Wrapping Stair Contact Structure for High-Density 3D Memory
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Solution Overview
Problem
The increasing demand for higher storage density in semiconductor devices, such as 3D memory, is hindered by complex manufacturing processes and rising costs, which are exacerbated by the limitations of process, device, and material constraints.
Innovation Solution
A semiconductor device with a stacked structure featuring a stair unit structure and a contact structure that penetrates through stair steps, allowing for efficient connection of gate layers, and a method of manufacturing involving alternating insulating dielectric and gate sacrificial layers to form a stacked structure with stair unit structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of stacked layers is increased to improve storage density, then storage density per unit area is improved, but the manufacturing process becomes more complex and manufacturing cost increases
Solution Approach 1:
The patent divides the manufacturing process into distinct modules: forming gate layers, forming stair unit structures, and forming contact structures. This segmentation allows each module to be optimized independently, simplifying the overall manufacturing process while maintaining high storage density through the stacked architecture.
Solution Approach 2:
The patent transitions from planar 2D memory structures to 3D stacked structures by introducing vertical stacking of gate layers and stair unit structures. This dimensional change enables significantly higher storage density per unit area while the modular design keeps manufacturing complexity manageable.
2Quantity of substance
If the number of stacked layers is increased to improve storage density, then storage density per unit area is improved, but manufacturing cost increases
Solution Approach 1:
The stair unit structure serves multiple functions: it provides structural support for stacked gate layers, creates necessary spacing for contact structures, and enables vertical integration. This multi-functionality reduces the need for additional specialized components and manufacturing steps, thereby controlling costs while achieving high storage density.
3Ease of manufacture
If stair unit structures with wrapping-around stair steps are used to connect gate layers, then manufacturing process is simplified, but structural complexity increases
Solution Approach 1:
Instead of creating complex three-dimensional curved contact structures that would follow the wrapping-around stair steps, the patent inverts the approach by forming contact structures that penetrate vertically through the stair steps. This inversion simplifies the contact structure fabrication while the stair unit structures themselves provide the necessary structural organization.
4Reliability
If contact structures penetrate through stair steps to connect gate layers, then electrical connection is improved, but manufacturing precision requirements increase
Solution Approach 1:
The stair unit structures are formed first, creating predefined vertical pathways and reference structures. Subsequently, contact structures are formed to align with these pre-established pathways, reducing the precision requirements compared to forming all structures simultaneously. The preliminary formation of stair steps acts as a template for contact structure alignment.
Data Source
AI summary
According to one aspect of the present disclosure, a semiconductor device is provided. The semiconductor device may include a stacked structure comprising gate layers stacked along a first direction. The semiconductor device may include a stair unit structure located in the stacked structure and comprising a plurality of wrapping-around stair steps. The semiconductor device may include a contact structure penetrating through the stair step along the first direction and connected with the gate layer.