Multi-Physics Modeling of Electrochemical Deposition

Justin Kauffman,Eric Paterson,John Gilbert

doi:10.3390/fluids5040240

Abstract

Electrochemical deposition (ECD) is a common method used in the field of microelectronics to grow metallic coatings on an electrode. The deposition process occurs in an electrolyte bath where dissolved ions of the depositing material are suspended in an acid while an electric current is applied to the electrodes. The proposed computational model uses the finite volume method and the finite area method to predict copper growth on the plating surface without the use of a level set method or deforming mesh because the amount of copper layer growth is not expected to impact the fluid motion. The finite area method enables the solver to track the growth of the copper layer and uses the current density as a forcing function for an electric potential field on the plating surface. The current density at the electrolyte-plating surface interface is converged within each PISO (Pressure Implicit with Splitting Operator) loop iteration and incorporates the variance of the electrical resistance that occurs via the growth of the copper layer. This paper demonstrates the application of the finite area method for an ECD problem and additionally incorporates coupling between fluid mechanics, ionic diffusion, and electrochemistry.

Highlights

Electrochemical deposition (ECD) is an integral process in the fabrication of semiconductor devices
ECD is not the only deposition technique used for growing copper layers in semiconductor devices, but it is a popular and inexpensive method, since it does not require a vacuum or heating of the system [3]
It can be observed that there are slight changes in the surface electric potential at the corner of the plating surface, and the bulk electric potential is decreased. This change in electric potential at the interface of the plating surface leads to a decrease of the current density over time, but overall the current density at this interface is larger, see Figure 9a

Summary

Introduction

Electrochemical deposition (ECD) is an integral process in the fabrication of semiconductor devices. ECD is not the only deposition technique used for growing copper layers in semiconductor devices, but it is a popular and inexpensive method, since it does not require a vacuum or heating of the system [3]. This method is able to deposit high-aspect ratio features with a high degree of precision. Positive ions are shed from the anode and added to the electrolyte. Diffusion and migration of ions occurs in the electrolyte

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