In a silicon nitride substrate including a silicon nitride sintered body including silicon nitride crystal grains and a grain boundary phase, a plate thickness of the silicon nitride substrate is 0.4 mm or les, and a percentage of a number of the silicon nitride crystal grains including dislocation defect portions inside the silicon nitride crystal grains in a 50 μm×50 μm observation region of any cross section or surface of the silicon nitride sintered body is not less than 0% and not more than 20%. Etching resistance can be increased when forming the circuit board.

A method for manufacturing a metal-ceramic substrate (1) includes providing a ceramic layer (10), a metal layer (20) and a solder layer (30) coating the ceramic layer (10) and/or the metal layer (20) and/or the solder layer (30) with an active metal layer (40), arranging the solder layer (30) between the ceramic layer (10) and the metal layer (20) along a stacking direction (S), forming a solder system (35) comprising the solder layer and the active metal layer (40), wherein a solder material of the solder layer (30) is free of a melting point lowering material and bonding the metal layer (20) to the ceramic layer (10) via the solder system (35) by means of an active solder process.

A copper-ceramic composite: includes a ceramic substrate containing alumina and a copper or copper alloy coating on the ceramic substrate. The alumina has a mean grain shape factor R.sub.a(Al.sub.2O.sub.3), defined as the arithmetic mean of the shape factors R of the alumina grains, of at least 0.4.

A ceramic composite can include a first ceramic phase and a second ceramic phase. The first ceramic phase can include a silicon carbide. The second phase can include a boron carbide. In an embodiment, the silicon carbide in the first ceramic phase can have a grain size in a range of 0.8 to 200 microns. The first phase, the second phase, or both can further include a carbon. In another embodiment, at least one of the first ceramic phase and the second ceramic phase can have a median minimum width of at least 5 microns.

A copper/ceramic bonded body includes: a copper member (12) made of copper or a copper alloy; and a ceramic member (11) made of nitrogen-containing ceramics, the copper member (12) and the ceramic member (11) being bonded to each other, in which a Mg solid solution layer in which Mg is solid-soluted in a Cu matrix is formed at a bonding interface between the copper member (12) and the ceramic member (11), an active metal nitride layer (41) containing a nitride of one or more active metals selected from Ti, Zr, Nb, and Hf is formed on a ceramic member (11) side, and a thickness of the active metal nitride layer (41) is set to be in a range of 0.05 μm or more and 1.2 μm or less.

A method for producing a metal-ceramic substrate with a plurality of electrically conductive vias includes: attaching a first metal layer in a planar manner to a first surface side of a ceramic layer; after attaching the first metal layer, introducing a copper hydroxide or copper acetate brine into a plurality of holes in the ceramic layer delimiting a via, to form an assembly; converting the copper hydroxide or copper acetate brine into copper oxide; subjecting the assembly to a high-temperature step above 500° C. in which the copper oxide forms a copper body in the plurality of holes; and after converting the copper hydroxide or copper acetate brine into the copper oxide, attaching a second metal layer in a planar manner to a second surface side of the ceramic layer opposite the first surface side. The copper body produces an electrically conductive connection between the first and the second metal layers.

A solder material (30) for bonding a metal layer (20) to a ceramic layer (10), in particular for forming a metal-ceramic substrate as a carrier for electrical components, comprising: a base material and an active metal, wherein the solder material (30) is a foil comprising the base material in a first layer (31) and the active metal in a second layer (32), and wherein the foil has a total thickness (GD) which is less than 50 μm, preferably less than 25 μm and particularly preferably less than 15 μm.

A copper-ceramic bonded body includes a copper member made of copper or a copper alloy, and a ceramic member made of silicon nitride, the copper member and the ceramic member being bonded to each other, in which a maximum length of a Mg—N compound phase which is present at a bonded interface between the copper member and the ceramic member is less than 100 nm, and in a unit length along the bonded interface, the number density of the Mg—N compound phase in a range of a length of 10 nm or more and less than 100 nm is less than 8 pieces/μm.

Methods of forming joinery between components formed from dissimilar materials, and assemblies utilizing the joinery. The components include interface surfaces having complementary peaks and valleys that interlock. A compliant interface is formed between the interface surfaces and the interface can be configured to provide functionality.

The electrostatic chuck includes an insulating substrate having a placement surface on which a suction target object is placed and an opposite surface provided on an opposite side to the placement surface; and a gas hole penetrating from the opposite surface to the placement surface. The gas hole has a first hole portion extending from the opposite surface toward the placement surface, a second hole portion extending from the placement surface toward the opposite surface, and a third hole portion provided between the first hole portion and the second hole portion and formed to communicate the first hole portion and the second hole portion each other. The first hole portion is provided not to overlap with the second hole portion in a plan view.