Sidewall Spacer Patterning Using Gas Cluster Ion Beam
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Solution Overview
Problem
Conventional spacer etch processes in sidewall image transfer methods produce unacceptable results in terms of feature size reduction, sidewall footing, recess depth, and facet formation during the patterning of substrates, particularly in semiconductor manufacturing.
Innovation Solution
The use of gas cluster ion beam (GCIB) processing to partially remove a material layer on a substrate, allowing for precise control of the remaining material on sidewalls and selective removal of mandrel patterns, thereby achieving improved pattern doubling and pitch halving while minimizing unwanted etching effects such as excessive CD slimming, footing, and faceting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional spacer etch processes are used to transfer patterns, then the etching process can be performed, but unacceptable results occur including excessive sidewall slimming, footing, recess depth, and facet formation
Solution Approach 1:
The patent changes the etching process parameters by using gas cluster ion beam (GCIB) etching instead of conventional plasma etching. This involves changing the ion beam energy, gas composition, and etching conditions to achieve better sidewall profile control with minimal slimming, footing, and faceting while maintaining precise critical dimension control
Solution Approach 2:
The patent replaces the conventional plasma-based chemical etching mechanism with a gas cluster ion beam physical etching mechanism. This substitution allows for more precise control over material removal and sidewall profile formation, eliminating the harmful effects of footing and faceting that occur in conventional processes
2Manufacturing precision
If standard lithographic techniques are used for patterning, then the process is simple, but smaller feature sizes at smaller pitch cannot be achieved
Solution Approach 1:
The patent applies segmentation by dividing the patterning process into distinct stages: first forming mandrels with standard lithography, then using GCIB etching to create sidewall spacers, and finally removing the original mandrels to reveal the doubled pattern. This segmented approach enables feature size reduction while managing process complexity through systematic step breakdown
Solution Approach 2:
The patent uses sidewall spacers as an intermediary structure between the original mandrel pattern and the final doubled pattern. The spacers serve as a mediating element that allows pattern multiplication without requiring direct re-patterning, thus achieving feature size reduction while controlling process complexity
3Manufacturing precision
If GCIB processing is used to partially remove material layer, then precise control of remaining material on sidewalls is achieved, but additional process steps are required
Solution Approach 1:
The patent applies preliminary action by using GCIB etching to pre-form the sidewall spacers with precise material distribution before the final mandrel removal step. This preliminary shaping of the sidewall material ensures optimal pattern transfer and spacer formation, improving manufacturing precision while the added process step is justified by the significant gain in pattern quality
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
GCIB processing results in reduced CD reduction, minimized footing and recessing, and controlled faceting, leading to more precise and effective sidewall spacer patterning with improved performance metrics compared to traditional dry plasma etching techniques.
Implementation Method 1
partially removing the first material layer using a first gas cluster ion beam (GCIB) etching process
Implementation Method 2
gas cluster ion beam (GCIB) etching process
Data Source
AI summary
A method for patterning a substrate is described. The method includes receiving a substrate having a patterned layer, wherein the patterned layer defines a first mandrel pattern, and wherein a first material layer of a first composition is conformally deposited over the first mandrel pattern. The method further includes partially removing the first material layer using a first gas cluster ion beam (GCIB) etching process to expose a top surface of the first mandrel pattern, open a portion of the first material layer at a bottom region adjacent a feature of the first mandrel pattern, and retain a remaining portion of the first material layer on sidewalls of the first mandrel pattern; and selectively removing the first mandrel pattern using one or more etching processes to leave a second mandrel pattern comprising the remaining portion of the first material layer that remained on the sidewalls of the first mandrel pattern.