| 摘要 |
<p>PURPOSE:To prevent a substrate from producing thermal stress and make a device of better radiating characteristics, by joining the substrate on a board of composite structure which consists of metal of good heat conductivity at the lower side and metal with almost equal rate of linear expansion as that of module substrate at the lower side. CONSTITUTION:A module substrate 2, where a strip circuit pattern 7 is attached to the surface of ceramic plate, is brazed on an upper board made of Kovar or the like. Each basic circuit element is bonded and a grounding strip 10 is connected. A submodule 8 made like this is joined on a lower board 6 of nonoxide copper plate via a low-temperature brazing material 11 adhered at the bottom and sides of board 5. And then, a metal cap 4 is, for instance, LASER- welded on the board 5 and sealed by joining. Constituting the material of boards 5, 6 like this and providing the buffer layer composed of brazing material at the sides of board 5 better the radiation and prevent the substrate 2 from cracking caused by thermal stress as well.</p> |
