A copper/ceramic bonded body includes: a copper member made of copper or a copper alloy; and a ceramic member made of an aluminum oxide, wherein the copper member and the ceramic member are bonded to each other, a magnesium oxide layer is provided on a ceramic member side of an interface between the copper member and the ceramic member; and a Mg solid solution layer is provided between the magnesium oxide layer and the copper member and contains Mg in a state of a solid solution in a Cu primary phase.

A copper/ceramic bonded body includes: a copper member made of copper or a copper alloy; and a ceramic member made of an aluminum nitride, wherein, the copper member and the ceramic member are bonded to each other, and a Mg solid solution layer is provided between the copper member and the ceramic member and contains Mg in a state of a solid solution in a Cu primary phase.

A method of connecting two CMC substrates that includes providing two substrates; placing one substrate approximate to the other substrate, such that at least a portion of the two substrates overlap and define a brazing area; placing a brazing material approximate the brazing area; defining a primary raster pattern that encompasses the brazing area and a portion of the two substrates outside the brazing area; defining a secondary raster pattern that encompasses the brazing area; allowing a laser to scan the primary raster pattern to preheat the brazing area to a temperature below the brazing material's melting point; allowing the laser to scan the secondary raster pattern to heat the brazing area to a temperature that is above the brazing material's melting point; melting and allowing the brazing material to flow within the brazing area; and cooling the brazing area to form a brazed joint connecting the two substrates.

A ceramic circuit substrate having a metal plate bonded, by a bonding braze material, to at least one main surface of a ceramic substrate, wherein the bonding braze material contains, as metal components, 0.5 to 4.0 parts by mass of at least one active metal selected from among titanium, zirconium, hafnium, and niobium, with respect to 100 parts by mass, in total, of 93.0 to 99.4 parts by mass of Ag, 0.1 to 5.0 parts by mass of Cu, and 0.5 to 2.0 parts by mass of Sn; and Cu-rich phases in a bonding braze material layer structure between the ceramic substrate and the metal plate have an average size of 3.5 μm or less and a number density of 0.015/μm2 or higher. A method for producing a ceramic circuit substrate includes bonding at a temperature of 855 to 900° C. for a retention time of 10 to 60 minutes.

A metal-ceramic substrate (1) comprising an insulating layer (11) comprising a ceramic and having a first thickness (D1), and a metallization layer (12) bonded to the insulation layer (11) and having a second thickness (D2),
wherein the first thickness (D1) is less than 250 μm and the second thickness (D2) is greater than 200 μm and wherein the first thickness (D1) and the second thickness (D2) are dimensioned such that a ratio of an amount of the difference between a thermal expansion coefficient of the metallization layer (12) and a thermal expansion coefficient of the metal-ceramic substrate (1) to a thermal expansion coefficient of the metal-ceramic substrate (1)
has a value less than 0.25, preferably less than 0.2 and more preferably less than 0.15 or even less than 0.1.

A method for manufacturing active metal-brazed a nitride ceramics substrate having excellent joining strength, includes: a step of preparing a mixed raw material; a step of forming a green sheet of the mixed raw material by a tape casting method; a step of removing a binder by performing degreasing; a step of performing sintering; a step of forming an aluminum nitride sintered substrate by performing gradual cooling; and a step of printing a conductive wiring pattern with active metal paste on the aluminum nitride sintered substrate.

A copper/ceramic bonded body includes: a copper member made of copper or a copper alloy; and a ceramic member made of a silicon nitride, wherein the copper member and the ceramic member are bonded to each other, a magnesium oxide layer is provided on a ceramic member side of a bonded interface between the copper member and the ceramic member, a Mg solid solution layer is provided between the magnesium oxide layer and the copper member and contains Mg in a state of a solid solution in a Cu primary phase, and a magnesium nitride phase is present on a magnesium oxide layer side of the Mg solid solution layer.

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.

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%.