On-Chip Heat Spreader for 3D Stacked Chip Thermal Management
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Solution Overview
Problem
3D stacked chip structures generate significant heat during operation, posing a challenge for heat dissipation and potentially affecting the reliability and performance of the system due to high power consumption and resulting high operating temperatures.
Innovation Solution
Incorporating an on-chip heat spreader with elongate metal features extending from the center to the edges of the chip, which are insulated from bonding pads and interconnect metal features, to efficiently conduct heat away from local hotspots to the edges of the chip for dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If 3D stacked chip structure is used to improve system performance and reduce communication path length, then system speed and power efficiency are improved, but heat generation increases significantly
Solution Approach 1:
The patent introduces heat spreaders that extend in the planar dimension (horizontal direction) from the center to the edges of the chip, providing an additional thermal conduction path perpendicular to the vertical stacking direction. This dimensional approach allows heat to dissipate laterally across the chip surface rather than only vertically, effectively managing heat in high-density 3D stacked structures.
Solution Approach 2:
The heat spreader acts as an intermediary thermal conduction element between the heat-generating active regions (bonding pads and interconnect metal features) and the chip edges. These heat spreaders are electrically insulated from bonding pads but thermally conductive, serving as dedicated thermal pathways that mediate heat transfer without electrical interference.
2Temperature
If heat spreader is added to improve heat dissipation, then temperature control is improved, but device complexity increases
Solution Approach 1:
The heat spreader structure is merged with the existing inter-metal dielectric layers and bonding pad structures. The heat spreaders are formed within the same dielectric layers (IMD1, IMD2) that already exist for electrical interconnection, combining thermal management functionality with the existing electrical interconnect architecture rather than adding completely separate structures.
Solution Approach 2:
The dielectric layers serving as electrical insulation media also serve as the embedding medium for thermal conduction pathways. The same inter-metal dielectric layers that provide electrical isolation between metal interconnects also house the heat spreader structures, making them multi-functional elements that simultaneously handle both electrical and thermal management.
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
The on-chip heat spreader effectively diffuses heat across a larger surface area, improving heat dissipation and maintaining system reliability and performance even under high power consumption conditions.
Implementation Method 1
an on-chip heat spreader with elongate metal features extending from the center to the edges of the chip, which are insulated from bonding pads and interconnect metal features, to efficiently conduct heat away from local hotspots to the edges of the chip for dissipation
Data Source
AI summary
A three dimensional (3D) stacked chip structure with chips having on-chip heat spreader and method of forming are described. A 3D stacked chip structure comprises a first die having a first substrate with a dielectric layer formed on a front surface. One or more bonding pads and a heat spreader may be simultaneously formed in the dielectric layer. The first die is bonded with corresponding bond pads on a surface of a second die to form a stacked chip structure. Heat generated in the stacked chip structure may be diffused to the edges of the stacked chip structure through the heat spreader.