Semiconductor Contact Structure Trench Opening Design
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Solution Overview
Problem
The semiconductor industry faces challenges in forming reliable semiconductor devices at increasingly smaller sizes due to the complexity and difficulty of fabrication processes as feature sizes decrease, leading to high contact resistance and reduced operation speed.
Innovation Solution
A semiconductor device structure is formed with low contact resistance by creating an enlarged contact area through the formation of trenches and openings, allowing for a broadened contact area between conductive contacts and source/drain or gate structures, using a conductive material layer to fill these features, which reduces contact resistance and enhances device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency increases and costs decrease, but fabrication process complexity increases and manufacturing difficulty increases
Solution Approach 1:
The contact structure is segmented into multiple portions (first portion in the trench, second portion in the opening) with different cross-sectional areas. This segmentation allows each portion to be optimized independently for its specific function, simplifying the overall manufacturing process by breaking down the complex contact formation into manageable steps.
Solution Approach 2:
The contact structure transitions from a two-dimensional planar contact to a three-dimensional multi-port ion contact by adding vertical depth (trench) and lateral extension (opening). This dimensional change increases the total contact area without increasing the lateral footprint, enabling better electrical connection at scaled dimensions.
2Length of stationary object
If feature sizes continue to decrease to increase functional density, then geometric size decreases, but contact resistance increases
Solution Approach 1:
By adding the vertical dimension through the trench structure and extending laterally through the opening, the contact area is significantly increased without increasing the overall device footprint. This multi-port ion configuration provides a larger effective contact area that reduces contact resistance despite smaller geometric dimensions.
Solution Approach 2:
The contact structure uses a composite configuration combining different portions with different cross-sectional areas, where the first portion has a larger cross-section for current collection and the second portion has a smaller cross-section for precise alignment. This composite structure optimizes both electrical performance and manufacturability.
3Length of stationary object
If feature sizes continue to decrease to increase functional density, then geometric size decreases, but operation speed decreases
Solution Approach 1:
The multi-port ion contact structure adds vertical and lateral dimensions to the contact path, creating multiple parallel current paths. This increases the effective contact area and reduces contact resistance, thereby improving carrier transport efficiency and operation speed despite smaller geometric dimensions.
4Length of stationary object
If conventional contact structures are used at smaller sizes, then device size decreases, but contact resistance increases and reliability decreases
Solution Approach 1:
The contact is divided into multiple segments (first portion and second portion) with different functions. The first portion in the trench provides a large cross-sectional area for low contact resistance, while the second portion in the opening provides precise alignment. This segmented approach maintains reliability at smaller device sizes.
Solution Approach 2:
By utilizing the vertical dimension through the trench and the lateral dimension through the opening, the contact structure achieves a large effective contact area without increasing the device footprint. This multi-dimensional approach resolves the conflict between small device size and low contact resistance.
Data Source
AI summary
Structures and formation methods of a semiconductor device structure are provided. The semiconductor device structure includes a fin structure over a semiconductor substrate. The semiconductor device structure also includes an isolation feature over the semiconductor substrate. The fin structure is surrounded by the isolation feature. The semiconductor device structure further includes a gate stack covering the fin structure. In addition, the semiconductor device structure includes a source or drain (S/D) structure covering the fin structure. The semiconductor device structure also includes a conductive contact connected to the S/D structure. The conductive contact includes a first portion and a second portion. The second portion extends from the first portion to the S/D structure. The first portion has a first width adjoining the second portion. The second portion has a second width greater than the first width.