Stacked Chip Optical Coupling With Protrusion-Groove Alignment
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Solution Overview
Problem
Existing technologies face challenges in efficiently integrating stacked photonic chips for applications in telecommunications, data communications, sensing, and quantum computing, as they often result in high optical signal loss and inefficient coupling between different types of chips or wafers.
Innovation Solution
A method of forming a structure by stacking chips with an optical waveguide protrusion positioned in a groove of the second chip, using laser ablation and lithography to precisely align and bond the chips, facilitating optical coupling with reduced loss through dielectric and metal-metal bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional stacking methods are used to integrate photonic chips, then chip integration is achieved, but optical signal loss increases and coupling efficiency decreases
Solution Approach 1:
The patent introduces an optical waveguide protrusion as an intermediary structure that extends from the first chip into the second chip, and a corresponding groove in the second chip to receive it. This intermediary waveguide structure mediates the optical coupling between the two chips, enabling efficient optical signal transmission while reducing optical signal loss compared to conventional direct stacking methods
Solution Approach 2:
The patent transitions from planar optical coupling to three-dimensional optical coupling by having the optical waveguide protrusion extend vertically from the first chip into the second chip. This dimensional change allows for more efficient optical field overlap and coupling between chips, improving optical signal transmission quality while reducing loss
2Adaptability or versatility
If chips are stacked to increase functionality, then device capabilities are enhanced, but alignment precision between chips becomes more difficult to achieve
Solution Approach 1:
The optical waveguide protrusion and groove structures are formed during the chip fabrication process before stacking. The protrusion is pre-formed on the first chip and the groove is pre-formed on the second chip, establishing predetermined alignment features that guide the stacking process and ensure precise alignment between chips, thereby maintaining manufacturing precision while enabling enhanced device functionality
Solution Approach 2:
The optical waveguide protrusion creates an asymmetric structural feature that provides unique alignment cues during stacking. This asymmetric geometry ensures that the chips can only be assembled in the correct orientation and position, automatically achieving precise alignment without requiring complex alignment mechanisms, thus maintaining manufacturing precision while enabling versatile device functionality
3Reliability
If optical waveguides are extended above dielectric layers to improve coupling, then optical coupling efficiency increases, but structural complexity increases
Solution Approach 1:
The optical waveguide protrusion serves multiple functions: it extends the optical waveguide path between chips for efficient optical coupling, provides a mechanical interlocking feature with the groove for structural stability, and acts as an alignment reference during assembly. By combining multiple functions into a single structure, the patent achieves improved optical coupling efficiency without proportionally increasing structural 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
The method enables efficient optical signal transmission between stacked chips with minimal loss, allowing for the creation of 3D device stacks with improved functionality and reduced optical coupling losses.
Implementation Method 1
using laser ablation and lithography to precisely align and bond the chips
Implementation Method 2
The optical waveguide protrusion extends above the first surface of the first chip. The structure further includes a second chip having a second surface adjacent to the first surface of the first chip
Data Source
AI summary
A structure includes a first chip having a first surface and a second chip having a second surface adjacent to the first surface of the first chip. The first chip includes a first optical component and an optical waveguide protrusion adjacent to the first optical component. The optical waveguide protrusion extends above the first surface of the first chip. The second chip includes a second optical component and a groove adjacent to the second optical component. The groove extends from the second surface of the second chip and into a portion of the second chip. The optical waveguide protrusion is positioned in the groove in the second chip.