Traditional memory technology makes domesticZiguang Group,Hefei Changxin,Fujian JinhuaThe three parties are competing to invest, and the domestic storage chip to replace the import of the footsteps, such as the fire of the original, has been difficult to calm down.
However, another new memory technology team that has been crouching for nearly 20 years includesMRAM,PCRAMwithReRAMBenefittechnology,material,deviceThe key breakthroughs in other links are on the way to mass production, and we are at a turning point in witnessing the history of memory.
however,At this point in time, it is also the breakthrough of the domestic memory chip, “zero”, self-made, on the eve of mass production.What impact will new storage technologies have on traditional memory DRAM, 3D NAND, and SRAM? Will it form a "replace" effect?
Intel 3D XPoint turned out, industry renewed hope
New memory can be divided intoStand-alone product,as well asEmbedded in logic processIt is used to replace some of the traditional embedded flash memory eFlash technology, and in embedded technology, the trend has rapidly matured. However, for stand-alone memory, there are still performance and cost issues to be overcome.
therefore,New memory, whether it isMRAM,PCRAMwithReRAMWaitAnd won’t hit the presentThe country is in full swingDRAM,3D NANDChip industryHowever, for some application areas such as cloud computing, Internet of Things-driven edge computing, the addition of new memory technology can really make the development of the entire industry even more powerful.
Figure 3D XPoint (Source: Intel)
New memory technology has been proposed for nearly 20 years, and the road to maturity is stumbling. Until 2015, Intel's 3D XPoint technology was born, and it is considered to be similar to the structure of PCRAM. The whole new storage technology is suddenly clear, and the development in the next few years is even more powerful.
In order to add firewood to the new memory industry, the world's leading semiconductor applications have introduced two machine tools for MRAM, PCRAM and ReRAM:Endura Clover MRAM Physical Vapor Deposition (PVD) Machine,as well asEndura Impulse Physical Vapor Deposition (PVD) MachineIt has become a powerful promoter of the development of the industry.
DeepTech passes two experts with the application materials, respectivelyDr. Zhao Ganming, General Manager and Chief Technology Officer, Applied Materials China,as well asDr. Zhou Chunming, Global Product Manager, Applied Materials Metal Deposition ProductsThe dialogue, to see what changes the new memory will bring to the world, to witness the historical turning point of the storage industry.
Here, DeepTech's panoramic analysis of the key reasons for the recent rise of new types of memory, which manufacturers have begun mass production, application principles and areas, and the benefits to the industry.
Moore's Law is fading, new memory is on the battlefield
Moore's Law, which was introduced in 1965, has been written for more than 50 years. It has written countless milestones for the global electronics industry. But today, the chips designed and produced according to this law are the four most important standards for semiconductors in PPAC. Performance Performance, Area Area, Cost Cost are gradually decreasing.
Many of the chips needed for the Internet of Things and cloud computing are not available from Moore's Law. Why?
In the era of “Internet of Everything” and “Industry 4.0”, the data showed explosive growth. For example, we generate about 1GB of data per day, but when you drive a driverless car, the amount of data generated in a day can be as high as 4000 GB, which is equivalent to 4,000 times.
2019 is a crucial year, and the data generated by the machine has exceeded the data generated by humans. This is the first time in human history.It is expected that by 2022, the machine will produce data that is nine times as large as human-generated data.
The logic of future world computing is that data comes from the collection of machines, including cars, smart cities, smart homes, etc. All generated data must be transmitted and calculated from the terminal, from the edge, through the layers, and then to the cloud, to the big data. Center, then calculate, and then return to the terminal.
In this short period of time, the influx of data from the top of the world, and the constant calculation, processing, and retransmission, is very challenging chip performance, and the existing computing architecture has long been unable to meet the core needs.
In the past, the era of Moore's Law, the pursuit of transistors is getting smaller and smaller, the goal is to double the number of transistors every 18 months to two years, but as the effect of this law decreases, from 14 nm to 10 Nm nm, it may take 4 years, from 10 nm down to 7 nm, 5 nm, it takes longer, Imagine Intel 10 nm has been deferred to see one or two.
Therefore, more and more people are arguingWhether Moore's Law has reached the end of its life?
To answer this question, we can think like this. If you continue to use traditional thinking and increase the density by reducing the size of the transistor, you can't do it. However, from another perspective, there are many ways to achieve the above PPAC (power consumption, performance, area, cost).
The industry has now proposed various "tricks" to continue Moore's Law, here DeepTechFive levelsTo explore.
New architecture: Google's TPU, Nvidia's GPU, as an accelerator role to improve computing, especially in the cloud computing performance.
New structure: 2D two-dimensional to 3D three-dimensional NAND, because it is a three-dimensional structure, so you can always go up, the space up can be improved.
new material: I used to take out a periodic table of elements. The elements in semiconductors and transistors have been added a lot. For example, the copper process replaces the aluminum process, and the cobalt replaces the copper, which can significantly improve the performance of the transistor and highlight the new material. An important role in promoting PPAC.
New miniature technology: ASML Extreme UV Lithography EUV.
New packaging technologyDifferent types of different process technologies, such as 28nm or 5nm processors, memories, accelerators and other chips, are integrated through advanced packaging technologies to achieve optimal performance at the system level. For example, the packaging technologies InFO, CoWoS, and 3D ICs introduced by TSMC in recent years, as well as EMIB and Forevos launched by Intel, are all started from the latter stage and continue the life of Moore's Law.
In-Memory Computating concept fires up
In the era of big data, it highlights the importance of huge computing needs, and also drives the development of hardware and the revival of investment. For example, the above-mentioned accelerators, if we go deeper into the discussion, we should propose a concept here, that is, “Near memory calculation” (Near Memory Computing).
What is Near Memory Computing? In short, in the past we often have a concept that is “The processor is king”, think that the processor's ability is the most important, but not now.
because,Computing power is no longer determined by individual processor capabilitiesIt means that the data is transferred back and forth between the processor and the memory, and because of the bottleneck, the computing power can no longer advance.
The definition of Near Memory Computing is to use a large amount of high bandwidth and large capacity to connect memory and computing processors more closely, and to increase computing performance at the system level.
This concept is actually implemented with existing building blocks, such as DRAM, NAND, SRAM, etc. In the future, it will gradually combine with new memory MRAM, ReRAM, PCRAM to increase computing performance, and create “Memory calculation” (In-Memory Computating).
In-Memory Computating has been a very hot concept in recent years, butIt may take at least 3 to 5 years to achieve. Unlike Near Memory Computing, which puts storage and processing closer together, In-Memory Computating integrates storage and processing for computing, with no problems with transmission, latency, and performance.
Looking back 10 to 20 years, brain-like computing and quantum computing can achieve the above goals, but these technologies are too far-reaching. If you want to achieve the goal of In-Memory Computating as soon as possible, at least within 5 years, the new memory will play very much. important role.
Which semiconductor manufacturers have begun mass production of new memories
Before discussing the operation of the new memory, let's talk about which semiconductor manufacturers have mass-produced MRAM, ReRAM and other technologies.
The camp currently investing in research and development or production of new memory technologies can be divided intoThree categories.
the first sort:Logic process foundryIncluding TSMC, GlobalFoundries, SMIC, Samsung Electronics, etc., mainly embedding MRAM and ReRAM storage technologies in mainstream process technologies, which are embedded memory applications, not production of stand-alone memories.
Second class:Standalone memory manufacturerFor example, Group and Evenspin have partnered to integrate 1Gb STT-MRAM into the enterprise SSD system to act as a cache to improve SSD performance.
Third category:Research institutions, academic institutions, etc..
In addition to the 3D XPoint technology developed by Intel and Micron, the semiconductor companies that are developing MRAM, ReRAM, and PCRAM technologies include TSMC, IBM, SK Hynix, Western Digital, and GlobalFoundries.
In the technical forum, TSMC actually disclosed the MRAM and ReRAM technology processes.
TSMC's current 40nm ReRAM has the capacity to mass-produce, replacing the traditional embedded flash eFlash technology on the IoT chip, emphasizing that the stored chip can be stored for 10 years and after 10,000 times of reading and writing.
Furthermore, TSMC's 22 nm MRAM also has mass production capabilities. Unlike ReRAM technology, this MRAM technology is used in mobile devices, high-performance computing HPC, automotive electronics, etc., replacing traditional embedded flash eFlash technology. .
In terms of performance, 22 nm MRAM is three times faster than eFlash technology, and the data can be stored for 10 years and subjected to 1 million readings and readings at high temperatures.
Sung Gon Jin, head of SK Hynix Advanced Thin Film Technology, also said thatIn addition to DRAM and NAND, we are also investing in next-generation memory development to improve data center efficiency..
In addition, GlobalFoundries is also investing in MRAM, a new state of embedded memory technology. Developed in conjunction with Everspin, the company has also revealed the introduction of embedded eMRAM technology into the 22 nm FD-SOI process to produce complex automotive MCU chips. Used in advanced driver assistance systems (ADAS) systems or in other automotive systems.
Figure GlobalFoundries (Source: DeepTech)
The principle and application of new memory
MRAM is magnetic random access memoryThe architecture is that the memory cells in the transistors are interconnected at the back end, and even do not occupy the area of "silicon", which can be directly embedded into the logic circuit, so it can be made very small, one transistor and one memory cell.
Furthermore, PCRAM is a phase change random access memory, and ReRAM is called a resistive random access memory. What is more attractive than MRAM is that these two new storage technologies can implement 3D 3D architecture just like NAND.
The advantage of the 3D architecture is that it can be stacked all the time. When adding one layer, the density of the memory can be doubled. In addition, the cost can be reduced.Large capacity, low costTherefore, it is very attractive to use in cloud computing and big data centers.
It can be said that the application of the new type of memory is very wide, but if the benefits are maximized, the two applications are locked first:Internet of Things, cloud computing and big data centers.
We often talk aboutInternet of ThingsIs calledEdge terminal,Edge device.
The current edge device architecture is a logic chip plus an SRAM chip. The function of the SRAM is to calculate and then add a 3D NAND chip to store the algorithm/software/code.
The so-called "edge" is because there is no connection, no power, the power consumption problem is very important, because the power can decide how long it can take.
At this time, MRAM can replace the function of SRAM. Because SRAM is also power-consuming and even leaking when not in use, some edge devices may be on standby for 99% of the time. If you replace the SRAM with MRAM, you can improve a lot of power consumption problems.
The same is true for 3D NAND. It is actually a high-voltage device. If part of the MRAM is used instead of 3D NAND, the power consumption can be reduced.
MRAM has two major advantages.The first is that it does not consume power when it is in standby.,The second is much cheaper than flash memory.If the shortcoming is, the speed of MRAM has not yet reached the SRAM level. For example, MCUs that are widely used in the Internet of Things, etc., MRAM is very suitable for use.
Next, look at the cloud and the big data center. This field hasThree challenges.first of allInflux of massive data, come againNeed to perform fast calculations,The thirdThe key is still back to power consumption.
The current mainstream architecture is DRAM plus SSD to store data, but how do you use new memory to improve performance?
method oneIt is to replace the DRAM part, because from the power point of view, DRAM has power consumption to the problem. Furthermore, PCRAM and ReRAM can be cost-effective after they can be used as a 3D architecture.
Method TwoIs to replace the SSD part. The advantage of SSD is that it is cheaper. Thanks to the maturity of 3D NAND stacking technology, 128-layer stacks are now in mass production. The cost of 3D NAND is getting lower and lower, but the weakness is performance.
If you replace some DRAM with PCRAM and ReRAM, you can also implement 3D architecture. Secondly, performance is much better than SSD.
Source: Applied Materials
How does new memory work?
Magnetic memory is a three-layer structureThe middle is called "tunnel junction", which is magnesia, two magnetic layers on both sides, the magnetic layer can be understood as two magnets, and the two magnets have north and south poles. If the north and south poles match, the electrons are easy. By going, the resistance is a relatively low state.
Furthermore, the magnetic layers on the upper and lower sides can be turned parallel to the lower side by the current, which is a mismatch. When there is no match, the electron is difficult to pass, and it is a high resistance state.
Therefore, through low resistance and high resistance, the storage of """"""1" is actually a memory technology based on resistance change, which realizes high resistance and low resistance by magnetism.
PCRAM and ReRAM are similar in principle and are controlled by current or voltage. PCRAM is a crystal form to control low resistance and high resistance. When it is fully crystallized, it is a low-resistance state. When it is amorphous, it is a state of high resistance, thereby achieving “0” and “1”.
ReRAM is similar. The non-conducting place is a high-resistance, like the insulating material. After the power is turned on, the conductive path can be realized, showing a low-resistance state, so similar to MRAM, through the high and low resistance to achieve " And “1”.
In short, to achieve this new type of memory is to achieve the basis of these memories through material engineering, there are still some challenges to overcome.
Source: Applied Materials
Equipment technology breakthrough, the era of scale has finally arrived
For large-scale production of new types of memory, material engineering breakthroughs in equipment manufacturers are key. Application Materials For the MRAM-designed Endura Clover MRAM PVD system, multiple process steps can be performed under vacuum, implementing 10 materials of the entire MRAM, and then stacking 30 layers by layer, the core of which is Clover PVD, one The chamber can be used to achieve up to five materials and then deposit a thin film at the atomic and subatomic levels.
As mentioned before, there is a magnesium oxide layer in the middle of the MRAM. The application material indicates that the middle magnesium oxide layer is very important, which will affect the performance of the entire MRAM Device. The application materials are built using unique techniques to make the entire MRAM low power consumption and high durability. .
In the MRAM manufacturing process, it is very complicated to realize the deposition and deposition of more than 10 materials on more than 30 layers on one platform. In contrast, PCRAM and ReRAM are not so many layers, but it still has many layers of structure, including electrodes, selectors, and memory. The materials inside are very unique.
For example, PCRAM, whose material structure is GST, contains 锗 Ge, 锑 Sb, 碲 Te, is not a commonly used material, the challenge is how to deposit these composite materials and control their composition.
For mass production of PCRAM and ReRAM, the material for the application material is the Endura Impulse PVD system, which can strictly control the composition of multi-component materials while achieving excellent performance.Film thickness, uniformity, interface control.
In the general trend, large-scale mass production of new memories will start from the embedded stage. For example, TSMC will embed ReRAM and MRAM into the existing process, and then new storage technology will develop into the independent memory field because it will require more density. high.
Greet “Data explosion"The era, the chip urgently needs high computing performance, but it is in the era of Moore's Law slowing down, and the brain-like chip and quantum computing distance are too far. The new storage technology has achieved breakthroughs in equipment materials after many years of sharpening. It can catch up with the era of interconnected objects and massive data calculations, and fight on the battlefield.
When large-scale mass production of large-scale memory occurs, it is just when the domestic 3D NAND and DRAM two traditional memories are going to join the international competition arena.Although the fields of application and level are different, but coincidentally, the old and new technologies are also on the page of historical turning point, witnessing the trajectory of the global technology industry.