Bonded substrate, and method for manufacturing bonded substrate
AssigneeNGK Insulators, Ltd.
InventorTakashi Ebigase
Life of this patent
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Abstract
A bonded substrate includes: a silicon nitride ceramic substrate; a copper plate; and a bonding layer bonding the copper plate to the silicon nitride ceramic substrate, wherein the bonding layer has a first interface in contact with the silicon nitride ceramic substrate and a second interface in contact with the copper plate, and contains a nitride and a silicide of an active metal as at least one metal selected from the group consisting of titanium and zirconium, an atomic fraction of nitrogen of the bonding layer is greatest at the first interface and is smallest at the second interface, and a sum of atomic fractions of the active metal and silicon of the bonding layer is smallest at the first interface and is greatest at the second interface.
Claims20
A bonded substrate comprising:
- a silicon nitride ceramic substrate;
- a copper plate;
- and
- a bonding layer bonding the copper plate to the silicon nitride ceramic substrate, wherein
- the bonding layer
- has a first interface in contact with the silicon nitride ceramic substrate and a second interface in contact with the copper plate, and
- contains a nitride and a silicide of an active metal as at least one metal selected from the group consisting of titanium and zirconium,
- an atomic fraction of nitrogen of the bonding layer is greatest at the first interface and is smallest at the second interface, and
- a sum of atomic fractions of the active metal and silicon of the bonding layer is smallest at the first interface and is greatest at the second interface.
A method for manufacturing a bonded substrate of a silicon nitride ceramic substrate and a copper plate, the method comprising:
- a brazing material layer forming step of forming a brazing material layer on the silicon nitride ceramic substrate, the brazing material layer being formed of a brazing material containing a silver powder and a powder of a hydride of an active metal as at least one metal selected from the group consisting of titanium and zirconium;
- an intermediate product forming step of disposing the copper plate on the brazing material layer to obtain an intermediate product including the silicon nitride ceramic substrate, the copper plate, and the brazing material layer;
- and
- a bonding layer forming step of heating the intermediate product under pressure to diffuse silver contained in the brazing material layer into the copper plate and supply nitrogen and silicon contained in the silicon nitride ceramic substrate to the brazing material layer to thereby change the brazing material layer into a bonding layer bonding the copper plate to the silicon nitride ceramic substrate, wherein
- in the brazing material layer forming step, a silver powder having D50 of 0.5 μm to 1.5 μm and D95 of 2.0 μm to 3.5 μm in particle size distribution is used as the silver powder contained in the brazing material, and
- in the bonding layer forming step, the bonding layer is formed so as to
- have a first interface in contact with the silicon nitride ceramic substrate and a second interface in contact with the copper plate, and
- contain a nitride and a silicide of an active metal as at least one metal selected from the group consisting of titanium and zirconium,
- an atomic fraction of nitrogen of the bonding layer becomes greatest at the first interface and becomes smallest at the second interface, and
- a sum of atomic fractions of the active metal and silicon of the bonding layer becomes smallest at the first interface and becomes greatest at the second interface.
Dependencies are inferred from the claim text.