Bonded assembly, and ceramic circuit substrate and semiconductor device using the same
A bonded assembly according to the present embodiment, includes a metal plate and a ceramic substrate bonded to each other through a bonding layer containing Ag. In the bonded assembly, in a measurement region that is formed in a cross section formed by a thickness direction of the bonding layer and an orthogonal direction thereto, and that has a size of a length in the thickness direction of the bonding layer×a length of 200 μm in the orthogonal direction, a Ag-rich region having a Ag concentration of 60 at % or more has an area ratio of 70% or less to a Ag-poor region having a Ag concentration of 50 at % or less.
1. A bonded assembly, comprising a metal plate and a ceramic substrate bonded to each other through a bonding layer containing Ag, wherein
the bonding layer contains Sn or In, and a concentration of Sn or In in a measurement region is in a range of 1 at % or more and 6 at % or less,
the measurement region that is formed in a cross section formed by a thickness direction of the bonding layer and an orthogonal direction thereto, and that has a size of a length in the thickness direction of the bonding layer×a length of 200 μm in the orthogonal direction, comprises a Ag-rich region having a Ag concentration of 60 at % or more that has an area of 70% or less of the area of the measurement region, and Ag-poor regions each having a Ag concentration of 50 at % or less, and
at least one region where the Ag-poor regions are linked to each other in the thickness direction of the bonding layer is present in a triple continuous measurement region where three measurement regions are continuously linked to each other in the orthogonal region.
2. The bonded assembly according to claim 1 , wherein the length in the thickness direction of the bonding layer is in a range of 10 μm or more and 60 μm or less.
3. The bonded assembly according to claim 1 , wherein the ceramic substrate is a silicon nitride substrate, and the metal plate is a copper plate.
4. The bonded assembly according to claim 1 , wherein the ceramic substrate is a silicon nitride substrate having a thickness of 0.4 mm or less, and the metal plate is a copper plate having a thickness of 0.5 mm or more.
5. A ceramic circuit substrate, comprising the bonded assembly according to claim 1 .
6. A semiconductor device, comprising a semiconductor element mounted on the ceramic circuit substrate according to claim 5 .
7. The bonded assembly according to claim 2 , wherein the ceramic substrate is a silicon nitride substrate, and the metal plate is a copper plate.
8. The bonded assembly according to claim 7 , wherein the ceramic substrate is a silicon nitride substrate having a thickness of 0.4 mm or less, and the metal plate is a copper plate having a thickness of 0.5 mm or more.
9. A ceramic circuit substrate, comprising the bonded assembly according to claim 8 .
10. A semiconductor device, comprising a semiconductor element mounted on the ceramic circuit substrate according to claim 9 .