Word Line Air Gap Structure for Lower DRAM Parasitic Capacitance
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Solution Overview
Problem
As dynamic random access memory devices shrink and data storage speed increases, parasitic capacitance between conductive layers becomes a significant performance limiting factor.
Innovation Solution
A method for manufacturing a semiconductor device that involves forming trenches in a substrate with shallow trench isolation regions and active regions, depositing a word line conductive layer within these trenches, and creating an air gap structure in the insulating film by controlling step coverage, which reduces the overall dielectric constant and parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If device size is reduced and data storage speed is increased, then memory capacity and speed are improved, but parasitic capacitance between conductive layers increases and becomes more significant
Solution Approach 1:
The patent extracts the harmful dielectric material from the trench region and replaces it with an air gap structure. By removing the solid insulating film from the trench and retaining only the air gap, the parasitic capacitance between conductive layers is reduced while maintaining the word line conductive layer structure.
Solution Approach 2:
The patent introduces a porous air gap structure within the insulating layer. This air gap structure acts as a low-density, low-dielectric constant region that reduces parasitic capacitance while allowing the insulating layer to maintain its structural integrity and embedding function.
2Object-generated harmful factors
If air gap structure is formed by controlling step coverage of insulating film, then parasitic capacitance is reduced, but manufacturing process complexity increases
Solution Approach 1:
The patent changes the physical parameters of the insulating film deposition process, specifically controlling the step coverage parameter. By adjusting deposition conditions to achieve partial coverage rather than complete coverage, the air gap structure is formed naturally without requiring additional process steps.
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 air gap structure effectively reduces parasitic capacitance between the word line conductive layer and other conductive layers, thereby enhancing the performance parameters of the semiconductor device.
Implementation Method 1
reducing the overall dielectric constant of material between the word line conductive layer and other conductive layers
Data Source
AI summary
The method making a semiconductor device includes: providing a substrate having a shallow trench isolation region and an active region, patterned with trenches; and forming a word line conductive layer partly located in the trench; forming a first insulating film on the word line conductive layer, and forming an air gap structure in the trench in the first insulating film by controlling the step coverage of the first insulating film; removing the first insulating film from the substrate surface to form a first insulating layer, which embeds the air gap structure. The air gap structure in the first insulating layer on the word line conductive layer reduces the overall dielectric constant of the insulating material between the word line conductive layer and other conductive layers, so as to achieve the purpose of reducing the parasitic capacitance between the word line conductive layer and other conductive layers, thereby mitigating the influence of the parasitic capacitance on the device performance parameters.