There is provided a bonded body of the invention in which a ceramic member formed of a ceramic containing Al and a Cu member formed of Cu or a Cu alloy are bonded to each other, in which a bonding portion is formed between the ceramic member and the Cu member, an active metal compound region formed of a compound containing active metal is formed on the bonded portion on the ceramic member side, and an Al concentration of the bonding portion having a thickness range of 0.5 m to 3 m from one surface of the active metal compound region on the Cu member side towards the Cu member side is in a range of 0.5 at % to 15 at %.

A method for joining, assembling, at least two parts made of silicon carbide-based materials by non-reactive brazing is provided. According to the method, the parts are contacted with a non-reactive brazing composition, the assembly formed by the parts and the brazing composition is heated to a brazing temperature sufficient to melt the brazing composition totally or at least partly, and the parts and brazing composition are cooled to that, after solidification of the brazing composition, a moderately refractory joint is formed; wherein the non-reactive brazing composition is an alloy comprising, in atomic percentages, 45% to 65% silicon, 28% to 45% nickel and 5% to 15% aluminum. A brazing composition as defined above is provided. A brazing paste, suspension comprising a powder of said brazing composition and an organic binder as well as a joint and assembly obtained the foregoing method are also provided.

In a power-module substrate unit, a circuit layer is structured by a plurality of small circuit layers; a ceramic substrate layer is structured by at least one plate; the small circuit layers are formed to have a layered structure having a first aluminum layer bonded on one surface of the ceramic substrate layer and a first copper layer bonded on the first aluminum layer by solid diffusion; a radiation plate is made of copper or copper alloy; the metal layer and the radiation plate are bonded by solid diffusion.

A method for joining ceramic pieces includes placing a layer of titanium on each of a first ceramic piece and a second ceramic piece; placing a layer of nickel on each of the layers of titanium; assembling the first ceramic piece and the second ceramic piece with the layers of nickel and the layers of titanium between the ceramic pieces; pressing the first ceramic piece and the second ceramic piece with the layers of nickel and the layers of titanium together; heating the first ceramic piece, the second ceramic piece, the layers of nickel, and the layers of titanium to a joining temperature in a vacuum; and cooling the first ceramic piece, the second ceramic piece, the layers of nickel, and the layers of titanium to create a hermetic seal between the first ceramic piece and the second ceramic piece.

A method for producing a ceramic-aluminum bonded body obtained by bonding a ceramic member and an aluminum member, the aluminum member before bonding being composed of aluminum having a purity of 99.0 mass % or higher and 99.9 mass % or lower, includes a heat treatment step of subjecting the aluminum member to a heat treatment in a range of 400 C. or higher and lower than a solidus temperature, and a bonding step of bonding the aluminum member after the heat treatment step and the ceramic member via a brazing filler material including Si.

There is provided a bonded body of the invention in which a ceramic member formed of a ceramic containing Al and a Cu member formed of Cu or a Cu alloy are bonded to each other, in which a bonding portion is formed between the ceramic member and the Cu member, an active metal compound region formed of a compound containing active metal is formed on the bonded portion on the ceramic member side, and an Al concentration of the bonding portion having a thickness range of 0.5 m to 3 m from one surface of the active metal compound region on the Cu member side towards the Cu member side is in a range of 0.5 at % to 15 at %.

A method of manufacturing power-module substrates, after bonding copper-circuit plates 30 at intervals on a ceramic plate 21 having an area in which ceramic substrates can be formed abreast, by dividing the ceramic plate 21 between the copper-circuit plates 30, in which: bonding-material layers 71 of active-metal brazing material having same shapes as outer shapes of the copper-circuit plates 30 are formed on the ceramic plate 21; temporal-stick material 72 including polyethylene glycol as a major ingredient is spread on the copper-circuit plates 30, the bonding-material layers 71 and the copper-circuit plates 30 are temporarily fixed on the ceramic plate 21 in a state of laminating with positioning by the temporal-stick material 72; and a laminated assembly thereof is pressurized in a laminating direction and heated, so that the ceramic plate and the copper-circuit plates are bonded.

A power-module substrate unit having at least one power-module substrate including one ceramic substrate, a circuit layer formed on one surface of the ceramic substrate, and a metal layer formed on another surface of the ceramic substrate, and a heat sink on which the metal layer of the power-module substrate is bonded, in which the metal layer is made of an aluminum plate having purity of 99.99 mass % or higher; the heat sink is made of an aluminum plate having purity of 99.90 mass % or lower; and the circuit layer has a stacking structure of a first layer made of an aluminum plate having the purity of 99.99 mass % or higher and being bonded to the ceramic substrate and a second layer made of the aluminum plate having the purity lower than 99.90 mass % and being bonded on a surface of the first layer.

Disclosed is provided a process for producing a bonded body by bonding a ceramic member made of a ceramic to a Cu member made of Cu or a Cu alloy, the process including: a laminating step of laminating the Cu member on a first surface side of the ceramic member via a brazing material containing Cu and a eutectic element which has a eutectic reaction with Cu, and via an active metal; and a heating step of heating the ceramic member and the Cu member which are laminated together.

A power-module substrate including a circuit layer having a first aluminum layer bonded on one surface of a ceramic substrate and a first copper layer bonded on the first aluminum layer by solid-phase-diffusion bonding, and a metal layer having a second aluminum layer made from a same material as the first aluminum layer and bonded on the other surface of the ceramic substrate and a second copper layer made from a same material as the first copper layer and bonded on the second aluminum layer by solid-phase-diffusion bonding, in which a thickness t1 of the first copper layer is 1.7 mm to 5 mm, a sum of the thickness t1 of the first copper layer and a thickness t2 of the second copper layer is 7 mm or smaller, and a ratio t2/t1 is larger than 0 and 1.2 or smaller except for a range of 0.6 to 0.8.