Semiconductor Memory Cell Layout With Shared Word Lines

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Solution Overview

Problem

The integration density of switch transistors in semiconductor structures is relatively low, limiting the number of memory cells that can be integrated in a given unit size, which affects the memory capacity.

Innovation Solution

A semiconductor structure design where only one word line is arranged between two adjacent active bodies, allowing simultaneous turn-on signals to be input to adjacent word lines to form a conductive channel, thereby reducing the space between active bodies and improving integration density, along with a manufacturing method that includes forming bit lines, active bodies, and word lines within an insulator, and doping semiconductor material to form source and drain regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If multiple word lines are arranged between adjacent active bodies, then each word line can independently control memory cells, but the space between active bodies increases, reducing integration density

Engineering Contradiction:
Improveintegration density of memory cellsVSAvoidnumber of word lines between active bodies
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent merges the control function of multiple word lines into a single shared word line. Adjacent active bodies share the same word line, and simultaneous turn-on signals are applied to adjacent word lines to form conductive channels between bit lines and capacitors. This combining approach reduces the number of word lines needed while maintaining independent control capability through signal timing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Each word line serves multiple functions: it acts as a control line for selecting memory cells and simultaneously forms part of the conductive channel when turned on. The word line structure is designed to be shared by adjacent active bodies, making it a universal element that performs both selection and conduction functions.

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

2Quantity of substance

If more memory cells are integrated in unit size, then memory capacity increases, but the space available for each memory cell decreases, making fabrication more difficult

Engineering Contradiction:
Improvenumber of memory cells in unit sizeVSAvoidfabrication difficulty
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent transitions from a planar two-dimensional layout to a three-dimensional structure by forming active bodies that extend vertically from the substrate. The bit lines are positioned at different heights (some on substrate, some in insulator), and word lines are formed in trenches within the insulator. This vertical stacking and multi-level arrangement increases integration density without proportionally reducing the fabrication area, thereby maintaining manufacturing precision while increasing memory cell count.

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

Solution Approach 2:

The patent implements a nested structure where active bodies are formed within the insulator material, word lines are embedded in trenches within the insulator, and bit lines are positioned both on the substrate and within the insulator. This nesting approach allows multiple components to occupy overlapping or adjacent spatial regions, effectively increasing the number of memory cells that can be packed into a given area while maintaining manufacturability.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 design enhances the integration density of memory cells on the semiconductor structure, allowing for a higher number of memory cells to be packed in a smaller area, thereby improving memory capacity.

Implementation Method 1

doping semiconductor material to form source and drain regions

Methodology Applied
Scientific EffectDoping: Dopants

Data Source

PatentEP3985672B1Semiconductor structure, and fabrication method and control method therefor
Publication Date: 2024.01.24 CHANGXIN MEMORY TECH INC
  • EP3985672B1 patent drawingFigure 1~2
  • EP3985672B1 patent drawingFigure 3~4
  • EP3985672B1 patent drawingFigure 5~6

AI summary

The present application relates to the technical field of storage and provides a semiconductor structure, and a manufacturing method and control method thereof. The semiconductor structure includes a base substrate, multiple bit lines, multiple active bodies, an insulator, and multiple word lines. The insulator is located on one side of the base substrate; the multiple bit lines are arranged in the insulator, and the multiple bit lines are distributed at intervals along a first direction and extend along a second direction; the multiple active bodies are located on sides of respective bit lines facing away from the base substrate, orthographic projection of each active body on the base substrate at least partially coincides with the orthographic projection of a respective bit line on the base substrate, and the active bodies are distributed at intervals along the second direction; the multiple word lines are located in the insulator and located on sides of respective bit lines facing away from the base substrate, the word lines are distributed at intervals along the second direction and extend along the first direction, and only one word line is arranged between two adjacent active bodies in the second direction. According to the semiconductor structure, more memory cells may be integrated in a limited space.