Shulou(Shulou.com)11/24 Report--

In the last article (link), Mr. Xiaozao gave you a detailed introduction of the vicissitudes of DRAM.

DRAM belongs to volatile memory, which is often called memory. Today, let's take a look at another important area of semiconductor storage, that is, non-volatile memory (that is, flash memory cards, USB drives, SSD hard drives, etc.).

In my article "the strongest Science Popularization of Semiconductor Storage", I introduced to you that in the early days, memory was divided into ROM (read-only memory) and RAM (Random access memory). Later, it was gradually changed to more rigorous terms such as volatile memory and non-volatile memory.

█ 1950s-1970s: from ROM to EEPROM, let's start with the earliest ROM.

The exact birth time of ROM has not been recorded in detail in the available data. We just probably know that in the 1950s, after the invention of integrated circuits, there was a mask ROM.

Mask ROM, which is the real traditional ROM, is called mask model read-only memory (MASK ROM).

This kind of traditional ROM "engraves" the information directly into the memory, which is completely written, read-only, unerasable and unmodifiable. Its flexibility is very poor, if there is something wrong, there is no way to correct it, it can only be abandoned.

Later, in 1956, Zhou Wenjun (Wen Tsing Chow), a Chinese scientist of the American Bosch Arma Company, formally invented PROM (Programmable ROM, programmable ROM).

At that time, Bosch Arma had a military background and mainly studied missile, satellite and spacecraft guidance systems.

PROM, invented by Zhou Wenjun, is used in the airborne digital computer of the US Air Force intercontinental ballistic missile. It can change the physical structure of the memory by applying high-voltage pulse, so as to realize a modification (programming) of the content.

Later, PROM gradually appeared in the civilian field.

Some new types of PROM can use special equipment to fuse the fuse in the way of current or light (ultraviolet) to achieve the effect of rewriting data.

These PROM are widely used in the field of game consoles and industrial control, storing program coding.

In 1959, Mohamed M. Atalla (Mohammad Atala, Egyptian) and Dawon Kahng (Kang Dayuan, Korean), engineers at Bell Labs, co-invented the metal oxide semiconductor field effect transistor (MOSFET).

Mohammad Atala and Jiang Dayuan MOSFET were invented and ignored by Bell Laboratories. Many years later, in 1967, Jiang Dayuan and Simon Min Sze (Shi Min, Chinese) proposed that floating gates based on MOS semiconductor devices could be used in memory cells of reprogrammable ROM.

Jiang Dayuan (top left), Shi Min (top right), and the floating gate architecture they designed is an extremely important discovery. Later facts have proved that MOSFET is an important basic component of semiconductor memory cell, which can be said to be the foundation technology.

At that time, more and more enterprises (Motorola, Intel, Texas Instruments, AMD, etc.) joined the research of semiconductor storage, trying to invent semiconductor storage that can be read and written repeatedly, so as to improve the flexibility of PROM.

It was based on MOSFET's idea that in 1971, Intel's Dov Frohman (Israeli) pioneered the invention of EPROM (user-erasable PROM, erasable programmable read-only memory).

The Dorf Froman EPROM can be repeatedly reset to its unprogrammed state by exposure to strong ultraviolet light.

Also in 1971, Intel launched its own 2048-bit EPROM product, C1702, using p-MOS technology.

Shortly after C1702, in 1972, Yasuo Tarui, Yutaka Hayashi and Kiyoko Naga in the Japanese Electrotechnical Laboratory co-invented EEPROM (electrically erasable programmable ROM).

After the birth of █ 1980~1988:FLASH flash memory from ROM to EEPROM, non-volatile storage technology has not stopped the pace of progress.

At that time, although EEPROM has appeared, there are still some problems. The main problem is that the erasing speed is too slow.

In 1980, someone who changed the whole industry finally appeared. his name was Fujio Masuoka.

Fuji Masuoka is an engineer at Toshiba in Japan. He invented a new floating gate memory that can be erased quickly, that is, "simultaneously erasable (synchronous erasable) EEPROM".

The new EEPROM erases data so fast that Fujio Masuoka's colleagues think of the camera's flash and name it FLASH (flash memory).

Unfortunately, Fujio Masuoka did not get enough attention from Toshiba after he invented Flash flash memory. Toshiba paid Fuji Masuoka a bonus of a few hundred dollars and then put the invention on the shelf.

The reason is simple. During this period, Japan's DRAM is strongly crushing the United States, so Toshiba wants to continue to consolidate the dividend of DRAM and does not intend to further promote the Flash industry.

In 1984, Fujio Masuoka officially announced his invention (NOR Flash) at the IEEE International Conference on Electronic components.

At the meeting, a company took a great interest in his invention. This company is Intel.

Intel attaches great importance to the future of FLASH technology. After the meeting, they desperately called Toshiba and asked for a sample of FLASH. After receiving the samples, they immediately sent more than 300 engineers to develop their own version.

In 1986, they set up a special department to study FLASH.

In 1988, Intel produced the first commercial 256KB NOR Flash flash memory product for computer storage based on Fujio Masuoka's invention.

In 1987, Fujio Masuoka invented NAND Flash after NOR Flash. In 1989, Toshiba finally released the world's first NAND Flash product.

NOR means "NOT OR", and NAND means "NOT AND". Such naming is related to their own infrastructure.

As shown in the following figure, NOR Flash connects memory cells to the bit line in parallel. NAND Flash, on the other hand, connects the memory cells serially to the bit line.

Comparing with the NOR Flash memory, the architecture can realize random access by bit. NAND Flash, on the other hand, can only access multiple storage units at the same time.

For NOR Flash, if any memory cell is selected and opened by the corresponding word line, then the corresponding bit line will become 0, similar to the "NOR gate circuit".

NAND Flash, on the other hand, needs to make all the memory cells on a bit line 1 in order to make the bit line 0, similar to the "NAND gate circuit".

I don't understand? It doesn't matter. Remember: NAND Flash costs less than NOR Flash. (for specific differences, please refer to: the strongest entry to science popularization on semiconductor storage. )

█ 1988-2000: after the emergence of competitive FlashFLASH (flash memory) products, it has been recognized by users because of its advantages in capacity, performance, volume, reliability and energy consumption. Intel also gained an industry-leading edge and made a lot of money with its first-mover flash memory products.

Funnily enough, after Intel's success, Toshiba did not reflect on its own mistakes, but claimed that the FLASH was invented by Intel, not by its own employee Fujio Masuoka.

Toshiba didn't officially change its tune until 1997, when IEEE awarded Fujitsu Masuoka a special contribution award.

This angered Fuji Okaoka, who later sued the company and demanded 1 billion yen in compensation. In the end, he settled with Toshiba and received a compensation of 8700 million yen ($758000).

In 1988, Eli Harari (Eli Harari) and others officially founded SanDisk (SanDisk, then called SunDisk).

In 1989, SunDisk filed a patent for system flash memory architecture ("System Flash"), which combines embedded controllers, firmware and flash memory to simulate disk storage. This year, Intel began selling 512K and 1MB NOR Flash.

In 1989, another very important thing in the flash memory industry was the birth of a company called M-Systems in Israel. They first came up with the concept of flash drives, later known as flash SSD hard drives.

In the 1990s, with the outbreak of market demand for digital cameras and notebook computers, FLASH technology began to shine.

In 1991, SunDisk launched the world's first ATA SSD solid state drive (solid state disk) based on FLASH flash media, with a capacity of 20MB and a size of 2.5 inches.

Toshiba has also begun to launch the world's first 4MB and 16MB NAND Flash one after another.

In 1992, Intel accounted for 75% of the FLASH market share. In second place was AMD, which accounted for only 10 per cent. In addition to them and SanDisk, the industry has also squeezed into companies such as SGS-Thomson and Fujitsu, and the competition has gradually become increasingly fierce.

This year, AMD and Fujitsu successively launched their own NOR Flash products. The flash chip industry has annual revenues of $295 million.

In 1993, Apple officially launched the Newton PDA product. It uses NOR Flash flash memory.

In 1994, SanDisk was the first to launch CF memory card (Compact Flash). At that time, the memory card was based on Nor Flash flash memory technology and was used in products such as digital cameras.

In 1995, M-Systems released DiskOnChip, a NOR Flash-based flash drive.

In 1996, Toshiba introduced the SmartMedia card, also known as the solid-state floppy card. Soon, Samsung began selling NAND flash memory, and SanDisk launched its first flash memory card using MLC serial NOR technology.

In 1997, mobile phones began to configure flash memory. Since then, flash memory has opened up a huge consumer market after digital cameras.

This year, Siemens partnered with SanDisk to develop the famous MMC card (Multi Media Memory, multimedia memory) using Toshiba's NAND Flash technology.

In August 1999, because MMC could easily pirate music, Toshiba modified it, added encryption hardware and named it the SD (Secured Digital) card.

Later, with MiniSD, MicroSD, MS Micro2 and Micro SDHC, I believe that the post-70s and post-80s friends must be very familiar with it.

At the end of 1990s, the market scale of FLASH increased rapidly due to the outbreak of consumer digital products such as mobile phones, digital cameras, camcorders, MP3 players and so on. At that time, the market was booming and a large number of enterprises participated. Among them, the most competitive are Samsung, Toshiba, SanDisk and Intel.

In 2000, M-Systems and Trek released the world's first commercial USB flash drive, the U disk that we are very familiar with.

It also has a name, called thumb drive, at that time, the patent of U disk is more complex, a number of companies claim to own its patent. China's Ranko also obtained the basic patent of U disk in 1999.

With the rise of █ 2000~2012:NAND and the loss of NOR, NAND Flash has been on the rise since the late 1990s. Entering the 21st century, the momentum of rise is even more rapid.

In 2001, Toshiba and SanDisk announced the launch of 1GB MLC NAND. SanDisk itself launched the first NAND system flash memory product.

In 2004, the price of NAND fell below DRAM for the first time based on the same density. The huge cost effect began to push computers into the flash era.

In 2007, mobile phones entered the smartphone era, which once again had an impact on the technical pattern of the flash memory market.

In the previous functional phone era, mobile phones did not have high requirements for memory. NOR Flash is a code-based flash memory chip, which is widely used because of NOR+PSRAM 's XiP architecture (XiP,Execute In Place, on-chip execution, that is, applications no longer need to read the code into the system RAM, but can run directly in Flash flash memory).

Entering the era of smartphones, with the shortcomings of small capacity and high cost of application stores and massive APP,NOR Flash, it will not be able to meet the needs of users.

As a result, the market share of NOR Flash began to be replaced by NAND Flash, and the market continues to shrink.

Around 2008, eMMC, which began to develop from MMC, has become the mainstream technology of smartphone storage.

EMMC is embedded multimedia card (embedded Multi Media Card). It encapsulates MMC (multimedia card) interface, NAND and main controller in a small BGA chip, mainly to solve the problems of NAND brand compatibility, and to facilitate manufacturers to launch new products quickly and simply.

Then, in 2011, the UFS (Universal Flash Storage, Universal Flash Storage) 1.0 standard was born. UFS has gradually replaced eMMC as the mainstream storage scheme for smartphones. Of course, UFS is also based on NAND FLASH.

Not to mention the SSD hard disk, which basically uses NAND chips.

Around 2015, Samsung, Magnesia, Cypress and other companies have gradually withdrawn from the NOR Flash market and focused on fighting in the NAND Flash field.

█ 2012 ~ now: the current situation of the flash memory industry after the formation of the market monopoly pattern in 2011, the entire flash memory industry is in turmoil and acquisitions occur one after another.

During that period, LSI acquired Sandforce, SanDisk acquired IMFT, Apple acquired Anobit, and Fusion-io acquired IO Turbine. In 2016, an even bigger acquisition took place-Western Digital acquired SanDisk.

Through integrated mergers and acquisitions, there are fewer and fewer players in the NAND Flash market.

Finally, it formed a centralized market dominated by Samsung, Knight-errant (Toshiba), Western Digital, Magnesia, SK Hynix, Intel and other giants. Up to now, this is also the case.

These giants have a combined share of more than 95 per cent of the NAND flash market. Among them, Samsung has the highest market share, reaching 33-35%.

The arrival of the 3D NAND era, as mentioned in the previous DRAM article, around 2012, as the 2D process gradually entered the bottleneck, semiconductors began to enter the 3D era. The same is true on the NAND Flash side.

In 2012, Samsung officially launched the first generation of 3D NAND flash memory chips. Subsequently, SanDisk, Toshiba, Intel and Western Digital all released 3D NAND products. The flash memory industry has officially entered the 3D era.

Since then, 3D NAND technology continues to develop, the number of stacking layers continues to increase, and the capacity becomes larger and larger.

There are multiple routes for 3D NAND. Take Samsung as an example. In the early days, Samsung also studied a variety of 3D NAND solutions. In the end, they chose to mass-produce V-NAND flash memory with VG vertical gate structure.

At present, according to the media, Samsung has completed the development of the eighth generation of V-NAND technology products, will use 236 layers of 3D NAND flash memory chip, a single Die capacity of 1Tb, running speed of 2.4Gb / s.

Samsung has the largest market share, but they do not have the largest number of layers.

In May, Magneto announced the launch of a 232-layer 3D TLC NAND flash memory and is ready to start production at the end of 2022. South Korea's SK Hynix, but also released 238 layers of products.

NOR ushered in the second spring, let's talk about NOR Flash.

As we mentioned earlier, NOR Flash has been abandoned by the market since 2005.

By 2016, the size of the NOR Flash market had hit rock bottom.

No one would have thought that, if not, NOR Flash will have a new life in recent years.

Wearable devices such as TWS headphones, AMOLED (active matrix organic light emitting diode panel) and TDDI (touch screen) technology for mobile phone screen display, as well as the increasingly powerful vehicle electronics field, have a great demand for NOR Flash, and also led to a strong recovery of the NOR Flash market.

Since 2016, the NOR Flash market has gradually expanded.

Affected by this positive effect, coupled with the fact that many large factories have previously abandoned or reduced the size of NOR Flash (Magnesia and Cypress continue to reduce production), so some second-tier enterprises have been given the opportunity.

These include Wang Hong and Huabang in Taiwan, and Zhaoyi Innovation of Chinese mainland. The market share of these three companies is about 26%, 25% and 19%, which adds up to more than 70%.

The localization of █ FLASH flash memory in terms of localization, NAND Flash is worth mentioning is the Yangtze River storage.

Changjiang Storage was officially established on July 26, 2016 on the basis of Wuhan Xinxin Integrated Circuit Manufacturing Co., Ltd., with major shareholders including China Integrated Circuit Industry Investment Fund, Ziguang Group and Hubei Government, committed to providing integrated services for 3D NAND flash memory design, manufacturing and memory solutions.

In 2020, Changjiang Storage announced the successful research and development of two TLC / QLC products with 128layers, and launched two new consumer-grade SSD products in the titanium series.

It is recommended that you support domestic production.

By the end of 2021, Changjiang Storage has reached a production capacity of 100000 wafers per month. By the first half of 2022, mass production of NAND with 128 layers has been completed.

At present, Changjiang Storage is working hard to challenge the 232-layer NAND to narrow the process gap as soon as possible and catch up with large international companies.

As for NOR Flash, Zhaoyi Innovation (GigaDevice) has just been mentioned.

Zhaoyi Innovation, founded in 2005, is a global chip design company headquartered in China. In 2012, they were the largest local designer of code-based flash chips in Chinese mainland.

At present, they rank third in the world in the field of NOR Flash. In 2021, Zhaoyi innovative memory chips shipped about 3.288 billion (mainly NOR Flash), ranking second in the world.

█ conclusion in recent years, as you can see, with the continuous decline in the price of FLASH chips, individual households and business users have begun to adopt flash memory and SSD hard drives on a large scale. Shipments of SSD hard drives gradually exceed those of HDD mechanical hard drives. The upgrading of storage media has entered a new peak.

In the future, the market share of flash memory will further expand. Under this trend, not only the storage experience of our individual and home users will become better, but also the needs of the whole society for survival can be further met.

Semiconductor storage will play a greater role in the digital transformation of all mankind.

All right, that's all for today's article. Thank you for your patience.

Reference:

1. Semiconductor Industry memory Chip Research Framework-NOR in-depth report, founder Securities

2. "talk about Flash II: NOR and NAND Flash", Wolf, Zhihu

3. "the Development of Storage Technology", Xie Changsheng

4. "50-year history of flash memory technology", storage online

5. "another big bet by storage companies", semiconductor industry observation

6. Memory Chip Industry Research report, Guoxin Securities

7. "domestic storage awaits a revolution", Fu Bin, fruit shell

8. "there is nothing more comprehensive about semiconductor storage than this one."

9. "computer Storage History", China Storage Network

10. "3D NAND flash memory layer stacking competition, who is the best solution for 200 + layers? Flash memory market

11. "understanding 3D NAND Flash in one article", Semiconductor Industry observation

12. Baidu encyclopedia, Wikipedia related entries.

This article comes from the official account of Wechat: fresh Jujube classroom (ID:xzclasscom), author: Xiaozaojun

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