The influence of glass phase precipitation in thick film substrate gold conductor paste on bonding

Thick film substrate gold conductor pasteGlass is a special material combination consisting of a gold conductor paste and a glass substrate. The characteristics of this material are high reliability, high density, and high precision, which can be applied in the manufacturing of electronic components.

In the manufacturing process, the first step is toGold conductor pasteCoat on a glass substrate to form a uniform metal layer. Then, through high-temperature heating treatment, the metal layer is tightly bonded to the glass substrate, forming a hard, wear-resistant, and corrosion-resistant thin film. This film has excellent conductivity and mechanical strength, and can be used to manufacture high-performance electronic components.

The advantages of thick film substrate gold conductor paste glass are its high reliability and high density. Due to the extremely thin thickness of the metal layer, the integration and performance of the circuit board can be improved without increasing its volume. At the same time, the hardness and wear resistance of the metal layer are also very good, which can ensure the long-term stability and reliability of electronic components.

In addition, thick film substrate gold conductor paste glass also has the characteristic of high precision. Due to the extremely thin thickness of the metal layer, precise thickness and shape of the metal layer can be achieved by controlling the coating process and heating treatment conditions. This makes this material suitable for manufacturing high-precision, high-quality electronic components such as microprocessors, memory, etc.
The appearance of glass phase separation is closely related to the type of slurry and the number of sintering times of the slurry The main components of the glass phase are O, Zn, Al, Si, Pb, and Ca. The glass phase hinders the diffusion of Au Al elements during the bonding process, reducing the effective bonding area between the bonding point and the gold layer, which is not conducive to bonding The glass phase precipitated after sintering reduces the reliability of AlSi wire ultrasonic bonding, and in severe cases, can cause circuit interconnect failure Therefore, in order to improve the bonding reliability of hybrid integrated circuits, when matching the AlSi wire ultrasonic bonding process, the precipitation of glass phase can be used as a key indicator for selecting the slurry type, and only the slurry type without glass phase precipitation after sintering can be selected to prepare thick film substrates

Au conductor pasteIt is mainly used for high reliability or multi-layer wiring circuits, microwave hybrid integrated circuits, and circuits that are compatible with thin film technology. It can also be used as a solder pad for die bonding or wire bonding. The current achievable line width and line spacing for Au paste printed wires in various conductor pastes is 50-70m. However, the adhesion strength between the film and the substrate decreases during repeated firing of ordinary Au conductors with glass bonding, which can also deteriorate the surface welding performance of the glass floating on the film.

Unglazed Au conductorMetal oxides such as TiO2, CuO, and CdO are used instead of glass as the bonding phase. During firing, these oxides react chemically with the alumina substrate to form spinel type compounds such as CuAl2O4 and CdAl2O4, which act as bonding agents. The unglazed Au conductor does not have the disadvantages of ordinary Au conductors during multiple sintering, and the wiring pattern will not change due to glass softening. The film is also easy to bond wires or chips without glass. In unglazed Au conductors, Au accounts for 90~95wt of the powder and requires a high temperature of 950 ℃~1000 ℃ for firing. In order to improve the poor adhesion strength of ordinary Au conductors, a certain amount of Pd is added to Au to form Au Pd conductors.
Au Pd based conductors not only have high adhesion strength and good weldability, but also can be fired simultaneously with Pd Ag based resistors to form low-noise contacts. The main components in the Au Pd conductor paste can be taken as follows: Pd is 8-15wt%, Au is 73-80wt%, and glass accounts for 12-19wt%. Au Pt and Au Pd Pt based conductor materials are suitable for highly reliable applications such as military and aerospace. Au Pt based conductors are easy to tin and are an excellent resistance termination material, but they are expensive.