KERI develops tailored pulsed power modulator for bias in semiconductor processing

A research team led by Dr. Jang Sung-roc at the Electrophysics Research Center of the Korea Electrotechnology Research Institute (KERI) has developed a ‘tailored pulsed power modulator for bias’, which can be applied in ultra-precision semiconductor processing.

A bias device applies a force(voltage) that pulls ions within plasma to make them collide forcefully with a semiconductor wafer. This enables processes such as etching(cutting the surface), cleaning(removing contaminants), and deposition(pressing thin films uniformly and firmly). While radio-frequency(RF) power supplies are widely used in the industry to apply this bias voltage, their simple, alternating waveforms limit the precision required for advanced semiconductor microfabrication.

Against this backdrop, ‘a pulsed power supply’, which can deliver a tailored bias force even for demanding and complex processes, is gaining attention. A pulsed power supply stores energy at low power over a long period and then discharges it instantaneously at high power. By precisely controlling the strength of these pulses, semiconductor substrates can be etched as narrowly and deeply as desired, making the technology applicable across various fabrication processes.

However, conventional pulsed power supplies suffer significant power loss during instantaneous high-power discharge. For tailored bias applications, in particular, the technical requirements are even more demanding, since pulses reaching several kilovolts must be stably controlled within an extremely short duration of 2.5 ㎲(1/250,000th of a second) and discharged at a high frequency of 400kHz(400,000 times per second).

KERI, with over a decade of experience in developing a variety of technologies in the field of pulsed power, recognized this challenge and launched an initiative to achieve domestic production of pulsed power supplies for semiconductor bias processes. Dr. Jang Sung-roc’s team made a breakthrough by becoming the first in the world to introduce ‘soft switching,’ a technique that reduces power loss during pulse discharge. This technique is designed to switch the device at points where the voltage(V) or current(I) is near zero, reducing stress on the device and cutting power loss by over 78%. This innovation also addresses heat generation issues, contributing to smaller power supplies, higher power density (output per volume), and longer lifespan.

The research team further expanded the technology’s applicability by introducing a tailored pulsed power supply that incorporates both methods: ▲ ‘ramped’ mode that uses inclined waveforms for compact and precise processing, and ▲ ‘stepped’ mode that generates the various shapes required for semiconductor fabrication. This advancement makes the technology suitable not only for semiconductors but also for other industries such as environmental engineering, defense, and healthcare where pulsed power is essential.

The technology was validated inside a semiconductor process chamber through collaboration with the Plasma E.I. Convergence Research Center of the Korea Institute of Fusion Energy, which has been conducting research with the support of the Convergence Research Center of the National Research Council of Science & Technology. During the demonstration, the team observed the unique waveforms created by the tailored pulsed power supply, confirming its applicability. Building on this success, KERI plans to lay the groundwork for commercialization by applying the tailored pulsed power supply to actual etching and cleaning equipment in joint research with the Korea Institute of Machinery & Materials and the Korea Institute of Fusion Energy.

Dr. Jang stated, “Process innovation using tailored pulsed power will greatly enhance semiconductor performance, making the electronic devices we use smaller, faster, and longer-lasting.” He added, “Our technology will be a major asset for companies struggling to adopt next-generation processes due to a lack of pulsed power solutions.”

Having secured patents for this achievement, KERI plans to drive commercialization and broaden the application of its tailored pulsed power technology in next-generation industrial processes through industry-academia-research collaboration and technology transfer.

For reference, KERI is a government-funded research institute under the National Research Council of Science & Technology of the Ministry of Science and ICT. The Electrophysics Research Center at KERI is actively working to generate plasma for sterilization, decomposition, disinfection, and cleaning using pulsed power devices, and to apply this technology across diverse industries. The center has also attracted global attention for its major achievements, such as developing ‘semiconductor-based high-power switches’ to effectively control pulsed power and successfully applying them to accelerators and DC circuit breakers. <KERI>