Embedded Low-Power Chip Thermal Isolation in IC Stacks
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Solution Overview
Problem
In integrated circuit (IC) chip packaging, there is a trade-off between thermal management and device performance, where high-power chips generate heat that adversely affects nearby low-power chips, making it thermally infeasible to stack memory chips and passive devices directly under or on high-power chips, and a horizontally distributed configuration results in an impractically large footprint with longer interconnect paths.
Innovation Solution
A stacked configuration where a low-power chip is embedded in a packaging substrate with a high-power chip on top, using the substrate as a thermally insulating layer to prevent overheating, and through-silicon vias (TSVs) for short electrical connections, along with a heat-distribution layer to enhance thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If low-power chips are positioned close to high-power chips to shorten interconnect paths, then device performance is improved and interconnect parasitics are reduced, but the low-power chips overheat due to heat from high-power chips
Solution Approach 1:
The patent transitions from horizontal placement to vertical stacking, moving components into the third dimension. Low-power chips are stacked above high-power chips on the same substrate, achieving close proximity for short interconnect paths while the substrate's thermal properties prevent heat transfer, thus resolving the contradiction between speed improvement and temperature control.
Solution Approach 2:
The substrate serves as an intermediary between high-power and low-power chips. It provides electrical connectivity for short interconnect paths while its thermal insulation properties block heat transfer from high-power to low-power chips, enabling both performance improvement and temperature protection simultaneously.
2Area of stationary object
If low-power chips are stacked directly on or under high-power chips to minimize footprint, then packaging parasitics are reduced, but the low-power chips are damaged or performance is affected by overheating
Solution Approach 1:
The patent uses vertical stacking in the third dimension to achieve high integration density without increasing footprint. Low-power chips are positioned above high-power chips rather than beside them, minimizing the package area while the substrate's thermal insulation prevents overheating, thus maintaining reliability.
Solution Approach 2:
The substrate acts as a thermal intermediary that allows physical stacking for minimal footprint while blocking harmful heat transfer. This enables direct stacking configuration for space efficiency while the substrate's thermal properties protect low-power chips from overheating, preserving their reliability.
3Temperature
If high-power chips are positioned beside low-power chips in a horizontally distributed configuration, then thermal management is improved, but the IC package footprint becomes impractically large and interconnect paths become longer
Solution Approach 1:
The patent resolves the contradiction by moving from horizontal distribution to vertical stacking. High-power and low-power chips are arranged in different vertical layers on the same substrate area, achieving both close proximity for short interconnects and thermal isolation through the substrate, thus minimizing footprint while maintaining thermal management.
Solution Approach 2:
The substrate serves as a thermal intermediary that enables horizontal co-location of high-power and low-power chips without direct thermal coupling. This allows the package to maintain a compact footprint with short interconnect paths while the substrate's thermal insulation properties ensure proper thermal management by preventing heat transfer between chips.
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 configuration allows low-power chips to be positioned close to high-power chips without overheating, reducing interconnect parasitics and improving device performance by shortening interconnect paths and minimizing the IC package footprint.
Implementation Method 1
Because portions of the packaging substrate thermally insulate the embedded low-power chip from the high-power chip, the low-power chip can be positioned proximate the high-power chip without being overheated
Data Source
AI summary
An IC system includes low-power chips, e.g., memory chips, located proximate one or more higher power chips, e.g., logic chips, without suffering the effects of overheating. The IC system may include a high-power chip disposed on a packaging substrate and a low-power chip embedded in the packaging substrate to form a stack. Because portions of the packaging substrate thermally insulate the low-power chip from the high-power chip, the low-power chip can be embedded in the IC system in close proximity to the high-power chip without being over heated by the high-power chip. Such close proximity between the low-power chip and the high-power chip advantageously shortens the path length of interconnects therebetween, which improves device performance and reduces interconnect parasitics in the IC system.