Packaging Approach for Integrating 40/45-nm ELK Devices Into Wire Bond and Flip-Chip Packages

Abstract

There is a rapid transition in the semiconductor packaging industry of devices moving toward 40/45-nm extreme low k (ELK) from the development phase into mainstream semiconductor assembly manufacturing. The drive to achieve adoption without major changes to process and equipment infrastructure while meeting the superior yield necessary is high. The main goal of this paper is to share learning's and provide solutions for integration and qualifications of 40/45-nm ELK devices into flip-chip (FC) and wire-bond (WB) package technology. The scope of this paper covers the fine-pitch ball grid array for the WB packages and FC chip-scale package for the FC Devices. The main challenge and focus point for WB 45/40-nm interconnects is on the first bond process. This paper will share some detailed analysis on the following. 1) Characterization for 45 nm ELK ultrafine-pitch. 2) Key factors for good Au ball bond integrity. 3) Recommendations for achieving the required levels of reliability for 45-nm Cu ELK. The challenge of FC Technology today has been changing at a faster rate and more and more adoption has been made from the conventional eutectic solder bumps or high lead solder bumps toward the lead free solder bump mainly due to the Green initiatives. This paper will share analysis on the following areas. 1) Thermo-mechanical simulation on key input factors and its correlation to actual evaluations. 2) Integration of Pb Free ELK bumps with 40-nm ELK technology are various critical processes. 3) Moldable underfill technology for Pb Free + ELK devices. In addition, critical process control is also required at the wafer level process of wafer thinning and dicing, including the need of Laser Grooving will also be covered.