ROHM, a leading semiconductor manufacturer, was established in Kyoto in 1954. Initially offering resistors, the company has gone on to develop transistors, diodes, and ICs. Recently, there has been a focus on the development of new materials such as SiC and GaN for power semiconductors, which are expected to contribute to achieving a decarbonized society.
ROHM believes that the most important way to become a company preferred by customers and stakeholders around the world is to manufacture products with a quality-first approach. This time, we’ll take a behind-the-scenes look at how high-quality semiconductors are made.

High quality semiconductors that support everyday life

Semiconductors are ubiquitous components found in electric devices all around us, including smartphones and home appliances. And the demand for semiconductors continues to increase, particularly in the automotive and industrial equipment sectors as electrification and automation progresses.
The semiconductor manufacturing system, indispensable to our daily lives, can be broadly classified into two stages: front-end and back-end processes. In the front-end process, semiconductor chips are fabricated by forming intricate electronic circuits on a circular substrate (wafer). While in the back-end process, semiconductor chips created in the front-end are cut out, wired, and encapsulated in resin to complete the final product.
ROHM has adopted a vertically integrated production system in which all processes are performed in-house. By rigorously managing quality at each stage, ROHM is able to achieve its corporate objective of quality-first manufacturing.

Technical capabilities and the pioneering spirit of our core factories are committed to quality

One of the factories in the ROHM Group responsible for front-end processes is ROHM Hamamatsu (Hamamatsu City, Shizuoka Prefecture), which produces ICs and LEDs (with the IC production volume accounting for approximately 70% of the entire group). And there is a particular focus on analog ICs. However, the manufacturing process for analog ICs is extremely complex, entailing a series of high precision processes. For this reason, ROHM Hamamatsu is equipped with the latest device process technologies and production equipment.
The plant’s high manufacturing quality supports the ROHM Group's various challenges in technological development and commercialization for example, using BiCDMOS (Bipolar CMOS DMOS) process technology suitable for creating high-performance multifunctional analog ICs, we were the first in the world to successfully achieve mass production using larger diameter 12-inch wafers. Generally, increasing wafer size makes it difficult to guarantee product quality. But ROHM was able to overcome this considerable challenge by leveraging in-house development and tuning technologies for manufacturing equipment cultivated since the company was founded.

Deposition process of ion implanted wafers in an ultra-high temperature heat treatment furnace.
Improving and maintaining the manufacturing equipment can significantly affect wafer quality.

Taking on challenges like this in pursuit of quality have led to adoption in the automotive sector, where high quality is critical. However, as automotive products are directly related to the safety of the end user, product safety and reliability standards are understandably very strict. (Ex. AEC standards, ISO 26262, IATF 16949) High standards of quality management are required not only for products, but also for semiconductor manufacturing processes.
ROHM Hamamatsu conducts thorough quality management in all aspects, starting with plant design, equipment management that includes preventive maintenance, and process conditions. Our track record of supplying over 3 billion ICs to automotive-related manufacturers to date is a testament to our thorough quality control and ability to meet strict requirements.

Combining accumulated quality assurance with forward-thinking risk management

Gaining the trust of customers and having them adopt our products require comprehensive quality management that considers all types of risks. For example, in the process of evaluating insulated gate drivers for EVs/HEVs for automotive customers, we asked ourselves, ‘What would happen if foreign substances were introduced?’ and ‘Will screening work as in theory?’
At ROHM Hamamatsu, manufacturing was carried out based on the premise that no foreign matter is generated. At the same time, all possible measures were taken to prevent foreign matter contamination, such as sorting using defect inspection machines and screening tests at the time of product shipment. But it was also necessary to reconsider other methods to gain customer trust. To this end, members of the manufacturing and development departments worked together to come up with a response by deciding to make a prototype of a wafer with foreign particles intentionally added. Several months were then spent proving the usefulness of screening tests using the prototype wafers embedded with foreign particles, after which we were able to gain the trust of our customers.

Mr. Wada, who leads a team of engineers specializing in process design at ROHM Hamamatsu, recalls that this prototyping experience provided a great opportunity to think about ways to ensure quality and gain customer trust.

‘We have been building up our quality assurance by front-loading quality from the design stage. But to gain customer trust required going beyond this by continually engaging in forward-thinking risk management. And also by implementing technologies and systems to resolve any questions or concerns the customer may have. The combination of all these together I can proudly say forms the foundation of 'ROHM Quality'.

<Keiji Wada, Manager, Process Development Department, LSI Device Development Division,
Technology Development Segment, LSI Business Unit, ROHM Co., Ltd.>

In addition, improving the technical capabilities of the team, Mr. Wada is also focused on ‘building close relationships’ with the manufacturing section responsible for production and equipment.

‘One advantage of ROHM Hamamatsu is the close proximity of the departments to one another.
When there are issues with a product that is being mass produced, the manufacturing department is able to consult with us. In these cases, we work together to solve the problem. So being physically close I feel is actually very important in terms of improving quality.’

Development and manufacturing working together to resolve questions and concerns from customers This relationship is undoubtedly a unique advantage of ROHM’s vertically integrated production system. But more than that, the enthusiasm that arises when the company moves in one direction can help achieve customer ‘trust.’

Connecting to ‘end user satisfaction’ that goes beyond semiconductors

‘Quality First’ is ROHM’s Company Mission. ‘This doesn't simply mean supplying and mass-producing products with good characteristics, but also about building customer trust and, beyond that, achieving the satisfaction of end users,’ says Mr. Yamashita, General Manager of ROHM Hamamatsu’s LSI Production Division.

‘The other day, one of our customers came to us to conduct a new adoption audit of our parts.
He said one of the reasons for selecting ROHM was not just being able to meet the desired specifications, but also working with us to diligently respond to various issues that arise during application development.
So we were truly happy to know that what we do every day is impacting our customers.’

<Atsuhiko Yamashita, General Manager, Manufacturing Division 1, LSI Manufacturing Headquarters, ROHM Hamamatsu Co., Ltd.>

A group that creates satisfaction for people down the line from each and every product.
By linking our unique strengths to customer feedback, we believe we can contribute to a new world created by next-generation semiconductors. Our relentless challenge for ‘end user satisfaction’ continues.

A video is available on ROHM’s website that tells the story of ROHM’s manufacturing, including the individuals who are passionate about providing customers with consistently high quality.

Stories of Manufacturing

The first in the industry, which was a challenge in itself.
https://www.rohm.com/company/about/stories-of-manufacturing/wafer-production

Click here for the video.

ROHM Hamamatsu Co., Ltd.
https://micro.rohm.com/en/hamamatsu/