Prevention of Unexpected Oxidation of Metal Layer by Removing Hydrogen Peroxide from Ultrapure Water and Diluted Hydrofluoric Acid

Daisaku Yaon; Masami Murayama; Hikaru Kobayashi; Koji Yamanaka

doi:10.4028/www.scientific.net/SSP.219.221

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Characterization of Cu-BTA Organic Complexes on Cu during Cu CMP and Post Cu Cleaning
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TiN Hard Mask Cleans with SC1 Solutions, for 64nm Pitch BEOL Patterning
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Industrial Challenges of TiN Hard Mask Wet Removal Process for 14nm Technology Node
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TiN Metal Hardmask Residue Removal Formulation Development for Advanced Porous Low-K and Cu Interconnect Application
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Prevention of Unexpected Oxidation of Metal Layer by Removing Hydrogen Peroxide from Ultrapure Water and Diluted Hydrofluoric Acid
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Cost-of-Ownership Comparison of Single-Wafer Processes for Stripping Copper Pillar Bump Photomasks
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The Role of Mass Transfer in Removal of Cross-Linked Sacrificial Layers in 3DI Applications
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Scaling the 3D Bumps Pitch from 20 to 10 μm, Focusing on the Wet Cu Seed Etch Process Development
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Adhesion Improvement through Plasma Surface Treatments on Palladium Surface
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Prevention of Unexpected Oxidation of Metal Layer by Removing Hydrogen Peroxide from Ultrapure Water and Diluted Hydrofluoric Acid

Abstract:

Ultrapure water (UPW) is widely used for rinsing wafers and diluting chemicals in semiconductor manufacturing processes. The quality of UPW is severely controlled, but the generation of hydrogen peroxide (H₂O₂) as a impurity is inevitable due to the ultraviolet irradiation in a UPW production system (Figure 1). In our survey, it is revealed that the concentration of H₂O₂ in UPW reaches to 10~40 μg/L level. Considering the situation, we have developed a palladium-loaded monolithic anion exchange resin (Pd-M) as a catalyst that is able to remove H₂O₂ from UPW down to below 1 μg/L at an extremely high flow rate (space velocity SV = 6,000 h^-1), with no detectable elution of impurities [1, 2]. Furthermore, we have found that the dissolution rate of copper which is easy to be corroded oxidatively in CO₂-dissolved water (CO₂ UPW) [3] can be decreased to one-third by removal of H₂O₂ from CO₂ UPW using Pd-M catalyst [4]. In this study, we present the effects of H₂O₂ removal from UPW and diluted hydrofluoric acid (DHF) on the surfaces of copper, molybdenum and silicon.