Bonding methods for chip integration with Parylene devices

Area of Science:

• Materials Science
• Electrical Engineering
• Nanotechnology

Background:

• Flexible electronics demand miniaturized interconnects for advanced device integration.
• Bonding flexible polymer devices to rigid integrated circuit chips presents significant technical hurdles.
• Current bonding technologies often lack the required density or involve complex, specialized processes.

Purpose of the Study:

• To adapt and evaluate existing bonding techniques for fine-pitch interconnects between rigid and flexible substrates.
• To introduce and investigate a novel bonding method: polymer ultrasonic on bump (PUB) bonding.
• To assess the performance and reliability of different bonding methods using Parylene C devices.

Main Methods:

• Adaptation of epoxy, ultrasonic wire, and anisotropic conductive film bonding techniques.
• Development and application of a novel polymer ultrasonic on bump (PUB) bonding method.
• Systematic investigation of four bonding methods on various rigid substrates with different bond pad sizes and pitches, using Parylene C devices.

Main Results:

• All investigated methods successfully achieved fine-pitch interconnects (100 μm) at low temperatures (<100 °C).
• Performance was evaluated through yield, resistance measurements, and thermomechanical reliability testing.
• The novel PUB bonding technique was demonstrated for joining packaged chips and bare dies to Parylene devices.

Conclusions:

• Multiple bonding strategies can achieve fine-pitch interconnects for flexible electronics at low temperatures.
• Polymer ultrasonic on bump (PUB) bonding offers a promising new approach for integrating flexible and rigid components.
• The study provides valuable insights into selecting and optimizing bonding methods for next-generation flexible electronic devices.