Semiconductor Bit Line Contact Geometry for Resistance Reduction
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Solution Overview
Problem
The scaling down of semiconductor devices poses challenges in achieving improved quality, yield, performance, and reliability while reducing complexity, particularly in the design of bit line contacts which affect contact resistance and overall device performance.
Innovation Solution
A semiconductor device design featuring bit line structures with specific geometries and top contacts that increase contact areas, including a first bit line structure with a first line portion and a second line portion arranged in perpendicular directions, and corresponding bit line top contacts with bar portions, which are electrically coupled with conductive layers to reduce contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact area between bit line structure and top contact is increased, then contact resistance is reduced, but device complexity increases
Solution Approach 1:
The bit line structure is divided into multiple segments (first line portion and second line portion) that are arranged in a stepped configuration. This segmentation allows the contact area to be increased through multiple contact points while maintaining a compact overall structure, thereby reducing contact resistance without proportionally increasing device complexity.
Solution Approach 2:
The bit line structure transitions from a two-dimensional planar contact to a three-dimensional stepped structure. The first line portion is positioned at a first level and the second line portion is positioned at a second level, creating vertical stacking that increases contact area in the vertical dimension while maintaining a compact footprint, thus reducing contact resistance without significantly increasing planar device complexity.
2Productivity
If the bit line structure is scaled down, then device density is improved, but manufacturing precision requirements increase
Solution Approach 1:
The bit line structure is segmented into multiple portions positioned at different levels, which allows the overall structure to be scaled down in footprint while maintaining adequate contact areas. Each segment can be independently formed and aligned, reducing the cumulative alignment precision requirements compared to a single large contact structure.
Solution Approach 2:
By utilizing vertical stacking with the first line portion at a first level and the second line portion at a second level, the structure achieves higher device density in the vertical dimension. This three-dimensional arrangement reduces the planar footprint and allows scaling down without proportionally increasing lateral alignment precision requirements, as contacts are formed at different vertical levels.
Data Source
AI summary
The present application discloses a semiconductor device and a method for fabricating the semiconductor device. The semiconductor device includes a substrate; a first bit line structure positioned above the substrate and including a first line portion arranged in parallel to a first direction, and a second line portion connecting to a first end of the first line portion and arranged in parallel to a second direction in perpendicular to the first direction; a first bit line top contact including a first bar portion positioned on the first end of the first line portion and arranged in parallel to the first direction, and a second bar portion connecting to a first end of the first bar portion, positioned on the second line portion, and arranged in parallel to the second direction; and a first top conductive layer electrically coupled to the first bit line top contact.