Densification of polycrystalline alumina with dense dislocation arrays via stainless steel sealed powder metallurgy hot isostatic press

초록

Aluminum oxide (alumina, Al2O3) is one of the most widely used ceramic materials owing to its excellent dielectric, chemical resistance, and low cost. In contemporary semiconductor fabrication processing, in partic-ular, Al2O3 plays a key role in high-value processing components, such as an electrostatic chuck. Here, we report for the first time a novel densifying technique for Al2O3 that can be referred to as the powder metallurgy hot isostatic press (PM-HIP) process. Unlike the conventional HIP process, our PM-HIP process can directly convert Al2O3 powders into fully densified ceramics via a one-step process. More importantly, during the PM-HIP pro-cess, thermomechanical energy can easily be transferred to each of the particles simultaneously, which facilitates the sinter process (i.e., necking and diffusion) and the clipping of lattice planes. As a result, highly dense dislocation arrays are embedded within the entire volume of the sintered body. This correlates with unique material properties-processing relationships in the Al2O3 ceramics sintered via PM-HIP. The Al2O3 ceramics sintered by PM-HIP exhibited unique mechanical and electrical properties, highlighting its potential for use in electrostatic chucks.

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