Self-Aligned Active Regions in Planar Transistor Architecture
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Solution Overview
Problem
Current semiconductor manufacturing techniques for forming active regions in planar transistor elements require multiple complex lithography processes, leading to increased costs, variability, and reduced scalability due to overlay errors and lithography-induced variations, especially in densely packed device areas like static RAM cells.
Innovation Solution
The method involves using a single critical lithography process to define initial mask features, followed by deposition and etch techniques to achieve self-aligned active regions with precise width dimensions and pitches, reducing the reliance on overlay alignment and enhancing controllability through atomic layer deposition and etch processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple complex lithography processes are used to form active regions, then manufacturing precision can be maintained, but device complexity and manufacturing costs increase significantly
Solution Approach 1:
The patent segments the formation of active regions by laterally separating source and drain regions through selective etching of sacrificial semiconductor material. This segmentation allows each region to be formed independently with precise dimensional control, eliminating the need for multiple complex lithography processes while maintaining manufacturing precision.
2Manufacturing precision
If multiple lithography processes are used, then active region dimensions can be controlled, but overlay errors and lithography-induced variations increase
Solution Approach 1:
The patent employs self-aligned formation where the gate electrode structure automatically defines the precise pitch and positioning of source and drain regions. The sacrificial material is positioned relative to the gate, and selective removal creates active regions with controlled pitch without requiring additional lithography alignment steps, thereby eliminating overlay errors and reducing dimensional variability.
3Ease of manufacture
If conventional lithography techniques are used, then manufacturing processes are established, but scalability is reduced due to overlay errors
Solution Approach 1:
The patent transitions from two-dimensional planar lithography patterning to three-dimensional self-aligned formation using vertically stacked sacrificial semiconductor layers. By utilizing the vertical dimension for material deposition and selective lateral etching, the method achieves scalable active region formation with precise dimensional control independent of lithography resolution limits, enabling continued scaling as device dimensions decrease.
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 significantly reduces manufacturing costs and variability, enabling higher packing density and scalability by achieving precise dimensions and pitches in active regions, such as those in static RAM cells, while minimizing lithography-induced errors.
Implementation Method 1
at least a portion of the sacrificial semiconductor material is removed to laterally separate the source region from the drain region
Implementation Method 2
gate electrode structure formed over a channel region
Data Source
AI summary
Active regions for planar transistor architectures may be patterned in one lateral direction, i.e., the width direction, on the basis of a single lithography process, followed by deposition and etch processes, thereby providing multiple width dimensions and multiple spaces or pitches with reduced process variability due to the avoidance of overlay errors typically associated with conventional approaches when patterning the width dimensions and spaces on the basis of a sequence of sophisticated lithography processes. Consequently, increased packing density, enhanced performance and reduced manufacturing costs may be achieved on the basis of process techniques as disclosed herein.