Gate Contact Isolation Liner for Vertical Erosion Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As semiconductor devices shrink, the risk of short circuits between gate contacts and source-drain regions increases due to reduced gate height and misalignment, affecting product yield and reliability.
Innovation Solution
Forming an isolation liner above the gate spacers before depositing the gate cap to prevent vertical erosion and electrically isolate the gate contact from the source-drain region, using techniques like atomic layer deposition and selective etching to create a barrier during contact hole formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If device scaling is performed to reduce gate size, then manufacturing precision and integration density improve, but the risk of short circuits between gate contacts and source-drain regions increases
Solution Approach 1:
An isolation liner is introduced as an intermediary material between the gate contact and the source-drain region. This liner acts as a protective barrier that prevents direct contact and potential short circuits, while allowing the gate contact to maintain its electrical connection to the gate structure. The isolation liner is deposited conformally on the gate spacer and extends into the contact hole, creating a controlled interface that eliminates the harmful direct interaction between conductive elements.
Solution Approach 2:
The gate spacer is recessed below the gate structure height before forming the contact hole. This preliminary action creates a recessed region that will later accommodate the isolation liner, ensuring that the liner is positioned correctly to prevent vertical erosion and provide electrical isolation. By preparing the spacer geometry in advance, the subsequent contact hole formation and liner deposition are facilitated, and the risk of misalignment is reduced.
2Speed
If gate height is reduced to improve device performance, then switching speed improves, but vertical erosion during contact hole formation increases
Solution Approach 1:
The gate spacer is recessed below the gate structure height before forming the contact hole. This preliminary action creates a recessed region that will later accommodate the isolation liner, ensuring that the liner is positioned correctly to prevent vertical erosion and provide electrical isolation. By preparing the spacer geometry in advance, the subsequent contact hole formation and liner deposition are facilitated, and the risk of misalignment is reduced.
Solution Approach 2:
The isolation liner serves as a mediator that protects the gate spacer from vertical erosion during contact hole formation. By depositing the liner on the recessed spacer, the etching process is constrained, and the gate structure maintains its dimensional integrity despite the reduced gate height that enables faster switching.
3Area of stationary object
If gate contact is placed closer to source-drain region to improve integration density, then device compactness improves, but electrical isolation becomes more difficult
Solution Approach 1:
The isolation liner is deposited conformally on the gate spacer and extends into the contact hole, creating a controlled interface that eliminates the harmful direct interaction between conductive elements. This liner acts as a protective barrier that prevents direct contact and potential short circuits, while allowing the gate contact to maintain its electrical connection to the gate structure.
Solution Approach 2:
The isolation liner provides localized electrical insulation precisely where needed - at the interface between the gate contact and source-drain region. By applying the insulating material only in the critical isolation zones rather than throughout the entire structure, the design achieves effective electrical separation while maintaining compact dimensions and allowing close placement of contacts.
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 method effectively reduces the likelihood of short circuits, enhances device performance, and increases product yield and reliability by preventing gate contact misalignment and erosion.
Implementation Method 1
An isolation liner may be deposited above the gate spacers and the first conductive material
Implementation Method 2
A portion of the isolation liner may be removed so that a top surface of the first conductive material is exposed
Data Source
AI summary
A method of forming a semiconductor structure includes forming a gate structure having a first conductive material above a semiconductor substrate, gate spacers on opposing sides of the first conductive material, and a first interlevel dielectric (ILD) layer surrounding the gate spacers and the first conductive material. An upper portion of the first conductive material is recessed. The gate spacers are recessed until a height of the gate spacers is less than a height of the gate structure. An isolation liner is deposited above the gate spacers and the first conductive material. A portion of the isolation liner is removed so that a top surface of the first conductive material is exposed. A second conductive material is deposited in a contact hole created above the first conductive material and the gate spacers to form a gate contact.