Block Copolymer Self-Assembly for Sub-20nm LWR Reduction
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Solution Overview
Problem
Current photolithographic techniques face challenges in controlling line width roughness (LWR) and line edge roughness (LER) for sub-20 nm technologies, which affect transistor performance and circuit stability, with existing methods like plasma treatment introducing additional steps and not achieving sufficient reduction in LWR/LER values.
Innovation Solution
A method involving a photo resist layer on a composite substrate, where a block copolymer with two components is used to form a lamellar structure, followed by sequential infiltration synthesis (SIS) and self-aligned multiple patterning (SAMP) processes to reduce LWR/LER, utilizing the block copolymer's phase separation and selective infiltration to create a metallic mandrel structure for pattern transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithographic techniques are used for pattern formation, then manufacturing capability is achieved, but line width roughness and line edge roughness increase affecting device performance
Solution Approach 1:
A block copolymer layer is introduced as an intermediary between the photo resist pattern and the final pattern transfer. The block copolymer self-assembles into lamellar structures that act as a mediating template, enabling the formation of smoother, more precise patterns while decoupling the limitations of photolithography from the final pattern quality.
Solution Approach 2:
The invention changes the physical and chemical parameters of the patterning process by transitioning from direct photo resist patterning to a two-stage process involving block copolymer self-assembly. This includes changing the temperature conditions during annealing to induce phase separation and control the morphology of the block copolymer structures.
2Manufacturing precision
If plasma treatment is applied to reduce LWR/LER, then line smoothness improves, but process complexity increases due to additional plasma steps
Solution Approach 1:
The block copolymer layer performs self-service by automatically self-assembling into ordered lamellar structures through phase separation during annealing. This self-organizing behavior eliminates the need for additional plasma treatment steps, as the block copolymer inherently provides the smoothing function that would otherwise require complex plasma processing.
3Length of moving object
If feature dimensions are reduced for sub-20 nm technologies, then transistor scaling is achieved, but line width roughness impact on performance increases
Solution Approach 1:
The patterning process is segmented into distinct stages: photo resist patterning, block copolymer deposition, thermal annealing for phase separation, and pattern transfer. This segmentation allows each stage to be optimized independently, with the block copolymer stage specifically addressing the line width roughness issue at sub-20 nm dimensions.
Solution Approach 2:
The invention adds a vertical dimension to the patterning process by introducing a block copolymer layer above the photo resist pattern. This additional layer provides a new degree of freedom for controlling pattern morphology, allowing the formation of smoother lateral features through vertical self-assembly and phase separation.
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 effectively reduces LWR and LER to values smaller than 2 nm and 3 nm, respectively, enhancing the precision of patterned structures and improving device performance by minimizing variance in feature dimensions.
Implementation Method 1
subjecting the block copolymer to predetermined conditions as to cause phase separation of the first component and the second component along the composite substrate
Implementation Method 2
performing a sequential infiltration synthesis (SIS) process on the mandrel structure of the first component (e.g. hereby synthesizing a metallic compound selectively in the mandrel structure of the first component)
Data Source
AI summary
The present disclosure relates to a method for pattern formation on a substrate. An example embodiment includes a method for pattern formation. The method includes providing a photoresist layer on a composite substrate. The method also includes patterning the photoresist layer by lithography to define a plurality of parallel stripe photoresist structures. The method further includes providing a block copolymer on and along the composite substrate, in between the parallel stripe photoresist structures. The block copolymer includes a first component and a second component. The method additionally includes subjecting the block copolymer to predetermined conditions to cause phase separation of the first component and the second component. In addition, the method includes performing a sequential infiltration synthesis process. Still further, the method includes selectively removing the parallel stripe photoresist structures. Additionally, the method includes defining a core stripe structure. Even further, the method includes performing a self-aligned multiple patterning process.