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Technological development highlights

Innovation for sustainable semiconductor manufacturing—the SCREEN Group’s development of technology to reduce organic wastewater

Semiconductor technologies undergird practically every aspect of modern life. However, the environmental toll of the semiconductor manufacturing progress is a serious challenge. For the semiconductor industry, sustainable development is no longer an option—it is imperative. In particular, during semiconductor production, the treatment of wastewater from cleaning processes has significant direct implications for climate change and chemical pollution.
To address this issue, as a leader in semiconductor production equipment, the SCREEN Group has developed an innovative technology for reducing organic wastewater with the potential to dramatically reduce environmental impact.
*SCREEN presented this technology at UltraFacility 2024,
   an international semiconductor facility conference held in the U.S. city of Phoenix, Arizona.

To learn more about the technology, how it was developed, and the impact of sustainable development on the semiconductor industry, we interviewed three employees of SCREEN Holdings and SCREEN Semiconductor Solutions involved in the technology’s development.

 

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As semiconductor structures grow more complex, organic wastewater treatment is a growing issue

What kind of work do you do at SCREEN, and what do you see as your mission for the development of the new technology?

 

T. U. :

tech-post01-02-min.pngI work at SCREEN Holdings in the R&D of new elemental technologies for semiconductor production processes.
As semiconductor devices get smaller and smaller, we have to use more and more isopropyl alcohol (IPA), an organic solvent, to prevent pattern collapse, inevitably resulting in more organic wastewater. We turned our attention to this wastewater, seeking to develop a technology to separate the IPA from water in order to decrease total wastewater volume. We have now partially established the technology, but there is still a lot of experimental work to do to make it into a usable product. To move it forward, the team is currently engaged in experiment planning and literature-based research, periodically discussing our experimental results and giving feedback to one another.

 

 

S. I. :

tech-post01-03-min.pngM. I. and I work at SCREEN Semiconductor Solutions, a business operating company under SCREEN Holdings that handles semiconductor production equipment development, production, and sales.
As a process engineer, I work to optimize production processes for equipment developed by semiconductor manufacturers or SCREEN’s equipment design divisions. In addition, part of our mission is to develop and commercialize new technologies based on an understanding of client needs, looking toward mass production five to ten years down the line. In this project, I am in charge of taking the fundamental technology developed by T. U.’s team and making it into a practical product.

 

 

 

M. I. :

tech-post01-04-min.pngI specialize in device design, and my work is mainly in design and the creation of environments to enable process engineers to evaluate processes. In this project, I am working on product design related to incorporating the new technology into actual equipment. My mission is to design equipment that will be simultaneously environmentally friendly and economical.

 

 

 

 

 

 

Sustainable development is now an important issue in terms of corporate social responsibility (CSR), as well. Please tell us about the place of sustainable development in the semiconductor industry today.

 

S. I. :

Over the past few years, calls to reduce environmental burden in semiconductor manufacturing have been growing dramatically. Particular attention has focused on reducing the volumes of chemical agents used and of wastewater. The chemical manufacturing and wastewater treatment processes also generate considerable CO2, so this is an important issue in terms of carbon neutrality, as well.

 

M. I. :

An important factor behind this is the growing complexity of semiconductor devices. Cutting-edge devices have extremely elaborate forms, with ultrafine wafer structures. These require more cleaning processes, and cleaning is naturally more difficult. At the same time, protecting the structures on wafers requires the use of more IPA and other volatile organic solvents. As a result, processing wastewater—especially organic wastewater—is a significant issue.

 

Separating IPA from water with a membrane and building a sophisticated simulation model

How did you go about addressing these issues?

 

T. U. :
Conventional distillation facilities consume a great deal of energy and take up a lot of space. So, we wondered if we could instead use membrane separation technology to treat the wastewater directly as it comes out of the equipment. As I mentioned, we sought to develop a technology for efficiently separating and concentrating the mix of IPA and water.

In the cleaning process, IPA essentially flushes away the water that has adhered to the wafer surface, helping speed up drying. However, this results in a great deal of wastewater containing a mix of water and IPA, leading to greater processing costs, both environmental and economic. In this project, we therefore aimed to significantly reduce the final volume of organic wastewater and thereby lessen the environmental impact through the fundamental research and application of technology to efficiently separate IPA from water.

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Could you tell us more about how the technology works?

 

T. U. :
The key was separation using microporous membranes—membranes containing numerous extremely fine holes. A microporous membrane separates the water molecules from the IPA molecules via a molecular sieving effect.
One advantage we had as an equipment manufacturer is the detailed data we had on the amounts and concentrations of wastewater emitted by our equipment. This enabled us to select the membrane and design the system for the most efficient separation.

In addition, we created a highly accurate simulation model, which played an important role in development. At first, the experimental results and simulation results were off by around 20%. Through a process of repeated fine adjustment, such as optimizing the experimental conditions and simulation conditions and refining our temperature management, we have managed to get the margin of error down to just a few percent. Using the simulation when working out the product specifications helped shorten development time.

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Working as a united group to commercialize a groundbreaking new technology

What steps remain to commercialize this technology?

 

M. I. :
The big challenge to creating a product based on the technology is scaling up our lab results to the size required for a production line.

 

T. U. :
To do so, we will need to use the simulation model we created to predict the behavior of a large system so that we can optimize its design. Using simulations, I think we can advance development efficiently by minimizing the trial-and-error process of applying various conditions in prototype units.

 

S. I. :
The practical application of this technology has the potential to significantly reduce environmental impact in semiconductor manufacturing. In the future, it could even lead to the development of a closed system that reuses the separated IPA. This could enable more effective resource use and further reduce environmental impact.

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What would you say is the driving force of the SCREEN Group’s technological development?

 

T. U. :
By working collaboratively and sharing information on a regular basis, we advance development through close cooperation across the Group. I think this framework provides the foundation for innovative technological development.
In this project, the project members at SCREEN Holdings and SCREEN Semiconductor Solutions have regular meetings every week or two to share progress and give feedback. Also, we constantly share information and advice over the phone and chat as we deal with issues that arise in experiments. Although we have separate workplaces, we visit each other to see the prototypes and such, and there is a great deal of face-to-face technological exchange.

 

S. I. :
SCREEN Holdings has strengths in fundamental research and new technology development, while SCREEN Semiconductor Solutions excels at creating products and understanding client needs. The synergistic effect this creates is another driver of technological development.

 

M. I. :
Four years ago, the Group launched an internal rotation system. The system has helped break down walls between group companies and foster a sense of group unity. I also feel that it has been very effective in facilitating the smooth transfer and commercialization of technologies.


 

Innovation for a Sustainable World: Achieving greater prosperity while protecting the environment

What kind of value do you seek to offer for society through technology that contributes to sustainable development?

 

T. U. :
As solution creators, we work to address issues facing society through our business by advancing technological development, always looking a decade forward. The semiconductor industry is evolving rapidly. Finding the kernels of new technologies that will push it further, and by doing so continuously providing technologies that will shape the future of the industry is, I believe, our mission.

 

S. I. :
SCREEN has defined its purpose as “Innovation for a Sustainable World.” The continued evolution of semiconductor devices will be the basis for a wide range of technologies with the potential to enrich our lives, from AI to self-driving vehicles. The SCREEN Group’s cleaning technologies are a vital part of that story. However, unless we take action, the industry will continue to take a growing toll on the environment. By working to push technology forward while also reducing environmental impact, as in this project, I hope to help create a sustainable future.

 

M. I. :
As an equipment designer, my work directly influences the price and power consumption of the equipment we make. Stepping up environmental technologies tends to result in a heftier price tag. However, I think that simply accepting that trade-off as inevitable is no way to make a truly superior product. Creating products that are appealing on both fronts—better for the environment while highly economical—this is our goal. I hope that, as a result of this approach, our clients and other stakeholders will be able to appreciate first-hand the outstanding initiatives we are pursuing at the SCREEN Group.

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