As far as the current development status and trend of international electronic circuits are concerned, the development prospect of PCB is very broad, but we will inevitably encounter some mistakes in the process of PCB design. This article will show you the development prospect of PCB and some common mistakes. Will you make these mistakes? Knowing these errors before they affect the overall function of the circuit board is a good way to avoid costly production delays.
First of all, look at the development prospects and trends of PCB:
1. Chip-scale package CSP will gradually replace TSOP and common BGA.
CSP is a chip-level package. It is not a separate package form, but a chip-level package whose chip area can be compared with the package area. CSP package can make the ratio of chip area to package area exceed 1∶, which is quite close to the ideal situation of 1∶1, which is about 1/3 of that of ordinary BGA. The central pin form of CSP package chip effectively shortens the transmission distance of signal, and its attenuation decreases accordingly, and the anti-interference and anti-noise performance of the chip can also be greatly improved. In CSP package mode, the chip particles are welded on the PCB board by solder balls. Because the contact area between the solder joint and the PCB board is large, the heat generated by the chip in operation can be easily conducted to the PCB board and dissipated.
Development prospect: Chip-level package developed in response to the lightness, thinness, shortness and smallness of electronic products is a new generation of packaging methods. According to the development trend of electronic products, chip-level package will continue to develop rapidly, and gradually replace TSOP(ThinSmallOutlinePackage) package and common BGA package.
Second, by 2010, the output value of photovoltaic panels will increase by 14% annually.
Photoelectric board, namely photoelectric backplane, is a special printed circuit board with built-in optical path, and it is also a kind of backplane, which is mainly used in the field of communication. The main advantages of photoelectric backplane: low signal distortion; Avoid noise; Very low crosstalk; Loss is independent of frequency; Dense wavelength multiplexing technology: 12-6 channel multiplex connector; Multi-channel connector; Improve the reliability of discrete cables; The number of photoelectric boards can reach 20, with more than 20,000 lines and 1,000 connectors; Because the traditional backplane uses copper wires, its bandwidth is limited to some extent.
Development prospect: Due to the increase of bandwidth and distance, copper transmission lines will reach the limit of bandwidth and distance, and photoelectric transmission can meet the needs of bandwidth and distance increase. Optoelectronic backplane is mainly used for communication and data exchange, and will be applied to workstations and servers in the future. According to the forecast, by 2010, the global output value of photovoltaic backplane will reach 200 million USD, with an annual increase of about 14%.
Third, the development prospect of rigid-flexible composite board is very promising.
In the past, flexible FPC was called a mess. It was first called flexible board, and later called flexible board, flexible printed circuit board, etc.
Rigid-flexible printed circuit board refers to a printed circuit board containing one or more rigid areas and one or more flexible areas, which is composed of rigid and flexible boards laminated together in an orderly manner and electrically connected by metallized holes. Rigid printed boards can not only provide the supporting function of rigid printed boards, but also have the flexibility of flexible boards, which can meet the requirements of three-dimensional assembly. In recent years, the demand is increasing. The traditional design idea of rigid-flexible plate is to save space, facilitate assembly and improve reliability. The new rigid-flexible board, which combines traditional rigid-flexible board design with micro blind hole technology, provides a new solution for interconnection. Its advantages are: it is suitable for folding mechanisms, such as flip phones, cameras and notebook computers; Improve the reliability of products; The traditional assembly method is applied, but the assembly can be simplified and suitable for 3D assembly; Combined with micro-via technology, it provides better design convenience and uses smaller components; Use lighter materials instead of traditional FR-4.
The rigid-flexible board used in mobile phones is usually formed by connecting two layers of flexible board and hard board.
Development prospect: Rigid-flex board is a kind of PCB with a very rapid growth in recent years. It is widely used in computers, aerospace, military electronic equipment, mobile phones, digital cameras, communication equipment, analytical instruments, etc. It is predicted that the average annual growth rate from 2005 to 2010 will exceed 20% in terms of output value and 37% in terms of area, which greatly exceeds the growth rate of ordinary PCB. Up to now, there are few manufacturers that can produce rigid flexible board, and almost no manufacturers have the experience of mass production, so its development prospect is very promising.
Fourth, high multilayer boards bring opportunities to Chinese industry.
Multilayer board refers to PCB board with independent wiring layers greater than two layers. Generally, multiple double panels are laminated, and each layer of board is laminated into a whole board by an insulating layer. Multilayer boards generally refer to multilayer boards with more than 10 layers, which are mainly used in switches, routers, servers and large computers. Some supercomputers use more than 40 layers.
Development prospect: Ordinary multilayer board is a mature product, and its future growth will be relatively stable; However, the high technical content of high multilayer boards, together with the fact that countries such as Europe and America basically give up the conventional PCB production, bring some opportunities to the Chinese industry. It is predicted that the annual growth of high multilayer board (backplane) will be about 13% in the future.
Fifth, 3G boards improve the technical level of PCB products.
Printed boards suitable for the third generation mobile communication products (3G). Generally, 3G board refers to 3G mobile phone board, which is a high-end printed circuit board. It is manufactured by advanced two-step lamination process, and its circuit grade is 3mil(75μm). The technologies involved include a series of cutting-edge technologies of printed circuit boards such as electroplating hole filling, hole overlapping, and rigid-flexible integration. Compared with the existing products, 3G technology is obviously improved.
Development prospect: 3G is the next generation mobile communication technology, which has been applied in developed countries such as Europe, America, Japan and so on. 3G will eventually replace the existing 2G and 2.5G communications. By the end of 2005, the number of 3G users in the world has increased, and the total number has reached 100 million. In 2005, a total of 100 million 3G mobile phones of various standards were sold, and the future development will still maintain a growth rate of more than 20%. The matching printed board, namely 3G board, keeps the same growth rate. 3G board is an upgrade of existing products, which makes the overall level of PCB industry step into a higher level.
VI. HDI boards will grow rapidly in the future.
HDI is the abbreviation of HighDensityInterconnect, which is a kind of (technology) for producing printed boards. At present, it is widely used in mobile phones, digital cameras, MP3, MP4, etc. Generally, it is manufactured by Build-up method. The more times of build-up, the higher the technical grade of the boards. Ordinary HDI boards are basically laminated once, while high-order HDI adopts two or more lamination technologies, and advanced PCB technologies such as hole stacking, electroplating hole filling, laser direct drilling, etc. High-level HDI boards are mainly used in 3G mobile phones, advanced digital cameras, IC boards, etc.
Development prospect: According to the application of high-grade HDI board –3G board or IC carrier board, its future growth is very rapid: the growth of 3G mobile phones in the world will exceed 30% in the next few years, and China will issue 3G licenses soon; Prismark, the consulting organization of IC board industry, predicts that the predicted growth rate of China from 2005 to 2010 will be 80%, which represents the technical development direction of PCB.
The development is really fast, but the mistakes we will encounter in PCB design are as follows:
1.) Landing mode
Although most PCB design software contains GE component libraries, their related schematic symbols and landing patterns, some circuit boards will require designers to draw them manually. If the error is less than half a millimeter, engineers must be very strict to ensure proper spacing between pads. Mistakes made in this production stage will make welding difficult or impossible. The necessary rework will lead to costly delays.
2.) Use blind holes/buried holes
Nowadays, in the market of IoT-used devices, smaller and smaller products continue to exert the greatest influence. When smaller devices need smaller PCBs, many engineers choose to use blind holes and buried vias to reduce the footprint of circuit boards to connect the internal and external layers. Although the through-holes can effectively reduce the area of PCB, they can reduce the wiring space, and with the increase of the added number, they may become complicated, thus making some boards expensive and impossible to manufacture.
3.) Route width
In order to make the circuit board small and compact, the engineer’s goal is to make the traces as narrow as possible. There are many variables involved in determining the PCB trace width, which makes it difficult, so it is necessary to fully understand how many mA will be needed. In most cases, the minimum width requirement is not enough. We suggest using a width calculator to determine the appropriate thickness and ensure the design accuracy.
Opportunity is also a challenge. We should take my opportunity and avoid mistakes.