Mitsubishi Chemical Corporation is commercializing a new negative thermal expansion filler designed to tackle one of the growing challenges in advanced semiconductor packaging: warpage caused by heat.

 

The new material, branded “M-Filleris NTE,” contracts when heated, helping reduce thermal expansion in semiconductor packaging materials. Mitsubishi Chemical plans to begin selling pilot products by the end of fiscal 2026, followed by customer evaluations and certifications, with mass-production sales targeted for the second half of fiscal 2027.

 

The move comes as demand for more powerful chips accelerates alongside the expansion of AI servers and high-performance computing (HPC).

 

Advanced packaging approaches, including chiplet and 3D stacking technologies, are packing more chips into smaller spaces. That higher density is driving greater heat generation and making thermal management—and the resulting dimensional changes in semiconductor packages—an increasingly important issue.

 

Epoxy resins and silica fillers are widely used to control thermal expansion, but manufacturers are increasingly reaching the practical limits of how much conventional filler can be incorporated into packaging materials.

 

Mitsubishi Chemical says its new filler addresses that challenge by contracting as temperatures rise, offsetting the expansion of surrounding materials.

 

The company developed the material using its inorganic material design technology and says it overcomes several limitations associated with conventional negative thermal expansion materials, including narrow operating temperature ranges, irregular shapes, high specific gravity and high water absorption.

 

According to Mitsubishi Chemical, M-Filleris NTE offers negative thermal expansion characteristics from room temperature to 400°C, while its spherical particles provide strong fluidity and dispersibility when mixed into epoxy resins and other materials.

 

The material also features low alpha-particle emissions through impurity control, a property aimed at reducing soft errors in semiconductor applications. Its specific gravity and water absorption are comparable to those of conventional semiconductor-grade silica fillers.

 

Potential applications include semiconductor encapsulants, underfill materials and build-up film materials, expanding the range of packaging processes in which the new filler could be used.

 

Mitsubishi Chemical also plans to leverage its existing epoxy resin business to supply the filler not only as a standalone material but also as masterbatches premixed with epoxy resin and other components. The company says this approach could help customers shorten material design and development timelines.

 

The company plans to expand the M-Filleris lineup with other functional fillers offering capabilities such as heat dissipation and electrical properties.

 

Mitsubishi Chemical is positioning the launch as part of its push into a semiconductor materials market expected to benefit from continued growth in AI and data-center demand.