PSPI Shockwave Asahi Kasei Supply Tightens Impacting TSMC and a 12 Billion Yuan Market

Japan’s Asahi Kasei has abruptly tightened its supply of PIMEL-series photo-sensitive polyimide (PSPI), a critical material in advanced semiconductor packaging. The move, which includes a complete halt in liquid PSPI supply, is driven by surging AI chip demand that has rapidly outpaced production capacity.

PSPI is a high-performance material combining photo-reactivity with thermal stability, essential for chip-level processes such as RDL (redistribution layer) insulation and wafer-level protection. Its photo-patternability allows it to streamline complex multi-layer processes like 2P2M and 4P4M. Beyond semiconductors, it also finds roles in OLED display photolithography and aerospace insulation.

Asahi Kasei commands the global PSPI market, alongside peers like Toray, HD Microsystems, Fujifilm, and JSR. Its materials are vital to leading-edge packaging technologies used by giants such as TSMC and Samsung. For instance, TSMC’s CoWoS packaging depends heavily on PSPI, with the material cost per wafer jumping from ¥50–100 to over ¥500.

According to the China Electronic Materials Industry Association (CEMIA), China’s 2023 PSPI market reached 11.93 billion yuan, split between wafer manufacturing (¥7.97 billion) and packaging (¥3.96 billion). With the rise of 2.5D/3D packaging driven by AI workloads, PSPI demand is projected to accelerate.

Domestically, PSPI for displays is in mass production, but semiconductor-grade materials are still mostly in the R&D or trial phase. Key technical hurdles remain in pattern clarity during edge lithography. A few firms have passed initial customer certifications.

Bomi Technology leads in commercialization, with 500 tons capacity, supplying Huawei HiSilicon. In 2024, it won a national R&D grant for 2.5D/3D packaging materials and was acquired by Yanggu Huatai in a ¥1.443 billion deal.

Aisen Co. began PSPI shipments in 2024, working on negative-tone, ultra-sensitive, and low-temperature curing variants. Notably, it landed the first-ever positive PSPI order from a top wafer fab. Its low-temp curing PSPI cures below 230°C, enabled by pc-PAE resin and IMZ catalysts.

Dinglong Co. operates a 1,000-ton PSPI line in Xiantao and supplies PFAS-free formulations to panel makers. Wanrun Co. supplies OLED-grade PSPI to major display clients and has co-invested in a new materials firm with BOE.

Bayi Space, Guofeng New Materials, Guangxin Materials, and others are actively developing, with pilot or validation-stage products. Guofeng recently launched a 1,600-ton PI film line.

As supply disruptions loom, China’s push for domestic alternatives becomes increasingly urgent, especially as advanced packaging becomes a battleground in the AI era.