Bonded Through-Hole Interconnection Structure Against Moisture Oxidation

The patent uses a composite plating structure with multiple metal layers (e.g., Cu-Ni-Au or Cu-Sn-Ni-Au) on the through hole. The inner Cu layer provides electrical conductivity, intermediate Ni layers provide barrier and adhesion functions, and outer Au layers provide oxidation resistance. This composite material approach simultaneously achieves electrical connection while preventing moisture absorption and oxidation.

The patent applies inert or protective metal layers (such as Au or Ni) that create a chemically inert environment for the underlying Cu interconnection material. These protective layers prevent direct contact between moisture/oxygen and the reactive Cu, effectively creating an inert barrier that prevents oxidation and moisture absorption.

The bonding metal portions use composite plating structures matching the through hole plating (e.g., Cu-Ni-Au). This ensures both strong mechanical bonding between chips and reliable electrical connection, as the compatible material composition provides both adhesion strength and electrical conductivity without material incompatibility issues.

The patent maintains material homogeneity between the through hole plating and bonding metal portions. By using the same or compatible metal layer compositions (Cu-Ni-Au or Cu-Sn-Ni-Au), the system achieves uniform properties that simultaneously satisfy both mechanical bonding strength requirements and electrical connection reliability requirements.

The patent segments the deep through hole formation process into multiple manageable steps: drilling/etching the through hole, forming the Cu inner layer, depositing intermediate Ni layers, and applying outer Au layers. This segmentation makes deep through hole manufacturing feasible by breaking down a difficult single-step process into controllable sequential steps with appropriate plating thicknesses at each stage.

The patent applies preliminary protective and functional layers (Cu inner layer, Ni intermediate layers) before final Au plating. This preliminary action prepares the through hole structure with appropriate adhesion, barrier, and conductivity properties, making the subsequent manufacturing steps easier and ensuring reliability without requiring the entire deep hole to be formed in a single difficult operation.

The side surface conductive films use composite plating structures (Cu-Ni-Au or Cu-Sn-Ni-Au) similar to the through hole plating. The Cu or Sn inner layer provides electrical conductivity on the side surface, while intermediate Ni layers and outer Au layers provide oxidation resistance and moisture barrier functions, simultaneously achieving electrical connection and protection against harmful factors.

The side surface conductive films are covered with inert protective layers (Ni and Au) that create a chemically inert environment. These layers prevent direct exposure of the reactive Cu or Sn conductive material to moisture and oxygen, effectively protecting against oxidation and moisture absorption while maintaining electrical conductivity through the underlying conductive layers.