Six-layer high-density multilayer circuit board

CCL is mainly divided into three parts: First, high frequency; next, high speed; and third, ordinary. This classification is primarily based on the following three elements: Df dielectric loss: the loss situation of electrical signals within the material; Dk dielectric constant: the delay situation of electrical signals within the material; Tg glass transition temperature: the heat resistance of CCL. The basic criteria are as follows: Df < 0.005: high frequency; Df between 0.005 and 0.01: high speed; Df > 0.01: ordinary (low speed). Higher-grade CCLs have lower Df/Dk values, resulting in less loss and delay, higher technical requirements, and greater added value. As a result, profit margins and unit prices naturally increase. Further classification results in a total of six parts. Automotive applications are classified as high-frequency CCLs due to their relation to safety, along with 5G. High-speed CCLs are used in servers and switches, while ordinary CCLs are generally used in consumer electronics. The main advantages of high-frequency CCLs are: high efficiency, fast speed, good adjustability, and strong durability. In the manufacturing process, resin, catalyst, and curing agent are first mixed and then applied to glass fiber cloth. This is bonded with PP and covered with copper foil to form the so-called copper foil substrate. In terms of cost ratio, CCL accounts for about 67% of the total PCB cost, and this cost ratio is relatively high.