Storage Node Pillar Shaping for Semiconductor Memory
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Solution Overview
Problem
In semiconductor memory devices, increasing the height of capacitor columns in high aspect ratio pillars makes it difficult to expand the pitch between capacitors without causing the structure to taper, leading to issues like dielectric shorts and pinch-off due to insufficient width between capacitors.
Innovation Solution
A method involving the deposition of storage node material on the sides or within openings of support pillars, followed by etching it away from the pillar into the opening, which increases the width between capacitors, using a pattern of materials including oxide and nitride layers to form a support structure that maintains a static configuration and prevents tapering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the height of capacitor columns is increased in high aspect ratio pillars, then the capacitance is improved, but the width between capacitors becomes insufficient causing dielectric shorts and pinch-off
Solution Approach 1:
The support pillar is segmented into multiple functional layers including oxide layers, nitride layers, and sacrificial material layers. This segmentation allows each layer to perform its specific function: providing mechanical support, preventing tapering, and enabling controlled etching to increase the width between capacitors while maintaining high capacitance
Solution Approach 2:
A sacrificial material layer is introduced as an intermediary element between the support pillar and the capacitor columns. This sacrificial material is selectively removed through etching, allowing the capacitor columns to be spaced further apart while maintaining the high aspect ratio structure, thus preventing dielectric shorts and pinch-off
2Reliability
If the pitch between capacitors is increased, then the width between capacitors is improved preventing dielectric shorts, but the structure begins to taper reducing manufacturing precision
Solution Approach 1:
The support pillar structure with oxide and nitride layers is formed in advance before the capacitor columns are fully defined. This preliminary structure maintains the vertical alignment and prevents tapering during subsequent processing steps, allowing the pitch between capacitors to be increased without compromising manufacturing precision
Solution Approach 2:
The etching process selectively removes the sacrificial material layer based on differences in material properties. By controlling the etching parameters and selectivity, the width between capacitors is increased while maintaining the precise vertical configuration of the support pillar, thus resolving the contradiction between reliability and manufacturing precision
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 effectively increases the width between capacitors, preventing dielectric shorts and pinch-off issues while maintaining the structural integrity of the memory device, allowing for higher capacitance and reliable data storage.
Implementation Method 1
depositing a storage node material on a side of the pillar and/or filling an opening created by etching through the pattern of materials
Implementation Method 2
etching the storage node material in a direction from the pillar into the storage node
Data Source
AI summary
Methods, apparatuses, and systems related to shaping a storage node material are described. An example method includes forming a pillar with a pattern of materials. The method further includes depositing a storage node material on a side of the pillar. The method further includes etching sacrificial materials within the pillar. The method further includes etching the storage node material in a direction from the pillar into the storage node.