Development of the Environmental Friendly Non-Aqueous Tape Casting Process for High-Quality Si₃N₄Ceramic Substrates

Abstract

A cheap and environmental friendly non-aqueous tape casting process for preparing high quality Si3N4 ceramic substrates was explored. A ternary solvent mixture of ethanol, ethyl acetate and butyl acetate-based formula was developed by using castor oil, polyvinyl butyral and dibutyl phthalate as the dispersant, binder and plasticizer, respectively. The influence of dispersant content, binder content and solid loading on the rheological properties of Si3N4 slurries was firstly investigated. It was found that the optimized formulation for dispersant, binder and solid loading was 1.6 wt%, 12 wt% and 51 wt%, respectively. The flat, flexible and uniform green tapes with a thickness of 400–500 μm and high-quality including high bulk density, uniform pore distribution and low porosity were obtained. After drying and debinding, the green sheets were sintered at 1900 °C for 2 h, where Si3N4 ceramics with a thermal conductivity being 85.79 W·m−1·K−1 can be achieved. The sintered samples were one of the most attractive substrate materials for high power electronics applications.

Fabrication of Si3N4 ceramics substrates with high thermal conductivity by tape casting and gas pressure sintering

“…The flexural strength of the sample was 735 ± 24 MPa and fracture toughness was 7.17 MPa m 1/2 , satisfying the requirements for the mechanical properties of Si 3 N 4 ceramic substrates in industrial production. The sintered sample had a thermal conductivity of 100.5 W m −1 K −1 , which is higher than that of Si 3 N 4 ceramic substrates prepared by the current tape casting method, [38][39][40] as shown in Figure 8. There are two main reasons for the higher thermal conductivity.…”

Production of Translucent Alumina Ceramics by Tape Casting

“…The process involves casting a specially formulated slurry onto a stationary or moving surface. The slurry involves ceramic powder in solvent having other additives like binders, dispersants, and plasticizers (Hou et al, 2019;Zhao et al, 2020). Resulting green body has better uniformity compared to traditional dry pressing since it is formed by in situ consolidation of polymers (Jurkow et al, 2011;Liu et al, 2012;Ba et al, 2013;Naebe & Shirvanimoghaddam, 2016;Vozdecky et al, 2010;Feng et al, 2020).…”