CN-122007402-A - Silver paste and silver sintered body

Abstract

The invention provides a silver sintered body obtained from a silver paste with high bonding reliability during firing. Aspects of the present invention relate to a silver sintered body including silver particles and a silver compound, wherein the content of the silver compound is in a range of 0.31 wt% to 14 wt% with respect to the total weight of the silver sintered body.

Inventors

• TSUCHIYA TAKUMA
• MURAI JUNYA

Assignees

• 丰田自动车株式会社

Dates

Publication Date

20260512

Application Date

20251110

Priority Date

20241111

Claims (5)

1. 1. A silver sintered body comprising silver particles and a silver compound, characterized in that, The content of the silver compound is in the range of 0.31 wt% to 14 wt% with respect to the total weight of the silver sintered body.
2. 2. The silver sintered body according to claim 1, wherein, The silver compound is 1 or more selected from the group consisting of silver carbonate, silver oxide, silver formate, silver acetate and silver citrate.
3. 3. A silver sintered body according to claim 2, wherein, The average particle diameter of the silver compound is in the range of 1nm to 80 nm.
4. 4. A silver sintered body according to any one of claims 1 to 3, wherein the average particle diameter of the silver particles is in the range of 1nm to 1 μm.
5. 5. A silver paste comprising silver particles, a silver compound and a solvent, characterized in that, The silver compound is present in the form of solid particles, and the content of the silver compound is in the range of 0.25 wt% to 12 wt% inclusive with respect to the total weight of the silver paste, The average particle diameter of the silver compound is in the range of 1nm to 80 nm.

Description

Silver paste and silver sintered body Technical Field Aspects of the present invention relate to a silver paste and a silver sintered body. Background Metal nanoparticles having properties different from those of bulk materials are used or studied in various applications such as catalysts, ink materials, electronic parts and the like. Among them, silver nanoparticles have various excellent physicochemical properties on the functional surface, and various applications and manufacturing methods thereof have been studied and developed. For example, patent document 1 discloses a silver powder coated with a silver compound, which contains silver particles coated with a silver compound, the silver particles including silver particles as a core material and a coating portion of the silver compound coated on the surface of the silver particles. Patent document 2 discloses a conductive paste containing silver particles having an average particle diameter in the range of 1 to 500nm as the 1 st average particle diameter, 1 or more metals selected from the group consisting of aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, niobium, molybdenum, hafnium, tantalum, tungsten, indium, tin, gallium, germanium and bismuth, and an amine compound, wherein the mass of the amine compound is equal to or greater than the mass of the metals. Patent document 3 discloses a silver paste which contains silver particles (a) in a proportion of 80 to 92 mass% and an amine (C) in a proportion of less than 6 mass%, a silver compound (B), and a solvent (D). Patent document 4 discloses a silver paste comprising silver powder, a solvent and citric acid. Prior art literature Patent literature Patent document 1 Japanese patent laid-open publication No. 2005-298933 Patent document 2 International publication No. 2019/065965 Patent document 3 International publication No. 2023/190591 Patent document 4 Japanese patent application laid-open No. 2023-92937 Disclosure of Invention In recent years, in the field of electronic packaging, metal nanoparticles have been studied as a lead-free bonding material capable of bonding at low temperatures. While it is difficult to join a lead-free solder at a low temperature, a paste containing metal nanoparticles has a low melting point compared to a bulk material by utilizing the characteristics of metal nanoparticles, and on the other hand, when used for joining and sintering, has a characteristic of melting point as a bulk material, thereby enabling joining at a low temperature. However, in the case of producing a sintered body from a conventional slurry, a high firing temperature of 250 ℃ or higher is often required in order to improve the bonding strength. In addition, the slurry to which the organic component is added is often required, and conductivity may be deteriorated by limiting the organic component itself or a solvent applicable to the organic component. In addition, in the case of a silver sintered body, there are cases where the bonding strength is improved by the needle punching effect by mixing particles of an element different from silver in the silver paste, but the addition of the element different from silver may cause a decrease in sinterability, and a sufficient effect may not be obtained in bonding at 300 ℃. Further, since the conductivity of an element other than silver is lower than silver, there is a possibility that the conductivity of the silver sintered body is lowered. Accordingly, several embodiments of the present invention have an object to provide a silver sintered body obtained from a silver paste having high bonding reliability at the time of firing. As a result of various studies to achieve the above object, the present inventors have found that by adding a silver compound to a slurry composed of silver particles, a silver compound having low fluidity at high temperature acts as needle-punched particles of silver particles, and as a result, propagation of cracks in a silver sintered body can be suppressed, and high bonding reliability can be obtained, and completed several aspects of the present invention. That is, the gist of several aspects of the present invention is as follows. (1) A silver sintered body comprising silver particles and a silver compound, wherein the content of the silver compound is in the range of 0.31 wt% to 14 wt% inclusive with respect to the total weight of the silver sintered body. (2) The silver sintered body according to (1), wherein the silver compound is 1 or more compounds selected from the group consisting of silver carbonate, silver oxide, silver formate, silver acetate and silver citrate. (3) The silver sintered body according to (1) or (2), wherein the average particle diameter of the silver compound is in the range of 1nm to 80 nm. (4) The silver sintered body according to any one of (1) to (3), wherein an average particle diameter of the silver particles is in a range of 1nm or more and 1 μ