| abstract |
Provided is a heat transfer member which has high heat dissipation, has small anisotropy of heat conductivity, and is excellent in reliability. A first surface layer including the insulating material A, a second surface layer including the insulating material A, and an intermediate layer including the insulating material B disposed between the first surface layer and the second surface layer; The first boron nitride sintered body in which the degree of orientation of the hexagonal boron nitride primary particles is 0.6 to 1.4, and the insulating material A impregnates the first boron nitride sintered body. A thermosetting resin composition, wherein the insulating material B has a second boron nitride sintered body in which the degree of orientation of the hexagonal boron nitride primary particles is 0.01 to 0.05; And a second thermosetting resin composition impregnated in the boron sintered body. Here, the degree of orientation is determined according to I.P. O. P. (The Index of Orientation Preference). O. P. Is calculated by the following equation. I. O. P. = (I100 / I002) par. / (I100 / I002) perp. Here, (I100 / I002) par. Is the strength ratio of the surface measured along a direction parallel to the thickness direction of the boron nitride sintered body, and is (I100 / I002) perp. Is the intensity ratio of the surface measured along the direction perpendicular to the thickness direction of the boron nitride sintered body, I100 represents the intensity of the X-ray diffraction line of the (100) surface, and I002 represents the intensity of the (002) surface. It shows the intensity of the X-ray diffraction line. |