Low-Capacitance Interconnect Structure With Thermal Pillars and Air Gaps
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Solution Overview
Problem
The challenge in semiconductor manufacturing is to achieve high thermal conductivity in back-end-of-line (BEOL) interconnect structures while maintaining low parasitic capacitance, as low-k dielectric materials used for capacitance reduction have low thermal conductivities, hindering effective heat dissipation from front-end-of-line (FEOL) devices.
Innovation Solution
The method involves forming contact structures with high thermal conductivity pillar features, such as diamond or aluminum nitride, and creating air gaps using a sacrificial polymer layer to reduce capacitance, allowing for efficient heat dissipation and low parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If low-k dielectric materials are used in BEOL interconnect structures, then parasitic capacitance is reduced, but thermal conductivity deteriorates
Solution Approach 1:
The interconnect structure is segmented into multiple functional layers: low-k dielectric layers for capacitance reduction, high-k dielectric layers for thermal management, and metal interconnect layers. This segmentation allows each layer to optimize its specific function without compromising the other.
Solution Approach 2:
The patent employs composite dielectric structures combining low-k and high-k dielectric materials in a stratified arrangement. The low-k layers provide electrical isolation while the high-k layers provide thermal conduction pathways, creating a composite material system that simultaneously achieves low capacitance and high thermal conductivity.
2Productivity
If device dimensions are scaled down, then production efficiency is improved and costs are reduced, but manufacturing process complexity increases
Solution Approach 1:
The manufacturing process is divided into distinct stages: forming low-k dielectric layers, forming high-k dielectric layers, and creating metal interconnect structures. This segmentation of the manufacturing process allows each stage to be optimized independently, managing complexity while maintaining scalability.
Solution Approach 2:
The dielectric layers serve multiple functions: electrical isolation, thermal management, and mechanical support. This multi-functionality reduces the need for additional specialized components and process steps, thereby managing manufacturing complexity while maintaining device performance.
3Speed
If low-k dielectric materials are used, then capacitance is reduced, but thermal conductivity is insufficient for effective heat dissipation
Solution Approach 1:
High-k dielectric layers are introduced as intermediary thermal conduction pathways between the metal interconnect structures and the substrate. These intermediary layers provide dedicated thermal management functionality without interfering with the electrical isolation provided by the low-k dielectric layers.
Solution Approach 2:
The patent creates a composite dielectric system where low-k and high-k materials are strategically positioned to achieve both low capacitance and high thermal conductivity. The high-k layers form thermal conduction pathways that complement the electrical isolation function of the low-k layers.
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 approach effectively enhances heat dissipation through high thermal conductivity pillar features while maintaining low capacitance by creating air gaps, addressing the thermal conductivity limitations of low-k dielectric materials in BEOL interconnect structures.
Implementation Method 1
high thermal conductivity pillar features, such as diamond or aluminum nitride... efficiently dissipate heat from front-end-of-line (FEOL) devices
Implementation Method 2
creating air gaps using a sacrificial polymer layer to reduce capacitance
Data Source
AI summary
Contact structures and methods of forming the same are provided. A contact structure according to the present disclosure includes an etch stop layer (ESL), a first pillar feature and a second pillar feature disposed on the ESL, a metal feature disposed between the first pillar feature and the second pillar feature, the metal feature including a first sidewall, a bottom surface, a second sidewall, and a top surface, a dielectric liner extending continuously from a top surface of the first pillar feature, along the first sidewall, the bottom surface and the second sidewall of the metal feature, and onto a top surface of the second pillar feature, and a gap between the first pillar feature and a portion of the dielectric liner that extends along the first sidewall of the metal feature.