Articles you may be interested inResidue growth on metallic-hard mask after dielectric etching in fluorocarbon-based plasmas. I. Mechanisms

Diffusion and eutectic bonding are gaining broad acceptance in 3D integration and packaging. Many bonding schemes are based on copper because this material is used extensively in FEOL, has a well developed CMP history and high yield TSV's have been proven. One of the issues for low resistivity interconnects and high bonding yield is the surface cleaning methods used to remove copper oxidation. This paper will present the results of studies using DuPont EKC products for copper surface preparation prior to wafer bonding.

No abstract

This paper will examine the combined use of both permanent and temporary high-temperature polyimide adhesives used to avoid thin wafer handling. While 3D-TSV technology can improve functionality and performance, adoption of this technology has been delayed by cracking as well as unwanted wafer bowing. This presentation shows means by which a photo-lithographic polyimide adhesive is used in a temporary bonding scheme to eliminate intermediate-stage thinned wafer handling.

Plasma dry etching processes are commonly used to fabricate vertical sidewall trenches and vias for copper (Cu) / lowk dual damascene devices. Small amounts of polymer are intentionally left on the sidewalls of trenches and vias during the dry etching process in order to achieve a vertical profile and to protect the low-k materials under the etching mask. Other particulate etch residues (such as mixtures of copper oxide (Cu x O y ) with polymers) can be seen in the bottom of the vias. As technology nodes advance to 45nm and beyond, IC companies are investigating the use of a metal hardmask such as TiN in order to gain better etching selectivity to the low-k materials during the dry etching process. In order to obtain reliable, low-resistance interconnects that can be used to manufacture advanced IC devices, the polymers on the sidewalls and the particulate residues at the via bottoms must be removed prior to the next process step. In this paper we report a recently developed wet cleaning approach to remove the metal hardmask etch residues while maintaining high selectivity to the copper and low-k film(s). This was demonstrated at the 45nm technology node for porous low-k, as well as 65nm for non-porous low-k materials through controlled modification of the formulations. The cleaning mechanism of the etch residues is discussed.