DOWA HOLDINGS CO., LTD.

Metal Processing

Metal Processing

Metal Processing

Centered on automobiles and information and communication devices, we supply high-performance copper alloys and electroplating services, as well as metal-ceramic substrates, based on alloy control technology, plating film formation and composite technology, and joining technology.

Core Technologies

Copper Alloy Processing Technology

  • Composition Control
    • By performing texture control and precipitate control, we develop copper alloy materials that satisfy the characteristics required in advanced markets (automobiles, high-speed communication, wearables).
  • Precision Rolling and Flatness Control
    • In areas such as autonomous driving and mobile communications to build a smart society, the miniaturization of components is accelerating. The thickness of the material is also very thin (< 100 μm), and it is required to create the thickness and shape with high precision. Therefore, we have introduced the cutting-edge control technologies such as precision rolling technology and flatness control technology.

Surface Treatment Technology (Copper Alloys and Electroplating)

  • Sn Plating
    • We have developed STAR (Super Thin Advanced Reflow) plating that achieves excellent contact reliability and low insertion force. Its performance is very much appreciated by our customers.
  • Silver-Graphite Composite Plating
    • Charging terminals for EVs are required to have low electrical resistance, durability of insertion and removal, and corrosion resistance. We have developed SilC plating®, a brand new Ag-graphite composite plating that meets these requirements at a high level.
    • SilC plating® contains graphite particles in the silver matrix which prevent adhesive wear during insertion and removal of the terminals, which typically occurs on silver.
  • Plating Film Crystal Control Technology
    High Hardness Ag Plating, Low Hardness Ag Plating
    • By controlling the crystalline state of the Ag plating film, each function has been improved.
    • We have developed a plating membrane that meets the needs of automobiles.
  • Micro plating Technology
    Au Spot Plating
    • We have the technology to apply Au plating with extremely high precision and limited areas.

Bonding Technology

  • Active Metal Brazing Technology
    • We have developed metal-ceramic substrates with low thermal resistance and excellent heat-cycle durability using active metal brazing technology.
    • We are engaged in the design of copper-bonded ceramic substrates and the development of bonding technologies to meet the future needs of power modules.
  • Molten Aluminum Direct Bonding Technology
    • We have developed a new bonding method using molten aluminum bonding that achieves few bonding defects and high bonding strength and heat dissipation.
    • We have developed a one-of-a-kind product “Aluminum Base Integrated Substrate” that integrates aluminum circuits, ceramics, base plate, and heat dissipation fins.

Circuit Formation and Surface Control Technology

  • Etching Technology
    • We have circuit formation technology by precision etching.
    • We have shape control technology of circuit cross section for excellent heat-cycle resistance.
  • Surface Treatment Technology
    • We have surface control technologies that realize solderability, wire bondability, and well image recognition.
    • We have surface control technologies that are suitable for sintering process.

Examples of Core Technology Applications

  • Composition and Microstructure Control Technology
    Representative Treatment Process
    Technical Features: Points of Differentiation
    • Melting and Casting: Microstructure control, Preventing contamination with impurities, Preventing Segregation
    • Hot Rolling: Precipitate distribution control, Dynamic recrystallization, Flatness control
    • Cold Rolling: Grain size & orientation control, Thickness control, Flatness control
    • Heat Treatment: Grain size & orientation control, Precipitate distribution control
    Ultrafine Precipitates in Cu Alloys
  • Precision Rolling and Flatness Control Technology
    Representative Treatment Process
    Technical Features: Points of Differentiation
    • Cold Rolling: Thickness control, flatness control, surface roughness control
    • Leveling: In-plane elongation difference control, residual stress control
    • Stress-Relief Annealing: In-plane elongation difference control, residual stress control
    20-High Rolling Mill
  • Reflow Sn Plating Technology
    Typical Treatment Process
    Technical Features: Points of Differentiation
    • Pre-treatment process: Selection of solutions to remove dirt and oxides from the surface of the material, and solution control
    • Sn plating process: Current distribution and stirring of solutions
    • Reflow process: Residual stress removal, diffusion layer, and temperature distribution
    Sn-Plated Product
  • Silver-Graphite Composite Plating Technology
    Typical Treatment Process
    Technical Features: Points of Differentiation
    • Pre-treatment technology
    • Underlayer plating process: Current distribution and stirring of solutions
    • Silver-graphite composite plating process: Current distribution, stirring of solutions, and uniform dispersion of graphite particles
    Silver-Graphite Composite Plating
  • Plating Film Crystal Control Technology
    Representative Treatment Process
    Technical Features: Points of Differentiation
    • By controlling the Ag plating structure, it is possible to distinguish between high and low hardness.
    • Abrasion resistance and heat resistance according to the application.
  • Bonding Technology
    Typical Process: Active Metal Brazing Technology
    Technical Features: Points of Differentiation
    • Characteristics (bonding strength, etc.) have been improved by optimizing brazing material composition, brazing material manufacturing process, brazing material application process, bonding temperature, and bonding atmosphere.
  • Circuit Formation Technology
    Typical Process: Masking and Etching Technology
    Technical Features: Points of Differentiation
    • Highly accurate circuits can be formed by optimizing masking materials, masking application processes, etching solution composition, etching processes, etching conditions, and mask-stripping processes.
  • Surface Treatment Technology
    Typical Process: Plating Technology
    Technical Features: Points of Differentiation
    • We improved the environmental durability by optimizing the plating process, plating solution composition, and plating conditions.
    Cu-AlN Substrate