Semiconductor Cell Region Layout for Lifting Prevention
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Solution Overview
Problem
In semiconductor devices, the outermost cell region patterns often suffer from incomplete shape formation and lifting phenomena due to optical diffraction or interference, leading to inadequate transfer of second active regions and potential electrical connections between bit lines and gate lines.
Innovation Solution
The solution involves a cell region layout with alternately aligned first and third active regions in the outermost portion, where the second active regions have different shapes, and forming insulating layers instead of contact pads to prevent electrical connections, ensuring proper active region formation and preventing lifting and bridge phenomena.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If various resolving power technology such as phase shift method or modified illumination method is employed to form fine patterns, then manufacturing precision is improved, but optical diffraction or interference occurs at the outermost portion of the cell region causing pattern transfer failure
Solution Approach 1:
The invention divides the outermost cell region into two distinct portions: a first outermost portion with complete-shaped active regions and a second outermost portion with incomplete-shaped active regions. This segmentation allows different pattern formation strategies to be applied to different areas, ensuring reliable pattern transfer in the first portion while accommodating the inherent optical limitations in the second portion.
Solution Approach 2:
The invention applies different design rules to different portions of the outermost cell region. The first outermost portion uses complete-shaped active regions with standard design rules to ensure proper pattern transfer, while the second outermost portion uses incomplete-shaped active regions that are specifically designed to prevent lifting phenomena. This local differentiation optimizes each area for its specific requirements.
2Reliability
If second active regions with smaller size are formed at the outermost portion to accommodate optical limitations, then lifting phenomenon is prevented, but incomplete shape formation occurs and pattern cannot be transferred appropriately
Solution Approach 1:
The invention segments the outermost cell region into two portions with different active region configurations. The first outermost portion contains complete-shaped active regions that can be properly transferred, while the second outermost portion contains incomplete-shaped active regions with smaller sizes that prevent lifting. This segmentation resolves the contradiction by providing appropriate solutions for each specific area.
Solution Approach 2:
Instead of attempting to form complete-shaped active regions in the second outermost portion where optical diffraction causes lifting, the invention inverts the approach by deliberately designing incomplete-shaped active regions. This inversion accepts the optical limitations and designs around them, transforming a potential failure mode into a deliberate design feature.
3Productivity
If conventional layout is used at the outermost portion, then device integration is maintained, but electrical connection between bit lines and gate lines may occur due to improper contact pad formation
Solution Approach 1:
The invention extracts the contact pad formation step from the outermost portion of the cell region. By deliberately not forming contact pads in this area, the invention prevents the potential electrical connection between bit lines and gate lines that would occur with conventional contact pad formation, while maintaining device integration elsewhere.
Solution Approach 2:
The invention introduces an insulating layer as an intermediary in the outermost portion where contact pads would normally be formed. This insulating layer acts as a mediator that prevents electrical connection between bit lines and gate lines, ensuring proper electrical isolation while maintaining the structural integrity and device integration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures accurate and reliable formation of active regions and contact pads, preventing lifting and bridge phenomena, thus enhancing the structural integrity and electrical isolation in the semiconductor device.
Implementation Method 1
a pattern may be transferred at the outermost portion of a cell region with an undesirable result due to optical diffraction or interference
Implementation Method 2
a pattern may be transferred at the outermost portion of a cell region with an undesirable result due to optical diffraction or interference
Data Source
AI summary
A cell region layout of a semiconductor device formed by adding active regions in the outermost portion of a cell region, and a method of forming a contact pad using the same are provided. The layout and the method include a first active region formed at the outermost portion of the cell region, and having the same shape as that of an inner active region located inwardly from the outermost portion of the cell region, and a third active region formed by adding at least two second active regions having shapes different from that of an inner active region. Further, an insulating layer fills a portion below a bit line passing the third active region. A lifting phenomenon occurring where an active region is not formed can be prevented by adding the active regions at the outermost portion of the cell region, and a bridge phenomenon occurring when bit lines or a bit line contact and a gate line electrically contact can be suppressed by filling a portion below a bit line with an insulating layer.