Optical Package Structure With Trench-Aligned Short Optical Path
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Solution Overview
Problem
The integration density of electronic components in semiconductor packaging is increasing, leading to challenges in 3DICs, such as longer optical paths for signal transmission, which affect the speed and efficiency of optical signals.
Innovation Solution
The proposed solution involves an optical package structure that includes a photonic integrated circuit die, an electronic integrated circuit die, an oxide layer, and a silicon carrier with a trench formed directly over the coupler, allowing for a shorter optical path and improved alignment accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple semiconductor dies are stacked upon one another in 3DIC packaging, then integration density is improved, but interconnect length increases leading to slower signal transmission
Solution Approach 1:
The patent transitions from planar 2D packaging to three-dimensional stacked packaging, arranging multiple semiconductor dies vertically in the Z-dimension. This dimensional change enables higher integration density while the interposer and through-silicon vias provide direct vertical interconnection paths, minimizing interconnect length and maintaining high signal transmission speed despite the increased number of dies.
2Ease of manufacture
If conventional packaging structures are used, then manufacturing is simpler, but optical path length is longer affecting optical signal efficiency
Solution Approach 1:
The patent extracts the optical coupling function from the conventional packaging structure by introducing a dedicated optical interposer with waveguide structures. This separate optical pathway is extracted from the electrical interconnect structure, allowing for a direct and short optical path between laser diodes and photodetectors while maintaining the benefits of 3D stacked packaging for electrical components.
Solution Approach 2:
The patent introduces an optical interposer as an intermediary component between the laser diode die and photodetector die. This intermediary contains waveguide structures that provide a dedicated optical transmission path, shortening the optical path length and improving optical signal efficiency while allowing the electrical packaging structure to remain relatively conventional.
3Ease of manufacture
If standard alignment procedures are used in 3DIC packaging, then manufacturing process is straightforward, but alignment accuracy is insufficient for precise optical coupling
Solution Approach 1:
The patent implements preliminary alignment actions by forming alignment marks and guide structures during the wafer-level processing stage, before the actual die stacking. The optical interposer includes pre-formed waveguide structures and alignment features that guide the positioning of laser diode and photodetector dies, ensuring high alignment accuracy for optical coupling while maintaining a straightforward manufacturing process through automated wafer-level operations.
Data Source
AI summary
An optical package structure is provided. The optical package structure includes a photonic integrated circuit die, an electronic integrated circuit die, an oxide layer, and a silicon carrier. The photonic integrated circuit die includes a coupler. The electronic integrated circuit die is bonded to the photonic integrated circuit die. The oxide layer is adjacent to the electronic integrated circuit die. The silicon carrier includes a first part over the electronic integrated circuit die and a second part over the oxide layer. A trench is formed in the second part of the silicon carrier.