Binding method for lifting soft-solid synthetic printed circuit board via hole trust degree

Abstract

This invention relates to a method to improve the via reliability of soft-hard synthetic PCB, which is mainly to produce the copper coating on the surface of soft PCB substrate to be the electrical wiring through the photolithography and etching method, and then affix the membrane which has been drilled at the predetermined position and has larger diameter compared with via onto the soft PCB in the way of hot-pressing, affix rigid PCB that pre-forms electrical wire onto the membrane in the way of hot-pressing, drill via at the set position by tools, and process procedures of chemical deposition of copper and electroplating on via. Thus, because the diameter of pre-hole is more than that of via, the agent layer contained by the membrane does not be corroded seriously by chemical to enable the chemical corroding copper deposit on the inner wall of via equally avoiding copper tumor or breaking hole formed on the surface of via and improving the performance of circuit boards.

Description

technical field [0001] The invention relates to a method for manufacturing a printed circuit board, in particular to a method for combining hard and soft composite printed circuit boards to improve the reliability of via holes. Background technique [0002] Press, because of Flexible Printed Circuit Boards (FPC for short), it has the characteristics of light weight, thin and small, bendable, low voltage, low power consumption...etc. Since the product can change shape according to the space design, and can be folded and prevent electrostatic interference, the components of its application products can be high-density, and then the volume is reduced, and the weight is also greatly reduced. Therefore, it began to replace some traditional rigid printed circuit boards, and It is used in satellite, medical, industrial and commercial purposes. In the past ten years, due to the rapid development of information and consumer electronics products, under the emphasis on high function, ...

AI Technical Summary

Problems solved by technology

[0006] Please refer to Figure 2d and 2e, and then sandwich the flexible printed circuit board between two rigid printed circuit boards, and use the glass fiber film layer 73 to place the flexible printed circuit board Rigid printed circuit boards are thermally bonded to form a soft-hard combination board, and then the via hole 110 is drilled by mechanical drilling, and then the via hole 110 is subjected to copper plating and copper through-hole plating (PlatingThrough Hole) procedures, and finally The electrical circuit layer 72 is formed by photolithography and etching to form the outer electrical circuit of the rigid circuit board. However, before the chemical copper treatment, the via hole wall will be cleaned with a chemical solution containing permanganate ions. , because the corrosion resistance of the adhesive (EPOXY glue or acrylic glue) layer 802 in the cover film 80 of the flexible printed circuit board is poorer than that of the glass fiber film layer 73 of the rigid printed circuit board, so that the cover film 80 Adhesive (EPOXY glue or acrylic glue) layer 802 of the adhesive agent (EPOXY glue or acrylic glue) layer 802 is bitten too deep, so the copper chemical solution cannot penetrate deep, resulting in the copper chemical cannot be evenly deposited on the inner wall surface of the via hole 110, and the copper chemical defect cannot be produced. Conduction, and then cause copper bumps or holes during copper plating. During the final inspection of the product before shipment or when the customer tests the reliability of the finished product, the signal cannot be transmitted, conduction or poor contact, etc., resulting in a decline in product yield.

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