Backside IC Thermal Vias and Heat Spreader Layers for Hot Spot Relief
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Solution Overview
Problem
As technology nodes become smaller, the removal of the device substrate for backside features in integrated circuits (ICs) leads to poorer thermal dissipation, causing higher temperatures and device degradation due to the lack of effective heat management solutions.
Innovation Solution
Incorporating thermal vias and heat spreader layers in the IC structure to dissipate heat and reduce hot spots, utilizing materials like diamond and copper for thermal conductivity and electrical insulation, formed during back-end-of-line processes to avoid high-temperature stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the device substrate is removed or thinned down to form backside IC features, then chip space is optimized and power connections are improved, but thermal dissipation capability deteriorates causing hot spots and device degradation
Solution Approach 1:
The patent divides the thermal management function into multiple components: thermal vias (vertical heat conduction paths) and heat spreader layers (lateral heat distribution). This segmentation allows the thin substrate to maintain adequate thermal dissipation by distributing heat through multiple pathways rather than relying solely on the bulk substrate.
Solution Approach 2:
The patent introduces thermal vias filled with high thermal conductivity material (such as diamond or copper) as intermediary structures between the heat-generating devices and the heat spreader layers. These thermal vias act as thermal conduits that bridge the thermal gap created by substrate thinning, enabling effective heat transfer without requiring a thick substrate.
2Temperature
If thermal vias and heat spreader layers are added to improve thermal dissipation, then temperature control is improved, but device complexity increases
Solution Approach 1:
The thermal vias serve multiple functions: they provide thermal conduction pathways, act as structural support in the thinned substrate, and can be integrated with existing via structures in the interconnect layers. The heat spreader layers similarly serve both thermal management and as mechanical support structures, reducing the need for additional dedicated components.
Solution Approach 2:
The patent merges thermal management functions with existing structural elements. Thermal vias are combined with interconnect vias where possible, and heat spreader layers are integrated into the substrate structure itself. This merging approach allows thermal management to be achieved without adding completely separate, independent components that would increase complexity.
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
Effectively reduces temperature and hot spots in IC structures with backside power delivery networks, improving power delivery performance and allowing for further standard cell height scaling without affecting existing structures.
Implementation Method 1
Incorporating thermal vias and heat spreader layers in the IC structure to dissipate heat
Implementation Method 2
utilizing materials like diamond and copper for thermal conductivity
Data Source
AI summary
An IC structure includes a frontside interconnect structure on a front side of a device layer, the frontside interconnect structure includes first metal features and second metal features isolated from each other by and embedded in an IMD layer, the first metal features are electrically connected to the transistor devices, and the second metal features are electrically isolated from the transistor devices; a backside interconnect structure on a back side of the device layer, the backside interconnect structure includes third metal features and fourth metal features isolated from each other by and embedded in a backside IMD layer, the third metal features are electrically connected to the transistor devices, and the fourth metal features are electrically isolated from the transistor devices. The IC structure further includes a heat spreader layer having a material that is thermally conductive and electrically insulating on a back side of the backside interconnect structure.