MOSFET Gate Isolation Layout for Defect-Reduced Contact Etching
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Solution Overview
Problem
As semiconductor devices are scaled down, the integration of MOSFETs faces challenges in maintaining electrical properties due to the formation of gate cutting and separation structures, which can lead to pattern defects and decreased performance.
Innovation Solution
Simultaneously forming first and second isolation patterns as a single unitary body, ensuring they are substantially the same in width, top surface level, and height, facilitates easy etching of the lower dielectric layer to form contacts, thereby minimizing pattern defects and improving electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gate cutting and separation structures are formed to separate gate structures, then electrical properties are improved, but pattern defects increase and manufacturing complexity increases
Solution Approach 1:
The patent merges the formation of first isolation patterns and second isolation patterns into a single simultaneous process step. Both isolation patterns are formed as a unitary body from a single dielectric layer, eliminating the need for separate formation steps. This reduces pattern defects by avoiding multiple alignment operations while still achieving the necessary gate separation for good electrical properties.
Solution Approach 2:
The single dielectric layer serves multiple functions: it forms both the first isolation patterns that separate adjacent gate structures and the second isolation patterns that provide lateral isolation. This multi-functional approach simplifies the manufacturing process while maintaining the electrical performance benefits of gate separation.
2Reliability
If multiple isolation patterns are formed separately, then gate separation is achieved, but fabrication process complexity increases
Solution Approach 1:
The patent combines the formation of multiple isolation patterns into a single fabrication step. A single dielectric layer is deposited and patterned to create both first isolation patterns (for vertical gate separation) and second isolation patterns (for lateral isolation) simultaneously. This reduces fabrication process complexity while maintaining effective gate separation.
Solution Approach 2:
The isolation structure is segmented into first isolation patterns and second isolation patterns that serve different spatial functions. The first isolation patterns extend in a first direction to separate gate structures vertically, while the second isolation patterns extend in a second direction for lateral isolation. This segmentation allows each pattern type to be optimized for its specific function while being formed in a unified process.
3Adaptability or versatility
If isolation patterns are formed at different levels, then structural flexibility is increased, but etching precision requirements increase
Solution Approach 1:
The patent forms the first isolation patterns and second isolation patterns at substantially the same level within a single dielectric layer. This equipotential approach simplifies the etching process by providing a uniform etching plane, reducing the precision requirements compared to forming patterns at different levels. The single-level formation maintains structural flexibility while significantly easing manufacturing precision demands.
Data Source
AI summary
A semiconductor device including a substrate; gate structures spaced apart from each other on the substrate, each gate structure including a gate electrode and a gate capping pattern; source/drain patterns on opposite sides of the gate structures; first isolation patterns that respectively penetrate adjacent gate structures; and a second isolation pattern that extends between adjacent source/drain patterns, and penetrates at least one gate structure, wherein each first isolation pattern separates the gate structures such that the gate structures are spaced apart from each other, the first isolation patterns are aligned with each other, and top surfaces of the first and second isolation patterns are each located at a level the same as or higher than a level of a top surface of the gate capping pattern.