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KR-20260066118-A - Copper powder and conductive paste

KR20260066118AKR 20260066118 AKR20260066118 AKR 20260066118AKR-20260066118-A

Abstract

Copper powder having D BET / D 50 , obtained from the particle diameter D 50 at 50% cumulative frequency in a volume-based cumulative frequency distribution curve measured using a laser diffraction scattering particle size distribution measuring device and the particle diameter D BET calculated from the specific surface area s by the nitrogen adsorption method, being 0.70 or more and 1.20 or less, and the coefficient of variation (SD / MV) obtained from the volume average diameter MV and standard deviation SD of the particle size distribution measured by the laser diffraction scattering particle size distribution measuring method being 0.50 or less.

Inventors

  • 다키구치 사토시

Assignees

  • 후루카와 케미컬즈 가부시키가이샤

Dates

Publication Date
20260512
Application Date
20240911
Priority Date
20230928

Claims (7)

  1. D BET / D 50 , obtained from the particle size D 50 at a cumulative frequency of 50% in the volume-based cumulative frequency distribution curve measured using a laser diffraction scattering particle size distribution measuring device and the particle size D BET calculated from the specific surface area s by the nitrogen adsorption method, is 0.70 or greater and 1.20 or less, and Copper powder having a coefficient of variation (SD/MV) of 0.50 or less, obtained from the volume average diameter MV and standard deviation SD of the particle size distribution measured by the laser diffraction scattering particle size distribution method.
  2. In paragraph 1, Copper powder having a D 50 of 5.0 μm or less.
  3. In paragraph 1 or 2, Copper powder having a D BET of 0.1 μm or more and 5.0 μm or less.
  4. In any one of paragraphs 1 through 3, Copper powder with a residual chlorine content of 50 ppm or less, quantified by chemical analysis.
  5. In any one of paragraphs 1 through 4, Copper powder obtained by a disproportionation reaction.
  6. In any one of paragraphs 1 through 5, Copper powder containing a fatty acid film on the surface.
  7. A conductive paste comprising copper powder, resin, and solvent as described in any one of claims 1 to 6.

Description

Copper powder and conductive paste The present invention relates to copper powder and conductive paste. Conventionally, copper powder has been used as a raw material for conductive pastes used in forming wiring on printed circuit boards. However, with the recent miniaturization of printed circuit boards and the resulting finer wiring, there is a demand for copper powder for conductive pastes capable of handling such fine wiring. Patent Document 1 discloses a copper powder composed of copper particles coated with collagen peptides, wherein the average particle size D SEM , determined by the circular equivalent diameter of primary particles obtained from an SEM image, is 0.1 to 1.0 μm, and the carbon content in the powder is 0.10 to 0.50 mass%. In addition, Patent Document 1 states that according to the invention described in Patent Document 1, it is possible to provide a copper powder of a relatively fine size in which the average particle size of the primary particles is 1 μm or less, at a high temperature at which sintering occurs. The present invention is described below based on embodiments. In addition, if numerical ranges are listed in steps, the upper and lower limits of each numerical range can be combined arbitrarily. (1) Copper powder The copper powder of the present embodiment is described below. The copper powder of the present embodiment has a particle size D 50 when the cumulative frequency is 50% in the volume-based cumulative frequency distribution curve measured using a laser diffraction scattering particle size distribution measuring device, and a particle size D BET / D 50 obtained from the specific surface area s calculated by the nitrogen adsorption method , which is 0.70 or higher and 1.20 or lower, and a coefficient of variation (SD / MV) obtained from the volume average diameter MV and standard deviation SD of the particle size distribution measured by the laser diffraction scattering particle size distribution measuring method is 0.50 or lower. Although the mechanism by which the aforementioned problem is solved by the copper powder of the present embodiment is not clear, it is believed that the dispersibility of the primary particles of the copper powder is improved and the particle size distribution of the copper powder is narrowed because D BET / D 50 and the coefficient of variation (SD / MV) are each within a certain numerical range. As a result, it is believed that the packing properties of the particles are improved. There are several advantages associated with improved particle packing properties. For instance, incorporating copper powder with enhanced packing properties into a conductive paste makes it less likely for the wiring obtained from the paste to break. Since improved packing properties mean there are fewer voids between particles, shrinkage is minimal even after firing the conductive paste, making it difficult for the wires to break. In terms of further increasing the filling capacity, the D BET / D 50 of the copper powder of the present embodiment is preferably 0.70 or higher, more preferably 0.75 or higher, even more preferably 0.78 or higher, even more preferably 0.80 or higher, and preferably 1.20 or lower, more preferably 1.10 or lower, and even more preferably 1.00 or lower. In addition, from the perspective of further increasing the fillability, the D BET / D 50 of the copper powder of the present embodiment is preferably 0.70 or more and 1.20 or less, more preferably 0.75 or more and 1.20 or less, even more preferably 0.78 or more and 1.10 or less, and even more preferably 0.80 or more and 1.00 or less. The particle size D BET of the copper powder of this embodiment can be calculated by the following equation (1). In Equation (1), ρ is the density of the copper powder (8.96 g/cm³) and s is the specific surface area of the copper powder by nitrogen adsorption method. In terms of further increasing the filling capacity, the coefficient of variation (SD/MV) of the copper powder of the present embodiment is, for example, 0.01 or higher, and preferably 0.50 or lower, more preferably 0.45 or lower, even more preferably 0.40 or lower, and even more preferably 0.35 or lower. In addition, from the perspective of further increasing the fillability, the coefficient of variation (SD/MV) of the copper powder of the present embodiment is preferably 0.01 or more and 0.50 or less, more preferably 0.01 or more and 0.45 or less, even more preferably 0.01 or more and 0.40 or less, and even more preferably 0.01 or more and 0.35 or less. In terms of improving handling and dispersibility, the D 50 of the copper powder of the present embodiment is preferably 0.1 μm or more, more preferably 0.5 μm or more, even more preferably 1.0 μm or more, even more preferably 1.4 μm or more, and preferably 5.0 μm or less, more preferably 4.7 μm or less, even more preferably 4.5 μm or less, and even more preferably 4.3 μm or less. In addition, from the perspective of improving handling and disp