Photonic Integrated Circuit Package With Flip-Chip Engagement
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Solution Overview
Problem
Existing package structures for photonic integrated circuits face issues with radio frequency performance degradation due to bonding wire length variability, increased cost from optical fiber requirements, and difficulty in reworking due to precise positioning of chips and optical modules, along with electrical signal interference like crosstalk.
Innovation Solution
The package structure employs flip-chip engagement of chips to a substrate with optical modules positioned in recessed portions, eliminating the need for bonding wires and reducing electrical signal overlap, thereby enhancing tolerance to positional errors and allowing easier reworking without carriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonding is used to engage chip and optical module with circuit board, then electrical connection is achieved, but radio frequency performance deteriorates due to bonding wire length variability
Solution Approach 1:
The patent removes the bonding wire from the connection system by using flip-chip engagement. The chip is directly engaged with the substrate through bump balls, eliminating the bonding wire that causes RF performance degradation. This extraction of the problematic element (bonding wire) directly resolves the contradiction between achieving electrical connection and maintaining RF performance.
Solution Approach 2:
The patent replaces the mechanical wire bonding system with a direct flip-chip engagement system. Instead of using flexible bonding wires to connect circuits, the chip is directly mounted and engaged with the substrate through bump balls, substituting the mechanical wire-based connection with a rigid direct connection that eliminates RF interference from wire length variations.
2Reliability
If optical fibers are provided for optical paths, then optical signal transmission is achieved, but cost increases
Solution Approach 1:
The patent merges the optical module with the chip structure by positioning the optical module within the chip's recessed portion. This integration eliminates the need for separate optical fibers to connect the chip and optical module, as the optical path is established through the integrated structure. The consolidation of multiple components into a unified structure reduces component count and manufacturing cost while maintaining optical signal transmission functionality.
3Stability of the object's composition
If chip and optical module are adhered to carrier and fixed, then stable mounting is achieved, but reworking becomes difficult
Solution Approach 1:
The patent introduces a reversible engagement mechanism through the flip-chip structure with bump balls. The chip is engaged with the substrate through these bump balls that can be selectively removed or repositioned, providing dynamic adjustability. This allows the mounting to be stable during operation but easily modified during rework, combining the benefits of both stable mounting and ease of repair.
4Area of stationary object
If chip and optical module are positioned adjacent to each other, then space utilization is improved, but electrical signal interference increases
Solution Approach 1:
The patent creates distinct spatial zones within the chip structure: a recessed portion for the optical module and an elevated portion for the chip circuitry. This local differentiation of spatial quality allows the optical module and chip to be positioned adjacent to each other for space efficiency while maintaining physical separation that reduces electrical signal interference. The different heights and spatial zones act as natural isolation barriers.
Data Source
AI summary
The present disclosure provides a package structure having a photonic integrated circuit, the package structure includes a substrate, a chip and an optical module. The chip has an optical waveguide structure and a recessed portion. The optical waveguide structure is adjacent to the recessed portion. The recessed portion faces the substrate, and the chip is engaged to the substrate by flip chip. The optical module is provided in the recessed portion of the chip.