O-SIP Optical Module Layout Without Conductive Vias
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Solution Overview
Problem
The existing conductive via method in semiconductor packaging for optical/electric packages increases material and process costs, limits terminal pad arrangement to fan-out only, and hinders heat dissipation due to the perpendicular optical paths and separate locations of RDL and terminal pads.
Innovation Solution
An optical system-in-package (O-SIP) that integrates photonic and electronic ICs within a mold body, eliminating the need for conductive vias by using a fan-out wafer level package (FOWLP) technology, which allows for both fan-in and fan-out terminal pad arrangements and improved heat dissipation through metal structures and redistribution layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive via is used to connect terminal pads on the opposite surface of the package, then electrical connection is achieved, but material cost and process cost increase
Solution Approach 1:
The patent removes the conductive via structure from the package design. Instead of forming vias through the package substrate to connect opposite surfaces, the terminal pads are arranged on the same surface (first surface) where the optical path is located, eliminating the need for through-package via holes and their associated high-cost materials and processes.
Solution Approach 2:
The patent changes the spatial arrangement of terminal pads from a three-dimensional configuration (across opposite surfaces requiring vertical via connections) to a two-dimensional configuration (all on the first surface). This dimensional reorganization eliminates the need for depth-directional electrical connections through the package, thereby removing the requirement for conductive vias.
2Ease of manufacture
If terminal pads are arranged only in fan-out form due to conductive via structure, then manufacturing is simplified, but integration advantage is lost and package area increases
Solution Approach 1:
The patent enables terminal pads to be arranged in both fan-in and fan-out configurations by placing them all on the first surface of the package. This two-dimensional arrangement on a single surface allows flexible routing patterns that can converge (fan-in) or diverge (fan-out) without requiring vertical via connections, thus achieving high integration density while maintaining manufacturing simplicity.
3Adaptability or versatility
If RDLs are formed on both sides of the package to enable fan-in and fan-out pads, then terminal pad arrangement flexibility is improved, but process cost increases and heat transfer path is hindered
Solution Approach 1:
The patent eliminates the need for dual-sided RDL formation by concentrating all terminal pads on the first surface. This removes the requirement for complex alignment and bonding processes on both sides of the package, significantly reducing process cost. Additionally, the single-sided configuration preserves the heat transfer path from the optical path region through the package substrate to the heat dissipation structure on the second surface, avoiding thermal interference from additional RDL layers.
Data Source
AI summary
Provided are an optical module and an optical transceiver using an optical system-in-package (O-SIP) including a photonic integrated circuit (IC), an electronic IC, and the like, in a package. The optical module includes: an optical system-in-package (O-SIP) for generating an optical signal or receiving an optical signal, in which a photonic integrated circuit (IC) and an electronic IC for driving or interfacing the photonic IC are molded inside a mold body having a first surface and a second surface which are flat, on a lower portion and an upper portion of the mold body, respectively; and a vertical coupler mounted on an upper portion of the O-SIP and having a through hole corresponding to a light entrance/exit part of the photonic IC inside the mold body, wherein an optical fiber is coupled to the through hole.