A method of joining a metal-ceramic substrate having metalization on at least one side to a metal body by using a metal alloy is disclosed. The metal body has a thickness of less than 1.0 mm, and the metal alloy contains aluminum and has a liquidus temperature of greater than 450° C. The resulting metal-ceramic module provides a strong bond between the metal body and the ceramic substrate. The resulting module is useful as a circuit carrier in electronic appliances, with the metal body preferably functioning as a cooling body.

To improve a TCT characteristic of a circuit substrate. The circuit substrate comprises a ceramic substrate including a first and second surfaces, and first and second metal plates respectively bonded to the first and second surfaces via first and second bonding layers. A three-point bending strength of the ceramic substrate is 500 MPa or more. At least one of L1/H1 of a first protruding portion of the first bonding layer and L2/H2 of a second protruding portion of the second bonding layer is 0.5 or more and 3.0 or less. At least one of an average value of first Vickers hardnesses of 10 places of the first protruding portion and an average value of second Vickers hardnesses of 10 places of the second protruding portion is 250 or less.

According to the present invention, there is provided a copper/ceramic bonded body including: a copper member made of copper or a copper alloy; and a ceramic member made of silicon-containing ceramics, the copper member and the ceramic member being bonded to each other, in which a maximum indentation hardness in a region is set to be in a range of 70 mgf/μm.sup.2 or more and 150 mgf/μm.sup.2 or less, the region being from 10 μm to 50 μm with reference to a bonded interface between the copper member and the ceramic member toward the copper member side.

A sintered body includes a crystal grain containing silicon nitride, and a grain boundary phase. If dielectric losses of the sintered body are measured while applying an alternating voltage to the sintered body and continuously changing a frequency of the alternating voltage from 50 Hz to 1 MHz, an average value ε.sub.A of dielectric losses of the sintered body in a frequency band from 800 kHz to 1 MHz and an average value ε.sub.B of dielectric losses of the sintered body in a frequency band from 100 Hz to 200 Hz satisfy an expression |ε.sub.A−ε.sub.B|≤0.1.

An electric circuit board includes an insulating substrate, a metal plate, and a brazing material with which the insulating substrate and the metal plate are joined together. The metal plate has a side surface over which recessed portions are scattered. The side surface of the metal plate has lines in regions around the recessed portions. The metal plate is made of copper or a copper alloy. The brazing material has a side surface that is continuous with the side surface of the metal plate. The brazing material is a silver-copper brazing alloy. A ratio of copper on the side surface of the brazing material is higher than a copper component ratio of the silver-copper brazing alloy.

A sintered body includes a crystal grain containing silicon nitride, and a grain boundary phase. If dielectric losses of the sintered body are measured while applying an alternating voltage to the sintered body and continuously changing a frequency of the alternating voltage from 50 Hz to 1 MHz, an average value ε.sub.A of dielectric losses of the sintered body in a frequency band from 800 kHz to 1 MHz and an average value ε.sub.B of dielectric losses of the sintered body in a frequency band from 100 Hz to 200 Hz satisfy an expression |ε.sub.A−ε.sub.B|≤0.1.

When a laminate of a plurality of different materials including a metal plate is bonded in a pressurized and heated state, a first pressurizing member in which a first metal foil/a carbon sheet or a ceramic sheet/a graphite sheet are laminated in this order is arranged so that the first metal foil is in contact with a surface of the first metal plate of the laminate, the first metal foil is made of a material that does not react at a contact surface of the first plate member and the first metal foil when heating, and a product of a Young's modulus (GPa) and a thickness (mm) of the first metal foil is 0.6 or more and 100 or less, so that a good bonded body can be manufactured by evenly pressurizing the laminate and foreign substances can be restrained from adhering to the surface of the laminate.

A method for the joining of ceramic pieces with a hermetically sealed joint comprising brazing a layer of joining material between the two pieces. The ceramic pieces may be aluminum nitride or other ceramics, and the pieces may be brazed with Nickel and an alloying element, under controlled atmosphere. The completed joint will be fully or substantially Nickel with another element in solution. The joint material is adapted to later withstand both the environments within a process chamber during substrate processing, and the oxygenated atmosphere which may be seen within the interior of a heater or electrostatic chuck. Semiconductor processing equipment comprising ceramic and joined with a nickel alloy and adapted to withstand processing chemistries, such as fluorine chemistries, as well as high temperatures.

A method for manufacturing a power module substrate includes a first lamination step of laminating a ceramic substrate and a copper sheet through an active metal material and a filler metal having a melting point of 660° C. or lower on one surface side of the ceramic substrate; a second lamination step of laminating the ceramic substrate and an aluminum sheet through a bonding material on the other surface side of the ceramic substrate; and a heating treatment step of heating the ceramic substrate, the copper sheet, and the aluminum sheet laminated together, and the ceramic substrate and the copper sheet, and the ceramic sheet and the aluminum sheet are bonded at the same time.

The present invention provides a power module substrate including an insulating substrate, a circuit layer which is formed on one surface of the insulating substrate, and a metal layer which is formed on the other surface of the insulating substrate, in which the circuit layer has a first aluminum layer made of aluminum or an aluminum alloy which is bonded to the insulating substrate and a first copper layer made of copper or a copper alloy which is bonded to the first aluminum layer by solid-phase diffusion, the metal layer has a second aluminum layer made of aluminum or an aluminum alloy, and a relationship between a thickness t.sub.1 of the circuit layer and a thickness t.sub.2 of the second aluminum layer of the metal layer satisfy t.sub.1<t.sub.2.