Integrated Circuit Repackaging for High-Temperature Reliability
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Solution Overview
Problem
Integrated circuits packaged in commercial plastic packages are not suitable for high-temperature environments, as they experience reliability issues due to Au-Al intermetallic compound formation and Kirkendall voids, leading to premature failures, and are often obsolete or unavailable in necessary high-temperature hermetic packages.
Innovation Solution
A method to repackaging integrated circuit dice into hermetic packages by extracting and reconditioning the dice, removing existing ball bonds, and applying a sequence of metallic layers (electroless nickel, palladium, and immersion gold) to create reliable high-temperature-tolerant packaged integrated circuits without requiring new bare dice, allowing reuse in different hermetic packages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If commercial plastic packages are used for integrated circuits, then cost is reduced and manufacturing simplicity is improved, but reliability at high temperatures deteriorates due to Au-Al intermetallic compound formation and Kirkendall voids
Solution Approach 1:
The patent extracts the semiconductor die from its original commercial plastic package and removes the problematic Au-Al bond interface by eliminating the aluminum bond pads. The die is then repackaged in a hermetic package with alternative bonding structures that avoid Au-Al intermetallic formation, thereby extracting the harmful bonding mechanism while preserving the die functionality.
Solution Approach 2:
The patent employs composite packaging structures combining hermetic sealing materials with alternative bond pad configurations. The hermetic package base and lid create a protected environment, while the modified bond pads (using materials other than aluminum) provide reliable electrical connections without forming harmful intermetallic compounds, achieving both reliability and manufacturability.
2Reliability
If military-grade hermetic packages are used for integrated circuits, then high-temperature reliability is improved, but cost increases and manufacturing complexity worsens
Solution Approach 1:
The patent segments the packaging process into distinct stages: extracting the die from the original package, preparing the hermetic package base, bonding the die with modified pad structures, and sealing with the hermetic lid. This segmentation allows each step to be optimized independently, reducing overall manufacturing complexity while achieving military-grade reliability through the hermetic seal and improved bond interfaces.
3Adaptability or versatility
If integrated circuits are repackaged from commercial to hermetic packages, then adaptability to high-temperature environments is improved, but device complexity and processing steps increase
Solution Approach 1:
The patent creates a universal repackaging methodology that can be applied to various commercial integrated circuits regardless of their original package type. The process of extracting the die, modifying the bond pads, and repackaging in a hermetic container provides a multi-functional solution that adapts different commercial parts to high-temperature military applications, reducing the need for part-specific customization while achieving environmental adaptability.
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
The solution provides reliable operation at extended ambient temperatures, reduces the formation of intermetallic bond weaknesses, and allows for the reuse of existing components in high-temperature environments, overcoming the limitations of conventional packaging methods.
Implementation Method 1
applying a sequence of metallic layers (electroless nickel, palladium, and immersion gold) to create reliable high-temperature-tolerant packaged integrated circuits
Data Source
AI summary
A method is provided. The method includes one or more of extracting a die from an original packaged integrated circuit, modifying the extracted die, reconditioning the modified extracted die, placing the reconditioned die into a cavity of a hermetic package base, bonding a plurality of bond wires between reconditioned die pads of the reconditioned die to leads of the hermetic package base or downbonds to create an assembled hermetic package base, and sealing a hermetic package lid to the assembled hermetic package base to create a new packaged integrated circuit. Modifying the extracted die includes removing the one or more ball bonds on the one or more die pads. Reconditioning the modified extracted die includes adding a sequence of metallic layers to bare die pads of the modified extracted die. The extracted die is a fully functional semiconductor die with one or more ball bonds on one or more die pads of the extracted die.