Semiconductor Pillar Interconnect for High Current and Thermal Dissipation
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Solution Overview
Problem
Existing semiconductor structures face challenges with parasitic inductance and inefficient heat dissipation due to wire-bonding, and the use of multiple metal layers results in reduced photolithographic resolution and increased die size, limiting current-handling capability.
Innovation Solution
A semiconductor structure with a minimal number of metal layers, featuring a conductive pillar directly on and in electrical contact with a metal layer, and a dielectric layer for electrical isolation, which allows for efficient thermal and electrical connections while eliminating the need for a continuous upper metal layer, thereby enhancing current-carrying capability and reducing feature size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple metal layers are used for signal routing, then signal routing capability is improved, but photolithographic resolution is reduced and die size increases
Solution Approach 1:
The patent transitions from a planar multi-layer metal interconnect structure to a three-dimensional structure where a thick upper metal layer is positioned directly over the semiconductor device, with signal routing achieved through vertical vias and lateral traces in the same or fewer metal layers. This dimensional change allows thicker metal features to be formed with better photolithographic resolution while maintaining signal routing capability through the reconfigured interconnect architecture.
2Productivity
If a thick upper metal layer is used, then current-handling capability is improved, but the layer cannot be used for signal routing under the pillar
Solution Approach 1:
The patent segments the interconnect function by dedicating the thick upper metal layer primarily to current carrying and ground functions, while signal routing is handled by separate trace structures in the same or lower metal layers. This segmentation allows each metal layer to be optimized for its specific function, with the thick upper layer providing high current capacity and separate thinner layers providing precise signal routing paths.
Solution Approach 2:
The patent creates multi-functional interconnect structures where metal layers serve multiple purposes: the upper metal layer provides both ground reference and current return paths, while also containing signal traces that route information. This multi-functionality is achieved through careful layout design where ground fills, current paths, and signal traces coexist in the same metal layer system, allowing the thick metal to fulfill both high-current carrying and signal routing roles simultaneously.
3Device complexity
If wire-bonding is used for electrical connections, then connection simplicity is improved, but parasitic inductance increases and heat dissipation efficiency is reduced
Solution Approach 1:
The patent extracts and eliminates the wire-bonding interconnect element entirely, replacing it with direct metal-to-semiconductor and metal-to-metal connections formed through photolithographic patterning and deposition. This removal of the wire-bond eliminates the associated parasitic inductance and thermal resistance, while the resulting planar metal interconnect structure provides simpler fabrication integration despite increased electrical performance requirements.
4Device complexity
If wire-bonding is used for heat dissipation, then thermal connection simplicity is improved, but heat dissipation efficiency is reduced
Solution Approach 1:
The patent merges the electrical interconnect and thermal management functions into a unified planar metal interconnect structure. The same metal layers that provide electrical connections also serve as heat sinks and thermal conduction paths, with thick metal regions providing both electrical ground/current functions and thermal dissipation. This merging eliminates the need for separate wire-bond thermal paths and creates efficient thermal coupling between the semiconductor device and the package substrate through the metal interconnect system.
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 improves current-carrying capability, reduces feature size, and enhances heat dissipation by allowing a thicker upper metal layer for signal routing under the pillar, addressing the inefficiencies of wire-bonding and multiple metal layer structures.
Implementation Method 1
a dielectric layer selectively disposed between the metal layer and the conductive pillar. The dielectric layer electrically isolates the second electrical trace from the pillar
Implementation Method 2
the pillar 109 provides a thermal dissipation path and electrical ground through the third metal layer 108
Implementation Method 3
The first metal layer 106 and the second metal layer 107 are used for routing signals to and from the HBT
Data Source
AI summary
A semiconductor structure comprises a substrate and a metal layer disposed over the substrate. The metal layer comprises a first electrical trace and a second electrical trace. The semiconductor structure comprises a conductive pillar disposed directly on and in electrical contact with the first electrical trace; and a dielectric layer selectively disposed between the metal layer and the conductive pillar. The dielectric layer electrically isolates the second electrical trace from the pillar.