Block Copolymer Self-Assembly for Nanostructure Patterning
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Solution Overview
Problem
The dual damascene process for semiconductor fabrication exposes metallic lines to harsh reactive ion etching, which can damage the interconnect structures and limit the precision of nanostructure formation in air bridge construction.
Innovation Solution
A method using a block copolymer film to pattern nano-columnar voids by segregating units on a heterogeneous reflectivity surface, applying radiation, and subsequent annealing and development steps to transfer the pattern into the underlying interlevel dielectric layer, allowing for precise nanostructure formation without direct exposure to reactive etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If reactive ion etching is used to transfer patterns into dielectric layers, then manufacturing precision can be achieved, but metallic lines are damaged and reliability deteriorates
Solution Approach 1:
The patent introduces a block copolymer self-assembly system as an intermediary patterning mechanism that operates independently of reactive ion etching. The copolymer forms nanoscale patterns through spontaneous phase separation, and these patterns are transferred to dielectric layers using non-damaging etch processes, thereby decoupling the patterning function from the damaging etch exposure
Solution Approach 2:
The block copolymer patterns are formed in advance before the dielectric layer patterning process. The self-assembled copolymer structures serve as pre-formed templates that guide subsequent etching operations, allowing the metallic lines to remain intact while still achieving precise pattern transfer into the dielectric layers
2Ease of manufacture
If conventional lithography is used to define via and line patterns, then manufacturing capability is maintained, but nanostructure precision is limited
Solution Approach 1:
The patent changes the fundamental parameter of pattern formation from top-down lithographic definition to bottom-up self-assembly. The block copolymer system naturally forms patterns at the nanoscale through thermodynamic phase separation, achieving dimensional precision (10-50 nm) that exceeds conventional lithography capabilities while maintaining compatibility with existing semiconductor manufacturing processes
Solution Approach 2:
The patent employs a composite material system consisting of block copolymers with distinct hydrophobic and hydrophilic blocks. This composite structure enables spontaneous phase separation into well-defined nanoscale domains, creating precise patterns that would be difficult to achieve with single-material lithographic approaches
3Reliability
If air bridge structures are constructed with traditional methods, then interconnect functionality is achieved, but void control precision is insufficient
Solution Approach 1:
The block copolymer system performs self-service patterning through autonomous self-assembly and phase separation. The copolymer chains spontaneously organize into periodic nanoscale structures without external patterning tools, and this self-generated pattern directly defines the void positions and sizes in the air bridge structures, achieving precision unattainable by conventional methods
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 the creation of precise nanostructures with controlled void sizes, enhancing the precision and reliability of air bridge construction in semiconductor fabrication while minimizing damage to metallic lines.
Implementation Method 1
forming a block copolymer film to pattern a heterogeneous surface; segregating the block copolymer into first units and second units
Implementation Method 2
applying radiation to the first units and second units, wherein the heterogeneous surface provides an exposed portion of the first units and the second units
Implementation Method 3
applying a first development step to at least the exposed portion of the first units and the second units, the first development step removing a portion of the exposed portion of the second units
Implementation Method 4
applying a first anneal to the block copolymer to segregate the block copolymer into the first and second units
Data Source
AI summary
In one embodiment, the present invention provides a method for patterning a surface that includes forming a block copolymer atop a heterogeneous reflectivity surface, wherein the block copolymer is segregated into first and second units; applying a radiation to the first units and second units, wherein the heterogeneous reflectivity surface produces an exposed portion of the first units and the second units; and applying a development cycle to selectively remove at least one of the exposed first and second units of the segregated copolymer film to provide a pattern.