Aligned Photonic Dies Using Etch Stops for Low-Loss Coupling
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Solution Overview
Problem
Existing photonic integrated circuits face challenges in aligning multiple photonic dies with precise alignment to minimize optical losses during light transmission.
Innovation Solution
Utilizing etch stop layers to define vertical alignment between photonic dies, with layers like silicon dioxide acting as etch stops to control etching processes and create precise mechanical structures for alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple photonic dies are integrated to add functional components, then the functionality and versatility of the photonic integrated circuit are improved, but the alignment precision between dies deteriorates, leading to increased optical losses
Solution Approach 1:
The patent introduces alignment posts as intermediary structures that mediate between different photonic dies. These posts serve as physical reference points that enable precise alignment when multiple dies are stacked, thereby maintaining manufacturing precision while allowing integration of multiple functional components with different material systems
Solution Approach 2:
The alignment posts are formed in the lower photonic die before stacking the upper die. This preliminary action establishes the alignment reference structure in advance, ensuring that when the dies are assembled, the alignment precision is already predetermined by the post positions, thus resolving the alignment precision issue while maintaining versatility
2Manufacturing precision
If alignment structures are added to improve alignment precision, then the manufacturing precision is improved, but the device complexity increases
Solution Approach 1:
The alignment posts serve multiple functions: they provide mechanical support between dies, establish vertical alignment references, and enable precise positioning of optical components. By making the posts multi-functional, the patent improves alignment precision without proportionally increasing device complexity, as the same structure accomplishes multiple objectives
3Manufacturing precision
If etching processes are controlled to create precise alignment structures, then the manufacturing precision is improved, but the production time and complexity increase
Solution Approach 1:
The patent segments the etching process into multiple selective steps, each targeting specific material layers with different etch rates. By dividing the overall etching process into manageable segments that can be independently controlled and optimized, precise alignment structures are achieved while maintaining reasonable production efficiency through systematic process organization
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
Achieves precise vertical alignment and reduced optical losses by controlling etching processes, allowing for efficient light coupling and electrical connections between photonic dies.
Implementation Method 1
a first etch stop layer defining a position of a post within the first photonic die
Data Source
AI summary
Various embodiments disclosed herein describe photonic integrated circuits having multiple photonic dies, and techniques for vertically aligning two photonic dies of a photonic integrated circuit. In some variations, a photonic die may include a cladding layer that is used to define a bottom surface of a waveguide layer. A portion of the cladding layer is used as an etch stop to define a top surface of a post, which may assist in vertically aligning the photonic die relative to an additional photonic die. Additionally or alternatively, a photonic die may include a ridge waveguide and multiple etch stop layers, of which a first etch stop layer defines a height of the ridge waveguide and a second etch stop layer defines a contact surface. The contact surface may contact a portion of an additional photonic die to help provide vertical alignment between the two photonic dies.