In the era of booming AI computing power, the performance improvement of chips no longer depends solely on the shrinking of process nodes. The advent of the "post-Moore era" has made advanced packaging a primary pathway for enhancing chip performance. HBM packaging, Chiplet, advanced packaging, and AI server heat dissipation all impose higher requirements on material properties such as thermal conductivity, insulation, purity, particle size, and low alpha-ray emission.
Among these, Low-α spherical alumina is more oriented toward high-end chip packaging materials. Its core role is to reduce the risk of soft errors caused by radioactive impurities in packaging materials, thereby improving the reliability of high-end chips and storage systems. In other words, it is not an ordinary powder, but one of the foundational materials ensuring the reliability of advanced packaging.
The technical challenges of this product lie in reducing the content of radioactive elements uranium (U) and thorium (Th) to the ppb level, while also meeting multiple indicators such as sphericity, magnetic foreign matter content, particle size distribution, thermal conductivity, and volume filling rate. The technological barriers are high, the process is difficult, the validation cycle is extremely long, and customization requirements are stringent.
Globally, Japan's Admatechs is the industry benchmark, dominating more than 90% of the high-end market worldwide. With the surge in HBM packaging demand driven by AI computing power, and the urgent need for self-reliance in the domestic semiconductor industrial chain, the domestic substitution of Low-α spherical alumina is accelerating. The only company in China that has achieved mass production of Low-α spherical alumina has technical specifications comparable to Japanese competitors, breaking the monopoly of Japanese enterprises. Its products have passed certification from first-tier suppliers such as Samsung SDI and Sumitomo Electric, indirectly supplying international customers including SK Hynix and NVIDIA. In 2025, it obtained batch orders from overseas customers, achieving a leading level in commercialization within China.
The independently developed Low-α spherical alumina powder has radioactive element uranium and thorium contents both below 5 ppb, and has passed TSMC's CoWoS certification. The company's 5,000-ton-per-year high-thermal-conductivity spherical alumina production line has been fixed-asset transferred and put into trial production, while customer sample validation is ongoing simultaneously.
The company has completed the expansion of its Low-α product portfolio for high-end chip packaging, and continues to send samples to key customers in Japan and South Korea. For some customers, sample volumes have increased, and sample-level sales have been achieved. At the same time, samples have also been sent for validation to domestic advanced packaging supply chain customers, though mass sales have not yet been realized.
02 CMP Polishing High-Purity Nano-Alumina Abrasives
Chemical mechanical polishing (CMP) is a critical process in chip manufacturing to achieve global planarization uniformity. It runs throughout the entire process flow, from silicon wafers and wafer fabrication to advanced packaging. The performance of the polishing slurry directly determines chip yield, performance, and reliability. High-purity nano-alumina, with its high hardness, stable performance, insolubility in water, and resistance to acids and alkalis, offers excellent removal rates for hard materials such as sapphire and silicon carbide substrates. It has become an important abrasive choice for CMP slurries used on hard materials like sapphire, SiC, and metal interconnects.
As process nodes shrink, the number of CMP steps has increased from over 10 in mature processes to more than 30 in advanced processes, and the types of polishing slurries have expanded from 6–7 to nearly 30. The global CMP slurry market is expected to reach USD 2.6 billion by 2026. In China alone, the combined market size for copper-based and alumina-based polishing slurries in 2026 is projected to exceed RMB 4 billion.
However, high-purity nano-alumina powder for CMP applications poses extremely high technical hurdles: it must simultaneously meet purity ≥ 4N, extremely narrow particle size distribution, good dispersion without agglomeration, and tunable surface zeta potential to suit different pH slurry systems. For a long time, this market has been monopolized by overseas companies.
In recent years, some domestic products have entered validation or small-batch supply stages. But overall, domestic high-purity alumina is still mostly used in mid-to-low-end fields such as phosphors and sapphire substrates. In high-end applications like CMP, there remains a considerable gap between "being able to produce" and "producing well."
03 5N-Grade and Above High-Purity Alumina
5N-grade (99.999%) high-purity alumina is a key raw material for semiconductor packaging substrates, LED substrates, and high-end display panels. Its production relies on low-impurity raw materials, and the deep purification process is complex and costly. Taking the improved Bayer process as an example, when using ordinary industrial raw materials with complex impurity compositions, how to avoid lattice alkali formation in an alkaline environment and how to thoroughly remove alkali attached to and inside the powder surface are both difficult problems that remain to be solved.
In terms of market landscape, the domestic supply of 5N-grade alumina for high-end applications has long been dominated by overseas enterprises-Japan's Sumitomo Chemical (about 40% global market share) and Germany's Sasol (about 25%) form the dominant duopoly. Advancing import substitution of 5N products is an inevitable requirement for high-quality industry development.