Ralf Wagenfuehr on Developing Rehm Thermal Systems' RDS Semico Oven

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Ralf Wagenfuehr of Rehm Thermal Systems describes Rehm’s new oven—the RDS Semico—and gives an in-depth analysis about how it was designed specifically with the semiconductor industry in mind. Ralf also discusses the semiconductor industry as a whole and outlines the company’s desire to gain market share in Taiwan and Korea in the upcoming year.

Barry Matties: We’re inside the Rehm booth at the productronica show in China. Ralf, what’s your title?

Wagenfuehr: I’m a plant manager, and I’m in charge of supervising all of the technology and manufacturing in our Dongguan plant. We are linked directly to our CTO in Germany and our German technology department.

Matties: Can you tell me about your new piece of equipment?

Ralf Wagenfuehr: We call it RDS Semico. The name shows what industry this is designed for, the semiconductor industry, and we are focusing on the packaging process. The heart of this equipment is a normal reflow oven, but it should fit into the cleanroom environment as well. It’s more for the precision and antivibration requirements of the semiconductor industry.

We’re more careful than our competitors. Two large American brands have already had equipment for years. We started in 2013–2014, and then we developed this machine over three years for this industry. Last year, we also exhibited the RDS Semico, but it was not yet fully recognized in the market. We sold a few systems to ensure the product was mature in the final version for the semiconductor industry.

What we’re doing is different from the normal reflow. We came back to the beginning of Rehm and have a full stainless steel chamber because many people are thinking about cleanroom. The machine is class 1000, which means you have much fewer particles in the ISO class 1000, which is required for the semiconductor packaging process.

All of our competitors put isolation inside of the chamber, and if you measure one meter away from the RDS Semico, it’s fit for cleanrooms and fulfills the requirement. But with isolation inside of the chamber, you never know what is inside of the process. Everybody knows isolation has particles in processes where they should not be, but that’s where their product finally ended up. Instead, we went back to our early years and have our full inner stainless steel chamber with isolation on the outside.

For this process, we can guarantee two advantages. First, we have no particles inside of the room since it’s 100% stainless steel. The surface inside is totally clean, and stainless steel is one of the highest materials, so it fits the industry well. Second, the RDS Semico is for nitrogen. If you have isolation inside, when you switch on the machine, there are air pockets inside of the isolation. I’ve been with Rehm for over 20 years at Rehm already, and I remember that the reflow standard used to be 50 PPM, and for the semiconductor industry, it was 20–50 PPM.

So, we chose to come back to this design. If you have isolation inside, you need to insert much more nitrogen to remove the oxygen to reach the standard levels. For us, the advantage of using less nitrogen is we can reach the value faster, and we have a more stable process. Combining this with our latest technology of the Pyrolysis system, we—along with one of the biggest Taiwanese SMT manufacturers—have proven that we can catch more than two tons of flux within two months. People understand that in the semiconductor industry, you will never have this, even in one year.


But with this Pyrolysis equipment, we are maintenance free up to one year or longer in this kind of environment. The RDS Semico does not collect dirt; we eliminate it by cracking it in a Pyrolysis system. Pyrolysis is a chemical process that happens above 460°C, and we make it by 480–500°C. We have a very clean process environment. Maintenance in this industry for cleanrooms is very complicated, so this is a huge benefit.

Further, we have also a vibration-free mesh belt. Here, we’re exhibiting a combination of a pin chain and mesh belt product. Customers can choose to use the PCB or the mesh belt, whereby in our targeted semiconductor industry, 80% may use only a mesh belt. But we are exhibiting our total solution, so the customer can choose whatever competence to put on the pins or mesh belt.

We’re also doing vibration measurement during the process. We have an online vibration measurement system to check all of the vibrations during the process. You can set your alarm values and recognize if there is any disturbance in the process not only from the machine but from your building or other environmental issues.

The mesh belt is a special design and took some time to make it nearly perfect. We have less friction and a very steady driving system, which makes it vibration free. For the process, we have two analyzers. One switches on the whole process room and monitors it from the inlet to the cooling zone in intervals. The second analyzer is steady because we were thinking also about the manufacturing execution system (MES) and the future of software integration in this industry. If we keep switching the analyzer as our competitors do, it’s not a steady value. MES software should have allocated value, and that is very difficult if you keep on switching; that value will change.

We know the industry well now and we have taken time as a German company to make it perfectly engineered. It took some time to do that, but I think we have a better product. We have already distributed some in Taiwan as well in China, and the feedback is very good.



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