Silver-based circuit board chemically plated with nickel, palladium and gold and preparation method of silver-based circuit board

Abstract

The invention discloses a silver-based circuit board chemically plated with nickel, palladium and gold and a preparation method of the silver-based circuit board. The silver-based circuit board comprises a silver-based substrate, wherein a nickel layer, a palladium layer and a gold layer are sequentially plated on the surface of the silver-based substrate from inside to outside. The preparation method comprises the steps of sequentially carrying out pretreatments of micro etching, acid pickling, pre-pickling, palladium activation and post-pickling on the cleaned silver-based substrate, and then sequentially carrying out chemical nickel plating, chemical palladium plating and chemical gold plating on the pretreated silver-based substrate to obtain the silver-based circuit board with the nickel, palladium and gold plating layers. Compared with the traditional chemical plating of nickel, palladium and gold on a copper-based substrate, the thickness of the nickel, palladium and gold plating layers can be greatly reduced, so that the use content of the metal is saved, and the problem of environmental pollution is avoided; and in addition, the substrate is silver-based, so that the wholecircuit board is higher in electrical conductivity and thermal conductivity, higher in sensitivity, longer in service life, and more excellent in overall performance.

Description

technical field [0001] The invention relates to a silver-based circuit board with electroless nickel-palladium-gold plating and a preparation method thereof, belonging to the technical field of surface treatment technology. Background technique [0002] With the rapid development of the electronics industry, the demand for circuit boards is increasing day by day. However, today's electronic products have gradually developed towards the direction of multi-function, high performance, portability, reliability and low cost. In order to meet the needs of the market and technology, it is not only required that the electronic packaging process must move towards high-density packaging such as system packaging or IC packaging. There is a need for a coating that can meet a variety of packaging processes, so the "universal" reputation of the electroless nickel-palladium-gold surface treatment process is born from this. [0003] The main processes of electroless nickel palladium platin...

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Problems solved by technology

[0004] At present, the commonly used electroless plating substrate is copper base, but the copper base after microetching treatment is easily polluted and oxidized by the environment.

At the same time, the use of copper-based substrates generally requires a thicker nickel layer and palladium layer to prevent the oxidation of the copper-based substrate and prevent the diffusion of copper ions to the gold layer and migration to the surface of the circuit board, causing poor solderability of the product.

Furthermore, considering factors such as its performance and production cost, many people choose the electroless nickel plating process instead of the electroless gold plating process. However, the electroless nickel plating process has poor bonding ability to gold wires, and it is difficult to form a competitive advantage and be promoted.

However, the pure chemical gold plating process causes a large amount of precious metals to be used, which not only wastes costs, but also easily pollutes the environment.

[0005] Compared with copper-based, silver-based has much better electrical conductivity, thermal conductivity, and sensitivity. It is expected to produce high-quality circuit boards with good electrical conductivity, thermal conductivity, high sensitivity, corrosion resistance, and strong oxidation resistance. However, currently In the prior art, there is no process for electroless nickel-palladium-gold plating with silver base as the substrate

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