Electroplated Platinum Interconnection for Hermetic Implantable Electronics
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Solution Overview
Problem
Existing methods for bonding a flexible circuit to an electronics package for implantation in living tissue face biocompatibility and mechanical stability issues, particularly in a corrosive saline environment like the eye, where conventional materials like tin-lead solder and indium corrode, and known deposition techniques fail to achieve a strong, hermetic bond.
Innovation Solution
The use of electroplated platinum or gold interconnection bonding between a substrate and a flexible circuit, which ensures a biocompatible and long-lasting attachment suitable for implantation in living tissue, utilizing electroplating techniques to form a strong and conductive bond that is resistant to corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional bonding materials like tin-lead solder and indium are used to attach flexible circuit to electronics package, then mechanical bonding strength is achieved, but biocompatibility deteriorates due to corrosion in saline environment
Solution Approach 1:
The patent changes the material parameters by replacing conventional soldering materials (tin-lead, indium) with electroplated noble metals (gold, platinum). This material substitution maintains bonding strength while eliminating corrosion in saline environments, thereby preserving biocompatibility for implantable devices
Solution Approach 2:
The patent employs composite material structures by combining the flexible circuit substrate with electroplated metal layers. The electroplated gold or platinum forms a biocompatible interface layer that provides both mechanical bonding strength and corrosion resistance in the saline environment
2Reliability
If known deposition techniques are used to bond substrate to flexible circuit, then electrical connection is established, but mechanical stability deteriorates due to failure to achieve strong hermetic bond
Solution Approach 1:
The patent merges electrical connection and mechanical bonding functions into a single electroplating process. The electroplated metal layer simultaneously provides electrical conductivity for signal transmission and mechanical strength for hermetic bonding between the substrate and flexible circuit
Solution Approach 2:
The patent changes the deposition parameters by using electroplating instead of conventional deposition techniques. This process produces a dense, adherent metal layer that provides both excellent electrical contact and strong mechanical bonding, achieving hermetic sealing
3Ease of operation
If discrete wires are used to create electrode array, then flexibility is maintained, but electrode density deteriorates due to inability to accommodate high number of electrodes
Solution Approach 1:
The patent uses a thin-film flexible circuit substrate with lithographically fabricated electrode patterns. This thin-film structure maintains flexibility for implantation while enabling high-density electrode arrays through photolithographic patterning, accommodating many more electrodes than discrete wire approaches
4Quantity of substance
If thin film flex circuit is used to increase electrode density, then electrode capacity is improved, but manufacturing complexity deteriorates due to need for precise lithographic fabrication and bonding
Solution Approach 1:
The patent performs preliminary actions by pre-fabricating the flexible circuit with lithographically defined electrode and bond pad patterns before final assembly. This pre-fabrication enables precise electrode positioning and simplifies the bonding process, as the bond pads are already in their correct locations for alignment with package contacts
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method provides a hermetic, biocompatible electronics package that maintains long-term mechanical and electrical stability, ensuring reliable electrical interconnection and preventing tissue damage, suitable for neural interfaces like retinal implants.
Implementation Method 1
electroplated platinum or gold interconnection bonding
Data Source
AI summary
Device is a hermetically sealed electronics package bonded to an electrode or flexible circuit that is suitable for implantation such as for a retinal or cortical electrode array. The hermetically sealed electronics package is bonded to the electrode or flexible circuit by electroplating a biocompatible material, such as platinum or gold, forming a plated connection, bonding the flexible circuit to the electronics package. The resulting electronic device is biocompatible and is suitable for long-term implantation. The device comprises a substrate containing a contact, a flexible assembly containing a pad, and electroplated bonding between said contact and said pad that bonds said substrate and said flexible assembly together.