Laminate Spacer Structures for Microelectronic Devices
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Solution Overview
Problem
Conventional methods for reducing feature spacing in microelectronic devices, such as DRAM cells, lead to undesirable electrical coupling effects and reliability issues due to the formation of air gaps, which can cause electrical shorts and require complex processes to mitigate.
Innovation Solution
The use of laminate spacer structures with a low-k dielectric spacer structure and discrete gas pockets dispersed within a dielectric material, supported by additional dielectric spacer structures, to reduce capacitive coupling and enhance feature density while maintaining device reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If air gaps are formed adjacent to digit lines to reduce capacitive coupling, then electrical coupling effects are reduced, but conductive material is attacked and reliability is reduced
Solution Approach 1:
A dielectric spacer structure is introduced as an intermediary material between the digit line and the air gap. This dielectric layer protects the conductive material from direct exposure to the air gap formation process while still achieving the desired electrical isolation. The dielectric spacer acts as a mediator that prevents harmful etching attacks on the conductive material while maintaining the capacitive coupling reduction benefits of the air gap.
Solution Approach 2:
The structure combines multiple materials - conductive material for the digit line, dielectric material for the spacer, and air for the gap - to create a composite structure that achieves both electrical isolation and material protection. This composite approach allows each material to perform its optimal function: the conductive material carries signals, the dielectric provides protection and structural support, and the air provides low-k insulation.
2Productivity
If feature spacing is reduced to increase integration density, then device density is improved, but electrical coupling effects increase
Solution Approach 1:
Air gaps are utilized as porous/void structures within the device architecture. These air gaps, while occupying space, provide effective electrical isolation due to air's low dielectric constant. The porous nature of the air gap structure allows for compact design while maintaining electrical separation, enabling higher integration density without excessive capacitive coupling.
Solution Approach 2:
The dielectric constant parameter is changed by introducing air gaps (k≈1) and dielectric spacers with optimized k-values into the structure. This parameter change reduces the overall capacitive coupling between adjacent digit lines, allowing features to be placed closer together while maintaining acceptable electrical isolation. The effective dielectric constant of the medium between conductors is reduced, enabling higher density.
3Object-affected harmful factors
If conventional air gap processes are used to reduce coupling, then capacitive coupling is reduced, but process complexity increases
Solution Approach 1:
The dielectric spacer structure is formed preliminarily before the air gap formation process. This preliminary action of depositing the dielectric spacer layer protects the conductive material in advance from potential etching attacks during subsequent air gap creation steps. By preparing this protective layer beforehand, the process avoids the need for complex mitigation steps later, simplifying the overall manufacturing process.
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 reduces capacitive coupling and improves the reliability of microelectronic devices by providing a lower dielectric constant and structural support, allowing for increased feature density without the drawbacks of conventional air gaps.
Implementation Method 1
The low-k dielectric spacer structure includes a dielectric material and discrete gas pockets dispersed within the dielectric material. The discrete gas pockets facilitate a lower dielectric constant for the low-k dielectric spacer structure
Implementation Method 2
The discrete gas pockets facilitate a lower dielectric constant for the low-k dielectric spacer structure relative to a dielectric spacer structure including the dielectric material but not the discrete gas pockets
Data Source
AI summary
An apparatus comprises a conductive structure, another conductive structure, and a laminate spacer structure interposed between the conductive structure and the another conductive structure in a first direction. The laminate spacer structure comprises a dielectric spacer structure, another dielectric spacer structure, and an additional dielectric spacer structure interposed between the dielectric spacer structure and the another dielectric spacer structure. The additional dielectric spacer structure comprises at least one dielectric material, and gas pockets dispersed within the at least one dielectric material. Additional apparatuses, memory devices, electronic systems, and a method of forming an apparatus are also described.