Defect Filling Method of Sensor Encapsulation Based on Micro-Nano Composite Structure with Parylene Coating

Area of Science:

• Materials Science
• Nanotechnology
• Surface Engineering

Background:

• Parylene coatings are crucial for electronic device waterproofing but suffer from defects like pinholes and cracks.
• These defects compromise the protective barrier, especially for devices with moving parts.

Purpose of the Study:

• To develop a defect-filling method using a micro-nano composite structure to enhance the waterproof capabilities of parylene coatings.
• To improve the long-term reliability and performance of electronic devices in harsh environments.

Main Methods:

• A composite structure comprising a nano layer of aluminum oxide (Al2O3) and a micro layer of parylene polymer was proposed.
• Atomic layer deposition (ALD) was used to deposit dense Al2O3 nanoparticles to fill and repair surface defects.
• The diffusion mechanism of water molecules through the polymer membrane was leveraged to hinder penetration.

Main Results:

• The Al2O3 nanoparticles effectively filled defects, delaying water molecule penetration.
• Encapsulated pressure sensors maintained accuracy (2 mmHg) in saline solution for a duration equivalent to 153.9 days at body temperature.
• The proposed encapsulation improved sensor accuracy by approximately 43%.

Conclusions:

• The micro-nano composite defect-filling method significantly enhances the waterproof performance of parylene coatings.
• This approach offers broad application prospects for protecting micro/nano-devices, particularly in demanding environments.
• The study demonstrates a viable strategy for improving the durability and reliability of electronic components through advanced encapsulation techniques.