Stepped Substrate Cavities for Deep Optical Component Integration
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Solution Overview
Problem
Legacy semiconductor packaging techniques face challenges in creating deep cavities with sloping edges, leading to increased power efficiency losses, longer power supply routes, and difficulties in fiber attachment due to stencil keep-out zones and sloping edges, which hinder the integration of optical components like PICs and lenses within substrates.
Innovation Solution
A substrate cavity formation process using CO2 laser drilling and etching techniques to create stepped walls, allowing for deeper cavities that accommodate optical components, such as PICs and lenses, by splitting the cavity depth into multiple shallow layers with copper stop pads to maintain precise alignment and reduce power efficiency losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If deep cavities are formed using legacy drilling techniques, then cavity depth is increased, but power efficiency losses increase and power supply routes become longer
Solution Approach 1:
The cavity formation process is segmented into multiple drilling stages, with copper stop pads placed at intermediate depths to create stepped walls. This segmentation allows power supply routes to be optimized at each level rather than extending the full cavity depth, reducing power efficiency losses while achieving the required cavity depth.
2Length of stationary object
If deep cavities are formed with sloping edges, then cavity depth is increased, but fiber attachment becomes difficult due to stencil keep-out zones
Solution Approach 1:
The cavity is divided into multiple shallow layers with horizontal stepped walls created by intermediate copper stop pads. This segmentation eliminates sloping edges that create stencil keep-out zones, providing flat surfaces at each level that facilitate easy fiber attachment and alignment while still achieving the required total cavity depth.
3Device complexity
If single-stage deep cavity drilling is performed, then manufacturing process is simplified, but manufacturing precision decreases due to sloping edges and alignment difficulties
Solution Approach 1:
The manufacturing process is divided into multiple drilling stages with copper stop pads at intermediate levels. Each stage creates a shallow cavity with a flat horizontal wall, ensuring precise alignment. The stepped structure with vertical transitions between levels maintains manufacturing precision while achieving deep cavity formation.
Solution Approach 2:
Copper stop pads are placed at predetermined intermediate positions before the final drilling stage. These preliminary structures guide the drilling process and ensure precise positioning of the stepped cavity walls, maintaining high manufacturing precision throughout the multi-stage process.
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 process enables efficient integration of optical components within substrates by reducing power efficiency losses and facilitating direct connections, while allowing for precise fiber attachment and alignment, thereby enhancing the integration of high-density photonic devices.
Implementation Method 1
A substrate cavity formation process using CO2 laser drilling and etching techniques to create stepped walls
Data Source
AI summary
Embodiments described herein may be related to apparatuses, processes, and techniques related to creating deep cavities within a substrate or at an edge of the substrate, by etching a cavity in the substrate to a first copper stop layer, removing the first copper stop layer, and then etching deeper into the cavity to a second copper stop layer. In embodiments this process may be repeated until the desired cavity depth is reached. Other embodiments may be described and/or claimed.