Element-mounted board and method for manufacturing element-mounted board
An element-mounted board includes a heat-dissipating plate in which aluminum or magnesium-containing metal layers are formed on both front and back surfaces of a flat plate-shaped metal-silicon carbide complex including aluminum or magnesium, and an electronic element including a ceramic plate, which is mounted on one surface side of the heat-dissipating plate, in which a flatness of the other surface of the heat-dissipating plate is 600 μm or less.
1. An element-mounted board comprising:
a heat-dissipating plate in which aluminum or magnesium-containing metal layers are formed on both front and back surfaces of a flat plate-shaped metal-silicon carbide complex including aluminum or magnesium; and
an electronic element including a ceramic plate, which is mounted on a side corresponding to one of the front and back surfaces of the heat-dissipating plate, wherein
a flatness of another of the front and back surfaces of the heat-dissipating plate is 600 μm or less,
a thermal expansion coefficient of the heat-dissipating plate between room temperature and 400° C. is a 1 ,
a thermal expansion coefficient of the ceramic plate between room temperature and 400° C. is a 2 , and
a difference between a 1 and a 2 is 5.0 ppm K −1 or less.
2. The element-mounted board according to claim 1 , wherein
the heat-dissipating plate is substantially rectangular,
a length of a long side of the rectangle is denoted by a and a length of a short side of the rectangle is denoted by b,
a straight line connecting each midpoint of two short sides of the other of the front and back surfaces is l 1 and a straight line connecting each midpoint of two long sides of the other of the front and back surfaces is l 2 ,
a maximum distance between a point on a curve formed by the other of the front and back surfaces and l 1 is h 1 when the heat-dissipating plate is viewed in a cross-sectional view which includes l 1 and which is substantially orthogonal to the other of the front and back surfaces,
a maximum distance between a point on a curve formed by the other of the front and back surfaces and l 2 is h 2 when the heat-dissipating plate is viewed in a cross-sectional view which includes l 2 and which is substantially orthogonal to the other surface, and
h 1 /a>h 2 /b.
3. The element-mounted board according to claim 2 ,
wherein (h 1 /a)/(h 2 /b) is 1.0 or more and 1.9 or less.
4. An element-mounted board comprising:
a heat-dissipating plate in which aluminum or magnesium-containing metal layers are formed on both front and back surfaces of a flat plate-shaped metal-silicon carbide complex including aluminum or magnesium; and
an electronic element including a ceramic plate, which is mounted on a side corresponding to one of the front and back surfaces of the heat-dissipating plate, wherein
a flatness of another of the front and back surfaces of the heat-dissipating plate is 600 μm or less, and
an arithmetic mean roughness Ra of a portion of one surface of the heat-dissipating plate on which the electronic element is not mounted is 0.2 μm to 2.0 μm.
5. The element-mounted board according to claim 1 ,
wherein, when the element-mounted board is viewed from a top surface with the side corresponding to one of the front and back surfaces as the top surface, 10% to 80% of an area of the heat-dissipating plate is covered with the electronic element.
6. A method for manufacturing the element-mounted board according to claim 1 , the method comprising:
a preparing step of preparing a heat-dissipating plate in which an aluminum or magnesium-containing metal layer is formed on both front and back surfaces of a flat plate-shaped metal-silicon carbide complex including aluminum or magnesium;
a flatness adjusting step of adjusting a flatness of at least one surface of the heat-dissipating plate; and
a mounting step of mounting an electronic element including a ceramic plate on a surface on an opposite side to the one surface of the heat-dissipating plate.