A method of making a heater includes an aluminum nitride base having equal to or less than 1% impurities, particularly one embodiment having none of polybrominated biphenyl, polybrominated diphenyl ether, hexabromocyclododecane, polyvinyl chloride, chlorinated paraffin, phthalate, cadmium, hexavalent chromium, lead, and mercury. The base is fired in a heating unit before any layering. Thereafter, on a topside and backside of the base a conductor layer is layered and allowed to settle and dry before firing. Next, a resistive layer is layered on the base from a resistor paste such that the resistive layer connects to the conductor layer on the topside. The resistor paste is allowed to settle and dry and then the base with the conductor and resistor layers is fired. At least four layers of glass are layered next over the resistive layer, each instance thereof including layering a glass, drying the glass and firing.

The present invention focuses on a silicon nitride substrate having high mechanical strength, high thermal conductivity and the like, and takes advantage of such properties to provide: a ceramic substrate capable of providing improvement in a bonding property between a silicon nitride substrate and a ceramic layer which uses a dielectric ceramic material capable of being simultaneously sintered with a low-resistance conductive material such as a low-melting metal (Ag or Cu); and a method for producing the ceramic substrate. The ceramic substrate of the present invention is obtained by stacking and bonding a silicon nitride substrate and a ceramic layer composed of a dielectric ceramic material, wherein: the dielectric ceramic material contains Mg, Al, and Si as main ingredients, and Bi or B as an accessory ingredient; and the ceramic layer includes a region with a high Si element concentration at a bonding interface with the silicon nitride substrate.

The present disclosure relates to a multilayer ceramic substrate preparation method. The multilayer ceramic substrate preparation method according to the present disclosure includes firing a plurality of ceramic green sheets, to create a plurality of ceramic thin films; forming a via hall in each of the plurality of ceramic thin films; filling the via hall of the plurality of ceramic thin films with conductive paste, and heat treating the via hall filled with the conductive paste, to form a via electrode; printing a pattern on a cross section of each of the plurality of ceramic thin films, and heat treating the printed pattern, to form an inner electrode; applying a bonding agent on the cross section of each of the ceramic thin films excluding an uppermost ceramic thin film of the plurality of ceramic thin films; aligning and laminating each of the plurality of ceramic thin films such that each of the plurality of ceramic thin films is electrically connected through the via electrode and the inner electrode; and firing or heat treating the laminated plurality of ceramic thin films.

According to one embodiment, when a DSC curve is measured using a differential scanning calorimeter (DSC) for a brazing material for bonding a ceramic substrate and a metal plate, the brazing material has an endothermic peak within a range of not less than 550° C. and not more than 700° C. in a heating process. The brazing material favorably includes Ag, Cu, and Ti. The brazing material favorably has not less than two of the endothermic peaks within a range of not less than 550° C. and not more than 650° C. in the heating process.

A ceramic copper circuit board according to an embodiment includes a ceramic substrate and a first copper part. The first copper part is bonded at a first surface of the ceramic substrate via a first brazing material part. The thickness of the first copper part is 0.6 mm or more. The side surface of the first copper part includes a first sloped portion. The width of the first sloped portion is not more than 0.5 times the thickness of the first copper part. The first brazing material part includes a first jutting portion jutting from the end portion of the first sloped portion. The length of the first jutting portion is not less than 0 μm and not more than 200 μm. The contact angle between the first jutting portion and the first sloped portion is 65° or less.

A ceramic copper circuit board according to an embodiment includes a ceramic substrate and a first copper part. The first copper part is bonded at a first surface of the ceramic substrate via a first brazing material part. The thickness of the first copper part is 0.6 mm or more. The side surface of the first copper part includes a first sloped portion. The width of the first sloped portion is not more than 0.5 times the thickness of the first copper part. The first brazing material part includes a first jutting portion jutting from the end portion of the first sloped portion. The length of the first jutting portion is not less than 0 μm and not more than 200 μm. The contact angle between the first jutting portion and the first sloped portion is 65° or less.

A ceramic copper circuit board according to an embodiment includes a ceramic substrate and a first copper part. The first copper part is bonded at a first surface of the ceramic substrate via a first brazing material part. The thickness of the first copper part is 0.6 mm or more. The side surface of the first copper part includes a first sloped portion. The width of the first sloped portion is not more than 0.5 times the thickness of the first copper part. The first brazing material part includes a first jutting portion jutting from the end portion of the first sloped portion. The length of the first jutting portion is not less than 0 μm and not more than 200 μm. The contact angle between the first jutting portion and the first sloped portion is 65° or less.

A conductive pattern having high dispersion stability and a low resistance over a board is formed. A dispersing element (1) contains a copper oxide (2), a dispersing agent (3), and a reductant. Content of the reductant is in a range of a following formula (1). Content of the dispersing agent is in a range of a following formula (2).
0.0001≤(reductant mass/copper oxide mass)≤0.10  (1)
0.0050≤(dispersing agent mass/copper oxide mass)≤0.30  (2)
The dispersing element containing the reductant promotes reduction of copper oxide to copper in firing and promotes sintering of the copper.

The purpose of the present invention is to provide an electronic component in which a copper electrode and an inorganic substrate exhibit strong adhesion to each other. A method for producing an electronic component according to the present invention comprises: an application step wherein a paste is applied onto an inorganic substrate, which paste contains copper particles, copper oxide particles and/or nickel oxide particles, and inorganic oxide particles having a softening point: a sintering step wherein a sintered body which contains at least copper is formed by means of heating in an inert gas atmosphere at a temperature that is less than the softening point of the inorganic oxide particles but not less than the sintering temperature of the copper particles; and a softening step wherein hearing is carried out in an inert gas atmosphere at a temperature that is not less than the softening point of the inorganic oxide particles.

The glass ceramic material of the present disclosure contains a glass that contains SiO.sub.2, B.sub.2O.sub.3, Al.sub.2O.sub.3, and M.sub.2O, where M is an alkali metal, and a filler that contains quartz, Al.sub.2O.sub.3, and ZrO.sub.2. The glass ceramic material contains the glass in an amount of 57.4% by weight or more and 67.4% by weight or less, the quartz in the filler in an amount of 29% by weight or more and 39% by weight or less, the Al.sub.2O.sub.3 in the filler in an amount of 1.8% by weight or more and 5% by weight or less, and the ZrO.sub.2 in the filler in an amount of 0.3% by weight or more and 1.8% by weight or less.