3D Optical Material Stacking for Sub-Micron Patterning Without Planarization
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Solution Overview
Problem
Existing methods for creating 3D optical structures result in structures greater than a micron scale, which is undesirable for high-resolution applications like holograms, and face challenges in maintaining yield and controlling process budget due to material dissolution or destruction during subsequent layer processing.
Innovation Solution
A method for forming sub-micron 3D optical material structures involves depositing and patterning material stacks without planarization, using techniques such as etching, surface treatments, and alternating material pairs to create robust, customizable structures with reduced operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional multiple patterning methods are used to increase resolution, then manufacturing precision improves, but device complexity and process budget increase
Solution Approach 1:
The patent segments the patterning process into distinct etching and trimming stages. The etching process creates initial patterns at relaxed resolution, while subsequent trimming operations refine the patterns to achieve sub-micron precision. This segmentation allows resolution improvement without proportionally increasing overall process complexity.
Solution Approach 2:
The patent performs preliminary etching operations to create the basic pattern structure before applying trimming operations. By establishing the overall pattern geometry first, the subsequent trimming steps can focus solely on refining dimensions, thereby improving resolution without requiring complete repatterning.
2Manufacturing precision
If multiple material layers are deposited to create 3D structures, then manufacturing precision improves, but material dissolution or destruction occurs during subsequent processing
Solution Approach 1:
The patent changes the physical and chemical parameters of materials at different stages. Hard masks with specific etch resistance are used during etching operations, while soft masks are applied for trimming operations. This parameter change allows each material to withstand only the processing it requires, preventing dissolution or destruction during subsequent steps.
Solution Approach 2:
The patent introduces intermediary mask layers that protect underlying functional materials during processing. These masks act as mediators that absorb or resist the effects of subsequent processing steps, preventing direct interaction between processing chemicals and the functional material layers.
3Manufacturing precision
If planarization steps are included in the process, then manufacturing precision improves, but productivity decreases
Solution Approach 1:
The patent extracts and eliminates the planarization step from the conventional fabrication process. By designing the structure to be self-aligned and using trimming operations that work with the existing topography, the method achieves precision without requiring time-consuming planarization steps, thereby improving productivity.
4Manufacturing precision
If feature size is reduced to sub-micron scale, then manufacturing precision improves, but ease of manufacture deteriorates
Solution Approach 1:
The patent segments the pattern formation into etching and trimming phases. The etching phase creates patterns at a larger, easier-to-manufacture scale, while the trimming phase refines features to sub-micron dimensions. This segmentation makes the overall process easier to manufacture by avoiding the need to directly create sub-micron features in a single step.
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
Enables the construction of highly sophisticated, customizable 3D optical structures at a sub-micron scale with reduced operational steps, saving time and resources while maintaining structural integrity and resolution.
Implementation Method 1
trimming a side portion of the thick mask material; etching the material stack down one more level
Implementation Method 2
etching the material stack down one level
Data Source
Figure 1
Figure 2A~2F
Figure 3A~3F
AI summary
Embodiments herein describe a sub-micron 3D optical material structure and a method for forming the sub-micron 3D optical material structure. In a first embodiment, a method is provided for forming a sub-micron 3D optical material structure on a substrate without planarization. The method includes depositing a material stack to be patterned on a substrate, depositing and patterning a thick mask material on a portion of the material stack, etching the material stack down one level, trimming a side portion of the thick mask material, etching the material stack down one more level, repeating trim and etch steps above 'n' times, and stripping the thick mask material from the material stack.