AN ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY AND PSEUDO STEADY STATE VOLTAMMETRIC STUDY OF THE CHLORIDE-SUPPRESSOR COMPLEX FORMED ON THE COPPER SURFACE IN PLATING BATHS THAT EXHIBIT SUPERFILLING USED IN THE DUAL DAMASCENE PROCESS DURING THE COPPER METALLIZATION OF SEMICONDUCTORS

Integrated Circuit Manufacturing;Copper Electrochemical Deposition;Materials Science & Engineering

Long, John GardnerSearson, Peter C ;

Johns Hopkins University

关键词: Integrated Circuit Manufacturing;    Copper Electrochemical Deposition;    Materials Science & Engineering;   

Others  :  https://jscholarship.library.jhu.edu/bitstream/handle/1774.2/60533/LONG-DISSERTATION-2015.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: JOHNS HOPKINS DSpace Repository

【 摘 要 】

Copper has become a key material in semiconductors due to its use as the interconnect material in silicon-based integrated circuits.Electrochemical deposition has shown itself to be a very capable technique to deposit copper in small features without leaving voids or holes.However, the electrochemistry of the additives used in the plating bath are less-well understood than they should be. In this work, the behavior of the suppressor is investigated, and shown to have a well-defined potential at which it ceases suppressing copper deposition.Electrochemical impedance spectroscopy is used in conjunction with cyclic voltammetric measurements to show this cessation of suppression is concurrent with the desorption of a complex formed by the suppressor from the copper surface. Pseudo steady-state voltammetry is shown to be a superior technique for determining the critical potential at which the complex desorbs due to its increased sensitivity and lack of requirement for significant analysis of impedance data.This desorption reaction is studied over a range of different bath chemistries and the concentration dependence is determined for various solution additives.From these dependencies, a model is constructed for the likely composition of the suppressor complex that is adsorbed to the copper surface during deposition. In addition, rotating ring-disk experiments are conducted to investigate the role of copper(I) in the presence of a common solution accelerator, SPS.SPS is shown to increase the concentration of the cuprous species, an increase that is shown to be countered by the presence of dissolved oxygen in the solution.This result provides additional evidence for the role in cuprous ions in copper plating.