Double Patterning Spacer Structures for Semiconductor Feature Precision
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Solution Overview
Problem
Conventional photolithography processes face limitations in forming small geometric features due to wavelength constraints, leading to inefficiencies in semiconductor device manufacturing, particularly in double patterning methods which are not entirely satisfactory.
Innovation Solution
A method involving the formation of mandrel masking structures, spacer layers, and sequential etching processes to create precise patterns in semiconductor devices, allowing for the transfer of target patterns into underlying layers with improved depth and critical dimension uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional photolithography processes are used, then the manufacturing process is simple, but the geometric size of features cannot be reduced below a certain limit due to wavelength constraints
Solution Approach 1:
The patent applies segmentation by dividing the single patterning process into multiple sequential steps: forming mandrels, depositing first spacers, depositing second spacers, and selective removal. This multi-stage double patterning approach enables feature sizes below the conventional photolithography limit by creating patterns in discrete stages rather than attempting to create all features in a single exposure step.
2Manufacturing precision
If double patterning methods are used to form small geometric features, then the feature size can be reduced, but the manufacturing process becomes more complex
Solution Approach 1:
The patent employs parameter changes by utilizing materials with different etch selectivities for the first and second spacer layers. The first spacer layer is designed to be selectively removable by a first etchant while the second spacer layer remains intact, and vice versa. This selective etching based on material parameter differences enables precise pattern transfer and improves manufacturing precision while managing process complexity through systematic material selection.
3Manufacturing precision
If spacers are formed on mandrel sidewalls and mandrels are removed, then precise patterns can be transferred, but damage may occur to hard mask structures
Solution Approach 1:
The patent introduces spacer layers as intermediary structures between the mandrels and the final pattern transfer. These spacers act as protective intermediaries that can be selectively deposited and removed without directly exposing the hard mask structures to harsh etching conditions. The spacers mediate the pattern transfer process, enabling precise feature definition while protecting underlying hard mask layers from damage.
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 enables precise and uniform pattern transfer, enhancing the manufacturing of semiconductor devices by mitigating damage to hard mask structures and adjusting opening widths through anisotropic etching, thereby improving feature uniformity and manufacturing efficiency.
Implementation Method 1
adjusting opening widths through anisotropic etching
Data Source
AI summary
A method for forming a semiconductor device structure is provided. The method includes forming a mandrel masking structure over a target layer. The method also includes patterning the mandrel masking structure to form mandrel lines parallel to each other, and forming spacer structures on sidewalls of the respective mandrel lines to define first openings. Each of the spacer structures includes a first spacer and a second spacer between the first spacer and the corresponding mandrel line. The method also includes removing the mandrel lines to define second openings, and etching the target layer through the first and second openings to form a target pattern therein.