"Mini Wafer Fab" Helps Japan Regain its Peak?

Although Japan is currently building a 2-nanometer semiconductor fab and partnering with TSMC to build fabs in Japan, this is not seen as an effective strategy by many. For the Japanese semiconductor industry, the development of finished products (semiconductors) can be achieved by fully leveraging equipment and material strengths. The power that can take on this huge task comes from "mini wafer fabs".

It is generally believed that semiconductor production requires massive investments. On the one hand, Taiwan Semiconductor Manufacturing Company (TSMC) and other companies' semiconductor foundry businesses are developing rapidly in the industry; on the other hand, the ever-increasing demand has led to longer and longer semiconductor delivery times. To solve the problem of long delivery times and slow response speed in the semiconductor industry, the National Institute of Advanced Industrial Science and Technology (AIST) has been developing "mini wafer fabs" since 2008. "Mini wafer fabs" are characterized by the ability to produce small quantities and multiple varieties of semiconductors, bringing new trends to the semiconductor production industry.

Mini wafer fabs have traditionally only been used for prototyping, but in order to quickly apply them to mass production, AIST's researchers established "Hundred Semiconductors Company" in December 2022 (located in Kashiwa City, Chiba Prefecture, Japan). The company name contains the meaning of "providing customers with multiple types of semiconductors". Its representative director, Mr. Fumihito Kuramura, said, "We plan to create a world where anyone can design and produce semiconductors."

One of the advantages of mini wafer fabs is the ability to produce any number of semiconductors, even just one. Unlike mass production, its advantage lies in producing small quantities and multiple varieties.

Mini wafer fabs do not use traditional large-sized wafers, but instead make circuits on "Half Inch Wafers" with a diameter of 12.5 cm. The size of the production equipment is 30cm (width) * 144cm (height) * 45cm (depth), and it can perform many processes such as exposure. It can also be used in conjunction with the equipment of "Mega Fab (mega wafer fab)". Since the size of the equipment used in each process is similar, robots can be used to transport wafers between equipment.

In addition, mini wafer fabs also feature a "Mini Shuttle" that can seal "Half Inch Wafers", eliminating the need for clean rooms. While it is difficult to apply to the production of ultra-advanced semiconductors, there is plenty of capacity to produce products such as sensors and micro-electromechanical systems (MEMS).

One of the advantages of mini wafer fabs is that they can reduce equipment investment. In general, mega wafer fabs require investments of tens of billions of yen (or even higher) in equipment. On the other hand, the investment target for mini wafer fabs is 1/100 to 1/1000 of that. Because the size of all kinds of equipment is relatively small, it does not require large-scale factory land, nor does it require "photomasks" used to form lines, so the cost difference compared to mega wafer fabs is huge.

In addition, the delivery cycle of mini wafer fabs is extremely short. For large-scale semiconductor production, the time from production to delivery is extremely long; mini wafer fabs adopt a "Just In Time" mode of producing the necessary amount at the necessary time.

The above characteristics are expected to play a role in the production of small quantities and multiple varieties of semiconductors in the direction of IoT (Internet of Things). Representative Director Kuramura said, "Because the customer order volume is small, we can handle small orders that Foundries cannot handle."

Since launching the project in 2008, AIST has been developing production equipment and "Half Inch Wafers". At the same time, in order to promote mini wafer fabs as soon as possible, AIST established a "mini wafer fab promotion agency" in Tsukuba City, Ibaraki Prefecture, Japan in 2017, but the progress was slow because they could not find players who could proficiently use mini wafer fabs. Representative Director Kuramura said, "We have commercialized the production equipment and Half Inch Wafer early, but we have not found talented people and companies who can use mini wafer fabs proficiently."

To further promote mini wafer fabs, Hundred Semiconductors Company is focusing on semiconductor prototypes and orders that mega wafer fabs cannot accommodate. Mini wafer fabs are working on solving issues step by step, such as making complex business decisions (such as accurately predicting customer demand and judging the feasibility of investment) and moving from prototyping to mass production. By accepting orders that mega wafer fabs can not absorb, they will further promote mini wafer fabs.

Today, Hundred Semiconductors Company is actively promoting semiconductor design, prototyping, and mass production activities. The goal is to share experience with customers in order to achieve the goal of popularizing production technology. At the same time, they will continue to improve the speed of improvement of prototypes to quickly move towards mass production.

In addition, AIST is also promoting the development of design software that can be used for mini wafer fabs. Its goal is to develop a PDK (Process Design Kit) for complementary metal oxide semiconductors (CMOS) within a year. Also, to make it easier to use, they are considering standardizing basic line designs and prioritizing their application in R&D. In the future, prototyping will be carried out at the AIST Seaside Urban Center (Koto-ku, Tokyo) and Tsukuba Center (Tsukuba City, Ibaraki Prefecture).

In addition, AIST is exploring new applications. For example, considering the issue of power consumption, AIST is discussing filling the gap that integrated circuits (FPGA, programmable) cannot meet, with the goal of providing and popularizing more design and process development services. AIST said, "We can flexibly respond to and meet customized requirements."

AIST has completed the development of front-end processes (forming lines), bonding, and other processes. The goal for the next five years is to integrate packaging substrates onto "Half Inch Wafers". This will enable semiconductors to be packaged in smaller areas and reduce power consumption while exploring more application scenarios.

To further promote mini wafer fabs, AIST's goal is to expand the production volume of "Half Inch Wafers" to achieve an annual production of 50,000 pieces after five years. In the future, they not only plan to have their own production base but also to carry out production on their own. Representative Director Kuramura pointed out, "For companies participating in the promotion agency, mini wafer fabs are just one option for them. We will fully leverage the role of leaders to promote this production model."

The main theme of the semiconductor industry has always been "mass production, mass consumption", but mini wafer fabs can provide customers with the required quantity when necessary. However, on the other hand, it also faces the challenge of digging deeper into the customer base and cultivating a customer base with multiple needs. At the same time, AIST is also working hard to develop technology to provide semiconductor production and design services for many customers.