Alignment Marks in Planar Lightwave Circuits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The alignment of cores in planar lightwave circuits is challenging due to the degradation of light signals caused by improper alignment, which is exacerbated by the presence of multiple layers with similar refractive indices, leading to blurred or obscured alignment marks and reduced accuracy.
Innovation Solution
The method involves forming a base layer over a substrate, followed by an alignment mark and subsequent layers with carefully controlled refractive indices, allowing for accurate alignment of components by ensuring the alignment mark is visible and clearly imaged through the layers, with the first and second layers having refractive indices within 0.05 units of each other.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alignment marks are positioned under multiple layers with similar refractive indices, then the structural integrity and optical function of the waveguide are maintained, but the alignment mark image becomes blurred and obscured, reducing alignment accuracy
Solution Approach 1:
The patent introduces a layer with a distinct refractive index (either higher or lower than surrounding layers) as an intermediary between the alignment mark and the observation plane. This intermediary layer enhances the optical contrast of the alignment mark, making it clearly visible through the multi-layer structure without compromising the structural integrity or optical function of the waveguide components.
2Illumination intensity
If multiple layers with slightly different refractive indices are used to form waveguide cores, then light transmission intensity is increased, but the perceived location of alignment marks shifts, making accurate alignment more difficult
Solution Approach 1:
The patent introduces a layer with a distinct refractive index (either higher or lower than surrounding layers) as an intermediary between the alignment mark and the observation plane. This intermediary layer enhances the optical contrast of the alignment mark, making it clearly visible through the multi-layer structure without compromising the structural integrity or optical function of the waveguide components.
3Device complexity
If the distance between the surface of the uppermost layer and the alignment mark is increased, then more layers can be incorporated into the waveguide structure, but the image of the alignment mark decreases in clarity and accuracy
Solution Approach 1:
The patent introduces a layer with a distinct refractive index (either higher or lower than surrounding layers) as an intermediary between the alignment mark and the observation plane. This intermediary layer enhances the optical contrast of the alignment mark, making it clearly visible through the multi-layer structure without compromising the structural integrity or optical function of the waveguide components.
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 precise alignment of components in integrated circuits, improving the clarity and accuracy of alignment marks, thereby enhancing the performance of planar lightwave circuits by maintaining the intensity and clarity of light signals.
Implementation Method 1
The first and second layers have a first and second refractive index, respectively, that are within about 0.05 units of each other
Data Source
AI summary
Methods of producing integrated circuits with interposers and integrated circuits produced from such methods are provided. In an exemplary embodiment, a method of producing an integrated circuit includes forming a base layer overlying a substrate, and forming an alignment mark overlying the base layer. A first layer is formed overlying the base layer and the alignment mark, and the first layer has a first layer thickness. A second layer is formed overlying the first layer, where the second layer has a second layer thickness and where a combined thickness of the first and second layer thicknesses is from about 2 to about 50 micrometers. A second component is formed from the second layer.