Aligned Trench Contact Plug Layout to Prevent Gate Shorts
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Solution Overview
Problem
As semiconductor devices become increasingly highly integrated, the shrinking area occupied by word line and bit line contact plugs poses challenges in preventing short defects between these components, necessitating improved manufacturing methods to enhance contact plug formation and reduce defects.
Innovation Solution
A method for manufacturing semiconductor devices involves forming contact holes, filling them with plug material, etching to create contact plugs, and forming gate insulation layers on the exposed side walls, which includes a trench aligned with the contact plug side walls, and partially filling the trench with a gate electrode, using oxide films to mitigate short defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the area occupied by contact plugs is shrunk to achieve higher integration, then productivity and device density are improved, but the risk of short defects between contact plugs and gate electrodes increases
Solution Approach 1:
An oxide film is introduced as an intermediary layer between the contact plug and the gate electrode. This oxide film acts as a protective barrier that prevents direct contact and potential shorting between the conductive contact plug and the gate electrode, thereby maintaining reliability while allowing for higher integration density
Solution Approach 2:
The oxide film is formed on the contact plug surface before the gate electrode is deposited. This preliminary oxidation step ensures that the protective barrier is in place prior to subsequent processing steps, preventing short defects from occurring during device operation
2Productivity
If the contact plug area is reduced for higher integration, then device density improves, but manufacturing precision requirements increase to prevent short defects
Solution Approach 1:
The oxide film serves as a robust intermediary layer that provides a clear visual and physical boundary between the contact plug and gate electrode. This makes it easier to control alignment and spacing during manufacturing, reducing the precision requirements for forming small contact plugs at high density
3Reliability
If oxide films are formed between contact plugs and gate electrodes to prevent short defects, then reliability improves, but device complexity increases
Solution Approach 1:
The oxide film formation step is merged with the existing gate electrode deposition process flow. By combining these steps into a unified manufacturing sequence, the additional complexity of forming oxide films is minimized while still achieving the reliability benefit of short defect prevention
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 reduces process difficulties in forming stable contact plugs and minimizes short defects between contact plugs and gate electrodes by aligning gate insulation layers with the contact plug side walls, enhancing the reliability and performance of semiconductor devices.
Implementation Method 1
forming a gate insulation layer on the exposed side wall of the contact plug and a surface of the trench
Data Source
AI summary
A method includes forming an inter-layer insulation layer on a substrate, forming a plug material penetrating the inter-layer insulation layer and contacting a portion of the substrate, forming a contact plug by etching the plug material, forming a trench exposing a side wall of the contact plug by etching the substrate and the inter-layer insulation layer to be aligned with a side wall of the contact plug, forming a gate insulation layer on a surface of the trench and the exposed side wall of the contact plug, and forming a gate electrode partially filling the trench on the gate insulation layer.