負熱膨張性微粒子による電子デバイスのサーマル・マネジメント

抄録

Rapid advances in modern technology have led to increasing demands for control of thermal expansion. Recently, it has become necessary to control thermal expansion in a local region at the micrometer level, especially in the field of electronic devices. To meet this demand, attempts have been made to produce micrometer or submicrometer scale fine particles showing negative thermal expansion (NTE). Here, recent studies on spry-dry synthesis of β-Cu_1.8Zn_0.2V₂O₇ ceramic particles are reviewed. This class of vanadates shows large NTE linear to temperature over a wide temperature range. This NTE originates from the microstructures consisting of voids and anisotropic thermal deformation of crystal grains in a ceramic particle. By reducing the size of the microstructures that produce NTE, large NTE equivalent to bulk was realized even for ceramic particles of about 2 μm sizes. Comparison with the conventional method shows that this method provides the benefit of obtaining fine particles of narrow particle size distribution with a shape close to a sphere. This achievement is expected to pave the way for the use of NTE materials to control thermal expansion of a local region, for example, internal components of advanced electronic devices such as three-dimensional integrated circuit.