Investigation of Copper Etching with a Ferric Nitrate Solution

Area of Science:

• Materials Science
• Electrochemistry
• Surface Chemistry

Background:

• Copper's low electrical resistivity makes it vital for integrated circuits and microelectronics.
• Effective etching techniques are crucial for fabricating microelectronic devices.

Purpose of the Study:

• To investigate copper etching methods, focusing on ferric nitrate-based solutions.
• To evaluate the inhibition efficiency and surface quality achieved with ferric nitrate and benzotriazole.

Main Methods:

• Potentiodynamic polarization tests were conducted using benzotriazole as an inhibitor.
• Fourier transform infrared analysis confirmed benzotriazole adsorption on copper surfaces.
• Atomic force microscopy characterized the surface roughness of etched copper films.

Main Results:

• Ferric nitrate demonstrated higher inhibition efficiency than conventional etchants.
• Benzotriazole showed greater adsorption on copper in ferric nitrate solutions compared to ferric chloride and cupric chloride.
• Copper films etched in ferric nitrate exhibited improved surface quality with significantly lower roughness.

Conclusions:

• Ferric nitrate solutions with benzotriazole are effective for copper etching in microelectronics.
• This method yields superior surface quality, crucial for advanced semiconductor manufacturing.
• The enhanced adsorption of benzotriazole contributes to the improved etching performance.