Wire Grid Polarizer Fabrication Using Block Copolymer Alignment
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Solution Overview
Problem
Current methods for fabricating wire grid polarizers face challenges in reducing defective rates and achieving high yield, which affects their polarization efficiency and light reuse capabilities.
Innovation Solution
A method involving the formation of conductive wire patterns on a substrate using a block copolymer and guide patterns with specific etching techniques, including isotropic and anisotropic plasma etching, and heat or solvent annealing to align the block copolymer, ensuring the guide patterns have a trapezoidal or bottle shape with varying widths to prevent over-etching and improve alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional fabrication methods are used, then manufacturing simplicity is maintained, but defective rate increases and yield decreases
Solution Approach 1:
The fabrication process is segmented into multiple controlled stages: forming guide patterns with specific width variations, selective block copolymer alignment, and staged etching. This segmentation allows each step to be optimized independently, reducing cumulative defects and improving overall yield.
Solution Approach 2:
Guide patterns are formed in advance with predetermined width variations (narrower at top, wider at bottom) before block copolymer deposition. This preliminary structuring pre-defines the alignment zones and prevents over-etching, thereby reducing defects early in the process.
2Manufacturing precision
If guide patterns have uniform width, then fabrication is simpler, but over-etching occurs and alignment precision deteriorates
Solution Approach 1:
Guide patterns are designed with asymmetric width variation: the top width is narrower than the bottom width. This asymmetric geometry creates distinct alignment zones that improve block copolymer positioning precision while preventing over-etching, accepting increased structural complexity for gains in manufacturing precision.
Solution Approach 2:
Different sections of the guide pattern have different widths tailored to specific functions: the narrower top section provides precise alignment reference, while the wider bottom section prevents over-etching. This local differentiation optimizes each region's performance for its specific purpose.
3Manufacturing precision
If block copolymer alignment is not controlled, then process steps are reduced, but wire pattern precision deteriorates
Solution Approach 1:
The block copolymer alignment process utilizes parameter changes through heat treatment or solvent annealing to control the self-assembly and orientation of block copolymer domains. By adjusting temperature or solvent exposure, precise wire pattern formation is achieved without adding excessive process complexity.
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 results in a wire grid polarizer with high yield and improved polarization efficiency, allowing for efficient light reuse by reflecting and re-transmitting polarized light components, enhancing light efficiency and viewing angles.
Implementation Method 1
heat or solvent annealing to align the block copolymer
Implementation Method 2
isotropic and anisotropic plasma etching
Implementation Method 3
a parallel conductive wire array in which parallel conductive wires are arranged to polarize a specific polarized light component in an electromagnetic wave
Data Source
AI summary
A method for fabricating a wire grid polarizer according to an embodiment comprises: forming a conductive layer on a substrate; forming a guide layer on the conductive layer; forming a hard mask pattern to partially expose the guide layer; forming a guide pattern to partially expose the conductive layer; providing a block copolymer of two monomers having different etching rates; forming two sets of monomer blocks by aligning the block copolymer; selectively removing one set of monomer blocks; and forming a conductive wire pattern using the remaining set of monomer blocks and the guide pattern as etching masks. A width of an upper end of the guide pattern adjacent to the hard mask pattern is smaller than a width of a lower end adjacent to the conductive layer. The width of the upper end of the guide pattern is smaller than a width of the hard mask pattern.