Formation and Wet Removal of Organic and Titanium-Containing Residues on Patterned TiN/Porous Low-k Structure. (19th October 2018)

• Record Type: Journal Article
• Authors: Le, Q. T.; Kesters, E.; Holsteyns, F.
• Is Part Of: ECS journal of solid state science and technology. Volume 7:Number 11(2018)
• Page Start: P602
• Page End: P607
• Publication Date: 2018-10-19
• Subjects: Cleaning -- Dielectrics - Low-k -- Surface Science -- ATR-FTIR -- post-etch residue removal -- Residue growth; Solid state chemistry -- Periodicals; Electronics -- Materials -- Periodicals; Electrochemistry -- Periodicals; 541.0421
• DOI: 10.1149/2.0041811jss
• Languages: English
• ISSNs: 2162-8777

Abstract

Abstract : The formation of the residues after patterning of a patterned metal hard mask/dielectric stack was characterized using surface-sensitive methods (attenuated total reflection-Fourier transform infrared spectroscopy and angle-resolved X-ray photoelectron spectroscopy) and scanning electron microscopy. The effect of a reducing plasma post-etch treatment (PET), aging, and moisture on the evolution of the residues was investigated. Both polymer-based (CFx) and metal-containing (TiFx) residues were identified on the exposed surface of the stack. Without the PET, the XPS data collected at different take-off angles suggested that the metal-containing residues were covered by a thin layer of polymer-based residues. The metal-containing residues were found to continue to evolve as a function of aging time if the layer of polymer-based residues was removed by the PET, making the metal hard mask in direct contact with cleanroom air. Exposing the MHM/dielectric stack to a 100% humidity environment did not induce further growing of the TiFx residues. Despite the PET only had limited removal of the TiFx-based residues, it was efficient in removing the polymer-based CFx residues, which in turn led to a better cleaning efficiency after the subsequent wet clean. The results in this study also confirmed that diluted HF dissolved TiFx-type residues and had no CFx removal capability. Although only two chemicals are shown as examples for post-etch residue removal, the type of test structure and methodology shown in this study can be applied for investigation and optimization of any other chemical mixture candidates for cleaning purpose.