Reduced Inductance Interconnect for Millimeter-Wave Systems
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Solution Overview
Problem
Conventional microwave and millimeter-wave systems face limitations in high-frequency operations due to long interconnect lengths, which result in high inductance and thermal inefficiencies, leading to reduced performance and increased complexity in radar systems.
Innovation Solution
A reduced inductance interconnect system is achieved by embedding an integrated circuit in a pocket within a dielectric layer attached to a metal substrate, with a minimized interconnect length and enhanced heat dissipation through the metal layer, allowing for a higher density of channels and increased operating frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional interconnect structures are used to couple radiator fins to integrated circuits, then the system can be manufactured with standard processes, but the interconnect length becomes too long resulting in high inductance that limits high-frequency operation
Solution Approach 1:
The patent transitions from a planar interconnect layout to a three-dimensional structure by forming a recess in the substrate and placing the integrated circuit within it. This vertical arrangement dramatically shortens the interconnect length between the radiator fin and the integrated circuit, reducing inductance and enabling high-frequency operation above 95 GHz.
Solution Approach 2:
The integrated circuit is nested within a recess formed in the substrate, with the interconnect structure wrapping around and connecting to the circuit from multiple directions. This nested configuration minimizes the distance and number of interconnect paths, reducing overall inductance while maintaining a compact form factor.
2Device complexity
If flip chip techniques are used to reduce interconnect length, then inductance is reduced, but the fabrication process becomes complex and thermal dissipation problems arise
Solution Approach 1:
The patent extracts the integrated circuit from the conventional planar surface and places it within a recess in the substrate. This extraction allows the interconnect to be formed directly in the substrate material surrounding the recess, eliminating the need for complex bump formation and reflow processes required in flip chip techniques, while still achieving short interconnect lengths.
3Device complexity
If flip chip design is used to shorten bond connections, then inductance is reduced, but heat dissipation becomes inefficient requiring complex cooling systems
Solution Approach 1:
The substrate recess serves multiple functions: it positions the integrated circuit to minimize interconnect length, provides mechanical support, and creates a thermal management pathway. The interconnect structure surrounding the recess acts as both an electrical connection and a thermal conduction path, efficiently conducting heat away from the integrated circuit without requiring separate complex cooling systems.
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 configuration reduces inductance, improves circuit performance, enables higher frequency operations, and increases the number of radiator fins per square inch, allowing radar systems to operate at frequencies exceeding 95 gigahertz with improved thermal management.
Implementation Method 1
the integrated circuit is supported directly on a metal layer such that heat generated by the integrated circuit may be removed from the semiconductor system through the metal layer
Data Source
AI summary
According to one embodiment of the present invention, a microwave or millimeter wave module includes a dielectric layer having a pocket formed substantially through the dielectric layer. The dielectric is attached to a metal substrate. The pocket has substantially vertical sidewalls. An integrated circuit is disposed in the pocket. Opposing sides of the integrated circuit are substantially parallel to the sidewalls of the pocket. An interconnect electrically couples the integrated circuit to a bond pad disposed on the outer surface of the dielectric layer. The interconnect has a length that is minimized to result in reduced inductance of the semiconductor device.