In a copper-ceramic bonded body of the present invention, at a bonding interface of a copper member and a ceramic member, there are formed a nitride compound layer containing one or more nitride forming elements selected from Ti, Nb, Hf, and Zr, and an Ag—Cu eutectic layer, in order from the ceramic member side, the thickness of the nitride compound layer is 0.15 μm or more and 1.0 μm or less, an intermetallic compound phase formed of an intermetallic compound that contains the nitride forming element and Si is present between the copper member and the ceramic member, and Cu and Si are present at the grain boundary of the nitride compound layer.

The present invention relates to a copper ceramic substrate incorporating a ceramic carrier, and a copper layer joined to a surface of the ceramic carrier, wherein the copper layer incorporates at least one first layer, which faces the ceramic carrier and has an average first grain size, and a second layer, which is arranged on the face of the copper layer facing away from the ceramic carrier and has an average second grain size, the second grain size being smaller than the first grain size.

A method is provided for producing an insulating circuit substrate with a heat sink including an insulating circuit substrate and a heat sink, the insulating circuit substrate including a circuit layer and a metal layer that are formed on an insulating layer, and the heat sink being bonded to the metal layer side. The method includes: an aluminum bonding layer forming step of forming an aluminum bonding layer formed of aluminum or an aluminum alloy having a solidus temperature of 650° C. or lower on the metal layer; and a heat sink bonding step of laminating a copper bonding material formed of copper or a copper alloy between the aluminum bonding layer and the heat sink and bonding the aluminum bonding layer, the copper bonding material, and the heat sink to each other by solid phase diffusion bonding.

A method of manufacturing a ceramics-metal bonded body according to the present invention is a method of manufacturing a ceramics-metal bonded body in which a metal layer is bonded to at least one surface of a ceramics substrate, and comprises: a groove-forming step of forming a groove extending across a bonding region of a ceramics substrate to which a metal layer is bonded; and a bonding step of, after the groove-forming step, forming a metal layer by stacking, in the bonding region of the ceramics substrate, a metal plate of an aluminum or aluminum alloy with a thickness of less than or equal to 0.4 mm, via an Al—Si based brazing material foil, and bonding the metal plate to the bonding region by heating while applying load in a stacking direction.

A bonded body is formed to configured to join a ceramic member formed of a Si-based ceramic and a copper member formed of copper or a copper alloy, in which, in a joint layer formed between the ceramic member and the copper member, a crystalline active metal compound layer formed of a compound including an active metal is formed on the ceramic member side.

An insulated circuit board having a ceramic substrate, a circuit layer on which a circuit pattern is formed and that is bonded to one surface of the ceramic substrate, and a metal layer bonded to the other surface of the ceramic substrate. The circuit layer has a first circuit layer that is bonded to the ceramic substrate and is made of aluminum and a second circuit layer that is bonded to the upper surface of the first circuit layer and is made of copper, the metal layer has a first metal layer that is bonded to the ceramic substrate and is made of aluminum and a second metal layer that is bonded to the upper surface of the first metal layer and is made of copper, and the thicknesses of the first circuit layer and the first metal layer are each 0.2 mm or more and 0.9 mm or less.

In a silicon nitride substrate including a silicon nitride sintered body including silicon nitride crystal grains and a grain boundary phase, a plate thickness of the silicon nitride substrate is 0.4 mm or les, and a percentage of a number of the silicon nitride crystal grains including dislocation defect portions inside the silicon nitride crystal grains in a 50 μm×50 μm observation region of any cross section or surface of the silicon nitride sintered body is not less than 0% and not more than 20%. Etching resistance can be increased when forming the circuit board.

A power module substrate according to the present invention is a power module substrate in which a copper sheet made of copper or a copper alloy is laminated and bonded onto a surface of a ceramic substrate (11), an oxide layer (31) is formed on the surface of the ceramic substrate (11) between the copper sheet and the ceramic substrate (11), and the thickness of a AgCu eutectic structure layer (32) is set to 15 m or less.

A bonded body of the present invention includes a ceramic member formed of ceramics and a Cu member formed of Cu or a Cu alloy. In a bonding layer formed between the ceramic member and the Cu member, an area ratio of a Cu.sub.3P phase in a region extending by up to 50 m toward the Cu member side from a bonding surface of the ceramic member is equal to or lower than 15%.

To provide a method of manufacturing power module substrate board at high productivity and a ceramic-copper bonded body in which warps are reduced. In a bonded body-forming step, a circuit layer-forming copper layer consisting of a plurality of first copper layers is formed by arranging and bonding a plurality of first copper boards on a first surface of a ceramic board, and a metal layer-forming copper layer consisting of a second copper layer with a smaller arrangement number than that of the first copper layers is formed by bonding a second copper board having a larger planar area than that of the first copper board and a smaller thickness than that of the first copper board so as to cover at least two of adjacent substrate board-forming areas on a second surface of the ceramic board among the substrate board-forming areas partitioned by the dividing groove.