Semiconductor Wiring Air Gaps Beyond Metal Line Layout Limits
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Solution Overview
Problem
Existing semiconductor devices cannot form air gaps in regions without metallic wiring lines, limiting the flexibility and density of air gap formation in relation to metallic wiring layouts.
Innovation Solution
A semiconductor device structure where a first and second wiring layer with metallic films are stacked via a diffusion preventing film, which includes a first film and a second film buried in holes, allowing air gaps to be formed with an opening width equal to or greater than the holes, enabling air gap formation in any desired region regardless of wiring layouts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If air gaps are formed in insulating layer portions interposed between metallic wiring lines, then wiring capacitance is reduced, but the region in which air gaps can be formed is limited to areas with metallic wiring lines
Solution Approach 1:
The diffusion preventing film is segmented into a first film and a second film with holes, allowing the air gap opening to be decoupled from the metallic wiring line pattern. This segmentation enables independent control of air gap formation regions from wiring line locations, resolving the contradiction by allowing air gaps to be formed in regions without metallic wiring lines while still achieving capacitance reduction benefits
Solution Approach 2:
The invention introduces a vertical dimension separation between the metallic wiring lines (in planar regions) and the air gaps (which can extend vertically through the diffusion preventing film structure). The air gap opening width can be equal to or greater than the hole opening width, allowing air gaps to protrude laterally beyond the wiring line footprint, enabling air gap formation in regions without metallic wiring lines
2Reliability
If a diffusion preventing film is formed to prevent metallic film diffusion, then reliability is improved, but device structure becomes more complex
Solution Approach 1:
The diffusion preventing film incorporates a porous structure with holes formed in the first film and filled with the second film. This porous configuration provides effective diffusion barrier functionality while allowing the air gap structure to be formed through the same film layer, reducing overall device complexity compared to completely solid diffusion preventing films
Solution Approach 2:
The diffusion preventing film serves multiple functions: it prevents metallic film diffusion, provides a template for hole formation, and enables air gap structure creation. The first film and second film combination achieves both diffusion prevention and air gap formation capabilities in a single integrated structure, reducing the need for separate components and simplifying the overall device architecture
Data Source
AI summary
Provided are a semiconductor device in which an air gap structure can be formed in any desired region regardless of the layout of metallic wiring lines, a method for manufacturing the semiconductor device, and an electronic apparatus. A first wiring layer and a second wiring layer including a metallic film are stacked via a diffusion preventing film that prevents diffusion of the metallic film. The diffusion preventing film is formed by burying a second film in a large number of holes formed in a first film. At least the first wiring layer includes the metallic film, an air gap, and a protective film formed with the second film on the inner peripheral surface of the air gap, and the opening width of the air gap is equal to the opening width of the holes formed in the first film or is greater than the opening width of the holes.