Landing Pad Air-Gap Structure for Plug Misalignment and Capacitance
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Solution Overview
Problem
The complexity of manufacturing semiconductor devices leads to issues such as poor electrical interconnection due to misalignment between upper and lower conductive features, necessitating improved manufacturing processes to enhance integration and reduce parasitic capacitance.
Innovation Solution
A semiconductor device design featuring a landing pad structure over lower plugs with an air gap below, formed by a method that includes creating a dielectric layer with protruded surfaces, performing a heat treatment to form the landing pads, and depositing a second dielectric layer to enclose the air gap, which reduces misalignment and parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If manufacturing complexity is increased to improve integration, then device functionality is improved, but misalignment between conductive features occurs leading to poor electrical interconnection
Solution Approach 1:
A dielectric layer is introduced as an intermediary structure between upper and lower conductive features. This dielectric layer includes a recess that receives and positions the lower conductive feature, acting as a mediator that ensures proper alignment and electrical connection while accommodating manufacturing variations.
Solution Approach 2:
The dielectric layer with its recess structure is formed in advance before the upper conductive features are deposited. This preliminary formation of the recess structure provides a pre-defined alignment reference that guides subsequent manufacturing steps, ensuring that upper conductive features align correctly with lower ones.
2Ease of manufacture
If conventional manufacturing processes are used, then manufacturing simplicity is maintained, but parasitic capacitance increases reducing device performance
Solution Approach 1:
Material is removed from the dielectric layer to form a recess, extracting unnecessary dielectric material that would otherwise be present between conductive features. This extraction reduces the parasitic capacitance while the recess structure itself is formed using standard semiconductor manufacturing techniques, maintaining ease of manufacture.
3Manufacturing precision
If alignment tolerance is reduced to improve connection precision, then electrical interconnection quality is improved, but manufacturing complexity increases
Solution Approach 1:
The dielectric layer with recess creates a structure where the lower conductive feature is positioned in a potential well (the recess), providing a self-aligning mechanism. This equipotential approach ensures that even with manufacturing variations, the conductive features maintain proper alignment and electrical connection without requiring complex alignment processes.
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 misalignment and parasitic capacitance, thereby increasing the yield rate and improving overall device performance by providing a larger landing area for upper plugs and enclosing an air gap between lower plugs.
Implementation Method 1
performing a heat treatment process to form a first landing pad over the top surface and the upper sidewalls of the first lower plug
Data Source
AI summary
A semiconductor device includes a first lower plug and a second lower plug disposed over a semiconductor substrate. The semiconductor device also includes a first landing pad disposed over a top surface and upper sidewalls of the first lower plug, and a first upper plug disposed over the first landing pad and electrically connected to the first lower plug. A width of the first lower plug is greater than a width of the first upper plug. The semiconductor device further includes a dielectric layer disposed over the semiconductor substrate. The first lower plug, the second lower plug, the first landing pad and the first upper plug are disposed in the dielectric layer, and the dielectric layer includes an air gap disposed between the first lower plug and the second lower plug.