Onto Innovation Closes $720 Million Stake in Rigaku, Deepening X-Ray Tech Partnership
The semiconductor equipment maker acquired a 27% minority stake in the Japanese X-ray technology company from Carlyle affiliate to advance process control solutions.
Strategic Minority Investment
Onto Innovation Inc. has completed its acquisition of a 27% minority equity stake in Rigaku Holdings Corporation for approximately $720 million, the company disclosed in an 8-K filing on August 10, 2026. The semiconductor process control equipment maker purchased 61,123,436 shares from Atom Investment, L.P., an affiliate of The Carlyle Group, for 113,078,356,600 yen (8-K filing, 2026-08-10).
The transaction, first announced in April 2026, deepens an existing strategic collaboration between the two companies focused on advancing X-ray technologies for semiconductor manufacturing process control applications.
Technology Focus
The investment targets X-ray-based solutions for next-generation semiconductor manufacturing challenges. "As semiconductor innovation advances rely increasingly on more complex 3D architectures and exotic materials, our customers face growing challenges in understanding and controlling their most critical manufacturing processes," said Mike Plisinski, chief executive officer of Onto Innovation, in a statement accompanying the filing (8-K filing, 2026-08-10).
Plisinski added that the investment "strengthens our partnership, accelerates innovation, and enhances our ability to provide more holistic process control solutions to support our customers as they introduce the next generation of semiconductor technologies into high-volume production" (8-K filing, 2026-08-10).
Financial Treatment and Governance
Onto Innovation will account for the Rigaku investment under the fair value option method and will not consolidate Rigaku's financial results into its own financial statements (8-K filing, 2026-08-10). The company will nominate one director to serve on Rigaku's board as part of the arrangement.
For context, Onto Innovation carries a market capitalization of approximately $15 billion, with shares closing at $308.30 prior to the filing date, according to MarginX data.
Product Portfolio Positioning
Onto Innovation positions itself as a process control leader with offerings spanning un-patterned wafer quality, 3D metrology from nanometer-scale transistors to large die interconnects, macro defect inspection, metal interconnect composition analysis, factory analytics, and lithography for advanced semiconductor packaging (8-K filing, 2026-08-10).
The company is scheduled to present at the Silicon Photonics Global Summit on August 31, 2026, and at IMTS 2026 in September, according to MarginX data.
Transaction Background
The Share Purchase Agreement was originally dated April 21, 2026, with the seller being Atom Investment, L.P., Carlyle's investment vehicle. The completion follows a roughly four-month period from announcement to closing.
The filing includes standard forward-looking statement cautionary language regarding the company's ability to realize anticipated benefits from the investment and strategic partnership, as well as risks related to semiconductor market conditions, supply chain management, and technology integration (8-K filing, 2026-08-10).
This article was generated by MarginX from the 8-K filing on 2026-08-10. It is not investment advice.