Stepped Source/Drain Contact Structure Around Gate Separation Patterns
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Solution Overview
Problem
As demands for high performance, high speed, and multi-functionality of semiconductor devices increase, there is a need for improved integration and reliability, particularly in manufacturing fine-patterned semiconductor devices and overcoming limitations in operating characteristics due to size reductions of planar metal oxide semiconductor field-effect transistors (MOSFETs).
Innovation Solution
A semiconductor device is designed with a substrate, an active region, a gate structure, source/drain regions, a separation pattern, and a contact structure. The contact structure includes a first portion contacting the separation pattern and a second portion contacting the source/drain region, with a lower surface of the second portion being at a level lower than the lower surface of the first portion, and the lowermost end of the contact structure is spaced apart from the separation pattern. This configuration enhances integration and reliability by optimizing the contact structure's connection to the source/drain region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact structure is designed with a stepped configuration to improve electrical connection to the source/drain region, then the electrical conductivity and reliability are improved, but the manufacturing complexity and process difficulty increase
Solution Approach 1:
The contact structure is divided into multiple portions (first portion, second portion, third portion) with different lateral positions and depths, creating a stepped configuration. Each portion contacts the separation pattern at different locations, enabling progressive electrical connection through the insulating layer to the source/drain region while managing stress distribution.
Solution Approach 2:
The contact structure extends in the vertical dimension with varying depths for different portions, and in the lateral dimension with different horizontal positions. This multi-dimensional stepped design allows the contact structure to navigate through the insulating layer at different levels, improving electrical connection reliability while providing stress relief pathways.
2Reliability
If the contact structure extends deeper to improve electrical connection to the source/drain region, then the electrical conductivity is improved, but the risk of damaging the separation pattern and gate structure increases
Solution Approach 1:
The separation pattern is formed to extend through the insulating layer before the contact structure is created. This preliminary formation establishes a protective pathway and defines the routing, allowing the contact structure to be subsequently formed along predetermined safe paths that avoid critical regions of the separation pattern and gate structure.
Solution Approach 2:
The insulating layer serves as an intermediary medium between the contact structure and the separation pattern. By controlling the thickness and material properties of this insulating layer, the contact structure can penetrate through it to reach the source/drain region while the insulating layer provides cushioning and protection against direct contact that could damage the separation pattern.
3Reliability
If the contact structure is designed with a stepped configuration to provide stress relief, then the mechanical reliability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
Different portions of the contact structure have different local qualities in terms of depth, lateral position, and stress distribution characteristics. The first portion may be shallower and positioned to contact upper regions, while the second portion extends deeper to contact lower regions, with each portion optimized for its specific local mechanical and electrical requirements.
Solution Approach 2:
The contact structure utilizes parameter changes in depth, lateral position, and material composition across different portions. By varying these parameters, the stepped configuration achieves stress relief through gradual transitions rather than abrupt changes, reducing manufacturing precision requirements while maintaining mechanical reliability.
Data Source
AI summary
A semiconductor device includes: a substrate; an active region extending in a first direction on the substrate; a gate structure extending in a second direction on the active region and intersecting the active region; a source/drain region on the active region on a side of the gate structure; a separation pattern extending in the first direction and separating the gate structure; and a contact structure on the separation pattern and crossing the separation pattern, the contact structure being electrically connected to the source/drain region, wherein the contact structure includes a first portion and a second portion, the first portion contacts the separation pattern, the second portion contacts the source/drain region, a lower surface of the second portion is at a level lower than a lower surface of the first portion, and a lowermost end of the contact structure is spaced apart from the separation pattern.