Stacked Bond Wire Interconnects for Compact High-Frequency RF Packaging
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Solution Overview
Problem
High-frequency RF transistor amplifiers face challenges in achieving high reliability, linearity, and high output power handling due to inherent performance limitations of traditional packaging methods, which result in increased parasitic components and device size, especially at higher frequencies.
Innovation Solution
The use of stacked bond wire configurations in packaged semiconductor devices, where bond wires are overlapped to reduce contact pad size and increase current-carrying capability, thereby improving device performance and reliability by minimizing parasitic components and overall size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional wire bonding methods are used to interconnect transmission lines in RF transistor amplifiers, then the device can be manufactured with conventional processes, but parasitic components increase and device size increases at high frequencies
Solution Approach 1:
The patent replaces traditional mechanical wire bonding with a direct integration approach where bond wires are incorporated into the transmission line structure itself. The bond wires serve dual functions as both mechanical interconnects and electrical transmission lines, eliminating the need for separate wire bonding processes and reducing parasitic components by integrating the interconnection function into the transmission line geometry.
Solution Approach 2:
The bond wires are designed to perform multiple functions simultaneously: they serve as mechanical interconnects between components and as electrical transmission lines for RF signals. This multi-functionality reduces the number of separate elements needed, thereby reducing parasitic components and improving device reliability at high frequencies.
2Ease of manufacture
If traditional wire bonding is used for interconnection, then manufacturing flexibility is maintained, but device size increases due to larger contact pad requirements
Solution Approach 1:
The patent transitions from planar contact pad arrangements to a three-dimensional stacked bond configuration. Multiple bond wires are stacked vertically to connect to the same contact pad, allowing current to be distributed across multiple wires while reducing the horizontal area required for contact pads. This vertical stacking approach maintains manufacturing flexibility while significantly reducing device footprint.
3Power
If conventional packaging methods are used, then standard fabrication processes can be employed, but current-carrying capability is limited due to larger device size
Solution Approach 1:
The patent merges multiple bond wires into a stacked configuration where they share common connection points. This combining of multiple current paths increases the overall current-carrying capability without proportionally increasing device volume, as the wires are stacked vertically rather than spread out horizontally. The merged structure allows higher power handling in a compact footprint.
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 stacked bond wire configuration enhances the performance of RF transistor amplifiers by reducing parasitic components and device size, allowing for wider operational bandwidth and improved reliability at high frequencies.
Implementation Method 1
Bond wires may comprise aluminum, copper, silver and/or gold. Wire bond attachment techniques may include ball bonding, wedge bonding and/or compliant bonding. In ball bonding and wedge bonding, the wire is attached at both ends using some combination of heat, pressure and ultrasonic energy to make a weld.
Data Source
AI summary
A packaged semiconductor device includes a first bond pad, a second bond pad, a first bond wire that includes a first end bonded to the first bond pad and a second end bonded to the second bond pad, and a second bond wire that includes a first end that is electrically connected to the first bond pad and a second end that is electrically connected to the second bond pad. The first end of the second bond wire is bonded to the first end of the first bond wire. A method of bonding a bond wire includes bonding a first end of a first bond wire to a contact surface of a first bond pad and bonding a first end of a second bond wire to a surface of the first end of the first bond wire.