[News] Tsinghua University Breaks Ground on EUV Photoresist in China’s Semiconductor Push

As SiCarrier advances chipmaking tools for 5nm production amid China’s semiconductor self-reliance push, Tsinghua University has reportedly achieved a breakthrough in EUV lithography materials. Researchers have developed a new polytellurium oxane-based photoresist, opening up fresh design strategies for next-gen semiconductor materials, as per Tsinghua and Mydrivers.

As Tsinghua notes, EUV lithography using a 13.5nm wavelength has become crucial for chip production at 7nm and below. However, the technology still faces a few challenges—EUV light sources suffer from high reflection losses and low brightness, placing greater demands on photoresists to improve absorption efficiency, reaction mechanisms, and defect control, according to MyDrivers.

According to Tsinghua, ideal EUV photoresists should have four key traits: strong EUV absorption, efficient energy use, molecular uniformity, and minimal building blocks for higher sensitivity. The university’s new photoresist reportedly checks all the boxes.

As Tsinghua explains, the research team directly introduced tellurium (Te), a high EUV-absorbing element, into the polymer backbone through Te–O (Oxygen) bonds. Tellurium absorbs EUV light much more effectively than the lighter elements or metals like Zn, Zr, Hf, and Sn commonly used in traditional photoresists, significantly improving EUV absorption efficiency, Tsinghua says.

In addition, Tsingua points out that the Te–O bond in the polymer is relatively weak, so when exposed to EUV light, it breaks easily, allowing for very sensitive pattern development.

The research, titled “Polytelluoxane as the ideal formulation for EUV photoresist,” was published in Science Advances on July 16.

If proven practical, this development could be a major breakthrough for China’s chip industry. JRJ.com previously reported that China’s domestic production of KrF/ArF photoresists is still below 5%, while EUV photoresists rely on imports. To tackle this, China’s “National Integrated Circuit Industry Investment Fund Phase III Plan” targets photoresists and key semiconductor materials, allocating over 50 billion yuan to boost research and industrialization, the report adds.

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