Method for manufacturing high-thermal-conductivity printed circuit board and printed circuit board

Abstract

The invention discloses a method for manufacturing a high-thermal-conductivity printed circuit board. The method includes the steps of providing a substrate, a bonding sheet and a conducting layer, and sequentially stacking and pressing the substrate, the bonding sheet and the conducting layer into a whole, wherein the substrate comprises at least one first metal layer and a second metal layer, the first metal layer is a copper layer, the second metal layer is an aluminum layer, and the first metal layer is pressed onto the surface of the second metal layer to form a metal composite board. The metal composite board serves as the substrate, the first metal layer of the metal composite board is the copper layer, the second metal layer of the metal composite board is the aluminum layer, the metal composite board, the bonding sheet and the conducting layer are pressed into the whole through the press fit process, therefore, the weight of the substrate can be effectively reduced, the cost can be reduced, and metal coatings in holes or grooves which are formed to enable the conducting layer to be communicated with the substrate are prevented from falling off.

Description

technical field [0001] The invention relates to a method for manufacturing a printed circuit board, in particular to a method for manufacturing a high thermal conductivity printed circuit board, and a printed circuit board manufactured by the method. Background technique [0002] The production of existing high thermal conductivity printed circuit boards mainly adopts the following three methods: [0003] 1. Post-bonding method, using a thermally conductive non-flowing adhesive sheet to laminate the metal substrate and the conductive layer that has been patterned. The heat conduction effect of the printed circuit board produced by this method is poor, because the heat conduction effect of transferring heat to the metal substrate through the thermally conductive adhesive sheet as the intermediate medium is not as good as that of using metal as the intermediate medium or the conductive layer directly contacts the metal substrate. [0004] 2. The soldering method (sweat-solder...

AI Technical Summary

Problems solved by technology

The heat conduction effect of the printed circuit board produced by this method is poor, because the heat conduction effect of transferring heat to the metal substrate through the thermally conductive adhesive sheet as an intermediate medium is not as good as that of using metal as an intermediate medium or the conductive layer directly contacts the metal substrate.

[0004] 2. The soldering method (sweat-soldering), using lead-free high-temperature solder paste to weld the metal substrate and the conductive layer that has been patterned, the heat dissipation effect is better than that of the printed circuit board made by the pressing method, but it requires special fixtures and welding equipment. And it is easy to have defects such as poor welding and voids

[0005] 3. Pre-bonding method, that is, the incoming material is an integrated structure of a conductive layer and a metal substrate, and a circuit pattern is drawn on the metal substrate using a specific process, but this type of printed circuit board can only be made with a single-sided circuit , a narrow range of application

However, if a low-cost aluminum base is used as the metal substrate, especially when it is necessary to make multilayer circuits or the conductive layer and the aluminum base need to be conducted, then the problem of aluminum base metallization will be involved.

However, aluminum is a relatively active metal. In the atmosphere, a thin and dense oxide film is easily formed on the surface of aluminum, and the electrode potential is low. It undergoes substitution reactions with various metal ions in the plating solution. Form a loose and rough contact coating, which seriously affects the bonding strength between the copper coating and the aluminum substrate layer

In addition, aluminum is an amphoteric metal, which is unstable in acid and alkali solutions, and when the ambient temperature changes, due to the difference in expansion coefficient between the aluminum substrate layer and the copper coating, internal stress is easily generated and the copper is damaged. Plating, causing the copper plating to fall off

Copper plating on aluminum substrates is mostly used in the field of hardware electroplating in the prior art. Because its process is different from the potion system and process settings of conventional printed circuit board manufacturers, its application in the field of printed circuit board technology is not yet mature. It needs to be further explored and improved before being used

[0007] To sum up, in order to solve the above-mentioned problems such as poor heat dissipation performance of printed circuit boards, large proportion and high cost of copper base, or easy peeling off of low-cost aluminum base coating, it is urgent to provide a new manufacturing method.

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