| 摘要 |
This invention provides heat-conductive materials which may receive evenly the heat as applied thereto, which have an improved heat-releasing effect, which are free from fine pores on the surfaces thereof and therefore have excellent adhesiveness to thin films of plating materials or brazing materials, which have excellent compatibility with materials to be applied thereto, such as chips or sealant resins, with respect to the thermal expansion coefficients of them, and have excellent thermal conductivity, and which may have any desired thermal expansion coefficient and thermal conductivity in accordance with the use and object of them. It also provides methods of producing the heat-conductive materials. One aspect of the heat-conductive materials is such that a two-layer sheet or three-layer sheet to be formed by previously welding under pressure a copper foil to one surface or both surfaces of a Kovar sheet followed by forming a number of small through-holes through the sheet has been welded under pressure to and integrated with one surface or both surfaces of a copper sheet as previously heated up to a temperature not lower than the recrystallizing temperature thereof with a heating device. Another aspect of them is such that a copper sheet as previously heated up to a temperature not lower than the recrystallizing temperature thereof has been welded under pressure to the lower surface of a Kovar sheet having a number of small through-holes therethrough, with a welding machine, and additionally another copper sheet has been welded under pressure to the upper surface of the same with a welding machine, all the welded sheets having been integrated together. Still another aspect of them is such that the materials of the first aspect and/or the second aspect have been laminated and integrated together. The heat-conductive materials of all the aspects have a high welding strength even though the welding of the constitutive sheets is effected at a small reduction ratio, and they may have determined thermal expansion coefficient and thermal conductivity without fluctuating the previously determined ratio of the copper exposing surface areas (through-hole areas) to the Kovar surface. <IMAGE> |
