Low-Temperature Aluminum-Aluminum Wafer Bonding. (24th August 2016)

• Record Type: Journal Article
• Authors: Rebhan, Bernhard; Hinterreiter, Andreas; Malik, Nishant; Schjølberg-Henriksen, Kari; Dragoi, Viorel; Hingerl, Kurt
• Is Part Of: ECS transactions. Volume 75:Number 9(2016)
• Page Start: 15
• Page End: 24
• Publication Date: 2016-08-24
• Subjects: Electrochemistry -- Periodicals; Electrochemistry; Periodicals; Electronic journals; Electronic journal; 541.37
• DOI: 10.1149/07509.0015ecst
• Languages: English
• ISSNs: 1938-5862

Abstract

Abstract : Aluminum-aluminum thermo-compression wafer bonding is becoming increasingly important in the production of microelectromechanical systems (MEMS) devices. As the chemically highly stable aluminum oxide layer acts as a diffusion barrier between the two aluminum metallization layers, up to now the process has required bonding temperatures of 300°C or more. By using the EVG ® 580 ComBond ® system, in which a surface treatment and subsequent wafer bonding are both performed in a high vacuum cluster, for the first time successful Al-Al wafer bonding was possible at a temperature of 100°C. The bonded interfaces of blank Al wafers and Al wafers with patterned frames were characterized using C-mode scanning acoustic microscopy (C-SAM) and transmission electron microscopy (TEM) as well as dicing yield and pull tests representative for the bonding strength. The investigations revealed areas of oxide-free, atomic contact at the Al-Al bonded interface.