Directed Self-Assembly Using Restricted Mandrel Patterns for Rectangular Arrays
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Solution Overview
Problem
Current directed self-assembly (DSA) processes in semiconductor manufacturing struggle to create cylindrical nanodomains in rectangular or square arrays, which are necessary for advanced semiconductor device design, as they typically form hexagonal arrays that do not align with existing IC design and fabrication requirements.
Innovation Solution
The method involves forming mandrel patterns with restricted sizes and configurations, such as checkerboard-like arrangements, to guide the self-assembly of block copolymers, resulting in cylindrical nanodomains arranged in rectangular or square arrays by using spacers on the sidewalls of the mandrel patterns, which are then used to induce microphase separation and form desired patterns on the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional DSA processes use guide patterns to direct self-assembly, then nanoscale features can be formed, but the self-assembled polymer features form hexagonal arrays instead of the desired rectangular or square arrays
Solution Approach 1:
The patent introduces spacers as intermediary structures formed on the sidewalls of mandrel patterns. These spacers act as a mediating element that translates the mandrel pattern geometry into the desired rectangular or square nanodomain arrays during DSA. The spacers provide the necessary geometric constraints to guide block copolymer self-assembly into non-hexagonal configurations, resolving the contradiction between achieving precise pattern control and obtaining IC-compatible rectangular arrays.
Solution Approach 2:
The patent segments the guiding structure into multiple components: mandrel patterns and spacers. This segmentation allows independent optimization of each component's function - mandrels provide the base pattern geometry while spacers add the necessary sidewall constraints. By dividing the guiding function across multiple structural elements, the process achieves both precise pattern control and rectangular array formation compatibility.
2Productivity
If optical lithography is used for patterning, then existing IC manufacturing processes can be maintained, but technological and economical limits are approached that prevent further scaling
Solution Approach 1:
The patent employs directed self-assembly where block copolymers automatically organize into ordered nanoscale structures through their inherent self-assembling properties. This self-service mechanism eliminates the need for further lithographic scaling, allowing the process to maintain production efficiency while achieving sub-lithographic feature sizes. The self-assembly process naturally produces the desired patterns without requiring additional manufacturing steps.
Solution Approach 2:
The patent changes the fundamental parameter of pattern formation from top-down lithographic writing to bottom-up self-assembly. By transitioning to a different physical mechanism (block copolymer microphase separation), the process bypasses optical lithography limits while maintaining compatibility with existing manufacturing workflows. The guide patterns and spacers control the self-assembly parameters to produce the required rectangular or square nanodomain arrays.
3Ease of manufacture
If hexagonal arrays are formed by DSA, then self-assembly occurs naturally, but the patterns do not align with existing IC design and fabrication requirements
Solution Approach 1:
The spacers serve as an intermediary that bridges the natural hexagonal self-assembly tendency and the desired rectangular array configuration. By providing geometric constraints through the spacer structures, the process maintains the simplicity of self-assembly while achieving IC-design-compatible rectangular patterns. This intermediary approach preserves ease of manufacture through self-assembly while ensuring design flow compatibility.
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 effectively produces nanodomains that conform to existing IC design and fabrication flows, enabling the creation of densely packed, uniformly sized contact holes suitable for semiconductor devices, improving manufacturing efficiency and compatibility.
Implementation Method 1
inducing microphase separation within the copolymer material, thereby defining a first constituent polymer surrounded by a second constituent polymer
Implementation Method 2
depositing a copolymer material in the trenches, wherein the copolymer material is directed self-assembling
Data Source
AI summary
A method includes providing a substrate; forming mandrel patterns over the substrate; and forming spacers on sidewalls of the mandrel patterns. The method further includes removing the mandrel patterns, thereby forming trenches that are at least partially surrounded by the spacers. The method further includes depositing a copolymer material in the trenches, wherein the copolymer material is directed self-assembling; and inducing microphase separation within the copolymer material, thereby defining a first constituent polymer surrounded by a second constituent polymer. The mandrel patterns have restricted sizes and a restricted configuration. The first constituent polymer includes cylinders arranged in a rectangular or square array.