Optical Package Focal Depth Control via Elastomeric Membrane Shaping
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Solution Overview
Problem
Conventional optical packages formed on a single wafer often exhibit inconsistent optical precision due to misalignments during fabrication, leading to varying focal depths among individual imagers, which can result in suboptimal performance in high-end digital systems.
Innovation Solution
The method involves forming an optical package with an elastomeric membrane over a material layer that can be adjusted using a shaping element to achieve precise focal depth, allowing for individual optimization of each imager's focal properties through exposure to curable conditions like UV radiation, ensuring consistent light capture and image clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple optical packages are formed simultaneously on a single wafer, then productivity is improved, but manufacturing precision deteriorates due to optical variation across the wafer
Solution Approach 1:
The patent divides the wafer into multiple regions, each containing imagers with similar optical characteristics. By segmenting the wafer map and assigning specific imager groups to different optical element fabrication regions, the system maintains high productivity while achieving consistent optical precision within each segment. This is accomplished through automated optical testing of individual imagers and mapping them to corresponding fabrication regions.
Solution Approach 2:
The patent changes physical parameters of the optical elements (such as curvature radius, thickness, or focal length) based on the specific optical characteristics of each imager. By adjusting these parameters according to measured optical properties, the system compensates for wafer-level variations and achieves consistent optical performance across all packages formed on a single wafer.
2Device complexity
If conventional optical elements are formed without individual adjustment, then device complexity is reduced, but measurement precision deteriorates due to inability to account for individual focal lengths
Solution Approach 1:
The patent performs preliminary optical testing and characterization of each imager before optical element fabrication. By measuring focal length, curvature, and other optical parameters in advance, the system prepares a detailed wafer map that guides subsequent optical element formation. This preliminary action enables precise focal depth control without significantly increasing overall device complexity.
Solution Approach 2:
The patent replaces manual or mechanical adjustment methods with automated optical testing and computer-controlled fabrication. Individual imager characterization uses automated optical benches and imaging systems, while optical element formation uses precision deposition and etching processes controlled by software based on the wafer map, achieving high measurement precision with manageable complexity.
3Manufacturing precision
If optical elements are tailored to each imager, then manufacturing precision is improved, but device complexity increases due to individualized fabrication requirements
Solution Approach 1:
The patent develops a universal fabrication approach that can handle individualized optical element requirements through standardized processes. A single wafer map generation system and automated testing platform serve multiple imagers with different optical characteristics, while the fabrication equipment uses programmable parameters to produce customized optical elements using the same base process flow, reducing complexity despite individualization.
Solution Approach 2:
The patent creates a digital copy or model of each imager's optical characteristics through automated testing and stores this information in a wafer map. This digital representation allows the fabrication system to replicate the required optical properties by adjusting process parameters based on the stored data, achieving precise customization without physical trial-and-error and thereby controlling 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 enables the fabrication of optical packages with tailored focal properties, enhancing light capture efficiency and image quality in digital systems by allowing for precise adjustment and curing of the material layer to match the specific requirements of each imager, thereby overcoming the inconsistencies in conventional methods.
Implementation Method 1
exposure of the material layer to curable conditions, such as, for example, ultraviolet (UV) radiation, thereby curing the material layer
Data Source
AI summary
Methods and apparatuses for forming optical packages, and intermediate structures resulting from the same are disclosed, which provide an optical element over a device. The optical element is formed by applying a force to lateral portions of a liquid material layer formed below an elastomeric material layer such that the liquid material layer has a radius of curvature sufficient to direct light to a light sensitive portion of the device, after which the liquid material layer is exposed to conditions which maintain the radius of curvature after the lateral force is removed.