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Set micro network news, a few days ago, the listed company Fuman micro in the investor interactive platform replied to the question said that the company's 5G RADIO frequency chip has begun to supply in batches, the main customers include domestic mainstream mobile phones and ODM manufacturers, its 5G RADIO frequency chip (including filter) is completely based on independent development, with complete independent intellectual property rights, the company particularly emphasized that its filter positioning in the high-end, the module filter can support the 5G NR band, and the company has been committed to new product research and development, It also strives to fulfill its responsibilities for the replacement of domestic chips.
As soon as the news came out, the maximum increase in Fumanwei in 5 trading days has reached about 30%, which is unusually "eye-catching" under the background of the recent market trend.
The strong performance of Fumanwei stems from the urgent expectations of the capital market and even the general public for the domestic replacement of 5G RF chips.
BAW Filter "Front Breakout"
In addition to Fumanwei, this month's CSRC approved the IPO registration of the Science and Technology Innovation Board, Weijie Chuangxin, has also cut into the mobile phone 5G RF chip market, and has realized the batch supply to mainstream mobile phones and ODM manufacturers, together with Huizhiwei and other enterprises that have entered the listing counseling stage, the breakthrough of domestic 5G RF chips in technology, business and capital markets seems to have been called.
The 5G RF chip unties the noose of the "card neck", which is inseparable from the breakthrough of its core component - the filter.
Filter is one of the core components of the 5G RF front end, from the value chain is not difficult to see this, according to statistics, in the current global RF device market of about $15 billion, filters occupy a volume of $8.1 billion.
At present, the high-end filter can be divided into surface acoustic wave (SAW) and body wave (BAW) two technical routes, SAW filter market is mainly ruled by Japan's Murata, BAW filter market by Broadcom, Skyworks, Qorvo, Qualcomm and other American companies monopolized, Chinese companies accounted for negligible.
The above filter industry pattern, in addition to the first-mover advantage of European and American enterprises to construct patents and business barriers and other reasons, to a large extent also stems from the filter microelectromechanical devices in the structural design, process parameters, substrate / thin film materials and other aspects of the technical barriers, the latecomers need to break through the wide slot sacrificial layer material planarization, ultra-thin sheet thinning polishing, high precision / high orientation and high uniformity piezoelectric film preparation and other MEMS special manufacturing technology, master the piezoelectric film film structure, thickness and stress, Doped elements and proportions and a series of proprietary process parameters, otherwise it is difficult to achieve large-scale mass production, or product batch consistency is difficult to achieve standards.
It should be emphasized that because the BAW filter has the advantages of high frequency bandwidth, small insertion loss, large out-of-band attenuation, etc., and is not sensitive to temperature changes, it has obvious advantages in 5G high-frequency band applications, and the domestic replacement of 5G RF chips, BAW filters have naturally become the "main battlefield" for breakthroughs.
Wuhan Minsheng, a MEMS company that has allegedly received 13 million research and development funding from H-led electronics giant, is a typical sample of this breakout:
In terms of process technology, in August 2021, Wuhan Minsheng's world's largest MEMS foundry Silex parent company - Beijing Sai Microelectronics Co., Ltd. reached a cooperation agreement, in the latter Beijing Fab3 factory to jointly invest in process equipment, division of labor cooperation, the establishment of the domestic leading 8-inch RF filter production line, and it is expected that by the end of 2022, the Beijing production line will achieve a line and reach about 2,000 pieces / month production capacity.
In terms of device design, according to the information obtained by the agency's research, Minsheng has mastered more than 100 technical patents, which can bypass the broadcom patent barriers, and in the mainstream configuration of the 5G band BAW - FBAR, "the technology is comparable to AVAGO (Broadcom)".
In terms of material innovation, Wuhan Minsheng recently announced that it has taken the lead in opening up the whole process of high-scandium-doped aluminum nitride in China, which can be called the biggest difficulty of breaking through the BAW filter.
The core material relied on by the high-frequency BAW filter is the aluminum nitride film doped with the rare earth element scandium, that is, the aluminum scandium nitrogen (AlScN) material, but the low-scandium doping related technology is monopolized by American companies, coupled with its application to high-performance military filters, so the United States has implemented a blockade on the export of the material for more than a decade, and the domestic development is very lagging behind, to some extent, it can be said that the aluminum nitride material system is the most critical part of the United States to be able to "card neck" on high-end 5G RF chips.
In fact, the breakthrough of Minsheng is not alone, according to the micro-network understanding, with the joint efforts of various domestic industry-university-research institutions, the mainland aluminum nitride material system has now made an overall breakthrough.
Earlier in 2021, the start-up company Aoxiang Optoelectronics has launched its own research and development of sapphire-based aluminum scandium nitrogen film template products to the market, and the company's founder Wu Liang said that it is cooperating with several leading downstream enterprises in China to gradually achieve high-performance 5G FBAR/BAW/SAW filter manufacturing.
At a MEMS innovation development and application seminar held recently, Wu Liang further shared the company's breakthrough in the preparation of aluminum nitride and aluminum scandium nitrogen (AlScN) materials, according to Wu Liang, his company has successfully developed the world's largest diameter 60mm aluminum nitride single wafer and achieved small batch production, while realizing the large-scale preparation of 2-inch / 4-inch / 6-inch aluminum nitride / aluminum scandium nitrogen film template, the company's aluminum nitride wafer after the localization, It has greatly reduced the research and development costs of domestic downstream filter devices and solution providers.
The aluminum and scandium nitrogen materials doped with rare earth element scandium can greatly improve the piezoelectric properties such as aluminum nitride quality factors and coupling factors, but the deposition doping process of scandium, especially the doping process of high scandium concentration, is still immature, and after the content of scandium is improved, the phase change from fiber zinc ore structure to cubic crystal salt and stone structure is easy to occur during the growth process of thin film, and the stability of the thin film crystal phase is difficult to control.
In this field, Aozhi has been at the forefront of the world, Wu Liang said, Qualcomm and German universities to cooperate in the trial production of aluminum scandium nitrogen films, the material performance is not as good as the sapphire-based and silicon-based aluminum-scandium nitrogen products that Autuo has released.
In addition to thin films, Wu Liang also mentioned that the company's aluminum nitride substrate materials are currently opening up the 4-inch wafer preparation process, once realized, it will mean that it can use the greater supply chain ecology to push the cost of aluminum nitride materials to the same level as silicon carbide, thereby cutting into the booming power semiconductor market and further tapping the potential of aluminum nitride, a new compound known as super semiconductor and fourth-generation semiconductor.
However, Wu Liang also admitted that although the preparation process has made a breakthrough, but the simulation and design tools, production tools and equipment, still rely on overseas suppliers to a considerable extent, the domestic industrial ecology is still thin, domestic substitution has a long way to go, for example, the current alumina piezoelectric film thin film deposition is an important link in the manufacturing process of MEMS devices, and thin film deposition equipment has a high technical threshold, the current thin film deposition equipment is still based on overseas imported equipment, such as aluminum nitride piezoelectric film deposition and film repair equipment, It is dominated by amS corporation in the United States.
The domestic substitution of more upstream equipment and tools is undoubtedly a difficult task for domestic manufacturers in the next stage.
SAW Filter "Raiders"
Saw filters, which seem to have been stripped of their light by BAW in the 5G era, still occupy more than half of the market for filter shipments and value.
Saw filters with lower frequencies are not as technically difficult as the BAW route at first glance, but because the relevant frequency bands are more crowded, there are higher requirements for system-level integrated design capabilities, and at the same time, the industry giant Murata, in this field, patent barriers in this field, are far more stringent under the oligopolistic pattern.
At present, most of the domestic enterprises that have entered the filter business have chosen the SAW field as a breakthrough to play the value of domestic substitution in low-end products, but the natural disadvantages of the pricing ability of enterprises in the low-end market have brought constraints to the upward breakthrough of related enterprises.
On the one hand, the price war of low-end SAW filters makes it difficult for enterprises to improve gross profits and lengthen the payback period of early investment; on the other hand, the upstream core materials - lithium tantalate (LT), lithium niobate (LN) crystal piezoelectric substrates, but firmly held in the hands of Japanese companies such as Sumitomo Chemical and Shin-Etsu Chemical, the profits that Chinese filter manufacturers have worked hard to make, but they flow back to Japanese companies through high-priced substrate substrates.
Although existing institutes and enterprises in China have initially mastered high-end technologies such as blackening and reduction of LNLT crystals, the quality, output and cost are still unable to compete with Japanese companies, and are often only digested within IDM enterprises, and it is difficult to form an effective lever to leverage the upstream industrial pattern.
In the face of the 5G and even 6G trend, as well as low-end product competition from Chinese companies, the choice of industry leader Murata is to exert efforts on high-end SAW filter technology.
Traditional SAW filters are difficult to achieve frequencies above 1.8GHz, but Murata's IHP-SAW technology can achieve frequency performance of 2.5-3GHz and even higher.
At present, there are also domestic institutions that are following up on Murata's actions to tap the potential of surface wave SAW technical routes from different entry points.
(Layout features of FBAR irregular polygons to ensure that the number of shear wave reflections is reduced and the resonator quality factor is improved)
Gao Yang's team of the Microsystem Center of Southwest University of Science and Technology, after combing the technical evolution characteristics of Murata IHP-SAW, boldly adopted the latest achievements of the new conductive wave layer piezoelectric material system based on aluminum nitride and the heterogeneous acoustic layer (HAL) structure substrate, and the HAL structure resonator tried to be produced by aluminum scandium nitrogen material has been in line with the data disclosed by Murata without optimization.
Gao Yang also further looked forward to the IHP-SAW-driven HAL structure trend and aluminum nitride material system, or will shake the monopoly position of Xinyue Chemical and other manufacturers in the field of single crystal substrates such as lithium tantalate and lithium niobate required by traditional SAW, and HAL structural devices based on aluminum nitride wafers will profoundly change the SAW industry ecology.
It is worth mentioning that the Gaoyang team also jointly established an intelligent microsystem joint laboratory with Onry Micro (Han Tianxia) to open up a channel for the rapid industrialization of research results, which is also an active player in the domestic 5G RF chip track, and has been invested by Huawei and Xiaomi, and its products have been applied on the Honor 50 mobile phone.
The team of Ou Xin researchers at the Shanghai Institute of Microsystems of the Chinese Academy of Sciences used the "universal ion knife" stripping and bonding transfer technology to break through the problems of lattice mismatch, peel off the sub-micron thickness of single crystal lithium niobate wafer and transfer it to a high-sound, high-conductive silicon carbide (SiC) wafer, and prepared a 4-inch Ln/SiC piezoelectric heterogeneous substrate for the first time, which can achieve more effective sound wave energy and electric field energy constraint, improve device heat dissipation, and reduce device thermal expansion. This significantly improves rfosonic device performance and design freedom. The high-frequency device prepared based on this substrate breaks through the frequency limit of traditional SAW devices. It is expected to be applied to the 5G N77 and N79 bands.
On the SAW battlefield, the domestic industry-university-research institution "Strange Soldier" has explored the dawn of a breakthrough to 5G and even 6G.
epilogue
From Huawei's flagship mobile phone P50, which was listed last year, to this year's P50 Pocket, the lack of 5G network access capabilities is undoubtedly the most obvious flaw in consumer perception.
When Qualcomm obtained permission to send a "special version" of the Snapdragon 888 4G chip to Huawei last year, the Financial Times quoted industry insiders as saying that ensuring that the products provided are not implicated in Huawei's 5G business is the premise of the US commercial cooperation.
Because of this, the mobile phone 5G RF front-end module chip monopolized by overseas companies has become one of the main technical bottlenecks in the return of huawei's mobile phone business king.
Who can solve the domestic substitution of 5G RF chips?
Although the answer to this question has not yet been revealed, more and more and more powerful solvers have emerged.
The breakout of the 5G filter is only a matter of time. (Proofreader/Rakukawa)