Doosan

As the electronics industry continues to develop, electronic devices and components also continue to get lighter, thinner and smaller. To meet this trend in the industry, printed circuit boards with more complex and higher density wiring are in demand. Additionally, the design of thinner, high-density CCL (Copper Clad Laminate) has become an even more important factor to consider.

With the shift from 4G to 5G, data are able to be transmitted at faster volumes and higher volumes. In this 5G environment, data must be transmitted in high volumes at fast and stable speeds even over high-frequency bandwidths. In order to achieve this, faster copper clad laminate signal transmission speeds and low signal loss are required.

Doosan RCC (Resin Coated Copper) materials deliver a thinner and more high-density structure that provides an advantageous substrate solution with reduced signal noise.

1. A Thinner Solution

Thinner RCC material offers a much-anticipated benefit. When it comes to glass fabric prepreg, there are a number of limitations. In order to create a thinner substrate, thinner glass fabric is a prerequisite. But, the rising cost of raw materials makes it difficult to satisfy supply and demand requirements.

Another challenge for creating a thinner substrate is implementing a thinner butter coat* while maintaining high reliability. RCC provides a thinner layer with non-glass fabric with a structure that is only 60% of ordinary prepreg while maintaining the same level of reliability.

*Butter Coat: Resin coating between the glass fabric and copper pad layers or patterns

2. Signal Noise Reduction

The glass fabric in typical prepreg has glass yarn woven into it and creates regions with overlapping glass yarn, regions with windows between the yarn and regions with only glass yarn. This structure results in each region having different electrical characteristics and can cause signal noise.

Depending on the density of the glass fabric, changes in the Dk values can occur, resulting in differences in signal transmission speeds due to differences in Dk values. These differences in transmission speeds ultimately result in signal noise, creating transmission speeds that are not suited for a 5G environment and producing signal loss.

However, with RCC, the uniform compound structure of the insulation layer provides higher reliability and reduces signal noise. As a result, we can expect products to perform similarly as they were originally designed with less effort spent on product optimization.

3. High-Density Design

When the thickness of the insulation layer is reduced with RCC, there is no via-fill plating limitation even if the laser via size is reduced. With RCC, the insulation layer is 40% thinner than the substrates used in most current smart devices and the laser via size is reduced by 30%. We can also expect to see a reduction in the aspect ratio of about 20%.

Thanks to the smaller laser via size, it is possible to reduce the laser via pad size and implement more patterns from the same pitch design allowing a greater degree of freedom in product design. Not only can we reduce overall thickness with a thinner insulation layer, but also make the substrates thinner by reducing the number of layers. Furthermore, as plating layers become thinner, more uniform copper plating becomes possible and is more suitable for creating fine patterns and stable patterns.

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