A chip integration method for implantable devices based on structural embedding using cyclic olefin copolymer.

Area of Science:

• Biomedical Engineering
• Materials Science
• Microelectronics

Background:

• Chip integration in implantable devices faces challenges from fluid exposure, mechanical stress, and space limitations.
• Current packaging methods can lead to reliability issues and fluid ingress.
• Developing robust, space-efficient integration is critical for advanced medical implants.

Purpose of the Study:

• To present a new chip integration strategy using structural embedding with cyclic olefin copolymer (COC).
• To evaluate the reliability and performance of embedded chips under conditions relevant to implantation.
• To demonstrate a monolithic, space-efficient, and mechanically robust solution for implantable electronics.

Main Methods:

• Structural embedding of integrated circuit chips into a COC substrate using an inverse truncated pyramid (ITP) geometry.
• Comprehensive testing including biocompatibility, electrical connectivity (with PEDOT:PSS reinforcement), mechanical/thermal reliability, long-term insulation, and functional validation.
• Finite element analysis (FEA) to assess stress distribution and heat dissipation.

Main Results:

• Achieved 87% electrical connectivity yield after PEDOT:PSS reinforcement.
• ITP geometry effectively redistributed mechanical stress and dissipated heat.
• Demonstrated stable electrical insulation for 380 days, projecting a 14.5-year operational lifetime.
• Embedded functional devices maintained stable electrical performance.

Conclusions:

• The structural embedding strategy enables monolithic, space-efficient, and mechanically robust chip integration.
• The approach addresses key challenges for implantable device reliability.
• This method offers a promising foundation for developing compact and dependable implantable devices with integrated electronics.