Rohm 扩大封测外包，联手 Tata Electronics 与 Suchi Semicon 布局印度 OSAT

Japanese chipmaker Rohm Semiconductor is expanding its use of outsourced semiconductor assembly and test (OSAT) facilities, starting with existing products and local demand while continuing to keep wafer fabrication in-house. In India, the company has announced partnerships with Tata Electronics and Suchi Semicon, initially assigning different package types to each partner.

“Tata is for TOLL, and Suchi is for TO-252 packaging,” Makoto Terada, managing director of Rohm Semiconductor India, told EE Times. TOLL is widely used in the two-wheeler market, while Terada said the main customer base for TO-252 is “more like four-wheeler.”

The move is part of a broader change in Rohm’s manufacturing strategy. The company has historically manufactured most of its chips in its own fabs, but has increased its use of external manufacturing partners in recent years. It is evaluating the two partnerships to prototype and benchmark the capabilities of the Indian OSATs, with the aim of starting production for the local market before potentially expanding production to serve global demand.

“There are so many OSAT companies and partners, but at this moment, today, we do not know yet who will be the best,” Terada said.

The company started with two partners to move faster. Asked whether both partners could eventually handle the same packages, Terada said, “That is possible,” but added that it would depend on demand.

Asked why Rohm selected Tata and Suchi, Terada said, “They are ready,” adding that the packages Tata is preparing match Rohm’s portfolio requirements for India.

The partnership with Suchi Semicon also includes joint business development for locally manufactured semiconductors and joint marketing that draws on Suchi Semicon’s local expertise.

Qualification before mass production

Rohm is not starting its Indian OSAT partnerships with new designs. “We are now requesting those OSAT partners to package existing products, legacy products first,” Terada said.

These products have a long production history within Rohm, while the Indian OSATs are new to the company. The company is therefore evaluating how well the partners can handle the packaging of existing products.

The first products will be power MOSFETs. Terada said Rohm’s focus remains analog and power, and Terada did not indicate any plans for advanced packaging in India at this stage.

Rohm is applying its existing quality process to the Indian OSAT partners. “Our quality sections are visiting them from time to time, and at the end of the process, the qualification has to be done,” Terada said.

Thermal management is also part of the evaluation. “Thermal management is a critical issue,” Terada said. The qualification process remains at an early stage as Rohm evaluates the maturity of the OSATs.

Terada said Rohm has proposed a talent development program to the Government of India. If supported by the government, engineers from OSATs or other companies could train at Rohm facilities for several months or years.

Wafer fabrication remains in-house

While Rohm is outsourcing assembly and test, Terada said the company does not plan to outsource its wafer process through the current India strategy. “The wafer process will remain inside,” he said.

Production control will also remain with Rohm. “Production control has to be done by ourselves, but the outsourcing ratio might be increased,” Terada said.

The decision on which processes to outsource depends on the region, location, and application, he said. Capital efficiency, capacity, and supply chain requirements all play a role. Asked whether the decision was based on one of those factors, Terada said, “A mix of them.”

The approach is not new for Rohm. The company began outsourcing back-end work several years ago through partners in ASEAN countries and China. “Now those are coming to India,” Terada said. He described the model as “working very well.”

Rohm is also increasing its use of external manufacturing elsewhere in its network. The company is folding its Japanese manufacturing subsidiaries into a wafer process company and an assembly company, starting April 1, 2026, with LAPIS and the Shiga facilities to follow in 2027. Its current midterm plan also calls for moving production lines and consolidating sites.

Rohm reported a net loss of ¥158.4 billion (~$1 billion) for the fiscal year ended March 31, 2026, driven by an impairment related to its SiC business. However, net sales increased 7.3% year over year to ¥481.1 billion (about $3 billion), with the company employing 21,756 people across 97 locations.

The company has also moved to outsource production at a facility it previously owned. In May 2026, Rohm agreed to sell all of Rohm Electronics Dalian to Dalian Chengyue Precision Components Industry for about ¥4.2 billion (~$27 million) and outsource manufacturing at the site afterward, citing lower fixed costs.

Rohm is also using partnerships elsewhere in its power semiconductor business. HAIMOSIC, a Shanghai-based joint venture with Zhenghai Group, makes SiC power modules. Rohm and Toshiba agreed in 2023 to use each other’s production capacity for power devices. In March 2026, Mitsubishi Electric, Rohm, and Toshiba signed an MOU to discuss merging their power device and semiconductor businesses.

The company is taking a different approach for gallium nitride (GaN) technology. Rohm said it plans to license TSMC’s GaN process technology and transfer it to its Hamamatsu facility, with the aim of establishing an end-to-end GaN production system by 2027 for applications such as AI servers and electric vehicles.

The GaN move builds on Rohm’s collaboration with TSMC, including its use of TSMC’s 650V GaN process since 2023 and an automotive GaN partnership launched in 2024. Once the technology transfer is complete, the automotive GaN partnership will conclude, while the companies will continue working together on more efficient and compact power supply systems.

India localization drives OSAT strategy

For India, Terada called supply chain resilience and the government’s localization push “the biggest reason” for moving assembly and testing into the country. A second reason, he said, is to win more designs from end customers.

Terada said government support, including the production-linked incentive (PLI) scheme and the domestic value-addition concept, also encourages customers to localize manufacturing.

Rohm also sees a visibility benefit from being an early participant in India’s semiconductor industry. “We wanted to be a kind of first adopter for the semiconductor industry in India,” Terada said.

Rohm’s focus on local customers was evident in its demonstrations at electronica India, where the company presented power, analog, and embedded solutions for Indian automotive and industrial applications.

One demonstration featured an electronic fuel-injection (EFI) reference design with the UCHIP2 (EFI driver IC) evaluation board. The system was designed and is currently being validated in India, while manufacturing is handled in Japan. It is intended for cars, two-wheelers, and three-wheelers with engine capacities up to 300 cc.

Vishal Jain, large-scale integration (LSI) manager for Analog LSI design at Rohm Semiconductor, told EE Times that the reference design combines Rohm ICs, intelligent power devices, gate drivers, and high-voltage IGBTs and MOSFETs for engine control, fuel injection, and spark generation. It also incorporates protection functions including under-voltage, over-voltage, over-current, open-load, and thermal protection, along with a watchdog timer for monitoring MCU performance.

Rohm also showcased a three-wheeler EV concept model developed at its India design center. The platform brought together the company’s power and analog devices in a compact 48V EV architecture. Its traction motor and inverter system uses 100-V automotive MOSFETs, including TOLL-package EcoMOS devices, for 5.5 kW of continuous power and 8.5 kW of peak power.

The vehicle demonstration also incorporated display controllers, SerDes ICs, and image-adjustment LSIs for the cockpit and camera displays, automotive-grade speech synthesis hardware for the acoustic vehicle alerting system, and multi-channel LED drivers for exterior lighting.

A separate demonstration showed Rohm’s Solist-AI technology for on-device AI. The predictive-maintenance demonstration used a fan motor to show how the system can learn an equipment’s normal vibration pattern and identify deviations as the vibration changes.

Solist-AI integrates Rohm’s AxICORE-ODL dedicated AI hardware accelerator into an MCU, allowing learning and inference to be performed on the device without a network connection or cloud server. The company said that the technology can use inputs including acceleration, temperature, current, voltage, sound, and light to detect abnormalities in applications such as motor bearing damage detection and industrial equipment monitoring.

India remains an early-stage market for Rohm

TO-252 is already a package that Rohm supplies worldwide. “If we manage launching in India, that is what I am expecting to expand to global [markets],” Terada said. “That is possible, but we start from the local demand.”

Rohm has not set a production volume target for its Indian OSAT partners. Asked how much of Rohm’s production could eventually be packaged and tested in India, Terada said, “I do not know how much we can support with local manufacturing.”

The potential expansion of local production comes as Rohm continues to build its business in India, which Terada described as an emerging market for the company. “It is an emerging market, but still, it is at an early stage for us compared with other regions,” he said.

Power devices are Rohm’s main target worldwide, but the application mix in India differs from other markets. Two-wheelers are the company’s primary target in India, while other regions lean more toward four-wheelers. “Two-wheelers are our primary target [for Indian customers],” Terada said.

Rohm has “many engagements with almost all OEMs and a few others [Tier 1s],” he said.

AI data centers are another emerging opportunity. Rohm is promoting MOSFET power products and analog products for the sector. “Not directly the hyperscalers, but we are promoting our power devices to power equipment or unit suppliers, such as global players,” Terada said.

Also read:

Rohm Joins Toshiba and Mitsubishi to Create a Power Chip Titan

Tata Electronics to Assemble and Test Automotive MOSFET

India’s OSAT Ambitions: Flying High or a Flight Risk?

India’s OSAT-ATMP Build-Out: From Legacy Packages to 2.5D

ASSEMBLY AND TEST, ELECTRONICA, INDIA, OSAT, POWER DEVICES, SEMICONDUCTORS, SOC

ROHM SEMICONDUCTOR, SUCHI SEMICON, TATA ELECTRONICS