Semiconductor Air Spacer Design for Parasitic Capacitance Reduction
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Solution Overview
Problem
As the integration of semiconductor devices increases, the distance between adjacent conductive patterns decreases, leading to increased cross-talk and parasitic capacitance, which impede the flow of electrical signals and reduce the bit line sensing margin, necessitating a reduction in parasitic capacitance between adjacent conductive patterns.
Innovation Solution
The implementation of a semiconductor device design that includes lower air spacers with line shapes and an upper air spacer of a ring shape, which surrounds the side surfaces of the contact structure, to reduce parasitic capacitance by maximizing the thickness of the lower air spacers and minimizing the bit line loading capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the distance between adjacent conductive patterns is reduced to increase integration, then device integration increases, but parasitic capacitance between conductive patterns increases
Solution Approach 1:
An air spacer structure is introduced as an intermediary element between adjacent conductive patterns (bit lines). The air spacer has a lower dielectric constant than conventional insulating materials, creating a mediator that reduces the parasitic capacitance coupling between the conductive patterns while allowing them to remain in close proximity for high integration.
Solution Approach 2:
The dielectric constant parameter of the insulating material between conductive patterns is changed from conventional high-k materials to air (k≈1). This parameter change is achieved by forming air gaps through selective removal of insulating material, thereby reducing the parasitic capacitance without increasing the distance between conductive patterns.
2Productivity
If the distance between adjacent conductive patterns is reduced, then device integration increases, but cross talk between conductive patterns increases
Solution Approach 1:
The air spacer serves as an electromagnetic intermediary that reduces the coupling between adjacent bit lines. By introducing this low-dielectric-constant layer, the electric field coupling and signal interference (cross talk) between closely-spaced conductive patterns is minimized while maintaining high device integration.
3Object-generated harmful factors
If a spacer with lower dielectric constant is formed between conductive patterns, then parasitic capacitance decreases, but device complexity increases
Solution Approach 1:
The air spacer structure is segmented into multiple portions: first air spacers positioned between bit lines and contact holes, second air spacers between bit lines and plug structures, and third air spacers between bit lines and upper interconnects. This segmentation allows the complex low-parasitic capacitance structure to be formed through modular, step-by-step fabrication processes.
Solution Approach 2:
Air spacers are selectively formed only in specific locations where parasitic capacitance reduction is most critical - between adjacent bit lines and at interfaces with contact structures. This local application of the low-dielectric-constant material optimizes the balance between reducing parasitic capacitance and minimizing overall device complexity.
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 effectively reduces bit line loading capacitance, thereby improving the bit line sensing margin and enhancing the performance of semiconductor devices, such as DRAM, by minimizing resistance characteristics and optimizing contact structure resistance.
Implementation Method 1
a parasitic capacitance between the bit lines may impede the flow of electrical signals... in order to reduce the parasitic capacitance between the adjacent conductive patterns, a spacer having a lower dielectric constant may be formed between the conductive patterns
Data Source
AI summary
Semiconductor devices are provided. The semiconductor devices may include a first interconnection structure and a second interconnection structure which are disposed on a semiconductor substrate. A contact structure may be disposed between the first and second interconnection structures. A first lower air spacer may be disposed between the first interconnection structure and the contact structure. A second lower air spacer may be disposed between the second interconnection structure and the contact structure to be spaced apart from the first lower air spacer. An upper air spacer may be disposed on side surfaces of the contact structure to be connected to the first and second interconnection structures.