A mounting structure in which an electronic component is surface-mounted with Sn—Ag—Bi—In-based solder onto a wiring that is formed in a predetermined pattern on a wiring substrate,
- the Sn—Ag—Bi—In-based solder comprises 0.1% by weight or more and 5% by weight or less of Bi, and more than 3% by weight and less than 9% by weight of In, the balance being made up of Sn, Ag and unavoidable impurities,
- the wiring substrate has a coefficient of linear expansion of 13 ppm/K or less in all directions,
- a solder resist having a smaller thickness than the wiring is formed on the same surface of the wiring substrate on which the wiring is formed;
- and
- the solder resist is made of a resin composition containing a thermosetting epoxy resin as a main component and containing an acrylic resin as an additive.
Dependencies are inferred from the claim text.