Structural influence of nitrogen-containing groups on triphenylmethane-based levelers in super-conformal copper electroplating

Leveler is one of the most important additives for super-conformal copper electroplating, which has been widely applied in the fabrication of nanoscale (or microscale) interconnect features in integrated circuits (ICs) and printed circuit boards (PCBs). Because the structure-property relationship of...

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Bibliographic Details
Published in:Electrochimica acta 2022-01, Vol.401, p.139445, Article 139445
Main Authors: Li, Zhen, Tan, Baizhao, Luo, Jiye, Qin, Jinfeng, Yang, Guannan, Cui, Chengqiang, Pan, Li
Format: Article
Language:English
Subjects:
Additives
Adsorption
Circuit boards
Contact angle
Copper
Copper electroplating
Electroplating
Electroplating additives
Integrated circuits
Levelers
Microvia filling
Nitrogen
Plating
Polyethylene glycol
Steric hindrance
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Summary:Leveler is one of the most important additives for super-conformal copper electroplating, which has been widely applied in the fabrication of nanoscale (or microscale) interconnect features in integrated circuits (ICs) and printed circuit boards (PCBs). Because the structure-property relationship of the leveler is not clear, the development of novel leveler with high microvia filling performance is very time-consuming and challenging. In this study, a series of triphenylmethane-based (TPM-based) molecules with different nitrogen-containing groups have been designed, synthesized, and investigated as novel levelers for super-conformal copper electroplating. Their structure-property relationships are investigated by electrochemical analyses, contact angle measurements, and microvia filling electroplating experiments. It is found that the steric hindrance and the type of the nitrogen-containing groups (tertiary amine or quaternary ammonium with counter anions) in a leveler not only affect its adsorption ratio and strength on the copper interface, but also affect its adsorption preference on different copper crystalline plane. In combination with Cl−, polyethylene glycol (PEG, suppressor), and bis-(3-sulfopropyl) disulfide (SPS, accelerator), all TPM-based levelers show excellent microvia filling performances in copper electroplating and their effective concentrations are related to their antagonistic ability against the accelerator SPS. [Display omitted]
ISSN:0013-4686
1873-3859
DOI:10.1016/j.electacta.2021.139445