3D Semiconductor Device With Etch Stop Layer For Contact Plug Depth Control
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Solution Overview
Problem
Current semiconductor devices face challenges in achieving high integration levels necessary for meeting performance and cost requirements, particularly in the fabrication of three-dimensional semiconductor memory devices where maintaining high integration while managing varying thicknesses and etch selectivity across different regions is complex.
Innovation Solution
The solution involves a semiconductor device structure with a substrate having distinct regions, a lower layer structure with varying thicknesses, an etch stop layer with specific selectivity, and contact plugs that connect electrode layers across these regions, allowing for precise etching and layer formation to enhance integration. This includes the use of an amorphous boron layer for etch selectivity and isotropic etching processes to create stepped structures and contact plugs with varying depths and widths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a lower layer structure with varying thicknesses is used to achieve high integration, then integration density is improved, but etch selectivity management becomes more complex
Solution Approach 1:
An etch stop layer is introduced as an intermediary between the lower layer structure and upper layer structure. This etch stop layer has specific etch selectivity relationships with both adjacent layers, enabling precise control of etching depths to reach different electrode layers in different regions while managing the complexity of varying thicknesses.
Solution Approach 2:
The lower layer structure is designed with different thicknesses in different regions (first region and second region), allowing local optimization where the structure is thicker in regions requiring deeper etching to reach specific electrode layers, thereby achieving high integration density while maintaining etch selectivity through the intermediary etch stop layer.
2Adaptability or versatility
If contact plugs with varying depths are formed to connect different electrode layers, then layer connectivity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The etch stop layer serves as a reference intermediary that enables formation of contact plugs with different depths. By controlling etching to stop at the etch stop layer or through it to specific electrode layers, the patent achieves versatile layer connectivity while managing manufacturing precision through the etch selectivity relationship between the etch stop layer and adjacent layers.
3Productivity
If a stepped structure is created in the connection region, then integration efficiency is improved, but structural complexity increases
Solution Approach 1:
The lower layer structure is segmented into different thickness regions (first region and second region), creating a stepped structure in the connection region. This segmentation allows different areas to be optimized for their specific functions, improving integration efficiency while the etch stop layer provides a unifying reference that manages the overall structural 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 approach enables the fabrication of highly integrated three-dimensional semiconductor devices with improved etch selectivity and structural precision, enhancing the integration density and performance of memory devices by allowing for efficient contact plug formation and layer connectivity across varying thicknesses.
Implementation Method 1
the etch stop layer having an etch selectivity with respect to both the upper layer structure and the lower layer structure
Implementation Method 2
the amorphous boron layer having an etch selectivity with respect to both the upper layer structure and the lower layer structure
Data Source
AI summary
Provided is a semiconductor device including a lower layer structure on a substrate, the lower layer structure having different thicknesses on first and second regions of the substrate, the lower layer structure including an electrode layer at a top and an insulating layer thereunder, an etch stop layer on the lower layer structure, an upper layer structure on the etch stop layer, the etch stop layer having an etch selectivity to the upper and lower layer structures, first and second contact plugs filling first and second openings defined in the upper layer structure and the etch stop layer on the first and second regions, respectively, and contacting corresponding electrode layers of the lower layer structure, respectively, such that one of the first and second contact plugs downwardly extends further with respect to a bottom of the etch stop layer than the other one of the first and second contact plugs.