Optical Device Bump Interconnects for High-Speed Integration
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Solution Overview
Problem
Conventional optical devices face challenges in achieving high-speed operation and high integration due to the use of bonding wires, which require precise processing of circuit boards, leading to increased costs and loose connections.
Innovation Solution
The optical device employs a configuration with an optical integrated circuit chip, an electronic circuit chip, and a through wiring board connected via bumps, allowing for easy mounting on a circuit board without high-accuracy processing, using a first bump to connect the optical and electronic circuit chips, a second bump to connect the electronic circuit chip and through wiring board, and a third bump to connect the through wiring board to the circuit board, with an underfill material ensuring secure connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If bonding wire is used for connection, then connection is achieved, but high-speed operation and high integration cannot be materialized
Solution Approach 1:
The patent extracts and eliminates the bonding wire from the connection structure, replacing it with a bump connection method. This removal of the bonding wire enables high-speed operation and high integration by establishing direct electrical and mechanical contact between the optical integrated circuit chip and the driving circuit chip through bumps formed on their respective surfaces.
Solution Approach 2:
The patent replaces the mechanical bonding wire system with a bump-based mechanical and electrical contact system. The bumps provide both structural support and electrical connection, eliminating the need for flexible bonding wires and enabling higher integration density and faster signal transmission.
2Reliability
If mount board is processed at high accuracy, then connection reliability is improved, but cost increases and processing difficulty increases
Solution Approach 1:
The patent segments the connection function into two parts: the bump structure provides mechanical support and positioning, while the electrical connection is established through the bump contact itself. This segmentation allows the mount board to be processed with standard accuracy rather than high accuracy, reducing manufacturing cost while maintaining connection reliability.
Solution Approach 2:
The bump structure serves as an intermediary element that provides both mechanical support and electrical connection between the optical integrated circuit chip and the driving circuit chip. This intermediary eliminates the need for high-precision mount board processing by absorbing positioning tolerances and providing robust mechanical and electrical coupling.
3Ease of manufacture
If processing accuracy is not high, then cost is reduced, but loose connection occurs and modularization is difficult
Solution Approach 1:
The bump structures are formed in advance on both the optical integrated circuit chip and the driving circuit chip before mounting. This preliminary formation of bumps ensures that when the chips are mounted on the board, stable electrical and mechanical connections are automatically established without requiring high processing accuracy during the mounting process itself.
Solution Approach 2:
The patent changes the connection parameter from requiring high positional accuracy to using bump-based mechanical and electrical contact. The bump structures provide tolerance to positional variations, allowing standard processing accuracy to achieve stable connections. The bump geometry and material properties are optimized to maintain connection stability under varying conditions.
Data Source
AI summary
An optical device includes: an optical integrated circuit chip that comprises an optical integrated circuit and an optical interface connected thereto; an electronic circuit chip that comprises an electronic circuit connected to the optical integrated circuit; a through wiring board that comprises a through wiring connected to the electronic circuit chip; a first bump that connects the optical integrated circuit and the electronic circuit between the optical integrated circuit chip and the electronic circuit chip; a second bump that connects the electronic circuit and the through wiring between the electronic circuit chip and the through wiring board; and a third bump connected to an end portion on an opposite side to the second bump of the through wiring. The optical integrated circuit chip and the through wiring board are disposed on a side of a first main surface of the electronic circuit chip. A first distance between the first main surface and a second main surface of the optical integrated circuit chip, the second main surface being on an opposite side to the electronic circuit chip, is equal to or smaller than a second distance between the first main surface and a vertex of the third bump, the vertex being on an opposite side to the electronic circuit chip.