Cu electroplating chemistry and process enabling rapid TSV filling with long bath life

Through-silicon via (TSV) filling with electroplated Cu with short plating times and long bath life remains a challenge within the semiconductor and electronic packaging industries. TSVs are the primary enabler for advanced 3D architectures such as hybrid memory cubes, wide IO DDR memory, as well as chip interconnections through interposers. The TSV needs to be completely filled with void-free Cu for high reliability. Organic additives are used to achieve a bottom-up, superconformal filling profile, required for void-free filling in high aspect ratio vias. The development and selection of the proper organic additives, optimized plating process, and implementation of advanced bath control techniques enable short TSV electroplating times, while also allowing for robust operation and high bath stability. Dow's INTERLINK™ 9200 Cu TSV plating bath with the Applied Materials TSPlus plating system allows 10×100 μm vias to be filled in less than 1 hour and 5×50 μm vias filled in under 20 minutes while having a bath life greater than 40 A hr L-1 in continuous operation. This combination also exhibits low overburden for stress management, CMP cost reductions, and high reliability.

Impact of Bath Stability on Electroplated Cu for TSVs in a Controlled Environment

This study addresses the impact of bath stability on electroplated copper for through-silicon via (TSV) in a controlled manufacturing environment. Microstructure, impurities, and other properties of the copper produced were characterized using an array of techniques, including electron backscatter diffraction analysis, focused ion beam–secondary electron microscope, and time of flight–secondary ion mass spectrometry. Chemical analyses of the plating baths throughout their lives indicates that the process can be controlled. Overall, a manufacturing process was demonstrated that can create high-quality, TSV Cu fill interconnects for 3-D IC over the life of the bath. The process has enabled further development work at State University of New York Polytechnic Institute for downstream processes such as chemical mechanical planarization and Cu-Cu bonding.

Impact of Bath Stability on Electroplated Cu for Through-Silicon-Vias (TSV) in a Controlled Manufacturing Environment

This study addresses the impact of bath stability on electroplated copper for through silicon via (TSV) in a controlled manufacturing environment. Microstructure, impurities and other properties of the copper produced were characterized using an array of techniques, including Electron Backscatter Diffraction Analysis (EBSD), Focused Ion Beam – Secondary Electron Microscope (FIB-SEM) and Time of Flight - Secondary Ion Mass Spectrometry (ToF-SIMS). Chemical analyses of the plating baths throughout their lives indicates that the process can be controlled. Overall, a manufacturing process was demonstrated that can create high quality TSV Cu fill interconnects for 3D IC over the life of the bath. The process has enabled further development work at State University of New York Polytechnic Institute (SUNY Poly) for downstream processes such as chemical mechanical planarization (CMP) and Cu-Cu bonding.

Effect on Electroless Nickel Coating on Magnesium Alloy by Nickel Electroless Plating Parameters

Electroless nickel plating on magnesium alloy was studied when NiSO4as the main salt in the solution. The influence of the composition of the solution and process parameters on the coating appearance, the plating rate and bath stability was studied too. As a result, the optimum conditions of electroless nickel are: The main salt and reducing agent molar ratio between 0.3 and 0.45, mixed complexion agents was used, temperature 90°C, pH value 6.5.

Reconditioning of Electroless Nickel Plating Bath on Magnesium Alloys

The reconditioning operation of electroless nickel (EN) plating was studied and the influence of aging on the deposition speed, phosphorous content and stability of the operating solution was analyzed. The results showed that aging of the EN bath caused a dramatic declining of the deposition speed and the bath stability, while a slow increasing in phosphorous content of the deposit. Fluoride of NaF and NiF2would precipitate from the bath due to the accumulation of sodium and fluorine ions during the replenishment. The sediment of NaF and NiF2had a detrimental effect on the EN process and would deteriorate the protection of EN plating.