Abstract: The present invention provides a silicon nitride circuit board in which metal plates are attached on front and rear sides of a silicon nitride substrate having a three-point flexural strength of 500 MPa or higher, wherein assuming that a thickness of the metal plate on the front side is denoted by t1, and a thickness of the metal plate on the rear side is denoted by t2, a numerical relation: |t1?t2|?0.30 mm is satisfied, and a warp is formed in the silicon nitride substrate so that the silicon nitride substrate is convex toward the metal plate on one of the front side or the rear side; and warp amounts of the silicon nitride substrate in a long-side direction and a short-side direction both fall within a range from 0.01 to 1.0 mm. It is preferable that a longitudinal width (L1) of the silicon nitride substrate falls within a range from 10 to 200 mm, and a transverse width (L2) of the silicon nitride substrate falls within a range from 10 to 200 mm.

Abstract: 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.

Abstract: A ceramic/copper circuit board of an embodiment includes a ceramic substrate and first and second copper plates bonded to surfaces of the ceramic substrate via bonding layers containing active metal elements. In cross sections of end portions of the first and second copper plates, a ratio (C/D) of an area C in relation to an area D is from 0.2 to 0.6. The area C is a cross section area of a portion protruded toward an outer side direction of the copper plate from a line AB, and the area D is a cross section area of a portion corresponding to a right-angled triangle whose hypotenuse is the line AB. R-shape sections are provided at edges of upper surfaces of the first and second copper plates, and lengths F of the R-shape sections are 100 ?m or less.

Abstract: An electronic component module has a circuit board in which metal plates are bonded to both surfaces of a ceramic substrate, and an electronic component that is bonded to at least one surface of the metal plate and is operable at least 125° C. The electronic component is bonded to the metal plate via a brazing material layer having a higher melting point than a operating temperature of the electronic component.

Abstract: An insulation sheet made from silicon nitride comprising: a sheet-shaped silicon-nitride substrate which contains ?-silicon-nitride crystal grains as a main phase; and a surface layer which is formed on one face or both front and back faces of surfaces of the silicon-nitride substrate and is formed from a resin or a metal which includes at least one element selected from among In, Sn, Al, Ag, Au, Cu, Ni, Pb, Pd, Sr, Ce, Fe, Nb, Ta, V and Ti. A semiconductor module structure using the insulation sheet made from silicon nitride.

Abstract: An insulation sheet made from silicon nitride comprising: a sheet-shaped silicon-nitride substrate which contains ?-silicon-nitride crystal grains as a main phase; and a surface layer which is formed on one face or both front and back faces of surfaces of the silicon-nitride substrate and is formed from a resin or a metal which includes at least one element selected from among In, Sn, Al, Ag, Au, Cu, Ni, Pb, Pd, Sr, Ce, Fe, Nb, Ta, V and Ti. A semiconductor module structure using the insulation sheet made from silicon nitride.

Abstract: A ceramic/copper circuit board of an embodiment includes a ceramic substrate and first and second copper plates bonded to surfaces of the ceramic substrate via bonding layers containing active metal elements. In cross sections of end portions of the first and second copper plates, a ratio (C/D) of an area C in relation to an area D is from 0.2 to 0.6. The area C is a cross section area of a portion protruded toward an outer side direction of the copper plate from a line AB, and the area D is a cross section area of a portion corresponding to a right-angled triangle whose hypotenuse is the line AB. R-shape sections are provided at edges of upper surfaces of the first and second copper plates, and lengths F of the R-shape sections are 100 ?m or less.

Abstract: A ceramic-metal composite includes a ceramic substrate, an active metal brazing alloy layer, and a metal plate bonded to the ceramic substrate through the active metal brazing alloy layer disposed therebetween. The active metal brazing alloy layer contains a transition metal that is at least one element selected from Group-8 elements specified in the periodic table. According to the above configuration, the following composite and device can be provided: the ceramic-metal composite that exhibits high bonding strength, heat cycle resistance, durability, and reliability even if the ceramic-metal composite is used in a power module and a semiconductor device including the ceramic-metal composite.

Abstract: An electronic component module 1 has a circuit board 2 in which metal plates 5 and 7 are bonded to both surfaces of a ceramic substrate 3, and an electronic component 9 that is bonded to at least one surface of the metal plate 5 and is operable at least 125° C. The electronic component 9 is bonded to the metal plate 5 via a brazing material layer 8 having a higher melting point than a operating temperature of the electronic component 9.

Abstract: An electronic component module 1 has a circuit board 2 in which metal plates 5 and 7 are bonded to both surfaces of a ceramic substrate 3, and an electronic component 9 that is bonded to at least one surface of the metal plate 5 and is operable at least 125° C. The electronic component 9 is bonded to the metal plate 5 via a brazing material layer 8 having a higher melting point than a operating temperature of the electronic component 9.

Abstract: An insulation sheet made from silicon nitride comprising: a sheet-shaped silicon-nitride substrate which contains ?-silicon-nitride crystal grains as a main phase; and a surface layer which is formed on one face or both front and back faces of surfaces of the silicon-nitride substrate and is formed from a resin or a metal which includes at least one element selected from among In, Sn, Al, Ag, Au, Cu, Ni, Pb, Pd, Sr, Ce, Fe, Nb, Ta, V and Ti. A semiconductor module structure using the insulation sheet made from silicon nitride.

Abstract: Problem is to provide a ceramic-metal composite and a semiconductor device that exhibits high bonding strength, heat cycle resistance, durability, and reliability even if the ceramic-metal composite is used in a power module. A ceramic-metal composite includes a ceramic substrate, an active metal brazing alloy layer, and a metal plate bonded to the ceramic substrate through the active metal brazing alloy layer disposed therebetween. The active metal brazing alloy layer contains a transition metal.

Abstract: In the production of a ceramic substrate (1) with a level difference (3), a surface of a fired substrate obtained by firing of a ceramic green sheet is honed to form the level difference (3). Alternatively, a level difference is first formed through processing of a ceramic green sheet, laminating of a ceramic green sheet, or the like, and thereafter the ceramic green sheet is fired to obtain a fired substrate (ceramic substrate) (1) with a level difference (3).

Abstract: An electronic component module 1 has a circuit board 2 in which metal plates 5 and 7 are bonded to both surfaces of a ceramic substrate 3, and an electronic component 9 that is bonded to at least one surface of the metal plate 5 and is operable at least 125° C. The electronic component 9 is bonded to the metal plate 5 via a brazing material layer 8 having a higher melting point than a operating temperature of the electronic component 9.

Abstract: A thermoelectric conversion module (10) comprises first and second electrode members (13, 14), and thermoelectric elements (11, 12) arranged between the electrode members (13, 14). The thermoelectric elements (11, 12) are made of a half-Heusler material and are electrically and mechanically connected to the first and second electrode members (13, 14) via bonding parts (17). The bonding parts (17) include a bonding material which contains at least one selected from Ag, Cu and Ni as a main component and at least one of active metal selected from Ti, Zr, Hf, Ta, V and Nb in a range from 1 to 10% by mass.

Abstract: The present invention provides a silicon nitride ceramic substrate composed of a silicon nitride sintered body in which maximum size of pore existing in grain boundary phase of the sintered body is 0.3 &mgr;m or less, and having a thermal conductivity of 50 W/mK or more and a three point bending strength of 500 MPa or more, wherein a leak current is 1000 nA or less when an alternative voltage of 1.5 kV-100 Hz is applied to a portion between front and back surfaces of the silicon nitride sintered body under conditions of a temperature of 25° C. and a relative humidity of 70%. According to the above structure of the present invention, there can be provided a silicon nitride ceramic substrate capable of effectively suppressing a leak current generation when the above substrate is assembled into various power modules and circuit boards, and capable of greatly improving insulating property and operative reliability of power modules in which output power and capacity are greatly increased.

Abstract: The present invention provides a ceramic circuit board comprising: a ceramic substrate and a metal circuit portion bonded to at least one main surface of the ceramic substrate; wherein each of ratios of Ra1/Ra2 and Ra2/Ra1 is 1.5 or less in which a surface roughness in terms of arithmetical average surface roughness Ra in arbitral one direction of the ceramic substrate is Ra1 while a surface roughness Ra in a direction normal to the one direction of the ceramic substrate is Ra2, and a breakdown voltage of the ceramic substrate is 20 kV/mm or more. According to the above structure of the present invention, there can be provided a ceramic circuit board having an excellent heat-cycle resistance and bending strength characteristics without impairing a heat radiating property, and capable of increasing an operating reliability as electronic device.

Abstract: The present invention provides a ceramic circuit board comprising: a ceramic substrate and a metal circuit plate bonded to the ceramic substrate through a brazing material layer; wherein the brazing material layer is composed of Al—Si group brazing material and an amount of Si contained in the brazing material is 7 wt % or less. In addition, it is preferable to form a thinned portion, holes, or grooves to outer peripheral portion of the metal circuit plate. According to the above structure of the present invention, there can be provided a ceramic circuit board having both high bonding strength and high heat-cycle resistance, and capable of increasing an operating reliability as electronic device.

Abstract: The present invention provides a silicon nitride ceramic substrate composed of a silicon nitride sintered body in which maximum size of pore existing in grain boundary phase of the sintered body is 0.3 &mgr;m or less, and having a thermal conductivity of 50 W/mK or more and a three point bending strength of 500 MPa or more, wherein a leak current is 1000 nA or less when an alternative voltage of 1.5 kV-100 Hz is applied to a portion between front and back surfaces of the silicon nitride sintered body under conditions of a temperature of 25° C. and a relative humidity of 70%. According to the above structure of the present invention, there can be provided a silicon nitride ceramic substrate capable of effectively suppressing a leak current generation when the above substrate is assembled into various power modules and circuit boards, and capable of greatly improving insulating property and operative reliability of power modules in which output power and capacity are greatly increased.

Abstract: The present invention provides a ceramic circuit board comprising: a ceramic substrate and a metal circuit portion bonded to at least one main surface of the ceramic substrate; wherein each of ratios of Ra1/Ra2 and Ra2/Ra1 is 1.5 or less in which a surface roughness in terms of arithmetical average surface roughness Ra in arbitral one direction of the ceramic substrate is Ra1 while a surface roughness Ra in a direction normal to the one direction of the ceramic substrate is Ra2, and a breakdown voltage of the ceramic substrate is 20 kV/mm or more. According to the above structure of the present invention, there can be provided a ceramic circuit board having an excellent heat-cycle resistance and bending strength characteristics without impairing a heat radiating property, and capable of increasing an operating reliability as electronic device.