Backside Dummy Metal Features for 3D Chip Heat Dissipation
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Solution Overview
Problem
3D stacked semiconductor devices generate excessive heat with hotspots, necessitating improved thermal management directly from the semiconductor chips.
Innovation Solution
Incorporation of dummy features extending from the backside of the substrate, comprising metal layers, which are electrically isolated from the device and interconnect layers, to dissipate heat without occupying frontside space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermal management is performed on the outside of the device package, then heat dissipation is achieved, but the thermal management effectiveness is insufficient for high-density 3D stacked devices
Solution Approach 1:
The patent transitions from external package-level thermal management to internal chip-level thermal management by forming thermal management features within the semiconductor substrate. This dimensional shift from external to internal enables direct heat dissipation at the heat generation source, improving thermal effectiveness without adding external complexity
Solution Approach 2:
The patent introduces an intermediary thermal management feature (conductive material filled in recesses) that acts as a heat transfer medium between the heat-generating device layer and the external environment. This intermediary structure facilitates efficient heat conduction from internal hotspots to external heat sinks
2Temperature
If dummy features are formed on the frontside of the substrate, then thermal management is improved, but device area is reduced
Solution Approach 1:
The patent inverts the conventional approach by forming thermal management features on the backside of the substrate rather than the frontside. This inversion allows the device layer on the frontside to maintain full area for functional devices while the backside accommodates thermal management features that do not interfere with device operation
Solution Approach 2:
The patent segments the substrate into frontside (device layer) and backside (thermal management features), allowing independent optimization of each side. The device layer occupies the frontside for maximum functional area while thermal management features occupy the backside for heat dissipation
3Temperature
If conductive material is deposited in recesses to form thermal management features, then heat dissipation is improved, but manufacturing process complexity increases
Solution Approach 1:
The patent merges the formation of thermal management features with existing manufacturing processes such as recess formation and conductive material deposition. By integrating thermal management feature formation into the standard fabrication sequence, the patent avoids adding significant manufacturing complexity while achieving improved heat dissipation
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 dissipates heat from semiconductor chips, maintaining device functionality and interconnect integrity while optimizing space utilization.
Implementation Method 1
the at least one dummy feature comprises one or more metal layers... Effectively dissipates heat from semiconductor chips
Data Source
AI summary
Embodiments of the disclosure include a semiconductor die comprising: a substrate having a frontside opposing a backside; a device layer disposed over the frontside of the substrate; interconnect layers formed over the device layer; and at least one dummy feature. The at least one dummy feature extending from the backside of the substrate through a portion of the substrate, wherein the at least one dummy feature comprises one or more metal layers. The at least one dummy feature being electrically isolated from the device layer and the interconnect layers by a portion of the substrate.