Ceramic Multilayer PCB for Motor Control

Multilayer PCB Lamination

The control of lamination quality is becoming more and more important in multilayer PCB fabrication. Therefore, it is necessary to ensure multilayer laminate quality, need to have a good understanding of multilayer laminate technology. According to the processing practice for many years, Rocket PCB summarizes how to improve the laminating quality of multilayer boards as follows,

• The thickness of the core board should be selected according to the total thickness requirements of the multilayer board. The thickness of the core board should be consistent and the deviation is small.
• There should be a certain distance between the overall dimension of the core board and the effects unit, that is, the distance from the effective unit to the edge of the board should be on the premise of not wasting materials try to keep more space.
• Design of positioning hole. In order to reduce the deviation between layers, attention should be paid to the design of positioning holes in multi-layer boards: 4-layer multilayer only needs to be designed more than 3 positioning holes can be used for drilling. For multi-layer boards with more than 6 layers, in addition to designing positioning holes for drilling, it is also necessary to design more than 5 overlapping positioning rivet holes and more than 5 positioning holes for the tool plate for rivets.
• The inner core board shall be free from the open, short, open circuit, oxidation, clean board surface, and no residual film.
• Meet the requirements of PCB users, select the appropriate PP and copper foil configuration. For 4-ply laminates, 7628, 7630 or 7628 + 1080, 7628 + 2116 can be used etc. 1080 or 2116 is the main choice of PP for multilayer boards with more than 6 layers, and 7628 is mainly used to increase the thickness of the dielectric layer. At the same time, PP requires symmetrical placement to ensure mirror effect and prevent plate bending.
• Inner core board pretreatment process. The treatment process of the inner layer core board includes the black oxidation process and browning treatment process. The oxidation treatment process is to form a black oxide film on the inner copper foil, the thickness of the black oxide film is 0.25-4.50mg/cm2. The browning process (horizontal browning) is to form an organic film on the inner copper foil.

The functions of the inner laminate treatment process are as follows:

• Increasing the surface ratio of inner copper foil and resin can enhance the adhesion between them.
• The effective wettability of the melt resin to copper foil is increased so that the flowing resin has sufficient ability to penetrate into the oxide film and show a strong grip after curing.
• It can prevent the decomposition of dicyandiamide in liquid resin at high temperatures and influence on the copper surface.
• It can improve the acid resistance and prevent the PINK ring in the wet process.

7. The organic matching of lamination parameters, the control of multi-layer board lamination parameters mainly refers to the organic matching of lamination "temperature, pressure, and time". How to determine the lamination temperature, pressure, and time software parameters is the key technology for multilayer laminate processing.

Materials for making multilayer PCB

Copper foil

Basic material composed of the conductive pattern

Core board

A framework of the circuit board, double-sided copper clad board, which can be used for double-sided board production.

Prepreg

The indispensable material for multilayer board production and the adhesive between core board and core board plays an insulating role at the same time.

Various types of most commonly used FR-4 prepreg materials

How to make multilayer PCB?

Multilayer PCB flow-Main processes

Inner Layer Pre-processing

Paste Dry film Para-position Exposure Developing

Etching Strip film Inner layer AOI Lamination

After Lamination Drilling PTH Panel Plating

The purpose of the plating process is to thicken the copper thickness in the hole to prevent the hole copper from being insufficient and causing micro corrosion. The copper thickness in all holes of the working panel is 5 ~ 10 um, and the surface copper thickness is increased by 5 ~ 10 um

Pattern transfer----Exposure---Develop ( Same as inner layer process)

Pattern Plating (Plating copper and Tin)After Pattern plating After Pattern plating Strip film

Etching Strip Tin Soldermask Silksreen

Immersion Gold/Tin/Silver Routing ET/Fixture test Inspection

Package

Difference between single layer and multilayer PCB

Compared with a double-layer board, the multilayer PCB has greatly improved electromagnetic compatibility.

For example, in a four-layer board, the middle layer is used as a power layer and a ground layer, and the benefits of doing so are as follows,

• The inductance of the power wire and ground wire is greatly reduced, thus reducing the noise voltage
• The power supply layer and ground layer form a large distributed capacitor, which provides a good high-frequency decoupling effect for the power supply, thus reducing the noise on the power cord.
• Independent power and ground layer can minimize the area of all signal loops
• PCB multilayer board is the trend of the circuit board industry, the circuit board industry is developing toward a smaller size, the smaller the hole, the thinner the thickness, the larger the number of layers, the smaller the line width and spacing, and so on.
• Many high-precision high-tech electronic products are required multilayer PCB boards to achieve functions, the ordinary double-sided board simply cannot replace them.

Types of multilayer boards

According to usage

it can be divided into

• Civil printed circuit board (consumer electronics such as TV sets, electronic toys, etc. )
• Industrial printed boards (computers, instruments, etc. )
• Printed circuit board for military & Aerospace

According to hardness

it can be divided into

• Rigid PCB
• Flexible board
• Rigid-Flex PCB

According to the conduction state of the hole

it can be divided into

• Buried hole board
• Blind hole board
• Blind buried PCB &HDI PCB
• Through-hole PCB

Classification by substrate

• Glass cloth-based printed circuit board---FR4 material
• Printed circuit board with ceramic substrate
• Metal core-based printed circuit board

Application of Multilayer PCB

As mentioned above, multilayer PCB can be used in civil, industrial, and military fields. Multilayer PCB can be used for any purpose.

For many industries, multilayer PCB has become the first choice for various applications. This preference is largely due to the continuous promotion of mobility and functionality by all technologies. Multilayer PCB is a reasonable step in this process, which can reduce the size and realize more functions. As a result, they have become quite common, including:

• Consumer electronics: consumer electronics is a broad term, such as smartphones and microwave ovens. Each of these consumer electronics products contains PCB, but more and more of them use multilayer PCB instead of standard single-layer PCB, which is used to increase function and reduce size.
• Computer electronics: everything from the server to the motherboard uses multilayer PCBs, mainly because of their space-saving and high functionality. For these applications, performance is one of the most basic characteristics of PCB.
• Telecommunications: telecommunications equipment typically uses multilayer PCBs in a variety of general applications, such as signal transmission, GPS, and satellite applications. The main reason is its durability and functionality.
• Industrial: Multilayer PCB has become popular in several industrial applications, the most notable of which is industrial control. From industrial computers to control systems, multilayer PCBs are used to run machines throughout manufacturing and industrial applications, contributing to their durability and small size.
• Medical devices: electronic products are becoming an increasingly important part of the healthcare industry, playing a role in every corner of the industry, from treatment to diagnosis. Compared with single-layer substitutes, multilayer PCB is particularly popular in the medical industry because of its small size, lightweight and powerful functions. These advantages make multilayer PCB used in modern X-ray equipment, cardiac monitor, CAT scanning equipment, and medical test equipment.
• Military and national defense: multilayer PCBs are favored in terms of durability, functionality, and low weight, and are very useful in high-speed circuits, which are getting more and more attention in military applications. As the defense industry moves towards highly compact engineering, they are also favored, as smaller multi-layer PCBs leave more space for other components to perform their existing functions.
• Automobile: in the modern automobile, the automobile is more and more dependent on electronic components, especially with the rise of an electric vehicles. From GPS and onboard computers to headlight switches and engine sensors controlled by electronic devices, using the right type of components is becoming increasingly important in vehicle design. Multilayer PCB has high function and relative heat resistance, so it is very suitable for the interior environment of automobiles.
• Aerospace: like cars, jets, and rockets, they rely heavily on modern electronics, all of which have to be very precise. From the computer used on the ground to the computer used in the cockpit, the application of aerospace PCB must be reliable. In this case, multilayer PCB is the ideal solution, with enough protection layer to keep heat and external stress from damaging the connection, and the ability to be made of flexible materials. Their higher quality and functionality also contribute to this utility in the aerospace industry, as aerospace companies prefer to use the best materials to ensure the safety of personnel and equipment.
• There are more! Multilayer PCB is used in a variety of other industries, including the science and research industry, even household appliances and safety. All devices, from alarm systems and optical fiber sensors to atomic accelerators and weather analysis equipment, use multilayer PCBs, making full use of the space and weight saved by this PCB format.

Rocket PCB Solution Ltd is widely known as a professional PCB supplier in the electronic manufacturing industry. We have years of experience in the multilayer PCB, HDI PCB segments. Rocket PCB further expands its range of products including rigid, rigid-flex, HDI, any layer, Flex, large-size, embedded, RF, LED, backplane, the metal substrate, a ceramic substrate, IC structure, high-frequency, heavy copper. High quality and high reliability.

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How to design multilayer PCB

In designing Multilayer PCB, one of the most important things is to plan the stack of Multilayer PCB to achieve the best performance of the product. The bad design of the substrate and improper selection of materials will reduce the electrical performance of the signal transmission, increase emission and crosstalk, and make the product more v