Semiconductor Contact Hole Spacer Etching for Alignment Margin
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Solution Overview
Problem
As semiconductor devices become increasingly high-density and smaller, they are prone to defects and performance degradation due to slight misalignment or process variations during deposition and etching processes, which can lead to reliability issues and conduction defects.
Innovation Solution
The method involves forming a semiconductor device with a structure that includes a first and second line pattern, spacer structures, and conductors, where an expanded opening is created by etching the spacer structures, allowing for a wider conductive pattern and increased process margin, using a wet etching process with specific pH and etch selectivity to ensure reliable insulation and prevent short-circuit failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If semiconductor device elements are made smaller for high density integration, then device density increases, but manufacturing precision and reliability deteriorate due to slight misalignment or process variation
Solution Approach 1:
The patent applies preliminary action by forming an expanded opening in the spacer structure before filling it with conductor material. This pre-expansion creates a larger tolerance zone that compensates for potential misalignment in subsequent deposition and etching processes, allowing the conductor to be reliably formed even with process variations.
Solution Approach 2:
The patent changes the geometric parameters of the contact structure by creating an expanded opening with width greater than the lower part opening. This parameter change from a uniform to a tapered geometry provides a larger process margin, enabling reliable conductor formation despite variations in deposition thickness or etching depth.
2Ease of manufacture
If conventional contact hole structures are used, then manufacturing process is simple, but reliability deteriorates due to insufficient process margin against misalignment
Solution Approach 1:
The patent segments the contact structure into distinct regions: a lower part opening and an expanded opening. This segmentation allows the structure to provide both mechanical support from the narrower base and alignment tolerance from the wider upper portion, improving reliability without significantly complicating the manufacturing process.
Solution Approach 2:
The patent introduces a dimensional change by creating an expanded opening that is wider at the upper portion than at the lower part. This vertical dimensionality change in the opening geometry provides additional process margin in the horizontal plane, enabling reliable conductor formation even with misalignment.
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 enhances the reliability of semiconductor devices by providing a sufficient process margin and preventing short-circuit failures, ensuring stable performance even with minor misalignment or process variations.
Implementation Method 1
Etching the upper portions of the first and second spacer structures may include performing a wet etching process using an etchant having a pH of about 3 or less and an etch selectivity of an oxide film to a nitride film of 10:1 or less.
Data Source
AI summary
Semiconductor devices and methods of forming the same are provided. The methods may include forming first and second line patterns. The first line pattern has a first side facing the second line pattern, and the second line pattern has a second side facing the first line pattern. The methods may also include forming a first spacer structure on the first side of the first line pattern and a second spacer structure on the second side of the second line pattern. The first and the second spacer structures may define an opening. The methods may further include forming a first conductor in a lower part of the opening, forming an expanded opening by etching upper portions of the first and second spacer structures, and forming a second conductor in the expanded opening. The expanded opening may have a width greater than a width of the lower part of the opening.