Green color is welding resistance ink, the main components are resin, talc and pigment, the current market is more competitive mainly Japan taiyo, Taiwan South Asia resin, Taiwan Changxing Chemical industry, Taiwan Yongshengtai ink, the price is generally 60~120 yuan/kg; Of course there are other colors, such as red, black and so on. Green is widely used.
On this question (why is the circuit board mostly green?) There are several ways to say:
Point of view 1, Generally speaking, the whole electronic board level products have to go through the process of board making and Posting. In the process of board making, there are several processes to go through the yellow light room. The visual effect of green in the yellow light room is better, but this is not the main.
During SMT welding, it is necessary to go through tinning, Posting and AOI verification. These processes should be calibrated by optical positioning. Green background color has better recognition effect on the instrument.
Opinion 2, the common red, yellow, green, blue and black, due to the problem of the process, a lot of line inspection or rely on workers to see with the eyes (of course, most of the flying needle test now). Keep looking at the board with bright eyes, which is a very tiring job oh, green relatively does not hurt the eyes, so most use green.
Blue and black, because they are mixed with cobalt and carbon respectively, have certain electrical conductivity, so there is a risk of short circuit. Green PCB is more environmentally friendly, will not release toxic gas when used in high temperature environment.
Around 2007, people began to pay attention to the color of PCB board, mainly because the board type of Asus, Microstar, these big factories have adopted black PCB board color design, so people gradually believe that the PCB color is black. Since then, more and more manufacturers have begun to use black PCB coating - can be said to be an inexplicable reason for such an inexplicable phenomenon. No one has ever said that if PCB color is black, the quality of the motherboard must be good. This is the product misdirection caused by using black to identify product positioning. Indeed, black PCB is able to show its own technical strength, because black PCB is not easy to see the line, so whether the design or after-sales will suffer from the cost pressure, and the technical strength of the board card manufacturers using black PCB tone is not because black can improve the performance of the motherboard, From the point of view of rational analysis also know that color alone can not improve the performance of the board.
Although domestic EDA has made progress, but as mentioned at the beginning of this article, the gap between us and foreign enterprises is still quite obvious. It is mainly manifested in the following aspects:
Products are not complete, especially in the digital circuit, our entire domestic EDA industry in this field is obvious shortcomings.
At Huada Jiutian, for example, only about a third of the product has been made and another two-thirds needs to be filled, according to people familiar with the matter. And an important reason for this situation is that there is not enough manpower to support the research and development. In the past discussion on EDA development in China, the industry, academia and research circles have said that if China wants to make a complete set of EDA tools, it cannot be done by a single domestic manufacturer in a day, but needs diversified cooperation.
* two, the lack of combination with technology;
In the modern integrated circuit industry, the docking bridge of chip design and manufacturing is very important, because only by dealing with this part well, can the chip be best manufactured. EDA just plays such a role, but when we are docking, there are two difficult gaps:
On the one hand, domestic EDA manufacturers have fewer opportunities to contact with the process, limiting our improvement.
It is understood that the most advanced wafer manufacturers, such as Taiwan semiconductor manufacturing Co., LTD., and Samsung Co., LTD., will not cooperate with domestic EDA manufacturers when developing new processes, which makes it impossible for us to obtain relevant support from foreign manufacturers. Of course, in my opinion, this is understandable. After all, the manufacturer has no obligation to take such risks.
Even though domestic EDA vendors have made progress in some aspects, wafers like Taiwan Semiconductor Manufacturing Co., LTD. (TSMC) will introduce Cadence and Synopsys early in the development of next-generation processes, rather than domestic EDA vendors. When the former collaborates with new chipmakers on new processes, Will * * go up another floor. Their strong strengthening, further widening the gap with domestic EDA.
People familiar with the matter said that even if the domestic EDA industry will cooperate with a manufacturer such as Taiwan Semiconductor Manufacturing in the process, it will not be introduced early, but later in the process development, and these cooperation is only part of the process, which makes the domestic EDA industry does not have access to the first part of the process.
On the other hand, our deficiency in PDK has also caused some adverse effects on the development of domestic EDA.
PDK is the abbreviation of Process Design Kit, Chinese translation is integrated circuit process design package. This package provided by the Fab includes SPICE (Simulation Program with Emphasis) parameters for process circuit simulation, hierarchy definitions for layout Design, Design Rules, transistors, resistors, capacitors and through-holes (VIA), The layout of the basic structure such as PAD, design rule check (DRC), parameter extraction (EXT) and layout circuit control (LVS) associated with the design tool are the key to the successful production of the designed chip in the wafer factory. This is the communication IC design company, OEM and EDA manufacturers bridge.