Technological development highlights

Reducing electricity used in semiconductor coating and developing—creating more environmentally friendly production equipment

As demand for cutting-edge semiconductors grows, the environmental impact of their manufacturing has become a more pressing issue for both the industry and society at large. The SCREEN Group is advancing sustainable management aimed at ongoing growth. Our medium-term management plan, Value Up Further 2026, is aimed at creating long-term solutions to environmental, social, and governance (ESG) issues. As part of this plan, we have established non-financial targets under the framework of Sustainable Value 2026.

In this interview, we heard about efforts at SCREEN Semiconductor Solutions to develop coater/developers that use less energy with the aim of reducing environmental impact, as well as the resulting achievements.

 

H.M., Innovation Enablement Department, R&D Strategy Operations, SCREEN Semiconductor Solutions Co., Ltd.

 

 

In cutting-edge semiconductors, the increase in manufacturing processes has led to increased resource consumption

To begin, could you tell us about your work?

 

I work at SCREEN Semiconductor Solutions in selecting research topics for collaboration with external organizations, managing related activities, and selecting themes and topics that are attracting attention internally to develop into concrete businesses.

Last year, we developed coater/developer technologies that could become businesses in two or three years. This year, as we hone strategy for the coater/developer business, including longer-term strategy, we are advancing joint development with our partner, imec. Specifically, this collaboration entails providing systems we have developed to jointly evaluate their actual performance with imec. I manage these efforts.

The SCREEN Group is currently working toward the targets of Sustainable Value 2026. Aiming for net zero greenhouse gas emissions by 2050, our current target is to reduce these emissions 58.1% from 2019 levels by March 2030.

My job is now to apply innovation to break through barriers and transform them into business opportunities.
 

H.M., Innovation Enablement Department, R&D Strategy Operations, SCREEN Semiconductor Solutions Co., Ltd.

 

 

What major challenges do you see in cutting-edge semiconductor manufacturing processes?

 

Today’s cutting-edge semiconductors require more processes to manufacture than ever before. Each wafer takes more processing to complete, requiring more materials and resulting in higher costs. This is why, even for wafers of the same size, those made with state-of-the-art processes cost more.

At the same time, besides greater costs, increased processing also results in greater environmental impacts. As such, developing techniques to reduce both costs and environmental impact is a shared challenge faced by the entire semiconductor industry.

 

 

Why are coating and developing processes a promising target for reducing environmental impact?

First, could you explain the role of coater/developers in semiconductor manufacturing and the sources of negative environmental impacts in coating and developing processes?

 

Coater/developers have two functions: the coater, which creates a photosensitive film, called a photoresist, on the wafer, and the developer, which removes the unnecessary parts of the photoresist after the wafer passes through an imaging system.

One source of environmental impact in coating and developing processes is the waste treatment of the chemicals used.

Another is the electricity used. Annealing to sinter films accounts for about half of the power used in coater/developers. This includes film sintering processes at temperatures of over 300°C and high-precision sintering processes that control temperature uniformity within 1°C. Maintaining consistent processing temperatures in these processes requires a great deal of power. Furthermore, even when equipment is in standby and wafers are not being processed, power must be constantly supplied to the equipment’s heaters to maintain high temperatures and precise temperature uniformity, further increasing the total energy consumption of these processes.

 

What was the focus of your initiatives to address these issues?

 

In the past, our approach to reducing environmental impact has centered on reducing the use of expensive chemicals. Reducing the amount of chemicals used cuts down on not only cost, but also waste, thereby reducing environmental impact.

Sustainable development efforts in coating and developing go back more than 20 years, most commonly in reducing the use of developer solutions and other chemicals. Compared with past products, these improvements greatly reduced the amount of chemicals required. However, after decades of development, there was not much room left for improvement on this front. We needed a new approach.

We therefore turned our sights on another aspect of reducing environmental impact: reducing power consumption. In particular, we were spurred to action by the surge in momentum toward reducing electricity use in Japan amid the power shortages following the Great East Japan Earthquake and by sharply rising energy prices around the world due to unrest overseas over the past few years. We decided to focus on reducing power used in annealing. Specifically, we began working in earnest to develop a method for achieving a similar effect, without using heat, to conventional annealing used on the underlying layer that serves as the base of the photoresist.

We had the idea of using photocrosslinking, in which the coating film is cured using energy in the form of light, rather than heat. While annealing equipment consumes energy even when in standby to maintain the necessary temperature, the light used in photocrosslinking technology need only be turned on when in active use, reducing the amount of power used.

At the same time, a chemical fluid manufacturer we work with also had ideas for materials that would work with photocrosslinking. The fundamental pieces we needed were thus all in place, which made this project possible.

 

 

What kinds of environmentally friendly technologies are employed in SCREEN Semiconductor Solutions’ coater/developers?

 

The conventional process required temperatures of over 200°C to sinter the base layer under the photoresist. We developed a state-of-the-art technology to form this layer using room-temperature reactions, instead.

We already used photocatalytic reactions in photolithography, and we had heard from our material manufacturer that thermal crosslinking reactions (to keep the film from being dissolved by the solvent) and crosslinking reactions using photocatalysts were easy to use, so we decided to try it. SCREEN Semiconductor Solutions created a light irradiation unit that can be used in semiconductor device manufacturing, and we jointly developed the materials and system with imec.

 

 

Collaborating with the imec SSTS program to evaluate the new approach

I understand that collaboration with imec was important to this initiative. What effects did it yield?

 

We have a longstanding relationship with imec going back to 2002. In the area of sustainability, imec launched a program called Sustainable Semiconductor Technologies and Systems (SSTS) in 2022.

In the past, development proceeded in response to feedback and requests from customers using our equipment. With SSTS, however, development is focused on meeting certain pre-defined requirements.

In this case, we developed a coater/developer that uses photocrosslinking, and the chemical manufacturer developed a photocrosslinked base film. However, having developed this system, it was essential to verify and understand its applicability within the actual semiconductor manufacturing process. This is where we have been working with imec.

In the case of this photocrosslinking technology, we sent our DT-3000 coater/developer to imec, and they verified its reliability and quantified its performance.

 

Please tell us about the effects achieved with the photocrosslinking technology.
 

The initial evaluations performed by imec found that the use of photocrosslinking technology instead of conventional annealing reduced the power required by 65% to 85% and achieved a 24% reduction in Scope 2 greenhouse gas emissions (CO₂ equivalent).

Furthermore, photocrosslinking the photoresist takes less time than annealing, helping increase the number of wafers processed per hour .

Initial quality evaluations of the photocrosslinked photoresist film have shown no problems, and imec is now going to conduct evaluations of wafer performance using an integrated module.

The EU Life Cycle Analysis (LCA) evaluation methodology applied to reach these results encompass overall environmental impact, so I think it is safe to say that the photocrosslinking technology is highly efficient. In this initiative, SCREEN Semiconductor Solutions—the equipment manufacturer—along with the chemical manufacturer and imec all worked together to utilize the SSTS program.

This room-temperature light irradiation technology is a great option for companies that want to reduce energy consumption, as well as companies facing issues with substrate deformation and film cracking due to film deposition in high-temperature processes. I hope they will give it a try.

 

 

Five-year agreement signed with imec—developing new solutions with a long-term perspective

What are you working on next?

 

In March 2025, we signed a new Strategic Partner Agreement with imec.

Reflecting our mutual emphasis on maintaining a long-term relationship, this time we entered into a long-term contract spanning five years. We have already set concrete goals for the first two years, and we will discuss what to do in the latter three years in light of how things unfold going forward. We plan to work closely together, meeting monthly and making frequent site visits.

A meeting at imec

 

Going forward, as regulations tighten, materials that we have been able to use until now may become unavailable. As we keep abreast of regulatory changes, working in collaboration may lead to new technologies and breakthroughs useful for dealing with new regulations. Using this framework, I hope to continue to provide sustainable solutions.

Talented individuals of diverse nationalities and specialties are working with us on the project. Although we have sometimes encountered differences in thinking or approaches, we have set up online meetings as well as numerous offline, in-person meetings to deepen mutual understanding and facilitate development, and I feel we have achieved a good synergy.

 

Lastly, could you speak about the outlook for SCREEN Semiconductor Solutions going forward?

 

Rather than viewing the development of sustainable technologies negatively, as a requirement forced on us by social trends or governments, we see it as a business opportunity.

Although this technology was developed for cutting-edge processes, we hope to expand it to legacy nodes, as well. We will continue to collaborate with companies in other fields, such as material manufacturers, to create new technologies and value and thereby help protect the environment and make a difference in society.