Variable Space Mandrel Cuts in Multiple Patterning
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Solution Overview
Problem
Current semiconductor device fabrication techniques face challenges in achieving precise spacing between device features due to limitations in existing lithography methods, particularly in forming cuts or gaps in mandrel lines without damaging adjacent sidewall spacers.
Innovation Solution
A method involving the formation of mandrel lines and sidewall spacers on a patternable layer, where a portion of the mandrel line is removed to create a gap, and a gapfill material, composed of the same material as the sidewall spacers, is deposited to fill the gap, allowing for precise control of gap size independent of spacer dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional lithography methods are used to form mandrel lines, then device features can be patterned, but precise spacing control between features is limited
Solution Approach 1:
The mandrel line is segmented by introducing gaps that divide it into multiple sections. This segmentation allows independent control of spacing in different regions, enabling precise spacing control while maintaining the overall patterning function of the mandrel structure
Solution Approach 2:
A gapfill material is introduced as an intermediary substance to fill the gaps in the mandrel line. This intermediary material has different etch selectivity compared to the mandrel material, allowing it to serve as a mediator that protects underlying features during etching while enabling precise gap positioning
2Adaptability or versatility
If cuts are made in mandrel lines to create gaps, then spacing flexibility is improved, but adjacent sidewall spacers may be damaged
Solution Approach 1:
The gapfill material acts as an intermediary protective layer during the etching process. It fills the gaps and provides mechanical support and etch protection to adjacent sidewall spacers, preventing damage while allowing flexible gap positioning in the mandrel line
Solution Approach 2:
The gapfill material is deposited beforehand to cushion and protect the sidewall spacers from potential damage during subsequent etching operations. This prior protective measure ensures spacer integrity while enabling the mandrel line to be cut with flexible positioning
3Manufacturing precision
If gap size is determined by mandrel line or spacer dimensions, then manufacturing precision is maintained, but adaptability for different gap sizes is reduced
Solution Approach 1:
The gap size is controlled by changing the parameters of the gapfill material deposition process (such as deposition thickness, pattern dimensions) rather than being constrained by mandrel or spacer dimensions. This allows independent adjustment of gap size to meet different design requirements while maintaining manufacturing precision
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 enables the creation of precise gaps in mandrel lines, allowing for more flexible and accurate patterning in integrated circuit fabrication, with gap sizes determined by the patterned etch mask, not restricted by mandrel line or spacer dimensions, enhancing the capability for smaller feature sizes in integrated circuits.
Implementation Method 1
depositing a gapfill material in the gap in the first mandrel line
Data Source
AI summary
Methods of multiple patterning. First and second mandrel lines are formed on a patternable layer. Sidewall spacers are formed on the patternable layer adjacent to the first mandrel line and adjacent to the second mandrel line. A portion of the first mandrel line is removed to form a gap in the first mandrel line. A gapfill material is deposited in the gap in the first mandrel line. The gapfill material and sidewall spacers are composed of the same material.