SRAM Unit Cell Layout With Cut Gate Electrodes for Dense Routing
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Solution Overview
Problem
Existing semiconductor devices face challenges in improving circuit performance and reliability due to issues such as metal filling problems, increased routing resistance, parasitic capacitance, short circuits, leakage, alignment margin reduction, and decreased packing density, particularly in SRAM unit cells with narrow active patterns and shrinking metal wiring.
Innovation Solution
A semiconductor device design featuring a conductive line structure that serves as connection wiring, with gate electrodes cut to improve SRAM unit cell performance, including specific arrangements of conductive lines, active patterns, and gate electrodes to enhance operational characteristics and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If metal wiring is shrunk to smaller feature size to improve circuit routing density, then routing density is improved, but metal filling problems, increased routing resistance, and reliability issues occur
Solution Approach 1:
The gate electrode is segmented into multiple sections by conductive line structures that extend through it, creating isolated conductive regions. This segmentation allows for better control of metal filling while maintaining routing density, as the conductive lines can be independently optimized for different functional requirements.
Solution Approach 2:
Different regions of the gate electrode are given different properties by introducing conductive line structures at specific locations. The conductive lines create localized regions with enhanced conductivity and different electrical characteristics, allowing optimization of routing resistance and filling in critical areas while maintaining overall device performance.
2Productivity
If device size is reduced to increase packing density, then packing density is improved, but alignment margin is reduced and device performance deteriorates
Solution Approach 1:
The conductive line structures extend in a direction transverse to the gate electrode length, utilizing the width dimension of the gate electrode. This dimensional approach allows conductive lines to be positioned without affecting the longitudinal alignment critical for device performance, thereby maintaining alignment margins while increasing packing density.
Solution Approach 2:
The conductive line structures serve as intermediary elements between different functional regions of the device. These intermediaries facilitate electrical connections and signal routing without requiring precise alignment with the main gate electrode, thus reducing the impact of alignment variations on device performance.
3Reliability
If gate electrode is cut by conductive line structure to improve SRAM performance, then operational characteristics are improved, but device complexity increases
Solution Approach 1:
The conductive line structures serve multiple functions simultaneously: they segment the gate electrode to improve SRAM operational characteristics, provide additional routing paths, and create isolated conductive regions for optimized signal distribution. This multi-functionality reduces the need for separate structures, thereby limiting the increase in device complexity.
Solution Approach 2:
The conductive line structures are merged with the gate electrode formation process, combining what could be separate fabrication steps into a unified structure. The conductive lines and gate electrode are formed as an integrated system, reducing overall device complexity compared to having separate independent structures.
Data Source
AI summary
A semiconductor device includes a substrate having first and second surfaces, first to third conductive line structures disposed on the first surface, extending in a first direction, and spaced apart from each other in a second direction, and a SRAM unit cell disposed on the first surface, and including first and second inverters connected to each other, a first pass transistor connected to the first inverter, a second pass transistor connected to the second inverter, a first gate electrode included in the first inverter, and a second gate electrode included in the first pass transistor, the first inverter and the first pass transistor are disposed between the first and third conductive line structures, the second inverter and the second pass transistor are disposed between the second and third conductive line structures, and the first and second gate electrodes are disposed between the first and third conductive line structures.