Direction-Specific Trimming for FinFET Contact Patterning
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Solution Overview
Problem
Conventional lithography and patterning techniques fail to meet the stringent End to End (ETE) critical dimension (CD) control requirements for contact landing in FinFET devices, particularly in three-dimensional transistor devices like FinFETs, which are essential for maintaining device performance and efficiency.
Innovation Solution
A direction-specific trimming process using neutral ion beam physical etching with a specific tilt angle is employed to enlarge the contact opening in the Y-direction while maintaining its size in the X-direction, ensuring all fin structures can make electrical connections with the contact and maintaining small critical dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional lithography and patterning techniques are used, then the manufacturing process is simple, but the critical dimension control for contact landing is insufficient
Solution Approach 1:
The patterning process is divided into multiple stages: initial contact opening formation, spacer deposition, and directional trimming. Each stage performs a specific function to progressively achieve the final precise contact dimensions, breaking down the complex precision requirement into manageable steps
Solution Approach 2:
The trimming process applies directional etching that selectively removes material from specific regions (sidewalls of spacers) while preserving other regions. This local selective removal enables precise control of contact dimensions in critical areas without affecting the entire structure
Solution Approach 3:
The patent introduces a vertical dimension component to the trimming process by using angled ion beam incidence. Instead of only horizontal etching, the angled approach allows selective removal of spacer material from lateral surfaces, adding a dimensional aspect that enables precise contact opening control
2Reliability
If the contact opening is enlarged to ensure all fin structures can connect, then contact reliability improves, but critical dimension control deteriorates
Solution Approach 1:
The directional trimming selectively enlarges the contact opening in specific directions where fin structures require connection, while maintaining tight dimensional control in other directions. This local selective enlargement ensures reliability where needed without compromising overall critical dimension precision
Solution Approach 2:
The trimming process applies a controlled excessive removal of spacer material that slightly over-enlarges the contact opening, then uses precise directional control to limit the enlargement only where necessary. This partial excessive action ensures all fins connect while minimizing impact on critical dimensions
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 approach improves contact overlay control and ensures all fin structures can make electrical connections, maintaining small critical dimensions and feature sizes, thereby enhancing the performance and efficiency of FinFET devices.
Implementation Method 1
performing a direction-specific trimming process to the spacer material and the second layer
Implementation Method 2
A direction-specific trimming process using neutral ion beam physical etching with a specific tilt angle is employed to enlarge the contact opening in the Y-direction while maintaining its size in the X-direction
Data Source
AI summary
The present disclosure discloses a method of fabricating a semiconductor device. A first layer is formed over a substrate. A patterned second layer is then formed over the first layer. The patterned second layer includes an opening. A spacer material is then deposited in the opening, thereby reducing the opening in a plurality of directions. A direction-specific trimming process is performed to the spacer material and the second layer. Thereafter, the first layer is patterned with the second layer.