High Frequency Microwave Printed Circuit Board Manufacturing Has Those Characteristics

With the continuous development of science and technology, especially information technology, printed circuit board production process technology to meet the needs of different users. In recent years, communications, automotive and other areas of rapid development, the demand for printed circuit boards has undergone some changes, high-power printed circuit boards, high-frequency microwave boards to increase demand. Microwave printed circuit board, is a specific microwave substrate copper-clad board, the use of ordinary rigid circuit board manufacturing methods to produce microwave devices.

In the printed circuit board wires in the high-speed signal transmission line, currently can be divided into two broad categories: a class of high frequency signal transmission class of electronic products, this class of products is related to the radio's electromagnetic waves, it is a sinusoidal wave to the transmission of signals to products such as radar, radio and television, and communications (cell phones, microwave communications, fiber-optic communications, etc.). Another category is the high-speed logic signal transmission class of electronic products, this type of product is to digital signal transmission, the same is also related to electromagnetic wave transmission of square waves, this type of product began to be mainly in computers, computers and other applications, and now has been rapidly promoted to the application of household electrical appliances and communications on the electronic products.

In order to achieve high-speed transmission, microwave printed circuit board substrate materials have clear requirements in terms of electrical characteristics. In order to improve high-speed transmission, to realize the transmission signal of low loss, low delay, must choose the dielectric constant and dielectric loss angle tangent small substrate materials.

Substrate materials for high-speed transmission generally include ceramic materials, glass fiber cloth, polytetrafluoroethylene, and other thermosetting resins. In all the resins, PTFE dielectric constant and dielectric loss angle tangent is the smallest, and resistance to high and low temperatures and aging performance is good, the most suitable for high-frequency substrate materials, is currently the largest amount of microwave printed circuit board manufacturing substrate materials. Microwave printed circuit board manufacturing characteristics, mainly in the following areas:

Substrate Material Diversification:

For a long time, the domestic application of the most domestic glass cloth reinforced PTFE laminate. However, due to its single species, poor dielectric properties uniformity, has become increasingly unsuitable for some high-performance requirements of the occasion. Into the nineties, the United States Rogers produced RT/Duroid series and TMM series of microwave substrate boards have been gradually applied, mainly glass fiber reinforced PTFE copper cladding boards, ceramic powder filled PTFE copper cladding boards and ceramic powder filled thermosetting resin copper cladding boards, although the price is expensive, but it is excellent dielectric properties and mechanical properties of domestic microwave printed circuit boards substrate still has considerable advantages. Great advantage. At present, this type of microwave substrate, especially with aluminum substrate is being used in a large number of applications.

Design Requirements for High Precision:

Microwave printed circuit board graphics manufacturing precision will gradually improve, but by the printed circuit board manufacturing process method itself, the limitations of this precision improvement can not be unlimited, to a certain extent, will enter a stable stage. The design of microwave boards will be greatly enriched. From the type of view, there will be not only a single panel, double-sided board, there will be microwave multilayer board. The grounding of the microwave plate, will put forward higher requirements, such as a general solution to the Teflon substrate hole metallization, to solve the grounding of the microwave plate with aluminum backing. Coating requirements are further diversified, special emphasis will be placed on the protection of aluminum substrate and coating. In addition to the microwave board of the overall three protection will also put forward higher requirements, especially the PTFE substrate three protection issues.

Computer-controlled:

Traditional microwave printed circuit board production is rarely applied to computer technology, but with the wide application of CAD technology in the design, as well as microwave printed circuit boards of high precision, high volume, in the microwave printed circuit board manufacturing a large number of applications of computer technology has become an inevitable choice. High-precision microwave printed circuit board template design and manufacturing, shape of the CNC machining, as well as high-precision microwave printed circuit board batch production inspection, has been inseparable from computer technology. Therefore, the need for microwave printed circuit board CAD and CAM, CAT connection, through the CAD design of data processing and process intervention, to generate the corresponding CNC machining files and CNC inspection files for microwave printed circuit board production process control, process inspection and finished product inspection.

High-precision Graphics Manufacturing Specialization:

Microwave printed circuit boards of high-precision graphics manufacturing, compared with the traditional rigid printed circuit boards, towards a more specialized direction, including high-precision stencil manufacturing, high-precision graphics transfer, high-precision graphic etching and other related processes, production and process control technology, but also contains a reasonable arrangement of manufacturing process routes. For different design requirements, such as hole metallization or not, the type of surface plating and so on to formulate a reasonable manufacturing process, after a large number of process experiments, optimize the process parameters of the relevant processes, and determine the process margins of each process.

Diversification of Surface Coating:

With the expansion of the scope of application of microwave printed circuit boards, the use of environmental conditions are also complex, and at the same time, due to the application of a large number of aluminum substrate substrate, and therefore the microwave printed circuit boards on the surface of the coating and protection, in the original chemical precipitation of silver and tin cerium alloy plating on the basis of the higher requirements. First, the microstrip pattern surface coating and protection, need to meet the microwave device welding requirements, the use of electroplating nickel and gold technology to ensure that the microstrip pattern is not damaged in harsh environments. This is in addition to the weldability of the surface of the microstrip pattern plating, the main thing is to solve both effective protection without affecting the microwave performance of the three anti-protection technology. Second, the protection of aluminum liner and plating technology. Aluminum liner such as unprotected, exposed to humidity, salt spray environment will soon be corroded, so with the aluminum liner is a large number of applications, its protection technology should attract sufficient attention. In addition to research to solve the aluminum plating technology, plating silver, tin and other metals on the surface of the aluminum liner for microwave device welding or other special purposes in the gradual increase in demand, which not only involves the aluminum plating technology, there is also a microstrip graphic protection issues.

Shape Processing CNC:

Microwave printed circuit board shape processing, especially with aluminum liner microwave printed circuit board three-dimensional shape processing, is a microwave printed circuit board batch production needs to focus on a technology. In the face of thousands of microwave printed circuit boards with aluminum liner, the traditional shape processing method can not guarantee the manufacturing accuracy and consistency, but also can not guarantee the production cycle, and must use advanced computer-controlled CNC processing technology. However, the shape processing technology of microwave printed circuit board with aluminum liner is different from both metal material processing and non-metallic material processing. Due to the common existence of metal materials and non-metallic materials, its processing tools, processing parameters, etc., as well as processing machine tools have great specificity, there are also a large number of technical problems need to be solved. Shape processing process is the longest cycle in the manufacturing process of microwave printed circuit boards a process, so the shape of the processing technology to solve the good or bad directly related to the entire microwave printed circuit board processing cycle length, and affects the product development or production cycle.

Batch Production Inspection Equipment:

Microwave printed circuit boards and ordinary single and double-sided boards and multilayer boards are different, not only plays the role of structural components, connectors, and more importantly, as the role of signal transmission lines. This means that the transmission of high-frequency signals and high-speed digital signals with microwave printed circuit board electrical testing, not only to measure the line (or network) "through" "break" and "short circuit" and so on whether to meet the requirements, but also to measure the characteristic resistance. Compliance with the requirements, but also to measure the characteristic impedance value is within the prescribed range of eligibility. In addition, high-precision microwave printed circuit boards have a large number of data to be tested, such as graphic accuracy, positional accuracy, overlap accuracy, coating thickness, shape and three-dimensional dimensional accuracy. At present, the domestic microwave printed circuit board batch production inspection technology is very backward, the current method is basically based on manual visual inspection, supplemented by some simple measuring tools. This primitive and simple inspection method is difficult to cope with a large number of microwave printed circuit boards with hundreds of thousands of data batch production requirements, not only the long inspection period, and more errors and omissions, thus forcing the microwave printed circuit boards manufacturing to the direction of batch production inspection equipment development.