Optical Chip Rear Hollowing With Planar Oxide Support
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Solution Overview
Problem
Existing optical chip technologies face issues with mechanical strength and stability due to fragile silicon oxide suspension beams, limited flexibility in metal routing and waveguide design, and interference from adhesive filling in advanced packaging processes, particularly in high-density applications.
Innovation Solution
The optical chip design includes a rear substrate hollowed structure with a planar support formed by stacked oxide layers, eliminating the need for front-side etching and allowing for flexible waveguide and metal routing, while enabling superimposition with semiconductor processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If front substrate hollowing with silicon oxide suspension beam is used, then substrate hollowing is achieved, but mechanical strength and stability deteriorate
Solution Approach 1:
The patent inverts the traditional front-side hollowing approach by performing substrate hollowing from the rear side. This allows the front surface to maintain its structural integrity while achieving the desired hollowed structure, thereby resolving the contradiction between substrate hollowing and mechanical strength.
Solution Approach 2:
The patent employs composite material structures with multiple layers including silicon oxide layers, silicon nitride layers, and metal layers. These composite structures provide both the necessary hollowing functionality and enhanced mechanical strength through the combined properties of different materials.
2Manufacturing precision
If etched window is used for substrate hollowing, then hollowing is completed, but flexibility of metal routing and waveguide design is limited
Solution Approach 1:
By inverting the hollowing process to the rear side, the patent eliminates the need for front-side etched windows, thereby restoring full flexibility to metal routing and waveguide design on the front surface without compromising substrate hollowing.
Solution Approach 2:
The patent moves the hollowing operation to another dimension (rear side) rather than constraining it to the front surface, allowing unrestricted design freedom on the front surface for metal routing and waveguide configurations.
3Manufacturing precision
If etched window is formed, then substrate hollowing is achieved, but process compatibility deteriorates due to adhesive filling interference
Solution Approach 1:
The patent resolves the process compatibility issue by performing hollowing on the rear side, which eliminates interference with adhesive filling processes on the front surface, thereby enabling better integration with advanced packaging processes.
Data Source
AI summary
The optical chip includes a substrate, a first oxide layer, a front functional structure layer, and a second oxide layer. The front functional structure layer covers a first region on a first surface of the first oxide layer. The second oxide layer covers the front functional structure layer and a region other than the first region. A rear substrate hollowed structure is disposed on the substrate of the optical chip. An inner surface of the substrate hollowed structure extends to a second region of the substrate. The second region includes a region that is opposite to the front functional structure layer, and a process window of the substrate hollowed structure is formed on a second surface of the substrate. A process window structure for hollowing the substrate is disposed on a rear side of the optical chip, the second oxide layer and the first oxide layer collectively form planar support.