Optimization of Wet Strip for Metal Void Reduction in Trench First Metal Hard Mask Back End of Line Process

Asha Sharma; Bruce Gondeck; Sunil Singh; Teck Jung Tang; Silas Scott; Philippe Helal

doi:10.4028/www.scientific.net/SSP.282.250

Paper Titles

Aluminum Cleaning on Single Wafer Tool: A Case Study with Diluted HF
p.226

Atomic Layer Deposition of TiN below 600 K Using N₂H₄
p.232

Process Parameter Control for BEOL TiN Hard Mask Etch-Back
p.238

BEOL Post-Etch Clean Robustness Improvement with Ultra-Diluted Hf for 28nm Node
p.244

Optimization of Wet Strip for Metal Void Reduction in Trench First Metal Hard Mask Back End of Line Process
p.250

Corrosion of Co in BEOL interconnects in dilute HF solution
p.256

Effect of Cleaning Chemistries on Cobalt: Surface Chemistries and Electrical Characterization
p.263

Optimization of Post Etch Cobalt Compatible Clean by pH and Oxidizer
p.268

Developing Integrated Solutions and Wet Cleans to Eliminate Tungsten Contact Attack in Sub 0x nm Nodes
p.273

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Optimization of Wet Strip for Metal Void Reduction in Trench First Metal Hard Mask Back End of Line Process

Abstract:

The purpose of this paper is to study the effects of wet strip clean for metal void reduction in trench first metal hard mask back end of line (BEOL) integration process in 14 nm Technology. A thicker TiN film is becoming important to resolve via-metal short yield and time-dependent dielectric breakdown (TDDB) issues caused by the Litho-Etch-Litho-Etch (LELE) misalignment due to smaller patterning features. This brings the multitude of advanced integration technology need for complete TiN hard mask (HM) removal, post etch residue removal, ultra low-k dielectric (ULK) and Cu stability, interconnect resistance, and continuing high volume manufacturing (HVM) cost challenges together with environmental concerns and the waste handling/treatment cost. At GlobalFoundries, we achieved a wet strip clean process with a 45 % lower cost of ownership (CoO) while maintaining the TiN HM removal rate, baseline critical dimension (CD), normalized defect density (DOI), the ULK and Cu stability, via resistance, and yield.