Nanocrystalline Diamond TSVs for Thermal Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Thermal management in semiconductor integrated circuits and discrete power devices faces challenges due to large thermal boundary resistance between SiC substrates and GaN nucleation layers, leading to a trade-off between power performance and reliability.
Innovation Solution
The growth of nanocrystalline diamond (NCD) in tapered through-silicon vias (TSVs) within a silicon substrate, which provides a high thermal conductivity path and can extend to cover the substrate surface, effectively creating a diamond substrate with improved thermal and mechanical properties without the challenges of single-crystal diamond growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If GaN device layers are grown on SiC substrates, then thermal conductivity is improved, but thermal boundary resistance increases
Solution Approach 1:
The substrate is segmented into multiple regions: SiC substrate regions for mechanical support and Si substrate regions with NCD-coated TSVs for thermal management. This segmentation allows each material to perform its optimal function without the thermal boundary resistance problem of GaN-on-SiC interfaces.
Solution Approach 2:
Nanocrystalline diamond-coated through-silicon vias act as intermediary thermal conduction paths between the GaN heat source and the SiC substrate. The NCD coating provides excellent thermal conductivity while the TSV structure creates direct thermal pathways, bypassing the problematic thermal boundary resistance at GaN-SiC interfaces.
2Temperature
If single-crystal diamond substrates are used, then thermal conductivity is improved, but manufacturing complexity increases
Solution Approach 1:
Instead of requiring a complete single-crystal diamond substrate, the invention applies nanocrystalline diamond coating locally to specific through-silicon via regions. This localized approach provides the necessary thermal conductivity where heat is generated, while avoiding the manufacturing challenges of large-area single-crystal diamond substrates.
Solution Approach 2:
The invention uses a composite structure combining silicon substrate, nanocrystalline diamond coating, and metal fill materials. This composite approach leverages the advantages of each material: Si for mechanical properties and CMOS compatibility, NCD for thermal conductivity, and metal for electrical connectivity, while avoiding the need for difficult-to-manufacture single-crystal diamond substrates.
3Temperature
If NCD film thickness is increased, then thermal conductivity is improved, but device scaling becomes difficult
Solution Approach 1:
The thermal conduction path is extended into the vertical dimension through deep through-silicon vias rather than relying solely on increased horizontal NCD film thickness. This vertical thermal pathway provides efficient heat extraction without adding significant lateral dimensions, enabling continued device scaling.
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 enhances thermal management in semiconductor devices by increasing the volumetric growth ratio of diamond, allowing for efficient heat transfer and improved device performance while maintaining substrate integrity and scalability.
Implementation Method 1
Nanocrystalline diamond (NCD) has been of interest for a number of applications owing to its attractive properties such as high thermal conductivity
Implementation Method 2
Nanocrystalline diamond films having a thickness of less than 1 μm are typically grown with rms roughness in the 20-100 nm range
Data Source
AI summary
An array of through-silicon vias (TSVs) are formed in a silicone substrate. The vias can be tapered such that the diameter of the via at the surface of the substrate is larger than the diameter of the via at its bottom, with the diameter varying continuously along its depth. After the via is formed, it is seeded with a thin layer of nanocrystalline diamond (NCD) particles, and a NCD film is grown on the bottom and along the sidewalls of the via. The presence of the diamond-filled vias provides improved thermal management to semiconductor devices formed on the silicon substrate.