Mimasu Semiconductor Industry

Mimasu is a Japanese specialist in precision silicon wafer processing, with a business that began in 1966, before semiconductors were widely known. Its core activity is contract polishing and finishing of prime silicon wafers for Shin-Etsu Handotai, the group's wafer manufacturer, alongside a reclaim business that restores customers' used test and monitor wafers to as-new quality. Two smaller divisions broaden the model. One is a technical trading house selling measuring, testing and semiconductor equipment. The other is an engineering unit building spin processors and wet-process tools, used both by customers and in-house. Revenue reached JPY 95.0 billion in the year to February 2026. The company has concentrated its manufacturing in Takasaki and committed JPY 77 billion to a dedicated 300mm plant. Full ownership by Shin-Etsu since 2024 has turned it from an independent listed processor into an integrated capacity arm of the world's largest silicon wafer group, with far less public disclosure.

The company's own description. The FY5/2024 annual securities report says Mimasu's three divisions are deeply engaged in the semiconductor industry and work together "as a trinity". It puts safety first, conducts fair business and aims to raise corporate value. The stated focus is the core semiconductor materials processing business and continued refinement of the advanced processing technology that underpins the industry, delivering high quality and low cost. The company's name reflects a founding spirit in which shareholders, customers and the company are bound by trust and prosper together.

What the company does. The Semiconductor Division polishes and finishes silicon wafers. Prime wafer processing is commissioned by Shin-Etsu Handotai, which supplies the material. Mimasu therefore earns mainly a processing fee (加工料収入) rather than selling wafers it owns, which is why its balance sheet carries little prime wafer stock relative to revenue. In reclaim, Mimasu collects test and monitor wafers used by device makers and restores them to quality equivalent to new test wafers so they can be used repeatedly.

The Industrial Sales Division (産商事業部) calls itself a "technical trading company". It sells instruments, testing machines, precision equipment and semiconductor process tools from third-party makers, and also sells the Engineering Division's products. The Engineering Division designs and builds automation and wet-process equipment. It has no external revenue of its own, because its products reach customers through Industrial Sales or go to the Semiconductor Division.

Revenue model. Mimasu's income falls into three reported types, shown below from the annual securities reports. Revenue is transactional or contract processing. There is no subscription or licensing line.

Merchandise sales (JPY M): FY2021: 36942; FY2022: 21751; FY2023: 31405; FY2024: 37089

Product sales (JPY M): FY2021: 1581; FY2022: 4235; FY2023: 6087; FY2024: 4943

Processing fees (JPY M): FY2021: 46527; FY2022: 48445; FY2023: 53444; FY2024: 47076

Total sales (JPY M): FY2021: 85051; FY2022: 74432; FY2023: 90936; FY2024: 89109

Fiscal years in this table end on 31 May. From FY5/2022 the revenue recognition standard moved agency transactions to a net basis, which cut that year's sales by JPY 19,488 million, of which JPY 19,433 million fell in Industrial Sales. FY5/2021 was not restated, so the fall in merchandise sales between those two years is mainly accounting.

Value chain position. Mimasu sits between crystal growth and device fabrication. Shin-Etsu Handotai grows and supplies silicon, Mimasu performs high-precision flatness and cleaning steps, and the finished wafers go to device makers. In reclaim it sits after the fab, in a closed loop with device makers. Its equipment and trading activities supply the same fabs and laboratories.

Customer types and end-markets. Shin-Etsu Handotai is the dominant customer. The trade receivable ledger at 31 May 2024 also named Hitachi High-Tech (JPY 7,739 million), Renesas Electronics (JPY 2,223 million), Shin-Etsu Chemical (JPY 1,811 million) and Kioxia (JPY 1,482 million). Notes and electronically recorded receivables named Sony Semiconductor Manufacturing, ROHM, Sanko Shoji, Mitsubishi Materials and Nipro Medical Engineering. Recruitment materials describe customers as domestic and overseas device makers plus private companies, universities and public research institutes. End-markets include logic, memory, power devices, automotive testing and scientific research.

Independent characterization. Mimasu is best understood as a captive-plus business. Its economic core is a capital-intensive processing relationship with its parent, surrounded by a merchant reclaim franchise, a low-capital distribution arm and a niche equipment maker. Since the 2024 buyout, the question for an outside observer is no longer standalone valuation. It is how much of Shin-Etsu's 300mm finishing capacity runs through Takasaki and whether third-party reclaim stays neutral inside a wafer-maker's group.

Stated themes. The FY5/2024 report set out the last formal public strategy. The company would allocate resources selectively to semiconductor materials processing and aim to be a strong business not swayed by cycles. By division:

• Semiconductor Division: build on large-diameter processing, establish more precise and productive processes, expand capacity and improve QCDS.

• Industrial Sales Division: anticipate user needs in semiconductors and build a stable base outside them.

• Engineering Division: specialise as a development unit, jointly promote spin processors and develop equipment for in-house use.

Management targeted improvement in return on assets and return on equity, but gave no numeric medium-term targets.

Strategy under Shin-Etsu. The tender documents remain the most detailed public statement of direction. Shin-Etsu and Mimasu identified these aims:

Timely allocation of wafer capacity: Intended effect: Share production technology, equipment and resources; optimise production, inventory and logistics; strengthen supply chains

Talent exchange: Intended effect: Joint development for higher-density, faster, lower-power devices; use of the group's Gunma sites

Broader wafer range: Intended effect: Combine product knowledge, including cross-selling and AI-related wafers

Lower investment cost: Intended effect: Use group funding for large capex rather than external borrowing

Reclaim technology applied to new wafers: Intended effect: Use polishing, cleaning and film technology to cut energy in new wafer production and support green transformation

Spin processor overseas sales: Intended effect: Use Shin-Etsu's overseas customer network

Disaster risk diversification: Intended effect: Spread supply chain and manufacturing risk

Lower listing costs: Intended effect: Redirect listing-related resources to business growth

Mimasu also stated it aims to expand 300mm reclaim share using the group's customers and sales network, and that future investment would be needed for automation and high precision as bonded-wafer and similar technologies advance. Shin-Etsu said the existing business model and customer relationships would stay in place for the time being.

Other initiatives in the last 24 months. These are the Multi-Stakeholder Policy (January 2025), annual updates to environmental data (May 2025 and June 2026) and a Facilities Headquarters (June 2026). The last of these suggests the capacity programme is a standing management priority. Sustainability priorities are environmental protection, products that support sustainable society and a good workplace with long-term talent.

Targets and plan. No current targets are public. The JPY 77 billion plant is the largest project in the company's history. The business plan given to the tender adviser, which management said did not presume the transaction, ran as follows. Fiscal years end May, as planned before the change of year end.

Revenue (JPY M): FY2025: 84367; FY2026: 89891; FY2027: 101983; FY2028: 108218; FY2029: 112533

Operating income (JPY M): FY2025: 10232; FY2026: 11956; FY2027: 14662; FY2028: 16073; FY2029: 17534

EBITDA (JPY M): FY2025: 21232; FY2026: 21026; FY2027: 32666; FY2028: 35133; FY2029: 34597

The plan's implied depreciation doubles from about JPY 9 billion to about JPY 18 billion from FY2027, showing when management expected the new plant to reach the income statement. In practice, sales for the year to February 2026 of JPY 95.0 billion were ahead of the FY2026 plan, while operating income of JPY 9.7 billion was behind it. The periods differ by three months, so the comparison is indicative.

Pricing is not publicly disclosed for any line. The company states it has obtained certification under the international quality management system standard for prime wafer production.

Semiconductor Division

The company says the CO2 avoided through reclaimed wafers exceeds its total emissions. Shipments of reclaimed wafers have also been shifted from aircraft and truck to ship and rail.

Engineering Division products

The MSE series handles silicon etching after backgrinding and various metal etches, offers infrared real-time or EL rate-managed thickness endpoint detection, holds warped thin wafers on a fin chuck for simultaneous two-sided rinsing, and uses a "hanging hand" for thin wafer handling. The MSC series handles resist stripping, polymer residue removal and metal impurity cleaning, with two-fluid, ultrasonic and ozone options. Spin processors are used to make IGBTs for electric and hybrid vehicles, and Mimasu's tender documents say they are highly regarded by domestic power semiconductor customers. Launch years by model are not publicly disclosed.

The company site also lists pure water plants and wastewater treatment facilities in the Engineering Division's design scope, along with manufacturing, inspection and test systems.

Industrial Sales Division catalog

Principal supply partners listed by the company include ULVAC, ESPEC, Evident, Instron Japan, Ono Sokki, Organo, Komatsu NTC, SCREEN Holdings, CHINO, DISCO, Tokyo Seimitsu, Onto Innovation Japan, Nikon, JEOL, JASCO, Pall Japan, Hitachi High-Tech Analysis, Buehler, Mitutoyo and Rion.

Mimasu's own disclosure is sparse since delisting, so the register includes industry and parent events that directly affect it.