Quantum Leap: Any-layer HDI Technology of PCBWay

Introduction

PCBWay is a high-end PCB R&D and manufacturing company. Since 2015, the company is keenly aware that the future demand for high-density interconnection boards and high-frequency high-speed boards in communications, medical, industrial control, and other industries will show explosive growth. So we further upgrade and adjustment of product strategy, accurate positioning on HDI high-density interconnect circuit boards, 5G communication high-frequency high-speed circuit boards. On the basis of the gradual and stable production of 1–5 order HDI boards in the past 4 years, the technical center has once again faced the difficulties, and successfully developed a 14-layer 6-stage any-layer HDI board.

Overview of Any-layer HDI Board

At present, China’s 5G communication technology has reached the world’s leading level, and 5G commercialization has been fully rolled out. The 5G communication circuit board is highly integrated and the PCB space cannot be increased, resulting in more dense PCB wiring, narrower wire width and spacing, narrower aperture and center distance, and reduced thickness of the insulating layer. However, the traditional HDI process capability is limited and difficult to satisfy the requirement of 5G.

Therefore, any-layer HDI with more stack-up, smaller line spacing, and more functional modules can become the best solution. From the current stage of development, with the upgrade of 5G mobile phone function modules and the improvement of signal transmission requirements, the integration of internal space and the number of components carried will continue to increase, thus endlessly forcing mobile phone motherboard upgrades. It is estimated that ordinary 5G mobile phones in the future will require at least 8–12 layers of 4-stage HDI motherboards, and the technology of high-end flagship phones will be directly upgraded to any-layer HDI level of 14-layer 5-stage or above. At present, the level of PCBWay’s process has surpassed most domestic private enterprises.

Introduction of key technology of 14-layer 6-stage HDI board:

Any-layer HDI technology has a higher technical threshold. The main processing difficulties are: interlayer alignment, laser drilling, hole-filling electroplating, and fine circuit processing. At present, few domestic manufacturers have high process capability and rapid delivery capability. PCBWay is close to the market, based on the customer’s urgent need for high-level high-stage any-layer HDI bare board, finally successfully developed a 14-layer 6-stage any-layer HDI board in June.

1. HDI stack-up structure analysis:

The conventional products in the industry are 1–3 stage HDI. The more the stage, the greater the probability of layer deviation. Our product is a 14-layer 6-stage board, with a board thickness of 1.6mm and a blind hole structure of 6+N+6 is 1–2, 1–3, 1–4, 1–6, 1–7, 1–9, 1–10, 1–11, 6–10, 6–14, 7–14, 10- 14.12–14,13–14. There are a total of 14 sets of blind holes. The blind holes are interconnected and need to be manufactured according to the 6-stage HDI process. The structure is very complicated and the processing flow is long.

2. Connection method:

The conventional core board is pressed 3 times (multiple presses will result in uncontrolled core board expansion and contraction). While our product needs to be pressed 6 times, through the 0708 layer core board superimposed pressed 6 times, superimposed laser 6 times and electroplating hole filling, of which 0708 layer is 0.15mm through-hole electroplating hole filling, other holes are 0.127mm laser drilling and electroplate filling.

3. Line preamplification coefficient:

6 times of lamination, pre-laying is the key, need to consider the expansion and contraction produced by each lamination, and then give the pre-release coefficient of the initial core board (0708 layer), this coefficient will directly affect the production of the subsequent board.

4. Laser drilling:

After 0609 and 0510, the coefficient after the second lamination is large, and the laser machine and the LDI machine cannot recognize the gripping hole. It is necessary to adjust the laser target of the laser and the parameters of the line LDI machine.

5. Electroplating hole filling:

The number of 0.15mm laser holes is 1200–1800 holes/face, and the area to be plated is small. It is easy for local depressions to be filled when the blocking point is filled, and the laser needs to be repeated 6 times and filled 6 times.

6. Graphic plating:

The line width/distance of the inner layer is 0.075/0.075mm, the pattern distribution in the board is isolated, and the image is easily etched and the line is thin.

7. Production cycle:

20 days to complete the delivery

PCBWay’s Capability to manufacture HDI PCB

1. In order to adapt to the ever-increasing technological development of the PCB industry and meet the needs of customers, PCBWay upgraded the organizational structure of the technical research and development team in 2019. On the basis of the original process department, the technical center was upgraded and established. We established a separate HDI board R&D department and conducted sub-sector management with process technology. The R&D part focuses on the technical research of HDI boards and high-frequency high-speed boards;

2. PCBWay has a strong engineering CAM processing capability. In recent years, we have established an IT information technology team and has continued to invest in CAM automation software development, gradually improving the CAM processing automation system, improving work efficiency, reducing dependence on the personnel. At the same time, we have established a relatively complete CAM engineer performance evaluation mechanism and training system. Through the implementation of the above measures, the project file error rate has been greatly reduced and the CAM processing efficiency has been improved;

3. Invested huge amounts of money to upgrade the equipment. In recent years, we have successfully purchased special equipment for HDI boards such as LDI laser exposure machines, laser drilling machines, electroplating hole filling lines, and deep-controlled drilling machines. Especially in 2019, we eliminated all electroplating equipment at one time, and comprehensive upgrade (including sink copper wire, one copper wire, two copper wire, hole filling line, vacuum SES alkaline etching line, vacuum DES acid etching line, etching online AOI and other equipment ). In addition, in 2020, we are currently planning to upgrade and introduce vertical vacuum resin plugging machine, ceramic grinder, 300℃ high-temperature multilayer board PIN LAM press, high-frequency electromagnetic press fusion machine, HDI optical module plated hard gold plating Advanced equipment, such as cable, is expected to be put into use in the fourth quarter;

4. In the selection of product raw materials, in order to protect the quality of customers’ products at all costs, all international and domestic first-line brands are used. For example, the board is made of high-end materials such as Shengyi, Lianmao, Taiyao, Rogers, Panasonic, and medicine is Rohm and Haas, Atotech, etc. The dry film is Japan’s Asahi Kasei, the United States DuPont, etc. The solder mask is solar ink. High-end materials are used to fully satisfy customers’ requirements for high-end products with high quality and high reliability.