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JP-7857451-B2 - Aluminum nitride sintered bodies and electronic components

JP7857451B2JP 7857451 B2JP7857451 B2JP 7857451B2JP-7857451-B2

Inventors

  • 伊藤 冬樹
  • 高橋 光隆

Assignees

  • 株式会社MARUWA

Dates

Publication Date
20260512
Application Date
20250131

Claims (6)

  1. An aluminum nitride sintered body comprising aluminum nitride particles and a sintering aid phase, and having a substrate shape of a predetermined thickness , The thermal conductivity, when converted to a thickness of 2.5 mm, is 240 W/mK or higher , and the dielectric strength is 20 kV/mm or higher. An aluminum nitride sintered body characterized in that the Y₂O₃ content in the sintered body is 0.1% by weight or less, and the carbon content in the sintered body is 0.05% by weight or less.
  2. An aluminum nitride sintered body comprising aluminum nitride particles and a sintering aid phase, and having a substrate shape of a predetermined thickness, The thermal conductivity when converted to a thickness of 2.5 mm is 240 W/mK or higher, and the volume resistivity is 5.0 × 10⁻⁶ 13 It is greater than Ω·cm, Y in the sintered body 2 O 3 An aluminum nitride sintered body characterized by having a content of 0.1% by weight or less, and a carbon content of 0.05% by weight or less in the sintered body.
  3. The aluminum nitride sintered body according to claim 1 or 2 , characterized in that the carbon content in the sintered body is 0.03% by weight or less.
  4. The aluminum nitride sintered body according to claim 1 or 2 , characterized in that the relative permittivity is 8.5 or less and the dielectric loss tangent is 0.001 or less.
  5. The aluminum nitride sintered substrate according to claim 1 or 2 , characterized in that the L * value, which represents the average value of brightness measured at one central point and four corner points, is 57 or more.
  6. An electronic component comprising an aluminum nitride sintered body according to claim 1 or 2 , and a laser diode mounted on the surface of the aluminum nitride sintered body.

Description

This invention relates to an aluminum nitride sintered body, a method for producing the same, and an electronic component. Aluminum nitride sintered bodies are made of insulating materials with high thermal conductivity and are attracting attention as materials for high thermal conductivity substrates. Due to their excellent thermal conductivity, aluminum nitride sintered bodies are widely used as heat dissipation substrates for electronic components such as power transistor module substrates, light-emitting diodes, IC packages, and laser diodes in semiconductors and electronic devices where operation becomes unstable at high temperatures. In recent years, aluminum nitride sintered body substrates have been widely used in electronic circuit boards for mobile applications, and even higher heat dissipation is required. Therefore, various attempts are being made to improve the thermal conductivity of aluminum nitride sintered bodies. For example, Patent Document 1 discloses an aluminum nitride sintered body and a method for manufacturing the same. The aluminum nitride sintered body of Patent Document 1 has a high thermal conductivity of 260 W/m·K or more by specifying the constituent components and content ratio of the grain boundary phase, as well as the microstructure, specifically the average diameter, minimum diameter, maximum diameter, and number of aluminum nitride crystal particles. The method for producing this aluminum nitride sintered body is characterized by comprising: a molding step of mixing aluminum nitride powder having an average particle size of 1.5 μm or less with a sintering aid containing at least Y compound powder and molding to obtain a molded body; a degreasing step of degreasing the molded body; a deoxidation step of heat-treating the degreasing molded body in a non-oxidizing atmosphere or a reduced-pressure atmosphere at 1300°C to 1550°C to deoxidize it; a sintering step of heat-treating the deoxidized molded body in a non-oxidizing atmosphere at 1800°C to 1950°C to obtain a primary sintered body with a thermal conductivity of 230 W/m·K or more; and a reduction step of heat-treating the primary sintered body in a weakly reducing atmosphere at 1750°C to 1900°C to obtain a high thermal conductivity aluminum nitride sintered body with a thermal conductivity of 260 W/m·K or more. In particular, in the sintering step, a primary sintered body with a thermal conductivity of 230 W/m·K or more is obtained by heat-treating the deoxidized molded body in a non-oxidizing atmosphere at 1800°C to 1950°C. In the subsequent reduction process, the primary sintered body is heat-treated in a weakly reducing atmosphere at a temperature between 1750°C and 1900°C to obtain an aluminum nitride sintered body with a thermal conductivity of 260 W/m·K or higher (high thermal conductivity aluminum nitride sintered body). This reduction process removes the grain boundary phase, which is an inhibitory factor in thermal conductivity, by precipitating it on the surface, ultimately yielding an aluminum nitride sintered body with a thermal conductivity of 260 W/m·K or higher. Japanese Patent Publication No. 2011-37691 A schematic diagram showing an example of the reduction firing process in one embodiment of the present invention.A schematic diagram showing an example of the reduction firing process in conventional examples (Comparative Examples 1 and 2).A graph showing the relationship between the brightness L * value and dielectric strength of aluminum nitride sintered bodies (Examples 1-20, Comparative Examples 1-6).A schematic diagram showing electronic components of one embodiment of the present invention. An aluminum nitride sintered body according to one embodiment of the present invention has a substrate shape of a predetermined thickness and can be used as a circuit board for mounting electronic components. Furthermore, the aluminum nitride sintered body is made by sintering 90 to 99.5% by weight of aluminum nitride and 0.5 to 10% by weight of a sintering aid as the main raw material. The aluminum nitride sintered body is composed of a crystalline phase of aluminum nitride particles and a liquid phase consisting of the sintering aid phase. The sintering aid can be selected from the group of oxides of rare earth elements Y, La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, and Yb. In this embodiment, yttrium oxide ( Y₂O₃ ) was used as the sintering aid. It is known that adding rare earth oxides as sintering aids lowers the liquid phase formation temperature during sintering, densifies the crystal structure, and as a result, can achieve both relatively high thermal conductivity and mechanical strength. The aluminum nitride sintered body of this embodiment is characterized in that the Y₂O₃ content remaining in the sintered body is 0.1% by weight or less, and the carbon (element C) content remaining in the sintered body is 0.05% by weight or less. It is more preferable that the Y₂O₃ content is 0.03% by weight or less. It is als