Electrical characterization of anodic alumina substrate with via-in-pad structure

• Published in: Electronic materials letters Vol. 9; no. Suppl 1; pp. 65 - 70
• Main Author: Kim, Moonjung
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.10.2013; 대한금속·재료학회
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed Matter Physics; Materials Science; Nanotechnology; Nanotechnology and Microengineering; Optical and Electronic Materials; 전자/정보통신공학; S-parameter; power distribution network impedance; via-in-pad structure; DRAM package; aluminum anodization; transmission line
• ISSN: 1738-8090; 2093-6788
• DOI: 10.1007/s13391-013-3180-5

An anodic alumina substrate has been developed as a package substrate for dynamic random access memory devices. Unlike the conventional package substrates commonly made by laminating an epoxy-based core and cladding with copper, this substrate is fabricated using aluminum anodization technology. The anodization process produces a thick aluminum oxide layer on the aluminum substrate to be used as a dielectric layer. Placing copper patterns on the anodic aluminum oxide layer forms a new substrate structure that consists of a layered structure of aluminum, anodic aluminum oxide, and copper. Using selective anodization in the fabrication process, a via structure connecting the top copper layer and bottom aluminum layer is demonstrated. Additionally, by putting vias directly in the bond and ball pads in the substrate design, the via-in-pad structure is applied in this work. These two-layer metal structures and via-in-pad arrangements make routing easier and thus provide more design flexibility. Additionally, this new package substrate has improved the power distribution network impedance given the characteristics of these structures.