Uniform Grid Metal Gate and Trench Contact Cut Simplification
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Solution Overview
Problem
The challenge of maintaining mobility improvement and short channel control in microelectronic devices as device dimensions scale below the 10 nanometer node, particularly in multi-gate and nanowire transistors, is compounded by the constraints on lithographic processes used to pattern features, leading to a trade-off between critical dimension and spacing.
Innovation Solution
The implementation of a unified dielectric cut plug process for trench contacts and metal gate cuts, followed by selective reconnection or rejoining of isolated structures, simplifies the fabrication process and reduces process variation, using a 'plug-last' approach that avoids complex lithography and deposition steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional separate processes for trench contacts and metal gate cuts are used, then manufacturing flexibility is maintained, but process complexity and variation increase
Solution Approach 1:
The patent combines the trench contact cut and metal gate cut processes into a single unified dielectric cut plug process. A single etch process forms both the trench contact openings and the metal gate cuts simultaneously, eliminating the need for separate lithography and deposition steps. This merging of processes reduces process variation and simplifies fabrication while maintaining the required structural distinctions between trench contacts and metal gates.
2Productivity
If separate lithography processes are used for trench contacts and metal gates, then feature isolation is achieved, but process cost and time increase
Solution Approach 1:
The patent implements a single lithography process that patterns both trench contact and metal gate features simultaneously. The unified dielectric cut plug process uses one lithography step to define all subsequent etch regions, eliminating multiple sequential lithography operations. This significantly reduces fabrication time and process cost while maintaining precise feature isolation through the selective etching steps that follow.
3Manufacturing precision
If complex lithography and deposition steps are used, then feature precision is improved, but process cost increases
Solution Approach 1:
The patent replaces complex sequential lithography and deposition processes with a unified dielectric cut plug approach. A single lithography step defines all features, followed by a single etch process that creates both trench contact and metal gate openings. This eliminates multiple deposition and re-lithography steps, significantly reducing process cost while maintaining the precision required for sub-10nm device fabrication.
4Adaptability or versatility
If uniform grid structure is implemented across all regions, then manufacturing simplicity is achieved, but design flexibility is reduced
Solution Approach 1:
The patent implements a selective reconnection process that allows different regions of the uniform grid structure to have different electrical connectivity characteristics. After the unified etch process creates the dielectric cut plugs, selective regions are reconnected through additional processing steps. This enables design flexibility where trench contacts can be isolated or connected, and metal gates can be continuous or segmented, all while starting from a simple uniform grid pattern.
Data Source
AI summary
Integrated circuit structures having uniform grid metal gate and trench contact cut in select regions are described. A structure includes a dielectric sidewall spacer between a first gate electrode and a conductive trench contact. First and second parallel dielectric cut plug structures extend through the first gate electrode, through the dielectric sidewall spacer, and through the conductive trench contact. A second gate electrode is laterally spaced apart from the conductive trench contact at a side of the conductive trench contact opposite the first gate electrode. The first and second dielectric cut plug structures do not extend through the second gate electrode.