Alpha HPA (ASX:A4N) said a Japanese customer manufacturing thermal fillers for the semiconductor sector has upgraded an existing letter of intent (LOI) to 360 tonnes per annum (tpa) from 100 tpa for one of its high-purity materials, according to a Wednesday Australian bourse filing.

The company said two other high-purity alumina materials are in the final qualification stage, with similar volume upgrades expected in the coming months, and expects this customer to reach about 720 tpa of total product demand, the filing added.

The company added that a second Japanese customer specializing in semiconductor ceramics and thermal fillers has upgraded its LOI to 96 tpa from 60 tpa, with Alpha expecting this customer's demand to surpass 700 tpa as multiple high-purity powder products complete qualification.

Total LOI coverage for qualified product volumes has reached 6,900 tpa, excluding the projected customer volumes, the filing added.

The company said demand has increased in sectors including synthetic sapphire and water treatment, and that it is making progress toward increasing stage 1 production capacity to meet calendar 2026 and calendar 2027 demand from key customers.

The company's shares rose 2% in recent Wednesday trade.