Inspection Hole Striding Boundary for Semiconductor Plug Formation
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Solution Overview
Problem
The increasing integration and micronization of semiconductor devices make it difficult to determine if conductive plug holes are properly formed during in-line inspection, as conventional inspection methods only expose the diffusion or interconnect layers at the bottom of the inspection hole, making it hard to assess the hole's formation.
Innovation Solution
The semiconductor device includes inspection holes that extend from the diffusion or interconnect layers, with their openings positioned across the boundary of these layers, allowing for better visibility of the layer boundaries during in-line inspection, facilitating the assessment of proper hole formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the inspection hole is located on the diffusion layer or interconnect layer, then the inspection hole can be properly formed, but only a uniform image of the layer is exposed at the bottom of the inspection hole, making it difficult to decide whether the hole is properly formed
Solution Approach 1:
The inspection hole opening is strategically positioned to straddle the boundary between the diffusion layer and isolation region (or interconnect layer and insulating film), creating a local structural difference at the hole bottom. This boundary straddling configuration ensures that the bottom of the inspection hole exposes both the diffusion layer/interconnect layer and the isolation region/insulating film, generating a distinguishable image pattern that enables accurate inspection of hole formation while maintaining proper hole structure.
2Productivity
If the integration level and micronization of semiconductor devices are advanced, then device performance is improved, but it becomes more difficult to determine if conductive plug holes are properly formed during in-line inspection
Solution Approach 1:
The inspection hole opening is strategically positioned to straddle the boundary between the diffusion layer and isolation region (or interconnect layer and insulating film), creating a local structural difference at the hole bottom. This boundary straddling configuration ensures that the bottom of the inspection hole exposes both the diffusion layer/interconnect layer and the isolation region/insulating film, generating a distinguishable image pattern that enables accurate inspection of hole formation while maintaining proper hole structure.
Data Source
AI summary
The semiconductor device includes a semiconductor substrate, a diffusion layer, an interconnect layer, a contact plug, a contact-inspection hole, a via plug, and a via-inspection hole. Similarly to a contact plug hole, the contact-inspection hole extends from the diffusion layer to the interconnect layer. The opening of the contact-inspection hole on the side of the diffusion layer is disposed across the boundary of the diffusion layer. Also, similarly to a via plug hole, the via-inspection hole extends from an interconnect to an interconnect layer. The opening of the via-inspection hole on the side of the interconnect is disposed across the boundary of the interconnect.