| 摘要 |
<p>PURPOSE:To prevent the warp of the title device due to heat by forming a composite layer consisting of materials having different thermal expansion coefficients inside a substrate. CONSTITUTION:Both surface layers 1, 2 of a substrate 6 consist of a glass epoxy plate, etc. An intermediate layer 3 is composed of a composite layer which consists of materials having different thermal expansion coefficients. As a desirable example of the layer 3, a combination of large thermal expansion coefficient difference such as combination of Al and Cu, and Sn and Ni is recommended taking the balance of warp of the substrate 6, etc., into consideration. If the layer 3 is interposed in this way, characteristic to warp larger than temperature rise can be acquired based on the principle of bimetal. According to this characteristic, it becomes possible to make a substrate warp in the opposite direction to the warp of the substrate and to compensate for the warp amount of the substrate due to heat.</p> |
