3D Flash Memory via Through-Silicon Vias

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Solution Overview

Problem

Current flash memory technologies lack three-dimensional structures, which limits efficiency in physical space utilization, manufacturing complexity, power usage, thermal characteristics, and cost effectiveness.

Innovation Solution

The implementation of three-dimensional flash memory systems using through-silicon vias (TSVs) to connect multiple dies within a single package, allowing for efficient sharing of circuit blocks and reducing the need for redundant components, while utilizing TSVs strategically to avoid interference with flash arrays and enabling testing of good dies before stacking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If three-dimensional stacked die structure is implemented, then physical space utilization is improved, but device complexity increases

Engineering Contradiction:
Improvephysical space utilizationVSAvoiddevice complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent transitions from a two-dimensional planar arrangement of flash memory dies to a three-dimensional stacked configuration using through-silicon vias (TSVs) for vertical interconnection. This dimensional change enables significantly improved physical space utilization by stacking multiple dies vertically, allowing the memory system to achieve higher capacity density without proportionally increasing the footprint area.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent divides the flash memory system into multiple separate dies that are stacked vertically, with each die containing specific functional blocks. This segmentation allows different dies to be independently fabricated, tested, and then combined through TSV interconnections, managing the overall device complexity by breaking down the monolithic structure into modular units.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If circuit blocks are shared across multiple dies, then manufacturing complexity is reduced, but device complexity increases

Engineering Contradiction:
Improvemanufacturing complexityVSAvoiddevice complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent implements shared circuit blocks such as charge pumps and control logic that serve multiple flash memory arrays across different dies. For example, a single charge pump circuit can provide voltage boosting for program and erase operations to multiple dies, and control logic can manage sectors distributed across the stacked structure. This multi-functionality reduces manufacturing complexity by eliminating redundant components while the TSV interconnection system manages the increased device complexity through organized vertical routing.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Volume of moving object

If through-silicon vias are used for interconnection, then physical space efficiency is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvephysical space efficiencyVSAvoidmanufacturing precision
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The patent employs through-silicon vias (TSVs) to create vertical interconnections between stacked dies, transitioning the interconnection architecture from lateral routing to vertical routing. This enables compact three-dimensional integration where multiple dies are connected through the thickness of the stack, significantly improving physical space efficiency by reducing the footprint area required for equivalent memory capacity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent utilizes copper filling of TSVs with electroplating processes, which involves controlled deposition of conductive material through the via holes. This manufacturing technique requires precise control of plating parameters to ensure complete via fill and proper via-to-pad alignment, thereby increasing manufacturing precision requirements while achieving the benefits of three-dimensional integration.

Inventive Principle:
Principle #29Pneumatics and hydraulics

4Use of energy by moving object

If multiple dies are stacked in a single package, then power consumption is reduced, but thermal management challenges increase

Engineering Contradiction:
Improvepower consumptionVSAvoidthermal characteristics
Core Design Contradiction:
Use of energy by moving objectVSTemperature

Solution Approach 1:

The patent combines multiple flash memory dies into a single integrated package with shared power and ground networks. By stacking dies and using TSVs for interconnection, the system achieves more efficient power distribution and reduces overall power consumption compared to separate packages. The shared control logic and peripheral circuits further contribute to reduced power usage, though this consolidation creates thermal management challenges due to the concentrated heat generation in the stacked structure.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3267441B1Three-dimensional flash memory system
Publication Date: 2021.09.01 SILICON STORAGE TECHNOLOGY INC
  • EP3267441B1 patent drawingFigure 1
  • EP3267441B1 patent drawingFigure 2
  • EP3267441B1 patent drawingFigure 3

AI summary

A three-dimensional flash memory system is disclosed.