IC Interconnect Heat Dissipation Using Diamond Composite Dielectrics
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Solution Overview
Problem
The challenge in semiconductor integrated circuits (ICs) is to integrate heat dissipation structures while adhering to the thermal budget constraints of back-end-of-line (BEOL) processes, as conventional methods often exceed these limits, impacting performance and longevity.
Innovation Solution
A method involving the deposition of a seed layer followed by the growth of a diamond layer on the signal transmission structure, forming a composite dielectric layer that allows for heat dissipation within the thermal budget of BEOL processes, using materials like cubic boron nitride for the seed layer and diamond for high thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional heat dissipation structures are integrated into ICs, then thermal conductivity is improved, but thermal budget constraints of BEOL processes are exceeded
Solution Approach 1:
The patent employs a composite dielectric layer comprising a cubic boron nitride (c-BN) seed layer and a diamond layer. This composite structure combines materials with complementary properties: c-BN provides a stable foundation with good thermal conductivity, while the diamond layer delivers exceptional thermal conductivity (20-50 times that of copper) to effectively dissipate heat from the IC without exceeding BEOL thermal budget constraints.
Solution Approach 2:
The patent utilizes chemical vapor deposition (CVD) to grow the diamond layer on the c-BN seed layer under controlled parameters (temperature, pressure, gas composition). By optimizing these deposition parameters, the method achieves high-quality diamond growth with superior thermal conductivity while maintaining process temperatures compatible with BEOL manufacturing constraints.
2Temperature
If diamond layer is grown on signal transmission structure, then thermal conductivity is enhanced, but surface roughness increases
Solution Approach 1:
The cubic boron nitride (c-BN) seed layer serves as an intermediary between the signal transmission structure and the diamond layer. This intermediate layer provides a chemically stable and structurally uniform foundation that promotes homogeneous diamond nucleation and growth, resulting in a smoother final surface while maintaining the high thermal conductivity benefits of the diamond layer.
Solution Approach 2:
The patent applies different materials with specific local properties: the c-BN seed layer is optimized for chemical stability and nucleation properties, while the diamond layer is optimized for thermal conductivity. This local differentiation of material properties allows each layer to perform its specific function optimally, achieving both smooth surface and high thermal performance.
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 enables effective heat dissipation and improved performance and longevity of ICs by maintaining compatibility with existing manufacturing processes, enhancing thermal conductivity and reducing surface roughness.
Implementation Method 1
a seed layer is deposited on the signal transmission structure
Implementation Method 2
a seed layer is deposited on the signal transmission structure
Implementation Method 3
a diamond layer is grown on the seed layer
Data Source
AI summary
An integrated circuit includes a semiconductor substrate and an interconnect structure. The interconnect structure is disposed on the semiconductor substrate. The interconnect structure includes a signal transmission structure and a heat dissipation structure. The heat dissipation structure is disposed on the signal transmission structure and includes composite dielectric layers and first conductive features. Each of the composite dielectric layers includes a seed layer and a heat dissipation layer disposed on the seed layer. The first conductive features are embedded in the composite dielectric layers.