Quality Management for Multilayer PCB Manufacturers

The multilayer PCB boards processed by multilayer PCB manufacturers are generally system boards, which are thicker, heavier, and larger in unit size than conventional multilayer boards, and the corresponding heat capacity is also larger. The welding high temperature time is long. It takes 50 to 90 seconds at 217°C (melting point of tin-silver-copper solder), and the cooling rate of high-level boards is relatively slow, so the time for reflow soldering test is prolonged. Multilayer PCB manufacturers combine the IPC-6012C standard and industry requirements. Laminates are subject to reliability testing.

Raw materials must be strictly inspected to provide guarantee for subsequent production. When the quality of raw materials is guaranteed, it is necessary to pay attention to the problems that will occur in the production process. The multilayer PCB manufacturers should conduct quality inspection and inspection on each process link of the production process to ensure that each process has work instructions. , in order to facilitate comprehensive control of PCB quality.

After the production of multilayer PCB manufacturers is completed, they must also conduct random inspections. Although quality inspections are carried out in raw materials and production processes, there will still be defects caused by various reasons. Therefore, multilayer PCB manufacturers have completed production. After that, the whole volume of PCB boards will be sampled. Only the qualified rate of the random inspection is allowed to leave the factory. If the qualified rate of the random inspection is not up to the standard, full inspection and maintenance will be carried out, and the quality of each PCB board that will be shipped must be responsible.

Highly Difficult multilayer PCB manufacturers

When multilayer PCB manufacturers design multi-layer boards, the layers should be kept symmetrical, and it is best to have an even number of copper layers. If they are not symmetrical, it is easy to cause distortion. The wiring of the multilayer board is carried out according to the circuit function. When wiring the outer layer, it is required to have more wiring on the welding surface and less wiring on the component surface, which is beneficial to the maintenance and troubleshooting of the printed board. In terms of routing, multilayer PCB manufacturers need to separate the power, ground and signal layers to reduce interference between power, ground and signals. The lines of the two adjacent layers of printed boards should be perpendicular to each other as much as possible or follow oblique lines and curves, but not parallel lines, so as to reduce the interlayer coupling and interference of the substrate.

The production of multilayer circuit boards not only requires high investment in technology and equipment, but also requires the experience accumulation of technicians and production personnel for multilayer PCB manufacturers. At the same time, the customer certification procedures for importing high-level boards are strict and cumbersome, so multilayer circuit boards enter the enterprise. The threshold is high, and the multilayer PCB manufacturers has a long period of industrialized production.

1. Main production difficulties

Compared with the characteristics of conventional circuit boards, high-level multilayer circuit boards have the characteristics of thicker boards, more layers, denser lines and vias, larger unit size, thinner dielectric layers, etc., internal space, interlayer alignment, etc. The requirements for degree, impedance control, and reliability are more stringent.

1.1 Difficulties in inter-layer alignment

Due to the large number of layers in high-level multi-layer boards, customer designs have more and more stringent requirements on the alignment of each layer of the PCB. Usually, the alignment tolerance between layers is controlled to ±75μm. The environmental temperature and humidity of the transfer workshop, as well as the dislocation stacking and interlayer positioning methods caused by the inconsistency of the expansion and contraction of different core layers, make it more difficult to control the interlayer alignment of high multi-layer boards.

1.2 Difficulties in making inner layers

High multilayer boards use special materials such as high TG, high speed, high frequency, thick copper, and thin dielectric layers. Multilayer PCB manufacturers have high requirements for inner layer circuit production and graphic size control, such as the integrity of impedance signal transmission, increasing Difficulty in making inner layers. The line width and line spacing are small, the open and short circuits are increased, the micro-shorts are increased, and the pass rate is low; there are many signal layers of fine lines, and the probability of missed inspection of the inner layer AOI is increased. It is easy to roll the board when the machine is over; most of the high-layer multi-layer boards are system boards, the unit size is large, and the cost of scrapping the finished product is relatively high.

1.3 Difficulties in pressing production

Multiple inner core boards and prepregs are superimposed, and defects such as sliding plates, delamination, resin voids and bubble residues are prone to occur during lamination production. When designing the laminate structure, the multilayer PCB manufacturer needs to fully consider the heat resistance, withstand voltage, glue filling and dielectric thickness of the material, and set a reasonable high-level board lamination program. There are many layers, and the expansion and shrinkage control and size coefficient compensation cannot be consistent; the interlayer insulating layer is thin, which easily leads to the failure of the interlayer reliability test.

1.4 Difficulties in Drilling

Multilayer PCB manufacturers use special boards with high TG, high speed, high frequency, and thick copper, which increase the difficulty of drilling roughness, drilling burrs and drilling contamination. The number of layers is large, the cumulative total copper thickness and plate thickness, and the drilling tool is easy to break; there are many dense BGAs, and the CAF failure problem caused by the narrow hole wall spacing; the inclined drilling problem is easily caused by the PCB thickness.

Development Prospects for Multilayer PCB Manufacturers

The Multilayer PCB Board Industry Research Report contains statistics and analysis of global and Chinese regional multilayer PCB manufacturers data. In 2021, the global market size of multi-layer PCB manufacturers will be 100 million yuan (RMB). In 2021, China will account for % of the global market share. It is expected that the compound growth rate of the Chinese market will be % from 2022 to 2029. The scale of Chinese multilayer PCB manufacturers will reach 100 million yuan in 2029.

The multilayer PCB market report analyzes the current situation of the multilayer PCB manufacturers, the market capacity of the multilayer PCB manufacturers, the market share of the multilayer PCB segment products, the demand for the downstream application industry of the multilayer PCB, the competitive situation of the multilayer PCB manufacturers, the global With detailed information such as the overview of multi-layer PCB manufacturers in China, analyze the development characteristics of multilayer PCB manufacturers at this stage, and identify the main factors affecting the development of the industry, thereby predicting the future development trend of the industry and pointing out the future for multilayer PCB manufacturers Direction of development.

Multilayer PCB processing is difficult, and its quality and reliability requirements are high. It is mainly used in communication equipment, high-end servers, medical electronics, aviation, industrial control, military and other fields. In recent years, the market demand for high-level multi-layer boards in the fields of application communication, base station, aviation, and military is still strong, and with the rapid development of China's telecommunication equipment market, the market prospects of multilayer PCB manufacturers are optimistic.

How to Find Multilayer PCB Manufacturers

1. Whether the multilayer PCB manufacturers has professional equipment. Multilayer PCB manufacturers need very professional equipment during processing and production, such as drilling equipment, testing equipment, etc. are the basis for ensuring production.

2. Whether the multilayer PCB manufacturers have professional process management.

In addition to professional production equipment, PCB prototypes also require process management to professionally control the quality. Better multilayer PCB manufacturers will be certified by ISO9001 quality management system, UL, RoHS, REACH standards, etc., and will guide employees' behavior through work instructions and other information documents. By viewing the information documents and qualification certification of the multilayer PCB manufacturers, you can get a general understanding of the quality control strength of the multilayer PCB manufacturers.

3. Whether the multilayer PCB manufacturers have a complete inspection process. In addition to professional equipment and professional process management, multilayer PCB manufacturers must also have complete testing procedures. We all know that PCB prototype is a delicate job, the whole process is complicated, and the quality may be problematic. Therefore, it is necessary to check the layers, strictly check the quality defects, and "check the gaps and fill the gaps.