Characterization and Analysis of Metal Adhesion to Parylene Polymer Substrate Using Scotch Tape Test for Peripheral...

Area of Science:

• Biomedical Engineering
• Materials Science
• Neurotechnology

Background:

• Implantable neural probes require robust metal-electrode adhesion to parylene substrates.
• Delamination of metal layers during fabrication is a significant challenge.
• CF4 plasma treatment is explored as a method to enhance adhesion.

Purpose of the Study:

• To measure and analyze the metal adhesion force to a parylene substrate for neural probe applications.
• To evaluate the effectiveness of CF4 plasma treatment on improving metal adhesion.
• To understand delamination behavior using Finite Element Method (FEM) modeling.

Main Methods:

• Fabrication of a test device with gold and titanium electrodes on a parylene substrate.
• Application of CF4 plasma treatment to the parylene substrate prior to metal deposition.
• Measurement of metal adhesion force using a scotch tape test with varying tape angles.
• FEM simulation of the scotch tape test to analyze delamination.

Main Results:

• Metal adhesion force was estimated to be 1.3 J/m2.
• A distinct peak in the force-displacement curve indicated metal delamination.
• CF4 plasma treatment was applied to mitigate delamination during fabrication.
• FEM modeling provided insights into the delamination mechanisms.

Conclusions:

• The study successfully quantified metal adhesion force on parylene substrates for neural probes.
• CF4 plasma treatment is a viable method for enhancing metal adhesion.
• FEM analysis aids in understanding and predicting delamination behavior in neural probe fabrication.