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KR-20260066757-A - Spherical silver powder, and method for manufacturing spherical silver powder

KR20260066757AKR 20260066757 AKR20260066757 AKR 20260066757AKR-20260066757-A

Abstract

The objective of the present invention is to provide spherical silver powder capable of imparting excellent fine line printability to a conductive paste. The present invention is a spherical silver powder having a surface treatment agent present, wherein, in a measurement of the coefficient of thermal expansion, the maximum value of the coefficient of thermal expansion based on the value at 50°C is 0.3% or less, the BET specific surface area is 0.1 m²/g or more and 0.8 m²/g or less, and the D 90 value is 2.0 µm or more and 4.0 µm or less.

Inventors

  • 나카노야 타로
  • 고토 키미카

Assignees

  • 도와 일렉트로닉스 가부시키가이샤

Dates

Publication Date
20260512
Application Date
20241017
Priority Date
20231110

Claims (8)

  1. A surface treatment agent is present, and In the measurement of the coefficient of thermal expansion, the maximum value of the coefficient of thermal expansion based on the value at 50℃ is 0.3% or less, and The BET specific surface area is 0.1 m²/g or more and 0.8 m²/g or less, and Spherical silver powder with a D 90 value of 2.0㎛ or more and 4.0㎛ or less.
  2. In paragraph 1, Spherical silver powder with a D 50 value of 1.0㎛ or more and 2.5㎛ or less.
  3. In paragraph 1, Spherical silver powder with a D 10 value of 0.5㎛ or more and 1.2㎛ or less.
  4. In any one of paragraphs 1 through 3, The above surface treatment agent is a spherical silver powder, which is one or more surface treatment agents selected from the group consisting of fatty acids, compounds having an azole structure, and fatty acid salts.
  5. A method for producing spherical silver powder by adding a reducing agent to an aqueous reaction system containing a chelating agent composed of silver ions and a polymer to reduce and precipitate silver particles, wherein A carbonate concentration adjustment process for adjusting the ratio of the total molar concentration of carbonate to the total molar concentration of silver in the aqueous reaction system to 0.004 or more and 0.051 or less before adding the reducing agent to the aqueous reaction system, and A method for manufacturing spherical silver powder, comprising a surface treatment agent addition process of adding a surface treatment agent to the aqueous reaction system after the silver particles are precipitated.
  6. In paragraph 5, A method for manufacturing spherical silver powder, wherein the above-mentioned surface treatment agent is one or more surface treatment agents selected from the group consisting of fatty acids, compounds having an azole structure, and fatty acid salts.
  7. In paragraph 5, A method for manufacturing spherical silver powder, wherein the chelating agent is polyethyleneimine with a weight average molecular weight of 600 or less.
  8. In any one of paragraphs 5 through 7, The above reducing agent is hydrazine, a method for manufacturing spherical silver powder.

Description

Spherical silver powder, and method for manufacturing spherical silver powder The present invention relates to spherical silver powder and a method for manufacturing spherical silver powder. A method of forming conductive films, such as electrodes or electrical wiring, by applying or printing a conductive paste containing conductive metal powder onto a substrate, such as a film, substrate, or electronic component, and then heating to dry and cure or sintering, has been widely used for a long time. However, with the recent increase in the performance of electronic devices, conductive films formed using conductive paste are required to have lower resistance, and this requirement is becoming stricter year by year. In response to the above requirements, for example, Patent Document 1 proposes a silver powder having a predetermined surface treatment agent, a predetermined thermal expansion coefficient, a BET value (specific surface area), and a difference in ignition loss, with the aim of suppressing blistering of the conductive film during firing of the sintered conductive paste and lowering the electrical resistance value of the cured film (conductive film). Figure 1 is a graph showing the thermomechanical analysis results of the spherical silver powder obtained in Example 1. Figure 2 is an enlarged graph of a portion of the graph in Figure 1. Figure 3 is a graph showing the thermomechanical analysis results of the spherical silver powder obtained in Example 2. Figure 4 is an enlarged graph of a portion of the graph in Figure 3. Figure 5 is a graph showing the thermomechanical analysis results of the spherical silver powder obtained in Example 3. Figure 6 is an enlarged graph of a portion of the graph in Figure 5. Figure 7 is a graph showing the thermomechanical analysis results of the spherical silver powder obtained in Example 4. Figure 8 is an enlarged graph of a portion of the graph in Figure 7. Figure 9 is a graph showing the thermomechanical analysis results of the spherical silver powder obtained in Example 5. Figure 10 is an enlarged graph of a portion of the graph in Figure 9. Figure 11 is a graph showing the thermomechanical analysis results of the spherical silver powder obtained in Example 6. Figure 12 is an enlarged graph of a portion of the graph in Figure 11. Figure 13 is a graph showing the thermomechanical analysis results of the spherical silver powder obtained in Example 7. Figure 14 is an enlarged graph of a portion of the graph in Figure 13. Figure 15 is a graph showing the thermomechanical analysis results of the spherical silver powder obtained in Comparative Example 1. Figure 16 is an enlarged graph of a portion of the graph in Figure 15. Figure 17 is a graph showing the thermomechanical analysis results of the spherical silver powder obtained in Comparative Example 2. Figure 18 is an enlarged graph of a portion of the graph in Figure 17. Figure 19 is a graph showing the thermomechanical analysis results of the spherical silver powder obtained in Comparative Example 3. Figure 20 is an enlarged graph of a portion of the graph in Figure 19. Figure 21 is a graph showing the thermomechanical analysis results of the spherical silver powder obtained in Comparative Example 4. Figure 22 is an enlarged graph of a portion of the graph in Figure 21. Figure 23 is an SEM image of spherical silver powder obtained in Example 1 at 10,000x magnification. Figure 24 is an SEM image of spherical silver powder obtained in Example 2 at 10,000x magnification. Figure 25 is an SEM image of spherical silver powder obtained in Example 3 at 10,000x magnification. Figure 26 is an SEM image of spherical silver powder obtained in Example 4 at 10,000x magnification. Figure 27 is an SEM image of spherical silver powder obtained in Example 5 at 10,000x magnification. Figure 28 is an SEM image of spherical silver powder obtained in Example 6 at 10,000x magnification. Figure 29 is an SEM image of spherical silver powder obtained in Example 7 at 10,000x magnification. Figure 30 is an SEM image of spherical silver powder obtained in Comparative Example 3 at 10,000x magnification. The spherical silver powder of the present invention is suitable for use as a conductive filler for conductive paste. The conductive paste using the spherical silver powder of the present invention can be used to form a conductive pattern or an electrode on a substrate. The conductive paste using the spherical silver powder of the present invention can form a conductive film, such as a conductive pattern or an electrode, by printing it on a substrate, for example, by screen printing, offset printing, photolithography, etc. (Terminology and Measurement Methods) First, prior to the description of the embodiments, terms and measurement methods in this specification will be explained. <Confirmation of Spherical Silver Powder (Particle Shape)> In this specification, spherical silver powder refers to silver powder in which the average shape factor of 400