South Korea was once an agricultural country that began its industrialization process in the 1960s. The history of its semiconductor industry began in 1965, starting with semiconductor assembly

South Korea was once an agricultural country that began its industrialization process in the 1960s. The history of its semiconductor industry began in 1965, starting with semiconductor assembly. Among many chip sectors, South Korea's most successful achievement is its position in the storage field.

When the concepts of DRAM and flash memory began to develop in the 1970s and 1980s, there was no sense of existence in Korea. Before 1984, American chip manufacturers represented by Intel were the main players in memory chips. Between 1984 and 1994, Japanese chip manufacturers launched a fierce attack on DRAM, surpassing the United States to dominate the memory market. As a result, Intel, which started with storage in 1985, withdrew from the DRAM business and began to focus on CPUs. However, in the decade from 1994 to 2004, South Korean memory chip manufacturers made it all the way to the main stage of storage, and it has been going on until now.

Geographical distribution of global memory DRAM and NAND flash memory revenue

In the field of traditional storage, South Korea has already won once. A small country like South Korea has contributed nearly two-thirds of the world's memory chips, and Samsung and SK Hynix are the leaders of the storage industry in South Korea and even globally. According to data from 2022, Samsung Electronics and SK Hynix account for approximately 50% of the global NAND flash memory chip market share. In the DRAM field, these two companies dominate, occupying nearly 70% of the global market share. Now, how can South Korea win again in the storage field?

Several Reasons for Korea's Great Success in Storage Chips

First of all, let's take a look at how South Korea has achieved success in the field of storage chips?

Large R&D investment:In 1983, Samsung actively entered the semiconductor field, starting with DRAM. SK Hynix was also born at this time, established by Hyundai Motor. Between 1987 and 1992, Samsung's average capital expenditure accounted for 39.8% of revenue, almost twice the industry average of 21%. The research and development investment in DRAM is also twice that of other competitors. It was these massive investments that made Samsung the world's highest revenue DRAM manufacturer in 1992. Today, Samsung holds 43% of the global DRAM market share (according to ICInsights in 2021).

Timely transition to next generation wafer size:South Korean DRAM manufacturers such as Samsung are the first to invest in larger diameter wafers. This strategy brings substantial returns as equipment suppliers offer discounts to the initial few (adventurous) customers. In the early 1990s, the industry could choose to shift from 6-inch wafers to 8-inch wafers. But this period coincides with a downturn in the DRAM market, and Japanese chip manufacturers are particularly hesitant to invest in 8-inch production capacity. However, Samsung, with its strong capital, has no such concerns and is the second company in the industry (second only to IBM) to switch to 8-inch wafers. As a result, Samsung received a 15% discount on the price of 8-inch devices and early benefited from the 1.8 times higher productivity of 8-inch manufacturing. In the fiercely competitive DRAM industry at that time, both the advantage of device discounts and the improvement of yield rates gave Samsung a considerable taste of sweetness.

Similarly, Samsung was an early participant in the transition from 8-inch to 12-inch wafers in the early 2000s. Samsung received a 24% discount on device prices, and after transitioning to 12 inches, Samsung's manufacturing productivity increased by 2.3 times. This helped Samsung expand its market share in the early 2000s.

Expanding production against the trend and defeating competitors in a price war:Around 2008, DRAM prices fell below cost prices, but Samsung Electronics used all the profits from the previous year to expand production capacity and launched a price war by increasing production capacity, defeating Germany's Qimonda and Japan's national team Erbida in one fell swoop.

Advantages of low-cost manufacturing:In terms of production and manufacturing, South Korea has lower manufacturing costs than the United States and Japan, with corporate income tax in the 25% range in South Korea and 35% -40% in the United States and Japan. The labor cost in South Korea is also significantly lower. In addition, at that time, the South Korean government provided support such as a 5-10 year tax holiday and low interest loans to enterprises. All of these factors have led to a lower cost of manufacturing storage chips in South Korea, which has also played an important role in the success of the storage industry in South Korea.

The success of South Korea in storage chips is also influenced by many factors, including favorable timing, favorable geographical conditions, and government support. Overall, the rise of the semiconductor industry in South Korea is inseparable from the support and efforts of various parties.

Continuing to advance in the storage field

In recent years, with the rise of China and other countries in the storage industry, the position of South Korea's storage industry has become unstable. Therefore, Korean storage enterprises need to strengthen technological innovation and improve product competitiveness in order to occupy a place in the fierce market competition.

In the field of NANDFlash, the most important thing is continuous performance improvement and cost per bit reduction. Therefore, in order to reduce cost per bit, it is necessary to increase the number of stack layers while reducing the spacing between stack layers. Nowadays, the competition among manufacturers in building 3DNAND buildings is extremely fierce. SK Hynix is in a leading position in increasing the number of layers in 3DNAND. At present, SK Hynix's 3DNAND memory has 238 layers. In November 2022, Samsung announced the initial mass production of its approximately 236 layer 3DNAND memory, which is its eighth generation V-NAND. Moreover, SK Hynix submitted a paper at the ISSCC2023 conference, showcasing their development of over 300 layers of 3DNAND technology that can read data at a speed of 194GBps.

In the field of DRAM, its evolution and expansion in technology are showing a slowing trend. Techinsights analysts point out that as the 10nm process approaches, DRAM's definition of circuit patterns on wafers has approached the limits of basic physical laws. Due to challenges in process integrity, cost, unit leakage, capacitance, refresh management, and sensing margin, the scaling of DRAM storage units is slowing down. And even through EUV lithography, planar scaling is not enough to provide the bit density improvements required by the industry in the next decade.

In order to further expand DRAM, thereby reducing costs and power consumption, and improving speed. Single chip 3DDRAM technology has become a technology being explored by storage giants. Yole reported in early 2022 that Samsung Electronics is preparing to develop the world's first 3DDRAM and is accelerating its development. SK Hynix is also investing heavily in it. But there is still a lot of uncertainty about the future of 3DDRAM.

In short, in the traditional storage field, storage manufacturers still need to constantly innovate materials, processes, structures, and products to challenge the expansion limitations of DRAM and NAND technologies in order to continue to maintain their leading position in the storage field.

Korea Wants to Win Again by Developing New Storage Technologies

With the development of next-generation innovative technologies such as large-scale artificial intelligence and machine learning, memory technology not only needs to provide all traditional values such as high performance, low power consumption, low cost, and high capacity, but also needs to provide more intelligent solutions to effectively eliminate the inherent problems of so-called memory walls.

Therefore, while ensuring the continued development of traditional DRAM and NAND storage chips, South Korea recently released its first chip industry research and development blueprint. One of the important plans in this blueprint is to develop the next generation of storage chips, including next-generation chip devices, ferroelectric RAM, magnetic RAM, phase-change RAM, ReRAM, or resistive random access memory.

Samsung and SK Hynix, as two key pillars of South Korea, have invested a large amount of funds in researching new memory technologies such as RRAM, PCM, and MRAM.

In the field of new storage, Samsung is pursuing MRAM. At IEDM2022, Samsung introduced its progress on MRAM. Samsung researchers introduced information about 28 nanometer embedded magnetic random access memory (MRAM) technology. The write energy of this device is only 25pJ/bit, with effective power requirements of 14mW (read) and 27mW (write), and a data rate of 54MB/s. The device is packaged with 30 square millimetre, has a capacity of 16Mb, and has very high durability (> 1 E14 cycle). Abstract: After reducing the MTJ to a 14 nanometer FinFET node, the area reduction increased by 33% and the reading time increased by 2.6 times. Samsung is considering MRAM as a low leakage working memory (cache) for AI and other applications that require large amounts of data. Samsung researchers claim that the product they have developed is the smallest and most energy-efficient non-volatile random access memory in history.

The above figure shows a cross-sectional TEM view of the Samsung eMRAM bit unit array embedded in a 14 nanometer logic platform

At the same time, Samsung has also conducted in-depth exploration in the field of in memory computing. In January 2022, Samsung's research team published a paper in the journal Nature titled "Cross array of magnetoresistive storage devices for memory computing". In this paper, it is pointed out that they have successfully developed an MRAM array chip that demonstrates memory computing by replacing the standard "current and" memory computing architecture with a new "resistance and" memory computing architecture, which solves the small resistance problem of a single MRAM device. According to the data provided by the research team of this Korean multinational company, by evaluating its performance in artificial intelligence computing, the memory has successfully passed the test, achieving an accuracy of 98% when manually inputting numbers for classification and 93% when detecting faces in different scenarios. By introducing MRAM (memory that has already been commercially produced in system semiconductor manufacturing) into the field of memory computing, this work extends the forefront of next-generation low-power artificial intelligence chip technology.

SK Hynix, on the other hand, favors ferroelectric memory (FeRAM) and phase change memory (PCM).

As early as 2000, SK Hynix, still a modern electronics company, developed a new type of ferroelectric RAM; In 2001, SK Hynix developed 1MFeRAM, which uses 0.35 micron process technology and operates at a speed of 100ns (1ns=1/1 billion seconds) in the range of 3V to 5V; In 2003, SK Hynix launched the world's first commercial megabyte FeRAM, with FeRAM samples using 4Mb and 8Mb densities and manufactured using Hynix's advanced 0.25um process technology. The operating voltage is 3.0V, the data access time is 70 nanoseconds, and it can perform 100 billion read/write repetitions. This is an important industry milestone.

SK Hynix's first commercial FeRAM (ferroelectric RAM)

SK Hynix is still exploring the application of ferroelectric materials to traditional 3DNAND architectures. As 3DNAND continues to increase bit density by stacking more layers, it faces challenging process complexity, such as high aspect ratio contact etching and thin film stress control. The degradation of equipment performance caused by unit proximity is also an issue. SK Hynix is addressing these obstacles by exploring stack height scaling, new materials, and a new 3DNAND unit architecture. On IMW2022, SK Hynix demonstrated 3D ferroelectric NAND devices with multi-level functionality using the traditional 3DNAND manufacturing process.

Applying Ferroelectric Materials to Traditional 3DNAND Architecture

In the field of phase change memory research, SK Hynix began collaborating with IBM to develop PRAM as early as 2012. In 2021, SK Hynix announced that the company had applied PUC (PeriUnderCell) technology and designated algorithms to its PRAM, meeting its performance and cost classification as storage memory. PUC technology places peripheral circuits on the unit below the unit to reduce chip size and improve productivity. SK Hynix stated that compared to memories below 10 nanometers, PRAM has fewer scaling limitations. It is also amorphous, making it easy to stack in 3D. PRAM combines the advantages of DRAM and NAND flash memory and is considered a key technology for data center business.

Image source: SK Hercules

SK Hynix's Revolutionary Technology Center (RTC) has been researching in memory analog computing (ACIM), and SK Hynix believes that in memory computing may bring value to both computing and memory. They have successfully demonstrated 16 levels of RRAM based synaptic unit platforms, which have good set/reset characteristics and can be embedded into CMOS technology.

epilogue

With the gradual saturation of traditional storage expansion such as NANDFlash and DRAM, new storage technologies have become a point that Korean players in the storage field have to pay attention to. However, the research on these new storage technologies is not intended to replace traditional storage, but to better supplement it in terms of latency and productivity. In the future, different types of storage technologies will coexist to meet the different needs of future market applications. Can South Korea win again with its layout in new storage and other fields?

reference

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