Apertures for Flat Optical Devices Stray Light Control
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Solution Overview
Problem
The fabrication of optical devices with transparent substrates is complex due to issues with stray light from beams larger than the device, which degrades the functionality and efficiency of optical systems.
Innovation Solution
A method involving the disposition of an aperture material layer on a substrate, patterning to form apertures surrounding optical devices, and subsequent deposition of a structure material layer with a hardmask and photoresist to create nanostructures, preventing stray light from interfering with the optical devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If beams are used to illuminate or process the optical devices, then the optical devices can be activated and function, but stray light from beams larger than the device degrades the functionality and efficiency of the optical system
Solution Approach 1:
The patent extracts and removes the harmful stray light components by introducing aperture structures that selectively block light outside the desired optical paths. The apertures are positioned to eliminate stray light while preserving the useful beam energy, thereby separating the harmful light components from the useful ones.
Solution Approach 2:
The aperture structures serve as intermediary elements between the light source and the optical devices. These apertures mediate the light transmission by allowing only the desired light paths to pass through while blocking stray light, thus protecting the optical devices from harmful light interference.
2Illumination intensity
If transparent substrates are used for optical devices, then light transmission is enabled, but processing complexity increases due to the need to form structures on the substrate
Solution Approach 1:
The fabrication process is segmented into distinct sequential steps: forming the aperture material layer first, then depositing the structure material layer, followed by patterning and etching. This segmentation allows each step to be optimized independently and simplifies the overall manufacturing process by breaking down the complex fabrication into manageable stages.
Solution Approach 2:
The aperture material layer is deposited and patterned before the structure material layer is formed. This preliminary action establishes the light-blocking regions in advance, which then guide the subsequent structure formation process. The pre-formed aperture pattern serves as a template that simplifies the later structuring steps.
3Reliability
If apertures are formed surrounding each optical device, then stray light is blocked and optical efficiency is improved, but the fabrication process becomes more complex
Solution Approach 1:
The aperture formation and structure material deposition processes are merged into a unified fabrication sequence. The aperture material layer and structure material layer are deposited in sequence, and both are patterned using the same photolithography and etching steps. This merging reduces the total number of separate process modules required and streamlines the overall fabrication workflow.
Data Source
AI summary
Embodiments described herein relate to methods for fabricating optical devices. The methods described herein enable the fabrication of one or more optical devices on a substrate with apertures surrounding each of the optical devices having a plurality of structures. One embodiment of the methods described herein includes disposing an aperture material layer on a surface of a substrate, disposing a structure material layer over the apertures and the surface of the substrate, disposing a hardmask over the apertures and the structure material layer, disposing a patterned photoresist over the hardmask, the patterned photoresist defining exposed hardmask portions, removing the exposed hardmask portions to expose structure portions of the structure material layer, and removing the structure portions to form a plurality of structures between the apertures over regions of the surface of the substrate.