US-12622269-B2 - Copper/ceramic bonded body and insulating circuit substrate

Abstract

The copper/ceramic bonded body according to the present invention is a copper/ceramic bonded body obtained by bonding copper members consisting of copper or a copper alloy to a ceramic member, where in an edge region E of each of the copper members, an area ratio of each of Ag solid solution parts having an Ag concentration of 0.5% by mass or more and 15% by mass or less is set in a range of 0.03 or more and 0.35 or less.

Inventors

• Nobuyuki Terasaki

Assignees

• MITSUBISHI MATERIALS CORPORATION

Dates

Publication Date

20260505

Application Date

20220729

Priority Date

20210730

Claims (6)

1. 1 . A copper/ceramic bonded body obtained by bonding a copper member consisting of copper or a copper alloy to a ceramic member, wherein in an edge region of the copper member, an area ratio of an Ag solid solution part having an Ag concentration of 0.5% by mass or more and 15% by mass or less is set in a range of 0.03 or more and 0.35 or less.
2. 2 . The copper/ceramic bonded body according to claim 1 , wherein at a bonded interface between the ceramic member and the copper member, an active metal compound layer is formed on a side of the ceramic member, and a thickness t1 of the active metal compound layer is set in a range of 0.05 μm or more and 0.8 μm or less.
3. 3 . The copper/ceramic bonded body according to claim 1 , wherein at a bonded interface between the ceramic member and the copper member, an Ag—Cu alloy layer is formed on a side of the copper member, and a thickness t2 of the Ag—Cu alloy layer is set in a range of 1 μm or more and 15 μm or less.
4. 4 . An insulating circuit substrate obtained by bonding a copper sheet consisting of copper or a copper alloy to a surface of a ceramic substrate, wherein in an edge region of the copper sheet, an area ratio of an Ag solid solution part having an Ag concentration of 0.5% by mass or more and 15% by mass or less is set in a range of 0.03 or more and 0.35 or less.
5. 5 . The insulating circuit substrate according to claim 4 , wherein at a bonded interface between the ceramic substrate and the copper sheet, an active metal compound layer is formed on a side of the ceramic substrate, and a thickness t1 of the active metal compound layer is set in a range of 0.05 μm or more and 0.8 μm or less.
6. 6 . The insulating circuit substrate according to claim 4 , wherein at a bonded interface between the ceramic substrate and the copper sheet, an Ag—Cu alloy layer is formed on a side of the copper sheet, and a thickness t2 of the Ag—Cu alloy layer is set in a range of 1 μm or more and 15 μm or less.

Description

TECHNICAL FIELD The present invention relates to a copper/ceramic bonded body obtained by bonding a copper member consisting of copper or a copper alloy to a ceramic member, and an insulating circuit substrate including a ceramic substrate and a copper sheet consisting of copper or a copper alloy, which is bonded to a surface of the ceramic substrate. Priority is claimed on Japanese Patent Application No. 2021-125532, filed Jul. 30, 2021, the content of which is incorporated herein by reference. BACKGROUND ART A power module, an LED module, and a thermoelectric module have a structure in which a power semiconductor element, an LED element, and a thermoelectric element are bonded to an insulating circuit substrate in which a circuit layer consisting of a conductive material is formed on one surface of an insulating layer. For example, a power semiconductor element for high power control, which is used for controlling wind power generation, an electric vehicle, a hybrid vehicle, or the like, generates a large amount of heat during operation, and thus, an insulating circuit substrate including a ceramic substrate, a circuit layer formed by bonding a metal plate having excellent electrical conductivity to one surface of the ceramic substrate, and a metal layer for heat radiation, which is formed by bonding a metal plate to the other surface of the ceramic substrate has been widely used in the related art as a substrate on which the power semiconductor element is mounted. For example, Patent Document 1 proposes an insulating circuit substrate in which a circuit layer and a metal layer are formed by bonding a copper sheet to one surface and the other surface of a ceramic substrate. In Patent Document 1, the copper sheet is disposed on one surface of the ceramic substrate and the other surface thereof with an Ag—Cu—Ti-based brazing material being interposed, and then a heating treatment is carried out to bond the copper sheet (so-called active metal brazing method). In addition, Patent Document 2 proposes a power module substrate in which a copper sheet consisting of copper or a copper alloy is bonded to a ceramic substrate consisting of AlN or Al2O3 by using a bonding material containing Ag and Ti. Further, Patent Document 3 proposes a power module substrate in which an aluminum sheet consisting of aluminum or an aluminum alloy is bonded to a ceramic substrate by using a brazing material consisting of an alloy such as an Al—Si-based, Al—Ge-based, Al—Cu-based, Al—Mg-based, or Al—Mn-based alloy. In addition, according to Patent Document 3, an overhang part is formed in the periphery of each of a circuit layer formed on one surface of the ceramic substrate and a heat radiation layer formed on the other surface of the ceramic substrate. As a result, insulating properties between the circuit layer and the heat radiation layer are ensured, and concurrently, the heat capacity in the circuit layer and the heat radiation layer is increased. CITATION LIST Patent Documents [Patent Document 1] Japanese Patent No. 3211856 [Patent Document 2] Japanese Patent No. 5757359 [Patent Document 3] Japanese Patent No. 5957862 SUMMARY OF INVENTION Technical Problem By the way, in recent years, there is a tendency that a heat generation temperature of a semiconductor element mounted on an insulating circuit substrate increases, and an insulating circuit substrate is required to have a thermal cycle reliability that can withstand a thermal cycle more severe than a thermal cycle in the related art. Here, in an insulating circuit substrate obtained by bonding a copper sheet to a ceramic substrate, in a case where an overhang part is formed on the circuit layer as described in Patent Document 3, there is a risk that thermal stress is concentrated on the edge of the circuit layer, and the bonding reliability is decreased in a case where a thermal cycle is loaded. In addition, in the edge of the copper member, Ag contained in the bonding material undergoes solid solution to be subject to solid solution and hardening. In a case where the edge of the copper member is hardened by the solid solution hardening, there is also a risk that thermal stress is concentrated on the edge of the circuit layer, and the bonding reliability is decreased. The present invention has been made in consideration of the above-described circumstances, and an objective of the present invention is to provide a copper/ceramic bonded body having an excellent thermal cycle reliability, which can suppress the occurrence of breaking in a ceramic member even in a case where a severe thermal cycle is loaded, and an insulating circuit substrate consisting of the copper/ceramic bonded body. Solution to Problem In order to solve the above-described problem, the copper/ceramic bonded body according to one aspect of the present invention is characterized by being a copper/ceramic bonded body obtained by bonding a copper member consisting of copper or a copper alloy to a ceramic me