Word Line Trench Depth Control to Reduce Semiconductor Leakage
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Solution Overview
Problem
The challenge of reducing leakage in highly integrated semiconductor structures due to close distances between components, which complicates the manufacturing process and affects process yield.
Innovation Solution
A method of forming first and second word line trenches with controlled depths in active and insulating areas, using mask layers to etch dielectric material uniformly, ensuring consistent etching rates and reducing leakage by controlling the depth of word line structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the pitch between semiconductor structures is shortened to improve integration, then device density is improved, but leakage increases due to close distances
Solution Approach 1:
The word line trench formation process is segmented into two distinct steps: first forming a deep trench in the active area, then forming a shallower trench extending through the insulating area. This segmentation allows different etching conditions to be optimized for each region, preventing leakage while maintaining high density.
Solution Approach 2:
Different etching depths are applied to different areas: the active area receives a deeper etch (first depth) while the insulating area receives a shallower etch (second depth). This local differentiation ensures proper electrical isolation in the insulating area while maintaining adequate depth in the active area for functional performance.
2Reliability
If the word line trench depth is increased to improve electrical performance, then device performance is improved, but manufacturing precision becomes more difficult to control
Solution Approach 1:
The etching process is divided into two separate etching operations with different depth targets. The first etching operation creates a deep trench in the active area, and the second etching operation creates a shallower trench through the insulating area. This segmentation makes depth control more manageable than a single deep etch would require.
Solution Approach 2:
The first word line trench is formed in advance before the second word line trench. This preliminary action establishes a reference structure that guides the subsequent etching process, ensuring consistent depth control across different areas.
3Ease of manufacture
If a single etching process is used for word line trench formation, then process simplicity is maintained, but etching depth uniformity across different materials deteriorates
Solution Approach 1:
The etching process is segmented into two distinct etching steps, each optimized for specific material regions. The first etching targets the active area with appropriate parameters, while the second etching targets the insulating area with adjusted parameters, ensuring uniform depth across different materials.
Solution Approach 2:
Different etching parameters are applied to different material regions: the active area undergoes etching with parameters optimized for that material, while the insulating area undergoes etching with parameters optimized for dielectric materials. This local optimization ensures consistent etching depth and quality across heterogeneous materials.
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
The method enables better control over the etching process, reducing leakage and improving the performance of semiconductor structures by ensuring uniform depth and consistency in word line trench formation.
Implementation Method 1
A first dielectric layer is deposited in the first word line trench and on the active area and the insulating area
Implementation Method 2
A first dielectric layer is deposited in the first word line trench and on the active area and the insulating area
Implementation Method 3
A second word line trench is formed in the active area and the insulating area through etching the first dielectric layer
Implementation Method 4
A second word line trench is formed in the active area and the insulating area through etching the first dielectric layer
Data Source
AI summary
A method of manufacturing a semiconductor structure is provided by embodiments of this disclosure, and the method includes the following steps. An insulating area and an active area are formed in a substrate. A first word line trench is formed in the active area. A first dielectric layer is deposited in the first word line trench and on the active area and the insulating area. A second word line trench is formed through etching the first dielectric layer. Besides, the second word line trench is linear and extends through the insulating area and the active area of the substrate, and a portion of the first dielectric layer is remained in a bottom of the second word line trench. Then, a word line structure is formed in the second word line trench. Moreover, a semiconductor structure is provided in this disclosure.