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Silicon wafer cutting technology turns the annual golden age of the golden age

At present, the cost of silicon wafer and silicon is about 40% of the photovoltaic module, which is accompanied by the slope of the photovoltaic subsidy, the pressure of the silicon chip end is huge, and the vajra line section becomes the effective reduction tool.

The growth of the pv industry is positively correlated with the expansion of the market size. The improvement of technology is the most effective way for pv to reduce the price of pv. In order to promote the development of single and polycrystalline silicon products in a balanced way, and accelerate the process of photovoltaic (pv) online, the technology of wire cutting is highly anticipated.

Reducing the efficiency of the photovoltaic industry is the driving force. In 2009, it began its golden age in 2014, with the technology of "king kong" cutting silicon wafers. The single crystal leading enterprises, such as longji and zhonghuan, have been the first to popularize the technology. In the first half of this year, with poly (xin black silicon, polycrystalline giant announced first production line put into production and then transfers of black silicon technology, has the agency predicted, king kong wire-cutting technology this year is expected to be in domestic popularization, the formation of a new "growth pole" photovoltaic industry.

Solar pv cutting technology transition year

"Two or three years ago, it was unattainable to mention the king kong line. But this year it can be thought of as the turning point of the traditional mortar cutting to the cutting of the king kong line. Dr. Song denyuan, director of the national key laboratory of photovoltaic materials and technology, said the turnaround was faster than many had expected. "The technology of the silicon wafer cutting and battery whole industry chain can greatly reduce the cost of photovoltaic power generation and the efficiency of solar cells, and become a hot spot in the industry." He said.

Due to the pressure of traditional mortar cutting technology in terms of cost, environmental protection and quality, it has been developed rapidly in China in recent years. It has advantages such as low silicon consumption per unit capacity, high cutting efficiency, low cost of auxiliary materials and cutting thin silicon chip, etc., which is firstly applied in the field of monocrystalline silicon. At present, in monocrystalline domain, vajra technology has basically replaced the traditional slurry cutting technology.

However, it has not been widely promoted, and also resulted in the change of single lattice bureau - nearly 10% of the multi-crystal market share is occupied by single crystal. In nearly a decade, microtek silicon photovoltaic application market accounts for about 90% of the share, polycrystalline silicon photovoltaic market always occupy the mainstream status, to 2016, polysilicon market share of about 70%, single crystal is about 20%.

This gap can be seen from a number of comparative data: in 2014, the proportion of macadamic cutting polycrystalline and single crystal was significantly different, at 16% and 75% respectively. Nearly two years for closing the gap, but still difference: although kong wire-cutting polycrystalline silicon slice of the proportion of using direct jumped from 25% in 2016 to 60% in 2017, but at the moment, single crystal king kong line using rate has reached 100%.

It is in the industrial expansion air outlet "2017 is the first year of the multichip industry, and its momentum is hard to imagine." Yang Lingmei chang new materials co., LTD., chairman wu ying think, in addition to the whole pv line comprehensive into an era, king kong line section, this trend also give king kong line manufacturing, slicing machine manufacturing and other related enterprises with great opportunities. And Yang ling mei chang herself is a good example. The company started production in January last year with a profit of 236 million yuan and a profit of 95 million yuan. By the end of 2016, the world's leading supplier of the vajra line has grown.

At present, China is the world's largest producer and largest photovoltaic market. According to industry experience, each slice of silicon (about 4W) consumes about 1.5 meters of the plating. According to the data of China's photovoltaic industry, the global production capacity of polysilicon reached 490,000 tons in 2016, producing about 400,000 tons, while China's polycrystalline silicon produced 19.4 tons, accounting for 50% of the world's production of polycrystalline silicon. In terms of silicon, the global output reached 74.8GW in 2016, including the 17.3GW in the 2016 silicon wafer production, leading the rest of the world. In the first half of this year, the production of polysilicon, silicon wafers and batteries in China was 115,000, 36GW and 32GW respectively. For the foreseeable future, the main demand for the diamond line will remain concentrated in China.

According to EnergyTrend, the market share of single crystal market is expected to be 35%, 50% and 70% in 2017 and 2019. Assuming that the single crystal diamond line is basically realized, the penetration rate of the multi-crystal diamond line is 10%, 30% and 50%, while the global photovoltaic demand is 14.2 billion meters, 25.2 billion meters and 33.4 billion meters respectively. At the same time, the demand for sapphire is superimposed, and it is estimated that the total demand will reach 15 billion meters, 26.100 million meters and 34.5 billion meters between 2017 and 2019.

According to incomplete statistics, there are now nearly 100 enterprises engaged in the production of the king kong line, including nearly 10 listed enterprises, including two Japanese listed companies. Even so, the market for the entire king kong line is still in short supply, with companies saying "there is a silver line", and that the king kong line and its related industries are in the process of expanding production.

Promote the rapid development of pv "The king kong line slicing equipment is still mainly produced abroad, but the domestic slicing technology, especially the diamond cutting polysilicon slice, is the leading position in the world. Because bolt risks and velvet difficult, a few years ago king kong line polysilicon slice always didn't get a wide range of promotion in our country, but has never stopped, industry to explore the footsteps of polycrystalline silicon slice manufacturer's equipment upgrading and mature technology takes time, finally achieve a breakthrough this year." Dr. Pu tian, director of technology for the company's energy holdings, told reporters.

Through line of king kong industry breakthrough in preparation and application technology of optimization can effectively reduce the gold wire cutting break risk of polysilicon, manufacturing technology, black velvet additive silicon technology or pretreatment technology can effectively solve the velvet difficult problem. According to the reporter's understanding, current China's dry method black silicon and wet method black silicon two kinds of technical route, all have achieved the quantitative production.

Ja solar holdings co., LTD., vice President, xin-ming huang, "says Dr. Diamond wire cutting polycrystalline is inevitable trend, it is a significant decline in the cost of will inevitably drive technology innovation, promote product optimization, to maintain the healthy and continuous development of enterprise and industry. "Based on the superimposed integration of black silicon and PERC, we can achieve more than 20% of the scale production of the conversion efficiency based on the low cost of the vajir-cut silicon wafers," he said.

According to jin shanming, vice President of baoli xixin section, the multi-crystal will reach 285W and the black silicon superposition PERC is the first choice. "In the process of promoting the technology, the demand for poly's huge amount has directly contributed to the completion of the listing of the two industrial chains," he said.

Kong line polysilicon slice and the popularity of black silicon technology will widen again in polycrystalline and single crystal silicon on the cost difference, and the black silicon and the PERC, SE and MWT combination can further enhance the production efficiency of the polycrystalline cells, enhance the competitiveness of the polycrystalline silicon solar cell line. It is expected that the photovoltaic market will provide a good market opportunity for the cutting and the efficiency of the battery and components cost reduction and efficiency improvement.

Seeger, Germany: significantly improved tool life

At Seeger Prazisionsdrehteile, 24 hours of production is required every day. On public holidays such as Christmas and Easter, if knives are allowed, they are still produced. During this period, a thousand parts can be produced at a time by constantly changing the blades. For the chief executive of Seeger Prazisionsdrehteile, the chief executive of Seeger Prazisionsdrehteile, the right tool can play a decisive role when Wilhelm Seeger is used. "The less the knife problem, the less wear, the longer the service life, the better the production run. Even if grooved blades can make up to 40, 000 parts, this happens even more often." "Wilhelm Seeger says. Enter the production workshop in Salem- Neufrach, which was built by these lathe parts experts in 2013, and you can see 90 horizontal lathes and various fixed machine tools. Each year, it produces stainless steel, steel, copper and aluminum parts, totaling about 50 million pieces. It can produce rods between 3 and 42 mm in diameter. For multi-purpose vehicles, automobiles, hydraulic industry and medical fields, the smallest parts are produced in batches of 50 ~ 5 million. Wi lhelm Seeger points out that internal machining of electrical components must be highly accurate. The specified tolerance is as high as 0.02 mm. Use the AMS microsystem of Arno-Werkzeuge to make parts. AMS system is specially designed for drilling more than 0.7 mm, and provides high strength and high machining safety in a wide range of machining possibilities. The uniform milling of the top of the blade and the fixed pin in the handle can ensure the repeat accuracy of the center. Precision cutter manufacturers not only grind cutting edges, but also grind the entire blade. In addition to standard procedures, special tools can be provided. The goal is to leverage long-term customer relationships to find quick solutions to new challenges.

Continuous production, not peak production The cooperation began with a thin, extremely long and ultimately loaded part of the ABS system for the automotive industry. Produce 3 million 1.4105 stainless steel parts at one time. In the past production of this kind of lathe parts, or in the old production workshop, there will be accidental damage to the tool from time to time. For surface quality and dimensional accuracy, AMS system testing is more than the previous results. Using the new blade, the Arno Werkzeuge, based on previous cutting parameters, has been successful and currently produces 8000 pieces, which used to produce only 2,000 units. Life expectancy increased by 400%. For Wilhelm Seeger, the longer service life, only the higher priority goal of processing security, makes sense. Wilhelm Seeger: "the secret to efficient mass production is not the strong tool stress and the short-term peak, but the long-term results." This boundary cutting speed is indeed a problem given the bulk fluctuation of the working materials. During the smooth operation, the process is interrupted so that the processing safety is not guaranteed.

Improved service life After replacing the tested tool, carefully check the production of other parts. "Arno Werkzeuge can actually extend the average life span of a small range of knives by 50 per cent compared to competing products," Wilhelm Seeger said. These results prove strongly that the use of this equipment can realize the cost savings of different tools. Even after replacement, Wilhelm Seeger and Arno Werkzeuge are still making further optimizations. At present, they are fine-tuning the friendly performance of the operator, modifying the tool holder to improve the replacement speed of the cutting blade. One of Arno's field workers explained: "this user-centered clamping solution is tested directly in practice to meet customer needs. This is a service that we are very happy to provide for Seeger." Arno field staff are familiar with the problem of horizontal lathe. "Employees at Arno Werkzeuge used every opportunity to learn about the situation," added Wi lhelm Seeger. What are the actual production conditions? How much space is really used for tool replacement? Are there any challenges that need to be addressed?

For such machine tools, simple and quick and low-cost replacement of knives is the most important. Arno Werkzeuge first USES a dedicated tool and then turns it into a standard cutter to meet customer needs. Special space conditions of horizontal lathe are considered when cutting tool replacement. For the machine tool of fixed knife head, the knife tower can move to a comfortable change position, and compared with it, replace the cutter on the horizontal lathe, almost blindly execute. A relatively large number of errors may occur in this step. Because the scope of the machine space is very limited, it can only replace the cutting blade with the feeling of feeling. Through direct contact with machine tools, Arno design engineers can better assess which areas are feasible and which are tricky. How accurate is the internal cooling channel during replacement? How do you match exactly?

The first discussion and the first draft were only a few weeks apart. According to experience, follow-up will generally be corrected once or twice. The accumulated experience will be further developed and can be used to replace the cutter again. The goal is to achieve optimal service life and functionality.

Quality, not quantity The situation faced by universalworkers also prompted the turning experts to take measures. A few years ago, almost all of the machine tools were skilled workers, and now, because of limited training, companies are forced to use workers with little knowledge of machine tools to work. Arno Werkzeuge provides assistance by working with customers to make the tools as easy as possible for operators to operate. How can we simplify the process of using tools for workers? Shorter tool replacement time, and guaranteed center high repeatability, play a major role in improving the availability of machine tools and improving product quality. Seeger proposed expanding the variety of tools available for AMS systems to be applied to different processing stages. But other systems (such as the SIM program, which aimed at the internal processing of the aperture of 6.7 mm) have also produced good results. "We are more willing to strengthen our business ties with small suppliers. Technical support, smooth cooperation - what else do we want?"

Carbide die

Carbide die life of more than ten times that of steel or even dozens of times, hard alloy moulds only high hardness, high strength, corrosion resistance, high temperature resistant and low expansion coefficient, are generally use cobalt tungsten carbide.

Brand and production technology

As the market standard material YG3, YG6, YG6X YG8. YG15, YG20, YG20C, YG25 and HU20 HU222, HWN1 (non-magnetic alloy mold), etc., using native carbide material, low pressure sintering and other special craft, toughness is better than the regular production, life will also improve 3-5 times.

Should have a field

Hard alloy dies often: cold upsetting die, cold die, drawing die, hexagon mould, screw die, etc.


Hard alloy dies can be divided into four categories according to their use:

The first type is hard alloy wire drawing die, which makes up the majority of hard alloy mould. At present the main brand of wire drawing die YG8, YG6, YG3, followed by the YG15, YG6X, YG3X, developed some new brands, such as new brand YL, used in high speed wire drawing and wire drawing die brand CS05 imported from abroad (YLO. 5), c20 (YL20), CG40 (YL30); K10/19 dated, ZK20 / ZK30.

The second type of mould is cold upsetting die, shaping mould, which has YC20C, y20, YG15, CT35 and YJT30 and MO15. The third type of mould is the non-magnetic alloy module used for the production of magnetic materials, such as YSN (20, 25, 30, 35, 40) of the YSN series and the non-magnetic model of the steel junction TMF. The fourth type is thermal mode, which has no standard plate number, and the market needs to increase.

Tungsten provides a minimum resistance path for nano-interconnection

As microchips become smaller and smaller, the size of the copper interconnection shrinks, leading to a faster increase in resistivity at the nanoscale. Solving this coming technical bottleneck is a major problem in the semiconductor industry.

It is very promising to solve this problem by changing the crystal orientation of the interconnect material to reduce the resistivity. Two researchers from rensselaer polytechnic institute have carried out electron transport measurements in the epitaxial layer of tungsten (W), a potential solution. They carried out the primary principle simulation and found the orientation dependence effect. And they found that the anisotropic effect of resistivity is the most obvious between the layers of lattice structures with two specific orientation, namely W (001) and W (110). The work was also published this week in the journal of applied physics.

Author peng-yuan zheng, points out that in 2013 and 2015, the international semiconductor technology roadmap (ITRS) have called for the new material to replace copper as the interconnect material, to reduce the restrictions on the size scale resistance increases, and minimize the power dissipation and signal delay. In their study, zheng he and co-author Daniel Gall chose tungsten (i.e., tungsten replacement copper) because of its asymmetric Fermi surface (i.e., its electron energy structure). This makes it a good candidate to demonstrate the effect of anisotropic resistivity on a small scale. Gall said: "the big block material is fully isotropic, so its resistivity in all directions are the same, but if we have thin film material, so the resistivity will happen very big change."

In order to test the direction of the best, the researchers on substrate epitaxial growth W (001) and W (110) membrane, and at 77 K (about 196 degrees Celsius), room temperature or under 295 K immersed in liquid nitrogen for both the resistivity measurement. "The difference in resistivity between 001 and 110 orientation is roughly twice that," Gall said. "but they found a smaller resistivity in the W (011) layer."

Although the measurement of anisotropic resistance effect is consistent with the calculated value, but in the experiment of thin film, the average effective degrees of freedom (electronic can move before scattering to the boundary of the average distance) is more than the theoretical value of the massive tungsten. Gall said: "electronic through the wires on the diagonal, hit a surface, spread out, and then hit will continue to move until something else, these things may be the other side of the wire or the lattice vibrations. But this model is wrong for small wires." The experimenters thought this could be explained by the quantum mechanical process of producing electrons on these limited scales. Electronic can simultaneously with the decrease of the thickness, both sides of the contact wire or experience increases the electron - phonon coupling (lattice vibration), and this is likely to affect to look for another metal instead of copper interconnect.

"Rhodium, iridium, nickel's conductivity may be smaller than predicted," says Mr Cheng. Such a result will become increasingly important because the quantum mechanical scale is becoming more and more common to the need for interconnection. The team is continuing to explore the anisotropy dimensions of other metals, and these metals have to have aspheric surface, such as molybdenum. They found that the orientation of the surface relative to the orientation and direction of transmission was critical, as it determined the actual increase in the decrease of the hour resistivity.