Gold silver transition through-hole paste

Low temperature co fired ceramic (ltcc) technology is a new type of multi-layer substrate process technology, which has low dielectric constant, low dielectric loss characteristics, and high conductivitymetal conductor(Gold, silver, copper, etc.), with the advantages of easy integration, diverse design, flexibility, and excellent high-frequency microwave performance, is a key technology for designing and manufacturing high-density integrated subsystems or systems such as RF microwave integrated components, modules, and SIP. Ltcc technology has become the most ideal technology for high-density integrated components. With the application of 5G technology, the demand for ltcc microwave passive components (ltcc filters, power dividers, baluns, etc.), millimeter wave filters, and millimeter wave integrated antennas is increasing. Many high-frequency applications require ltcc conductors to have excellent characteristics, including ideal conductivity, weldability, resistance to solder erosion, bonding performance, adhesion, migration resistance, and long-term reliability.
For highly reliable ltcc devices, using highly reliable gold conductors increases the cost of the device. Especially in civilian fields such as communication, cost is one of the important factors to consider, and it is expected to find alternatives to precious metals like gold. One method is to use silver based conductors instead of gold. However, the reliability of silver conductors is relatively low and cannot be bonded with gold wires. In places where gold wire bonding is required or reliable, it is still necessary to use gold conductors and gold vias. For example, the surface of the ltcc substrate requires gold wire bonding and high reliability, while the bottom of the ltcc cavity requires the use of highly reliable gold conductors. Although transition via hybrid conductor technology can be used, the ltcc substrate adoptsSilver through-hole, silver conductorThe surface metal layer uses gold conductors, which to some extent reduces costs. But in ltcc substrates with cavities, high reliability gold conductors are required at the bottom of the cavity, and the bottom of the cavity is often a large area of metal ground layer. If only gold conductors are used at the bottom of the cavity and silver conductors are used elsewhere, there will be a Kirkendall effect in the sintering process where the gold and silver conductors overlap, resulting in voids and reliability issues with interconnection.
Therefore, ltcc substrates above the cavity of the ltcc substrate require the use of gold through holes andGold conductor pasteThis greatly increases the manufacturing cost of ltcc substrates. Therefore, we hope to find a conductor system that can reduce or eliminate the problem of gold silver connection defects.