Stacked Conductive Plug Structure for Plug Alignment and Gap Reduction
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Solution Overview
Problem
The complexity of manufacturing semiconductor devices leads to integration challenges, including difficulties in filling high aspect ratio openings and misalignment issues between conductive plugs and dielectric layers, which can result in performance degradation and yield reduction.
Innovation Solution
A semiconductor device structure with stacked conductive plugs, where the top surface of the first conductive plug is greater than its bottom surface, and a silicide layer covering the upper portion of the first conductive plug, is used. This design enhances the landing area for the second conductive plug, reducing the risk of gap formation and misalignment by forming lateral extension portions with tapered widths and using liners to separate plugs from the substrate and dielectric layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional filling methods are used for high aspect ratio openings, then manufacturing complexity is reduced, but misalignment and gap formation occur between conductive plugs and dielectric layers
Solution Approach 1:
The patent transitions from a conventional vertical plug structure to a stacked conductive plug structure with lateral extensions. The first conductive plug includes upper lateral extension portions that protrude laterally into the first dielectric layer, creating a multi-dimensional configuration that provides both mechanical support and improved alignment tolerance for the second conductive plug.
Solution Approach 2:
The conductive interconnect structure is segmented into multiple distinct conductive plugs (first and second conductive plugs) with different functions and configurations. The first conductive plug serves as a support structure with lateral extensions, while the second conductive plug provides the primary electrical connection, allowing each segment to be optimized independently for its specific function.
2Manufacturing precision
If stacked conductive plugs with lateral extensions are used, then alignment precision and gap formation are improved, but manufacturing complexity increases
Solution Approach 1:
The first conductive plug with lateral extensions is formed in advance before the second conductive plug. The lateral extension portions protrude laterally into the first dielectric layer to provide a pre-positioned support structure and alignment reference for the subsequent formation of the second conductive plug, ensuring proper alignment before the final plug is deposited.
Solution Approach 2:
The second conductive plug is positioned directly over the first conductive plug, with the first plug's lateral extensions nested within the overall structure to provide support. The stacked configuration creates a nested arrangement where the first plug is partially contained within the vertical footprint of the second plug, optimizing space utilization.
3Ease of manufacture
If conductive plugs are directly formed in dielectric layers, then manufacturing process is simple, but gap formation and misalignment occur
Solution Approach 1:
The lateral extension portions of the first conductive plug protrude into the first dielectric layer to provide a cushioning support structure before the second conductive plug is formed. This pre-positioned support compensates for potential misalignment and prevents gap formation between the two plugs, ensuring reliable electrical connection and improving device yield.
4Adaptability or versatility
If conventional single-layer dielectric structure is used, then device structure is simple, but integration functionality is limited
Solution Approach 1:
The patent introduces a stacked conductive plug structure where the first conductive plug with lateral extensions and the second conductive plug are arranged in a multi-dimensional configuration. This vertical stacking with lateral extensions adds dimensional complexity that enables greater integration functionality and connectivity options within the semiconductor device.
Data Source
AI summary
A semiconductor device structure includes a first dielectric layer disposed over a semiconductor substrate, and a second dielectric layer disposed over the first dielectric layer. The semiconductor device structure includes a first dielectric layer disposed over a semiconductor substrate, and a second dielectric layer disposed over the first dielectric layer. The semiconductor device structure also includes a first conductive plug disposed in the first dielectric layer. An upper portion of the first conductive plug extends into the second dielectric layer. The semiconductor device structure further includes a silicide layer disposed in the second dielectric layer and covering a top surface and sidewalls of the upper portion of the first conductive plug, and a second conductive plug disposed in the second dielectric layer and directly over the first conductive plug and the silicide layer.