A layer arrangement for an electrostatic chuck comprises a first ceramic layer; a second ceramic layer; a metallised layered disposed between the first and second ceramic layers. The first ceramic layer comprises at least 90.0 wt % 5 alumina, titania, ZrO.sub.2, Y2O.sub.3, AlN, Si.sub.3N.sub.4, SiC, transition metal oxides or combinations thereof; and in the range of 0.1 to 10.0 wt % tantalum oxide (Ta.sub.2O.sub.5).

A gas plug of the present disclosure is composed of a columnar porous composite in which a plurality of silicon compound phases containing silicon carbide as a main component are connected to each other via a silicon phase having silicon as a main component. The porous composite is housed inside a tubular body made from a dense ceramic.

A heat sink-attached power module substrate board has a ratio (A1×t1×σ1×α1)/{(A2×t2×σ2×α2)+(A3×t3×σ3×α3)} at 25° C. is not less than 0.70 and not more than 1.30, where A1 (mm.sup.2) is a bonding area of a second layer and a first layer composing a circuit layer; t1 (mm) is an equivalent board thickness, σ1 (N/mm.sup.2) is yield strength, and α1 (/K) is a linear expansion coefficient, all of the second layer, where A2 (mm.sup.2) is a bonding area of the heat radiation-side bonding material and the metal layer; t2 (mm) is equivalent board thickness, σ2 (N/mm.sup.2) is yield strength, and α2 (/K) is a linear expansion coefficient, all of the heat radiation-side bonding material, and where A3 (mm.sup.2) is a bonding area of the heat sink and the heat radiation-side bonding material; t3 (mm) is equivalent board thickness, σ3 (N/mm.sup.2) is yield strength, and α3 (/K) is a linear expansion coefficient, all of the heat sink.

What is provided is a method of manufacturing an insulating circuit board with a heatsink including an insulating circuit board and a heatsink, the heatsink being bonded to the metal layer side of the insulating circuit board, the metal layer being formed of aluminum, and a bonding surface of the heatsink with the insulating circuit board being formed of an aluminum alloy having a solidus temperature of 650° C. or lower. This method includes a high alloy element concentration portion forming step (S02) of forming a high alloy element concentration portion and a heatsink bonding step (S03) of bonding the heatsink, in which a ratio tb/ta of a thickness tb of the brazing material layer to a thickness to of the core material in the clad material is in a range of 0.1 to 0.3.

A method to form a machinable ceramic matrix composite comprises forming a porous ceramic multilayer on a surface of a fiber preform. In one example, the porous ceramic multilayer comprises a gradient in porosity in a direction normal to the surface. In another example, the porous ceramic multilayer includes low-wettability particles having a high contact angle with molten silicon, where an amount of the low-wettability particles in the porous ceramic multilayer varies in a direction normal to the surface. After forming the porous ceramic multilayer, the fiber preform is infiltrated with a melt, and the melt is cooled to form a ceramic matrix composite with a surface coating thereon. An outer portion of the surface coating is more readily machinable than an inner portion of the surface coating. The outer portion of the surface coating is machined to form a ceramic matrix composite having a machined surface with a predetermined surface finish and/or dimensional tolerance.

A scribe line is formed on a first surface of a nitride ceramic base material by a laser. Next, the nitride ceramic base material is divided along the scribe line. The scribe line includes a plurality of recessed portions. The plurality of recessed portions are formed in a row on the first surface of the nitride ceramic base material. A depth of each of the plurality of recessed portions is equal to or greater than 0.70 times and equal to or smaller than 1.10 times an opening width of each of the plurality of recessed portions. The opening width of each of the plurality of recessed portions is equal to or greater than 1.00 times and equal to or smaller than 1.10 times an inter-center distance of the plurality of recessed portions.

A soldering material (1) for active soldering, in particular for active soldering of a metallization (3) to a carrier layer (2) comprising ceramics, wherein the soldering material comprises copper and is substantially silver-free.

A joint body of the present disclosure includes a substrate including a base member having insulating properties and a metal layer positioned on a first main surface of the base member, a metal joint layer, and a metal member. The metal joint layer is positioned between the metal layer and the metal member of the substrate. The metal joint layer includes a nickel layer, a solder layer, and a composite layer containing a mix of nickel and solder. The nickel layer, the composite layer, and the solder layer are positioned in this order from the metal layer side to the metal member side. The nickel in the composite layer extends from the nickel layer in the thickness direction and forms protrusions and recesses.

A method for preparing a ceramic copper clad laminate is provided, including following steps: providing a copper material; forming a copper oxide layer on a surface of the copper material; thermally treating the copper material on which the copper oxide layer is formed, to diffuse oxygen atoms in the copper material; removing the copper oxide layer on the thermally treated copper material; and soldering the copper-oxide-layer-removed copper material to a ceramic substrate to obtain a ceramic copper clad laminate.

An insulating substrate in which one principal surface of a heat-dissipation-side metal plate is brazed to one principal surface of a ceramic substrate via a brazing material layer provided therebetween, in which a Ni plating layer that covers the brazing material layer exposed between the ceramic substrate and the heat-dissipation-side metal plate is provided, and at least a portion of the other principal surface of the heat-dissipation-side metal plate is not covered with a Ni plating layer, leaving the surface of the heat-dissipation-side metal plate exposed. According to the present invention, it becomes possible to obtain the insulating substrate having excellent furnace passing resistance of the insulating substrate (alone) and further having excellent heat cycle characteristics in a state of a heat sink plate being soldered to the insulating substrate.