Interdiffusion of Cu-Sn system with Ni ultra-thin buffer layer and material analysis of IMC growth mechanism
Journal
2014 9th International Microsystems, Packaging, Assembly and Circuits Technology Conference: Challenges of Change - Shaping the Future, IMPACT 2014 - Proceedings
Pages
37-40
ISBN
9.78148E+12
Date Issued
2014
Author(s)
Fan C.-H.; Chang Y.-J.; Chou Y.-C.; Chen K.-N.
Abstract
In this paper, Ni ultra-thin diffusion buffer layer between Cu/Sn is inserted to suppress the IMC (η-phase) inter-diffusion reaction. We analogy the bonding condition by using single side Cu/Ni buffer layer/Sn structure. The inter-diffusion behaviors and IMC growth are investigated under the same thermal budget of bonding temperature during the heating step. Cu/Sn IMC formation behavior with Ni buffer layer is summarized by the SEM inspection. In the results of different Ni buffer layers (tNi = 0, 50, 100, 150 Å) and thermal durations (0 to 60 sec), Ni buffer layer insertion can effectively reduce Cu/Sn IMC thickness. In addition, rapid growth of ∼1.5 μm Cu/Sn IMC thickness at 250 °C for only 10 sec is discovered. As results, 100 Å Ni buffer layer is necessary to apply as the Cu/Sn system enters the submicron pad bonding interconnects. © 2014 IEEE.
Subjects
Binary alloys; Budget control; Copper alloys; Diffusion; Nickel; Scanning electron microscopy; Tin alloys; Bonding conditions; Bonding temperatures; Growth mechanisms; IMC thickness; Material analysis; Rapid growth; Thermal budget; Ultra-thin; Buffer layers
Publisher
Institute of Electrical and Electronics Engineers Inc.
Type
conference paper