Low-temperature rough-surface wafer bonding with aluminum nitride ceramics implemented by capillary and oxidation actions

Shao Ming Nien, Jian Long Ruan, Yang Kuao Kuo, Benjamin Tien Hsi Lee

Research output: Contribution to journalArticlepeer-review

Abstract

Aluminum nitride (AlN) is a ceramic material with excellent dielectric and thermal properties, and it is used in the microelectron and energy fields. Despite polishing, the roughness (rms >10 nm) of AlN wafers fabricated by sintering fails to meet the surface requirements (rms <0.5 nm) for direct wafer bonding. However, rough-surface wafer bonding of paired AlN and AlN can be achieved with the following procedure: (1) rough surfaces are activated by oxygen plasma to introduce strong capillary action, (2) reactions of AlN and bonding species (OH) are promoted by clamping during storage and annealing and (3) low-temperature annealing (<150 °C) joins the two surfaces of AlN/AlN by synthesizing Al2O3 at the bonding interface. TEM and XPS results show that a transition layer exists between bonding surfaces wherein the concentration of nitrogen decreases while that of oxygen significantly increases.

Original languageEnglish
Pages (from-to)8766-8772
Number of pages7
JournalCeramics International
Volume48
Issue number6
DOIs
StatePublished - 15 Mar 2022

Keywords

  • Aluminum nitride
  • Capillary action
  • Plasma activation
  • Wafer bonding

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