High-reliability hybrid circuit printed board and production method thereof

Abstract

The invention discloses a high-reliability hybrid circuit printed board, which is provided with a pattern circuit area, a chip mounting area and a green oil assembly welding area, wherein the patterncircuit area is composed of a brazing area and a gold plating area, the brazing area is formed by bonding an insulating base material layer, a copper layer and an OSP film layer which are sequentiallyarranged in the direction from bottom to top, and the gold plating area is formed by bonding an insulating base material layer, a copper layer and a gold plating layer which are sequentially arrangedin the direction from bottom to top. The invention also discloses a production method of the printed board. The invention has the beneficial effects that thick gold is plated in a non-welding area toensure the reliability of gold wire bonding, OSP treatment is adopted for a brazing pad, the tin soldering property of the pad is ensured, the welding end of the printed board is free of a gold plating layer, gold removal is not required to be performed on the brazing pad, the bonding process and the brazing process are completely compatible, and printed board can be applied to high-reliability products; and the process difficulty of gold removal is effectively solved, the use amount of gold is reduced, the processing cost is reduced, and the welding end of the printed board is coated with OSP.

Description

technical field [0001] The invention relates to the technical field of printed circuit board processing, in particular to a highly reliable hybrid circuit printed board and a production method thereof. Background technique [0002] Gold is widely used in the electronics industry because of its advantages such as good chemical stability, not easy to oxidize, good weldability, wear resistance, good electrical conductivity and low contact resistance. Gold plating of printed boards is a good surface treatment method, but there is also a certain reliability risk problem during the soldering process, that is, the "gold brittle" phenomenon. Due to the complexity of product assembly, high-reliability hybrid printed circuit boards involve mixed assembly processes such as gold wire bonding and soldering. The gold plating thickness of the printed board of the gold wire bonding process is generally more than 2 μm to ensure the reliability of the bonding point, while brazing is just the...

AI Technical Summary

Problems solved by technology

b. Poor operability: 1. It is not easy to operate the large grounding pad with fast heat dissipation, and the pad is not easy to level after gold removal, which affects the surface mount assembly of the printed board; 2. For micro-assembly process and brazing process at the same time The hybrid circuit, the distance between the bonding point and the soldering point is relatively close (2mm or less), and it is almost impossible to enamel and remove the gold

c. High risk of reliability: 1. Soldering tin enamel will form a layer of intermetallic compound (SnCu alloy) on the surface of the soldering end. There will be a welding process after the printed board. When the intermetallic compound is too thick (> 4μm), Reduced solder joint strength

2. The printed board pads have been tinned and soldered many times, and there is a risk of separation between the pads and the printed board base material

3. The gold removal effect is not easy to detect (detected by elemental analysis), it may not be thorough

However, there is a risk of thicker intermetallic compounds in HASL. Mixed circuits cannot be used due to the need for gold wire bonding, and the cost is also high. At the same time, due to the skin effect of high-frequency microwave boards, tin plating on microstrip boards affects product performance indicators.

[0006] The method of removing gold from the solder end of printed circuit boards is low in efficiency, difficult to operate (or impossible to operate), and has certain reliability risks. It is difficult to apply to mass production and assembly of high-reliability products.

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