3D Stacked Memory Thermal Management via Dynamic Refresh Control

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Solution Overview

Problem

3D stacked memory devices face thermal imbalances due to their complex thermal signature, leading to inefficient cooling and mechanical stress, where conventional cooling methods often over-engineer the design, resulting in inefficiency and bandwidth waste.

Innovation Solution

Implementing thermal sensors to monitor temperature gradients within the memory stack, dynamically adjusting refresh rates and data mapping to address thermal imbalances, and utilizing frequency and voltage throttling to maintain efficient operation while reducing heat stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cooling is dimensioned for worst-case scenario to reduce hot spots, then thermal reliability is improved, but device complexity and manufacturing efficiency deteriorate

Engineering Contradiction:
Improvethermal reliabilityVSAvoidcooling system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic refresh rate adjustment based on real-time temperature monitoring. The memory controller dynamically modifies refresh rates for different memory portions based on their current thermal state, transitioning from static worst-case cooling design to adaptive thermal management. This resolves the contradiction by maintaining reliability through active monitoring while reducing the need for over-engineered passive cooling infrastructure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters (refresh rates, voltage levels, clock frequencies) based on measured temperature conditions. By adjusting these parameters dynamically, the system adapts to actual thermal conditions rather than designing for maximum possible heat generation, thereby reducing manufacturing complexity while maintaining reliability.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If uniform cooling is applied to entire memory stack, then manufacturing simplicity is improved, but thermal efficiency deteriorates due to over-cooling outer portions

Engineering Contradiction:
Improvecooling design simplicityVSAvoidcooling energy efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent applies different refresh rates and thermal management policies to different portions of the memory stack based on their specific thermal characteristics. Inner portions receive different treatment than outer portions, with operations dynamically adjusted according to local temperature conditions. This resolves the contradiction by maintaining manufacturing simplicity while improving thermal efficiency through localized adaptive control.

Inventive Principle:
Principle #3Local quality

3Reliability

If high refresh rates are maintained for all memory portions, then data reliability is improved, but bandwidth efficiency deteriorates

Engineering Contradiction:
Improvedata retention reliabilityVSAvoidmemory bandwidth efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system dynamically adjusts refresh rates based on actual thermal conditions rather than maintaining uniformly high refresh rates. When portions of the memory stack are within acceptable temperature ranges, refresh rates are reduced, freeing up bandwidth for data operations. This resolves the contradiction by maintaining data reliability only where thermally necessary while optimizing overall bandwidth efficiency.

Inventive Principle:
Principle #15Dynamics

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 ensures a more balanced thermal setup, reduces mechanical stress, and optimizes bandwidth usage by dynamically adapting to thermal conditions, enhancing the operational efficiency and robustness of 3D stacked memory devices.

Implementation Method 1

thermal sensors to monitor temperature gradients within the memory stack

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2761620B1Dynamic operations for 3D stacked memory using thermal data
Publication Date: 2020.04.29 INTEL CORP
  • EP2761620B1 patent drawingFigure 1
  • EP2761620B1 patent drawingFigure 2
  • EP2761620B1 patent drawingFigure 3

AI summary

Dynamic operations for operations for 3D stacked memory using thermal data. An embodiment of a memory device includes memory having multiple coupled memory elements and multiple thermal sensors, including a first thermal sensor in a first area of the memory stack and a second thermal sensor in a second area of the memory stack. A memory controller is to provide operations to modify thermal conditions of the memory elements based at least in part on thermal information generated by the thermal sensors.